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Alstom LGPG111 Service Manual

1. Bit Name Bit Name 0 System Data 15 Power Prot 1 1 Aux Functions 16 Power Prot 2 2 T former Ratios 17 Frequency Prot 1 3 Disturbance Rec 18 Frequency Prot 2 4 Input Labels 19 Voltage Prot 1 5 Output Labels 20 Voltage Prot 2 6 Remote Comms 21 eg Phase Seq 1 7 Alarm Record 22 eg Phase Seq 2 8 Fault Record 23 Earth Fault 1 9 Event Record 24 Earth Fault 2 10 Current Rating 25 Field Failure 1 11 Generator Diff 1 26 Field Failure 2 12 Generator Diff 2 27 Scheme Logic 1 13 Overcurrent 1 28 Scheme Logic 2 14 Overcurrent 2 Table 20 Bit flag names for the EEPROM Errors cell 6 9 Diagnostic errors Indicates diagnostic messages from the LG PG111 s self testing and monitoring systems Bit FrontPanel Name Remote Access Name 0 LCD Fail LCD Fail 1 Watchdog Inop Watchdog Inoperative 2 Watchdog Fast Watchdog Fast Table 21 Bit flag names for the Diagnostic Errors cell 6 10 No records This cell is the only one visible when there are no event records stored 6 11 Fault record A subtitle cell for the remote access system only the fault record is presented below 6 12 to 6 34 Fault record These cells make up the fault record The first three cells provide status information about the LG PG111 s inputs outputs and protection functions The scheme status cell is included
2. Figure 4 The LG PG111 s front panel user interface See chapter 5 for pin out details of these ports Service M anual R5942B LG PG111 Chapter 6 Page 8 of 91 4 1 1 Display The display isa 2 row by 16 character alphanumeric liquid crystal device and is used to display one cell ata time from the relay s menu The display is refreshed every 500ms or after every key press The 500ms refresh allows the display of cells showing dynamically changing information such as power system measurements in real time 4 1 2 LED status indicators Four LED s provide status indication and are updated every 500ms The red trip LED is illuminated when any trip output has operated The yellow alarm LED flashes when a trip or alarm condition has occurred and remains flashing until all trip and alarm indications have been accepted If any of these conditions are still active when the alarms are cleared the LED stops flashing and remains on Default Display M enu Contents Section Contents GENERATOR _ SYSTEM DATA Password PROTECTION lj N TL AUXILIARY _ Date 1994 Aug 16 FUNCTIONS Time 10 49 50 lj N LGPG111 Menu NW O rganisa tion TRANSFORMER Display Value RATIOS Z Secondary lj TW N MEASUREMENTS 1 Ia l I il t MEASUREMENTS 2 TL oe e VIEW RECORDS View Z Last Record 0 lj N N TECTION FN ry 87G Gen Diff TUS Enabled
3. Relay inoperative alarm Alarm tested Service M anual LG PG111 Scheme logic tests Scheme logic setting group tested R5942B Chapter 9 Page 41 of 52 Bit pattern entered in Set Events for Scheme Results displayed in Scheme O P cell Test cell Service M anual R5942B LGPG111 Chapter 9 Page 42 of 52 INPUT MATRIX OUTPUT MATRIX i i ae Ce ne RHEE HEE Page EE TET ELBTT EE EREEL ray hay 2Gdg2en aSdanhE esggeenn agagddid 282088ee versene L12 L13 L14 L15 E Ls E EEEE EERE EEES EES EEC EEC EEE EE EREHE taste tia ERREP taste ftia REE taste tia Latch outputs TTT TTTJLLTITTIT Fault record trigger TT TT TT LTTTTIT1I Alarm trigger TT CTT L16 L17 L18 L19 L20 L21 L22 L23 L24 L25 L26 L27 L28 L29 L30 L31 Service M anual LGPG111 Stability Checks For 87G Generator Differential Measurements Primary Values la lb Current Measurements la Ib le Kaa lii la a bias Laie a mean bias b mean bias a sensitive Measured Current as Expected Measured Diff Currents Less than 10 of M ean Bias Currents On Load Checks VT Phase Sequence Check VT Phase Sequence Correct Measurements Primary Values Va Vb la ll om Relay M easurements la Ib le residual li lee a bias ine a mean bias eer bias R5942B Chapter 9
4. LG PG111 7 7 View records Item Front Panel 6 0 VIEW RECORDS Psa 6 1 View Last Record 0 6 2 Date 1994 Aug 17 Time 08 17 32 6 3 Exceptions 0000001 6 4 Events 0000000000001 6 5 Relay O P Change 0000000000000001 6 6 Logic I P Change 00000000000100 6 7 Protection Status gt 6 8 EEPROM Errors l 6 9 Diagnostic Error 000 6 10 No Records Stored 6 11 6 12 Protection Status gt 6 13 Relay O P Status 0000000000000000 6 14 Logic I P Status 00000000000000 I 6 15 Scheme Output Enabled 16 16 Active Setting Group 1 6 17 Ta 998mA 6 18 Ib 1 0 A 6 19 Ic 999mA L A S Continued View Records View Last Record 0 Aug 17 1994 08 17 32 349 Exceptions 0000001 Events 0000000000001 Relay O P Change 0000000000000001 Logic I P Change 00000000000100 Protection Status 00000000000000000010 EEPROM Errors 00000000000000000010000000000 Diagnostic Errors 010 No Records Stored Fault Record Protection Status 00000000000000000010 Relay Output Status 0000000000000000 Logic Input Status 00000000000000 Scheme Output Enabled Active Setting Group 1 Ia 998mA ieg 1 000 A Te 999mA Service M anual R5942B LG PG111 Chapter 6 Page 43 of 91 Continued from previous page Item Front Panel Remot
5. Table 23 The LGPG111 s Generator differential Section of its menu Settings for the differential protection function 8 1 Generator differential status The protection function can either be enabled or disabled The setting is password protected 8 2 8 3 8 4 amp 8 5 Differential characteristic These cells specify the bias characteristic Service M anual LG PG111 7 10 Earth fault protection ltem Front Panel Z 9 0 EARTH FAULT PROTECTIO 9 1 51N Stator EF Enabled 9 2 93 51N gt SEF Low Set Char SI 9 4 51N gt SEF Low Set Te gt SmA 95 51N gt SEF Low Set t gt O 1ls 9 6 51N gt SEF Low Set TMS Q 15 9 7 51N gt SEF Low Set CRESET Os 9 8 51N gt gt SEF HighSe Enabled 9 9 51N gt gt SEF HighSet Te gt gt 2 000 A 9 10 5SIN gt gt SEF HighSet t gt gt Os 9 11 59N Neutral Disp Disabled 9 12 59N Neutral Disp Ve gt 1V 9 13 59N Neutral Disp call 1 0 s 9 14 59N Neutral Disp t2 ls 9 15 59N Neutral Disp t2RESET O s 9 16 67N SDEF Enabled 9 17 67N SDEF Ires gt 5mA 9 18 67N SDEF RCA 0 deg 9 19 67N SDEF Vep gt 1V Remote Access Earth Fault Protection 51N Stator Earth Fault Enabled 51N gt Low Set Characteristic Standard Inverse Ie gt 5mA t gt 0 1 s TMS 0 15 tRESET Os 51N gt gt High Set Enabled Te gt gt 2 000 A t g
6. EEPROM WriteFail EEPROM Write Fail Table 18 Bit flag names for the Exception cell Service M anual R5942B LG PG111 Chapter 6 Page 45 of 91 6 4 Events G eneral events Bit FrontPanelName Remote Access Name 0 RtClock Invalid Real Time Clock Invalid 1 RtClock Valid Real Time Clock Valid 2 RtClock Set Real Time Clock Set 3 LPaswrd Removed Local Password Removed 6_ FPaswrd Restored__ Renote Fasavord restore i Table 19 Bit flag names for the Events cell 6 5 Relay output change Indicates the operation of any relay output which is not associated with a fault record trigger See Table 8 page 29 for the bit names 6 6 Logic input change Indicates the energisation of any logic input which is not associated with a fault record The Group Select and Clock Sync logic inputs are however excluded A change in the selected setting group is logged in the events cell and clock synchronising pulses are expected to occur at regular time intervals See Table 7 page 28 for the bit names 6 7 Protection Indicates protection function operations which are not associated with a fault record See Table 10 page 31 for the bit names 6 8 EEPRO M errors Indicates failures to information stored in the non volatile memory EEPRO M of the LGPG111 Service M anual R5942B LG PG111 Chapter 6 Page 46 of 91
7. S S Service M anual R5942B LG PG 111 Chapter 4 Page 28 of 50 W here 12 gt gt is the maximum l2 withstand of the machine in per unit quantity l2 is the measured per unit negative phase sequence current 0 is the temperature C attained when l I2 gt gt 8 4 8 s the initial per unit temperature due to a previous negative phase sequence current Ow 9 is the new per unit temperature due to the applied Ip t is the duration in seconds for the thermal replica to attain Oney from Ooi due to the present I2 applied The maximum temperature measurable by the relay is 10 p u K is the thermal capacity constantin seconds W hen the temperature is increasing the relay setting K is used otherwise the relay setting Kreset is used N ormally both K and Kreset are set equal to the machine s negative phase sequence thermal capacity The relay trips when 9 reaches g If there is no prefault heating i e the initial per Bota unit temperature is 0 and the above formula becomes S 1 L J ew I2 gt gt The operating time can then be derived as 2 en 2 K In i R2 gt gt I2 gt gt I The operating time can be approximated to t K l22 when l is above four times the 12 gt gt threshold W hen high values of K are selected and the negative phase sequence current meas ured is near to the threshold the operating time may be too slow In this case a maximum time setting tM A X is
8. Ib Ic l M easurement of O perating Time Characteristic Injected Current Expected O perating Measured Time O perating Time Measurement of t O perating Time Injected Current Expected O perating Measured Time O perating Time Measurement of t O perating Time Injected Current Expected Operating Measured Time O perating Time 46 gt gt NPS Thermal Trip Reset Time Time Allowed for Expected Time for Measured Time for Cooling seconds Second O peration Second O peration Injected Current Operation Of Output Relays for 46 gt gt NPS Thermal Trip Correct Operation Of Output relays N otes Service M anual R5942B LGPG111 Chapter 9 Page 34 of 52 81U 1 Under Frequency Tests carried out with Variable Frequency Fixed Frequency Supply Measurements Injected Frequency l Measured Frequency Measurement of F1 lt Fl lt tl Expected Pick up Measured Pick up Measured Drop off Frequency Frequency Frequency Measurement of Operating Time Expected Operating Measured Operating Time Time Operation Of Output Relays Correct Operation Of Output relays 81U 2 Under Frequency Tests carried out with Variable Frequency Fixed Frequency Supply Measurements Injected Frequency Measured Frequency Measurement of F2 lt Service M anual R5942B LGPG111 Chapter 9 Page 35 of 52
9. a sensiitive Pe Check of pick up value I gt setting R Expected pick up Measured pick up Expected drop off Measured drop off Measurement of time delay characteristics Expected time Measured time DT SI 2x I gt Oooo d E S1 10x I gt Fault record checks Fault records match injected faults o E Thermal curve characteristic Injected current Expected trip time M easured trip time Expected 2 current Measured 2 current Service M anual R5942B LGPG111 Chapter 9 Page 11 of 52 Voltage based protection Measurements Expected voltage Measured voltage Check of pick up value I gt setting Geet ee ee ee Expected pickup Measured pick up Expected drop off Measured drop off Measurement of time delay characteristic Expected time Measurement of frequency Expected Measured Fault record checks Fault records match injected faults E Power based protection Measurement of phase angle Expected phase angle M easured phase angle Expected power reading M easured power reading Measurement of RCA Expected Pick up Values M easured Pick up Value lead M easured Pick up Value lag M easured Drop off Value lead M easured Drop off Value lag Service M anual R5942B LGPG111 Chapter 9 Page 12 of 52 Input Status Checks Relay Terminal Input Status Results as expe
10. Printer does not respond relay indicates printer is busy or prints and stops The most probable cause for this is the connection lead The LG PG 111 does not have a standard IBM PC printer port so standard printer connection leads must be modified Either make up a dongle style adapter or remove the inappropri ate connections from the lead see the front panel description in chapter 5 Another typical cause of this problem is a faulty paper out detector in the printer This will cause the relay to report the printer is busy Check the printer is working with a self test or better still with another device such as a computer Assuming the printer works then the fault is either with the connection lead or with the parallel port on the relay Check the connection lead carefully If an IBM PC style computer is available try the connection lead including the adapter dongle using the printer and computer to print something If this works OK then the front panel portis probably at fault Printer accepts data from the relay but prints random characters or nothing Two probable causes i Connection lead including adapter dongle has open circuit short circuit or crossed data bit wires ii Printer is nota plain text ASCII printer For example most PostScript printers will not print plain text data Printed output is double spaced The LGPG111 terminates each line with a carriage return and line feed Some printers will automatically generate a l
11. Provides an indication of the relay s alarm status as indicated by the front panel alarm LED The cell has three display states see Table 11 Normally the N ot Present message is displayed W hen there are alarms this is replaced by Present The alarm indication can be reset by entering setting mode This will also cause latched output contacts to be reset The display then reverts to displaying N ot Present The remote access setting transfer does not include this cell 2 6 2 7 Front Panel Relay Alarms Relay Alarms Not Present Not Present Relay Alarms Relay Alarms Present Present Press SET To Clr Relay Alarms Clear Alarms amp Latched Alarms amp Latch O P Contacts Table 11 States of the relay alarms cell Scheme output Controls whether the output from the scheme logic drives the output relays The cell has two states enabled and inhibited The cell is password protected The enabled state means the scheme logic is controlling the output relays This is the state for normal protection operation The inhibited state means the scheme logic is not controlling the output relays and the LG PG111 s Out Of Service LED will be on In this state the relay outputs can be operated manually with the Relay Test cell in the Test Functions Section The relay output status cell will however reflect the current output state from the scheme logic This allows testing of the relay without operatin
12. l Value of current injected into the Bias coil mean bias Service M anual R5942C LG PG111 Chapter 8 7 1 4 7 2 Page 23 of 66 laa Trip level Value of current injected into the Diff coil Record the and above Acceptall the alarms and reset them mean bias diff Repeat for all three phases Upper slope The expected trip level I can be calculated from the following equation ait lai Trip level Is1 K1 x Is2 K2 x I Is2 with a 5 tolerance mean bias Inject 1 5 x Is2 Amps into the Bias coil and then inject 0 5 x Isl Amps into the Diff coil Slowly increase the current injected into the Diff coil until the relay operates If 1 5 x Is2 is greater than the relay s maximum continuous rating of 4xIn the current should only be injected for a short duration to avoid damaging the relay The measured mean bias and differential currents for A phase element are l Value of current injected into the Bias coil mean bias laa Trip level Value of current injected into the Diff coil Record the and above Accept all the alarms and reset them mean bias diff Repeat for all three phases Fault record checks Use the front panel keys to navigate to the menu section View Records and ensure that the records match the injected faults carried out above 32R Reverse power Reverse power protection is used to guard against the loss of the prime mover and hence prevent mo
13. 11 7 11 8 amp 11 9 Low forward power settings Item Front Panel Remote Access 11 0 POWER Power Protection PROTECTION 11 1 Power Prot Compensation Angle 0 deg 8comp 0 deg 11 2 32R Reverse Pwr 32R Reverse Power Enabled Enabled 11 3 32R Reverse Pwr P gt 5 00 W P gt 5 00 W 11 4 32R Reverse Pwr t Pickup 2 0 Ss see 2 0 s 11 5 32R Reverse Pwr tDO Dropoff Os tDO Os 11 6 32 Oow Fwd Pwr 32L Low Forward Power Enabled Enabled 11 7 32L Low Fwd Pwr P lt ITS W P lt 1 75 W 11 8 32L Low Fwd Pwr Pickup 20S t 2 0 08 111 9 32L Low Fwd Pwr tDO Dropoff 0S tDO Os Service M anual R5942B LG PG111 Chapter 6 7 13 Page 57 of 91 Frequency protection Item Front Panel Remote Access 12 0 FREQUENCY Frequency Protection PROTECTION 12 1 81U 1 Under Freq 81U 1 Under Frequency Enabled Enabled 12 2 81U 1 Under Freq F1 lt 48 00 Hz Fl lt 48 00 Hz 12 3 co 8 0 s 12 4 81U 2 Under Freq 81U 2 Under Frequency Enabled Enabled 12 5 810 2 Under Freq F2 lt 46 00 Hz F2 lt 46 00 Hz 12 6 81U 2 Under Freq E2 0 2 Hz t2 0 2 8HZ 12 7 810 Over Freq 810 Over Frequency Enabled Enabled 12 8 810 Over Freq F gt 55 00 Hz F gt 55 00 Hz 12 9 810 Over Freq tx 5 0 s t 5 0 s Table 32 The LGPG111 s Frequency Protection Section of its menu Settings
14. P n Prim x Sp x CT x VT 3 P_ Sec m W here P Sec Secondary 1 phase motoring power W atts P Prim Percentage motoring power of generator set S Generator rating VA CT Protection CT ratio VT Protection VT ratio The operating boundary of the reverse power protection function should be where the A phase current flowing from the generator into the power system lies within a of the derived inverted A phase voltage signal P gt x V3 x 180 a 90 1 05 x Vab XT The position of the positive angle is indicated in Figure 13 The operating criteria is according to the following formula see Figure 13 Vab 30 x laCos I8O v3 gt P gt W here V Phase phase voltage signal used AB l Current from sensitive input CT A Angle between in export direction and V P gt LGPG111 reverse power threshold setting 1 phase secondary W atts In a practical relay design the operative angle range must be slightly less than 90 to allow for small CT VT and relay errors These errors might otherwise result in false protection operation with low power factor forward current e g when supplying excitation current to a step up transformer prior to synchronisation The angular operating range must not be reduced too much since the reverse power protection may be required to respond to a small level of reverse active current e g 0 5 n while a much larg
15. Service M anual R5942B LGPG111 Chapter 9 Page 19 of 52 32R Reverse Power Measurements __ Injected Values _Measured Values _ Laane Va Phase Power I Vin Phase Power CC Angle Watts Angle Watts Po T O S e i EY Characteristic Checks P t tDO Expected Pick up Power Measured Pick up Power Measured Drop off Power Measured O perating Time Operation of Output Relays Correct Operation Of Output relays Service M anual LGPG111 32L Low Forward Power Measurements Injected Values R5942B Chapter 9 Page 20 of 52 M easured Values eevee Va Phase Power l ii Van Phase Power Angle Watts Angle W atts Characteristic Checks P t tDO Expected Pick up Power M easured Pick up Power Measured Drop off Power M easured O perating Time Operation of Output Relays Correct Operation Of Output relays Notes Service M anual R5942B LGPG111 Chapter 9 Page 21 of 52 40 Field Failure Measurements Injected Values Measured Values Values Measured Values Current Voltage Phase Va Phase Angle Angle _ Characteristic and Operating Time Xa Xb t tDO Measurement of Xa Xb Expected Pick up Injected Current Injected Voltage Measured Pick up Value ohms Value ohms Measurement of Xa Expected Pick up Injected Current Injected Voltage Measured Pick up Value ohms Value ohms Measurement of O perating Time Me
16. This setting is password protected 10 3 Voltage vector rotation Determines whether the phase to phase voltage measurements are rotated before being applied to the selected voltage dependent characteristic This allows compensation for vector rotation incurred by a generator transformer and allows the overcurrent function to act correctly as backup protection for the high voltage side This cell is password protected z Front Panel Remote Access l Ee Overcurrent Voltage Vector Rotate None Rotate None 51V Overcurrent Voltage Vector Rotate Yd Rotate Yd Table 28 States of the vector rotate cell The effects of the rotation settings are summarised in Table 29 for each phase current there is a voltage input to the voltage dependent characteristic Service M anual R5942B LG PG111 Chapter 6 Page 55 of 91 CurrentPhase None Yd lt Vab Va Va i Moc Va g Va I Ve Ve JB Table 29 Voltage dependencies for each phase current verse vector compen sation setting 10 4 10 5 10 6 amp 10 7 Voltage dependency characteristic settings 10 8 Timing characteristic selector Specifies the timing characteristic can either be a standard inverse definite minimum time or a definite time characteristic Front Panel Remote Access Char 51V eee Characteristic Standard Inverse Characteristic Definite Time 51V Ove
17. 26 26 26 26 26 28 28 28 30 30 31 31 32 32 32 32 32 33 33 34 34 34 34 34 Service M anual LGPG111 81U 2 Under Frequency M easurements Measurement of F2 lt Measurement of O perating Time O peration Of O utput Relays 810 Over Frequency M easurements Measurement of F gt Measurement of O perating Time O peration Of O utput Relays 27 Under Voltage M easurements Characteristic and Operating Time O peration Of O utput Relays 59 Over Voltage M easurements Characteristic and O perating Time O peration Of O utput Relays 60 Voltage Balance Measurement Checks Characteristic Checks for 60 VB Prot Characteristic Checks for 60 VB C omp O peration of O utput Relays Input Status Checks Relay output tests Relay inoperative alarm Scheme logic tests R5942B Chapter 9 Page 6 of 52 34 34 34 35 35 35 35 35 35 36 37 37 37 37 37 37 37 38 39 39 39 39 39 40 40 40 41 Service M anual LGPG111 Stability Checks For 87G Generator Differential M easurements On Load Checks VT Phase Sequence Check M easurements Final Setting Checks System Parameters Final Settings Applied To The Relay Generator Differential Earth Fault Protection Voltage Dependent O vercurrent Power Protection Frequency Protection Voltage Protection N egative Phase Sequence Field Failure Signatures R5942B Chapter 9 Page 7 of 52 43 43 43 43 4
18. A password protected 16 character string Principal application is to identify the product and possibly its application when viewed over the remote access system The remote access setting transfer does not include this cell For software versions before 18LG PG 002 XXXEB this cell was a non settable cell containing a description of the protection namely Generator Protection Plant reference A password protected 16 character string Principal application is to identify the location of the product when viewed over the remote access system The remote access setting transfer does not include this cell M odel number A password protected 16 character string The cell identifies the particular model number of the LG PG 111 over the remote access system Use of replacement microprocessor modules makes it necessary to alter this cell This is so that the model number in the menu matches the model number printed on the information label inside the relay s case The remote access setting transfer does not include this cell Serial number A password protected 7 character string Principal application is to identify the serial number of the LGPG111 over the remote access system Use of replacement microprocessor modules makes it necessary to alter this cell This is so that the serial number in the menu matches the serial number printed on the information label inside the relay s case The remote access setting transfer does not i
19. Frame Check Sum 16 bit summation CRC 16 Transmission Mode Half duplex asynchronous Half duplex synchronous start with synchronous frames HDLC with biphase FM 0 encoding Message Format Courier Courier Ports Fully connected 25 pin Three terminal K Bus port D Type female at the rear atthe rear using 4mm Partially connected 25 pin screws D Type female at the front Modem Compatibility Yes rear port only No Table 2 Comparison of the two communications protocols available in the LGPG111 5 2 Connections The LGPG111 provides three communications ports only one of which can be used at any one time Of the three two are RS232 compatible using IEC870 protocol and one uses the ALSTOM T amp D Protection amp Control Limited K Bus which is based on the twisted pair RS485 specification Table 2 summarises the two available communications protocols The front IEC870 portis designed for temporary connection in such circumstances as commissioning It has no isolation to earth and no modem capability However it is easily accessible with the front cover removed The rear IEC870 portis designed for permanent connection to either a locally sited system or to a modem It offers a high isolation level and provides all the RS232 modem control signals The rear K Bus port is also designed for permanent connection with a higher isolation level of 2kV K Bus can be directly connected to systems with a synchronous HDLC RS485 twisted pair
20. LG PG 111 3 3 3 3 1 3e3a 2 3 4 3 4 1 Chapter 4 Page 20 of 50 Neutral displacement 59N General description The neutral displacement protection function is voltage operated from the V input Two definite time outputs are provided The function is inherently immune to third harmonic components due to the Fourier filter An adjustable timer hold facility is available for the second timer output as explained in Section 3 12 Settings and protection characteristic The settings provided are as follows Ve gt N eutral voltage threshold tl Timer 1 setting t2 Timer 2 setting t2 RESET Reset time for the timer hold Applied to timer 2 output only The characteristic is illustrated in Figure 11 Figure 11 N eutral displacement characteristic Sensitive directional earth fault 67N G eneral description The sensitive directional earth fault protection is dual polarised The operating quantity is the residual current signal a The polarising quantity is either the voltage signal V Or a Current signal If the polarising voltage is not available then the polarising Current is used The function is inherently immune to third harmonic components due to the Fourier filter A relay characteristic angle RCA is provided which is only applied when V is used as the polarising signal The function is instantaneous in operation The directional calculation is evaluated approximately every 20m
21. Table 25 States of the stator earth fault low set timing characteristic cell Depending upon the value of the timer characteristic cells 9 5 and 9 6 are alternatively visible cell 9 5 is visible for the definite time characteristic and cell 9 6 is visible for the standard inverse characteristic 9 8 9 9 amp 9 10 high Set Characteristic Settings Cell 9 8 Allows the high set element to be enabled or disabled the high set is disabled along with the low set when the function s status is disabled This setting is password protected 9 11 Neutral displacement status The protection function can either be enabled or disabled The setting is password protected Service M anual R5942B LG PG111 Chapter 6 Page 52 of 91 9 12 9 13 9 14 amp 9 15 Neutral displacement characteristic settings 9 16 Sensitive directional earth fault status The protection function can either be enabled or disabled The setting is password protected 9 17 9 18 9 19 amp 9 20 Sensitive directional earth fault characteristic settings Service M anual R5942B Chapter 6 Page 53 of 91 Remote Access LG PG111 7 11 Voltage dependent overcurrent Item Front Panel 10 0 V DEPENDENT Voltag OVERCURRENT 10 1 51V Overcurren 51V Overcurrent Enabled 10 2 51V Overcurren Fn Restrain 10 3 51V Overcurren Voltage Vector Rotate None Rotate one 10 4 51V Ove
22. are injected voltage and current respectively The phase angle between l sensitive and V measured on the relay should be 180 degrees with a tolerance of 5 Stop the current injection Reset all alarms Alternatively if the available test equipment cannot provide a phase shift inject rated volts into B25 B26 and rated current in anti phase to the voltage into A9 A10 The phase angle now measured by the relay should read 150 The measured active power should be 1x V x cos30 V3 Watts allowing 5 tolerance where V and are injected voltage and current respectively and cos30 0 866 Characteristic and operating time Record the reverse power protection settings P tand tDO W ith the current leading the voltage by 150 apply rated voltage terminals B25 B26 inject zero Amps into the relay A9 A10 and slowly increase the current to check the 32R Reverse Power pick up and drop off values Record the current injected Pick up Power Measured pick up current x Rated voltage V3 Service M anual R5942C LG PG111 Chapter 8 Peet 7 3 sialic Page 25 of 66 Check that the measured value is within 5 of the set value P The Drop off value should be within 95 of the pick up value W ith the connections and conditions as above inject a current of twice the pick up value to obtain the operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay trips Check ALARM P
23. 15 W ith some gear driven sets damage may splitshaft arise due to reverse torque on gear teeth gt 50 Single shaft Compressor load on single shaft machines leads to a high motoring power compared to splitshaft machines Rapid disconnection is required to limit power loss or damage Hydraulic 0 2 gt 2 Blade and runner cavitation may occur with a Turbines Blades out of water long period of motoring gt 2 0 Blades in water Power is low when blades are above tail ace water level Hydraulic flow detection devices are often the main means of detecting loss of drive Automatic disconnection is recommended for unattended operation Steam Turbines 0 5 3 Thermal stress damage may be inflicted on Condensing sets low pressure turbine blades when steam flow is not available to dissipate windage losses 3 6 N on condensing sets Damage may occur rapidly with non condensing sets or when vacuum is lost with condensing sets Reverse power protection may be used as a secondary method of detection and might only be used to raise an alarm Table 1 Motoring power and possible damage for various types of prime mover The need for automatic disconnection is arguably less for plant that is continuously supervised but in the event of prime mover failure the attention of control staff could be diverted by other aspects of the mechanical failure If motoring damage can occur rapidly operator action may be
24. 2 11 Over voltage protection function 59 53 2 12 Under frequency protection function 81U 54 2 13 Over frequency protection function 810 56 2 14 Voltage balance protection function 60 57 3 O THER PRO TECTIO N CONSIDERATIONS 59 3 1 Dead machine protection 59 Bal Breaker flashover protection 61 3 3 O ver fluxing protection 62 3 4 interlocked overcurrent protection 63 3 5 Pole slipping protection 64 Service M anual LG PG 111 Sel 3 5 2 4 5 Id 5 1 1 5 1 2 5 2 5735 5 3 1 5 3 2 5 4 5 5 Jel 5 5 2 5 6 R5942B Chapter 3 Page 4 of 75 Voltage dependent overcurrent protection function 51V 65 Field failure protection function 40 66 STAN DARD FACTO RY SETTINGS 70 CURREN T TRAN SFO RM ER REQ UIREM EN TS 71 Generator differential function 71 Biased differential protection 71 High impedance differential protection 12 Voltage dependant overcurrent field failure and negative phase sequence protection functions 72 Sensitive directional earth fault protection function residual current input 72 Line current transformers 72 Core balanced current transformers 73 Stator earth fault protection function and sensitive directional earth fault current polarising input 73 Reverse and low forward power protection functions 73 Protection class current transformers 74 M etering class current transformers 74 Converting an IEC60185 current transformer standard protection classification to a kneepoint voltage
25. 7 8 2 Page 37 of 66 Characteristic and operating time for restraint function Record the voltage restrained overcurrent settings Voltage rotation Vs1 Vs2 K I gt t TMS tRESET and the Definite Time DT or Standard Inverse SI characteristic applied The following tests should be applied to each phase element complete the tests for each element in turn Begin by testing phase A For this function it is necessary to test three points on the curve for each phase Current Pick up Level The following connections will be required during these tests Signal designator LGPG111 Connections la A11 A12 Ib A13 A14 Ic A15A16 Vbc B2728 Vea B25 B28 Link B26 B27 Vab B25 B26 Link B25 B28 amp B26 B27 M easurement of I gt point 1 For the different voltage vector rotation setting s inject the voltage as follows for each phase Voltage Phase A Phase B Phase C Rotation Inject Inject Inject Setting None I gt into la 1 2xVs1 l gt into Ip 1 2xVs1 I gt into Ic 1 2xVsl into Vab into Vp into Vea Yd I gt into la 1 2xVs1 l gt into Ip 1 2xVs1 I gt into Ic 1 2xVsl into Vab into Vap into Vc Service M anual R5942C LG PG111 Chapter 8 Page 38 of 66 Inject the specified current and voltage to check the pick up and drop off values As there is a time delay associated with this function the Protection O peration Summary Section of the relay s menu can be
26. Diameter t Pickup tDO Dropoff yi 225 Ji ye k End of Report 2 5 Ohm 0 0 Ohm 1 0 s Os Service M anual LG PG111 8 3 Scheme logic LGPG RELAY Serial Number Printed on Tue 1994 Aug 23 Scheme Logic lt Not Defined gt 0000000 Latch Outputs Fault Record Trigger Alarm Record Trigger Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic End 00 01 02 03 04 05 06 07 08 09 AANA OF WN 10000000 01000000 00100000 00001000 00000100 00000010 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 1 00000000 Report INPUT 00000000 00000000 00000000 00000000 00000000 00000000 00000000 10000000 01000000 00100000 00010000 00001001 00000100 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 16 34 48 000000000000000 100000000000000 000000000000000 MATRIX 00000000 00100000 00100000 00000000 00000000 00000000 00100000 00100000 00000000 00000000 00000000
27. F2 lt 2 Expected Pick up Measured Pick up Measured Drop off Frequency Frequency Frequency Measurement of Operating Time Expected Operating Measured Operating Time Time Operation Of Output Relays Correct Operation Of Output relays 810 Over Frequency Tests carried out with Variable Frequency Fixed Frequency Supply Measurements Injected Frequency Measured Frequency Measurement of F gt F gt t Expected Pick up Measured Pick up Measured Drop off Frequency Frequency Frequency Measurement of Operating Time Expected Operating Measured Operating Time Time Eee eee Service M anual R5942B LGPG111 Chapter 9 Page 36 of 52 Operation Of Output Relays Correct Operation Of Output relays N otes Service M anual R5942B LGPG111 Chapter 9 Page 37 of 52 27 Under Voltage Measurements Injected Voltage Measured Voltage Measured Voltage Vab Vbc Characteristic and Operating Time V lt t Measurement of V lt Input Expected Pick up Measured Pick up Measured Drop off Voltage Voltage Voltage Vab Vbc Measurement of Time Delay Characteristic Expected Operating Measured Operating Time Time Operation Of Output Relays Correct Operation Of Output relays 59 Over Voltage Measurements Injected Voltage Measured Voltage Measured Voltage Vab Vbc Characteristic and Operating Time V gt b V gt gt t gt Measurement of V gt Expected Pick up
28. If this angular boundary is expressed as the angle between canctive 4nd Va then a is given by the equation P gt pE 105x V a a 90 sn For small angles from the horizontal axis gp 29 9 The equation then becomes Service M anual R5942B LG PG111 Chapter 4 Page 26 of 50 NO TRIP NO TRIP Reverse power characteristic Low forward power characteristic Figure 16 Reverse power and low forward power relay characteristics NO TRIP Figure 17 Angular boundary for the reverse power function Be gt x V3 x 180 a 90 105x Vp XT The angular boundary is therefore dependent on the setting P gt and on Vp If V is maintained atthe nominal voltage of say 100V the angular boundary for P gt 0 3W is 89 7 and when P gt 1 W itis 89 1 Service M anual R5942B LG PG111 Chapter 4 3 7 3 7 1 3 7 2 Page 27 of 50 Negative phase sequence thermal protection 46 General description The negative phase sequence protection function provides a thermal replica characteristic which can be set to closely match the negative phase sequence withstand characteristic of the protected generator The implementation of the thermal characteristic allows for pre fault heating of the machine due to standing negative phase sequence current present under normal healthy running conditions to be simulated A separate definite time negative phase sequence overcurrent alarm element is also provided
29. JM1 lnk 12 Calibration JM3 Link 2 3 CAUBRATION OF RELAY ONLY 1 2 N ormal position ZH1010___ a lysasaes 16 JM2 3 s 8 JM3 2 Figure 5 Analogue and status input module link positions pcb no ZH1010 Service M anual R5942B LG PG111 Chapter 5 6 5 Page 23 of 23 JM3 ZH1017_ 23 ONS JM2 Figure 6 Analogue and status input module link positions pcb no ZH1017 Front panel operator interface The front panel has one link which disables a push button initiated reset of the LG PG111 See Figure 7 for the Front Panel O perator Interface link positions yma n 12 ZHO7979_ JM1 13 Figure 7 Front panel operator interface link positions Chapter 6 User Interface Service M anual LG PG111 Issue Control engineering document number Issue Date AP February 1995 BP June 1995 A July 1995 B Feb 1996 Author Dave Banham Dave Banham Dave Banham Publicity Dave Banham Publicity R5942B Chapter 6 Page 2 of 91 50005 1701 106 Changes Original Minor corrections and layout improvements Styles changed Features for software version 18LG PG002XXXEB onwards added i Paragraph added to Scheme O utput cell in auxiliary functions to indicate that the state of the cell is now logged at reset
30. PARALLEL is a parallel input and output port The port is capable of driving a parallel printer as well as providing access to all the internal power rails Table 16 gives the pin out information for both the parallel printer and voltage rail connections Pin N umber Function Direction 1 Protective G round 2 Received Data In 3 Transmitted Data O ut 4 amp Connected 5 Together 7 Signal G round 6 Connected 8 amp Together 20 Table 15 Connection for the front panel RS232 serial connector Standard PC interface cables should be used for both ports However the connections will need to be modified for the printer as shown in Table 16 It is essential that the cable screen is earthed at one end to ensure adequate screening The connectors should be screw locked at each end Reference should be made to the PC user manual for the exact serial connection requirements and to the printers manual for the parallel port connection There is no electrical isolation on either the serial port or the parallel port An external isolation barrier with transient suppressers should be used if the earth potential of the connected equipment differs from that of the relay The front panel operator interface is powered by the 6 5V rail of the I O bus 6 REPLACEMENT MODULE HARDWARE CONFIGURATION The modules used in the LGPG111 are selected from a standard hardware range Pins on the 25 way connector not detailed are not connected
31. Page 43 of 52 12 l cdiff cbias cmean bias Ic 12 lar chias cmean bias Service M anual LGPG111 a sensitive Vab Vbc Ve Frequency ab comp Active Power Aph Reactive Power Aph Phase Angle Aph Measured Current and Voltage as Expected Measured Diff Currents Less than 10 of M eanBias Currents M easured I2 as Expected Active and Reactive Power M easurements Correct Final Setting Checks Date and Time on Relay Correct Settings Applied to Relay Scheme Setting O K System Parameters Diff CT Ratio Residual CT Ratio Earth VT Ratio Phase CT Ratio Final Settings Applied To The Relay System Data Password System Frequency Auxiliary Functions R5942B Chapter 9 Page 44 of 52 Vca bc comp Ld Sensitive la Ratio Comp VT Ratio Earth CT Ratio Line Vt Ratio Plant Reference Service M anual LGPG111 Scheme O utput Second Setting Group Active Setting Group Inactivity Timer Clock Synchronized Display Value Select Setting Group Stator E F Timer Inhibit Remote Setting Default Display R5942B Chapter 9 Page 45 of 52 Service M anual LGPG111 Group 1 Settings Generator Differential R5942B Chapter 9 Page 46 of 52 Group 2 Settings 87G Generator Diff Enabled Disabled Isl K1 Is2 K2 Earth Fault Protection 51N Stator Earth Enabled Disabled Fault 51N gt Low set SI
32. The protective ground is connected to the case which is connected to OV of the relay Service M anual R5942B LG PG111 Chapter 5 Page 19 of 23 Pin Number Parallel Printer Connection Test Port Connection Level 1 Strobe DoNotConnect TL 2 Data Bit 0 TTL 3 Data Bit 1 TTL 4 Data Bit 2 TTL 5 Data Bit3 TTL 6 Data Bit 4 TTL 7 Data Bit 5 TTL 8 Data Bit 6 TTL 9 Data Bit7 E 10 Do N ot Connect RESET Key I ite 11 Busy Do NotConnect TIL 12 Do N ot Connect ACCEPT READ Key TL 13 Do N ot Connect SET Key at 14 Do N ot Connect e Key r 15 Do N ot Connect J Key i mL 16 Do N ot Connect Key il 17 Do N ot Connect T Key TEL 18 DoNotConnect 6 5V Via 10kQ 19 DoNotConnect 19 5V Via 10kQ 20 Do NotConnect 19 5V Via 10kQ 21 Do N ot Connect 24V Via 10kQ 22 Ground G round 23 Ground G round 24 Ground G round 25 Ground G round Table 16 Front panel parallel port pin connections for parallel printer and test port M any of the modules have a number of jumper links which must be set to allow them to be used in particular applications The following Section lists the link positions required by modules in the LG PG 111 All links must be fitted as shown The followi
33. current to check the drop off value As there is a time delay associated with this function the Protection O peration Summary Section of the relay s menu can be used to determine the point at which this function starts to operate The Protection O peration Summary should indicate 0 when the current injected is increased to the pick up point the displayed percentage will start to increase this is the pick up point the displayed value will rise from 0 and displays 100 when the time delay has expired Accept and reset all alarms pick up value I gt setting with a 5 tolerance drop off value 0 95xI gt setting with a 5 tolerance Repeat the tests for phases B and C Measurement of time delay characteristic Inject 2 x I gt Amps to obtain the operating time Check the red LED turns on and the yellow Alarm LED flashes when the relay operates Check the ALARM Protection 51V OC A appears on the display where a is the phase designator for the phase Service M anual R5942C LG PG111 Chapter 8 7 8 5 7 8 6 7 9 Page 43 of 66 under test Ignore other alarms Reset all alarms Record the operating time For the DT characteristic O perating time t seconds with a 5 tolerance 10mS to 40mS where tis the applied setting For the SI characteristic O perating time 10xTMS seconds with a 5 tolerance 10mS to 40mS where TMS is the applied setting Repeat the tests for phases B and C Fau
34. current until the display reaches 95 stop injection then inject the required 3 x I2 gt gt and slowly increase until the display reaches 100 Record the current injected Pick up current 3xl2 gt gt with a 7 5 tolerance Repeat the tests for the input terminals A13 A14 and the input terminals A15 A16 M easurement of operating time characteristic For measuring relay operating time allow atleast 4xKreset seconds between timings to allow the thermal element to reset allow to cool until the relay displays a thermal value off 0 N ote the thermal value will be reset to 0 if the auxiliary supply to the relay is switched off Inject 6 93 x 12 gt gt Amps into the and inputs so that phases A and B are in anti phase terminals A11 A13 with A12 and A14 linked to obtain the relay operating time The I2 measurement displayed in the relay should indicate 4x12 gt gt for this condition for two currents in opposite polarity I V3 therefore 4 x 1 6 93 x I The following equation is derived from the equation stated in section 7 9 If itis desired to inject any other value of current other than 4 x 12 gt gt then the equation given in section 7 9 should be used to calculate the expected tripping time 0 0645 x K expected operating time _ 2 gt gt where I2 gt gt amp K are the relay settings In is the relay s current rating 1A or 5A Allow 10 tolerance 10mS to 50mS Check the red Trip
35. reflect change in LGPG111 functionality for version 18LG PG002XXXEA onwards The N PS reset characteristic was an exponential decay now the thermal replica is used Kreset was the time constant of the exponential now itis the thermal capacity constant for cooling The commissioning test results report Section has been removed and placed in a separate document 50005 1701 111 as Error AutoText entry not defined This is to facilitate extra copies being ordered Publicity A July 1995 Dave Styles Banham Publicity B Feb 1996 Dave Section 5 11 5 corrected timing formula Banham added timing formula for commissioning Publicity software versions prior to 18LGPGO02XXXEA C June 1997 Andy Addition of new section for commissioning as Forshaw One unit section 6 Major re write of the old sections All tolerances corrected Service M anual R5942C LG PG111 Chapter 8 Page 3 of 66 Contents 1 GEN ERALN O TES 7 2 TEST EQ UIPM EN T REQ UIRED 8 3 COMMISSIONING PREUM IN ARIES 8 3 1 Handling of electronic equipment 8 3 25 Inspection 8 3 2 1 Earthing 9 3 3 M ain current transformers 9 3 3 1 Insulation 9 3 3 2 Wiring checks 10 4 AUXILIARY PO W ER SUPPLY TEST 10 4 1 Relay auxiliary voltage Vx1 10 4 2 O ptically isolated logic input supply Vx2 10 4 3 Energizing the LGPG111 11 4 4 Testing the power supply failure alarm 11 4 5 Testing the LED s 11 aye SECONDARY INJECTION TESTS PRELIM IN
36. should form the basis of the generator manufacturer s shorttime per unit lt withstand claim Many traditional forms of generator N PS thermal protection relays have been designed with an extremely inverse I t operating time characteristic This characteristic would be set to match the claimed generator thermal capacity For intermediate levels of negative phase sequence current the rate of heating is slower As a result heat dissipation should be considered The basic expression of Service M anual R5942B LG PG111 Chapter 3 Page 45 of 75 t K lm does not cater for the effects of heat dissipation or for low standing levels of negative phase sequence current The latter resulting in an increase in rotor temperature which remains within the machines design limits An existing tolerable level of negative phase sequence current l lt l w has the effect of reducing the time to reach the critical temperature level if the negative phase sequence current level should increase beyond The LGPG1 111 NPS thermal replica is designed to overcome these problems by modelling the effects of low standing levels of negative phase sequence currents The temperature rise in critical rotor components is related to the negative phase sequence current I per unit and to time t seconds as follows This assumes no preceding negative phase sequence current 6 Ca Pal eth where Kg tis the thermal time constant 7 2 l2 CMR K is the
37. 000100000000000 0 101000000000000 0 text was given but was not understood Then the Scheme O P cell should display 1 Scheme O P 100000000001000 As operation of 321lLow Forward Power AND 40 Field Failure AND 60 Voltage Balance Block will cause the operation of output contacts R4 and R15 This test will not cause operation of the output contacts as itis designed to prove the scheme logic without the need to secondary inject and operate contacts W hen two setting groups are used both groups scheme logic will need to be tested The Test Functions Section provides two sets of scheme test cells one for each group WIRING CHECKS For many of the functions of the relay the polarity and phase rotation of the current and voltage inputs is critical for their correct operation It is essential that tests are carried out to ensure that the primary CT s and VT s are of the correct polarity and that the polarity and phase rotation is correct throughout the wiring from the CT s and VT s to the connections on the rear of the relay As each installation and the type of test equipment available is different from site to site itis difficult to provide any meaningful instructions However it is strongly recommended that primary injections are carried out If a test set capable of providing three phase volts and current is available that secondary injections are carried from a point close to the CT an
38. 10 LGPG111 00 in chapter 11 Service M anual R5942C LG PG 111 332 4 1 4 2 Chapter 8 Page 10 of 66 W iring checks Check that the external wiring is correct to the wiring schedule or scheme diagram If MMLG test blocks are provided the connections should be checked to the scheme diagram particularly that the supply connections are to the live side of the test block coloured orange with odd terminal numbers AUXILIARY POWER SUPPLY TEST CAUTION The relay can withstand some AC ripple on its DC auxiliary supplies however the peak value of the auxiliary supply should not exceed the maximum withstand value Do not energize the relay from a supply with the batteries disconnected and the system run from the charger alone The LGPG111 is fitted with transient suppression circuits which are designed to protect it from potential damage by intermittent spikes of short duration Relay auxiliary voltage Vx1 Before applying the auxiliary supply to the LGPG111 check the polarity of the power supply wiring corresponds to the relay s connections terminal H13 is positive ve and H14 negative ve Remove the auxiliary supply s fuse and isolation link and check the polarity and measured value of the auxiliary supply The supply must be within the operating range specified for Vx 1 in the following table Replace the isolation and fuse links Nominal Vx1 24 27V 30 34V 48 54V__ 110 125v 220 250Vv Op
39. 11 Input 11 Input 12 Input 12 Input 13 Input 13 Output Contact Labels Output 1 Gen Diff Trip Output 2 Overcurrent Trip Output 3 Reverse Pwr Trip Output 4 Over Freq Trip Output 5 Under Freq Trip Output 6 O Voltage Trip Output 7 U Voltage Trip Output 8 NPS Trip Output 9 NPS Alarm Output 10 Volt Bal Operate Output 11 Relay 11 Output 12 Relay 12 Output 13 Field Fail Trip Output 14 Relay 14 Output 15 Trip CB Remote Communications Relay Address 1 Remote Setting Enabled Communications Mode Rear IEC870 FT1 2 Transmit Delay Os Serial Baud Rate 9600 Disturbance Recorder Recorder Status Running Data Capture Raw ADC Samples Post Trigger Cycles 0 Analogue Ch 00011111100001000 Logic Input Trigger 00000000000000 Relay Output Trigger 000000000000000 Records Stored 0 End of Report Service M anual R5942B LG PG111 Chapter 6 Page 77 of 91 8 2 Protection settings LGPG RELAY lt Not Defined gt Serial Number 0000000 Printed on Tue 1994 Aug 23 16 34 17 PROTECTION SETTINGS Generator Differential 87G Generator Differential Enabled Isl O 10 A Kl 0 Is2 1 20 A K2 150 Earth Fault Protection 51N Stator Earth Fault Enabled 51N gt Low Set Characteristic Definite Time Ie gt 385mA t gt O 1l s tRESET Os 51N gt gt High Set Enabled Te gt gt 275mA t gt gt Os 1 is 59
40. 19 lt min Condition Xg Xd s Eg Es 0 8 Figure 27 Field failure protection function characteristics small co generator for co generation schemes and might also be the case for some fairly large utility generation schemes connected to a densely interconnected transmission system The dynamic impedance of the generator during pole slipping X should lie between the average value of the direct and quadrature axis transient reactance s X and X and the average value of the direct quadrature axis synchronous reactance s X and X_ However neither extreme would actually be reached During low slip periods of a pole slip cycle the synchronous reactance s would apply whereas the transient impedance s would apply during periods of relatively high slip Service M anual R5942B LG PG111 Chapter 3 Page 67 of 75 Figures 27 and 28 illustrate how the impedance seen at the generator protection relaying point may vary during pole lipping for a relatively small co generator directly connected to a relatively strong distribution power system The two figures consider extremes of generator system emf ratios and the two extreme values of generator impedance discussed above Figures 29 and 30 are similar illustrations for a relatively large utility generator connected to a strong interconnected transmission system It should be noted that the behaviour of a generator during pole slipping may be further complicated by interven
41. 2 15 3 15 4 amp 15 5 Field failure settings Service M anual LG PG111 R5942B Chapter 6 Page 61 of 91 7 17 Scheme logic Table 36 Item Front Panel Remote Access 16 0 aes LOGIC Scheme Logic 16 1 Latch O P Latch Output 000000000000000 000000000000000 16 2 Flt Rec Trig Fault Record Trigger 100000000000000 100000000000000 16 3 Alm Rec Trig Alarm Record Trigger 111111111111111 111111111111111 16 4 Input AND Matrix 16 5 Input Matrix IN 0 10000000000000000000000000000000 Word 0 gt 16 36 Input Matrix IN31 00000000000000000000000000000000 Word 31 gt 16 37 Output OR Matrix 116 39 Output Matrix OUT 0 100000000000001 Word 0 gt 16 69 Output Matrix OUT31 000000000000000 Word 31 gt The LGPG111 s Scheme Logic Section of its menu Contains all the settings for the scheme logic plus settings for specifying which outputs are latch ed or self reset which outputs trigger alarm events and which outputs trigger a trip event 16 1 Latched output specification Allows any of the fifteen outputs to be specified as latching with manual reset A 1 in a bit position selects the output as latching otherwise it will be self reset This setting is password protected N ote thatin order for the latched outputs to be resettable their operation triggers an alarm record the alarm trigger is the logical O
42. 2 201 R 2R R W here Minimum current transformer kneepoint voltage for through fault sta bility Relay rated current R Resistance of current transformer secondary winding Q R Resistance of a single lead from relay to current transformer Q R Resistance of any other protective relays sharing the current transformer Q For class X current transformers the excitation current at the calculated kneepoint voltage requirement should be less than 1 01 For IEC standard protection class current transformers it should be ensured that class 5P are used Sensitive directional earth fault protection function residual current input Line current transformers W ith reference to section 2 5 the sensitive directional earth fault input current transformer could be driven by three residually connected line current transformers Ithas been assumed that the sensitive directional earth fault protection function will only be applied when the stator earth fault current is limited to the stator winding rated current or less Also assumed is that the maximum X R ratio for the impedance to a bus earth fault will be no greater than 5 The required minimum kneepoint voltage will therefore be V gt 61 R 2R R W here V Minimum current transformer kneepoint voltage for through fault sta bility Relay rated current R Resistance of current transformer secondary winding Q R Resistance of a single lead from relay
43. 3 For the different voltage vector rotation setting inject the voltage as follows for each phase Service M anual R5942C LG PG111 Chapter 8 Page 39 of 66 Voltage Phase A Phase B Phase C Rotation Inject Inject Inject Setting None 0 5x K 1 I gt 0 5x Vsl Vs2 0 5x K 1 I gt 0 5x Vsl Vs2 0 5x K 1 I gt 0 5x Vs1 Vs2 into into Va into Ip into Vp into into Vea Yd O 5x K 1 I gt 0 433x Vsl V 0 5x K 1 gt 0 433x Vsl V 0 5x K 1 I gt 0 433x Vs1 V into la s2 into Vab into Ib s2 into Vab into le s2 into Vbc N ote For Yd rotation the 0 433 value in the in above procedure is derived from the following Phase A Va Va 1 3 where V 4V_ V Phase B V Va 1 V3 Phase C V aV 2 43 where V V V Inject the specified current and voltage to check the pick up and drop off values The Protection O peration Summary Section of the relay s menu can be used to determine this without the need to wait for timer operation Stop the current injection only Accept and reset all alarms pick up value 0 5x K 1 I gt setting with a 5 tolerance drop off value 0 95x 0 5x K 1 I gt setting with a 5 tolerance Repeat the tests for phases B and C Measurement of operating time characteristic Inject a voltage of 1 2 x Vs1 and inject a current of 2 x I gt Amps to obtain the relay s operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check
44. 51N 31 51N Block for phase fault Figure 31 Application of LGPG111 51V and 51N timer inhibits for discrimination with feeder protection Stator earth fault timer inhibit 51N timer inhibit This input is used to inhibit the timer of the stator earth fault function Either the low set or high set element or both can be inhibited Its application is the same as that of the overcurrent timer inhibit input as shown in Figure 31 Service M anual R5942B LG PG 111 7 4 7 5 Chapter 4 Page 42 of 50 Alternative setting group selection setting group select Inputs 3 and 4 are used to select the alternative setting group Both inputs need to be energised for the selection to be effective If only one input is energised then the LG PG111 will assume that there is a failure and will raise an alarm The group selec tion logic is shown in Table 3 Logic Input 3 Logic Input 4 Group Selected 0 0 Group 1 1 1 Group 2 0 1 Indeterminate states active 1 0 setting group remains unchanged Table 3 Setting Group Select logic inputs Real time clock synchronisation clock sync The Clock Sync input is used to feed a time aligned pulse signal to the relay This is used to synchronise the internal real time clock The feature can be disabled or it can be set to synchronise the clock every 30s or every 1 5 10 15 30 or 60 minutes If the Clock Sync setting is set to 30 minutes for example then activation of t
45. 74 Service M anual R5942B LG PG111 Chapter 3 1 1 1 Page 5 of 75 INTRODUCTION Generating plant A generator forms the electromechanical stage of an overall energy conversion process that results in the production of electrical power Except for very special circumstances e g for some types of railway locomotives AC electrical power is normally produced A reciprocating engine or one of many forms of turbine acts as a prime mover to provide the rotary mechanical input to an alternator W hilst induction machines are sometimes used for generation in parallel with a main public supply system e g in the case of some mini hydro schemes the synchronous machine is normally used for production of AC electrical power The LGPG111 caters for the protection requirements of synchronous generators The term generator is generally used to describe the complete energy conversion system whilst the term alternator is sometimes used as a more specific description of the electromechanical conversion unit The running speed of a prime mover which is ultimately dependent on the original source of energy for the conversion process greatly influences the mechanical and electrical design aspects of the generating system In the case of a very high speed prime mover for instance a reduction gearbox would be used to transmit mechanical power to a 2 pole cylindrical rotor alternator In the case of a very slow speed prime mover a salie
46. Application to an indirectly connected generator For indirectly connected applications illustrated in Figure 5 the time delayed earth fault protection function may be employed in one of two ways 1 To measure earth fault current indirectly via a CT in the secondary circuit of a distribution transformer earthing arrangement 2 To measure earth fault directly via a CT in the generator winding earth con nection Service M anual R5942B LG PG111 Chapter 3 Page 21 of 75 W ith the first mode of application the current operated protection function 51N may be used in conjunction with voltage operated protection function 59N measuring the distribution transformer secondary voltage This is a complementary arrangement where the voltage operated protection function 59N is able to operate in the event of an open circuited loading resistor and the current operated protection function 51N is able to operate in the event of a shortcircuited resistor The second mode of application would be used for cases of direct resistive earthing For distribution transformer earthing this mode offers the advantage of being able to respond to an earth fault condition that leads to a flashover of the distribution transformer primary connections Such a primary short circuit would render protection on the secondary side of the transformer inoperative and it would also result in a very high and damaging primary earth fault current The high earth fault
47. Channel 11100000011111000 Channel gt 19 5 Logic I P Trig Logic Input Trig 00000000000000 00000000000000 19 6 Relay O P Trig Relay Output Trig 111000000001000 111000000001000 19 7 Records Stored Records Stored 0 0 a 19 8 Clear All Clear All Records No Records Page 67 of 91 Table 42 The LGPG111 s Disturbance recorder Section of its menu Configuration settings for the disturbance waveform recorder 19 1 Disturbance recorder status The status of the recorder Can be Stopped Triggered or Running The disturbance recorder is normally in the running state and is ready to be triggered W hen a trigger occurs the recorder is in the triggered state for the duration of the post trigger data capture After the first recording the recorder automatically returns to the running state ready for a second trigger otherwise it enters the stopped state The stopped state is automatically cleared back to the running state when the remote system extracts one of the two disturbance records Alternatively both records can be erased by activating the Clear All Records cell 19 8 and the recorder will return to the running state The recorder can be manually triggered by manually changing this cell to the triggered state It is not possible to enter the stopped or running states manually The relay will rejecta manual trigger if it is currently processing a trigg
48. DT Charact le gt t gt tRESET 51N gt gt High set le gt gt t gt Enabled Disabled Enabled Disabled Enabled Disabled SI DT Enabled Disabled 59N Neutral Disp Enabled Disabled Ve gt tl t2 t2 RESET Enabled Disabled 67N Sensitive DEF Enabled Disabled Iresidual gt RCA Vep gt lep gt Enabled Disabled Voltage Dependent Overcurrent 51V O vercurrent Function Vs1 Vs2 Vs Enabled Disabled Enabled Disabled Service M anual R5942B Chapter 9 LGPG111 Page 47 of 52 K Characteristic gt t gt tRESET SI DT SI DT Service M anual LGPG111 Power Protection R5942B Chapter 9 Page 48 of 52 Compensation Angle 32R Reverse Power P lt t tDO 32L Low Forward P lt t tDO Enabled Disabled Enabled Disabled Enabled Disabled Enabled Disabled Frequency Protection 81U 1 Under Freq Fl lt tl 81U 2 Under Freq F2 lt t2 810 O ver Freq F gt t Voltage Protection 27 Under Voltage V lt t 59 Over Voltage y gt t gt V gt gt t gt Enabled Enabled Enabled Enabled Enabled Disabled Disabled Disabled Disabled Disabled Enabled Disabled Enabled Disa
49. FUNCTIONS Because of the numerical nature of its design the LGPG111 is able to provide the following non protection functions to complement its functionality 1 Measurements Event and fault recording Alarm indication Disturbance recording Real time clock Test facilities Print functions 8 Self monitoring The following Sections describe each function in detail YH OI BW DN Measurements The rms magnitudes of all the seventeen analogue inputs are available as measurement values They are the three phase voltages and currents the neutral voltage and current the residual current the differential currents and the bias currents O ther derived quantities are also available They are the negative phase sequence current the A phase active and reactive power the phase angle between I from the l input and 7 the mean bias currents and the power system frequency a sensitive All measurements can be displayed in either primary or secondary quantities The selection is done through the Display Value setting in the Auxiliary Functions Section of the menu If primary quantity is selected as the display quantity then all the measurement displays will be multiplied according to the system CT and VT ratio settings These settings are located in the Transformer Ratios Section of the menu Event recording The LGPG 111 is capable of storing a maximum of 100 event records in its non volatile memory area Every
50. Fault Record Trigger setting in the Scheme Logic Section specifies which outputs are to considered as trips and hence also to produce a fault record For example in Figure 1 when output relay R15 operates the red trip LED will operate and a fault record is generated Operation of the other output relays will not cause the red Trip LED to turn on The yellow Alarm LED on the relay can be operated by one or more of the output relays The Alarm Record Trigger setting in the Scheme Logic Section specifies which outputs are to considered as Alarms For example the alarm record trigger in Figure 1 generates an alarm whenever output relay R1 R2 and R3 operate O peration of the other output relays will not cause the yellow Alarm LED to turn on The Alarm LED will also illuminate whenever there is a trip causing the red Trip LED to illuminate or when an output operates which has been specified as latching For example if the alarm record trigger is removed from relay R1 in Figure 1 an alarm will still be generated since R1 is specified as a latched output N ew alarms are signified by a flashing yellow Alarm LED and a flashing ALARM message on the relay s display There are two types of alarms one is a protection alarm and indicates which protection function operated The other is a relay output alarm and indicates which output relay operated For example ALARM Protection 87G Gen Diff A isa protection alarm which indicates t
51. I value is well above the threshold W hen high values of K are selected and the negative phase sequence currents measured are near to the threshold the operating time as determined by the characteristic may be too slow In this case a maximum time setting t is available to provide a safe trip time W hen I is above the nominal current the operating time may become too fast and may cause incorrect discrimination against other overcurrent relays under fault conditions The inverse characteristic should then change to a definite time characteristic which is defined by the minimum time setting tyy To provide integration of successive when the duration of each I input is insufficient to cause tripping an exponential reset characteristic is provided Enable the 46 N egative Phase Sequence protection only If necessary change the scheme logic input matrix so that only the 46 will cause the output relays to operate M easurement checks Inject rated current into the and inputs so that phases A and B are in antiphase terminals A11 A13 with Al2 and A14 linked Record the current injected and the negative phase sequence current 12 measured by the relay The measured 12 should be 0 577 times the injected current allowing 5 tolerance Repeat the above test but inject into the and inputs terminals A13 A15 linking A14 to A16 Characteristic and operating time for 46 gt N PS alarm If the 46 gt N PS Alarm i
52. July 1995 Dave Banham Styles Publicity Service M anual R5942A LG PG111 Chapter 2 Page 3 of 6 Contents 1 GEN ERAL CO N SIDERATION S 4 K Receipt of product 4 I2 Electrostatic discharge ESD 4 2 HAN DUNG OF ELECTRONIC EQUIPMENT 4 3 UN PACKING AND IN STA LUN G 5 3 1 M ounting 5 3 1 1 Rack mounting 5 3 1 2 Panel mounting 5 3 2 Auxiliary power supplies 6 4 STO RAGE 6 Service M anual R5942A LG PG 111 1 1 1 1 2 Chapter 2 Page 4 of 6 GENERAL CONSIDERATIONS Receipt of product Although the product is generally of robust construction careful treatment is required prior to installation on site Upon receipt the product should be examined immediately to ensure no damage has been sustained in transit If damage has been sustained during transit a claim should be made to the transport contractor and a ALSTOM T amp D Protection amp Control Ltd representative should be promptly notified Products that are supplied unmounted and not intended for immediate installation should be returned to their protective polythene bags Electrostatic discharge ESD The product uses components that are sensitive to electrostatic discharges The electronic circuits are well protected by the metal case and the internal modules should not be withdrawn unnecessarily W hen handling modules care should be taken to avoid contact with components and electrical connections If removed from the case for storage the mod
53. LED turns on and the yellow Alarm LED flashes when relay operates Check ALARM Protection 46 gt gt NPS appears on the relay ignore other alarms Reset all alarms Measurement of t operating time Service M anual R5942C LG PG111 Chapter 8 7 9 5 Page 47 of 66 To check tp inject 2 5 X yiy Xin into the and inputs so that phases A and B are in anti phase terminals A11 A13 with A12 and A14 linked to obtain a fast operating time K andt are the relay settings Make sure the current injected does not exceed the CT s continuous thermal rating of 4xIn Record the operating time obtained and compare with the t setting O perating time tyw with a 5 tolerance 10 to 40mS M easurement of t x operating time Firstly calculate the expected tripping time for an injected current of 1 2 x 12 gt gt using the following equation 1186 x K 2 x 12 gt gt where 12 gt gt and K are the relay settings If the calculated time is less than the t setting itis not possible to measure the t operating time If the calculated time is greater than the t setting then inject 3 6 x 12 gt gt Amps into the input terminals A11 A12 and at the same time start a stop watch to measure the relay s operating time Record the operating time obtained and compare with the setting O perating time t with a 5 tolerance Checks for 46 gt gt N PS thermal trip reset time To perform this t
54. Logic Group 2 setting area Table 51 Non volatile EEPROM memory errors Service M anual LG PG 11 9309 ALAR 60 VB Comp ALARM FE 32L ALARM FE 32R ALARM F 51V ALARI 1 R5942B Chapter 6 Page 90 of 91 Protection operation alarm messages This type of alarm is caused by the operation of the fault record trigger alarm record trigger or the operation of latched outputs Display Protection O peration Pr LEE RP OC A SPro CEC CEC tion Voltage Balance due to failure of the comparison VT s Voltage Balance due to failure of the protection VT s Field Failure Sensitive Directional Earth Fault Timer 2 element of N eutral Displacement Timer 1 element of N eutral Displacement High set element of Stator Earth Fault Low set element of Stator Earth Fault Trip element of Negative Phase Sequence Alarm element of N egative Phase Sequence O ver Voltage The field gt is the element information with gt mean ing low set and gt gt high set Under Voltage Under Frequency 2 Under Frequency 1 Low Forward Power Reverse Power Voltage Dependent O vercurrent The field A is the phase information tion 87G Gen Diff A Generator Differential The field A is the phase information Table 52 Protection operation Alarm messages Service M anual LG PG111 9
55. N O O O HN a WM 10 10 11 11 11 11 11 12 12 12 13 13 13 13 13 13 14 14 14 15 16 16 16 Service M anual LG PG111 Del 6 6 1 6 1 1 6 2 6 2 1 al el 6 2 1 2 6 2 1 3 6 2 1 4 6 3 6 3 1 6 4 6 4 1 6 4 2 6 4 3 6 5 Front panel user interface REPLACEM EN T MODULE HARDWARE CON FIG URATIO N Relay output module G M0032 Address decode M icrocomputer amp serial communications module GM0099 M icroprocessor board M emory selection Watchdog Timer Interrupt amp DMA Select RS232 Factory Test Interface Select Status Input M odule GM0022 GM0111 Address Decode Analogue and status input module Address Decode Interrupt amp DMA Select Calibration Front panel operator interface R5942B Chapter 5 Page 4 of 23 16 18 19 20 20 20 20 20 20 20 20 20 22 22 22 22 23 Service M anual LG PG111 1 INTRODUCTION R5942B Chapter 5 Page 5 of 23 The LG PG111 is constructed using M4 multi modular hardware A number of identification systems are used to define a particular relay variant the components within that variant and also its application A brief description of these numbering systems is given within this Chapter A description of the relay hardware is then given followed by functional details of each module which includes information on the input and output connections The position of movable links within the modules is listed at the end of t
56. O O O 1 1 1 Latch outputs Fault record trigger Alarm trigger Figure 31 LGPG111 factory scheme logic settings The standard factory settings are designed to provide a basic protection scheme that should be suitable for most installations By making minor modifications and additions to the standard factory scheme logic settings the LGPG111 can be made to meet the Service M anual R5942B LG PG111 Chapter 3 5 1 5 1 1 Page 71 of 75 individual application tripping requirements To complete the application of the LG PG 111 the protection function parameters should be setto values appropriate for the generator being protected The relay s standard scheme logic has been configured with all of the protection functions except for the low forward power function assigned to relay outputs The low forward power function has not been included because apart from applications with steam turbines itis not normally used The protection functions that operate for generator faults or provide back up for downstream protection have relay outputs assigned for tripping the generator circuit breaker field and prime mover The protection functions for detection of abnormal operating conditions have relay outputs assigned for tripping the generator CB and the excitation field Itis not necessary to trip the prime mover because abnormal conditions can usually be resolved quickly It should be noted that each active protect
57. PS tMIN 46 gt gt NPS Trip tMIN hs nas Ea PS tMAX 46 gt gt NPS Trip tMAX 03 saa k Field Failure 40 Field Failure 03 21 28 o VB Prot 60 Voltage Balance Prot 03 21 29 Ee VB Comp 60 Voltage Balance Comp 0 Table 48 The LGPG111 s Protection O peration Summary Section of its menu Provides protection operation status indications as a percentage time to trip O nly cells with other usage are documented below as the rest are self explanatory 21 1 Date amp time This cell only appears on the remote access menu W hen the remote system reads this section it captures a snapshot of the protection operation summary this cell provides a time stamp indicating when the data was captured This is nota problem for the front panel since the display is updated approximately every 500ms 21 2 amp 21 11 Sub itle cells These two cells only appear on the remote access menu the three phase information for the differential and overcurrent respectively appear indented below them 21 24 NPS Trip thermal This cell does not indicate percentage time to trip but percentage thermal withstand Service M anual R5942B LG PG111 Chapter 6 8 8 1 Page 75 of 91 PRINT REPORT EXAMPLES The following are examples of the various reports which the LGPG111 can printona parallel printer connected to its parallel port The reports are generated by the print cell in the Auxiliary Functions Section The
58. R of the latched output and alarm trigger settings The bits are summarised in Table 37 Service M anual R5942B LG PG111 Chapter 6 Page 62 of 91 Bt Name 0 Relay 1 Relay 2 2 Relay3 3 Relay4 4 Relay5 5 Relay 6 6 Relay 7 Relay 8 8 Relay 9 9 Relay 10 10 Relay 11 11 Relay 12 12 Relay 13 13 Relay 14 14 Relay 15 Table 37 Bit flag assignment read right to left of the fifteen scheme configurable outputs The names can be changed in the Input Output Labels Section 16 2 Fault record Trigger Specifies which outputs are to generate a fault record A 1 in a bit position causes the operation of that output to generate a fault record Generation of a fault record also causes the LGPG111 to indicate a trip on the front panel and in the remote access status information This setting is password protected The bits are summarised in Table 37 16 3 Alarm record trigger Specifies which outputs generate an alarm record A 1 ina bit position causes the operation of that output to generate an alarm record Generation of an alarm record also causes the LGPG111 to indicate an alarm on the front panel and in the remote access status information This setting is password protected The bits are summarised in Table 37 16 4 Input AND matrix A sub title cell for the remote system only all the scheme logic input AN D matrix sett
59. Salient pole Indirectly cooled 0 08 20 Directly cooled inner cooled stator 0 05 15 and or field Cylindrical rotor synchronous Indirectly cooled rotor Air cooled 0 1 15 Hydrogen cooled 0 1 10 Directly cooled inner cooled rotor lt 350MVA 0 08 8 gt 350 lt 900MVA K gt 900 lt 1250MVA 5 gt 1250 lt 1600MVA 0 05 5 For these generators the value of 1 is calculated as follows lz s S 350 ln 3 x 104 For these generators the value of l 1 tis calculated as follows 2 B t 8 0 00545 S 350 n Where S is the rated power in MVA Table 3 IEC6034 1 Minimum negative sequence current withstand levels For high levels of negative phase sequence current eddy current heating can be considerably in excess of the heat dissipation rate Thus virtually all the heat acquired during the period of unbalance will be retained within the rotor W ith this assumption the temperature attained within any critical rotor component will be dependent on the duration of the unbalance t seconds and the level of negative phase sequence current I per unit and is proportional to t Synchronous generators are assigned a per unit t thermal capacity constant K to define their shorttime negative phase sequence current withstand ability see third column of Table 3 Various rotor components may have differing short time thermal capacities and the most critical lowest value of 7t
60. The LGPG111 is a sophisticated generator protection relay and includes many protective functions and operating features You are strongly recommended to read these instructions and to allow sufficient time to familiarize yourself with the relay its user interface and the rest of this service manual before commencing with the commissioning tests 1 GENERAL NOTES Before commissioning an LGPG111 you should understand the following aspects The relay s scheme logic see chapter 4 The user interface see chapter 6 Although the settings can be entered manually there can be considerable time savings if a portable PC is available with suitable Courier based access software installed This is easier to use and greatly facilitates entering settings which can then be saved for future reference Instructions are provided with the Courier based access software See chapter 6 for a basic overview In these commissioning instructions specific operations regarding the user interface are given for the relay s front panel only Testing the remote access feature of the LGPG111 is not covered by these commissioning instructions Before commencing the commissioning of the relay the notes in section 5 1 should be read The recommended commissioning procedure is as follows Section 3 Commissioning preliminaries Section 4 Auxiliary power supply tests Section 5 Secondary injection tests preliminaries The commissioning engineer along with
61. The instantaneous sensitive directional earth fault protection function is provided with a dedicated single phase CT input for the operating current This input could accept the residual current from three line CT s or current from a dedicated core balance CT An adjustable operating current threshold is provided Iresidual gt The polarising signal for the directional decision is either a voltage applied to the neutral voltage VT input or a current signal applied to the stator earth fault current input Independent polarising voltage and polarising current threshold settings Vep gt lep gt are provided for this protection function O ne of these polarising signal thresholds must be exceeded to allow operation of the sensitive directional earth fault protection function W here the voltage threshold Vep gt is exceeded the current polarising signal is ignored A characteristic angle setting RCA is provided for the directional element This determines the required angle between the polarising voltage and the operating current signals for optimum directional element response The required angle between the polarising current and the operating current signals for optimum directional element response is zero degrees This protection function would only be applied in cases of parallel generators being directly connected to a busbar see Figure 3 where the generator differential unit type protection function does not have adequate sensitivity
62. Under frequency and under voltage inhibit Overcurrent timer inhibit Stator earth fault timer inhibit and 4 Alternative setting group selection Real time clock synchronisation U1 WIN rFR o Table 2 Dedicated logic input assignment Inputs 6 to 13 are connected to the scheme logic They can be used to operate relay outputs directly or for blocking and interlocking with other protection functions Inputs 6 to 9 are provided with inverted signals for blocking applications All the logic inputs are activated by applying the specified auxiliary voltage Vx 2 across their input terminals This produces a nominal 10mA current in the optical isolation circuitry If a particular function is not required the corresponding logic input may be left unconnected or shorted The logic inputs are sampled at 12 samples per electrical cycle the same rate as the analogue inputs A software filter ensures that the input states are consistent for 6 samples before an internal state change occurs This is to prevent inadvertent pickup caused by capacitive coupling from the power system signals Therefore for an input to be activated it needs to be energised for a duration longer than half of the electri cal cycle Service M anual R5942B LG PG111 Chapter 4 7 1 7 2 7 3 Page 41 of 50 Under frequency amp under voltage inhibit 27 amp 81U inhibit This input is used to inhibit the under frequency and the under voltage p
63. _ d Press SET To Prn Print Print 10 Event Records 10 Event Records Press SET To Prn Print Print 25 Event Records 25 Event Records Press SET To Prn Print Print All Event Records All Event Record _ S Table 13 States of the Print cell Second setting group Controls whether the LG PG 111 has an alternative second setting group The cell can be either Disabled or Enabled In the disabled state the active setting group and select setting group cells are hidden Additionally the settings for the second setting group are hidden in the menu and the group 1 identifiers removed from the remaining visible settings If group 2 settings are enabled when the disabled state is selected group 1 primary settings are selected and an event generated In the enabled state the active setting group and select setting group cells are visible Additionally the settings for the second setting group are visible in the menu Cells belonging to the setting groups are identified by their group number If the group selection is set to logic input and the inputs are energised to select group 2 group 2 is selected and an event generated This cell is password protected Select setting group Controls the selection method for the active setting group The cell can be either Logic Input or Menu The logic input setting allows the active group to be controlled by a pair of Optically isolated logic inputs In this mode the activ
64. a database System data Enabled Measurements Is1 0 05A Records K1 0 Differential Is2 1 2A Earth fault K2 150 Overcurrent Field failure o o The database has been organised into a menu ike book with several sections Each section has a title 1Some times the front panel user interface is called the loca access Service M anual R5942B LG PG 111 Chapter 6 Page 6 of 91 A user can browse over the section titles in a similar fashion to reading a book s contents page Except here the contents of the desired section can be turned to directly by selection of the desired section heading The remote user interface accesses the information one section ata time The front panel user interface navigates around the individual items of information called cells with 4 arrow keys Remote System Front Panel One section at a time One cell at a time One line per cell Two line display Voltage Dependent Overcurrent 1 7 51V Overcurrent Disabled ep 91 Overcurrent Function Voltage Controlled 1 Disabled Vs 33 V K 0 25 Characteristic Standard Inverse ae 51V Overcurrent I gt 1 00A 1 Char SI TMS 1 00 tRESET Os e o o o Figure 2 Illustration of the differences between the two access systems There are some minor differences in display formats between the two interfaces The front panel s display is limited to 2 lines of 16 characters whilst the remote interface is assume
65. a large number of protec tion functions combined to drive a few common trip outputs Some blocking and interlocking logic may also be required To accommodate different generator applica tions the scheme logic design must be flexible and configurable The scheme logic provided by the LGPG111 is in the form of logic arrays with an architecture commonly found in programmable logic array devices The logic arrays consist of an AN D OR structure shown in Figure 28 Service M anual R5942B LG PG 111 Chapter 4 Page 36 of 50 From protection elements and logic inputs O utput matrix Input matrix To output relays Figure 28 Scheme logic block diagram There are 32 inputs to the scheme logic nineteen from the protection functions eight from the logic inputs and a selection of inverted inputs which allow blocking logic to be created The AN D function combines two or more inputs to provide blocking or interlocking logic or simply acts as a through connection for one input The OR function allows one or more of the AN D function outputs to control each output relay Up to thirty two input combinations can be accommodated at any one time and the scheme logic controls a total of fifteen output relays To implement the scheme logic settings each logic line is represented by two binary words one for the input AN D matrix and one for the output O R matrix Each interSection in the matrices is represented by a bit within each word Thus the i
66. adjustable delay on reset of the trip timer tDO This time delay can be set to ovoid delayed tripping that might arise as a result of cyclic operation of the impedance measuring element during the period of pole slipping following loss of excitation Some care would need to be exercised in setting this timer since it could make the field failure protection function more likely to give an unwanted trip in the case of stable power swinging The trip time delay should be increased by the setting of the reset time delay Service M anual R5942B LG PG111 Chapter 3 2 10 Page 51 of 75 The delay on reset of the trip timer tDO might also be set to allow the field failure protection function to be used for detecting pole slipping of the generator when excitation is not fully lost e g following time delayed clearance of a nearby power system fault by delayed protection This subject will be discussed in more detail in Section 3 5 Under voltage protection function 27 Summary O perates when the three phase voltages fall below the common set point An adjustable timer is available Can be interlocked with the field failure protection to prevent its operation during stable power swings see Section 2 9 Can be used to initiate dead machine protection see Section 3 1 Can detect failure of the AVR or system faults which have failed to be cleared by other means Prevents damage to any connected loads which could oc
67. an offset mho characteristic No Trip Xb Enable the 40 Field Failure protection only If necessary change the scheme logic input matrix so that only the 40 Field Failure will cause the output relays to operate There is no need to change the input matrix for blocking by the Voltage Balance element M easurement checks The Field Failure element uses and V to calculate impedance V is derived from the V input by rotating by 30 and dividing by v3 Inject rated voltage into terminals B25 B26 and rated current into terminals A9 and A12 with A10 and A11 linked the inputA9 A10 I is used in order to obtain a phase angle measurement Adjust the phase difference between the voltage and the current until the phase angle meter reads leading V by 60 Record the current and voltage measured by the relay allowing 3 tolerance Check the Phase Angle Aph measured by the relay The phase angle between and V measured by the relay should be 90 allowing 5 tolerance Reset all alarms Service M anual R5942C LG PG 111 1 4 2 Chapter 8 Page 28 of 66 Characteristic and operating time Record the field failure protection settings Xa Xb tand tDO The set values for Xa and Xb are given in terms of resistance To avoid damage to the relay ensure that the current injected is not increased above 3 x rated current The allowable tolerance for Xa and Xb is 5 Measurement of Xa Xb The expect
68. analogue input circuits the communication hardware and the group select logic inputs During background processing all the memory components in the main processor module including data stored in the EEPROM are checked continuously Depending upon the severity of a failure the relay reacts in the following fashion 1 Minor error A minor error is such that it does not cause maloperation of the relay The protection will be allowed to continue and corrective action will be taken See Table 5 for the errors that fall in this category 4CRC is an acronym for cyclic redundan y code In the relay the CRC checksum is calculated based on the CRC 16 polynomial which is X16 X15 X2 1 The implementation of the polynomial is based on a word wise on the fly method Service M anual R5942B LG PG111 Chapter 4 Page 49 of 50 2 Fatal error An error is fatal when it could cause maloperation of the relay Under such conditions the protection will be disabled O ther functions such as remote communications and front panel user interface will be available if possible See Table 6 for a list of the fatal errors 3 Lockout error The consequence of a lock out error is such that the relay is unable to continue processing Under such circumstances the relay will not be able to record events and raise alarms Most errors detected by the power on diagnostics are categorised as lock out errors The cause of the error is displayed on the front pan
69. ata much higher level of slip perhaps 5 above synchronous speed W hen this happens the machine will draw a very high reactive current from the power system and a stator winding current as high as 2 0 p u may be reached In addition to stator winding thermal problems arising during super synchronous operation the slip frequency rotor currents could lead to rotor core or winding damage if the condition is sustained If after an excitation failure the generator continues to produce active power in an induction generation mode with a small level of slip there would be no great urgency to disconnect the machine The condition could probably be sustained for many minutes without rotor damage being incurred W ith the typical settings applied to the field failure impedance protection such an operating condition might not be detected by the protection It would be necessary for an operator to manually intervene to either re establish the excitation or to shut down the generator Such action could be taken if the remote instrumentation capability of the LGPG111 indicates that the generator is operating atan abnormally low leading power factor Service M anual R5942B LG PG111 Chapter 3 Page 49 of 75 loss of field locus Figure 17 Field failure protection function characteristic with typical machine impedance locus W here a generator stabilises ata high level of slip following excitation failure the reverse inductive impedance seen at the
70. available to provide a safe trip time Conversely when l is considerably above the 12 gt gt threshold the operating time may become too fast and cause incorrect discrimination with other overcurrent relays under fault conditions To counter this the inverse characteristic changes into a defi nite minimum time characteristic The change over point is defined by the minimum time setting tM IN The characteristic is as shown in Figure 18 Service M anual R5942B LGPG111 Chapter 4 3 8 3 8 1 3 8 2 Page 29 of 50 Figure 18 N egative Phase Sequence Thermal characteristic Field failure 40 G eneral description The field failure protection function consists of an impedance measuring element with an offset mho characteristic The centre of the mho circle lies on the negative reactive axis of the impedance plane The measuring input quantities are I and V The V quantity is derived from the V input phase shifted by 30 i e Va wx 12 30 An integrating timing feature is provided for this function The logic of the integrating timing is discussed in Section 3 13 Settings And Characteristic The settings provided by this function are as follows Xa Negative reactive offset of the circle from the origin of the impedance plane Xb Diameter of the circle t Timer setting tDO Delayed drop off timer for integrated timing The characteristic is illustrated in Figure 19 Service M an
71. be accompanied by throttle or valve closure There is always a risk however that the throttle valves may not close fully and that machine over speed will result when electrical loading is removed W ith large high speed steam turbo alternator sets an apparently small over speed could result in machine damage or wreckage as well as a threat to human safety Failure of a steam valve to fully close during a shut down is an obvious risk This over speed risk could be addressed by using duplicate valves in series Even where valves etc do close fully there will be some lag in dissipating all the Low foward power 32L RLI5 RL14 Figure 16 Low Forward Power Interlocking Of Non urgent Tripping Functions energy within a prime mover especially in the event of a shutdown from fullload Some types of plant are very prone to over speed following rejection of fulldoad but have a good over speed tolerance e g slow speed hydro generators Large turbo alternators with slender low inertia rotor designs do not have a high over speed tolerance and trapped steam in the turbine downstream of a valve that has just closed can rapidly lead to over speed To reduce the risk of over speed damage to such sets itis sometimes chosen to interlock non urgent tripping of the generator breaker and the excitation system with a low forward power check The delay in electrical tripping until prime mover energy has been completely absorbed by the power syste
72. before plant damage or unprotected system load damage could occur Under frequency running at nominal voltage will result in some over fluxing of a generator and its associated electrical plant which needs to be borne in mind However the more critical considerations would be in relation to blade stresses being incurred with high speed turbine generators especially steam driven sets W hen running away from nominal frequency abnormal blade resonance s can be set up which if prolonged could lead to turbine disc component fractures Such effects can be accumulative and so operation at frequencies away from nominal should be limited as much as possible to avoid the need for early plant inspections overhaul Under frequency running is most difficult to contend with since there is little action that can be taken at the generating station in the event of load under shedding other than to shut the generator down The LG PG111 under frequency protection function should be set to co ordinate with automatic system load shedding so that generator tripping will not occur in the event of successful shedding following a system overload The protection function should also be setso that declared frequency time limits for the generating set are not infringed A 10 under frequency condition should be continuously sustainable The two stages of under frequency protection offered by the LGPG111 could be set up as illustrated in Figure 18 to co ordinate with
73. consideration might have to be given to the reset time delay setting tDC required in such circumstances During pole slipping any operation of the LGPG111 field failure protection function Service M anual R5942B LG PG 111 Chapter 3 Page 68 of 75 will be cyclic and so it would be necessary to set the reset time delay tDO to be longer than the time for which the impedance seen will cyclically lie outside the field failure characteristic A typical delay setting might be 0 6s to cater adequately for cover slip frequencies in excess of 2Hz W hen the timer tDO is set the field failure trip time delay t must be increased by the setting of tDO Base MVA 152 35 MVA Xd 195 Xd 18 1 Xt 17 7 Xs 1 83 17 4kA at 275kV Eg Es 2 8 gt max R Eg Es 1 2 e Diameter Xd Eg Es 1 0 Eg Es 0 8 Case 152 35 MVA GT Condition Xg Xd Eg Es 0 19 lt min Figure 29 Field failure protection function characteristics large generator Sometimes pole slipping protection must be guaranteed especially in the case of a larger utility generator connected to a relatively weak transmission system Here the described means of providing pole slipping protection might only be fully effective if the pole slipping impedance measuring element uses voltage signals derived from the HV side of the step up transformer In such applications and where fast tripping is required or where the pole slipping response of field
74. data was captured This is nota problem for the front panel since the display is updated approximately every 500ms amp 5 4 Differential current The magnitudes of the differential currents Service M anual R5942B LG PG111 Chapter 6 Page 41 of 91 5 5 5 6 amp 5 7 Bias currents The magnitudes of the bias currents 5 8 5 9 amp 5 10 Mean bias currents The derived magnitude of the mean bias current Ordinarily a mean bias quantity is derived from two bias measurements The LG PG 111 has only one bias measurement per phase and derives the second from the differential and bias measurements Bias lp hie Bias Diff z 2 5 11 Sensitive A phase current M eanBias The magnitude of the A phase high sensitivity current input This measurement is used for the calculation of power and phase angle 5 12 amp 5 13 Comparison voltages The magnitudes of the comparison voltage inputs 5 14 Frequency tracking input This cell indicates the input being used by the frequency tracking The LG PG111 can frequency track from one of three inputs Vp V or l W hen there are no signals on these inputs the frequency tracking assumes the default frequency and indicates no signal the frequency measurement is set to zero Hertz Service M anual R5942B Chapter 6 Page 42 of 91 Remote Access
75. decay now the thermal replica is used Kreset was the time constant of the exponential now itis the thermal capacity constant for cooling July 1995 Dave Banha m Publicity Styles changed Description of frequency tracking inputs improved Bullet added to operational events list to indicate for software version 18LG PG 002 XXXEB onwards that the state of the scheme output menu cell in auxiliary functions is now logged at reset and whenever it is changed Description of event logging when real time clock set changed to reflect software version 18LG PG 002 XXXEB Previous versions of the software only logged the real time clock invalid event Feb 1996 Dave Banham Publicity Section 3 5 3 corrected formulae for the vector transformation ANSI device numbers corrected in Figures 21 and 22 Service M anual LG PG111 fa 1 2 1 3 1 4 alia 1 6 co N OA a A W alele tees hes Ww WwW WwW WS W N N N N N N N N N N N N N NY N FO 3 2 1 3 2 2 3 3 33l 3 3 2 3 4 Bul 3 4 2 33 3 3 5 1 3 5 2 3 5 3 Contents IN TRO DUCTIO N IN PUT SIG N ALPRO CESSIN G Analogue inputs Generator differential CT inputs Earth CT inputs N eutral VT input Phase CT inputs Sensitive A phase CT input Phase VT inputs Anti aliasing filters Data sampling Fourier filtering M agnitude approximation Phase angle calculation Frequency tracking Error compensation P
76. due to transient over voltages that do not pose a risk to the generating plant e g following load rejection with non hydro sets The typical delay to be applied would be 1s 3s with a longer delay being applied for a low voltage threshold setting W hen selecting instantaneous operation of the LGPG111 high set over voltage protection function the typical threshold setting to be applied would be 130 150 of the nominal phase phase voltage seen by LGPG111 depending on plant manufacturers advice Under frequency protection function 81U Summary Two under frequency stages each with an independent timer e First stage can be used to initiate load shedding for industrial systems Time delayed to allow any down stream load shedding equipment to operate first Second under frequency stage to trip more rapidly A dedicated input is provided to block the operation of the under voltage and under frequency protection during run up or run down of the generator This input can be driven from an auxiliary contact in the circuit breaker The under frequency protection function of LGPG111 utilises the AC voltage input signals as the frequency measurand Two independent time delayed stages of under frequency protection are offered by LGPG111 Each stage is provided with an under frequency threshold setting F1 lt F2 lt and with a time delay setting t1 t2 As well as being able to initiate generator tripping the under frequency prot
77. failure protection function is otherwise uncertain a stand alone protection scheme using HV current and voltage signals should supplement LG PG 111 The delayed detection and tripping offered by the LG PG 111 field failure protection function should however be adequate for many applications Service M anual R5942B Chapter 3 LGPG111 Page 69 of 75 Base MVA 152 35 MVA Xd 195 Xd 18 1 Xt 17 7 Xs 1 83 17 4kA at 275kV Eg Es 0 8 Case 152 35 MVA GT i pape pages Condition Xg Xd A g Es lt min Figure 30 Field failure protection function characteristics large generator R5942B Chapter 3 Page 70 of 75 Service M anual LG PG111 STANDARD FACTORY SETTINGS 4 An overview of the LGPG111 factory scheme logic settings is given in Figure 31 Diagram 08 LGPG111 01 in chapter 11 details all the standard factory settings for the protection and scheme logic N ote that the frequency tracking default is set to 50Hz in the System Data Section This should be set to 60Hz for 60Hz countries although no harm will result if itis not 9 LA 494d La fololole fololelo folololo folololo folofo fololejo lolo olo ololojo 110 A dwog ZA olojlojo ololojo olojo o ololojo o ojo ojojojo o jojojo o jojojo WIV SdN olololo fofolol
78. fault protection A suitable 100 stator earth fault protection scheme can be applied to supplement the LG PG 111 in these cases However the relaying technique Service M anual R5942B LG PG111 Chapter 3 Page 23 of 75 must be carefully selected so that it will be able to function correctly for the particular application especially in the case of variable frequency operation For most generator protection applications the added complexity of providing a universally effective form of 100 stator earth fault protection is questionable W here stator winding inter turn fault protection is required see discussion in Section 2 2 the current operated stator earth fault protection function might alternatively be used to provide this form of protection using an additional single CT as illustrated in Figure 11 In this case the neutral voltage displacement protection 59N would act as the main form of stator earth fault protection even though the current operated protection function as applied in Figure 11 could still respond to some stator earth fault conditions This form of interturn fault protection using the main current operated element le gt offers the possibility of greater sensitivity compared to the technique discussed in Section 2 2 using the differential protection function This is due to the fact that the required ratio of the single CT for this application is arbitrary The current setting of the main current operated eleme
79. for two under and one over frequency protection functions 12 1 Under frequency 1 status The protection function can either be enabled or disabled The setting is password protected 12 2 amp 12 3 Under frequency 1 settings 12 4 Under frequency 2 status The protection function can either be enabled or disabled The setting is password protected 12 5 amp 12 6 Under frequency 2 settings 12 7 Over frequency status The protection function can either be enabled or disabled The setting is password protected 12 8 amp 12 9 O ver frequency settings Service M anual R5942B LG PG111 Chapter 6 Page 58 of 91 7 14 Voltage protection Item Front Panel Remote Access 13 0 VOLTAGE Voltage Protection PROTECTION 13 1 27 Under Voltage 27 Under Voltage Enabled Enabled 13 2 27 Under Voltage V lt 60 V NS 60 V 13 3 27 Under Voltage te 1 0 s Ee 1 0 s 13 4 59 Over Voltage 59 Over Voltage Enabled Enabled 13 5 59 Over Voltage v gt 140 V V gt 140 V 13 6 59 Over Voltage t gt 5 0 s t gt 5 0 s 13 7 59 Over Voltage vV gt gt V V gt gt 160 V 13 8 59 Over Voltage t gt gt O28 t gt gt 0 2 s 13 9 60 Volt Balance 60 Voltage Balance Enabled Enabled 13 10 60 Volt Balance Vs gt 10 V Vs gt 10 V Table 33 The LG PG111 s Voltage protection Section of its menu Settings for under and over
80. function the Protection O peration Summary Section of the relay s menu can be used to determine the point at which this function starts to operate The Protection O peration Summary should indicate 0 when the current injected is increased to the pick up point the displayed percentage will start to increase this is the pick up point the displayed value will rise from 0 and displays 100 when the time delay has expired Accept and reset all alarms on the relay pick up value le gt setting with a 5 tolerance drop off value 95 of le gt setting with a 5 tolerance Measurement of time delay characteristic Service M anual R5942C LG PG111 Chapter 8 7 6 3 7 6 4 Page 33 of 66 Inject 2 x le gt Amps into the input terminals A5 A6 to obtain the operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check the ALARM Protection 51N gt SEF appears on the display ignore other alarms Reset all alarms on relay For the DT characteristic O perating time t seconds with a 5 tolerance 10 to 40mS where tis the applied setting For the SI characteristic O perating time 10 03 x TMS seconds with a 5 tolerance 10 to 40mS where TMS is the applied setting O peration of output relays for 51N gt Repeat the previous injection test to operate the 51N gt Check the operation of the LG PG111 s output relays against the scheme logic settings Re
81. functions A Print function is provided in the Auxiliary Functions menu Section to allow information to be printed out through the parallel port to a printer Information available for printing are 1 System settings 2 Protection settings 3 Scheme logic settings 4 Event and fault records Each printout also contains the Plant Reference identification and a time and date stamp Self monitoring The LGPG111 includes a number of self monitoring features designed to guard against hardware or other fatal errors from causing maloperation of the relay Self monitoring checks are performed during power up runtime and background processing Power on diagnostics During power up the relay runs its diagnostic program to check the main relay components watchdog timer microprocessor interrupt controller DMA controller timers LCD and memory components Random access memory RAM is checked by read write tests to each location Erasable programmable read only memory EPRO M is verified by checksum tests In addition the integrity of data stored in both EEPRO M s of the main processor and analogue input modules are validated by CRC checksum tests Any major error detected by the power on diagnostics will cause the relay to lock out The exceptions are failures of the watch dog and the LCD display which will only cause an alarm to be raised Run time and background self monitoring During run time the relay monitors the
82. generator terminals will be highly reactive and will be less than the direct axis synchronous reactance of the machine X A typical minimum value for this impedance is twice the direct axis transient reactance of the generator 2X for a level of slip below 1 Figure 17 shows a typical machine terminal loss offield impedance locus which illustrates the effect of rotor flux decay leading to gentle pole slipping and eventual stabilisation as an induction generator with a level of slip of around 1 To quickly detect a loss of field condition where machine damage may occur the diameter of the LG PG 111 field failure impedance characteristic Xb should be set as large as possible without conflicting with the impedance that might be seen under normal stable conditions or during stable power swing conditions To meet this objective itis recommended that the diameter of the LGPG111 impedance characteristic Xb is set equal to the generator direct axis synchronous reactance in secondary ohms The characteristic offset Xa should be set equal to half the direct axis transient reactance O 5X in secondary ohms Thus Xb X x CT ratio VT ratio Xa 0 5X x CT ratio VT ratio W here Service M anual R5942B LG PG111 Chapter 3 Page 50 of 75 Xb Required impedance characteristic diameter in secondary ohms Xa Required impedance characteristic offset in secondary ohms X Generator directaxis synchronous reactance in primary ohm
83. headings section text amp section values commands Service M anual LG PG 111 7 7 1 MENU SYSTEM Menu contents Item 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 11 0 12 0 13 0 14 0 15 0 16 0 17 0 18 0 19 0 20 0 21 0 LABELS Front Panel SYSTEM DATA AUXILIARY FUNCTIONS TRANS FORMER RATIOS MEASUREMENTS 1 MEASUREMENTS 2 VIEW RECORDS INPUT OUTPUT REMOTE COMMUNICATIONS DISTURBANC Pd RECORDER TEST FUNCTIONS PROTECTION OP SUMMARY R5942B Chapter 6 Page 22 of 91 Remote Access System Data Auxiliary Functions Transformer Ratios Measurements 1 Measurements 2 View Records Protection Function Status Generator Differential Earth Fault Protection Voltage Dependent Overcurrent Power Protection Frequency Protection aaoo Voltage Protection Negative Phase Sequenc Field Failure Scheme Logic Input Output Labels Remote Communications Disturbance Recorder Test Functions Protection Operation Summary Table 3 The LGPG111 s menu contents list alternative setting group disabled Service M anual LG PG111 R594
84. healthy LED is not illuminated see chapter 7 Testing the power supply failure alarm De energize the relay and check that the contact across relay terminals H3 H4 opens and the contact across H5 H6 closes Check the remote power supply failure alarm if connected is on Re energize the relay Set the correct date and time on the relay as follows W ith the default display indicating DATE AND TIME NOT SETUP press gt 1 gt keys The relay should now be displaying the date and time in the Auxiliary Functions Section of the menu Press key the year should flash press the T or J keys to set the correct year Press the J keys to move the cursor to the month and then set the correct month by following a similar procedure for setting the year Set the date and time After the time is set press the SET key to confirm the setting Testing the LED s Press the arrow keys to display Lamp Test in the Test Functions Section Press the key to display Press SET for Lamp Test Press the SET key Check the red LED and the two yellow LED s on relay front panel light up momentarily and the green LED extinguishes momentarily SECONDARY INJECTION TESTS PRELIMINARIES Choice of commissioning tests Traditionally generator protection has been provided by using several discrete relays to achieve overall protection the LG PG111 integrates these functions within one unit W ith discrete relays it was necessa
85. i analogue module ii main processor module e Setting group select logic input failure Fault recording The fault recording is designed to capture power system data when the relay trips Since the LGPG111 has no pre defined output contact for tripping a Fault Record Trigger setting is available to select one or more of the fifteen output relays as the fault record trigger W hen the fault record trigger occurs an alarm is raised causing the yellow alarm LED to flash and the red trip LED to illuminate The alarm messages will indicate which output relays have energised together with the operation of the protection functions and possibly the status inputs The fault record consists of the following information 1 Date and time of the recording 2 Protection function operation including the faulted phase information if applicable 3 Status of the relay outputs 4 Status of the logic inputs excluding the real time clock synchronisation input and the group selection inputs 5 The Scheme O utput setting to indicate whether the outputs were blocked when the trigger occurred 6 The active setting group number 7 A snapshot of the measurement values taken when the trigger occurred A fault record is essentially a special event record with additional measurement values O ut of the 100 event records up to 50 fault records can be accommodated The records are stored in non volatile EEPROM memory and are preserved even in c
86. in a single integrated package see Figure 1 Flexible scheme logic is also provided to allow the protection output contacts of the package to be configured to execute required categories of action O pticallyisolated logic inputs are provided to allow the status of external plant to be monitored and to exercise control over the protection functions It is also possible for mechanical protection functions to initiate alarms or action via the LGPG111 scheme logic and to be monitored via the serial communications facility provided with the protection package Service M anual R5942B LG PG111 Chapter 3 Page 8 of 75 Under voltage Low forward power Reverse power Field failure Negative phase sequence Stator earth fault Voltage dependent overcurrent Over voltage Neutral voltage displacement Voltage balance Sensitive directional E F Over frequency Under frequency Generator differential Figure 1 Protection functions provided by the LGPG111 relay W ith its frequency tracking system the LG PG 111 is able to maintain all protection functions in service over a wide range of operating frequency It should not be necessary for instance to disable the negative phase sequence thermal protection when running a generator at low frequency as might be necessary with existing discrete relay schemes This LGPG111 capability will be of especial interest for pumped storage generation schemes where synch
87. input and inject zero Amps into the input Slowly increase the current to measure its pick up and drop off values pick up value lep gt setting with a 5 tolerance drop off value 0 95xlep gt setting with a 5 tolerance Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check ALARM Protection 67N SDEF appears on the display ignore other alarms Reset all alarms Measurement of RCA Inject 0 2A into and rated current into legua Rotate the phase difference lagging to measure the phase angle when the relay picks up and drops off Also measure the relay operating angle region Rotate the phase difference leading to measure the pick up and drop off phase angles and the relay operating angle region again Record the phase angles measured Pick up phase angles RCA 90 with a 5 tolerance Drop off phase angles RCA 95 with a 5 tolerance O perating region RCA 90 to RCA 90 with a 5 tolerance O peration of output relays Repeat the previous injection test as appropriate to operate the 67N SDEF Check the operation of the LG PG111 s output relays against the scheme logic settings Record the output relays operated 51N Stator earth fault This protection function is current operated and can be set to cover up to 95 of the Service M anual R5942C LG PG 111 7 6 1 7 6 2 Chapter 8 Page 32 of 66 stator windings Itis normally applied
88. is fatal or disable the protection by placing the relay out of service 3 The relay will not function correctly The following hardware fault finding instructions are therefore divided into two main sections 1 Power on failures 2 General operational failures Service M anual R5942C LG PG 111 Chapter 7 Page 6 of 14 Important 1 Before beginning any fault finding procedures visually check all connections and link positions on all modules Chapter 5 provides this information 2 Ensure each module is in its correct position in the relay case the module identification numbers should correspond with the mod ule numbers on the relay case and with the module identification list fixed to the reverse side of the front panel 3 When replacing modules ensure the replacement has the same module number as that which it replaces 4 Ensure no modules show signs of obvious damage due to im proper handling 5 Check the ribbon cable bus is connected correctly to each module and that no socket pins are bent or otherwise damaged 1 3 Initialisation sequence The following sequence of events should occur when the DC auxiliary supply is ap plied to the relay s DC supply terminals 1 The relay s display shows COLD RESET on the top line with the current power on diagnostic test being performed on the bottom line 2 The power on diagnostic tests proceed through several tests 3 The display changes to the
89. is increased to the pick up point the displayed percentage will start to increase this is the pick up point the displayed value will rise from 0 and displays 100 when the time delay has expired pick up value I gt setting with a tolerance of 5 l drop off value I gt setting x 0 95 with a tolerance of 5 Measurement of time delay characteristics W ith the conditions and connections as above set the time delay characteristic to DT definite time with the setting t setto 2 0 seconds and the TMS set to 1 0 Inject 2 0 x rated current into the I input terminals A11 A12 measure and record the operating time O perating time 2 0 seconds with a 5 tolerance 10 to 40mS Service M anual R5942C LG PG 111 6 1 4 6 1 5 6 2 Chapter 8 Page 18 of 66 Change the settings so that the time delay characteristic is set to SI standard inverse Inject 2 0 x rated current into the input terminals A11 A12 measure and record the operating time O perating time 10 03 seconds with a 5 tolerance 10 to 40mS Repeat the test but this time inject 10 0 x rated current into the input terminals A11 A12 measure and record the operating time O perating time 2 97 seconds with a 5 tolerance 10 to 40mS Fault record checks Use the front panel keys to navigate to the menu section View Records and ensure that the records match the injected faults carried out above Thermal curve cha
90. island power system with generators connected to medium voltage feeders it may be that generator under voltage protection would be the only form of protection that could reliably detect a feeder remote end three phase fault where the feeder protection or feeder circuit breaker fails In the case of large thermal power plant generators a prolonged under voltage condition could adversely affect the performance of the auxiliary plant such as boiler feed pumps and air blowers This would ultimately have an effect on the primary plant performance If such a situation is envisaged the application of time delayed under voltage protection to trip the generator might be a consideration If the LG PG 111 under voltage protection function is to be enabled the under voltage threshold V lt should be set below the steady state phase phase voltage seen by the LG PG111 for a three phase fault at the remote end of any feeder connected to the generator bus or up to selected locations within an industrial power network Allowances should be made for the fault current contribution of parallel generators which will tend to keep the generator voltage up Equations for determining the phase phase voltage seen by the LG PG 11 under such circumstances are given in Section 2 6 Service M anual R5942B LG PG111 Chapter 3 2 11 Page 53 of 75 The time setting of the under voltage protection function t should be set longer than the time required for backup fe
91. labels are used during the configuration of the scheme logic by the input and output status Service M anual R5942B LG PG111 Chapter 4 4 2 4 2 1 4 2 2 Page 37 of 50 displays and by the event fault and disturbance recording systems Scheme logic examples The flexibility of the LG PG 111 s scheme logic can be illustrated by way of the follow ing examples Blocking with the voltage balance function In this example the differential protection is required to trip the circuit breaker di rectly The voltage dependent overcurrent function is also used to trip the circuit breaker butis to be blocked by the voltage balance function if there is a protection VT fuse failure Additionally an alarm indication is to be given when the voltage balance function operates Figure 29 illustrates the scheme logic arrangement Relay 15 is assigned to trip the circuit breaker and Relay 8 is assigned to give VT fuse failure alarm indication The differential function is connected directly to operate Relay 15 In this case the AN D gate simply serves as a through connection The voltage dependent overcurrent function is also connected to operate Relay 15 butis gated with the inverted output from the voltage balance function The AN D gate therefore blocks the voltage de pendent overcurrent whenever the voltage balance protection operates The non inverting output from the voltage balance function is connected separately to operate Relay 8 f
92. lead from relay to current transformer Q R Resistance of any other protective relays sharing the current transformer Q r W ith a boundary condition of through fault current lt 10In and X R ratio lt 60 the kneepoint voltage requirement is V 2301 R 2R R with a minimum of 34V Service M anual R5942B LG PG 111 5 1 2 5 2 5 3 3l Chapter 3 Page 72 of 75 For class X current transformers the excitation current at the calculated kneepoint voltage requirement should be less than 2 51 For IEC standard protection class current transformers it should be ensured that class 5P are used High impedance differential protection If the generator differential protection function is to be used to implement high impedance differential protection then the current transformer requirements will change For this reason please contact the Engineering Department of ALSTOM T amp D Protection amp Control Limited for advice on selecting suitable current transformers Voltage dependent overcurrent field failure and negative phase se quence protection functions When determining the current transformer requirements for an input that supplies several protection functions it must be ensured that the most onerous condition is met This has been taken into accountin the formula given below The formula is equally applicable for current transformers mounted at either the neutral tail end or terminal end of the generator V
93. limi tthe minimum operating time of the negative phase sequence thermal protection function to allow sufficient time for downstream protection and fault clearing devices to clear heavy unbalanced faults on the power system fed by the protected machine The LGPG111 negative phase sequence thermal protection function can be set to have a definite minimum operating time tM IN This time delay should be set to co ordinate with close up clearance of feeder phase to phase or phase to earth faults by feeder backup protection under minimum plant conditions For either fault condition the negative phase sequence current seen by the LGPG111 and the thermal protection function operating time should be determined The definite minimum time setting tM IN should be set to provide an adequate margin between the operation of the negative phase sequence thermal protection function and external fault clearance protection The co ordination time margin used should be in accordance with the usual practice adopted by the customer for backup protection co ordination For levels of negative phase sequence current that are only slightly in excess of the setting I2 gt gt there will be a noticeable deviation between the LG PG 111 true thermal protection currenttime characteristic and that of the simple t characteristic offered by many traditional static relays For this reason a maximum negative phase sequence protection function trip time setting is offered by
94. ms 27 26 n o 2 ms 8 ms 28 Table 7 Terminal allocation of the relay output module Microcomputer amp serial communications Module number GM0099 M icrocomputer board The module consists of a powerful 16 bit microprocessor Intel 80C 186 XL featuring integrated on chip peripherals These peripherals include a timer unit with three programmable timers a direct memory access DMA unit a programmable interrupt controller unit ICU and an address decoder unit Eight 28 pin JEDEC memory sockets are provided For the LGPG111 the memory sockets are populated with 64 kilobytes of RAM 16 kilobytes EEPROM and 128 kilobytes of EPROM giving a total of 208 kilobytes of memory The module In the table n o means normally open contact and n c means normally closed contact with respect to the common terminal or terminal pair Service M anual R5942B LG PG111 Chapter 5 5 3 2 5 4 5 4 1 5 4 1 1 5 4 1 2 Page 11 of 23 incorporates a watchdog timer to ensure an orderly restart in the unlikely event of a system crash An RS232 compatible serial interface controlled by a universal synchronous and asynchronous receiver transmitter USART allows serial communication with the microprocessor for factory test purposes The microcomputer module controls the I O bus All modules connected to the bus work as slave I O modules to the microcomputer module The module is powered from the 6 5V and 19 5V bus rails Ser
95. multi stage system load shedding Frequency fn System frequency response with minimum load shed for recovery System frequency response with under shedding of load Optimum underfrequency F protection characteristic t2 tl Time Figure 18 Co ordination of under frequency protection function with system load shedding Service M anual R5942B LG PG111 Chapter 3 Page 56 of 75 quency Under fre 81U 1 RL13 Trip local loads Under frequenc Energised via the 81U 2 E breaker 52b contact RL15 Voltage balance P 60V RL8 Fuse failure alarm RL15 RLI3 RL8 Figure 19 Initiating local system load shedding using the under frequency protection 2 13 For industrial generation schemes where generation and loads may be under common control ownership one of the LG PG111 stages of the under frequency protection function could be used to directly initiate local system load shedding This could be arranged by suitably setting up the LG PG 111 flexible scheme logic matrix as illustrated in Figure 19 To prevent under frequency protection tripping following normal shutdown of a generator a normally closed circuit breaker auxiliary contact should be used to energise the under frequency protection function inhibit logic input 0 W hen this input is energised under frequency protection function trip initiation and alarm initiation will be blocked Over frequency protection function 810 Summary Single over
96. only the 27 will cause the output relays to operate There is no need to change the input matrix for blocking by the Voltage Balance element Measurements Inject rated voltage from into the V input terminals B25 B26 Record and check the voltage injected and the voltage measured by the relay Repeat for the V input terminals B27 B28 Allowing 3 tolerance Characteristic and operating time Record the under voltage settings V lt and t The under voltage protection is a 3 phase function which operates when V V are below the setting V and ab M easurement of V lt Inject V lt Volts into the V input terminals B25 B26 to check the pick up and drop off values note V 0 andV V Pick up voltage V lt setting with a 5 tolerance Drop off value is 1 05xV lt with a 5 tolerance Repeat the injection into the V input terminals B27 B28 to check the pick up and drop off values Reset all alarms Service M anual R5942C LG PG 111 7 12 3 7 13 7 13 1 7 13 2 Chapter 8 Page 54 of 66 M easurement of time delay characteristic t Inject rated current into the I input terminals A11 A12 as this will stop the under voltage protection being inhibited when the volts are removed Inject rated voltage into the V input terminals B25 B26 Reset all alarms Stop the voltage injection at the same time as starting a timer to obtain the operating time Check the red Trip LED turns on and the
97. operate The Protection O peration Summary should indicate 0 Service M anual R5942C LG PG111 Chapter 8 1 1 3 1 1 4 7 1 5 Page 35 of 66 when the voltage injected is increased to the pick up point the displayed percentage will start to increase this is the pick up point the displayed value will rise from 0 and displays 100 when the time delay has expired V pick up value Ve gt setting with a 5 tolerance V drop off value 95 of Ve gt setting with a 5 tolerance Measurement of time delay characteristic Ensure the output contact connected to the timer on the test set is operated by the 59N 1 and not by the 59N 2 Inject 2 x Ve gt Volts to obtain the operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check ALARM Protection 59N 1 ND appears on the display ignore other alarms Reset all alarms O perating time the setting tl with a 5 tolerance 10 to 40mS O peration of output relays for 59N 1 Inject 2xVe gt Volts into the V input terminals B19 B20 to operate the 59N 1 Check the operation of the output relays against the scheme logic settings Record the output relays operated O perating time for 59N 2 If the 59N 2 is not used in the scheme logic there is no requirement for the following 59N 2 tests If necessary change the scheme logic input matrix so that only the 59N 2 will cause the output relays to operate Reco
98. port or to a protocol converter such as the KITZ101 which converts to IEC 870 K Bus is ideal for applications with a number of relays fitted with K Bus ports since they can all be daisy chain connected into a single cable length Typical applications for this might be for sites with more than one LG PG 111 installed but it might also encompass other protective relay devices such as the ALSTOM T amp D Protection amp Control Limited K Series range for transformer and feeder protection M aximum cable lengths are largely determined by capacitive effects the figures quoted here are only typical and it may be possible to improve on them Service M anual R5942B LG PG 111 6 1 6 2 6 3 Chapter 6 Page 20 of 91 SECURITY Password protection Password protection is only provided for those settings which relate to the external configuration of the relay In this respect they are set up during commissioning and the password protects against any accidental change which may seriously affect the ability of the relay to perform its intended functions Settings under password protection are Protection function status settings Protection function characteristic selection Scheme logic settings The system CT and VT ratios Logic input and scheme output labels Scheme Inhibit remote setting capability and the alternative setting group selection commands The password is four upper case alpha characters long The default password
99. protection 59 Under Voltage protection 27 O ver Frequency protection 810 Under Frequency protection 81 U Voltage Balance protection 60 The single line diagrams in Figures 3 and 5 illustrate how the relay might be applied for various generator configurations and ratings Figures 4 and 6 show the respective relay connections 2 2 Generator differential protection function 87G Summary e Protects against failure of the stator winding insulation Compares the current on the neutral side of the generator with the current on the line side Requires the use of matched CT s Uses a low impedance dual slope bias characteristic to achieve high sensitivity for internal faults but stability for external faults W here an in zone unit transformer or in zone variable frequency starting unit exists additional CT s may be required Can be arranged to offer high impedance type protection using an exter nal stabilising resistor Can be arranged to provide interturn protection for certain stator winding arrangements Service M anual R5942B LG PG111 Chapter 3 Page 12 of 75 The generator differential protection function compares the signals from the LG PG 111 neutral end and terminal end three phase CT inputs to detect faults within the stator winding A dedicated set of neutral end CT inputs is provided to allow the option of using a dedicated set of main CT s for differential protection The input CT s
100. quick method of setting all the bits to zero and hence resetting all the outputs All the bits are reset when the scheme output is re enabled The bits are summarised in Table 8 page 29 Bit 0 the Relay Inoperative Alarm is normally operated to indicate that the LG PG 111 is functioning correctly Setting bit 0 to a 1 will invert this output s State and cause it to reset The Relay O utput Status cells in the System Data and Auxiliary Functions Sections will not reflect the bit pattern in this cell Instead these cells reflect the output from the scheme logic Scheme logic test A subtitle cell for the remote system only All the scheme logic tests are indented below Group 1 scheme logic test A subtitle cell for the remote system only W hen the alternative setting group has been enabled this cell is visible and the group 1 scheme tests are indented below Scheme setting check G roup 1 Provides an indication of any incompletely programmed scheme logic lines The check is limited to finding logic lines which have bits set in only the input AND matrix or the output O R matrix and not both It cannot detect logic errors resulting from programming the bits The check starts at logic line zero and progresses towards logic line 31 The first partially programmed logic line is indicated by Error in Line Xx where xx is the logic line number If no errors are detected then ox is indicated W hen alternative
101. rated volts into the V input terminals B25 B26 Slowly reduce the current to check the 32R Reverse Power pick up and drop off values Record the current injected Pick up Power Measured pick up current x Rated voltage V3 Check that the measured value is within 5 of the set value P The Drop off value should be within 95 of the pick up value W ith the connections and conditions as above inject a current of twice the pick up value then reduce the current to zero at the same time as starting the timer in order to obtain the operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay trips Check ALARM Protection 32R RP appears on the display Ignore other alarms Reset all alarms Record the operating time O peration time the setting t allowing 5 tolerance 0 to 120mS Service M anual R5942C LG PG111 Chapter 8 7 3 3 7 4 7 4 1 Page 27 of 66 O peration of output relays Repeat the previous injection to operate the 32L Check the operation of the LG PG111 s output relays against the scheme logic settings Record the output relays operated Restore the original Scheme Logic settings if changed Field failure Severe loss of excitation caused by field failure can cause a high value of reactive current to be drawn from the power system which can endanger the generator The field failure protection provided by the relay is a single phase measuring element with
102. self checking which allows the microprocessor to test the analogue circuitry up to and including the multiplexers As mentioned earlier all the current inputs are provided with gain switching to improve their resolution over a wide dynamic range A simple technique is used to manage the gain switching Each current input is sampled twice at x1 and x8 gain and stored in separate buffers A peak detector is used to check the data with the x8 gain If any of the last 12 samples exceeds 95 of the ADC saturation level the data from the x1 gain is selected This approach avoids the complexity of dynamically changing the gains during signal processing and ensures consistent amplification for the one cycle data window used by the Fourier filter algorithm Fourier filtering The input signals are processed using a 1 cycle Fourier filter The purpose of the filter is to extract the fundamental frequency component of a signal in vector form The Fourier filter algorithm can be expressed as 2 N 1 Is sanoi sin onAt x In N X Service M anual R5942B LG PG 111 Chapter 4 Page 12 of 50 NI 2 where N Number of samples per cycle System angular frequency in Instantaneous value of signal i sampled at time nAt Is Fourier sine integral of signal i Ic Fourier cosine integral of signal i ig Instantaneous value of signal i sampled at time 0 in Instantaneous value of signal i sampled at time N At If a signal at time tis expres
103. setting determines which of the stator earth fault timers is inhibited when the 51N Inhibit logic input is energised Either the high set or the low set can be selected Alternatively both timers can be inhibited or the function disabled entirely This setting is password protected Clock synchronised Specifies the period or time frame of the clock synchronism pulses to the Clock Sync logic input Time frames of 30 seconds 1 5 10 15 30 and 60 minutes can be selected Alternatively the function can be disabled For a given time frame setting a pulse on the Clock Sync logic input will cause the LGPG111 s clock to be adjust to the nearest whole multiple of the time frame Default display Specifies the front panel default display The cell can have a value of any of Title Description Model N umber Plant Reference Phase Currents Line Voltages Earth Q uantities N PS 12 Current Power Aph Phase Angle Aph System Frequency Date amp Time Active Group or All Measurements The content of each of the default displays is discussed in Section 4 2 page 9 Service M anual R5942B LG PG 111 Chapter 6 Page 36 of 91 7 4 Transformer Ratios Item Front Panel Remote Access 3 0 TRANSFORMER Transformer Ratios RATIOS 3 1 Display Value Display Value Secondary Secondary 3 2 Current R
104. setting transfer does not include any of these settings 18 1 Relay address The address of the LGPG 111 on a remote communications network Settable between 0 amp 255 A value of 255 effectively removes the relay from direct addressing over the network and a value of 0 is used as a transition address by a remote system a transition address is automatically changed by the remote system to a spare address on the network This cell is duplicated in the System Data Section 18 2 Remote setting Allows remote access setting capability to be Enabled or Disabled W hen disabled settings can only be changed through the front panel This setting is password protected and is duplicated in the Auxiliary Functions Section 18 3 Communications mode Selects which port the communications system will use Front Panel Remote Access Comms Mode Communications Mode Disabled Disabled Comms Mode Communications Mode K Bus K Bus Comms Mode Communications Mode Front IEC870 FT1 2 FrontIEC870FT1 2 Comms Mode Communications Mode Rear IEC870 FT1 2 Rear IEC870FT1 2 Table 41 States of the communications mode cell Service M anual R5942B LG PG111 Chapter 6 Page 66 of 91 If the communications hardware fails the disabled mode is automatically entered 18 4 Minimum transmit delay Determines the minimum response time of the LGPG111 in the range
105. so that fault records produced during commissioning can be identified with a scheme output inhibited The active group cell indicates which setting group was in use when the fault trigger occurred Cells 6 17 to 6 34 form a record of the power system measurements when the fault record trigger occurred Service M anual LG PG111 6 35 R5942B Chapter 6 Page 47 of 91 Fault Record Erased This cell is normally hidden and becomes visible when the selected fault record has no fault data fault data cells 6 12 to 6 34 are then hidden Itis possible to have fault records with no fault data because only 50 of the 100 event records can have fault record data W hen 50 fault records exist a new fault record will take the data store from the oldest fault record leaving just the time stamp information in the event record memory Service M anual R5942B LG PG 111 Chapter 6 Page 48 of 91 7 8 Protection function status Item Front Panel Remote Access ome f 7 0 PROTECTION FN Protection Function Status STATUS ie 7 1 87G Gen Diff 87G Generator Differential Enabled Enabled oa 7 2 51N Stator EF 51N Stator Earth Fault Enabled Enabled Wo ag 7 3 59N Neutral Disp 59N Neutral Displacement Disabled Disabled 7 4 67N SDEF 67N Sensitive Directional E
106. starta stop watch and waitfora 0 12 xKreset duration of 2 gt gt seconds which is the time taken for the thermal value to fall from 100 to 88 7 W hen the thermal value has fallen to 88 7 immediately re apply the injection fora second time and measure the relay s operating time K operating time 7 133 65 x 2 gt gt seconds with a 20 tolerance W here Kreset and 12 gt gt are the relay settings For software versions before 18LG PG002XXXEA the Kreset setting is used differently The test may be performed by following the stated injection procedure but wait for a duration of Kreset seconds before applying the second injection Service M anual R5942C LG PG111 Chapter 8 7 9 6 7 10 7 10 1 7 10 2 Page 49 of 66 _ 0 0645xK ae KG second operating time 2 gt gt seconds witha 20 tolerance n O peration of output relays for 46 gt gt N PS thermal trip Inject 3 5xl2 gt gt Amps into phase A N relay terminals A11 A12 to operate the 46 gt gt Thermal Trip Check the operation of the output relays against the scheme logic settings Record the output relays operated Restore the original Scheme Logic settings if changed 81U Under frequency There are two underfrequency elements which are used to detect overloading of the generator caused by various system disturbances or operating conditions M easurements Inject rated voltage with rated frequency into the V _ input termina
107. thatitis possible to access the differential current paths of the differential current protection function externally The addition of an external stabilising resistor would be necessary to create a highimpedance differential protection scheme For general application itis recommended that the most sensitive differential current setting Isl of 0 05In is applied This setting can be raised up to 0 1In in 0 01 In steps for applications where a relatively small unit transformer or excitation supply transformer is teed off within the zone of differential protection In such cases the differential setting should be based on preventing operation for faults on the LV side of the transformer or to try and grade the LGPG111 operating time with transformer fuse protection Differential Current Percentage Bias K2 Percentage Bias K1 NO TRIP Mean Bias Current Figure 8 Differential protection function operating characteristic Service M anual LG PG111 R5942B Chapter 3 Page 19 of 75 2 3 Stator earth fault protection function 51 N Summary Current operated from a CT in the neutral earth path Two independent tripping stages First stage tripping can incorporate either a definite time or standard inverse type IDMT delay Second stage tripping can be instantaneous or definite time delayed Can be used to provide interturn fault protection Immune to third harmonics Applied to directly connected generators The prot
108. the LGPG111 tMAX This maximum time setting also limits the tripping time of the negative phase sequence protection function for levels of unbalance where there may be uncertainty about the machine s thermal withstand W hen the protected generator sees a reduction in negative phase sequence current metallic rotor components will decrease in temperature Some rotor components as a result of their varied location in relation to other components materials and degrees of forced cooling could have differing cooling time constants Additionally these same components could well have differing shorttime thermal capacities I t values In the case of cyclic application of negative phase sequence current such as multiple faults occurring on a power system during severe weather it is theoretically possible for a component with a larger shorttime thermal capacity to overheat even though a component with a smaller shorttime thermal capacity does not For applications where such effects need to be considered the LGPG111 is provided with a separate thermal capacity setting Kreset for use when the machine is cooling due to a reduction in l For general applications the Kreset setting should be set equal to the main time constant setting K Service M anual R5942B LG PG111 Chapter 3 2 9 Page 47 of 75 A definite time alarm stage has been traditionally provided with negative phase sequence protection relays since prolonged small levels of ne
109. the VT A 5 to 5 compensation is possible in 0 1 steps The setting shifts the voltage vector according to the following formula Sp Vab Va V3 An integrating timing arrangement is available with both power functions the logic of which is discussed in Section 3 13 page 34 x 1Z 30 8comp Settings and characteristic The settings provided by both functions are as follows Compensation angle 8comp Compensation angle setting applied to both reverse power and low forward power functions Reverse power 32R P gt Reverse power threshold t Timer setting tDO Delayed drop off timer for integrated timing Low forward power 32L P lt Low forward power threshold t Timer setting tDO Delayed drop off timer for integrated timing The criterion for operation of the reverse power is Va x Ta sensitive x cos 1 80 gt P gt The criterion for operation of the low forward power is Va x Ta sensitive x cos lt P lt The characteristics of both functions are shown in Figure 16 If la sensitive s greater than 1 05xIn then both functions will be blocked from opera tion This is to prevent any internal saturation effects from affecting the stability of the functions due to their sensitive angular accuracy requirements This overcurrent blocking feature together with the setting of the relay will determine the angular boundary of the reverse power function as shown in Figure 17
110. the conditions mentioned in Section 2 6 1 the steady state primary current and voltage magnitudes seen for a feeder remote end three phase fault are given as follows E n kS nR X X nX E V 3 nR 2 X nX 2 A mR X X 0X2 W here Minimum generator primary current seen for a multi phase feeder end fault Ve E No load phase neutral internal e m f of generator Xs Directaxis synchronous reactance of the generator Negative phase sequence reactance of the generator Step up transformer reactance Feeder positive phase sequence resistance x D XxX x lI Feeder positive phase sequence reactance n Number of parallel generators All above quantities are to referred to the generator side of the transformer The upper voltage threshold setting Vs1 should be set below the minimum corrected phase phase voltage level for a close up HV earth fault In the case of HV solid earthing this voltage would be a minimum of 57 of the nominal operating voltage The lower voltage threshold Vs2 should be set above the minimum corrected phase phase voltage level for the limiting remote end feeder fault condition considered above There would be no need for further reduction in current setting for closer faults Service M anual R5942B LG PG111 Chapter 3 2 7 2 7 1 Page 35 of 75 which would yield higher currents and lower voltages Further reduction in current setting for closer faults may m
111. the customer should decide whether to follow Section 6 or Section 7 Section 8 Logic input status checks Section 9 Contact checks Section 10 Scheme logic tests Error AutoText entry not defined is for recording the commissioning test results Two test forms are provided the appropriate form should be completed depending on which type of test is followed section 6 or section 7 Service M anual R5942C LG PG 111 2 Chapter 8 Page 8 of 66 TEST EQUIPMENT REQUIRED e 2 off variable current sources 1 off variable voltage sources e 1 off variable three phase supply which can be phase shifted 1 off variable frequency supply 1 off phase angle meter if applicable e 2 off multimeters 1 off timer 1 off stop watch if applicable Electronic test sets combine many of the above features into the one unit These type of test sets if available can reduce the time taken to commission the relay 3 3 1 3 2 COMMISSIONING PRELIMINARIES Warning Do not open the secondary circuit of a live CT since the high voltage produced may be lethal to personnel and could damage insulation Handling of electronic equipment Reference should be made to chapter 2 which describes a simple precautions to be taken before handling electronic circuits which may be sensitive to electrostatic discharge W ith in the front panel closed the relay is completely safe from electrostatic discharge Prior to commissioning the
112. the l and I inputs The voltage signals are from the V and V inputs V is derived from V and V by the following formula Va Va Vic Service M anual R5942B LG PG 111 3 5 2 Chapter 4 Page 22 of 50 The voltage dependent characteristic can be either voltage controlled or voltage restrained Voltage vector transformation is also provided for generators connected to the busbar by a delta star step up transformer as explained later W ithout voltage vector transformation the voltage quantity V used for the voltage dependent characteristic of the individual element is as follows For l element V Vab For lp element V Vbc For Ic element V Veca For applications which do not require a voltage dependent characteristic a simple overcurrent function can be selected The voltage controlled overcurrent function allows the timing characteristic to be changed from a load characteristic to a more sensitive fault characteristic when the voltage drops below a set level The voltage restrained overcurrent function allows the current pick up level to be proportionally lowered as the voltage falls below a set value This results in an infinite number of timing characteristics The timing characteristic can either be standard inverse or definite time An adjustable timer hold facility is available with this function as explained in Section 3 12 A logic input 51V Inhibit is provided which will reset all the o
113. the set level is evaluated by a simple calculation Applied where the generator is indirectly connected to the system via a step up transformer W hen negative phase sequence protection is also applied the voltage reduc tion due to a remote three phase fault need only be considered The voltage threshold should be selected to ensure that a voltage reduction due to a single phase to earth fault will not result in a change of the current setting The lower voltage threshold should be set slightly above the voltage level result ing from a remote three phase fault W hen set with a definite time characteristic this protection can be set equiva lent to underimpedance protection e A voltage transformation facility provides compensation for phase faults occurring on the HV side of a generator transformer The voltage dependent overcurrent protection function is a three phase protection function that is driven by the general protection CT inputs and which is intended to provide backup protection for an uncleared phase fault on the generator busbar or on a feeder from the busbar O peration of each overcurrent element can be made dependent on a phase phase voltage signal The A phase current element for example would be dependent on the A B voltage signal from the generator main VT circuits A facility has also been added to determine and use voltage signals that are equivalent to the HV phase phase voltage signals where a Yd1 or Yd11 s
114. to the reference VT inputs of the LGPG111 The other set should be connected to the main VT inputs and to any other items of voltage dependent generator protection see Figures 3 amp 4 With this arrangement the LGPG111 voltage balance protection function will be able to detect blown VT secondary fuses but not a blown VT primary fuse Differential 87G RL15 Trip CB dependant overcurrent 51V Voltage balance 60V 87G 51V 32L 27 40 60V 60V RL8 Figure 20 Fuse failure interlocking of voltage sensitive protection functions The voltage balance threshold setting should be set to minimum 5V unless two VT s of differing ratio are used or unless the standing unbalance due to differing VT loading causes false VT failure alarms during normal operation Service M anual R5942B LG PG111 Chapter 3 3 3 1 Page 59 of 75 OTHER PROTECTION CONSIDERATIONS Dead machine protection For a multiple source power system closure of a generator circuit breaker must be controlled either by automatic synchronising equipment or by manual breaker closing carried out with the aid of synchronising instruments and supervised by a synchronism check relay W hilst inadvertent closure of a generator circuit breaker should not be possible a small risk does exist especially when fault finding carrying out maintenance tests or testing control systems The possible damage caused by connecting a dead machine to a live power system or energ
115. utput Relays 51N Stator Earth Fault Measurement Checks Characteristic and O perating Time for 51N gt O peration Of Output Relays for 51N gt R5942B Chapter 9 Page 4 of 52 16 16 17 17 17 17 18 19 19 19 19 20 20 20 20 21 21 21 21 22 22 22 23 24 24 24 24 Service M anual LGPG111 Characteristic And Operating Time For 51N gt gt O peration Of Output Relays For 51N gt gt 59N Neutral Displacement M easurement Checks Characteristic And Operating Time for 59N 1 O peration Of Output Relays For 59N 1 O perating Time For 59N 2 O peration Of Output Relays For 59N 2 51V Voltage Dependent O vercurrent M easurement Checks Characteristic and O perating Time for Restraint Function if applicable Characteristic and Operating Time for Controlled Function if applicable Characteristic and Operating Time for Simple Function if applicable Fault Record Checks O peration Of O utput Relays 46 Negative Phase Sequence M easurements Characteristic And O perating Time For 46 gt N PS Alarm O peration Of O utput Relays For 46 gt N PS Alarm Characteristic And O perating Time For 46 gt gt N PS Thermal Trip 46 gt gt NPS Thermal Trip Reset Time O peration Of O utput Relays for 46 gt gt N PS Thermal Trip 81U 1 Under Frequency M easurements M easurement of Fl lt M easurement of O perating Time O peration Of O utput Relays R5942B Chapter 9 Page 5 of 52 24 25 26
116. voltage Vx 2 To reduce power dissipation caused by current flowing in the isolation circuitry a strobing technique is adopted which only allows current to flow into the circuitry when the status inputs are being read Calibration data storage To increase the accuracy of the analogue inputs software calibration is employed to correct the magnitude and phase errors which occur due to component tolerances on the input circuits In order to make the modules fully interchangeable it is necessary to store this information within the analogue input module To facilitate this 128 bytes of non volatile memory EEPRO M is available which is directly mapped on to the I O bus Connections Connections to external wiring are made via two 28 way M IDO S connectors which provide a CT shorting facility for the CT inputs Terminal allocation of the input module is given in Tables 13 amp 14 See the LGPG111 external connection diagram for details of input function assignment The module is powered from the 6 5V and 19 5V rails of the I O bus Front panel user interface Module number GM0025 The user interface is mounted in the hinged front panel It consists of a 2 row by 16 Service M anual R5942B LGPG111 Chapter 5 Page 17 of 23 Terminal Number Description 5 Start Earth Path Current 6 End le 7 Start Residual current 8 End l Residual 9 Start Reverse Power Ph A 10 End la s
117. which can be set to be more sensitive than the thermal function The alarm element can be used to provide a warning about unreasonable unbalanced load conditions The negative phase sequence component of the three phase currents is derived by the formula la a xlp axle h 2 3 where a is 1120 Settings and characteristic The settings provided by this function are as follows Thermal trip element 2 gt gt The lp threshold for the thermal trip element N ormally set to the maximum negative phase sequence withstand of the generator K Thermal capacity constant heating equivalent to the generator s shorttime I22t withstand ability Defines the rate of heating Kreset Thermal capacity constant cooling Identical to K but defines the rate of cooling for the thermal characteristic N ormally set equal to K TMAX Maximum operating time tMIN Minimum operating time Alarm element 12 gt l2 threshold for the alarm element t Definite time setting The LG PG111 negative phase sequence tripping function is a true thermal replica characteristic which takes into account heat dissipation and also the effects of stand ing low level negative phase sequence currents The thermal characteristic also caters for cooling due to a reduction in l2 with an independent cooling time constant The relay thermal replica model can be expressed as 2 _ t12 gt gt O new O oa L s 8 a J K 0 0 2 gt gt 0
118. which winding connections are brought out and insulated Although the probability of such a fault would be low itis possibly the most serious electrical fault that could occur inter turn R fault CT s for other protection functions Note Bias slope of differential protection must be low up to Tg to give inter turn fault sensitivity Figure 7 Generator differential and inter turn fault protection For generators with multi turn stator windings there is the possibility of a winding inter turn fault occurring Unless such a fault evolves in nature to become a stator earth fault it will not otherwise be detected with conventional protection arrangements Hydrogenerators usually involve multi turn stator windings with parallel windings For such applications the parallel windings could be grouped into two halves and the generator differential protection could be applied as illustrated in Figure 7 to provide generator differential protection and a degree of interturn fault protection The sensitivity of the protection for inter turn faults would be limited by the fact that the two CT ratios applied must be selected in accordance with generator rated current A more sensitive method of providing inter turn fault protection using an additional Service M anual R5942B LG PG 111 Chapter 3 Page 18 of 75 single CT is discussed in Section 2 3 2 The LGPG 111 differential protection function is stabilised against unwanted operation
119. with operation of feeder earth fault protection or parallel generator sensitive earth fault protection The second protection stage will offer primary stator earth fault protection for the protected machine and back up protection for the rest of the power system when the protected machine is connected to the generator bus In the case of inversetime feeder earth fault protection better back up protection could be afforded by using the inverse time current operated protection function le gt Alternatively where KCGG KCEG relays are used to protect feeders it may be possible to eliminate any co ordination problem by interlocking the feeder relays and the LGPG111 as described in Section 3 4 In the co ordination example of Figure 10 a lack of co ordination is apparent for feeder earth faults with currents less than It must be ascertained that is less than the fault current for the maximum anticipated level of fault resistance and that remote earth faults resulting in a current of less than will be cleared by remote protection in less than the time setting of the second stage of neutral voltage displacement protection 59N 2 Alternatively an instantaneous low set earth fault element 50N F ofa KCGG feeder relay could be used to block the 59N protection of the LGPG111 relays see Section 3 4 The first protection stage 59N 1 should not be enabled in the group 1 LGPG111 settings unless it is being used in conjunction with the sens
120. would be far too slow the LG PG111 can be used with two groups of protection function settings In the normal setting group Group 1 the protection functions would be set for normal operation In Group 2 different protection settings can be selected to deal with special operating modes e g running as a synchronous compensator or in pumping mode for pumped storage plant The second group of settings Group 2 could also be instated when a machine is not in service and the overcurrent and field failure protection functions could be set to initiate breaker tripping with a zero time delay if the machine is energised with the second group of settings instated The overcurrent protection function could also be set with a reduced current threshold setting I gt in the second setting group Automatic selection of the second group of protection function settings Group 2 could be arranged as illustrated in Figure 21 The under voltage protection function threshold setting V lt and time setting t should be set to meet any general protection requirements as discussed in Section 2 10 These normal settings should also be used in the second setting group group 2 W hen the generator is shut down a normally closed circuit breaker auxiliary contact can be used to prevent tripping and alarm initiation by the under voltage protection Service M anual R5942B LG PG111 Chapter 3 Page 60 of 75 This arrangement will be different from that highlight
121. yellow Alarm LED flashes when the relay operates Check ALARM Protection 27UV appears on the display ignore other alarms Stop current injection and reset all alarms on the relay Record the operating time obtained O perating time t setting with a 5 tolerance 10 to 40mS O peration of output relays Repeat the previous injection to operate the 27 Under Voltage Check the operation of the output relays against the scheme logic settings Record the output relays operated Restore the original Scheme Logic settings if changed Over voltage A two stage element three phase over voltage detection function is provided It primarily used for the back up of the speed control governor and the automatic voltage regulator W hen severe over voltage occurs the high set element can be set to provide fast operation Enable the 59 O ver Voltage protection only If necessary change the scheme logic input matrix so that only the 59 will cause the output relays to operate N ote the protection function will operate only when the voltage at the V and V inputs are both above the setting V gt M easurements Inject rated voltage from into the V input terminals B25 B26 Record and check the voltage injected and the voltage measured by the relay Repeat for the V _ input terminals B27 B28 Allowing 3 tolerance Characteristic and operating time Record the over voltage settings V gt t gt V gt gt and t gt gt Me
122. 0000 1 000000000000000 Table 46 The LG PG111 s Test Functions Section of its menu Various test facilities The section contents are shown as if the alternative setting group was enabled W hen itis disabled the bracketed group identifier 1 amp 2 will disap pear along with the group 2 cells This is noted in the description of each cell below N one of these settings are included in the remote system setting transfer Service M anual LG PG111 20 1 20 2 20 3 20 4 20 5 R5942B Chapter 6 Page 71 of 91 Lamp test Allows the operation of the front panels LED s to be checked Front Panel Remote Access 3 l ee Test aoe Test Off Press SET For Lamp Test On Lamp Test Table 47 States of the Lamp Test cell when activated the lamp test inverts the current states of the trip alarm and out of service LED s for approximately 2s the relay healthy led will remain on momentarily and then extinguish after the completion of the test in about 2s the LED s return to their normal states and the cell returns to it s off state Relay test Allows the relay output contacts to be checked This cell can only be changed when the scheme output has been inhibited in the Auxiliary Functions Section W ith the scheme output inhibited any desired combination of relay outputs can be operated simply by setting up the appropriate bit pattern Resetting the cell provides a
123. 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 R5942B Chapter 6 Page 79 of 91 OUTPUT 10000000 10000000 10000000 10000000 10000000 10000000 10000000 10000000 10000000 10000010 10000011 10100000 00000100 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 MATRIX 0000001 0000010 0000100 0001000 0010000 0010000 0100000 0100000 1000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 Service M anual R5942B LG PG 111 8 4 Chapter 6 Page 80 of 91 Event Records Three options are available to specify the number of records to be printed The options are to print10 25 or All Records W hen the number of records available is less than the number specified t
124. 0s to 60ms in 0 25ms increments Normally this setting should be Os butit can be increased when using half duplex communications adapters such as RS232 to twisted pair RS485 or RS232 to half duplex optical fibre The delay allows the transceivers used in such devices to switch between transmitting and receiving This setting is not available when the remote communications are disabled 18 5 Baud rate Defines the transmission and reception speed for the IEC870 communications modes in bits per second Can be set to 600 1200 2400 3600 4800 7200 9600 14400 or 19200 Baud This setting is only available for the IEC870 communications modes The term adapter is used here for a device which converts between physical commu nications mediums This is distinct from a communications protocol converter which may well change the communications medium as part of its protocol conversion An adapter has no knowledge about what is being transmitted whereas a protocol converter must have and therefore requires no transmit delay by the LG PG 111 Service M anual LG PG111 7 20 Disturbance recorder Item Front Panel Remote Access le 19 0 DISTURBANCE Disturbance Recorder RECORDER 19 1 Recorder Status Recorder Status Running Running 19 2 Data Capture Data Capture Raw ADC Samples Raw ADC Samples 19 3 Post Trigger Post Trigger Cycles 32 Cycles 32 po 19 4 Analogue Analogue
125. 111 s System Data Section of its menu This section contains basic information about the LGPG111 1 1 Password A four character upper case password can be entered in this cell If the entered password matches with the one stored in the LGPG111 all the password protected cells in the relay are unlocked these settings can now be altered If the entered password does not match the setting is rejected and password protected cells remained locked Password protection can be re applied by resetting this cell Additionally after a period of inactivity the relay automatically re applies password protection In the password unlocked state the password can be changed by entering a new password Care should be taken not to change the password inadvertently and equally a new password should be securely noted If the password to the LGPG111 is lost ALSTOM T amp D Protection amp Control Limited can be contacted for a backup password which will unlock the password protection and allow a new password to be entered Service M anual LG PG111 1 2 1 3 1 4 1 5 1 6 1 7 1 8 R5942B Chapter 6 Page 27 of 91 There is a password lock for each user interface system a password entered in one system unlocks only that system and not both An eventis logged for both the removal and re application of password protection for each access system The LGPG111 is normally supplied with a default password of AAAA Description
126. 2 For Imean bias max gt s2 ldiff gt K2Xlmea n bias max Is2 x K2 z K1 Isl The characteristic is shown in Figure 8 Service M LG PG111 3 2 3 2 1 anual R5942B Chapter 4 Page 18 of 50 Differential Current Percentage Bias K2 Percentage Bias K1 MOO TRIP Max Mean Bias Current Figure 8 Generator differential biased characteristic The recommended settings as explained in the Application N otes are shown below Isl 0 05xIn K1 0 Is2 1 2xIn K2 150 Stator earth fault 51N General description The stator earth fault protection function uses current from the I input as the operating quantity The function consists of a low set element and a high set element The low set element can be set to either a standard inverse or a definite time characteristic The high set element has a definite time characteristic which can be set to instantaneous Both elements are inherently immune to third harmonic currents due to the response of the Fourier filter Selectable by a setting rack Inhibit LS Timer S1N Inhibit gt inhibit HS timer Input Inhibit LS amp HS Timers S t Figure 9 Logic of the 51N inhibit input Service M anual R5942B LG PG111 Chapter 4 3 2 2 Page 19 of 50 A logic input 51N Inhibit is available to inhibit the low set timer the high set timer or both A setting is provided to conFigure this W hen the input is energised it will force the selected timer
127. 2B Chapter 6 Page 23 of 91 The menu in the LG PG111 is divided into several sections Each section represents some aspect of the relay and a brief summary of each is provided below Sections 7 0 to 16 0 relate to the protection As shown the second alternative setting group is disabled W hen the second setting group is enabled each of the sections 7 0 to 16 0 is duplicated one for each setting group which are ordered in pairs The group identifier is appended to each section title and to each cell on the front panel For example the section contents will appear as eL Front Panel 8 0 GENERATOR Generat DIFFERENTIAL 1 E GENERATO ceesa DIFFERENTIAL 2 9 0 EARTH FAULT Earth PROTECTION 1 Ma 4 9 0 EARTH FAUL Earth PROTECTION 2 Ea Faul Faul Dif Dif ferent ferent Protec Protec ial ial tion tion Remote Access 1 Table 4 Illustration of the appearance of the menu contents list when the alternative setting group facility is enabled Service M anual LG PG 111 R5942B Chapter 6 Page 24 of 91 And the contents of say the Generator Differential group 1 section as 8 0 ll Remote Access GENERATOR Generator Differential 1 DIFFERENTIAL 1 Front Panel 87G Gen
128. 3 44 44 44 46 46 46 48 48 48 48 49 52 Service M anual R5942B LGPG111 Chapter 9 Page 8 of 52 Service M anual R5942B LGPG111 Chapter 9 Page 9 of 52 COMMISSIONING TEST RECORD FOR THE LGPG TESTED AS ONE UNIT Date Le ee es eae eS ee ROE Ree ee Re ee Tested by Nae Se a a ee Oe Company anne nnn aa Site Slee a SOE ee SOR ee ta Generator Circuit EOE E EA e AAA A E E T Model number Saal nner Vx 1 c Vx 2 ne ee EDERE Jamie In pee Commissioning Preliminaries Relay model number rating and module reference correct ES NO CT shorting switches in case checked YES NO Earth connection to case checked YES NO Insulation checked YES NO External wiring checked to drawing YES NO Auxiliary Power Supply Test Polarity of Vx 1 and Vx 2 checked YES NO Measured VxX 1 V Vx 2 0 V Correct YES NO Relay power supply failure alarm checked YES NO LED s tested YES NO Secondary Injection Tests Service settings applied YES NO M odel and serial number correct in menu YES NO System frequency correct in menu YES NO CT and VT ratios correctly entered YES NO Primary secondary display value selected correctly YES NO Alternative setting group enabled YES NO Secondary injection tests applied to group 1 or 2 1 2 Service M anual R5942B LGPG111 Chapter 9 Page 10 of 52 Current based protection Measurement checks Input Injected current Measured value
129. 4 multi modular hardware Together with the next 4 digits they specify the type of the module The next 3 characters represent a sequential number and vary according to minor variations such as the rating of the module The last letter is a design suffix letter The position of a module in the equipment is designated by a number Module 1 is in the leftmost position of the top sub rack as viewed from the front The rest of the modules are numbered sequentially from left to right The module number is marked on a strip fitted into the top front extrusion of the module The case also has numbered strips which indicate the position of each module Scheme numbering W here an auxiliary sub ack forms part of a more complex scheme i e in conjunction with other ALSTOM T amp D Protection amp Control Limited equipment a coding comprising 2 letters and 10 numbers is used The related scheme or system diagrams are coded 12 L00 000 000 or 14 LOO 000 000 The two digits 12 and 14 denote tender or contract diagram respectively The 4th letter denotes the type of relay casing used L represents the M4 multi modular case system This and the digits following the coding are required for complete identification of the scheme Mechanical layout numbering The case terminals and their functions are shown on the external connection diagram or application diagram These are specified by a drawing number of the form 10 LGPG111 nn W here 10 indicate
130. 5 4 OB x0 9 5 6 R5942B Chapter 6 Page 91 of 91 Logic input operation alarm messages This type of alarm is caused by the energisation of the optically isolated logic inputs However the Clock Sync and Group Select logic inputs are excluded The Clock Sync input is expected to occur on a regular time base and the two Group Select logic inputs are recorded by group selection events or by a group select input failure event fri Display Logic Input Energisation ARM Logic I P Under Voltage and Under Frequency inhibit 27 81U Inhibit ARM Logic I P Voltage Dependent Overcurrent inhibit 51V Inhibit ARM Logic I P Stator Earth Fault timer inhibit SIN Inhibit sar ogic I P A logic input with the definable label of Inout 6 There ne are eight scheme configurable logic inputs Table 53 Logic input energisation Alarm messages Relay output operation alarm messages This type of alarm is caused by the operation of relay outputs Display Relay O utput Operation ee ee O P Relay inoperative contact A fatal error occurred Check Jo opener Ye with other alarm messages to find out the cause of the error ae N O P A relay output with the definable label of O utput 1 There ees are fifteen scheme configurable relay outputs Table 54 Relay output Alarm messages Diagnostic e
131. 5Hz only To track beyond this range a zero crossing technique is also implemented to complement the tracking algorithm This is applied when the relay is initially set up at nominal frequency to track to a low frequency condition such as when the generator is running up The frequency tracking algorithm uses one of three possible inputs as the reference source Initially the algorithm checks the V input followed by the V and inputs until a suitable signal to track is found If the tracking signal fails the algorithm will automatically switch to the next best input with the voltage inputs taking preference over the current input The minimum tracking threshold for the voltage signals is 7V and 0 05xIn for the current signal W hen all three signals fail the relay assumes a no input situation and automatically disables the under voltage under frequency and low forward power protection functions Error compensation Apart from errors due to analogue to digital conversion as mentioned earlier there Service M anual R5942B LG PG111 Chapter 4 Page 16 of 50 are other types of error conditions related to the signal conditioning for which soft ware compensation techniques are used These errors are 1 Component tolerance errors in the analogue input circuitry These consist of errors from the input transformers the anti aliasing filters the sample and hold amplifier and the ADC internal voltage reference An overall error of
132. 6 SECONDARY INJECTION FOR TESTING THE LGPG111 AS ONE UNIT W hen testing the relay as one unit it is necessary to ensure that each of the three Sections of the relay are functioning correctly and within the acceptable tolerances The three Sections can be described as The current and voltage inputs with their associated analogue to digital conversion hardware and the digital inputs The central processing unit comprising of the microcomputer I O bus power supplies measurements timers user interface internal diagnostic systems and the remote communications The output contacts and their relation to the scheme logic The tests that follow are designed to test the first two of these Sections the tests for the output contacts are given in section 9 of this chapter At the completion of the following tests the instructions given in section 8 Logic inputs section 9 Contact tests and section 10 Scheme logic tests should be carried out N ote the tolerances quoted throughout this section are the acceptable limits of the relay s operation and as such do not include any allowance for instrumentation errors The commissioning engineer should make suitable adjustments to the tolerances based on the accuracy of the measuring test equipment used Current based protection The following instructions are for the testing the functions that are current based The functions that are exclusively current based ar
133. 6 FEEF FFE i335 ereqoas og hbeeee Sate BHMMASON A eHnnHoe FSSSLohh ogoagdddd BERR P ER RRREOE RR PEE EH SSeS es sg ceo ee EEC SEES PS SPEECH PEE PH EEE EEHEHE tase E EEEE HERH EEEH EEEE EEEIEE EEEE EEEE Latch outputs CTO OOOO Fault record trigger LOOO OCO alarm trigger OOOO O L10 L11 L12 L13 L14 L15 L16 L17 L18 L19 L20 L21 L22 L23 L24 L25 L26 L27 L28 L29 L30 L31 Service M anual LGPG111 Signatures Commissioning Engineer Date R5942B Chapter 9 Page 52 of 52 Customer W itness Date
134. 9 8ms_ 8ms 10 8ms 8ms 11 2 ms 12 2 ms 13 2 ms 14 2 ms 15 2 ms Table 1 Relay output operating times Service M anual R5942B LG PG 111 Chapter 4 Page 40 of 50 LATCHED OUTPUTS FACILITY A facility is available whereby the user can select individual relay outputs to be latched once they have operated The selection is done through the Latch O utputs setting in the Scheme Logic menu Section This facility is implemented in software Therefore when the relay loses its auxiliary power the latched outputs will reset However the state of the latched outputs is stored in non volatile EEPROM memory W hen the auxiliary power is re applied the previously operated and latched contacts will be latched again The operation of a latched output will always cause a Relay operation alarm to be generated The output can be reset in two ways 1 By the alarm scan process on the front panel After all the alarm messages have been accepted the Reset key will reset all the alarms and the latched outputs 2 By the relay alarms cell in the menu This cell allows alarms and the latched outputs to be reset LOGIC INPUT ASSIGN MENTS The LG PG111 has fourteen optically isolated logic inputs Inputs 0 to 5 are located in the Analogue and Status Input Module and Inputs 6 to 13 are located in the Status Input M odule Inputs 0 to 5 are assigned with specific functions as outlined in Table 2 Logic Input Description
135. 942B Chapter 6 Page 3 of 91 Oo Co O N N O NT WI 10 10 11 13 17 17 19 20 20 20 20 22 22 26 30 36 38 40 42 48 49 50 53 56 57 Service M anual LG PG 111 7 14 7 15 7 16 7 17 7 18 7 19 7 20 7 21 7 22 8 1 8 2 8 3 8 4 Oils 9 2 o33 9 4 9 5 oe 9 a2 9 5 3 JNA 9 59 9 5 6 Voltage protection N egative phase sequence Field failure Scheme logic Input output labels Remote communications Disturbance recorder Test functions Protection operation summary PRIN T REPO RT EXAM PLES System settings Protection settings Scheme logic Event Records SUMMARY OF FRONT PAN EL USER IN TERFACE MESSAGES Relay reset messages Power on diagnostic error messages Run time default display messages User interface operational messages Alarm messages Exceptional alarm messages N on volatile EEPROM memory error alarm messages Protection operation alarm messages Logic input operation alarm messages Relay output operation alarm messages Diagnostic error alarm messages R5942B Chapter 6 Page 4 of 91 58 59 60 61 64 65 67 70 73 75 75 77 79 80 82 82 83 84 85 86 86 87 90 91 91 91 Service M anual R5942B LG PG111 Chapter 6 1 Page 5 of 91 INTRODUCTION The LGPG111 has been designed with two principal means of allowing a user to interact with it there is a front panel interface and a remote communications access interface B
136. 994 Jan 01 Date 1994 Jan 01 By Date 1994 Jan 01 Time 00 00 03 Time 00 00 03 lt Time 00 00 03 Date 1994 Jan 01 2 Date 1994 Mar 23 5 Date 1994 Mar 23 Time 00 00 03 lt Time 00 00 03 lt Time 00 00 03 Each field when selected can be incrementally changed with the TandJ keys For example incrementing the month field steps through the months of the Date 1994 Jan 01 T Date 1994 Feb 01 Date 1994 Mar 01 Setting M ode Time 00 00 03 Time 00 00 03 Time 00 00 03 Figure 9 Example of the front panel menu browse procedure Setting the clock gt binary flag cell is one whose numeric value is displayed in base 2 However the cells numeric value is unimportant itis the pattern of 1 s and 0 s which is of signifi cance Each digit or bit is used to represent some form of 2 state binary selection In this sense each bitis treated as a flag which when set to a 1 indicates the pre scribed flag is set or on The function of the flags is indicated through the user inter face Service M anual R5942B LG PG111 Chapter 6 Page 15 of 91 Default Display Menu Contents Section Contents GENERATOR SYSTEM DATA Password PROTECTION gt E S etting M ode Password cell consists of four characters the gt and keys move between e Kk AK kK ok KKK E Password 3 Password x gt a Password ae lt lt me Password Each character when selected can be incrementally cha
137. ALARM Protection 51V OC A appears on the display where a is the phase designator for the phase under test Ignore other alarms Reset all alarms Record the operating time For the DT characteristic O perating time t seconds with a 5 tolerance L0mS to 40mS where tis the applied setting For the SI characteristic O perating time 10 03 x TMS seconds with a 5 tolerance 10mS to 40mS where TMS is the applied setting Service M anual R5942C LG PG111 Chapter 8 Page 40 of 66 7 8 3 Characteristic and operating time for controlled function Record the voltage controlled overcurrent settings Voltage rotation Vs K I gt TMS tRESET and the Definite Time DT or Standard Inverse SI characteristic applied The following tests should be applied to each phase element complete the tests for each element in turn Begin by testing phase A Current Pick up Level Voltage level The following connections will be required during these tests M easurement of I gt Signal designator LGPG111 Connections F A11 A12 Ib A13 A14 Ic A15 A16 Vab B25 B26 Vbc B27 B28 Vea B25 B28 Link B26 B27 Vab B25 826 Link B25 B28 amp B26B27 For the different voltage vector rotation setting inject the voltage as follows for each phase Voltage Phase A Phase B Phase C Rotation Inject Inject Inject Setting N one l gt into la 1 2x
138. ARIES 11 5 1 Choice of commissioning tests 11 5 2 N otes for secondary injection tests 12 5 3 Setting the relay 15 6 SECO N DARY INJECTION FOR TESTING THE LGPG111 ASONEUNIT 16 6 1 Current based protection 16 6 1 1 Measurement checks 16 6 1 2 Check of pick up value 17 6 1 3 Measurement of time delay characteristics 17 6 1 4 Fault record checks 18 6 1 5 Thermal curve characteristic 18 6 2 Voltage based protection 18 6 2 1 Measurements 19 6 2 2 Check of pick up value 19 6 2 3 Measurement of time delay characteristic 19 6 2 4 Measurement of frequency 19 6 2 5 Fault record checks 20 6 3 Power based protection 20 6 3 1 Measurement of phase angle 20 Service M anual R5942C LG PG 111 6 3 2 6 4 T 7 1 7 1 1 7 1 2 7 1 3 7 1 4 1 2 7 2 1 7 2 2 7 2 3 1 3 Tada 1 3 2 7 3 3 17 4 7 4 1 1 4 2 17 4 3 7 5 Js3kL 7 5 2 7 5 3 7 6 7 6 1 7 6 2 7 6 3 7 6 4 7 6 5 7 1 7 1 1 1 1 2 17 1 3 1 1 4 Chapter 8 Page 4 of 66 M easurement of Directional Boundary 20 Final checks 21 SECON DARY INJECTION FOR TESTING EACH FUNCTION ASA DISCRETE UNIT21 87G Generator differential 21 Sensitivity operating time and output relay tests 21 Measurement Checks 22 Bias characteristic 22 Fault record checks 23 32R Reverse power 23 M easurements 24 Characteristic and operating time 24 O peration of output relays 25 32LLow forward power 25 M easurements 25 Characteristic and operating time 26 O peration o
139. C LG PG111 Chapter 8 12 1 13 13 1 14 Page 65 of 66 Stability of sensitive directional earth fault There is no practical site procedure for checking the stability of Sensitive Directional Earth Fault element The polarity of CT s and VT s must be independently vindicated ON LOAD CHECKS Carry out these checks for which the generator should be on at least 10 full load as required Check the VT phase sequence by using a phase sequence indicator and measure the VT voltage on the relay panel terminal block Record the results Record the measurements on the relay in the Measurements 1 and M easurements 2 Sections and check they are correct Check that la Diff lb Diff and Ic Diff measured on the relay are less than 10 of the mean bias current measured by the relay Check that I2 the negative phase sequence current measured by the relay is not greater than expected for the particular installation Check that the active power and reactive power measured by the relay are correct Phase angle compensation for the power measurement The LGPG111 provides a setting for phase angle compensation in the Power Protection Section The default setting for the Compensation Angle is 0 Altering this compensation angle setting is not recommended unless an accurate phase angle meter is available W ith an accurate measurement of the generator s phase angle note the difference between it and the relay s phase angle measu
140. CA degrees where RCA is the setting applied to the relay Record and check the current and voltage measured by the relay allowing 3 tolerance Accept and reset all alarms Measurement of residual W ith the connections and phase angle set as above inject 2xVep gt Volts into the relay Inject zero Amps into the relay and slowly increase the current to measure the pick up and drop off values for residual esiduay PICK up value Iresidual gt with a 5 tolerance drop off value 0 95 x lresidual gt with a 5 tolerance lagi Service M anual R5942C LG PG 111 7 5 2 Chapter 8 Page 30 of 66 M easurement of Vep gt W ith the connections and phase angle setas above inject rated current into the relay Inject zero Volts and slowly increase the voltage to measure the pick up and drop off values for V Stop injection and reset all alarms V pick up value Vep gt setting with a 5 tolerance V drop off value 0 95 xVep gt setting with a 5 tolerance Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check ALARM Protection 67N SDEF appears on the display ignore other alarms Reset all alarms Measurement of RCA W ith the connections and phase angle set as above inject 2xVep gt Volts and rated current into the relay Rotate the phase difference lagging to measure the phase angle when the relay picks up and drops off Rotate the phase difference leading t
141. Chapter 3 Page 34 of 75 accuracy as discussed in Section 2 6 1 The voltage restrained protection function should also co ordinate with outgoing feeder protection for a feeder fault under minimum plant conditions The most onerous case to consider is that of a close up three phase fault on a feeder where there would be almost a full voltage collapse seen by the LGPG111 W here co ordination is difficult to achieve and where KCGG KCEG feeder overcurrent relays are employed start contacts of the feeder overcurrent relays should be used to interlock operation of the LGPG111 voltage dependent protection function as described in Section 3 4 The protection function should be able to respond to a remote end fault on an outgoing feeder from the generator bus It will be assumed that where a step up transformer is being used it will also be an application where the LG PG 111 negative phase sequence thermal protection function would be set and enabled For this reason consideration will only be given to the detection of a remote end three phase feeder fault with the protected machine as the only source The relay primary operating current for a remote end three phase fault with the generator acting as the only source should be 50 of the relay current seen at the particular voltage level present for such a fault W ith the recommended setting for the lower voltage threshold Vs2 the relay current setting will be the base fault setting K I gt For
142. ERVICE LED is illuminated 3 Relay output module is faulty LED s No alarm or trip indications The alarm and fault triggers have not been set up in the Scheme Logic section of the menu O ut of service LED is on 1 The relay has been manually placed out of service by setting the scheme output status cell in the Auxiliary Functions section of the menu to Inhibited 2 The relay is in calibration mode Reset the relay or exit from the remote access calibration software O ut of service LED is on and relay healthy LED is off This happens when a fatal error has been detected by the self monitoring The protection has been disabled See the Self M onitoring section of chapter 4 Second setting group not displayed The second setting group has not been enabled Set the second setting group cell to Enabled in the Auxiliary Functions section of the menu Alarms Too few or too many alarms Check the setting of the alarm trigger cell in the Scheme Logic section of the menu Also note that outputs defined as latched or those specified to generate a fault record will also generate alarms Cannot reset the latched outputs The condition which operated a latched output is still present Service M anual R5942C LG PG111 Chapter 7 4 6 4 7 4 7 1 4 1 2 4 1 3 4 7 4 4 8 Page 11 of 14 Event records Event and fault records have been lost The LG PG 111 has a continuous event recorder but with
143. F Enabled Enabled fos ee 7 5 51V Overcurrent 51V Overcurrent Enabled Enabled 7 6 32R Reverse Pwr 32R Reverse Power Enabled Enabled 7 7 32L Low Fwd Pwr 32L Low Forward Power Enabled Enabled 7 8 81U 1 Under Freg 81U 1 Under Frequency Enabled Enabled ie atl 7 9 81U 2 Under Freg 81U 2 Under Frequency Enabled Enabled a oe 7 10 810 Over Freq 810 Over Frequency Enabled Enabled 7 11 27 Under Voltage 27 Under Voltage Enabled Enabled 7 12 59 Over Voltage 59 Over Voltage Enabled Enabled 7 13 60 Volt Balance 60 Voltage Balance Enabled Enabled 7 14 46 Neg Phase Seq 46 Negative Phase Sequence Enabled Enabled 7 15 40 Field Failure 40 Field Failure Enabled Enabled C Table 22 The LGPG111 s Protection Function Status Section of the menu Provides a quick summary of which protection functions have been enabled and disabled It is not possible to change a protection functions status here Service M anual LG PG111 7 9 Generator differential 8 0 8 1 8 2 8 3 8 4 8 5 GENERATOR DIFFERENTIAL 87G Gen Diff Enabled 87G Gen Diff Isl 0 05 A 87G Gen Diff Kl 0 87G Gen Diff Is2 1 20 A Front Panel 87G Gen Diff K2 150 R5942B Chapter 6 Page 49 of 91 Remote Access Generator Differential 87G Generator Differential Enabled Isl 0 05 A Kl 0 ae Is2 1 20 A K2 150
144. G 111 is required Error AutoText entry not defined provides a Suitable description of the scheme logic Then from the setting schedule scheme logic input scenarios can be devised along with their expected scheme outputs The test proceeds by setting each input scenario and checking the output corresponds with the expected result Example scheme logic tests Figure 2 illustrates the various types of logical arrangements which the LGPG111 s scheme logic is capable of providing Field Failure Voltage balance Sensitive DEF Voltage balance Block a balance Comp SYN 2 Neutral Displacement o7N 33 22nn weooStdd gisisFae eeereye LO 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 L1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 L2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 0 00 INPUT MATRIX O UTPUT MATRIX Latched Outputs 0 0 0 0 0 0 0 0 O 0 0 0 0 070 Fault Record Trigger 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Alarm Trigger 0 0 0 0 0 0 0 0 Figure 2 illustrates the various types of logical arrangements which the LGPG111 s scheme logic is capable of providing Service M anual R5942C LG PG111 Chapter 8 Page 61 of 66 Figure 2 Illustration of p
145. I TW TL GENERATOR 87G Gen Diff DIFFERENTIAL Enabled I N N TH FAULT 51N Stator EF LECTION Enabled lj N i Figure 5 An illustration of the LGPG111 s menu organisation N ot complete 3A trip is defined by the fault record trigger from any of the 15 contact outputs An alarm is defined by the alarm trigger latched outputs and diagnostic exceptions Service M anual R5942B LG PG111 Chapter 6 4 1 3 4 2 Page 9 of 91 The yellow out of service LED is illuminated when the output contacts are inhibited by the scheme output cell Under this condition all the protection alarm recording and front panel indication functions are performed normally All the relay outputs are however disabled This allows injection testing without the risk of tripping circuit breakers etc The green relay healthy LED is always on when the relay is functioning correctly but is switched off if the relay becomes faulty Under some failure conditions the relay will also illuminate the out of service LED Push buttons The front panel has seven push buttons consisting of 4 arrow keys T J lt a SET key an ACCEPT READ key and a RESET key The 4 arrow keys and the SET key are only accessible to the user when the transparent front cover is removed A key if continuously pressed will autorepeat The autorepeat rate rapidly increases to facilitate rapid selection this is partic
146. ION OP SUMMARY 21 1 21 2 21 3 87G Gen Diff A 0 21 4 87G Gen Diff B 0 21 5 87G Gen Diff C 0 21 6 51N gt Stator EF L 0 Re 51N gt gt Stator EF 0 21 8 59N 1 Neutral D L 0 21 9 59N 2 Neutral a 0 21 10 67N SDEF L 0 21 11 21 12 51V oc A 08 22 13 Siv oc B 21 14 51V oc c 0 22 15 32R Reverse Pwr 0 21 16 32L Low Fwd Pwr 0 21 17 81U 1 Under Freq 0 21 18 81U 2 Under Freq 0 ZELS 810 Over Freq 0 Protection Operation Summary 16 Aug 1994 16 02 58 218 87G Generator Differential 67 Phase A 0 Phase B 0 Phase C 0 51N gt Stator Earth Fault 0 51N gt gt Stator Earth Fault 0 59N 1 Neutral Displacement 0 59N 2 Neutral Displacement 0 Sensitive Directional EF 0 51V Overcurrent Phase A 0 Phase B 0 Phase C 0 32R Reverse Power 0 32L Low Forward Power 0 81U 1 Under Frequency 0 81U 2 Under Frequency 0 810 Over Frequency 0 Continued Service M LG PG111 anual R5942B Chapter 6 Page 74 of 91 Continued from previous page A Et oo 21 20 E Under Voltage 27 Under Voltage Low Set 0 21 21 eas 59 gt Over Voltage High Set 0 21 22 fe ere 59 gt gt Over Voltage 02 21 23 ee 46 gt PS Alarm 02 21 24 Re PS Thermal 46 gt gt NPS Trip Thermal 0 21 25 ka
147. M5 link 23 Interrupt amp DMA Select JM 6 13 14 RS232 Factory Test Interface Select JM7 Rear connection Front panel socket JM 8 Front panel socket N o link fitted M7 Figure 3 microprocessor amp serial communications module link positions Status Input Module GM0022 GM0111 Both modules use the same pcb which has two links that select the correct address decode for this module a course and fine address selection See Figure 4 for the Status Input M odule link positions Address Decode Coarse JM2 link 116 Fine JMI link 34 This connection is not available on the LG PG111 as the front panel socket is used by the remote communications Service M anual LG PG 111 6 4 6 4 1 6 4 2 6 4 3 ZH0928 ___ JM2 Vw m aa Figure 4 Status input module link positions Analogue and status input module R5942B Chapter 5 Page 22 of 23 The analogue and status input module will have one to two pcbs fitted that both have three link sets The pcb numbers are ZH1010 or ZH1017 The links are for address decoding interrupt DMA configuration and a calibration memory write protect See Figures 5 and 6 for the analogue and status input module link positions Address Decode JM2 Link 19 2 10 Interrupt amp DMA Select
148. Measured O perating Time Characteristic and Operating Time for Simple Function if applicable gt TMS treset SI or DT Measurement of I gt Phase Expected Pick up Measured Pick up Measured Drop off Measurement of O perating Time Characteristic Expected O perating Time M easured O perating Time Service M anual LG PG111 Fault Record Checks Fault records match injected faults Operation Of Output Relays Correct Operation Of Output relays N otes R5942B Chapter 9 Page 31 of 52 Service M LGPG111 anual R5942B Chapter 9 Page 32 of 52 46 Negative Phase Sequence Measurements Phass Phases Injected Current Injected Current Measured Current Measured Current ACE bic OO O c Characteristic And Operating Time For 46 gt NPS Alarm 2 gt p Measurement of 12 gt Phase Expected Pick up Measured Pick up Eo Current Current la s booo Jl a eS Measurement of O perating Time Phase Expected Operating Operating M Measured Operating perating o me 5 me C C Operation Of Output Relays For 46 gt NPS Alarm Correct Operation Of Output relays Characteristic And Operating Time For 46 gt gt NPS Thermal Trip I2 gt gt K tM AX tMIN Kreset Measurement of 12 gt gt Service M anual R5942B LGPG111 Chapter 9 Page 33 of 52 Phase Expected Pick up M easured Pick up Current Current 1a
149. Measured Pick up Measured Drop off Voltage Voltage Voltage Service M LGPG111 anual M easurement of V gt gt Expected Pick up Voltage Measured Pick up Voltage Measured Drop off Voltage M easurement of O perating Time t gt Expected O perating Measured O perating Time Time M easurement of t gt gt Expected Operating Measured Operating Time Time Operation Of Output Relays Correct Operation Of Output relays N otes R5942B Chapter 9 Page 38 of 52 Service M anual R5942B LGPG111 Chapter 9 Page 39 of 52 60 Voltage Balance Vs Measurement Checks Input Measured Voltage Vab Prot Vbc Prot Vab Comp Vbc Comp Injected Voltage Characteristic Checks for 60 VB Prot Input Expected Pick up Measured Pick up Measured Drop off Voltage Voltage Voltage Vab Vbc Characteristic Checks for 60 VB Comp Input Expected Pick up Measured Pick up Measured Drop off Voltage Voltage Voltage Vab Vbc Operation of Output Relays Correct Operation Of Output relays N otes Service M anual R5942B LGPG111 Chapter 9 Page 40 of 52 Input Status Checks Relay Terminal Input Status Results as expected Energized Displayed Relay output tests ContactName Or Relay Test Pattern Results As Expected N umber Entered
150. N Neutral Displacement Disabled Ve gt 1 V Eis 1 0 s Eza Os t2RESET Os 67N Sensitive Directional EF Disabled Tresidual gt 20mA RCA 0 deg Vep gt 5 V Tep gt 20mA Voltage Dependent Overcurrent 51V Overcurrent Enabled Function Voltage Controlled Voltage Vector Rotate None Vs 34 V K O25 Characteristic Definite Time I gt 1 00 A ti 13 52 8 tRESET Os Power Protection Compensation Angle 0 deg 32R Reverse Power Enabled P gt 0 20 W E Pickup 0 5 s tDO Dropoff Os 32L Low Forward Power Enabled P lt 0 20 je Pickup 0 5 s tDO Dropoff Os Service M anual LG PG111 R5942B Chapter 6 Page 78 of 91 Frequency Protection 81U 1 Under F1 lt 45 00 El 1 0 1U 2 Under F2 lt 45 0 E2 lee 10 Over F gt 55 0 t O Z S p Z Os 8 0 ni HZ S Voltage Pro 27 Under Voltage V lt 30 V E 4 0 s 59 Over Voltage v gt LOS V t gt O28 v gt gt 130 V t gt gt Os 60 Voltage Balance Vs gt 20 V Frequency Frequency Frequency Enabled Enabled Enabled tection Enabled Enabled Enabled Negative Phase S 46 Negative Phas guenc Enabled 46 gt gt NPS Thermal I2 gt gt O 50 A K 2 tMAX 2000 tMIN 2 00 Kreset 2 46 gt NPS Alarm I2 gt 0 50 A t gt 2s UE W UE D Field Failure 40 Field Failure Sequenc Trip Enabled Xa Offset Xb
151. NING TEST RECORD FOR THE LG PG TESTED AS ONE UNIT Commissioning Preliminaries Auxiliary Power Supply Test Secondary Injection Tests Current based protection M easurement checks Check of pick up value M easurement of time delay characteristics Fault record checks Thermal curve characteristic Voltage based protection M easurements Check of pick up value M easurement of time delay characteristic M easurement of frequency Fault record checks Power based protection Measurement of phase angle M easurement of RCA Input Status Checks Relay output tests Relay inoperative alarm Scheme logic tests COMMISSIONING TEST RECORD FORTHE LGPG111 TESTED AS DISCRETE RELAYS Commissioning Preliminaries R5942B Chapter 9 Page 3 of 52 11 11 11 11 11 11 11 11 11 12 12 13 13 16 16 16 Service M anual LGPG111 Auxiliary Power Supply Test Secondary Injection Tests 87G Generator Differential Tests Sensitivity and Operating Time M easurements Bias Characteristic Fault Record Checks 32R Reverse Power M easurements Characteristic Checks O peration of O utput Relays 32LLow Forward Power M easurements Characteristic Checks O peration of O utput Relays 40 Field Failure M easurements Characteristic and O perating Time O peration of O utput Relays 67N Sensitive Directional Earth fault Measurements and Characteristic For V Measurements and Characteristic For O peration of O
152. R PROTECTION R5942A Chapter 1 Page 3 of 5 Service M anual R595942A LG PG 111 1 Chapter 1 Page 4 of 5 Introduction A number of protection functions are required to fully protect generators against the adverse effects of the different types of faults and abnormal operating conditions that might occur The exact forms of protection that are required are dependent on the type design size and purpose of the generating plant and on the form of power system which is to be supplied Traditional generator protection schemes have been made up of various discrete protective relays in conjunction with auxiliary relays and other scheme components A number of trip outputs are usually provided for initiating various plant actions depending on the type of protection operation Digital protective relay technology has been gaining widespread acceptance over recent years The benefits of standardised hardware multiple functions multiple hybrid characteristics other enhancing features and remote communications are well recognised It is the cost benefit and the fact that such power system devices can be made more useful for purposes beyond protection that is now becoming recognised outside the discipline of protection engineering W hen digital technology is applied to generator protection a number of protection functions can be integrated into a single relay This approach produces a reduction in both the physical size of the protection
153. RES 8 3 1 Power supply checks 8 3 2 M ain microprocessor checks 8 343 Front panel checks 8 3 4 Relay output module checks 8 3 5 Logic input status checks 8 3 6 Analogue input checks 9 3 7 Communications checks 9 4 PRO BLEM SOLVING 10 4 1 Password lost or not accepted 10 4 2 Relay tripping 10 4 3 LED s 10 4 3 1 No alarm or trip indications 10 4 3 2 Outofservice LED is on 10 4 3 3 Outof service LED is on and relay healthy LED is off 10 4 4 Second setting group not displayed 10 4 5 Alarms 10 4 5 1 Too few or too many alarms 10 4 5 2 Cannot reset the latched outputs 10 4 6 Event records 11 4 7 Disturbance recorder 11 4 7 1 New settings have been rejected 11 4 7 2 Cannot access disturbance records at the front panel user interface 11 4 7 3 No disturbance record generated or records lost 11 4 7 4 The length of the disturbance record is shorter than expected 11 4 8 Inaccurate measurements 11 Service M anual LG PG 111 4 9 4 10 4 11 4 11 1 4 11 2 4 11 3 Problems with printing Relay contact test Communications Cannot establish communications Communications fails G eneral R5942C Chapter 7 Page 4 of 14 12 12 13 13 14 14 Service M anual R5942C LG PG111 Chapter 7 1 1 1 2 Page 5 of 14 INTRODUCTION This chapter covers two distinct areas of fault finding Isolating faulty hardware modules within the LG PG111 and providing solutions to common operational problems Proble
154. RO TECTION FUNCTIONS Generator differential 87G G eneral description Bias current calculation Settings and protection characteristic Stator earth fault 51N G eneral description Settings and protection characteristic N eutral displacement 59N G eneral description Settings and protection characteristic Sensitive directional earth fault 67N G eneral description Settings and protection characteristic Voltage dependent overcurrent 51V G eneral description Settings and protection characteristic Voltage vector transformation R5942B Chapter 4 Page 3 of 50 WO Oo O OO CO N N O N N N NY NY NN NY NN FP FPP YP PP PP PP PP PP eB w N e FF OG OG OW OG OG Oo woe woONSH INN INN OO A A BYP FP FS OC Service M anual LG PG 111 3 6 3 6 1 3 6 2 3 7 Jekel 3 7 2 3 8 3 8 1 3 8 2 3 9 3 9 1 3 10 3 10 1 3 10 2 3 11 Ped Lely 3 11 2 3 12 3 13 4 4 1 4 2 4 2 1 4 2 2 4 2 3 7 1 1 2 1 3 1 4 7 5 Reverse power and low forward power 32R amp 32L General description Settings and characteristic N egative phase sequence thermal protection 46 General description Settings and characteristic Field failure 40 General description Settings And Characteristic Under and over voltage 27 amp 59 Settings and characteristic Under and over frequency 81U amp 810 General description Settings and characteristic Voltage balance 60 General description Settings and ch
155. Service MANUAL INTEGRATED GENERATOR PROTECTION Retay Type LGPG111 R5942B ALSTOM Service MANUAL INTEGRATED GENERATOR PROTECTION Retay Type LGPG111 R5942B HANDLING OF ELECTRONIC EQ UIPM ENT A person s normal movements can easily generate electrostatic potentials of several thousand volts Discharge of these voltages into semiconductor devices when handling electronic circuits can cause serious damage which often may not be immediately apparent but the reliability of the circuit will have been reduced The electronic circuits of ALSTOM T amp D Protection amp Control Ltd products are completely safe from electrostatic discharge when housed in the case Do not expose them to the risk of damage by withdrawing modules unnecessarily Each module incorporates the highest practicable protection for its semiconductor devices However if it becomes necessary to withdraw a module the following precautions should be taken to preserve the high reliability and long life for which the equipment has been designed and manufactured 1 Before removing a module ensure that you are atthe same electrostatic potential as the equipment by touching the case Handle the module by its frontplate frame or edges of the printed circuit board Avoid touching the electronic components printed circuit track or connectors Do not pass the module to any person without first ensuring that you are both atthe same electrostatic potential Shaking h
156. TORAGE If products are not to be installed immediately upon receipt they should be stored ina place free from dust and moisture in their original cartons W here de humidifier bags have been included in the packing they should be retained The action of the de humidifier crystals will be impaired if the bag has been exposed to ambient conditions and may be restored by gently heating the bag for about an hour prior to replacing itin the carton Dust which collects on a carton may on subsequent unpacking find its way into the product in damp conditions the carton and packing may become impregnated with moisture and the de humidifier will lose its efficiency Storage temperature 25 C to 70 C CHAPTER 3 Appucation Notes Service M anual LG PG 111 Issue control R5942B Chapter 3 Page 2 of 75 Engineering document number 50005 1701 103 Issue Date Author Changes AP February 1995 Paul Hindle amp Original AlanTrow BP June1995 Dave Banham Minor corrections NPS protection notes updated to reflect change in LGPG111 functionality for version 18LG PGO O 2XXXEA onwards The N PS reset characteristic was an exponential decay now the thermal replica is used Kreset was the time constant of the exponential now itis the thermal capacity constant for cooling CT requirements expanded to include all _current inputs A July1995 Dave Banham Minor amendments and styles Publicity B Feb 1996 C
157. Testing facilities are available to aid commissioning and routine maintenance These facilities include testing of the front panel LED s relay outputs and scheme logic settings monitoring of the logic inputs and checking the progress of protection function operation Self checking and monitoring are also provided The LGPG111 monitors the power supply the analogue circuitry memory and the software and takes appropriate action once a failure is detected Self monitoring increases the availability of the relay by notifying the user immediately of any failure A simplified functional block diagram of the relay is shown in Figure 1 A detailed description of these functions is provided in the following Sections Service M anual R5942B LG PG111 Chapter 4 2 1 Page 7 of 50 Current And Voltage Data 5 Protection EY Processing Functions Communications Link Figure 1 Simplified functional block diagram of the LGPG111 relay INPUT SIGNAL PROCESSING Analogue inputs The LGPG111 has 17 analogue inputs consisting of 12 currentinputs and 5 voltage inputs Internal isolation transformers are used to scale the voltage and current signals from the generators CT s and VT s to a level compatible with the electronic circuitry These transformers also provide galvanic isolation between the relay and the generator plant The input signals are sampled sequentially through multiplexers using a sample and hold
158. Under frequency Voltage dependent overcurrent 87G Generator differential Only applicable with a parallel source present Figure 3 Protection of directly connected generator in isolation or in parallel Service M anual R5942B LG PG111 Chapter 3 Page 14 of 75 SS Z Penal S LGPG 111 T P Canala Sx H rma N Figure 4 LGPG 111 connections for a directly connected generator in isolation or parallel Service M anual R5942B LG PG111 Chapter 3 Page 15 of 75 Key 50 51 Instantaneous high set delayed HV overcurrent 51N HV standby earth fault KCGG140 50N _ HV breaker flashover enabled when Cb is open Transformer differential HV restricted earth fault Generating plant overfluxing Under voltage Low forward power Reverse power Unit or excitation Field failure transformer Negative phase sequence Stator earth fault Voltage dependent overcurrent Over voltage LGPG111 Neutral voltage displacement Voltage balance Overtrequency Under frequency Winding differential The unit transformer connection must be covered by a CT where the current to a LV fault would be high enough to cause operation of the winding differential protection function 87G The current operated stator earth fault protection function could be connected to a CT on the earthing transformer primary as shown and set to provide instantaneous high set protection Alternati
159. Vs l gt into lp 1 2xVs I gt into Ic 1 2xVs into Vab into Vpc into Veg Yd I gt into la 1 2xVs I gt into Ip I gt into Ic 1 2xVs into Vab into Vb Service M anual R5942C LG PG111 Chapter 8 Page 41 of 66 Inject the specified current and voltage to check the pick up and drop off values As there is a time delay associated with this function the Protection O peration Summary Section of the relay s menu can be used to determine the point at which this function starts to operate The Protection O peration Summary should indicate 0 when the Current injected is increased to the pick up point the displayed percentage will start to increase this is the pick up point the displayed value will rise from 0 and displays 100 when the time delay has expired Accept and reset all alarms pick up value I gt setting with a 5 tolerance drop off value 0 95xI gt setting with a 5 tolerance Repeat the tests for phases B and C Measurement of K I gt For the different voltage vector rotation setting inject the voltage as follows for each phase Voltage Phase A Phase B Phase C Rotation Inject Inject Inject Setting None K I gt into l 0 5xVs K I gt into Ip 0 5xVs K I gt into l 0 5xVs into Vab into Vc into Vca Yd K I gt into l 0 5xVs K I gt into Ip 0 5xVs K I gt into l 0 5xVs into Vab into Vap into Vc Inject the specified current and voltage to check the pick up an
160. a complete aluminium side plate which provides both mechanical strength and electrical screening for the electronic circuitry The side plates are electrically connected to the upper and lower plates by means of spring clips This internal screen is connected to the case ata single earthing point The arrangement gives a Faraday cage within the outer case This cage diverts all electromagnetic noise and interference from inter module coupling via a low impedance path to a single earthing point Service M anual R5942B LG PG 111 Chapter 5 Page 8 of 23 5 MODULE DESCRIPTIONS 5 1 Power supply Module Number GM0026 24V 30V amp 50V GM0097 110V amp 220V Five versions are available covering the following DC supply voltages N ominal O perative Range 24 27V 19 2 32 4 V 30 34V 24 40 8 V 48 54V 38 4 64 8 V 110 125V 88 150V 220 250V 176 300V Table 4 Power supply voltage ranges and withstands The function of the module is to supply four internal DC voltage rails from the single auxiliary DC input supply The module is of a switched mode power supply design and the output rails are fully isolated from the input External connections are made via a 28 way MIDOS connector The power supply output rails are distributed to the other modules in the equipment via the I O bus The four internal voltage rails are 6 5V 19 5V 19 5V and 24V The 6 5V rail is regulated to 5V locally in each of the modules to power logic circuitr
161. activity Timer Inactivity Timer 30 min 30 min 2 14 SEF TimerInhibit Stator EF Timer Inhibit Disabled Disabled 2 15 Clock Sync Clock Synchronised Disabled Disabled 2 16 Default Display Default Local Display Title Title Table 9 The LGPG111 s Auxiliary Functions Section of its menu This section contains a number of cells providing status information about the LG PG 111 and a number of miscellaneous cells controlling some configuration aspects of the relay Service M anual R5942B LG PG111 Chapter 6 Page 31 of 91 2 1 Date amp time The Current value of the LG PG111 s real time clock The cell is settable N ote that the format of the date amp time on a remote access system is not governed by the relay The remote access setting transfer does not include this cell 2 2 Logic input status A 14 bit binary flag representation of the optically isolated logic inputs to the relay W hen an input is energised its flag bit will show as a 1 otherwise it will show as a 0 This cell is duplicated in the Auxiliary Functions Section The bits are summarised in Table 7 page 28 2 3 Relay output status A 16 bit binary flag representation of the relay output status The LGPG111 has 16 output relays An energised relay is shown by a 1 and de energised by a 0 This cell is duplicated in the Auxiliary Functions Section The bits are summarised in Table 8 page 29 2 4 Protectio
162. ad machine protection scheme logic for group 1 setting Service M anual R5942B LG PG111 Chapter 3 Page 62 of 75 CB Open input 6 Relay 7 Breaker Flashover t gt O0s 51N gt gt __ Input 6 Figure 23 Breaker flashover protection KCGG110 Neutral current input K Bus communications Block lo gt gt Generator circuit breaker 52a contact Figure 24 Blocking of additional KCGG110 earth fault element If instantaneous neutral current detector operation occurs when the generator circuit breaker is open breakerfailure back tripping logic should be initiated where breaker fail protection is provided or the trip rail of the busbar protection should be energised 3 3 Over fluxing protection W hen the ratio of per unit generator terminal voltage magnitude to per unit frequency exceeds 1 0 the generator and associated transformers step up unit excitation supply and voltage transformers will become over fluxed Since these items of plant will be operated close to their core saturation levels to keep size and cost to a Service M anual R5942B LG PG111 Chapter 3 3 4 Page 63 of 75 minimum even moderate over fluxing in excess of 1 05 per unit can lead to core saturation and an increase in flux levels through unlaminated plant components that are not designed to pass significant levels of flux e g core bolts of traditional transformer designs The resulting eddy currents in such components will
163. affected by the line VT ratios Line VT ratio Scales the line to line voltage measurements This scaling affects the power settings and measurements the under and over voltage protection and the field failure impedance settings The field failure impedance settings are also affected by the value of the phase CT ratios The power settings and measurements are also affected by the sensitive la CT ratio Comparison VT ratio Scales the comparison voltage measurement The comparison voltage is used by the voltage balance protection function to ascertain the validity of the line voltage measurements Since the voltage balance protection is only concerned with the differential voltage between the two sets of measurements its setting is not affected by these scaling values Service M anual LG PG111 7 5 4 0 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 4 9 4 10 4 15 MEASUREMENTS 1 Item Front Panel a E 1 Ia OA Ib OA TE OA Vab 0 V Vbc 0 V Vca 0V Ie OA Ve 0 V I Residual OA T2 OA Active Power Aph OW Reactive Power Aph 0 VAr Phase Angle Aph 0 deg Frequency 0 Hz Remote Access Measurements 1 16 Aug 1994 16 02 58 218 Tas 0 Ib 0 Aion 0 Vab 0 Vbc 0 Vea O Les 0 Ve O I Residual 0 EZ 0 Active Power Aph 0 hr aeeennee Power Aph 0 Phase Angle Aph 0 Frequency 0 R5942B Chap
164. ake co ordination with local feeder overcurrent protection more difficult if this is not already a problem Reverse power and low forward power protection functions 32R 32L Summary e Reverse power protection Detects active power flow into the generator The level of power required to motor the generator will depend on the type of prime mover A high sensitivity current input is used to monitor the system power This may be connected to the main system protection CT s or for applications which require a sensitive setting the input can be driven from a high accuracy measurement CT A compensation angle setting is provided to compensate for CT and VT phase errors A time delay typically 5s should be used to prevent operation of the protection during some system fault conditions and power system swings To detect fluctuating reverse power flow which could result from failure of a reciprocating prime mover a delay on drop off timer is available in addition to the delay on pick up timer Reverse power protection is blocked for currents exceeding 1 05In due to the sensitive nature of this protection function e Low forward power protection O perates when the forward power falls below the set level O peration can be instantaneous or time delayed Usually interlocked with non urgent protection to reduce over speeding of the generator following breaker operation for a non urgent fault The interlocking can be achieved using th
165. ample of these alarm scan operations is provided in Figure 6 W ith the relay s front cover removed two further ancillary key actions are possible The lt arrow key aborts the alarm scan and returns the menu to its default display The alarms are neither accepted nor cleared so the alarm display and LED will be as they were This key action is included principally to allow the alarm scan to be aborted as a quick way back to the default display when the relay is being demonstrated The J arrow key causes the alarm scan to jump straight to the confirmation stage This key action is included as an aid during repetitive testing Section 9 5 page 86 details the alarm messages Default Display Alarm Scan ALARM gt ALARM Protection ACCEPT 87G Gen Diff READ ACCEPT READ ALARM Relay O P Trip CB This text is user definable ACCEPT R EAD RESET To clear alarms ALARM lt ACCEPT READ RESET GENERATOR ALARMS The Still Active message occurs when PROTECTION Still Active notall the alarms can be reset ALARM lt lt ACCEPT READ Figure 6 Example of the front panel alarm scan procedure Menu scan The RESET and ACCEPT READ keys are used to scan the menu Since these two keys are accessible with the front cover fitted they provide a convenient means of reading the relay s settings It is not possible to change any se
166. amplifier The samples are converted into digital data with an analogue to digital converter ADC The LGPG111 uses a 12 bit ADC in bipolar mode thus providing a bit resolution of 11 bits plus sign The sample and hold amplifier has a gain switching facility with a x1 and x8 gain selection which effectively increases the bit resolution from 11 to 14 bits There are two main sources of error associated with the analogue to digital conversion process The first occurs when the input signal is larger than the full scale range of the ADC input In this case the ADC will saturate and will produce a clipped waveform Another type of error is digital quantization error Since the signal after data conversion is represented by the nearest quantizing level there can be a conversion error of up to Isb least significant bit This error is significant only when the input signal is small W hen determining the dynamic range of an input itis necessary to consider the minimum and the maximum signal levels which the relay is required to measure accurately The analogue inputs are separated into groups based on their measuring function Different types of input transformers are used in each group to optimise the protection performance The 12 current inputs are all designed to make full use of the gain Service M anual R5942B LG PG111 Chapter 4 rae te Page 8 of 50 switching facility to maximise the effective dynamic range For the voltage inputs th
167. and 300V AC or DC Carry continuously 5A AC or DC Break AC 1250VA DC 50W resistive 25W YVR 0 04s with maxima of 5A and 300V Table 6 O utput relay contact ratings Each module has an address which is set by the positions of jumper links JM1 and JM 2 on the PCB The states of the output relays are controlled by an 8 bit data latch Data is written into the data latch when the address of the module is selected and the I O bus strobe signal is asserted by software The module takes the 6 5V and 24V supplies from the I O bus The 6 5V is regulated to 5V for logic circuitry on the board The 24V is used to drive the output relays All the output relays are held de energised during power failure or hardware reset conditions This prevents incorrect contact operations during power up power down and reset conditions W ith the exception of the relay inoperative alarm relay all the other output contacts are user definable through the scheme logic settings as described in chapter 4 Service M LG PG111 5 3 5 3 1 anual R5942B Chapter 5 Page 10 of 23 Relay Terminal Contact Drop 0 ff N umber Number Type Speed Speed 0 1 n o 3 common 8ms 8ms 5 n c 1 2 n o 4 common 8ms 8ms 6 n c 2 7 n o 8 ms 8 ms 8 3 9 n o 2 ms 2 ms 11 10 n o 2 ms 2 ms 12 4 13 n o 2 ms 8 ms 15 14 n o 2 ms 8 ms 16 5 17 n o 2 ms 8ms 19 18 n o 2 ms 8 ms 20 6 21 n o 2 ms 8 ms 23 22 n o 2 ms 8 ms 24 7 25 n o 2 ms 8
168. and whenever it is changed Consequential event messages added to Table 19 along with new real time clock set message ii Description cell in System Data is now settble Old description default display renamed as Title and a new description default display option added to display the Discription cell The header of printed reports now includes the description as well as the plant reference entries Some minor corrections Corrected Table 2 IEC870 character size specified incorrectly with 2 stop bits Added note to K Bus data that itis biphase FMO encoded Service M anual LG PG111 Contents 1 INTRO DUCTION 2 PHILO SO PHY 3 M ULTIPLE SETTIN G G RO UPS 4 FRONT PAN EL USER IN TERFACE 4 1 Description 4 1 1 Display 4 1 2 LED status indicators 4 1 3 Push buttons 4 2 Default display 4 3 M odes of operation 4 3 1 Alarm scan 4 3 2 Menu scan 4 3 3 Menu browse 5 REMOTE ACCESS USER IN TERFACE 5 1 Typical features of remote access software 5 2 Connections 6 SECURITY 6 1 Password protection 6 2 Remote Setting Change 6 3 Inactivity timers 7 MENU SYSTEM 7 1 M enu contents 7 2 System data 7 3 Auxiliary Functions 7 4 Transformer Ratios Per Measurements 1 7 6 Measurements 2 7 7 View records 7 8 Protection function status 7 9 Generator differential 7 10 Earth fault protection 7 11 Voltage dependent overcurrent 7 12 Power protection 7 13 Frequency protection R5
169. ands achieves equipotential Place the module on an antistatic surface or on a conducting surface which is atthe same potential as yourself 5 Store or transport the module in a conductive bag More information on safe working procedures for all electronic equipment can be found in BS5783 and IEC 147 0F If you are making measurements on the internal electronic circuitry of an equipment in service itis preferable that you are earthed to the case with a conductive wrist strap W rist straps should have a resistance to ground between 500k 10M ohms If a wrist strap is not available you should maintain regular contact with the case to prevent the build up of static Instrumentation which may be used for making measurements should be earthed to the case whenever possible ALSTOM T amp D Protection amp Control Ltd strongly recommends that detailed investigations on the electronic circuitry or modification work should be carried outin a Special Handling Area such as described in BS5783 or IEC 147 0F Number Chapter Name 50005 1701 001 Title Pages 90005 1701 101 General Description 50005 1701 102 Handling And Installation 50005 1701 103 Application N otes 50005 1701 104 Functional Description 50005 1701 105 Hardware Description 50005 1701 106 User Interface 50005 1701 107 Fault Finding Instructions 90005 1701 108 Commissioning Instructions 90005 1701 111 Commissi
170. anel should be isolated This will remove auxiliary voltages from the contacts and ensure that external plantis not operated inadvertently Set the Scheme O utput cell to Inhibited in the Auxiliary Functions Section The relay is now out of service and the yellow Out Of Service LED will be lit Enter a bit pattern in the Relay Test cell in the Test Functions Section and press the SET key to operate and latch the output relays N ote the outputs will latch in the closed position until the reset procedure is followed To reset the output relays replace the 1 s by 0 s and press the SET key Alternatively the cell can be reset to all 0 s by pressing the RESET key The following table illustrates the bit patterns required to operate an individual output relay Check normally open contacts close and normally closed contacts open with a continuity tester or multimeter O utput Relay to Bit Pattern Entered for be O perated Relay Test Relay 1 0000 0000 0000 0010 Relay 2 0000 0000 0000 0100 Relay 3 0000 0000 0000 1000 Relay 4 0000 0000 0001 0000 Relay 5 0000 0000 0010 0000 Relay 6 0000 0000 0100 0000 Relay 7 0000 0000 1000 0000 Relay 8 0000 0001 0000 0000 Relay 9 0000 0010 0000 0000 Relay 10 0000 0100 0000 0000 Relay 11 0000 1000 0000 0000 Relay 12 0001 0000 0000 0000 Relay 13 0010 0000 0000 0000 Relay 14 0100 0000 0000 0000 Relay 15 1000 0000 0000 0000 Table 4 O utput contact test patterns for single output opera
171. aracteristic Timer hold facility Integrating timer facility SCHEME LOGIC Basic principle Scheme logic examples Blocking with the voltage balance function Interlocking with the low forward power function Interfacing external devices RELAY O UTPUT O PERATING TIME LATCHED OUTPUTS FACILITY LO GIC INPUT ASSIGNMENTS Under frequency amp under voltage inhibit 27 amp 81U inhibit O vercurrent timer inhibit 51V timer inhibit Stator earth fault timer inhibit 51N timer inhibit Alternative setting group selection setting group select Real time clock synchronisation clock sync ALTERN ATIVE SETTING GROUP NON PROTECTION FUNCTIONS R5942B Chapter 4 Page 4 of 50 24 24 25 27 27 27 29 29 29 31 31 32 32 33 33 33 34 34 34 35 35 37 37 37 39 39 40 40 41 41 41 42 42 42 43 Service M anual LG PG111 9 1 M easurements 9 2 Event recording 9 3 Fault recording 9 4 Record retrieval mechanism 9 5 Alarm indication 9 6 Disturbance recording 9 7 Real time clock 9 8 Test facilities 9 9 Print functions 9 10 Self monitoring 9 10 1 Power on diagnostics 9 10 2 Runtime and background self monitoring 9 11 Cold and warm resets R5942B Chapter 4 Page 5 of 50 43 43 44 45 45 45 46 47 48 48 48 48 50 Service M anual R5942B LG PG 111 1 Chapter 4 Page 6 of 50 INTRODUCTION The design of the Integrated Generator Protection Relay LGPG111 is based entirely on n
172. arth fault protection function and as the current polarising signal for the sensitive directional earth fault protection function The primary rating of the earth path current transformer may not be related to the stator winding rated current as discussed in Section 5 3 2 Therefore the requirements for the earth path current transformer will be similar to that detailed in Section 5 3 2 as follows V gt 6N1 R 2R R W here V Minimum current transformer kneepoint voltage for through fault sta bility Maximum earth fault current N Earth path current transformer rated primary current Relay rated current R Resistance of current transformer secondary winding Q R Resistance of a single lead from relay to current transformer Q R Resistance of any other protective relays sharing the current transformer Q Note N should not be greater than 2 since 21 is the maximum measurable second ary current The earth path current transformer ratio should be selected accord ingly Reverse and low forward power protection functions For both reverse and low forward power protection function settings greater than Service M anual R5942B LG PG111 Chapter 3 Page 74 of 75 3 P_ the phase angle errors of suitable protection class current transformers will not result in any risk of maloperation or failure to operate However for settings less than 3 P_ itis recommended that the current input is driven by a correctly l
173. as the higher slope provides stability for through fault conditions especially if the generators CT s saturate Enable the 87G Generator Differential protection function only If necessary change the scheme logic input matrix so that only the 87G will cause the output relays to operate see Section 6 1 Sensitivity operating time and output relay tests Inject current into the l 4p input terminals A23 A24 Slowly increase the current until the relay operates Record the minimum operating current Accept and reset all alarms on the relay The Trip level Is1 with a 5 tolerance Inject 4xls1 Amps into the operating time input terminals A23 A24 and record the relay a diff O perating time lt 33ms Check the operation of the output relays against the scheme logic settings Check that the red Trip LED turns on and the yellow Alarm LED flashes when relay operates if selected to do so by the scheme logic matrix Check ALARM Protection 87G Gen Diff A appears on the display ignore the other alarms Reset all alarms Service M anual R5942C LG PG 111 7 1 2 7 1 3 Chapter 8 Page 22 of 66 Repeat the above tests for the terminals A27 A28 pair NPUt terminals A25 A26 and for the l gy input M easurement Checks Inject rated current through both the a input and the l ps input A17 A24 with A18 and A23 linked ignore relay tripping Record the current injected and the differ
174. ase of a power loss The fault recording is executed approximately every 5ms which is the same rate as the differential and bias currents are calculated by the differential protection The other measurements are calculated approximately every 20ms This may result in a misalignment between the two groups of measurements in the fault record The maximum misalignment is 20 ms Service M anual R5942B LG PG111 Chapter 4 9 4 9 5 9 6 Page 45 of 50 Record retrieval mechanism The event and fault records can be examined by using the following methods 1 Through the user interface via the View Records Section of the menu 2 Through the Print function in the Auxiliary Functions menu Section to produce a reporton a printer Event and fault records can also be automatically extracted by the remote access system They can then be displayed or stored in a file as they occur A record can only be automatically extracted once However they are retained in the non volatile memory until overwritten and can be examined on demand using the two methods listed above A Clear Event Record function is provided in the Auxiliary Functions Section of the menu to clear all the event and fault records from the relay s memory Alarm indication Alarms are events which require immediate attention from the operator These include failures detected by self monitoring relay tripping through the operation of the fault record trigger and operation o
175. asured O perating Time Operation of Output Relays Correct Operation Of Output relays Notes Service M anual R5942B LGPG111 Chapter 9 Page 22 of 52 67N Sensitive Directional Earth fault Polarizing Voltage Current Dual Measurements and Characteristic For Ve ene gt RCA Va Measurement of legua Expected Pick up Value M easured Pick up Value Measured Drop off Value Measurement of V gt Expected Pick up Value Measured Pick up Value Measured Drop off Value Measurement of RCA Expected Pick up Values Measured Pick up Value Measured Pick up Value Measured Drop off Value Measured Drop off Value lead lag lead lag Measurements and Characteristic For le l RCA V2 residual CE ep Measurement of residual Expected Pick up Value l Measured Pick up Value l Measured Drop off Value Measurement of V gt Expected Pick up Value Service M anual LGPG111 Expected Pick up Value Measured Pick up Value Measured Drop off Value Measurement of RCA Expected Pick up Value Measured Pick up Value lead Measured Pick up Value lag Measured Drop off Value lead Measured Drop off Value lag Operation of Output Relays Correct Operation Of Output relays N otes R5942B Chapter 9 Page 23 of 52 Service M anual R5942B LGPG111 Chapter 9 Page 24 of 52 51N Stator Earth Fault Measurement Checks In
176. asurement of V gt Inject 0 9 x V gt Volts into the V and V inputs terminals B25 B26 and terminals B27 Service M anual R5942C LG PG111 Chapter 8 7 13 3 7 14 Page 55 of 66 B28 Slowly increase the voltage until the relay picks up Record the smallest reading from either of the voltage inputs this is the pick up value W ith the relay operated slowly decrease the voltage injected until the relay resets Record the smallest reading from either of the voltage inputs this is the drop off value Pick up voltage V gt with a 5 tolerance Drop off voltage 0 95xV gt with a 5 tolerance Repeat the test to measure the pick up and drop off values of the high set element V gt gt Pick up voltage V gt gt with a 5 tolerance Drop off voltage 0 95xV gt gt with a 5 tolerance Measurement of time delay characteristic t gt W ith the same connections and conditions as above switch from a voltage below the setting to a voltage above the setting at the same time as starting a timer to obtain the operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check the ALARM Protection 590V gt appears on the display ignore other alarms Reset all alarms Record the operating time obtained O perating time t gt setting with a 5 tolerance 10 to 40mS Repeat the timing tests for the high set element V gt gt to measure the time delay t gt gt O perati
177. ating Current Rating 1A IEAS o o 3 3 Diff CT Ratio Differential CT Ratio 1 00 1 1 00 1 3 4 Sensitive Ia CT Sensitive Ia CT Ratio 1 00 1 Ratio 1 00 1 3 5 Residual CT Residual CT Ratio 1 00 1 Ratio 1 00 1 3 6 Earth CT Ratio Earth CT Ratio 1 00 1 1 00 1 3 7 Earth VT Ratio Earth VT Ratio 1 00 1 1 00 1 3 8 Phase CT Ratio Phase CT Ratio 1 00 1 1 00 1 3 9 Line VT Ratio Line VT Ratio 1 00 1 1 00 1 3 10 Comp VT Ratio Comparison VT Ratio 1 00 1 1 00 1 ee ee Table 14 The LGPG111 s Transformer Ratios Section of its menu The LG PG 111 can display all its settings and measurements in terms of the system quantities To do this the relay must know what the system CT amp VT ratios are and these are detailed in this section It should be noted that this feature only affects the displayed values the protection operates on the measured quantities from the secondary of the system CT s and VT s Transformer ratios are password protected and are settable in the range 1 00 1 through to 9999 1 in increments of the least significant digit 3 1 Display value Indicates whether the settings in the Transformer Ratios Section are being used to scale values for display A value of Secondary means the LGPG111 is not scaling display values W hereas a value of Primary means the transformer ratios are being used to scale values 3 2 Current rating Indicates the current rating of the LG PG 111 The current
178. ation Of Output Relays For 59N 2 Service M anual R5942B LGPG111 Chapter 9 Page 27 of 52 Correct Operation Of Output relays N otes Service M anual R5942B LGPG111 Chapter 9 Page 28 of 52 51V Voltage Dependent O vercurrent Measurement Checks Injected Voltage Measured Vab Measured Vbc Injected Current Measured la Measured Ib Measured Ic Characteristic and Operating Time for Restraint Fundion if applicable Rotation Vsl Vs2 K gt YTS treset SI or DT Measurement of I gt point 1 Phase Injected Expected Pick up Measured Pick up Measured Drop off Voltage a a ey ee C Phase Injected Expected Pick up Measured Pick up Measured Drop off Voltage a B JF T po S C Service M anual R5942B LGPG111 Chapter 9 Page 29 of 52 Measurement of O perating Time Characteristic Expected O perating Time M easured O perating Time Service M anual R5942B LGPG111 Chapter 9 Page 30 of 52 Characteristic and Operating Time for Controlled Function if applicable Rotation Vsl Vs2 K gt TMS treset SI or DT Measurement of gt Phase Injected Expected Pick up Measured Pick up Measured Drop off Voltage i a a Measurement of K gt Phase Injected Expected Pick up Measured Pick up Measured Drop off Voltage A SO ss Ee ee Measurement of O perating Time Characteristic Expected Operating Time
179. ator is not earthed there may still be a risk of maloperation of the instantaneous directional protection function with transient spill current generated by an external phase phase earth fault Such a fault could result in transient spill current with no dominating reverse zero sequence current and a significant residual polarising voltage which may exceed the maximum threshold setting of 10V for the directional protection In such a case the protection function would either need to be driven from a dedicated core balance CT with insulated cable glanding etc or tripping would need to be gated by operation of the spare firststage of the neutral voltage displacement protection function 59N 1 The time delay of this first stage of the neutral voltage protection function could be used as a method of providing transient spill current sta bility The operating current threshold of the directional earth fault protection function Iresidual gt should be set to give a primary operating current down to 5 of the minimum earth fault current contribution to a generator terminal fault W here itis not possible to achieve the required sensitivity with the minimum relay setting 0 005In and the required line CT ratio the use of a dedicated core balance CT of lower ratio will be necessary to operate the directional earth fault protection function The polarising voltage signal threshold setting Vep gt should be chosen to give a sensitivity equivalen
180. ators rated above 1 MVA itis usual to apply generator differential protection This form of unit protection allows discriminative detection of winding faults with no intentional time delay where a significant fault current arises The zone of protection defined by the location of the CT s should be arranged to overlap protection for other items of plant such as a busbar or a step up transformer Service M anual R5942B LG PG111 Chapter 3 Page 13 of 75 Where only a single VT is available the voltage balance protection function 60 should be connected to the VT via a main set of protection fuses and via a reference set The voltage polarising signal for the directional sensitive earth fault protection function 67N could be derived from a main VT broken delta secondary winding or via a set of interposing VT s as shown In either case the main VT must be 3 single phase or a 3 phase 5 limb transformer with the primary star point earthed To provide very sensitive earth fault protection with stability for external 2 phase to earth faults where the spill current from the 3 line CT s may cause false operation a dedicated core balance CT should be used for the directional sensitive earth fault protection function Under voltage 50 Over voltage Reverse power 60 Voltage balance Field failure 67N Sensitive directional earth fault Negative phase sequence 810 Over frequency Stator earth fault 81U
181. ble of conversion values from 0 to 45 is sufficient and a total of 256 points is used to provide a resolution of 0 18 The calculation needs to determine which of the eight 45 sectors the vector is positioned in to produce the actual phase angle In the LGPG111 the phase angle calculation is not used directly by any of the protection functions For those protection characteristics which are phase angle dependent they are realised directly from the Fourier components This avoids unnecessary processing of phase angles with the possible introduction of further errors The phase angles of V V and I are calculated and used by the frequency tracking algorithm Additionally the relative phase difference between and V is calculated and provided as a measurement a sensitive Frequency tracking The LG PG111 is designed to work over a wide frequency range from 5Hz to 70Hz To achieve this it is necessary to lock the sampling rate at12 samples per cycle with the power system frequency This ensures the frequency response of the Fourier filter and hence the relay s performance is constant over the specified frequency range The frequency tracking also provides frequency measurement for the protection functions If the sampling frequency f is exactly 12 times the power system frequency fy the vector of the tracking signal derived using Fourier techniques should rotate on the complex plane with an angular velocity of 2
182. ble with resistive termination of the extreme ends Connection method K Bus is a multi drop standard This means that a K Bus connection shown in Figure 1 can be made point to point or can be daisy chained together with a number of other products A chain of connected units is known as a spur and no branches may be made from the spur Recommended cable Itis standard convention to use the binary thousand of 1024 2 to define kilo in the context of memory capacity Thus the LGPG111 has 208x1024 212992 bytes of memory Service M LG PG111 5 4 1 3 5 4 1 4 5 4 1 5 anual R5942B Chapter 5 Page 12 of 23 J Z hk DA NIN IN KY aa ANANA Figure 1 K Bus connection arrangement on the LG PG 111 Twisted pair with outer screen to DEF STAN DARD 16 2 2c 16 strand 0 2mm diameter 40mQ per meter per core 171pF per metre core to core 288pF per metre core to screen Cable termination A three terminal 4mm screw block is provided on the LGPG111 Two terminals are for the twisted pair communications wires and the third is for the screen The screen connection is not internally connected to the LGPG111 in any way since the screen should be earthed at one point of the cable only normally at the mas
183. bled Enabled Disabled Enabled Disabled Enabled Disabled 60 Voltage Balance Vs gt Enabled Disabled Enabled Disabled Negative Phase Sequence Service M anual R5942B LGPG111 Chapter 9 Page 49 of 52 46 Neg Phase Seq Enabled Disabled Enabled Disabled 46 gt gt Thermal trip 12 gt gt K tM AX tM IN Kreset 46 gt NPS Alarm 12 gt t gt Field Failure 40 Field Failure Enabled Disabled Enabled Disabled Xa Xb t tDO Service M anual LGPG111 Scheme Logic R5942B Chapter 9 Page 50 of 52 In the following tables fillin the squares to represent 1 s to record the Scheme Logic settings in the LGPG111 Group 1 Settings INPUT MATRIX mi it a RHH TEETH n HF joa a MENEE SAAN BHAARBSER AS TEFEN 9839822 ng ggagddod L10 L11 eae iti EEE Easel tise REEE EEHEEHE EEE EREE EEEE REEE REEE Latch outputs L12 L13 L14 L15 L16 L17 L18 L19 L20 L21 L22 L23 L24 L25 L26 L27 L28 L29 L30 L31 Fault record trigger Alarm trigger OUTPUT MATRIX ANT PEP DREQR RORERDE SHEESH EEHEEHE EEHEEHE HEEPEEEH HEHEHHE EEHEEHE TPES HEERE Onna NANN Onnan Service M anual R5942B LGPG111 Chapter 9 Page 51 of 52 Group 2 Settings INPUT MATRIX OUTPUT MATRIX 3 i mi aT gE NAR Hi fe eefg8 biji TET
184. bled when running a generator away from the nominal frequency for example in the case of a variable frequency supply being used to drive a synchronous machine as a motor or to starta gas turbine prime mover The LPG111 continuously tracks the power system frequency and derives the negative phase sequence operating quantity algorithmically hth tal l where a 1 0 120 Depending on the type of generation scheme load unbalance can arise as a result of single phase loading non linear loads involving power electronics or arc furnaces etc uncleared or repetitive asymmetric faults asymmetric fuse operation single pole tripping and reclosing on transmission systems broken overhead line conductors and asymmetric failures of switching devices Lack of load current symmetry can be described in terms of a balanced negative phase sequence reverse phase rotation component of current existing with the balanced positive phase sequence component Any negative phase sequence component of stator current will set up a reverse rotating component of stator flux that passes the rotor at twice synchronous speed Such a flux component will induce double frequency eddy currents which cause heating of the rotor body main rotor windings damper windings and various other metallic rotor components Synchronous machines will be able to withstand a certain level of negative phase sequence stator current continuously where the rate of eddy current heating and t
185. c B27 B28 V on B21 B22 Viesi B23 B24 Check of pick up value Enable the 59 over voltage protection function only if necessary change the scheme logic so that only the 59 function will cause the output relays to operate Set the V gt setting to equal rated volts and the time delay setting t gt to 2 0 seconds N ote the protection function will operate only when the voltage at the V and V inputs are both above the setting V gt Inject 0 9 x V gt Volts into the V and V inputs terminals B25 B26 and terminals B27 B28 Slowly increase the voltage until the relay picks up Record the smallest reading from either of the voltage inputs this is the pick up value W ith the relay operated slowly decrease the voltage injected until the relay resets Record the smallest reading from either of the voltage inputs this is the drop off value Pick up voltage V gt with a 5 tolerance Drop off voltage 0 95xV gt with a 5 tolerance Measurement of time delay characteristic W ith the same connections and conditions as above switch from a voltage below the setting to a voltage above the setting at the same time as starting a timer to obtain the operating time Record the operating time obtained O perating time 2 0 seconds with a 5 tolerance 10 to 40mS M easurement of frequency Inject rated voltage with rated frequency into the V input terminals B27 B28 Record and check the frequency injected and the value measured b
186. can mode is available whenever the display is showing the alarm prompt message ALARM and the alarm LED is on either flashing or steady In this situation the RESET and ACCEPT READ keys can be used to scan through the alarm messages which can then be accepted or reset Since these two keys are accessible Service M anual R5942B LG PG111 Chapter 6 4 3 2 Page 11 of 91 with the front cover fitted they provide a convenient means for an operator to read these messages The ACCEPT READ key enters this mode and allows the alarm messages to be stepped through each press of the key selecting the next message After the last alarm message has been displayed the user will be prompted to press RESET to clear alarms The RESET key can then be pressed to clear the messages Alternatively the ACCEPT READ key can be pressed to accept the alarms without clearing them In this case if none of the alarms are still active the display returns to showing a non flashing ALARM message combined with a continuously illuminated alarm LED However for both cases if there are alarms which are still active an ALARMS still active message is displayed to indicate this condition and the ACCEPT READ key must be pressed to return to the default display The alarm message and alarm LED will remain on but not flashing although if the clear alarms action had been selected then only the active alarms will remain An ex
187. ce M anual R5942B LG PG111 Chapter 3 5 6 Page 75 of 75 Converting an EEC 185 current transformer standard protection classi fication to a kneepoint voltage The suitability of an IEC standard protection class current transformer can be checked against the kneepoint voltage requirements specified previously in Section 5 If for example the available current transformers have a 15VA 5P 10 designation then an estimated kneepoint voltage can be obtained as follows VA x ALF n ALF x la x Rot lt x a gt D tp oO Required kneepoint voltage Current transformer rated burden VA Accuracy limit factor C R m a7 urrent transformer secondary rated A esistance of current transformer secondary winding Q DT ro lt o If Ris not available then the second term in the above equation can be ignored Example 400 5A 15VA 5P 10 R 0 2 15 x 10 Vex 10x5x0 2 5 40V CHAPTER 4 Functional Description Service M anual LG PG111 Issue Control R5942B Chapter 4 Page 2 of 50 engineering document number 50005 1701 104 Issue Date Author Changes AP February 1995 Tony Yip amp Peggy Ling Original BP June 1995 Dave Banham M inor Corrections N PS protection description updated to reflect change in LG PG 111 functionality for software reference number 18LG PG 002XXXE Issue A onwards The N PS reset characteristic was an exponential
188. condary winding of a distribution earthing transformer or from a broken delta VT A sensitive setting can be applied A short time delay can be applied to stabilise the protection during voltage fluctuations due to VT failures or earth linkage during HV system faults The neutral voltage displacement protection function consists of a single measuring element with two independently adjustable time delays This protection function can be used to provide earth fault protection irrespective of whether the generator is earthed or not and irrespective of the form of earthing and earth fault current level It would be the main means of providing stator earth fault protection for indirectly connected machines when the current operated protection function 51N is used to provide stator winding inter turn protection as described in Section 2 3 2 A dedicated neutral voltage signal input is provided for this protection function This input also provides a polarising voltage signal for the sensitive directional earth fault protection function 67N Application to a directly connected generator For this mode of application illustrated in Figure 3 the neutral voltage displacement protection function should be driven from a broken delta connected secondary winding of a generator terminal VT that has its primary winding star point earthed This VT should be made up of three single phase units or should be a single phase unit with a 54imb core If the VT
189. cord the output relays operated Characteristic checks for 51N gt gt Enable the 51N gt gt High Set The 51N status should be left as Enabled since disabling it will disable both the low set and high set elements If necessary change the scheme logic input matrix so that only the 51N gt gt will cause the output relays to operate Record the stator earth fault protection settings le gt gt and t gt gt Measurement of le gt gt Inject 0 8 x le gt gt Amps into the input terminals A5 A6 and increase the current to check the 51N gt gt pick up value Decrease current to check the drop off value The Protection O peration Summary Section of the relay s menu can be used to determine these points without the need to wait for timer operation Accept and reset all alarms on the relay pick up value le gt gt setting with a 5 tolerance drop off value 95 of le gt gt setting with a 5 tolerance Measurement of time delay characteristic Service M anual R5942C LG PG 111 7 6 5 7 7 7 1 1 1 1 2 Chapter 8 Page 34 of 66 Inject 2 x le gt gt Amps into the input terminals A5 A6 to obtain the operating time Check ALARM Protection 51N gt gt SEF appears on the display ignore other alarms Reset all alarms on relay Compare the measured operating time with the setting allowing 5 10 to 40mS tolerance O peration of output relays for 51N gt gt Repea
190. cted Energized Displayed Relay output tests ContactName Or Relay Test Pattern Results As Expected N umber Entered Service M anual LGPG111 Relay inoperative alarm Alarm tested Scheme logic tests Scheme logic setting group tested R5942B Chapter 9 Page 13 of 52 C Service M anual R5942B LGPG111 Chapter 9 Page 14 of 52 Bit pattern entered in Set Events for Results displayed in Scheme O P cell Scheme Test cell Service M anual R5942B LGPG111 Chapter 9 Page 15 of 52 INPUT MATRIX OUTPUT MATRIX 7 i i T ni TAREE HEEL ELL BARE aQGR3HHE csgscens eeooSid SSeeeee8 RekEeRE TEER EHE HEH EE E RHEE PEREA E E EEE E E E Latch outputs JII TCT Fault record trigger TITT OIITIT Alarm trigger I TITT CTT L12 L13 L14 L15 L16 L17 L18 L19 L20 L21 L22 L23 L24 L25 L26 L27 L28 L29 L30 L31 Service M anual LGPG111 Commissioning Test Record For The LGPG111 R5942B Chapter 9 Page 16 of 52 TESTED AS DISCRETE RELAYS Date Tested by Company Site Generator Circuit M odel number Serial number Vx 1 Vx 2 In Commissioning Preliminaries Relay model number rating and module reference correct CT shorting switches in case checked Earth connection to case checked Insulation checked External wiring checked to draw
191. cur during operation at less than rated voltage The pick up level should be set to less than the voltage seen for a three phase fault at the remote end of any connected feeder see Section 2 6 The time delay should be set to allow the appropriate feeder protection to operate first to clear the fault and also to prevent operation of the protection during transient voltage dips A dedicated input is provided to block the operation of the under voltage and under frequency protection during run up or run down of the generator This input can be driven from an auxiliary contact in the circuit breaker This protection function responds to the phase phase voltage signals supplied to the relay via the main input VT s The protection function includes an adjustable time delay t which is initiated when all three under voltage elements detect a voltage below their common threshold setting V lt Under voltage protection is nota commonly specified requirement for generator protection schemes However under voltage elements are sometimes used as interlocking elements for other types of protection such as field failure In the case of LG PG111 such interlocking can be arranged by appropriate configuration of the relay scheme logic as already indicated in Section 2 9 W here only interlocking is required time delayed under voltage tripping would not be enabled The LGPG111 s under voltage protection function elements can also be used to e
192. current should result in operation of the generator differential protection function but use of the second stator earth fault protection element le gt gt as an instantaneous high set element offers a second method of quickly clearing this fault condition which may be seen as a prudent precaution Optional interlocked KERM earth fault protection LGPG111 Minimum earth fault level le Vph n Re Figure 9 system diagram Stator earth fault protection function co ordination example Service M LG PG111 anual R5942B Chapter 3 Page 22 of 75 Effective setting of neutral voltage displacement protection function 0 0451 0 0451f le Current Figure 10 Stator earth fault protection function co ordination example In such a situation the main current operated protection element le gt might be arranged to initiate a non urgent shutdown whereas operation of the additional protection element with a high setting and zero time delay le gt gt would be used to initiate an urgent shutdown In either mode of application the main stator earth fault current operated protection element le gt should be set to have a primary sensitivity of around 5 of the maximum earth fault current as limited by the earthing impedance Such a setting would provide protection for up to 95 of the generator stator windings The probability of an earth fault occurring in the lower 5 of the generator windings would be extremely low due t
193. d The first event message logged is real time clock set and is time stamped in the old time frame The second event message is real time clock valid and is time stamped in the new time frame at more or less the same instant These two time stamps allow the conversion of time stamps prior to the clock being set into the new time frame This is of course only possible for events as far back as the last relay reset power on which resulted in a real time clock invalid event record 3The magnitude and phase data may not be recorded at exactly 20ms intervals The interval can be as much as 0 02 1 foysx1 2 seconds For a 50Hz system this equates to a sampling interval any where between 20 amp 21 6ms This implies the total recording duration may be longer than indicated Service M anual R5942B LG PG111 Chapter 4 9 8 Page 47 of 50 The time base of the clock is derived from an internal free running crystal oscillator The accuracy of this crystal is approximately 50ppm which can result in an error of up to 3 seconds per day For precise synchronisation with an external clock source the LG PG 111 provides a logic input for a time synchronising signal This allows the relay s clock to be synchronised at regular intervals Test facilities Test facilities are provided to enable the LG PG 111 to be thoroughly tested during commissioning routine maintenance and fault finding operations The measurement functions al
194. d VT connections Particular care must be exercised when proving the polarity of the and or V polarizing CT and VT circuits as under normal operating conditions it is not possible to detect whether the polarizing inputis of the correct polarity If the polarizing input is incorrectly connected the system may mal rip or not trip for internal or external faults Service M anual R5942C LG PG 111 Chapter 8 Page 64 of 66 12 STABILITY CHECKS FOR 87G GENERATOR DIFFERENTIAL Carry out these tests as required It is recommended that CT and VT tests are carried out before these tests Ensure that the primary circuit is dead and isolated Connect a temporary short to the primary circuit as shown in Figure 4 Disable the Scheme Output cell in the Auxiliary Functions Section to prevent the relay tripping Run the generator up to normal speed with no excitation Slowly increase the excitation until the primary current is approximately full load Record all the current measurements on the relay and check that they are correct Check that the differential currents la Diff lb Diff and Ic Diff measured by the relay are less than 10 of the mean bias current measured by the relay Temporary Generator Short Circuit N ote O nly one phase connection is shown for clarity Figure 4 Arrangement for checking the stability of the 87G Generator Differential Service M anual R5942
195. d drop off values The Protection O peration Summary Section of the relay s menu can be used to determine this without the need to wait for timer operation Accept and reset all alarms pick up value K I gt setting with a 5 tolerance drop off value 0 95xK gt setting with a 5 tolerance Repeat the tests for phases B and C Measurement of time delay characteristic W ith the voltage conditions as above inject 2xK I gt Amps to obtain the operating time Record the operating time For the DT characteristic O perating time t seconds with a 5 tolerance 10mS to 40mS where tis the applied setting Service M anual R5942C LG PG 111 7 8 4 Chapter 8 Page 42 of 66 For the SI characteristic O perating time 10xTMS seconds with a 5 tolerance 10mS to 40mS where TMS is the applied setting Repeat the tests for phases B and C Characteristic and operating time for simple function Record the overcurrent settings I gt t TMS tRESET and the Definite Time DT or Standard Inverse SI characteristic applied The following tests should be applied to each phase element complete the tests for each element in turn Begin by testing phase A The following connections will be required during these tests Signal designator LGPG111 Connections Ls Al1A12 Ib A13A14 ig A15A16 Measurement of I gt Inject 0 8 x I gt Amps and slowly increase to measure the pick up value Decrease the
196. d to display one line of up to 50 characters Thus for the front panel abbreviated text is used where necessary to cope with the line break and reduced line length The format of cells on the remote system however takes full advantage of the increased line length to avoid the use of abbreviations etc The functionality of both interfaces is the same except that the remote interface can extract disturbance and event records for further analysis Both the front panel and remote access user interfaces are always available Although both share the same database they operate independently from one another However only one interface is allowed to carry outa setting change ata time Settings that are critical or relate to the operational scheme of the relay are password protected W hile an interface is in the setting change mode or the password protection has been removed a timer is started to detect any period of continuous inactivity at the interface W hen the period of inactivity has expired these modes are cancelled Also for the front panel the display will revert to its default display Each user interface access system has its own inactivity timer MULTIPLE SETTING GROUPS The LG PG111 provides two complete groups of protection and scheme logic settings either of which the protection can be switched to use There is also the option to disable this facility thus leaving the LGPG111 with just one setting group W ith the alternati
197. default display of the relay s menu system This will either be DATE AND TIME NOT SET UP oranalarm message 2 POWER ON FAILURES Failure of the relay to power up usually indicates a power supply microprocessor or front panel module problem A broken ribbon cable bus may also result in a seemingly dead relay 2 1 Power supply checks 1 Begin by checking all external DC auxiliary supply connections Check the DC supply on the relay terminals is within the power supply specification Check the polarity of the supply is correct 2 Check the normally open power supply alarm contacts terminals H3 amp H4 are closed If they are open remove the DC supply disconnect the power supply module from the ribbon cable bus and re apply the DC supply Check the nor mally open contact again If itis still open the module will have to be replaced 3 Ifthe normally open contact is closed with the module connected to the ribbon cable bus but the relay refuses to power up normally there is a fault in either the front panel or microprocessor modules 4 Ifthe normally open contact is open with the ribbon cable bus connected and the relay powered there is a short circuit fault which could be in any of the Service M anual R5942C LG PG111 2 2 2 3 Chapter 7 Page 7 of 14 remaining modules In turn disconnect the DC supply remove a module and re apply the supply until the contact closes the last module removed
198. dware calibration techniques using trimpots for example this software calibration procedure simplifies the production process and produces more reliable and accurate results Errors caused by the sampling delay which cannot be calibrated easily using hardware methods can now be compensated The third type of error is compensated for by having a look up table of magnitude correction factors versus frequency For a given frequency the relay will select the appropriate correction factor to compensate for the frequency response of the analogue input circuitry This table is determined at the design stage The compensation vector F can be expressed in complex form as F K cos 8o isin 80 W here K is the magnitude calibration factor and So is the phase calibration angle The look up table of magnitude correction factors versus frequency is represented by the function M f An analogue input is calibrated by multiplying by and M f to produce the calibrated output I I IxFxM f Service M anual R5942B LG PG111 Chapter 4 3 3 1 3 1 1 3 1 2 Ce Page 17 of 50 PROTECTION FUNCTIONS Generator differential 87G General description The generator differential function is a low impedance biased scheme with a dual slope bias characteristic The lower slope provides sensitivity for internal faults whereas the higher slope provides stability under through fault conditions during which there may be transient d
199. e 87G Current differential 51N Stator earth fault and 46 N egative phase sequence M easurement checks Inject 0 1 x rated current into the following current inputs Record and compare the Current injected with the value measured by the relay Allowing a tolerance of 5 Input Terminals l A7 A8 l residual a sensitive e Service M anual R5942C LG PG111 Chapter 8 6 1 2 6 1 3 Page 17 of 66 Inject 1 0 x rated current into the following current inputs Record and compare the current injected with the value measured by the relay Allowing a tolerance of 5 Terminals A23A24 A25A26 Input l A27 A28 l a diff b diff cdiff kge A17A18 fica A19 A20 l A21A22 AllA12 A13A14 A15A16 a Check of pick up value If necessary change the scheme logic so that only the 51V voltage dependent overcurrent is enabled Set this function to be used in the Simple mode and set the l gt setting value to equal rated current Inject 0 9 x rated current into the I input terminals A11 A12 and slowly increase the current until the relay picks up As there is a time delay associated with this function the Protection O peration Summary Section of the relay s menu can be used to determine the point at which this function starts to operate The Protection O peration Summary should indicate 0 when the current injected
200. e Access firs 6 20 Ia Diff Ia Diff 998mA 998mA Ih lt 3 Ib Diff Ib Diff 989mA 6 21 989mA per 6 22 Ic Diff Ic Diff 946mA 946mA ae 6 23 Ta Mean Bias Ia Mean Bias 1 462 A 1 462 A i 6 24 Ib Mean Bias Ib Mean Bias 493mA 493mA he 6 25 Ic Mean Bias Ic Mean Bias 1 500 A 1 500 A ae 6 26 T2 T2 163mA 163mA bos 6 27 I Residual I Residual 980 1mA 980 1mA 6 28 Te Te 982 0mA 982 0mA Ihe 6 29 Vab Vab 109 6 V 109 6 V fin te 6 30 Vbc Vbec 110 1 V 110 1 V o 3 31 Vea Vea 108 9 V 108 9 V 6 32 ine ae Ve L23 N 6 33 Active Power Active Power Aph 54 10 W Aph 54 10 W Reactive Power Reactive Power Aph 32 04 VAr 6 34 Aph 32 04 VAr 6 33 Phase Angle Phase Angle Aph 149 9 deg Aph 149 9 deg Frequency Frequency 50 00 Hz a 50 00 H Z Fault Report Fault Report Erased baa Ea Erased Table 17 The LGPG111 s View Records Section of its menu Service M anual R5942B LG PG111 Chapter 6 Page 44 of 91 The View Records Section allows event records to be examined The Event system categorises events into eight types 1 Exceptions 2 Relay output changes 3 Logic input changes 4 Protection operations 5 Non volatile EEPROM memory errors 6 Diagnostic errors 7 General events 8 Fault records 6 1 View last reco
201. e communications processor Logic input status A 14 bit binary flag representation of the optically isolated logic inputs to the relay W hen an input is energised its flag bit will show as a 1 otherwise it will show as a 0 This cell is duplicated in the Auxiliary Functions Section The bits are summarised in Table 7 Bit Name 0 27 810 Inhibit 1 51V Inhibit 2 51N Inhibit 3 Group Select 1 4 Group Select 2 5 Clock Sync 6 Input 6 7 Input 7 8 Input 8 9 Input 9 10 Input 10 11 Input 11 12 Input 12 13 Input 13 N ote Bits 6 to 13 are scheme definable and their names can be changed in the Input O utput Labels Section 1 13 Relay output status A 16 bit binary flag representation of the relay output status The LGPG111 has 16 output relays An energised relay is shown by a 1 and de energised by a 0 This cell is duplicated in the Auxiliary Functions Section The bits are summarised in Table 8 Service M anual LG PG111 Table 8 Bit flag assignment read right to left of the relay outputs N ote Bit Name F Relay Inoperative 1 Relay 1 2 Relay 2 3 Relay 3 4 Relay 4 15 Relay 5 6 Relay 6 7 Relay 7 8 Relay 8 9 Relay 9 10 Relay 10 11 Relay 11 112 Relay 12 13 Relay 13 14 Relay 14 15 Re
202. e internal scheme logic of the LGPG Reverse power protection function 32R The reverse power protection function offered by LG PG 111 is driven from an A phase sensitive current input CT and the A B voltage signal and measures true W atts In the event of prime mover failure a generator that is connected in parallel with a power system or other generators will begin to motor and active power will be drawn from the power system to cover alternator and failed prime mover mechanical losses To automatically detect this mechanical mode of failure in order to disconnect the afflicted machine from the power system reverse power protection is often applied The consequences of generator motoring and the level of power drawn from the power system will be dependent on the type of prime mover W here rapid prime mover damage could occur and or where a high level of power is drawn from the power system automatic generator disconnection should occur Typical levels of motoring power and possible motoring damage that could occur for various types of generating plant are given in table 1 Service M LG PG111 anual R5942B Chapter 3 Page 36 of 75 Prime M over Motoring Power Possible Damage Percentage rating Diesel Engine 5 25 Risk of fire or explosion from unburnt fuel Motoring level depends on compression ratio and cylinder bore stiffness Rapid disconnection is required to limit power loss and risk of damage Gas Turbine 10
203. e operation during transient over voltages Instantaneous protection with a setting of 130 150 of the nominal voltage can be implemented This protection function responds to the phase phase voltage signals supplied to the relay via the main input VT s The protection function includes an adjustable time delay t gt which is initiated when all three over voltage elements detect a voltage above their common threshold setting V gt A high set over voltage protection element V gt gt is also provided which can be set for instantaneous or time delayed operation using t gt gt An unsynchronised generator terminal over voltage condition could arise when the generator is running but not connected to a power system or where a single generator is running and providing power to an isolated power system Such an over voltage could arise in the event of a fault with automatic voltage regulating equipment or if the voltage regulator is set for manual control and an operator error is made O ver voltage protection should be set to prevent possible damage to generator insulation prolonged over fluxing of the generating plant or damage to isolated power system loads W hen a generator is synchronised to a power system with other sources a synchronised over voltage could only arise if the generator was lightly loaded and was required to supply a high level of power system capacitive charging current An over voltage condition might also be
204. e selected between 0 and 15 The bits are summarised in Table 37 page 62 Itis not possible to trigger the recorder when an output is reset 19 7 Number of records stored An indication of how many records are stored Can be 0 1 or 2 Note that for two records stored the recorder is stopped 19 8 Clear all records Allows currently stored records to be erased without the need to extract them _ Front Panel Remote Access Clear All Clear All Records No Records Press SET To Clear All Records Yes Clear All Record Table 45 States of the Clear All Records cell This cell is password protected and not included in the setting transfer R5942B Chapter 6 Page 70 of 91 Service M anual LG PG111 7 21 Test functions Front Panel Remote Access 20 0 TEST FUNCTIONS Test Functions 20 1 Lamp Test Lamp Test Off 20 2 Relay Test Relay Test 0000000000000000 0000000000000000 20 3 Scheme Logic Test 20 4 Group 1 o o 20 5 1 SchemeSetting Scheme Setting OK OK o o 20 6 1 Set Events In For Scheme 00000000000000000000000000000000 Test 20 7 1 Scheme O P Out 000000000000000 000000000000000 jer od 20 8 Group 2 o 20 9 2 SchemeSetting Scheme Setting OK OK o lt e 20 1 2 Set Events In 0 For Scheme 00000000000000000000000000000000 Test i 20 1 2 Scheme O P Out 00000000000
205. e setting group setting is disabled The menu setting disables logic input control of the active setting group and allows it to be controlled by the active setting group cell Additionally a remote access command for changing the active group is also enabled This cell is password protected Service M anual LG PG111 2 11 R5942B Chapter 6 Page 35 of 91 Active setting group Indicates the active setting group The cell is only visible if the second setting group has been enabled The current group selection can also be changed if the group selection cell indicates menu Valid settings are 1 and 2 The setting is password protected An event record is generated for a change in the active setting group The cell is duplicated in the System Data Section as an indication only cell Remote getting Allows remote access setting capability to be disabled Can be either Disabled or Enabled W hen disabled settings can only be changed through the front panel This setting is password protected and is duplicated in the Remote Communications Section Inactivity timer Specifies the duration of inactivity on a user interface before the interface resets The time may be specified between 5 and 30 minutes in 5 minute increments Stator EF timer inhibit Defines the operation of the stator EF timer inhibit optically isolated logic input The cell can be Disabled High Set Low Set or Both The
206. e settings have been supplied as a setting file on a diskette Some of the relay s settings are password protected To remove or unlock these cells the relay s password must be entered into the password cell in the System Data Section The relay s default password is AAAA Password protection can be restored by resetting this cell for the front panel interface this means pressing the RESET key when the password cell is displayed The LGPG111 implements separate password locks for each user interface entering the password in one interface will not unlock the other one If the password has been lost or forgotten an emergency password can be provided by ALSTOM Each user interface has an inactivity timer The duration of the timer can be set between 5 and 30 minutes in the Auxiliary Functions Section W hen the timer expires cells which have not had a setting change confirmed will return to their previous value and the password lock will be enforced The front panel will also return to displaying its default display Enter the relay settings from the setting schedule and check If you have a parallel printer and suitable data connection lead the settings can be printed for comparison and asa permanent record See chapter 6 for more details about the parallel printer After entering the scheme logic check the Scheme Setting cell in the Test Functions Section indicates OK Check the model and serial numbers displayed in the Sys
207. e system overcurrent protection failing to respond In this case it would be expected that the generator backup overcurrent should operate O peration of generator overcurrent protection in the above circumstances can be assisted by employing voltage dependent protection as discussed in Section 2 6 W here there is a parallel set of generators and where the fault is relatively remote from the generators even the generator voltage dependent protection may fail to respond to the fault If the fault is asymmetric and if the negative phase sequence thermal protection function has been set and enabled the unbalanced fault current may be sufficient to operate this form of generator protection The worst situation would be for an uncleared three phase fault Although such a fault would be rare it may be that the only form of protection that would reliably detect the fault would be generator under voltage protection Even in the case of generators feeding an interconnected power system through a transmission or distribution connection means of clearing a fault at the remote end of the longest feeder from the generator bus should be provided in the event of feeder protection failing to clear the remote fault W here duplicated feeder protection and breaker fail protection is provided as with most primary transmission circuits the probability of having to rely on generator backup protection to clear such a fault would be extremely low In the case of an
208. eak radial transmission link to the load centre stability of generation may be an issue N ormally steps would be taken to minimise the risk of instability by keeping the transmission impedance to a minimum and by employing high speed transmission protection with auto reclosing but the risk of pole slipping and the need for pole slipping protection may still exist Pole slipping protection is frequently requested for relatively small generators running in parallel with strong public supplies This might be where a co generator runs in parallel with the distribution system of a public utility which may be a relatively strong source but where high speed protection for distribution system faults is not provided The delayed clearance of system faults may pose a stability threat for the co generation plant W ith LGPG111 there is no specific pole slipping protection function but some of the protection functions provided will offer a method of ensuring delayed tripping if appropriately applied Voltage dependent overcurrent protection function 51V In a similar manner to the reverse power protection function the voltage dependent overcurrent protection function would operate cyclically with the periodic high levels of stator current that would arise during pole slipping These peaks of current may also be accompanied by coincident drops in generator terminal voltage if the generator is near the electrical centre of swinging As discussed in Sec
209. ection can also be arranged to initiate local load shedding where appropriate Under frequency operation of a generator will occur when the power system load exceeds the prime mover capability of an isolated generator or of a group of generators W here the system load exceeds the alternator rating but not the prime mover rating the alternator could become overloaded without a frequency drop It would therefore be important for the alternator manufacturer to provide stator winding temperature measurement devices to give alarm or to automatically shut down the generator before winding thermal damage results Power system overloading can arise when a power system becomes split with load left connected to a set of islanded generators that is in excess of their capacity Such Service M anual R5942B LG PG111 Chapter 3 Page 55 of 75 events should be allowed for by system planners and automatic system load shedding should be implemented so that the load would rapidly be brought back within the generation capacity In this case under frequency operation would be a transient condition as during power swings The degree of load shedding would have to take into account the fact that some generating plant e g gas turbine plant may have a reduced power capability when running below nominal frequency In the event of under shedding of load the generators should be provided with backup under frequency protection to shut down the generating plant
210. ection must be time graded with other earth fault protection The setting employed should be less than 33 of the earth fault level A setting of 5 of the earth fault level should be applied for applications where the differential protection provides less than 95 coverage of the stator winding Applied to in directly connected generators with the generator earthed via a distribution transformer Can be supplied from a CT in either the primary or secondary circuit of the distribution transformer W ith a CT in the primary circuit the protection has the advantage of being able to detect an earth fault which causes flashover of the primary winding of the distribution transformer W ith the CT in the secondary circuit the protection has the advantage of detecting a short circuit across the loading resistor A sensitive 5 setting can be applied to the first tripping stage a short time delay can be applied to stabilise the protection against small earth currents due to VT failures or earth leakage during HV system faults The second tripping stage can be utilised as a high set A 10 setting and instantaneous operation ensures fast clearance of generator earth faults The current operated stator earth fault protection function consists of two independent elements The main element le gt can be set with an adjustable standard inverse time operating characteristic or a definite time delay The additional element le gt gt is provid
211. ed current into the input terminals A7 A8 Rotate the phase difference lagging to measure the phase angle when the relay picks up and drops off Rotate the phase difference leading to measure the pick up and drop off phase angles Record the phase angles measured Pick up phase angles RCA 90 with a 5 tolerance Drop off phase angles RCA 95 with a 5 tolerance O perating region RCA 90 to RCA 90 with a 5 tolerance Service M anual R5942C LG PG111 Chapter 8 6 4 7 1 Tlel Page 21 of 66 Final checks The instructions given in Section 8 Logic inputs Section 9 Contact tests and Section 10 Scheme logic tests should now be carried out Secondary injection for testing each function as a discrete unit N ote the tolerances quoted throughout this section are the acceptable limits of the relay s operation and as such do notinclude any allowance for instrumentation errors The commissioning engineer should make suitable adjustments to the tolerances based on the accuracy of the measuring test equipment used 87G Generator differential The generator differential function is used for the protection of the stator winding for single phase or poly phase faults Such conditions can produce high fault currents therefore fast fault clearance is required The function is a low impedance bias scheme and has a dual slope bias characteristic The lower slope provides sensitivity for internal faults where
212. ed for instantaneous protection or for adjustable definitetime operation This element has an independently adjustable current setting and may be used as a high set element in some applications A dedicated single phase current input is provided for this protection function The current applied to this input can also actas a polarising signal for the sensitive directional earth fault protection function 67N Service M anual R5942B LG PG 111 ae eas 2 3 2 Chapter 3 Page 20 of 75 The inversetime operating characteristic of the main protection elementis governed by the following formula 0 14 0 02 Gi Application to a directly connected generator t TMS x For this application illustrated in Figure 3 the time delayed main earth fault protection element le gt should be set with a current setting and time characteristic inverse or definite time to co ordinate with the fast sensitive directional earth fault protection 67N of any parallel generators It must also co ordinate with the time delayed earth fault protection of the outgoing feeders from the generator bus The current setting should also be less than 33 of the earth fault current contribution of the protected machine W here the generator differential protection function would not offer 95 coverage the stator windings for earth faults the setting le gt should be as close as possible to 5 of the machine contribution to a solid terminal earth fault Thi
213. ed in Section 2 10 since the under voltage protection element must not be inhibited in this application Here a logic input must be assigned to prevent the under voltage protection from operating output relays that will initiate plant tripping but the under voltage protection will still be available for the dead machine protection logic The under voltage protection will be free to operate a contact to act on the relay setting group selection logic inputs This is achieved by taking them both to logic 1 to select setting group 2 after the under voltage protection function responds to the shutdown and as long as no other protection function is operated The over voltage protection function threshold settings V gt and V gt gt should both be set to 99V in the group 2 setting schedule and the over voltage time delay t gt should be set to 1s The over voltage protection should not be arranged to initiate tripping or Select Group 2 RL13 gt Connect externally to Logic inputs 3 amp 4 ns rns R15 SCHEME LOGIC GROUP 1 SETTING Figure 21 Dead machine protection scheme logic for group 1 setting to give an alarm but should output contact to make the relay setting group selection logic inputs inputs 3 and 4 both logic 0 to select setting group 1 as illustrated in Figure 22 W hen the generator is run up again group 2 operation of the over voltage protection elements will result in group 1 settings being re estab
214. ed value of pick up for Xa Xb is given by the equation Xa Xb V Ixv3 where V and are the injected volts and current Calculate the required values of volts and current to inject W ith the phase angle meter reading 60 leading inject the calculated value of current and inject 1 1 x calculated voltage Reduce the voltage slowly until the relay operates Record the voltage and current injected for operation Measurement of Xa The expected value of Xa is given by the equation Xa V Ixv3 where V and are the injected volts and current Calculate the required values of volts and current to inject W ith the phase angle meter reading 60 leading inject the calculated value of current and inject 0 9 x calculated voltage Increase the voltage slowly until the relay operates Record the voltage and current injected for operation O perating Time Calculate the volts and current required to simulate a fault corresponding to a resistance of Xa Xb 2 Apply the injection to obtain the operating time The tolerances for the operating time is 5 10 to 60mS Check the red Trip LED turns on steadily and the yellow Alarm LED flashes when the relay operates Check the ALARM Protection 40 FF appears on the relay ignore other alarms Reset all alarms Service M anual R5942C LG PG111 Chapter 8 7 4 3 7 5 7 5 1 Page 29 of 66 O peration of output relays Repeat the previous injection test to opera
215. eder protection to clear remote end feeder faults The delay should preferably be longer than the time required for the generator back up overcurrent protection function to respond to such a fault Additionally the delay should be long enough to prevent unwanted operation of the under voltage protection function for transient voltage dips during clearance of faults further into the power system or by starting of local machines The required time delay would typically be in excess of 35 55 To prevent tripping of the under voltage protection function following normal shutdown of a generator a normally closed circuit breaker auxiliary contact should be used to energise the under voltage inhibit logic input W hen this inhibit input is energised under voltage protection function trip initiation and alarm initiation are blocked However the under voltage protection function elements will still be available for initiation of dead machine protection as discussed in Section 3 1 Over voltage protection function 59 Summary O perates when the three phase voltages are above the common set point Two tripping stages each with an adjustable timer Protects against damage to the generator insulation and that of any connected plant Recommended for hydrogenerators which may suffer from load rejection Time delayed protection should be set with a pick up voltage of 100 120 of the nominal voltage and a time delay sufficient to overcom
216. el s display when the relay locks out The lock out causes the relay to be continually reset by the operation of the watchdog The relay inoperative output relay will remain de energised See chapter 6 for a summary of front panel user interface messages Calibration Vector Raise alarm Set calibration data to default values Communications Raise alarm Attempt once to recover the failure by Hardware Fail watchdog reset Subsequent failures cause relay to disable the serial communications EEPROM W rite Fail Group Select Input Fail Raise alarm The current setting group remains unchanged LCD Fail Raise alarm Disable front panel user interface local access Watchdog inoperative W atchdog Timer too Raise alarm fast EEPRO M Errors for Raise alarm settings other than See chapter 6 fora description of non volatile EEPRO M scheme logic settings memory errors Table 5 Summary of minor errors detected by the self monitoring function Relay Fault Actions By Relay Uncalibrated Analogue Disable protection raise alarm de energise relay Module inoperative output Analogue Module Fail Raise alarm de energise relay inoperative output Attempt once to recover the failure by hardware reset Subsequent failures cause relay to disable protection EEPROM error in Disable protection raise alarm de energise relay scheme logic settings inoperative output Table 6 Summary of fatal errors detected by
217. electrical loading W hen a rise in running speed occurs the governor should quickly respond to reduce the mechanical input power so that normal running speed is quickly regained O ver frequency protection may be required as a backup protection function to cater for governor or throttle control failure following loss of load or during unsynchronised running The LG PG 111 protection function settings should be selected to co ordinate with normal transient over frequency excursions following full load rejection The generator manufacturer should declare the expected transient over frequency behaviour which should comply with international governor response standards A 10 over frequency should be continuously sustainable Voltage balance protection function 60 Summary O perates when a voltage difference above a selectable threshold is detected Detects VT fuse failure Supplied from the secondaries of two VTs or two separately fused secondary circuits of a single VT Used to raise an alarm and block voltage sensitive protection if necessary A voltage difference of 5v should be set unless the VTs are of dissimilar ratios or a voltage unbalance exists during normal operation This LG PG 111 function is provided as a method of identifying blown VT fuses so that an alarm can be raised and so that unwanted generator shut down by the voltage sensitive protection functions can be prevented The voltage balance protection f
218. ensitive 11 Start Line Current Ph A 12 End la 13 Start Line Current Ph B 14 End i 15 Start Line Current Ph C 16 End Ic 17 Start Bias Current Ph A 18 End la Bias 19 Start Bias Current Ph B 20 End Ib Bias 22 End Ic Bias 24 End la Diff 26 End lb Diff 27 Start Differential Current Ph C 28 End Ic Diff Table 13 Terminal allocation of the analogue and status input module block A Terminal Number Description 1 27 amp 81U Inhibit 2 3 51V Timer Inhibit 4 Ai 5 51N Timer Inhibit 6 7 8 9 Setting G roup Select 2 E e oer 11 Clock Sync ae E 19 Start Earth Path Voltage 20 End Ve 21 Start Comparison Voltage 22 End ee 23 Start Comparison Voltage 24 End re 25 Start Measurement Voltage 26 End K Table 14 Terminal allocation of the analogue and status input module block B Service M anual R5942B LG PG111 Chapter 5 Page 18 of 23 character alpha numeric liquid crystal display LCD and a 7key keypad W ith the glass cover in position only two of the seven keys are accessible Also included on the front panel are four indication LED s and two 25 pin D type sockets One of the sockets marked SERIAL is the front RS232 port for IEC870 serial communications The connection for this serial port see Table 15 is configured as a data communication equipment DCE No handshaking control signals are provided The other socket marked
219. ential and bias current measured by the relay allowing a 3 tolerance Accept and reset all alarms on the relay N ote Injected current lir hias 0 5xI Repeat the test for phase B A19 A26 with A20 and A25 linked Repeat the test for phase C A21 A28 with A22 and A27 linked mean bias Bias characteristic The 87G Generator Differential has three elements one for each phase The 87G uses the highest mean bias current measured out of the three phases as the bias for all three elements The detailed bias characteristic is described in Error AutoText entry not defined For the following tests always keep the current injected into the bias coil greater than the current injected into differential coil Record the differential protection s settings Is1 K1 Is2 and K2 Reference to these values is made in the following text For A N faults Diff coil terminals A23 A24 Bias coil terminals A19 A20 For BN faults Diff coil terminals A25 A26 Bias coil terminals A21 A22 For CN faults Diff coil terminals A27 A28 Bias coil terminals A17 A18 Lower slope The expected trip level l can be calculated from the following equation lie Trip level Isl K1 x with a 5 tolerance mean bias Inject 0 5 x Is2 Amps into the Bias coil and inject0 5 x Isl Amps into the Diff coil Slowly increase the current injected into the Diff coil until the relay operates The measured mean Bias and Differential currents are
220. ep to be introduced This prompts the user to confirm the setting alterations to the section as a whole by pressing the SET key Alternatively the RESET key can be pressed causing the alterations to be undone or aborted In setting mode the amp arrow keys may be used to select individual setting fields when more than one exists For example to select individual characters of a string setting or to select each field of the calendar clock cell The SET key confirms a setting and cancels setting mode In certain situations it is possible to enter a setting which the LGPG111 will reject for example an incorrect password or too many analogue channels in the disturbance recorder set up In this case the message Sorry Setting Is Invalid will appear and the arrow key must be pressed to return to setting mode The RESET key cancels setting mode without making any setting changes Additionally for a few cells there is a reset action associated when the cell is displayed normally as part of the browse For example resetting the password cell re enables the password protection If the arrow key is pressed on a cell which is nota setting the message Not A Setting is displayed If the cell is currently password protected the message Password Protected is displayed In both cases pressing the lt arrow key will Service M anual R5942B LG PG111 Chapter 6 Page 14 of 91 return t
221. er The remote access setting transfer does not include this cell Service M anual R5942B LG PG111 Chapter 6 Page 68 of 91 19 2 Data capture Determines the operating mode of the disturbance recorder Front Panel Remote Access Data Capture Data Capture Raw ADC Samples Raw ADC Samples Data Capture Data Capture Magnitudes amp Phases Mag amp Phase Table 43 States of the Data Capture cell The disturbance recorder can be setup to record either the raw data from the analogue to digital converter hardware or the data from the output of the signal processing software Raw data is captured at twelve samples per electrical cycle and is frequency locked Each of the two disturbance records can hold 768 such samples and hence provide a recording duration of 64 electrical cycles Raw data is not magnitude and phase calibrated Magnitude and phase data is captured approximately every 20ms from the outputs of the software signal processing The data is in the form of a magnitude and phase vector of the fundamental frequency component and is fully calibrated Each of the two disturbance records can hold 384 such samples which at 20ms intervals provides 7 68 seconds of data 19 3 Post Trigger cycles Determines how long recording will continue after a trigger For raw data the trigger position can set anywhere between 0 amp 64 posttrigger cycles For magnitude and phase data the trigger position can be set anywhere b
222. er forward reactive current is maintained e g 60 until AVR n Service M anual R5942B LG PG111 Chapter 3 Page 38 of 75 STABLE P gt OPERATE Figure 13 Reverse power protection function characteristic P gt Setting 03W 3w 0 5w 1 0W 1 0W 2 0W 4 0W 6 0W 80W OW Theoretical Angle 89 7 89 5 89 1 89 1 86 2 84 3 82 4 Boundary Table 2 O perating signi range of LGPG111 reverse power protection function action takes place The operating angle range of the reverse power protection may have to be in excess 89 The operative angle range of the LGPG111 reverse power protection function is given for various power threshold settings in Table 2 To achieve the accuracy of current angle measurement required for sensitive reverse power protection a dedicated high accuracy input CT is provided with the LGPG111 and the operative current range for the reverse power protection function is limited to rated current see Figure 14 W here the sensitive reverse power protection function is required less than 3 P_ this dedicated current input should be driven by a high accuracy measurement CT and the burden imposed on this CT should be in line with the CT classification To take into account inevitable phase errors that will exist between CT and VT signals on site the reverse power protection function characteristic can be finely rotated in 0 1 steps to compensate for site errors The method fo
223. erative Range 19 2 32 4V 24 40 8V 38 4 64 8V 88 150V 176 300 V Maximum W ithstand 36 5 V 45 9 V 72 9 V 168 8 V 3375V 337 5 V Table 1 Auxiliary Vx1 operating ranges Optically isolated logic input supply Vx2 Check the polarity of the optically isolated logic input supply wiring corresponds to the relay s connections Remove the auxiliary supply fuse and isolation link and check the polarity and measured value of the auxiliary supply The supply must be within the operating range specified for Vx 2 in the following table Replace the isolation and fuse links N ominal Vx2 24 27V 30 34V 48 54V 110 125V 220 250V 0 perative Range 19 2 32 4 V 24 40 8 v 38 4 64 8 V 88 150 v 176 300 v Maximum W ithstand 36 5 V 45 9 V 729V 1688V 337 5 V Table 3 Auxiliary Vx2 operating ranges Service M anual R5942C LG PG111 Chapter 8 4 3 4 4 4 5 5 1 Page 11 of 66 Energizing the LGPG111 Connect the auxiliary supply to the LGPG111 The relay should power up the display should read DATE AND TIME NOT SETUP and the green Relay Healthy LED should be illuminated If the relay has been energized before and a trip or alarm condition was present when the relay was de energized upon energization this trip or alarm indication will be given and it will be necessary to reset this indication O ther power on conditions should be checked off against the fault diagnosis Chapter especially if the relay
224. erator Differential Enabled Isl O 05 A Kl 0 oe Is2 1 20 A K2 150 Table 5 Generator differential settings when the alternative setting group facility is enabled 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 System data Contains basic information about the LGPG111 such as its model and serial numbers The password cell is also in this section Auxiliary functions Contains a number of cells providing status information about the relay and a number of miscellaneous cells controlling some configuration aspects The cell for printing various reports on the front panel s parallel portis also in this section Transformer ratios The LGPG111 provides the ability to display all its settings and measurements in terms of the system quantities To do this the relay must know what the system CT amp VT ratios are and these are detailed in this section It should be noted that this feature only affects the displayed values the protection operates on the measured quantities from the secondary of the system CT s amp VT s Measurements 1 Provides all the fundamental measurements which the LG PG111 has obtained or derived from its inputs Measurements 2 This section complements the Measurements 1 section by providing all the other measurements the LGPG111 is making View records Allows event records to be examined Protection function status Provides a quick summary of whic
225. ere is no requirement for a comparatively wide dynamic range therefore only one gain is selected The following sub sections discuss the design considerations for each group of inputs Generator differential CT inputs Six current inputs are assigned specifically for the differential function with two inputs per phase A special type of input transformer called a transactor is used internally to measure the current inputs Transactors provide the differential function with im proved stability when an offset waveform is applied For each phase one inputis used to measure the bias current the other input is used to measure the differential current as shown in Figure 2 The differential function requires two bias current measurements one from each end of the stator winding The LGPG111 directly measures one of these and calculates the other from the differential and bias inputs as explained in Section 3 1 This approach saves an extra input per phase which allows the LGPG111 to achieve its compact size The performance of the relay is not affected by whether the bias input is con nected to the line end CT or the neutral end CT The differential function provided by the LGPG111 is a low impedance biased scheme However if there is a specific requirement for a high impedance scheme then external stabilising resistors can be connected as explained in the Application N otes chapter 3 The current input range is up to 20 48xIn beyond w
226. esponse to HV system earth faults is undesirable since it should be the HV standby earth fault protection see Figure 5 which deals with an uncleared HV earth fault fed by the generator In the past such correction of voltage signals has been addressed by adopting phase neutral voltage measurement or the use of a star delta interposing VT Such an approach cannot be adopted with LGPG111 since the relay voltage inputs are common to other protection and measurement functions that would be undesirably affected by voltage signal correction The LG PG111voltage restrained current setting is related to measured voltage as follows Current Setting Is I gt for V gt Vs I gt K 1 gt K I E MN for Vs2 lt V lt Vs1 sl s2 K 1 gt for V lt Vs2 Where Current setting at voltage V V Voltage applied to relay element The protection operating time characteristic can be set as definite time or inversetime according to the following curve formula 0 14 USE Is The performance criteria on which the settings of the voltage restrained overcurrent protection function should be based are similar to those discussed for the voltage controlled mode in Section 2 6 1 The current setting at the normal level of voltage I gt should be set to give a primary operating current in excess of the maximum possible generator load current This should include a margin to allow for measurement t TMS x Service M anual R5942B LG PG111
227. est the relay is heated to 100 the trip value then the relay is allowed to cool fora known period of time then the fault is re applied until the relay operates By this method itis possible to show that the Kreset function is working correctly The equation to calculate the time taken to fall to a thermal value O assuming that the thermal value is at 100 initially where is the value indicated in the protection Op summary is as follows Kreset 0 Ig Jo ea Service M anual R5942C LG PG111 Chapter 8 Page 48 of 66 The equation to calculate the thermal value 6 to which the generator will cool after a time thas expired assuming that the thermal value is at 100 initially where 8 is the value indicated in the protection O p summary is as follows 12 hf Kreset d e x100 The equation to calculate the time taken to rise from an initial thermal value 6 to 100 is as follows Kreset I AN log d F 12 gt gt 2 For the following tests itis assumed that the generator is allowed to cool from 100 to 88 7 the point at which the 46 gt gt output will reset Inject 6 93 x 12 gt gt Amps into the and inputs so that phases A and B are in anti phase terminals A11 A13 with A12 and A14 linked The 12 measurement in the relay will indicate 4 x 12 gt gt for this condition Stop injection when the relay operates a thermal value of 100 At the same time
228. ettings The Lamp Test function turns the four LED s to their opposite states for a duration of two seconds The response of the relay healthy LED is slower than the rest due to the design of the mono stable circuit used to operate it The Relay Test function is a 16 bit binary flag setting with each bit representing a relay output contact Before the test is carried out the scheme output must be inhibited with the Scheme O utput setting Then by setting the binary bits from zero to one will cause the corresponding relay outputs to operate The relays are de energised if the bits are reset to zero W hen the Scheme O utput setting is restored to enabled all the bits will be forced to reset The Scheme Setting check looks for any half programmed logic word in the scheme logic settings It warns that for a particular logic line the input word has been programmed but not the output word or vice versa The warning is displayed in the Scheme Setting cell in the form Error Line X where X is the number of the erroneous logic line The Scheme Logic Test allows the user to check that the settings of the scheme logic Service M anual R5942B LG PG 111 9 9 9 10 9 10 1 9 10 2 Chapter 4 Page 48 of 50 are entered correctly The user can enter an input bit pattern to the scheme and check its logic output This test is run independently of the actual scheme itself and will not affect the relay s normal operation Print
229. etween 0 amp 384 posttrigger cycles 19 4 Analogue channels Specifies which analogue channels are to be recorded The disturbance recorder can record any eight of the seventeen analogue inputs and all the digital status information about the logic inputs and relay contact outputs This setting allows any combination up to eight of the seventeen analogue inputs to be selected for data capture by setting the appropriate bits to 1 If more than eight bits are set to 1 the setting will be rejected Service M anual R5942B LG PG111 Chapter 6 Page 69 of 91 Bit Name 0 VbcComp 1 VabComp 2 Vbc 3 Vab 4 la Sensitive 5 la 6 Ib 7 Ic 8 la Bias 9 la Diff 10 lb Bias 11 lb Diff 12 Ic Bias 13 Ic Diff 14 le 15 I Residual 16 Ve Table 44 Bit flag assignment read right to left of the Analogue Channel select cell 19 5 Logic input trigger Specifies which logic inputs can trigger the disturbance recorder A bit set to 1 allows that logic input to trigger the recorder when itis energised Any number of logic inputs can be selected between 0 and 14 The bits are summarised in Table 7 page 28 Itis not possible to trigger the recorder when an input is de energised 19 6 Relay output trigger Specifies which relay outputs can trigger the disturbance recorder A bit set to 1 allows that output to trigger the recorder when it is operated Any number of outputs can b
230. examples of the protection and scheme logic reports where generated with only one setting group enabled if both setting groups where enabled then settings for both groups would have been printed Each report begins with a header and ends with End of Report The header consists of the Description and Plant Reference entries from the System Data Section of the menu followed by the relay s serial number and the date and time System settings LGPG RELAY lt Not Defined gt Serial Number 0000000 Printed on Tue 1994 Aug 23 Lo 33 3 53 System Data Plant Reference lt Not Defined gt Model Number LGPG11101S533LEA Serial Number 0000000 System Frequency 50 Hz Auxiliary Functions Scheme Output Enabled Second Setting Group Disabled Inactivity Timer 30 min Stator EF Timer Inhibit Disabled Clock Synchronised Disabled Default Local Display Date amp Time Transformer Ratios Display Value Secondary Current Rating 1A Differential CT Ratio 1 00 1 Sensitive Ia CT Ratio 1 00 1 Residual CT Ratio 1 00 1 Earth CT Ratio 1 00 1 Earth VT Ratio 1 00 1 Phase CT Ratio 1 00 1 Line VT Ratio 1 00 1 Comparison VT Ratio 1 00 1 Service M anual R5942B Chapter 6 Page 76 of 91 Input Output Labels Digital Input Labels Input 6 Input 6 Input 7 Input 7 Input 8 Input 8 Input 9 Input 9 Input 10 Input 10 Input
231. f any one of the latched output contacts selected by the Latch O utputs setting Besides these initiations itis possible to select other scheme logic outputs to generate an alarm message An Alarm Record Trigger setting is provided which is the selection of the fifteen relay output contacts W hen an alarm occurs the alarm LED will flash to indicate that there is an outstanding alarm The word ALARM will also be flashing on the front panel s display provided that the front panel user interface is at the default level A user can then perform an alarm scan which scans through the alarm messages The alarm messages are summaries of alarms that have occurred At the end of the alarm scan the user is prompted to reset the alarms This also resets the LED s and the latched output contacts provided that the alarm conditions have already disappeared The alarm scan is not available remotely However an alarm flag is transmitted when an alarm occurs The remote access system is able to indicate the presence of an alarm Additionally a Relay Alarms cell is available in the Auxiliary Functions Section of the menu to provide another means of indicating the alarm status This cell can also be used to clear the alarms and LED s either locally or remotely and to reset the latched output contacts Disturbance recording A maximum of two disturbance records can be stored in volatile memory RAM A record will remain in the buffer area until iti
232. f output relays 26 Field failure 26 M easurement checks 26 Characteristic and operating time 28 O peration of output relays 29 67N Sensitive directional earth fault 29 M easurements and characteristic for polarizing voltage V 29 M easurements and characteristic for polarizing current 30 O peration of output relays 31 51N Stator earth fault 31 Measurement checks 32 Characteristic and operating time for 51N gt 32 O peration of output relays for 51N gt 33 Characteristic checks for 51N gt gt 33 O peration of output relays for 51N gt gt 34 59N Neutral Displacement 34 Measurement checks 34 Characteristic and operating time for 59N 1 34 O peration of output relays for 59N 1 35 O perating time for 59N 2 35 Service M anual R5942C LG PG111 Chapter 8 Page 5 of 66 7 7 5 Operation of output relays for 59N 2 35 7 8 51V Voltage dependent overcurrent 36 7 8 1 Measurement checks 36 7 8 2 Characteristic and operating time for restraint function 37 7 8 3 Characteristic and operating time for controlled function 40 7 8 4 Characteristic and operating time for simple function 42 7 8 5 Fault record checks 43 7 8 6 Operation of output relays 43 7 9 46 N egative phase sequence 43 7 9 1 Measurement checks 44 7 9 2 Characteristic and operating time for 46 gt N PS alarm 44 7 9 3 Operation of output relays for 46 gt N PS alarm 45 7 9 4 Characteristic and operating time for 46 gt gt N PS thermal trip 45 7 9 5 Checks for 46 gt
233. f voltage restrained overcurrent protection function In this mode itis more complex to determine the behaviour of the protection function during a fault Thus itis more difficult to co ordinate with the protection of feeders from the generator protection busbar This protection mode is however better suited to applications where there is a less significant phase phase voltage collapse at the generator terminals for a busbar fault This would be the case where a generator is connected to a busbar via a delta star step up transformer W ith indirect connection of the generator a solid phase phase fault on the busbar will only resultin a partial phase phase voltage collapse atthe generator terminals For such a fault the minimum phase phase voltage seen by the LGPG111 would be 50 of the nominal voltage when the generator transformer impedance is very small in relation to the generator synchronous reactance as it would be and the generator was initially at the no load level of excitation To improve the sensitivity of the voltage estrained overcurrent protection function for HV phase phase faults fed via a Yd1 or Yd11 step up transformer the appropriate voltage signal transformation facility should be switched in as part of the LGPG111 settings Use of this feature will also de sensitise the voltage restrained protection function to an HV earth fault which would yield a low phase phase voltage on the generator side of the step up transformer R
234. fault operating consideration for the voltage dependent protection function need only be a three phase fault where the negative phase sequence thermal protection function is applied The required protection fault setting K I gt would need to be less than 0 25 p u if the longest feeder from the generator bus is very short and E 1 0 p u with X 2 0 p u The under voltage switching threshold setting Vs should be selected so that switching does not take place with the minimum possible phase phase voltage for single phase to earth fault conditions For a single phase fault the minimum possible phase phase voltage would be for a close up earth fault on a solidly earthed power system where the voltage could fall to 57 of the nominal level The voltage setting should also be set above the maximum phase phase voltage for any element required to operate for a remote end feeder fault The steady state voltage seen by the LG PG 111 for sucha fault and under the conditions mentioned earlier can be deduced as follows E 3 nR 2 nxp nRJ2 X X 2E 3 nR nX 2 A 2nR 2 X X_ 2nX As already mentioned where the negative phase sequence thermal protection function is set and enabled a remote three phase fault need only be considered when determining the voltage threshold setting Vs Three phase fault Vp Phase phase fault V Service M anual R5942B LG PG111 Chapter 3 2 6 2 Page 33 of 75 Application o
235. ferential R5942B Chapter 6 Page 63 of 91 Table 38 Bit flag assignment read right to left of the scheme logic inputs N ote 16 37 Output OR matrix The names of the logic inputs bits 0 to 11 can be changed in the input output labels section N egated logic inputs bits 4 6 8 amp 10 are indicated by a prefixed minus In a similar fashion the negated output from the voltage balance protection VT failure bit 13 is prefixed by a minus A subtitle cell for the remote system only all the scheme logic output OR matrix settings are indented below this 16 38 to 16 69 Output O R matrix settings Thirty two cells one for each of the thirty two logic lines of the scheme logic output O R matrix A bit set to 1 represents a connection in the matrix All these settings are password protected The bits are summarised in Table 37 Service M anual R5942B Chapter 6 Page 64 of 91 7 18 Input output labels Item Front Panel Remote Access ame T 17 0 INPUT OUTPUT Input Output Labels LABELS E 17 1 Digital Input Labels 17 2 Input 6 Input 6 Input 6 Input 6 17 9 Input T3 Input Iss Input r3 Input 13 17 10 Output Contact Labels 17 11 Output 1 Output 1 Relay 1 Relay 1 li a 17 25 Output 15 Output 15 Relay 15 Relay 15 i Table 39 The LGPG111 s Input output labels Section of its menu Allows all the application dependent inpu
236. for external faults which may lead to a transient differential current as a result of transient asymmetric CT saturation Stability is assured through the use of a through current bias percentage estraint technique The differential protection function operating characteristic is depicted in Figure 8 For general applications the load current bias slope K1 should be set to zero and the through fault bias slope K2 should be set to 150 The general CT requirements have been determined on this basis through conjunctive testing This will ensure constant differential protection function sensitivity with varying load current The recommended setting for the break point in the bias characteristic Is2 is 1 2In so that sensitivity will be maintained under full load conditions with a low level winding fault There can be a traditional preference for applying highimpedance generator differential protection as opposed to biased protection This preference may be based on maintaining a constant protection sensitivity with varying load current and on being able to use smaller CT s with earlier relay designs W ith the LGPG111 load current bias slope K1 set to zero there would be no advantage in using high impedance protection from a sensitivity pointof view If however high impedance protection is a specified requirement for a particular application it would be possible to implement this form of protection using the LGPG111 by virtue of the fact
237. for other protection functions could either share a set of differential protection main CT s or use another set W here a significantly rated unit transformer is teed off within the required zone of generator differential protection such that an LV auxiliary system fault would yield sufficient primary current to cause unwanted differential protection operation it will be necessary to cover the additional primary connection with an additional set of differential protection CT s This additional set of CT s should be connected in parallel with the generator terminal CT s see Figure 5 All CT s used for the differential protection function must be of equal ratio Any deviation in tee off CT ratios must be dealt with using adequate interposing CT s of Suitable ratio In the case of some pumped storage arrangements or gas turbine start up arrangements an in zone variable frequency supply connection would also need to be addressed in the same manner Failure of stator windings or connection insulation can result in severe damage to the windings and stator core and more widespread damage to winding insulation The extent of the damage will be a function of the fault current level and the duration of the fault Protection should be applied to limit the degree of damage in order to limit repair costs For primary generating plant high speed disconnection of the plant from the power system is also necessary to maintain system security For gener
238. for the generator bus it may not be possible to ensure operation of the generator voltage dependent protection function for a remote end feeder fault until the additional source has been disconnected by its own protection W here the additional source is another parallel generator it may be that neither generator can respond to the remote fault with voltage dependent protection In such cases the generators would have to be tripped by delayed under voltage protection for a remote persistent fault see Section 2 10 For phase phase faults tripping may occur earlier via the negative phase sequence thermal protection function of LG PG 111 if itis set and enabled The minimum fault current for a remote end multi phase fault on a feeder can be determined as follows This calculation is based on the no load excitation being applied and on no field forcing or AVR action during the fault Service M LG PG111 anual R5942B Chapter 3 Page 32 of 75 Three phase fault Ip AJ nRa X nX Phase phase fault It BE 2nR X X X_ 2nX W here Minimum generator primary current seen for a multi phase feeder end fault E No oad phase neutral internal e m f of generator X Direct axis synchronous reactance of the generator X Negative phase sequence reactance of the generator R Feeder positive phase sequence resistance X Feeder positive phase sequence reactance n Number of parallel generators The remote
239. four arrow keys with the SET and RESET keys are used to browse the relay s menu and to change settings Differential System data Enabled Measurements Is1 0 05A Generator Records k1 0 Protection Differential 1 2A Earth fault 150 Overcurrent Field failure Figure 8 Illustration of the operation of the front panels arrow keys during menu browse In the menu browse mode the keys of the key pad have the following principal functions The T amp J arrow keys are used for selection They allow the titles and section contents to be browsed by selecting the next or previous cell to be displayed The selection process loops around from end to beginning and vice versa The arrow keys are also used in selecting or changing cell values during setting mode The arrow key is used as a selector It enables section title browsing from the default display and allows the content of a section to be browsed by selecting its title In this respect it may also be thought of as a turn to key With a cell from a section displayed pressing the arrow key enters setting mode for it The lt arrow is used to back out of a section to the section title browse and from here to the default display In this respect it may be thought of as a turn back key It cannot be used to cancel back out of setting mode However in some sections if settings have been altered backing out of the section will cause a setting confirmation st
240. frequency stage with associated timer Should be set above the sustainable over frequency level with a time delay sufficient to overcome transient over frequencies following load rejection The over frequency protection function of LGPG111 utilises the AC voltage input signals as the frequency measurand A single time delayed stage of over frequency protection is offered by LGPG111 with an over frequency threshold setting F gt and a time delay setting t M oderate over frequency operation of a generator is not as potentially threatening to the generator and other electrical plant as under frequency running and action can be taken at the generating plant to correct the situation without necessarily shutting down the generator As already described in Section 2 12 operation of a high speed turbine generator away from nominal speed can lead to blade resonance that if prolonged or accumulated could lead to turbine damage As discussed in Section 2 7 2 severe Service M anual R5942B LG PG111 Chapter 3 2 14 Page 57 of 75 over frequency operation of a high speed generating set could result in plant damage as a result of the high centrifugal forces that would be imposed on rotating components O ver frequency running of a generating set arises only when the mechanical power input to the alternator is in excess of the electrical load and mechanical losses The most common occurrence of over frequency is after substantial loss of
241. g Is Invalid Occurs when an Incorrect password has been entered or too many analogue channels have been selected in the disturbance recorder setup Press the lt key to abort the setting change and return to setting mode Not A Setting Occurs when the key has been pressed for a cell which is nota setting Press key to abort this action Not A Setting View Occurs when the key has been pressed for a binary flag value cell which is nota setting A further press of the enables the labels of each binary bit flag to be viewed The lt key aborts the action Press SET To Confirm Changes Occurs when leaving some of the sections in the menu in which a setting s has been changed O ptions are to re enter the section SET to update and RESET to ignore the setting change s Remote Setting In Progress The remote access system is changing a setting and itis not possible to change a setting locally at the same time The lt key will return to the cell s display Remote Setting In ProgressVie The remote access system is changing a setting and itis not possible to change a setting locally at the same time The key enables the labels of each binary bit flag to be viewed The lt key will return to the cell s display Alarm messages Alarm messages are categorised into five types and they are only available on the front panel during the alarm scan The display format of an alarm message is shown in the follow
242. g any outputs contacts The state of this cell is logged as an event record whenever the relay is reset and when the cell is changed Clear event records Allows the event records to be erased This cell is password protected and is not included in the setting transfer Service M anual R5942B LG PG111 Chapter 6 Page 33 of 91 Front Panel E Remote Access Clear Event Clear Event Records No Records Press SET To Clear Event Records Yes Clear All Record Table 12 States of the Clear Event Records Cell The effect of clearing all the event records has no effect on the alarm status on the LG PG111 s front panel but it will stop any events from being extracted remotely The cell allows the relay s event system to be purged after commissioning 2 8 Print Various reports can be printed on a parallel printer connected to the front panel parallel port The cell also reports the status of the printer when a reportis being printed The remote access setting transfer does not include this cell Table 13 summarises the cell s various states The first three are status indications and the remainder are requests for particular reports to be printed The printer busy status occurs when the busy signal into the parallel port is activated This will occur when the printer is O ff Line out of paper or has a full input buffer The busy message will return to printing when the busy signal i
243. g ranges Analogue inputs The module contains three standard current transformers three high sensitivity current Nominal 24 34V 48 54V 110 125V 220 250V Table 12 Status input voltage ranges for analogue and status input module transformers six transactors and five voltage transformers These interfacing transformers scale down the levels of the incoming signals and provide isolation The different types of transformers are used to optimise the performance of the protection functions whilst maintaining a compact design The output of each of the interfacing transformers is filtered by an anti aliasing filter and multiplexed by one of three analogue multiplexers into a sample and hold filter This hasa x1 and x8 gain control to increase the dynamic range of the input signals Data conversion is performed by a 12 bit analogue to digital converter The 12 bit data is 2 s complemented and sign extended to 16 bits before being transferred to the microcomputer module for processing In addition to multiplexing the analogue signals the three multiplexers are also connected to two DC signals 5V and OV These are used for checking the correct operation of the multiplexers sample and hold and data conversion circuitry Service M anual R5942B LG PG111 Chapter 5 5 6 2 5 6 3 5 6 4 5 7 Page 16 of 23 Status inputs Six optically isolated logic status inputs are provided which are rated at the auxiliary DC supply
244. gative phase sequence current could result in thermal protection tripping and generator shutdown This enables system operators to be made aware of a condition that may eventually lead to a shutdown if the offending power system condition is not dealt with Some protective relays have also been provided with local and or remote negative phase sequence current indication facilities The LG PG 111 is provided with a definite time negative phase sequence overcurrent alarm stage Itis also possible to configure the LG PG111 to locally display the measured negative phase sequence current as well as to provide remote indication via the relay s serial communication ports The independent alarm current threshold setting 12 gt and the adjustable time setting t gt should be set to avoid unwanted alarms during short periods of very light unbalanced operation These typically might occur during delayed clearance of faults well within the power system being fed A typical alarm current setting 12 gt would be 70 of the thermal trip setting 12 gt gt The alarm time delay t gt would have to be set well above system fault clearance times and any single pole auto reclose dead times whilst not unnecessarily reducing the time available to take corrective action to prevent thermal element tripping The final time setting may have to be arrived at after commissioning starting with a low value in order to determine the minimum delay that will not resu
245. generator s per unit current thermal capacity constant in seconds l The limiting continuous maximum temperature 6 would be reached according to the following currenttime relationship acme IS the generator s per unit continuous maximum I rating or o 2 1 T 2 C Ocye C 1 M lcyp From the above the time for which a level of negative phase sequence current in excess Of l cmg Can be maintained is expressed as follows K 2 t g Log 1 f a 2 l2CMR 2 The LGPG 111 negative phase sequence protection function main element offers a true thermal characteristic according to the following similar formula 12 gt gt 2 t K Log 1 2a I2 gt gt l7 Note All current terms are in per unit based on the relay rated current In To obtain correct thermal protection the relay thermal current setting 12 gt gt and thermal capacity setting K should be set as follows E flc I2 gt gt lon X x In P 2 K K x tH ol P Service M LG PG111 anual R5942B Chapter 3 Page 46 of 75 W here 12 gt gt Required relay maximum withstand A K Required relay thermal capacity constant s l K Generator thermal capacity constant s lac l CT primary current rating A Generator per unit maximum withstand 2cmr Generator primary fulltoad current A In Relay rated current A As with all inverse time protection elements it is necessary to
246. gt N PS thermal trip reset time 47 7 9 6 Operation of output relays for 46 gt gt N PS thermal trip 49 7 10 81U Under frequency 49 7 10 1 Measurements 49 7 10 2 Characteristic and operating time 49 7 10 3 Operation of output relays 51 7 11 810 Over frequency 51 7 11 1 Characteristic and operating time 51 7 11 2 Operation of output relays 52 7 12 Under voltage 53 7 12 1 Measurements 53 7 12 2 Characteristic and operating time 53 7 12 3 Operation of output relays 54 7 13 Over voltage 54 7 13 1 Measurements 54 7 13 2 Characteristic and operating time 54 7 13 3 Operation of output relays 55 7 14 60 Voltage balance 55 7 14 1 Measurement checks 56 7 14 2 Characteristic checks for 60 VB Prot 56 7 14 3 Characteristic checks for 60 VB C omp 56 7 14 4 Operation of output relays for voltage balance prot 57 Service M anual LG PG111 9 1 10 10 1 10 2 11 12 12 1 13 13 1 14 LO GIC IN PUT STATUS CHECKS CON TACT TEST Relay inoperative alarm SCHEME LOGIC TESTS Example scheme logic tests Procedure for testing the scheme logic W IRING CHECKS STABILITY CHECKS FOR 87G GEN ERATO R DIFFEREN TIAL Stability of sensitive directional earth fault ON LOAD CHECKS Phase angle compensation for the power measurement FIN AL SETTING CHECKS R5942C Chapter 8 Page 6 of 66 58 59 59 60 60 62 63 64 65 65 65 65 Service M anual R5942C LG PG111 Chapter 8 Page 7 of 66 Important
247. gt setting into the V input terminals B27 B28 Vary the frequency to check the relay s pick up and drop off values Pick up frequency F gt with a 0 5Hz tolerance Drop off frequency F gt 0 2 Hz with a 0 5Hz tolerance Service M anual R5942C LG PG 111 7 11 2 Chapter 8 Page 52 of 66 Measurement of operating time with a variable frequency supply Arrange the variable frequency supply to step change the frequency from less than F gt to above 1 1xF gt Alternatively this can be accomplished by changing the voltage connection to the relay from a system supply to the variable frequency supply set at 1 1xF gt A single pole quad throw switch can be used for this purpose Record the operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check that ALARM Protection 810 OF appears on the display ignore other alarms Reset all alarms Record the operating time O perating time tl with a 5 tolerance 10 to 40mS Measurement of F gt without a variable frequency supply Inject rated voltage with rated frequency into relay terminals B27 B28 Decrease the setting F gt 0 1 Hz ata time until the relay operates and then record the setting F gt setting injected frequency with a 0 5 Hz tolerance W ith the relay operated increase the setting F gt to check when the output contacts reset Record the setting which causes the relay to reset F gt setting
248. h protection functions have been enabled and disabled Generator differential Settings for the differential protection function Service M anual LG PG111 9 0 10 0 13 0 14 0 15 0 16 0 17 0 18 0 19 0 20 0 21 0 R5942B Chapter 6 Page 25 of 91 Earth fault protection Settings for stator earth fault neutral displacement and sensitive directional earth fault protection functions Voltage dependent overcurrent Settings for the voltage dependent overcurrent protection function Power protection Settings for the reverse and low forward power protection functions Also includes a setting to compensate for any phase error between the system CT amp VT Frequency protection Settings for two under and one over frequency protection functions Voltage protection Settings for under and over voltage protection functions plus a voltage balance or VT fuse failure function N egative phase sequence Settings for the negative phase sequence protection Field failure Settings for the field failure protection function Scheme logic Contains all the settings for the scheme logic plus settings for specifying which outputs are latched or self reset which outputs trigger alarm events and which outputs trigger a trip event Input output labels Allows all the application dependent inputs and outputs to be given appropriate identifier labels Remote communications Configuration settings for the
249. he rate of heat dissipation is such that damaging temperatures are not reached within individual rotor components All synchronous machines will be assigned a continuous maximum negative phase sequence current 1 per unit rating by the manufacturer For various categories of generator minimum negative phase sequence current withstand levels have been specified by international standards such as 1EC60034 1 and ANSI C50 13 1977 1 The 1EC60034 1 Figures are given in Table 3 W here a generator has a high continuous negative phase sequence current withstand level as in the case of typical salient pole machines it may be decided that there would be no practical circumstances in which this level could be exceeded by any events on the power system that is to be supplied In such cases it would not be essential to set and enable the N PS protection function The N PS protection function can however offer a better method of responding to an uncleared asymmetric fault at the remote end of a feeder from the generator bus As already mentioned in Section 2 6 it may be difficult to set the voltage controlled overcurrent protection function to shutdown the generator for a remote fault and still be able to maintain co ordination with feeder backup protection for a close up 3 phase fault Service M anual R5942B LG PG111 Chapter 3 Page 44 of 75 Generator type Maximum L I for Maximum L yt continuous operation for operation under fault conditions
250. he Clock Sync input will pull the clock to the nearest hour or half hour ALTERNATIVE SETTING GROUP The LG PG 111 provides two setting groups a primary and an alternative generally referred to as Group 1 and Group 2 These setting groups include all the protection and scheme logic settings Settings can be changed from one group to another without significant interruption to the internal operation of the relay functions The alternative setting group is optional If itis disabled then the group 2 settings will not be available from the menu system The active setting group can be selected by one of the following methods 1 By controlling two setting group select logic inputs or 2 By a password protected command setting or 3 By issuing a remote access command to the LGPG111 The first method using logic inputs is mutually exclusive of the other two methods collectively referred to as the menu methods A setting Select Setting Group is used to select either the logic input or the menu method for controlling the setting group selection If the user has selected to use the menu method to change the setting group then the relay will also be able to respond to a global setting group change command issued by the remote access system This allows all the relays connected to the communication system to change to a specific setting group Service M anual R5942B LG PG111 Chapter 4 9 9 1 9 2 Page 43 of 50 NON PROTECTION
251. he chapter RELAY IDENTIFICATION Model numbering The complete identification for the relay is described by a 16 character model number The model number is broken down into a number of fields which are detailed below Issue See Model List ofo o gt riginal oftware Change MC Phase 1 mods 21 11 95 MC Phase 2 mods module 5 amp 6 VT amp CT Ratings nglish rench m o erman panish VT amp CT Ratings 10V 1Amp 10V 5Amp i Supply Voltages 4 27Vdc 0 34Vdc 8 54Vdc 10 125Vdc 20 250Vdc VX1 Auxiliary Supply Voltages 4 27Vdc 0 34Vdc 8 54Vdc 10 125Vdc 20 250Vdc Flush Panel Rack ing File Reference g D 5 5 S D a e 5 a NMN aje Digital Integrated M ulti Function G enerator Protection m m m VT amp CT Ratings O VT amp CT Ratings O VX2 Auxilia VX1 Auxiliary Supply Voltages See note 1 l1to4 56 7 8 9 101112131415 note 1 The old model number formatis shown in brackets Table 1 Model number field definitions Service M anual R5942B LG PG 111 2 2 2 3 2 4 Chapter 5 Page 6 of 23 Module numbering M odules are identified by a 10 character code This coding which is known asa 2 alpha coding is of the form GM mmmm nnn A The identifier is marked on a strip fitted into the lower front extrusion of the module The first two characters are always GM for the M
252. he current setting at the normal level of voltage I gt should be set to have a primary operating value in excess of the maximum required level of generator load current The actual maximum load current should be divided by 0 95 to obtain a satisfactory margin for measurement accuracy t TMS x The current setting multiplying factor K governs the protection function setting under low voltage conditions The current setting multiplying factor should be set to give a primary operating current less than 50 of the minimum steady state fault current for a multi phase fault at the remote end of a feeder fed from the generator bus with the generator being the only source This ensures that protection failure or breaker failure for the faulted feeder will not result in the generator persistently feeding current to an uncleared feeder fault The voltage controlled protection function should co ordinate with outgoing feeder protection for a feeder fault under minimum plant conditions The most onerous case to consider is that of a close up three phase fault on a feeder where there would be almost a full voltage collapse seen by the LGPG111 W here co ordination is difficult to achieve and where KCGG KCEG feeder overcurrent relays are employed start contacts of the feeder overcurrent relays should be used to interlock operation of the LG PG 111 voltage dependent protection function as described in Section 3 4 W here there is more than one source
253. he event of transient CT spill current arising The required time setting may need to be in excess of the minimum 0 5s setting and would have to be arrived at by judgement or by trial switching of transformers onto the generator busbar A core balance CT is a much more preferable option to avoid the transient spill problem with line CT s Voltage dependent overcurrent protection function 51 V Summary Provides back up protection for uncleared downstream faults The protection operating mode can be configured to be a simple overcurrent a voltage controlled overcurrent or a voltage restrained overcurrent function In any of the modes of operation the associated time delay can be either definite time or standard inverse IDM T The voltage dependent overcurrent protection must be time graded with down stream overcurrent protection W here overcurrent relays with start contacts are used on outgoing feeders time grading can be achieved by blocking the opera tion of the voltage dependent overcurrent protection The reset time of the protection can be set to be instantaneous or time delayed A time delayed reset can be used to provide better time grading with downstream electro mechanical protection and to detect intermittent faults In the simple overcurrent mode the system voltage has no effect on the current setting of the protection At normal system voltage the current setting should be 5 above full load current W hen a faul
254. he normally open relay inoperative alarm contacts close terminals G1 amp G 3 If they close then the main microprocessor is functional Try establishing communications with the relay preferably by one of the rear communications ports If communications can be established then both the main microprocessor and slave communications microprocessor are functional Service M anual R5942C LG PG 111 3 3 1 3 2 3 3 3 4 3 5 Chapter 7 Page 8 of 14 OPERATIONAL FAILURES Should the relay be suspected of being faulty each module can be tested to verify that itis working correctly Faulty modules can therefore be identified and replaced Power supply checks Testing the power supply is discussed in section 2 1 Check the voltage rails brought out on the parallel port as discussed in section 2 2 and that the power supply fail contacts operate correctly when the supply is switched on and off A faulty power supply can also be the cause of spurious resets Main microprocessor checks The microprocessor is extensively tested during the power on diagnostics To verify that itis working correctly switch off the DC supply to the relay Then switch it back on after a few seconds and observe the cold start diagnostic test messages on the front panel display A lockout error as shown in Chapter 6 Section 9 2 indicates a faulty microcomputer and serial communications module The non volatile EEPROM memory in the microproce
255. he operation of the phase A element of the generator differential function ALARM Relay O P Output 7 is an output relay alarm which indicates the operation of the output relay contact labeled Output 7 Note the names of the outputs and the logic inputs can be set by the user To scan and reset alarms repeatedly press the lt key until the relay displays ALARM Press the Accept Read key to successively scan through the alarm messages until the display shows Press RESET To Clear Alarms Press the RESET key to clear all the alarms thus also resets any latched outputs The Under Voltage Low Forward Power and Under Frequency protection functions are suspended if there is no voltage or current input into the relay on its frequency tracking inputs of Vp V or ab Service M anual R5942C LG PG111 Chapter 8 5 3 Page 15 of 66 The default display on the relay is Generator Protection or Local Settings Unlocked if the relay s password has been entered through the front panel user interface N ote the default display can be set by the user Setting the relay In order to enter the settings from the setting schedule you should understand the description of the user interface in chapter 6 particularly the front panel interface methodology if this is to be used If a PC running a suitable program is to be used then the program s instruction book should be consulted especially if th
256. he print function prints whatever records are available at the end of printing the string End of Report Is printed LGPG RELAY lt Not Defined gt Serial Number 0000000 Printed on Tue 1994 Aug 23 P63 35 2L9 EVENT RECORDS Sat 1994 Jan 01 00 00 00 014 Events Relay Power On Sat 1994 Jan 01 00 00 00 014 Events Real Time Clock Invalid Sat 1994 Jan 01 00 00 00 076 Events Group 1 Selected Tue 1994 Aug 23 08 05 51 000 Events Real Time Clock Valid Tue 1994 Aug 23 W252 83293 Relay Output Change Relay Inoperative Alarm Tue 1994 Aug 23 16 05 33 188 Exceptions Analogue Module Fail Tue 1994 Aug 23 16 06 28 981 Events Relay Warm Reset Tue 1994 Aug 23 16 06 29 043 Events Group 1 Selected Tue 1994 Aug 23 16 30 48 541 Events Local Password Removed Wed 1992 Jan O1 05 39 05 956 Events Local Password Restored Tue 1994 Aug 23 16 43 15 924 Relay Output Change O Voltage Trip Tue 1994 Aug 23 16 43 15 924 Protection 59 Over Voltage Service M anual LG PG111 13 Tue 1994 Aug 23 Fault Record 16 45 14 599 Protection 87G Generator Differential AB 81U 1 Under Fre quency 81U 2 Under Freque 27 Under Voltage 59 Over Voltage gt 51N gt Stator Ear 40 Field Failur Relay Output St O Voltage Trip Trip Logic Input Sta Scheme Output Active Setting Ta Ib Lee Ia Diff Ib Diff Ic Diff Ia Mean Bias Ib Mean Bia
257. he rear of the relay CT shorting switches are fitted where required There are also two connectors mounted on the communications isolation module These are a 25 way D type female connector which is an isolated RS232 port using IEC870 protocol and the other is a 3 terminal screw connector which is an isolated RS485 port using K Bus protocol Both are designed for permanent remote connection There is no back plane wiring in the relay All inter module wiring is via a 64 way ribbon cable bus the I O bus behind the hinged front panel By this means all the electronic signals and internal power rails between modules are spaced as far as possible from the incoming wiring The I O bus runs along the front of modules and is terminated on the front panel Connections are made to the modules by two part insulation displacement connectors IDC Modules are locked in position by an aluminium screen mounted on the rear of the front plate The microprocessor module controls all the modules on the I O bus CASE DESCRIPTION The single tier 4U 178mm high rack or panel mounting case has been designed to provide adequate screening for high speed electronic circuitry The whole case including the front cover is made in steel The relay is of modular design and modules are located in grooves Interposed between the plastic grooves and the outer case are two full size upper and lower aluminium plates which are insulated from the outer case Each module has
258. he set time command has no effect when the K Bus serial link is used in con junction with a KITZ101 Early models of the KITZ101 were designed to use the set time command for the sole purpose of setting its internal real time clock and as a result did not pass the command onwards Contact ALSTOM T amp D Protec tion amp Control Limited to arrange for an upgrade 2 Cannot change settings in the remote user interface The remote setting cell in the Remote Communications section of the menu should be set to Enabled to allow remote change of settings 3 The relay s remote access menu appears different after a setting transfer This will be the case if the setting transfer did not finish successfully To restore the menu to its proper arrangement access the now visible communication system column section of the menu Set the transfer mode cell to No and exit from this section The relay s menu is now restored to its normal arrangement Chapter 8 Commissioning Instructions Service M anual LG PG111 Issue control R5942C Chapter 8 Page 2 of 66 Engineering document number 50005 1701 108 Issue Date _ Author Changes AP February 1995 Dave Banham Original BP February 1995 Dave Banham Maximum continuous current rating was incorrectly quoted as 4 instead of 4xln in Sections 5 3 2 and 5 11 4 CP June 1995 Dave Banham Minor Corrections N PS protection test instructions updated to
259. hich the ADC will saturate ADC saturation effect causes the relay to measure a smaller current magnitude than the actual value but this is unlikely to degrade the differential protection performance for internal faults or cause discrimination problems for external faults Figure 2 Generator differential typical input connection Phase A 1A transactor is a transformer with an air gapped core The air gap increases the inductance and saturation point which allows the transactor to cope with large through currents in a relatively small space A transactor behaves as a transformer loaded with a reactive shunt and effectively produces a secondary e m f proportional to its primary current However there is a quadrature relationship between the primary current and the secondary e m f due to the effective secondary reactive shunt In some respects the secondary e m f can be seen to be proportional to the primary di dt Service M anual R5942B LG PG111 Chapter 4 2 1 2 2 1 3 2 1 4 2 135 2 1 6 Page 9 of 50 Earth CT inputs Two CT s are used for the earth fault protection as shown in Figure 3 The input measures the neutral to earth current of the generator The input is used for the stator earth fault protection function and as the polarising quantity for the sensitive directional earth fault function The quai INpUt measures the residual current at the line end of the generator The input is used as the operating
260. hris Hodgson Protection summaries added Publicity Stator earth fault CT requirements corrected Service M anual R5942B LG PG111 Chapter 3 Page 3 of 75 CONTENTS 1 IN TRO DUCTION 5 Tal Generating plant 5 I 2 Protection of generators 6 Tea LGPG111 integrated protection 7 1 4 LGPG111 non protection functions 9 2 APPLICATION OF INDIVIDUAL PROTECTION FUNCTIONS 11 2 1 LGPG111 protection functions 11 2 2 Generator differential protection function 87G 11 2 3 Stator earth fault protection function 51N 19 2 3 1 Application to a directly connected generator 20 2 3 2 Application to an indirectly connected generator 20 2 4 N eutral voltage displacement protection function 59N I 59N 2 24 2 4 1 Application to a directly connected generator 24 2 4 2 Application to an indirectly connected generator 25 2 5 Sensitive directional earth fault protection function 67N 26 2 6 Voltage dependent overcurrent protection function 51V 28 2 6 1 Application of the voltage controlled overcurrent protection function 30 2 6 2 Application of voltage restrained overcurrent protection function 33 2 7 Reverse power and low forward power protection functions 32R 32L 35 2 7 1 Reverse power protection function 32R 35 2 7 2 Low forward power protection function 32L 40 2 8 N egative phase sequence thermal protection function 46 42 2 9 Field failure protection function 40 47 2 10 Under voltage protection function 27 51
261. ial communications board The serial communications board is designed to remove the time critical elements of the serial communication protocols The board uses an Intel 87C 196 microprocessor which is controlled by the main microprocessor module and which in turn controls a dual channel serial communications controller The board is linked to the microcomputer via the I O bus and also directly connects to the isolation module mounted in the rear of the relay A choice of 3 ports is available through the LGPG111 s user interface O ne is on the front panel and the other two are at the rear of the relay The front serial port is a non isolated RS232 port using the IEC870 protocol for communications Connection to this port is made via the I O bus with only transmit and receive signals being available the portis only suitable for temporary connection during commissioning and testing The other two serial ports are an RS232 port using IEC870 protocol and an RS485 port using K Bus protocol Access to these to ports is via the isolation module which allows for permanent connection Isolation module Module Number GM0100 The module is made up of one PCB and is mounted into the back of the case The isolation module provides isolation for the two rear mounted serial communications ports and allows these ports to be permanently connected to serial communications networks or modems etc K Bus connection K Bus requires a twisted pair screened ca
262. iary DC supply voltage Vx 2 To reduce power dissipation caused by current flowing in the isolation circuitry a strobing technique is adopted which only allows Module M odel number number issue letter GM0022 A to C GM0111 D onwards current to flow into the circuitry when the status inputs are being read Nominal Operative Range Maximum Withstand 24 27V 19 2 324V 36 5 V 30 34V 24 40 8V 45 9 V 48 54V 38 4 64 8 V 72 9 V 110 125V 88 150V 220 250V 176 300V Table 10 Status input voltage ranges Connections to external wiring is made via a 28 way MIDO S connector Terminal allocation of the input module is given in Table 11 The input function assignment is user definable through the scheme logic settings as described in chapter 4 The module is powered from the 6 5V rail of the I O bus Analogue and status input Module number G M0105 Service M anual R5942B LG PG111 Chapter 5 Page 15 of 23 Terminal No Description M enu Ref 1 Input 6 User Definable 5 p Input 7 User Definable 6 m Input 8 User Definable 5 6 1 T Input 9 User Definable 14 ee Input 10 User Definable 19 Input 11 User Definable ee ee 23 Input 12 User Definable ee 28 Table 11 Terminal allocation of the status input module Two AC input ratings are available 1A 110V 5A 110V Four DC voltage variations are available covering the followin
263. ic potential as the equipment by touching the case 2 Handle the module by its front plate frame or edges of the printed circuit board Avoid touching the electronic components printed circuit track or connectors 3 Do not pass the module to another person without first ensuring you are both at the same electrostatic potential Shaking hands achieves equipotential 4 Place the module on an anti static surface or on a conducting surface which is at the same potential as yourself 5 Store or transport the module in a conductive bag Service M anual R5942A LG PG111 Chapter 2 3 1 31l 3 1 2 Page 5 of 6 If you are making measurements on the internal electronic circuitry of an equipment in service itis preferable that you are earthed to the case with a conductive wrist strap W rist straps should have a resistance to ground between 500kW 10MW Ifa wrist strap is not available you should maintain regular contact with the case to prevent a build up of static Instrumentation which may be used for making measurements should be earthed to the case whenever possible More information on safe working procedures for all electronic equipment can be found in BS5783 and IEC 60147 0F Itis strongly recommended that detailed investigations on electronic circuitry or modification work should be carried outin a Special Handling Area such as described in the above mentioned BS and IEC documents UNPACKING AND INSTALLING Care must be ta
264. ic is illustrated in Figure 24 27 and 81U Inhibit Input 81U 1 Trip 81U 2 Trip 810 Trip Figure 24 Logic diagram for the under and over frequency functions Service M anual R5942B LG PG111 Chapter 4 3 10 2 3 11 3 11 1 Page 33 of 50 Settings and characteristic The settings provided by these functions are as follows Under frequency Fl lt Firstthreshold setting tl Timer 1 setting F2 lt Second threshold setting t2 Timer 2 setting O ver frequency F gt Threshold setting t Timer setting The characteristics are shown in Figure 25 Fl lt Frequency Frequency a Under frequency b O ver frequency Figure 25 Characteristics for the under frequency and the over frequency elements Voltage balance 60 G eneral description A voltage balance function is designed to detecta VT fuse failure The function works by comparing the secondary voltages from two sets of VT s or from two separately fused circuits of the same VT The voltage balance function provides three outputs to the scheme logic one output to indicate protection VT fuse failure another output to indicate comparison VT fuse failure The inverse of the protection VT fuse failure output can be used to block other voltage based functions which might be affected by the apparent loss of voltage due to a VT failure The function is executed approximately every 20ms Two consecutive calculations are required to confirm a
265. ically and displayed on the screen as they occur They can also be stored on to disk and printed later Disturbance recorder Disturbance records can be extracted and stored for further analysis Itis also possible for the access software to detect the presence of disturbance records as they occur and extract them automatically Remote change of settings If the remote setting change facility is enabled in the relay then settings can be changed remotely Transfer settings from or to the relay The LGPG111 supports a setting transfer mode which allows a complete record of all the settings regardless of current configuration to be transferred The transfer mode also eliminates certain settings which are either irrelevant e g the printer control cell or inappropriate to transfer e g time amp date setting cell The individual descriptions of the menu cells indicate which cells are not included in the setting transfer Service M anual R5942B LG PG111 Chapter 6 Page 19 of 91 IEC 870 K Bus Transmission Speed 600 to 19 200 Bits per 64 000 Bits per second second Signal Levels RS232 RS485 Maximum Cable Length 15m 1000m Connections Singled ended Multidrop up to 33 connections Isolation for 1 minute 1kV rms rear port only 2kV rms Protocol IEC870 5 FT1 2 HDLC Character Size 8 data bits 1 even parity bit 8 data bits packaged by 1 start bit amp 1 stop bit HDLC protocol
266. ifferential currents due to saturation effects of the generator CT s To achieve fast fault clearance the differential protection is executed at approximately every 5ms which is four times more often than the other protection functions Two consecutive calculations are required to confirm a differential condition This together with the fault inception time produces an operating time of typically less than 30 ms Bias current calculation The function works on a per phase basis with one bias I and one differential current input l per phase as discussed in Section 2 1 1 page 8 The second bias Current is derived from these two measurements vectorially Ibias Ibias laiff The mean bias current Imean bias s the scalar mean of pias ANd Ibias _ lbias bas I mean bias ha To provide further stability for external faults the bias quantity used for each phase is the maximum mean bias current calculated from all three phases i e I mean bias max Max L cia ak d I b mean bias are ere Settings and protection characteristic The settings provided by the function are as follows Isl Differential current threshold Is2 Threshold for increasing the percentage bias K1 Percentage bias for Imean bias max lt Is2 K2 Percentage bias for Imean bias max gt s2 The tripping criteria are formulated as follows 1 For Imean bias max lt l52 lgiff gt K1xlmean bias max t S1
267. iliary Functions setting area Transformer Ratios setting area Disturbance Recorder setting area O utput Label setting area pee nena Remote Communications setting area Rone Comms pee eRe Alarm Record data area ae Record STEREO Fault Record data area Fault Record STEER RG Event Record data area Event Record Service M anual LG PG111 R5942B Chapter 6 Page 89 of 91 continued from previous page ALA Scheme Logic 2 Data corrupted in Current Rating copy area Generator Differential Group 1 setting area Generator Differential Group 2 setting area Voltage Dependent O vercurrent G roup 1 setting area Voltage Dependent O vercurrent G roup 2 setting area Power Protection Group 1 setting area Power Protection Group 2 setting area Frequency Protection Group 1 setting area Frequency Protection Group 2 setting area Voltage Protection Group 1 setting area Voltage Protection Group 2 setting area Negative Phase Sequence Group 1 setting area Negative Phase Sequence Group 2 setting area Earth Fault Group 1 setting area Earth Fault Group 2 setting area Field Failure Group 1 setting area Field Failure Group 2 setting area Scheme Logic Group 1 setting area Scheme
268. ine feed on processing a carriage return character and some will automatically Carriage return on receipt of a line feed character Printers which do this can normally be configured not to consult the instructions for your printer Printed titles are not underlined but have a line of underscores printed to the right The LGPG111 relies on a carriage return character to bring the print head to the start of the current line before it underscores titles The technique works on most printers 4 10 Relay contact test 1 The relay contact test can only be performed when the out of service LED is on The LG PG 111 must be brought out of service by inhibiting the scheme output in the Auxiliary Functions section of the menu before the output contacts can be manually tested The displayed state of the relay outputs does not correspond to the bit setting of the relay test The relay output status reflects the status of the scheme logic output This allows the scheme logic outputs to be monitored during injection testing of the protection without operating any of the output contacts Service M anual R5942C LG PG111 Chapter 7 Page 13 of 14 3 When there is a genuine fault with the LG PG 111 the Relay Inoperative Alarm contact will de energise and the out of service LED will be illuminated Because the relay is now out of service the relay contact test can be performed except that itis not possible to operate the relay inoperative alarm contac
269. ing Auxiliary Power Supply Test Polarity of Vx 1 and Vx 2 checked Measured VxX 1 gt V Vx 2 _ oo V Correct Relay power supply failure alarm checked LED s tested Secondary Injection Tests Service settings applied Model and serial number correct in menu System frequency correct in menu CT and VT ratios correctly entered Primary secondary display value selected correctly Alternative setting group enabled Secondary injection tests applied to group 1 or 2 YES YES YES YES YES YES YES YES YES YES NO NO NO NO NO NO NO NO NO NO YES NO YES NO YES NO YES NO YES NO 1 2 Service M anual R5942B LGPG111 Chapter 9 Page 17 of 52 87G Generator Differential Tests Sensitivity and Operating Time Element Expected Operating Measured Operating Operating Time Current Current _ a aitt i Le Correct Operation Of Output relays Measurements ested curent pa c p E Ik D s Bias Characteristic Isl Kl Is2 K2 Lower Slope Current Current Phase Injected Bias Current Expected Trip Measured Trip Upper Slope Phase Injected Bias Current Expected Trip Measured Trip Current Current A Service M anual R5942B LGPG111 Chapter 9 Page 18 of 52 Fault Record Checks Fault records match injected faults E Notes
270. ing illustration First line indicates the type of alarm ALARM Exception Analog Mod Fail Second line indicates the cause of the alarm Figure 13 Composition of the Alarm Scan message display Exceptional alarm messages This type of error is generally caused by the failure of hardware Service M anual R5942B LG PG111 Chapter 6 D552 Page 87 of 91 ALARM Exception e Out Of Service LED is on Uncalib Analog e Relay Healthy LED is off The analogue input module has not been calibrated or its vital calibration data has been corrupted and the protection is stopped The module must be re calibrated The analogue module should be returned to ALSTOM T amp D Protection amp Control Limited or to a recognised service centre for calibration ALARM Exception e Out Of Service LED is on Analog Mod Fail e Relay Healthy LED is off The analogue input module has failed and the protection is stopped Replace the faulty module The analogue module should be returned to ALSTOM T amp D Protection amp Control Limited or to a recognised service centre for repair and calibration ALARM Exception Calib Vector Err The compensation data in the analogue input module has been corrupted The protection remains in service but with reduced measurement accuracy The analogue module must be re calibrated or replaced by a spare at the earliest opportunity The module should be returned to ALSTOM T amp D Protection amp C
271. ings are indented below this 16 5 to 16 36 Input AN D matrix settings Thirty two cells one for each of the thirty two logic lines of the scheme logic input AN D matrix A bit set to 1 represents a connection in the matrix All these settings are password protected The bits are summarised in Table 38 Service M anual LG PG111 Bit FrontPanelName Remote Access Name 0 Input 13 Input 13 1 Input 12 Input 12 2 Input 11 Input 11 3 Input 10 Input 10 4 Input 9 input 9 5 Input 9 Input 9 6 Input 8 dnput 8 7 Input 8 Input 8 8 Input 7 dnput 7 9 Input 7 Input 7 10 Input 6 Jnput 6 11 Input 6 Input 6 12 60 VB Comp 60 Voltage Balance Comp 13 60 VB Prot 60 Voltage Balance Prot 14 60 VB Prot 60 Voltage Balance Prot 15 40 FF 40 Field Failure 16 67N SDEF 67N Sensitive Directional EF 17 59N 2 ND 59N 2 N eutral Displacement 18 59N 1ND 59N 1 N eutral Displacement 19 51N gt gt SEF 51N gt gt Stator Earth Fault 20 51N gt SEF 51N gt Stator Earth Fault 21 46 gt gt NPS 46 gt gt NPS Trip 22 46 gt NPS 46 gt NPS Alarm 23 59 OV 59 Over Voltage 24 27 UV 27 Under Voltage 25 81U 2 UF 81U 2 Under Frequency 26 81U 1 UF 81U 1 Under Frequency 27 810 OF 810 Over Frequency 28 32LLFP 32L Low Forward Power 29 32R RP 32R Reverse Power 30 51V 0C 51V Overcurrent 31 87G Gen Diff 87G Generator Dif
272. injected frequency 0 2Hz with a 0 5 Hz tolerance Measurement of operating time without a variable frequency supply W ith no voltage injected re apply the injection at the same time as starting a timer in to obtain the operating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check ALARM Protection 810 OF appears on the display ignore other alarms Accept all alarms Record the operating time obtained This test method will incur a timing penalty of between 100 and 200ms whilst the relay establishes a frequency measurement O perating time tl with a 5 tolerance 10 to 40mS Restore the original setting for F gt O peration of output relays Inject rated voltage with rated frequency into relay terminals B27 B28 to operate the Service M anual R5942C LG PG111 Chapter 8 7 12 7 12 1 7 12 2 Page 53 of 66 810 change setting F gt if necessary Check the operation of the LGPG111 s output relays against the scheme logic settings Record the output relays operated Restore the original Scheme Logic settings if changed Restore the original setting F gt if changed Under voltage A single element three phase undervoltage detection function is provided It primarily used for the back up of the speed control governor and the automatic voltage regulator Enable the 27 Under Voltage protection only If necessary change the scheme logic input matrix so that
273. ion function has been assigned two relay outputs for circuit breaker tripping a non atched contact and a latched contact W here itis not required for a particular protection function to initiate a circuit breaker trip via a latched contact this allocation can be removed from the scheme logic CURRENT TRANSFORMER REQUIREMENTS The current transformer requirements for each current input will depend on the protection function with which they are related and whether the line current transformers are being shared with other current inputs W here current transformers are being shared by multiple current inputs the kneepoint voltage requirements should be calculated for each input and the highest calculated value used N ote should also be made of the effect on the current transformer requirements when using the LGPG111 at low frequencies See Section 1 3 Generator differential function Biased differential protection The kneepoint voltage requirements for the current transformers used for the current inputs of the generator differential function with settings of Is1 0 05In k1 0 Is2 1 2In k2 150 and with a boundary condition of through fault current lt 10In and X R ratio lt 120 is V 250 I R 2R R with a minimum of 34V W here Vk Minimum current transformer kneepoint voltage for through fault stability Relay rated current R Resistance of current transformer secondary winding Q R Resistance of a single
274. ion redundancy LGPG111 non protection functions In addition to being a versatile protection package the LGPG111 offers additional facilities by virtue of its digital design These facilities are listed below Electrical instrumentation with local remote display Fault records summary of reasons for tripping status of logic inputs relay outputs and fault measurements Event records Summary of alarms and relay events Disturbance records record of analogue waveforms operation of logic inputs and relay outputs Date and time tagging of all records Commissioning aids Remote communications High level of continuous self monitoring and diagnostic information Service M anual R5942B LG PG111 Chapter 3 Page 10 of 75 TRIP II TRIP MAIN II Figure 2 Complete protection redundancy using duplicate relays Service M anual R5942B LG PG111 Chapter 3 Page 11 of 75 2 APPLICATION OF INDIVIDUAL PROTECTION FUNCTIONS 2 1 LGPG111 protection functions The following protection functions are provided within the LG PG111 package Generator Differential protection 87G Stator Earth Fault protection 51N N eutral Voltage Displacement protection 59N Sensitive Directional Earth Fault protection 67N Voltage Dependent O vercurrent protection 51V N egative Phase Sequence Thermal protection 46 Field Failure protection 40 Reverse Power protection 32R Low Forward Power protection 32L O ver Voltage
275. is AAAA A backup password is also available for each relay and can be used when the user password has been lost Please contact ALSTOM T amp D Protection amp Control Limited quoting the model and serial numbers of the relay for which a backup password is required Password protection can be re enabled if the particular access method is notin setting mode by resetting the password cell Disabling and re enabling password protection is logged as an event Each user interface has its own password locks entering the password in one system only unlocks that system and not both of them Remote Setting Change In any system which can be controlled remotely and particularly those accessed over the public telephone network there are bound to be concerns about unauthorised access In this respect there are two types of unauthorised access to be considered benign and malicious Benign unauthorised access is only a problem when public communications are used A hacker may stumble on the LG PG111 s modem telephone number and try to communicate with it However itis unlikely that communications with the relay would be established without specific knowledge of the protocol and format of the communications employed or a suitable access software tool the communications system is nota simple ASCII based interface Malicious unauthorised access results when a hacker has the means to communicate successfully with the relay and is intent on altering
276. is not provided with an independent set of secondary windings for broken delta connection a set of three single phase interposing VT s should be applied The interposing VT s should have their primary windings connected in star to the main VT secondary winding terminals and star point Their secondary windings should be connected in broken delta format to drive the neutral voltage displacement protection function Alternatively this protection function could be driven from a single phase VT connected between the generator winding star point and earth The voltage setting of the neutral voltage displacement protection function should be Service M anual R5942B LG PG111 Chapter 3 2 4 2 Page 25 of 75 set higher than the effective setting of current operated earth fault protection on any outgoing feeder from the generator bus The setting should also be higher than the effective setting of the sensitive directional earth fault protection applied to any parallel generator The effective voltage setting of any current operated earth fault protection may be established by multiplying the primary operating current of the protection by the generator grounding impedance and dividing by one third of the VT winding ratio in the case of a broken delta VT arrangement or by the actual VT winding ratio in the case of a single phase star point VT The second time delayed stage of protection 59N 2 should have a time delay that is set to co ordinate
277. is potentially faulty Re connect all the other modules and check the contact is still closed if it is now open repeat the test to isolate another potentially suspect module Re connect the suspect module and check the contact is now open This module should be replaced Front panel checks I 2 If the front panel s display is blank continue by checking the voltage rails on the parallel printer port as detailed in Table 1 If any one of the voltage rails is out of tolerance check the ribbon cable bus for shorts or breaks and replace the power supply module Itis possible to determine whether the display is powered and functional by observing very faint black squares on the top line for each character position The squares disappear when the DC supply is removed O bserving at an ob lique angle with a direct but not glaring light source can help A powered but blank display would suggest a problem with either the ribbon cable bus or the microprocessor module Tolerance 10 4 20 10 20 10 20 10 Table 1 Front panel parallel port voltages 110 125V amp 220 250V versions only Pin Voltage Rail Tolerance 25 ov Lek s 24V 10 19 19 5V 10 18 6 5V 10 20 19 5V 10 Table 2 Front panel parallel port voltages all other voltage versions Main microprocessor checks 1 W hen the DC auxiliary supply is applied to the relay check t
278. is provided This allows the 51V to make use of derived voltages with the same phase phase relationship as the HV side voltages If the Yd option is selected for the Voltage Vector Rotate setting the voltage dependen cies for the three overcurrent elements are as follows N ote that these quantities apply to both Yd1 and Yd11 step up transformers For l element Va Va J he For Ip element V Yo Vas For Ic element V Va Vac eiF EEPE ERER SE ENE HEERE Sigs setae fa yh O perating Time Seconds 10 UAE hfe ten han on tah pt oar ren Pe Sao Ci P a Pee e eed ee pe ERAN Se T es 3 EA A l T l BEO aaa a Current M ultiple of Setting Figure 15 Voltage dependent overcurrent standard inverse timing characteristic 3 6 Reverse power and low forward power 32R amp 32L 3 6 1 General description Both power functions calculate the A phase active power V xl xcos where 9 is the angle of Ja with respect to y The quantity y is derived from the Vab measurement scaled by V3 and phase shifted by 30 The quantity la is obtained Service M anual R5942B LG PG111 Chapter 4 3 6 2 Page 25 of 50 from the l sensitive INput This dedicated current input is designed to provide the required sensitivity for the power protection functions A compensation angle comp can be used to compensate for the phase angle error of the generator s CT with respect to
279. ising a steam turbo alternator when on turning gear could be extremely costly if a method of quickly tripping the generator breaker is not provided If a dead machine is energised from a live power system rotor currents will be induced and the machine will accelerate as an induction motor The induced currents in the rotor body and windings would be very high with the machine initially at standstill and could rapidly result in thermal damage unless the machine is designed for directon line run up as an induction motor possibly for starting a gas turbine prime mover The unexpected shaft rotation could also result in rapid mechanical damage if lubrication systems are not running or if a steam turbo alternator is on turning gear A number of the LG PG 111 s protection functions could respond to the inadvertent energisation of a dead machine The effective machine impedance during such energisation would be similar to its sub transient reactance and so the current drawn from the power system would be high Both the field failure and overcurrent protection functions could respond to the condition The reverse power protection function should also theoretically respond but the very high reactive component of stator current may prevent the power measuring element from responding All of these protection functions are normally arranged to initiate generator tripping via discrimination time delays such that tripping following energisation of a dead machine
280. itive directional earth fault protection function see Section 2 5 Direct tripping of this stage could be enabled in the group 2 settings with a minimum time setting of 0s The relay could be switched to adopt group settings when the generator circuit breaker is open via a normally closed breaker auxiliary contact acting on the group selection logic inputs inputs 3 and 4 This arrangement would offer fast earth fault protection if an earth fault occurs on a generator when itis not connected to the generator bus and when there is no need to co ordinate with the operation of any other earth fault protection This protection will also clear an earth fault on an unsynchronised generator that does not have its own earth connection Application to an indirectly connected generator For this type of application illustrated in Figure 5 the voltage operated stator earth fault protection function should be driven from the secondary winding of a distribution earthing transformer In the case of direct resistive earthing or of no deliberate earth connection the protection should be driven from a VT winding as described in Section 2 4 1 The voltage setting of the protection function should be set to 5 of the voltage that would be applied to the relay in the event of a solid fault occurring on one of the generator terminals This would offer approximately 95 coverage of the generator winding The voltage operated protection function might be used to co
281. jected Current l M easured Current Characteristic and Operating Time for 51N gt le gt t gt treset SI DT Measurement of le gt Expected Pick up Value Measured Pick up Value Measured Drop off Value Li Measurement of Time Delay Characteristic Expected Time Delay Measured Time Delay Operation Of Output Relays for 51N gt Correct Operation Of Output relays Characteristic And Operating Time For 51N gt gt le gt gt t gt gt Measurement of le gt gt Expected Pick up Value Measured Pick up Value Measured Drop off Value Measurement of Time Delay Characteristic Service M anual R5942B LGPG111 Chapter 9 Page 25 of 52 Expected Time Delay Measured Time Delay Operation Of Output Relays For 51N gt gt Correct Operation Of Output relays N otes Service M anual R5942B LGPG111 Chapter 9 Page 26 of 52 59N Neutral Displacement Measurement Checks Injected Voltage M easured Voltage Characteristic And Operating Time for 59N 1 Ve gt tl Measurement of Ve gt Expected Pick up Value M easured Pick up Value M easured Drop off Value M easurement of Time Delay Characteristic Expected O perating Time M easured O perating Time Operation Of Output Relays For 59N 1 Correct Operation Of Output relays Operating Time For 59N 2 t2 t2 reset Expected O perating Time M easured O perating Time Oper
282. ken to clear any system faults The alarm ele ment functions directly on the measured level of negative phase sequence current The negative phase sequence N PS protection provided by the LGPG111 is a true thermal replica with a definite time alarm stage The N PS protection function is provided for applications where a generator synchronous machine is particularly susceptible to rotor thermal damage in the event of the current supplied to the power system becoming unbalanced The degree Service M anual R5942B LG PG111 Chapter 3 Page 43 of 75 of susceptibility will depend on the generator rotor design cylindrical or salient construction methods of forced cooling employed and the presence of any ancillary metallic rotor components The N PS protection function is driven from the general protection CT inputs of the LGPG111 Unlike many traditional forms of negative phase sequence protection the N PS protection in the LGPG111 is accurate over a wide frequency range Traditional forms of protection derive an operating signal from a filter which is designed to give zero output when a pure positive phase sequence input currentis applied and a high output with pure negative phase sequence current The filter will only behave in the required manner at nominal frequency W hen operating away from nominal frequency an unwanted output would be given even when there is no negative phase sequence input quantity Such relays would need to be disa
283. ken when unpacking and installing the products so that none of the parts are damaged or the settings altered and they must only be handled by skilled persons The installation should be clean dry and reasonably free from dust and excessive vibration The site should be well lit to facilitate inspection CAUTION HEAVY AC INPUT MODULES HANDLE WITH CARE Modules that have been removed from their cases should not be left in situations where they are exposed to dust or damp This particularly applies to installations which are being carried out at the same time as construction work Mounting Products are dispatched either individually or as partofa panel rack assembly Modules should remain protected by their metal case during assembly into a panel or rack The design of the relay is such that the fixing holes are accessible without removal of the cover Dimensions fixing details and cut out sizes for the cases are shown in the case outline drawing GM 0008 in chapter 11 W hen installation is complete the relay must be setup and commissioned as de scribed in chapter 8 Rack Mounting The rack mounting version of the relay is supplied in a case designed for mounting in standard 19 inch 483mm racks Panel mounting The panel mounting version of the relay can be supplied for either flush or semi projecting panel mounting Panels should be vertical to within 5 Dimensions fixing details and cutout sizes for the cases are shown i
284. ks for 60 VB Prot If necessary change the scheme logic input matrix so that only the 60 VB Prot will cause the output relays to operate Inject 0 8xVs gt Volts into the V comparison input terminals B21 B22 Slowly increase the voltage until the relay operates Record the pick up value Check the yellow Alarm LED flashes and the ALARM Protection 60 VB Prot appears on the display ignore other alarms W ith the relay operated slowly decrease the voltage injected until the relay resets Record the drop off value Repeat the test for the V comparison input terminals B23 B2 4 Pick up voltage Vs with a 5 tolerance Drop off voltage 0 95xVs with a 5 tolerance Characteristic checks for 60 VB C omp Enable the 60 Voltage Balance protection only If necessary change the scheme logic input matrix so that only the 60 VB Comp will cause the output relays to operate Inject 0 8xVs gt Volts into the V protection input terminals B25 B26 Slowly increase the voltage until the relay operates Record the pick up value Check the yellow Alarm LED flashes and the ALARM Protection 60 VB Comp appears on the display ignore other alarms W ith the relay operated slowly decrease the voltage injected until the relay resets Record the drop off value Service M anual R5942C LG PG111 Chapter 8 7 14 4 Page 57 of 66 Repeat the test for the V protection input terminals B27 B28 Pick up voltage Vs with a 5 tole
285. lain tripping logic LO blocking logic L1 interlocking logic 12 and a combination of interlocking and blocking logic L3 in the scheme logic Word LO Operation of the 87G Differential will operate output relays R15 and R1 This is an independent operation Word L1 O peration of the 51V Voltage Dependent O vercurrent will operate output relays R15 and R2 if the 60 Voltage Balance for fuse failure does not operate This is a block ing operation as indicated by the prefixed R15 and R2 operation op of 51V NO op of 60 Word L2 Operations of the 51N gt gt Stator Earth Fault high set element and the 67N Sensitive Directional Earth fault will operate relay R15 This is an interlocking operation since both must operate R15 operation op of 51N gt gt 0p of 67N Word L3 Operation of the 40 Field Failure and the 32LLow Forward Power at the same time will operate output relays R15 and R4 but only if the 60 Voltage Balance has not operated This is a combined interlocking and blocking operation R15 and R4 operation op of 40 op of 32L NO op of 60 Interlocking logic exists when there is more than one 1 flag in a particular input AND matrix word of the scheme logic However 1 s associated with negated inputs are used for blocking N egated inputs have names beginning with a minus Figure 3 illustrates the scheme logic of Figure 2 in a more classical form of relay ladder logic Figure 3 The
286. lay 15 R5942B Chapter 6 Page 29 of 91 Bits 1 to 15 are the fifteen scheme configurable outputs and their names can be changed in the input output labels section Bit 0 the relay inopera tive alarms normally energised to indicate thatthe LG PG 111 is functioning correctly However its bit indication is inverted so that it normally indicates asa 0 a 1 meaning that the relay is inoperative Service M anual R5942B LG PG111 Chapter 6 Page 30 of 91 7 3 Auxiliary Functions Item Front Panel Remote Access l 2 0 AUXILIARY Auxiliary Functions FUNCTIONS 2 1 Date 1994 Aug 16 16 Aug 1994 10 49 50 769 Time 10 49 50 2 2 Logic I P Status Logic Input Status 00000000000000 00000000000000 2 3 Relay O P Status Relay Output Status 0000000000000000 0000000000000000 o 2 4 Protection Protection Status Status gt 00000000000000000010 2 5 Relay Alarms Relay Alarms Not Present ot Present 12 6 Scheme Output Scheme Output Enabled Enabled 2 7 Clear Event Clear Event Records No Records 2 8 Prine Stopped Print Stopped 2 9 Second Setting Second Setting Group Disabled Group Disabled 12 10 Select Setting Select Setting Group Menu Group Menu o 2 11 Active Setting Active Setting Group 1 Group 1 2 12 Remote Setting Remote Setting Enabled Enabled 2 13 In
287. le The latter module contains the first six dedicated inputs and the former module contains the remaining eight scheme definable inputs Using the logic input status cell in the Auxiliary Functions section of the menu the status of all 14 inputs can be ascertained Manually energising each input should cause the corresponding bit flag in the status cell to change from 0 to 1 and vice versa Care should be taken to avoid inadvertent operation of external plant isolate Service M anual R5942C LG PG111 Chapter 7 3 6 3 7 Page 9 of 14 plant connections to the logic inputs Analogue input checks The analogue input circuitry includes a self check which allows the operation of the multiplexers sample and hold analogue to digital converter to be constantly monitored Failures in this circuitry will automatically be reported and the relay will attempt to recover from this fault by forcing a watchdog reset once only If the attempt fails the protection will be disabled and the relay is out of service Failures in the internal transformers and anti aliasing filters can be determined by comparison of the measurements in the menu with known injected quantities Care should be taken to ensure that apparent failures are due to the analogue module and not due to external wiring and transducer failures The analogue input module also contains a non volatile EEPRO M which stores the module s calibration data This data is read during a reset
288. lead to rapid localised heating which may threaten the integrity of electrical insulation or increase the ageing of insulation etc The common causes of plant over fluxing at generating stations are during under frequency operation of plant prior to synchronising and over voltage following sudden load rejection During slow run up of a generator the level of excitation must be controlled to limit the terminal voltage so that over fluxing does not occur If excitation is commenced too early during run up and the automatic voltage regulator is enabled to excite the machine to try and attain nominal voltage before nominal speed is reached over fluxing of plant may occur Severe over fluxing could result in operation of some designs of transformer differential protection which would be beneficial for a sustained condition However such tripping cannot be relied upon since some protective relays are designed to try and prevent tripping due to transient over fluxing that would not pose a threat to a transformer Following significant load rejection a generator terminal over voltage will transiently exist until the automatic voltage regulator is able to reduce excitation sufficiently An over voltage condition will occur immediately following load rejection before the machine accelerates to increase frequency and reduce over fluxing The governor and prime mover response might also be faster than old style regulator response times so that the com
289. lished prior to synchronisation as long as no other protection element has operated If the protected generator is notin service butis accidentally energised fast tripping by undelayed overcurrent protection function 51V or by undelayed field failure protection function should occur Even if the LGPG111 sees a voltage above 99V when the protected machine is accidentally energised the group 2 settings will be maintained for at least 1s and for as long as any subsequent protection function operation is maintained e g 51V or 40 Service M anual R5942B LG PG111 Chapter 3 3 2 Page 61 of 75 Breaker flashover protection Prior to generator synchronisation or just following generator tripping where the protected generator could be slipping with respect to a power system itis possible to establish at least twice rated phase neutral voltage across the generator circuit breaker An even higher voltage might briefly be established just after generator tripping for prime mover failure where the pre ailure level of excitation might be maintained until AVR action takes place W hilst generator circuit breakers must be designed to handle such situations the probability of breaker interrupter breakdown or breakdown of contaminated open terminal switch gear insulators is increased and such failures have occurred This mode of breaker failure is most likely to occur on one phase initially and could be detected by a neutral current measuring ele
290. low the analogue inputs and their associated connections to be checked The status of the logic inputs is displayed in the System Data and the Auxiliary Functions Sections of the menu This allows tests to be carried out on the individual inputs and associated plant The relay can display the operation of each protection function as a percentage of the final trip time in the Protection O peration Summary Section of the menu The protection will trip when the target count reaches 100 This allows the pick up progress and operation of any protection function to be checked A Scheme O utput setting in the Auxiliary Functions menu Section is available to inhibit the scheme from operating the output contacts W hen the setting is set to inhibited the out of service LED on the front panel is illuminated although all the other relay functions including the protection and the recording are carried out normally It is then possible to carry out secondary injection tests without any risk of nuisance tripping W hilst in this mode itis also possible to test individual output contacts as explained later Besides these facilities the Test Functions Section of the menu provides further test options 1 Lamp Test to test the four indicating LED s 2 Relay Test to test the individual relay output contacts 3 Scheme Setting check to check for half programmed logic words in the scheme logic 4 Scheme Logic Test to verify the logic of the scheme s
291. ls B27 B28 Record and check the frequency injected and the value measured by the relay allowing 0 5 Hz tolerance Characteristic and operating time The LG PG111 s under frequency protection consists of two independent elements 81U 1 amp 81U 2 If both are used in the scheme logic then the following tests should be repeated for both elements Record the under frequency settings for the 81U 1 F1 lt and tl Enable the 81U 1 under frequency protection only If necessary change the scheme logic input matrix so that only the 81U 1 will cause the output relays to operate Measurement of F1l lt with a variable frequency supply If a variable frequency voltage source is available carry out the tests as follows Inject rated voltage with frequency above the F1 lt setting into the V input terminals B27 B28 Vary the frequency to check the relay s pick up and drop off values Stop injecting and reset all alarms Service M LG PG111 anual R5942C Chapter 8 Page 50 of 66 Pick up frequency F1l lt with a 0 5Hz tolerance Drop off frequency Fl lt 0 2 Hz witha 0 5Hz tolerance Measurement of operating time with a variable frequency supply Arrange the variable frequency supply to step change the frequency from above Fl lt to less than 0 8 x F1 lt to obtain the relay s operating time Alternatively this can be accomplished by changing the voltage connection to the relay from a system supply to the variable freque
292. lt clearance especially when there is a weak high reactance transmission link between the generator and the rest of the power system KCEG gt Foward start KCEG directional relays are required where backfeed from another power system source is possible otherwise non directional KCGG relays could be used Figure 25 Interlocked voltage dependant overcurrent protection function The process of pole slipping following excitation failure is discussed in Section 2 9 The LGPG111 impedance ype field failure protection function should respond to such situations to give a time delayed trip The electrical mechanical power torque oscillations following excitation failure would be relatively gentle If pole slipping occurs with maximum excitation generator emf gt 2 0 p u the power torque oscillations and power system voltage fluctuations following loss of stability would be much more severe There may be arequirement to confirm that protection is provided to trip the generator under such circumstances to prevent plant damage or remove the disturbance to the power system Service M anual R5942B LG PG111 Chapter 3 3 5 1 Page 65 of 75 W ith large utility baseload generators the requirement for pole slipping protection will be dependent on the transmission system reactance In the case of generators connected to a dense interconnected system pole slipping protection may notbe required In the case of remote generation and a w
293. lt in unwanted alarms during normal operation Field failure protection function 40 Summary e Monitors the generators terminal impedance in order to detect failures in the excitation system e Uses a circular offset mho impedance characteristic e The diameter of the impedance characteristic is based on the direct synchro nous reactance of the generator e The offset of the impedance characteristic based on the direct axis transient reactance of the generator e An associated definite time delay prevents operation of the protection during stable power swings e Can be interlocked with the under voltage protection element using the internal scheme logic of the LG PG to prevent operation during power swings e A delay on drop off timer can be used to detect cyclic operation of the field failure protection This could result during pole slipping using the field failure element to detect pole slipping as discussed in Section 3 5 This protection function measures the impedance at the terminals of a generator that is run in parallel with another source to detect failure of the generator excitation The current used for single phase impedance measurement is obtained from the general protection CT inputs and the voltage is obtained from the main VT inputs This protection function is provided with an adjustable offset circular impedance characteristic see Figure 17 an adjustable tripping delay timer t and an adjustable measu
294. lt record checks Use the front panel keys to navigate to the menu section View Records and ensure that the records match the injected faults carried out above O peration of output relays Inject sufficient current into the relay to operate the 51V Check the operation of the LG PG111 s output relays against the scheme logic settings Record the output relays operated 46 Negative phase sequence The negative phase sequence function is for the detection of unbalanced load conditions Under such conditions second harmonic frequency eddy currents are induced into the rotor which can cause rapid overheating The function has a thermal replica characteristic which can be set to closely match the negative phase sequence withstand characteristic of the machine In order to take into account the heating effect of the standing negative phase sequence current under normal healthy working conditions pre heating of the machine is simulated The operating time t gt gt of the trip element follows a time current characteristic equation as given by the expression 2 t gt gt K 5 jog qi h gt gt h Where gt gt negative phase current threshold Service M anual R5942C LG PG 111 7 9 1 T9323 Chapter 8 Page 44 of 66 K constant proportion to the thermal capacity of the generator rotor negative phase sequence current present The characteristic approximates to the t K I characteristic when the
295. m Current I Service M LG PG111 4 3 4 3 1 anual R5942B Chapter 6 Page 10 of 91 Pa 43 02 W ol Active amp Reactive ye e Phase Angle Of l W ith 8a 5 0 deg Respect To Va Frequency e System Frequency ee i Sat 1994 Jan 01 e Date and Time seen e Active Setting Group Sane CECUD Active e All default display Cycles through the above 7 measurement displays M easurements at 5s intervals The description model number and plant reference displays correspond to their respective cells in the System Data Section of the menu There are three over ride warning displays e Alarm Prompt ATARM Mimics operation of alarm LED e Real time calendar clock NOT SET UP DATE AND TIME uninitialised e Password protected settings unlocked Local Settings Local refers to the front Unlocked panel interface as opposed to the remote communications interface The priority for the selection of the default displays is shown in the Table below Priority Default Display 1 Highest Alarm prompt 2 Real time calendar clock uninitialised 3 Local front panel settings unlocked 4 Lowest Primary default display as selected by user Table 1 Default display priorities Modes of operation The front panel interface provides three modes of operation e Alarm scan e Menu scan and e Menu browse Alarm scan The alarm s
296. m may be deemed acceptable for non urgent protection trips e g stator earth fault protection for an indirectly connected generator For urgent trips by instantaneous electrical protection e g stator winding current differential protection any potentially delaying interlock should not be imposed W ith the low probability of urgent trips the risk of over speed and possible consequences must be accepted Service M anual R5942B LG PG111 Chapter 3 2 8 Page 42 of 75 W hen required the setting of the LGPG111 low forward power protection function should be less than 50 of the power level that could result in a dangerous over speed transient without electrical loading W ith a large generator even a very small percentage of rated power could quickly accelerate an unloaded machine to a dangerous speed A typical under power setting requirement would be 0 5 of rated power The calculation to determine the required setting of the LGPG111 threshold P lt in single phase secondary W atts would be similar to that quoted in Section 2 7 1 for the reverse power protection function threshold P gt The time delay associated with the low forward power protection function t could be set to zero However some delay is desirable so that permission for a non urgent electrical trip is not given in the event of power fluctuations arising from sudden steam valve throttle closure A typical time delay for this reason is 2s An adju
297. m analysis The LGPG111 consists of seven removable modules In the unlikely event of component failure the following fault finding information should allow the identification of the failed module There are no serviceable parts within any module The procedure for repair is to identify the faulty module and replace it The faulty module should be returned for repair and calibration with as much information regarding the fault as possible This documentation assumes you are conversant with the operating instructions and hardware arrangement of the relay Warning 1 The relay must be de energised before the hinged front panel is opened and any bus connections removed Failure to comply with this instruction may result in damage to the electronic circuits of the modules or corruption of non volatile memory 2 Modules must be removed from the case with a proper module extraction tool It is especially important that the analogue and status input module is handled with care the front PCB should not be forcibly handled during extraction or insertion Note that this module is heavy 3 With the hinged front panel open electrostatic discharge precau tions must be observed Fault finding procedure Problems which arise in the LGPG111 as a result of a faulty module will usually result in one of the following occurring 1 The relay will fail to power up or initialise correctly 2 The self monitoring will lockout the relay if a failure
298. ment If the generator is directly connected to the power system the additional current operated stator earth fault protection function element le gt gt could be applied as an instantaneous element to quickly detect the flashover This additional element could be enabled and arranged to operate an output contact when an assigned logic input is energised via a normally closed circuit breaker auxiliary contact which indicates to the LG PG 111 that the circuit breaker is supposed to be open This arrangement could be setup using the LG PG111 s flexible scheme logic see Figure 23 W hen a generator is connected to the power system via a step up transformer with only an HV synchronising breaker it would be necessary to enable an instantaneous element of the HV standby earth fault protection If this protection is being provided by a KCGG110 relay for instance one of the additional protection elements of this relay lo lt or lo gt gt could be set to operate without delay This protection element would be enabled when the circuit is open the closing of a normally open generator breaker auxiliary contact can be used to block this specific relay element see Fig2 4 t gt 0s De select Group 2 Input 7 RL13 Connect externally to Logic inputs 3 amp 4 Select Group 2 59 Connect externally RL12 to Logic inputs 7 V gt 99V t gt 1s De select Group 2 V gt gt 99V t gt gt I1s SCHEME LOGIC GROUP 2 SETTING Figure 22 De
299. mental Frequency 1st order Low Pass Filter Combined Frequency Response 100 200 300 400 500 Frequency Hz a Fourier filter and the 1st order low pass filter 2nd Order Low pass Filter Combined Frequency Response b Fourier Filter and the 2nd order low pass filter for the transactor inputs only Figure 6 Composite frequency response of the Fourier filter and the anti aliasing filters Service M anual R5942B LG PG111 2 5 2 6 2 7 Chapter 4 Page 14 of 50 Magnitude approximation The Fourier sine and cosine components of a signal can be converted into rms magni tude by evaluating a 1 2 1 2 calculation A direct implementation of this would be difficult to realise using an integer microprocessor due to the squared root function Therefore a linear approximation technique is used as follows Let u max ls Ic v min Is Ic then for u gt 4v I 0 9950u 0 1225v for4v gt u gt 2v I 0 9398u 0 3476v for6v2 3u gt 4v I 0 8518u 0 5264v for 4v 2 3u I 0 7559u 0 6560v This linear approximation technique introduces an error of 0 5 to 0 25 in the calculation Phase angle calculation Using the Fourier components itis possible to calculate the phase angle of the vector in the complex plane by implementing the trigonometric tan Ic Is function Again direct implementation is difficult Instead a look up table technique is used to determine the angle A ta
300. mmunications language The remote user interface is accessed by a PC installed with suitable Courier based access software connected to one of the three serial ports Courier based access software polls all relays connected to its system and allows a user to access information in each relay connected by extracting the contents of the relay s database ALSTOM Protection amp Control Limited can supply suitable remote access software for use on a standard IBM compatible personal computer Alternatively a specifically programmed third party data acquisition device can be connected to collect data for data logging equipment e g SCADA Service M anual LG PG111 R5942B Chapter 6 Page 18 of 91 Typical features of a remote access system are To provide the means to examine the relay s menu The remote system can presenta list of the available sections and then by selecting a section its contents can be displayed In both cases the remote system can usually display an entire page or window of the section titles or the section contents at once or atleast a scrollable page which provides a major advantage over the small display on the front panel Remote measurements The measurement values which can be displayed on the front of the relay can be polled regularly and stored to disk or graphically displayed on the screen of the PC Automatic extraction of event and fault records A sequential list of events can be captured automat
301. mplement the current operated protection function in the case of distribution transformer earthing as Service M anual R5942B LG PG 111 2 5 Chapter 3 Page 26 of 75 described in Section 2 3 2 The first stage protection 59N 1 time delay should be set with the considerations that applied to setting the main current operated protection element le gt as discussed in Section 2 3 2 Sensitive directional earth fault protection function 67N Summary e Applied where two or more generators are connected directly to a common busbar e The operating currentis obtained from the residual connection of the line side CTs e A sensitive operating current setting of 5 of the maximum earth fault level should be applied e Where the required sensitivity cannot be obtained from the residual connection of CTs a dedicated core balance CT can be used e Either current or voltage polarised e The stator earth fault input provides the current polarising signal e The neutral voltage displacement input provides the voltage polarising input e W hen voltage polarised the polarising threshold should be setto give an operating threshold equivalent to the current setting e W hen current polarised the polarising threshold should be just below the operating current setting e W hen combined with the neutral displacement protection the inadvertent opera tion of earth fault protection during transient CT saturation can be achieved
302. n and reset of the main trip timer t and consequent failure to trip an adjustable delay on measuring element reset tDO is provided This delay would need to be set longer than the period for which the reverse power could fall below the power setting P gt This setting needs to be taken into account when setting the main trip time delay t as discussed above It should also be noted that a delay on reset in excess of half the period of any system power swings could result in operation of the reverse power protection during swings In general the reset delay tDO should be set to zero In some applications the reverse power protection function should be disabled during Service M anual R5942B LG PG 111 2 1 2 Chapter 3 Page 40 of 75 certain modes of protected machine operation O ne example of such a situation is where during dry seasons a synchronous machine is decoupled from its hydraulic prime mover and operated as a synchronous compensator for power system VAR control O ne way of disabling the reverse power protection function would be to switch from the normal group of LG PG 111 settings where this protection function is enabled to the second group of settings where this protection function has not been enabled Alternatively a spare logic input could be assigned through the relay scheme logic matrix to actas a blocking input for the reverse power protection function It should be noted that the reverse power pr
303. n is enabled ata time protection interlocking logic in the scheme logic must be removed to allow each individual protection function to operate its output contact Interlocking logic exists when there is more than one 1 flag in a particular input AN D matrix word of the scheme logic However 1 s associated with negated inputs can be discounted as these are used for blocking N egated inputs have names beginning with a minus To disable Service M anual R5942C LG PG111 Chapter 8 Page 13 of 66 interlocking change the 1 to 0 for the interlocking element Figure 1 illustrates the various types of logical arrangements which the LG PG111 s scheme logic is capable of providing Word LO Operation of the 87G Differential will operate output relays R15 and R1 This is an independent operation and can be tested without modification Word L1 O peration of the 51V Voltage Dependent O vercurrent will operate output relays R15 and R2 if the 60 Voltage Balance for fuse failure does not operate This is a block ing operation as indicated by the prefixed W ith the voltage balance function disabled the voltage dependent overcurrent can be tested without modification to the scheme Word L Operations of the 51N gt gt Stator Earth Fault high set element and the 67N Sensitive Directional Earth fault will operate relays R15 and R3 This is an interlocking opera tion To test the stator earth fault high set the i
304. n status A 20 bit binary flag representation of the protection function outputs These outputs combined with the logic inputs are fed into the scheme logic The Front Panel display of the bit flag values is obtained by pressing the arrow key The bits are summarised in Table 10 Front Panel N ame Remote Access N ame 60 VB Comp 60 Voltage Balance Comp 67N Sensitive Directional EF 59N 2 Neutral Displacement 5 6 59N 1 D 59N 1 Neutral Displacement 7 51N gt gt SEF 51N gt gt Stator Earth Fault 8 51N gt SEF 51N gt Stator Earth Fault 9 46 gt gt NPS 46 gt gt NPS Trip 10 46 gt NPS 46 gt NPS Alarm 11 59 OV 59 Over Voltage 12 27 UV 27 Under Voltage 13 810 2 UF 810 2 Under Frequency 14 810 1 UF 810 1 Under Frequency 15 810 OF 810 Over Frequency 16 321 LFP 32L Low Forward Power 17 32R RP 32R Reverse Power 18 51v OC 51v Overcurrent 19 87G Gen Diff 87G Generator Differential Table 10 Bit flag assignment read right to left of the protection functions Service M LG PG111 2 5 anual R5942B Chapter 6 Page 32 of 91 Note Bits 1 amp 2 are complements of each other For healthy voltage input bit 1 will be set since itis the complementary output from the voltage balance func tion W hen there is a voltage balance fault bit2 will be setand bit 1 cleared Relay Alarms
305. n the relevant case outline drawing The flush mounted relay is inserted from the front into the panel cutout and secured by means of nuts and bolts through holes in the upper and lower flanges in the relay and corresponding holes in the panel The semi projecting version of the relay is fitted with an extending collar and is fixed Service M anual R5942A LG PG111 Chapter 2 Page 6 of 6 in a similar manner to the flush mounted version 3 2 Auxiliary power supplies The LGPG 111 is designed to be powered from a DC auxiliary power supply within the limits of its Vx1 rated specification Equally the status inputs are designed to be energised from a DC auxiliary power supply within the limits of its Vx2 rated specification The operative ranges for each nominal rating value of Vx1 and Vx2 is summarised in the table below The relay can withstand some AC ripple on its DC auxiliary supplies however the peak value of the auxiliary supply should not exceed the maximum withstand value Do not energise the relay from a supply with the batteries disconnected and the system run from the charger alone The LGPG111 is fitted with transient suppression circuits which are designed to protect it from potential damage by intermittent spikes of short duration Nominal Rating of 24 27V 30 34V 48 54V 110 125V 220 250V Vx1 and Vx2 Operative Range 19 2 32 4 V 24 40 8 V 38 4 64 8 V 88 150 V 176 300 V Maximum W ithstand 45 9 V 72 9 V 4 S
306. nable group 2 relay settings for dead machine protection as discussed in Section 3 1 Under voltage protection can be used to detect abnormal operating conditions or an uncleared power system fault that may not have been detected by other generator protection For an isolated generator or for an isolated set of generators especially in the case of standby generating plant a prolonged under voltage condition could arise for a Service M anual R5942B LG PG111 Chapter 3 Page 52 of 75 number of reasons O ne reason would be some failure of automatic voltage regulation AVR equipment If such a condition persists automatic generator tripping should be initiated to prevent possible damage to system loads Another reason could be thata fault exists somewhere on the power system that has not been cleared by other means In the case of generators feeding an industrial system which is normally fed from a public power supply system overcurrent protection settings would have to be above maximum levels of system load current with the normal supply available If the public supply fails the local generation would be left feeding the entire system W here the local generation is unable to meet the entire system load there would be a provision for the automatic shedding of non essential loads If a fault subsequently occurred on the system the relatively low fault current contribution of the local generation and its decrement with time may result in th
307. nclude this cell System frequency Specifies the nominal system frequency which the LGPG111 is monitoring Can be set to 50Hz 55Hz or 60Hz The setting determines the default tracking frequency when the relay has no input signals The setting has no effect on the frequency tracking capability of the LGPG111 Communications level A non settable cell which indicates the capability of the remote communications interface to a remote system The LG PG 111 implements level 1 Courier communications Relay address The address of the LGPG 111 on a remote communications network Settable between 0 and 255 A value of 255 effectively removes the relay from direct addressing over the network and a value of 0 is used as a transition address by a remote system a transition address is automatically changed by the remote system to a spare address on the network The remote access setting Service M anual LG PG111 1 9 R5942B Chapter 6 Page 28 of 91 transfer does not include this cell This cell is duplicated in the Remote Communications Section Active setting group A non settable cell reflecting the currently active setting group Used by the remote system to ascertain the LGPG111 s current setting group selection This cell is duplicated in the Auxiliary Functions Section where it may be changed Software reference 1 The identity of the software in the main processor Software reference 2 The identity of the software in th
308. ncy supply set at 0 8xF1 lt The single pole quad throw switch can be used for this purpose Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check the ALARM Protection 81U 1 UF appears on the display ignore other alarms Reset all alarms Record the operating time O perating time tl with a 5 tolerance 10 to 60mS If a variable frequency voltage source is not available carry out the tests as follows Measurement of Fl lt without a variable frequency supply Inject rated voltage with rated frequency into the V input terminals B27 B28 Increase the setting Fl lt in steps of 0 1 Hz until the relay operates and then record the setting Stop injecting and reset all alarms F1 lt setting injected frequency with a 0 5 Hz tolerance W ith the relay operated decrease the setting F1 lt to check when the output contacts reset Record the setting which causes the relay to reset F1 lt setting injected frequency 0 2Hz with a 0 5 Hz tolerance Measurement of operating time without a variable frequency supply W ith the F1 lt setting set to a value higher than the rated frequency energize the 27 and 81U Inhibit logic input with a voltage equal to relay s Vx 2 rating Inject rated voltage with rated frequency into the V input terminals B27 B28 Arrange to de energize the 27 and 81U Inhibit logic input and start a timer at the same time to obtain the relay s o
309. nd dialling the external number A common problem with PBX s is phase noise This is not noticeable in speech but will cause problems with frequency and phase encoded digital transmission Phase noise can be the source of intermittent communications errors but it can also be severe enough to stop any form of successful communications In this case the solution is to install a direct dial line or even a dedicated private line There are also sophisticated modems available which have phase noise cancel lation features that may be able to overcome these difficulties Check the configuration of the remote access software being used see relevant documentation M ost of the previous points will also relate to the remote access system Service M anual R5942C LG PG 111 Chapter 7 Page 14 of 14 4 11 2 Communications fails Check the following 1 The integrity of the communications link 2 The LGPG111 is powered up 3 The communications hardware is still functioning check for a communications hardware failure alarm Consider fault finding the communications isolation card and communications hardware 3 The communications settings have not been changed in the relay or the remote access system rendering them incompatible 4 Check modems interface boxes etc are powered up and that settings have not been changed 5 Check for modem communication problems noisy telephone line line discon nected etc 4 11 3 General 1 T
310. nd record being reduced by the proximity of the second trigger to the end of the first record The two records are continuous and there is no loss of information Inaccurate measurements May also manifest as inaccurate pickup levels during injection testing 1 For the LGPG111 to make accurate measurements it must be frequency track ing The relay can only frequency track on one of three channels namely Vp V and which it automatically selects depending upon the presence of suffi cient signals Therefore injecting on any other channel will not provide the relay with a frequency source to track and the relay will assume its default tracking frequency It is recommended that all checks on measurement and protection accuracy are made with the frequency track engaged This can be accomplished by series connecting with current inputs under test and parallel connecting V or V with voltage inputs under test The last cell of the M easure ments 2 section of the menu indicates which input is driving the frequency Service M anual R5942C LG PG 111 Chapter 7 Page 12 of 14 tracking Since the frequency tracking is based ona single phase measurement itis assumed that all other inputs are of the same frequency The relay has lostits calibration data This will be indicated by none resettable alarm message on the front panel The analogue and status input module will need to be replaced or re calibrated 4 9 Problems with printing 1
311. nection for the rear mounted RS232 serial connector The signal ground of RS232 connection is not connected to the OV of the relay This ensures that no earth loop currents can flow between the relay and other connected equipments If itis required to connect the RS232 signal ground to the OV of the relay then a 150Q resistor can be fitted onto the PCB for R26 This modification will result in there being no isolation between the relay and the RS232 connection Itis recommended that any modifications are carried out by ALSTOM T amp D Protection amp Control Limited 5 4 1 10 Recommended cable A standard PC serial port interface cable should be used It is essential that the cable screen be earthed at one end to ensure adequate screening The connectors should be screw locked at each end Reference should also be made to the PC or modem user manual for the exact connection requirements 5 4 1 11 Cable length 3Pins on The maximum recommended cable length between IEC870 communication ports is 15m or 2500pF total cable capacitance the 25 way connector that are not listed are not connected Service M anual R5942B LG PG 111 Chapter 5 Page 14 of 23 5 4 1 12 Data rates 5 5 5 6 The maximum data rate available on the LGPG111 is 19600 bits per second Status input Five versions are available covering the following DC supply voltages Eight optically isolated logic status inputs are provided which are rated at the auxil
312. nf If the phase angle of the vector is calculated once every cycle i e 12 fmo the result of the calculation should be the same from one cycle to the next In other words the rotating vector is expected to return to its original position after one cycle Any angle deviation will indicate that there is a mismatch in the sampling frequency and the system frequency Service M anual R5942B LG PG111 Chapter 4 2 8 Page 15 of 50 Let Ad Omeasured 0 expected Then it can be shown that f Ad f mp AD Dk W here t is time interval over which Ag is measured For angle calculations performed once every cycle t equals 12 f samp There are two cases of mismatch in the two frequencies on the complex plane as shown in Figure 7 If Ad is positive it indicates that the system frequency has increased If Ad is negative it indicates that the system frequency has decreased The change in system frequency is proportional to the Ad calculated After the frequency measurement has been calculated the sampling clock is then adjusted to minimise Ao Ad gt 0 system frequency increasing Ad lt 0 system frequency decreasing Figure 7 Angle deviation caused by frequency mismatch during frequency tracking Using this method the range of frequencies which the relay can track is limited from Y fom 12 to fial 12 For example if the frequency setting of the relay is setat 50Hz the theoretical tracking range is from 25Hz to 7
313. ng modules do not have any jumper links Power supply module GM0026 GM0097 Isolation module GM0100 The parallel printer connection is a sub set of the IBM PC printer port An IBM printer cable can be used by disconnecting the Do not connect lines Service M anual R5942B LG PG 111 Chapter 5 Page 20 of 23 6 1 Relay output module GM0032 6 1 1 Address decode Two links are required to select the correct address decode for this module a coarse and fine address selection See Figure 2 for the relay output module link positions Coarse JM2 No link Fine JM1 Module atpositionNo 2 link 1 16 Module at position No 3 Link 2 15 ZHO929__ 6 4 JM2 4 333 5 1 8 222 2 M1 16 9 Figure 2 Relay output module link positions 6 2 Microcomputer amp serial communications module GM0099 6 2 1 Microprocessor board The microprocessor board has several options which must be selected with links Four memory banks must be configured the watchdog enabled interrupt amp DM A configured and the internal RS232 test port setup See Figure 3 for the microcomputer module link positions 6 2 1 1 Memory selection JM1 lnk 12 45 79 jM2 Unk 12 44 78 jM3 Unk 12 45 79 jM4 lnk 12 O e a Service M anual R5942B LG PG111 Chapter 5 6 2 1 2 6 2 1 3 6 2 1 4 6 3 6 3 1 Page 21 of 23 W atchdog Timer J
314. ng test results chapter 9 W ith the analogue input module removed from the case check that the shorting switches between the terminals listed below are closed This can be done either with a continuity check or by injecting rated current In through the shorting contacts Both methods will require the external CT s to be isolated from the relay Earthing A5 and A6 A7 and A8 A9 and A10 A11 and A12 A13 and A14 A15 and A16 A17 andA18 A19 and A20 A21 and A22 A23 and A24 A25 and A26 A27 and A28 Table 1 Terminals fitted with internal shorting switches Ensure the case earthing terminal above relay terminal block H is used to connect the relay to the local earth bar Main current transformers Do not open the secondary circuit of a live CT since the high voltage produced may be lethal to personnel and could damage insulation Insulation Insulation tests can be done if required but are not necessary for the LGPG111 s commissioning The insulation of the relay and its associated wiring may be tested between 1 All electrically isolated circuits and 2 All circuits to earth An electronic or brushless tester having a voltage not exceeding 1000V DC should be used Accessible terminals of the same circuit should first be connected together Deliberate circuit earthing links removed for the tests must be subsequently replaced The outgoing terminal allocation for the relay is shown in the drawing
315. ng the frequency spectra of the input signal is achieved by using anti aliasing filters W ith the exception of the transactor inputs the relay s CT s and VT s have a constant frequency response within the operating frequency range of 5Hz to 70Hz The anti aliasing filter used for all these input signals is a firstorder passive low pass filter with a cutoff frequency at 132Hz The gain frequency response of a transactor is different from a CT and increases with frequency To compensate for this the anti aliasing filter is designed to attenuate increasingly the transactor s output with respect to frequency The combined effect produces a reasonably constant gain response which allows the differential function to work accurately over the frequency range from 25Hz to 70Hz The actual filter used is a 2 pole active low pass filter with a cutoff frequency at55 Hz Data sampling All the input signals are sampled ata rate of 12 samples per cycle This sampling rate provides a theoretical bandwidth of 6 times the fundamental This is adequate for the extraction of the fundamental components and provides a good bandwidth coverage for the disturbance waveform recording function The 17 input signals are sampled sequentially Three multiplexers are used to multiplex the sampled signals to the signal conversion circuitry Additionally two reference DC levels 5V and OV are available to each multiplexer These act as voltage references for
316. ng time t gt gt setting with a 5 tolerance 10 to 40mS O peration of output relays Repeat the previous injection to operate the 59 Over Voltage element Check the operation of the output relays against the scheme logic settings Record the output relays operated Restore the original Scheme Logic settings if changed 60 Voltage balance The 60 Voltage Balance element can detect the failure of a fuse in either the protection VT s or the comparison VT s The voltage balance compares measurements Service M anual R5942C LG PG 111 7 14 1 7 14 2 7 14 3 Chapter 8 Page 56 of 66 of V and V from the protection VT s with the corresponding measurements from the comparison VT s If a difference of greater than the setting is detected the voltage balance element will operate This function can be set to block possible incorrect operation of those protection functions whose performance may be affected by the apparent loss of voltage such as when a VT fuse blows Enable the 60 Voltage Balance protection only Record the voltage balance setting Vs M easurement checks Inject rated voltage into the protection VT s the V input terminals B25 B26 and the V lt input terminals B27 B28 Record and check the voltage injected and the values measured by the relay allowing 3 tolerance Repeat for the comparison VT s the V input terminals B21 B22 and the V input terminals B23 B24 Characteristic chec
317. ng types and levels of mechanical protection are necessary such as vibration detection lubricant and coolant monitoring etc The action required following response of an element of electrical or mechanical protection is often categorised as follows Urgent shutdown N on urgent shutdown Alarm only Service M anual R5942B LG PG111 Chapter 3 1 3 Page 7 of 75 An urgent shutdown would be required for example if a phase to phase fault occurred within the generator electrical connections A non urgent shutdown might be sequential where the prime mover may be shutdown prior to electrically unloading the generator in order to avoid over speed in the case of a steam turbine A non urgent shutdown may be initiated in the case of continued unbalanced loading In the event of unbalanced loading itis desirable that an alarm should be given before shutdown becomes necessary in order to allow for possible operator intervention to remedy the situation For urgent tripping it may be desirable to electrically maintain the shutdown condition with latching protection output contacts which would require manual resetting For a non urgent shutdown it may be required that the output contacts reset without intervention so that production of power can be recommenced as soon as possible LGPG111 integrated protection The LGPG111 incorporates the commonly required protection functions for a wide variety of generating plant applications
318. nged with the Tand Lkeys Pecan leecher A Figure 10 Example of the front panel menu browse procedure Entering the password Service M anual R5942B LG PG111 Chapter 6 Page 16 of 91 Default Display M enu Contents Section Contents GENERATOR SYSTEM DATA PROTECTION Date 1994 Jan O1 Time 00 00 03 Logic I P Stat Example i Logic Input Status ree en cae Setting Mode Nera E ee This cell is nota setting however the bits can be examined The and lt arrow keys allow individual bits to be selected The top line indicates the name of the selected bit Bit 0 is always in the bottom right of the display and in this example bit 13 is leftmost N ote that bits 6 to 13 of the Logic Inputs are scheme configurable with definable names Input 13 Input 12 Input 11 00000000000000 00000000000000 00000000000000 Press RESET to quit this mode The above procedure is slightly modified for binary flag cells with more than 16 bits For example the protection function status cell Default Display M enu Contents Section Contents GENERATOR SYSTEM DATA PROTECTION Date 1994 Jan 01 Time 00 00 03 a Logic I P Stat Example ii Protection Function Status SER Re cits Here because the 20 bit status information will not fit on the bottom line of the display an extra display is introduced Relay O P Statu
319. nput matrix is made up of a series of 32 bit input words and similarly the output matrix is made up ofa series of 15 bit output words A connection is made by changing a particular bit from 0 to 1 Various facilities are built into the relay to make the setting up of the scheme logic easy and secure In setting mode when an interconnection bitis selected a prompt identifies its function This ensures the correct selection of an input or output bit where a connection is to be made A scheme test facility is available this allows the scheme s response to input scenarios to be checked The facility can be exercised at any time without affecting the protection functions Also the LGPG111 parallel printer connection can be used to print the scheme settings in a matrix format which allows easy comparison with the intended set up The design of the scheme logic provides sufficient flexibility for different generator schemes W ith the OR functions the selection of protection functions to control differ ent circuit breakers becomes an easy and inexpensive process The inclusion of the AND function provides blocking and interlocking logic which further enhances the power of the scheme logic W ith this scheme logic design the functions of the logic inputs and relay outputs can be used in any fashion required by the application A facility is therefore provided for the user to enter a label to identify each of these inputs and outputs The
320. nt le gt should be set in accordance with the selected CT ratio to provide adequate primary sensitivity for the minimum possible inter turn fault current For similar reasons the time delay applied should be similar to that recommended for application of the main current operated element of normal stator earth fault protection The generator differential protection function would need to be connected as illustrated in Figure 7 to economise on CT s A set of CT s for each group of windings must be connected in parallel to drive other LG PG111 protection functions CT s for other protection functions Note The inter turn fault protection will also respond to some earth faults Figure 11 Inter turn Fault Protection Service M anual R5942B LG PG 111 2 4 2 4 1 Chapter 3 Page 24 of 75 Neutral voltage displacement protection function 59N I 59N 2 Summary e Voltage operated e Single measuring element two time delay stages e Immune to third harmonics e Applied to directly connected generators Supplied from a broken delta VT The voltage setting should be greater than the effective setting of any down stream earth fault protection A time delay sufficient to allow downstream earth fault protection to operate first should be used Fast earth fault protection can be enabled when the generator is not connected to the rest of the system e Applied to in directly connected generators Supplied from the se
321. nterlock with the directional earth fault must be removed Similarly to test the directional earth fault the interlock with the stator earth fault must be removed During the secondary injection testing the output relays of the LGPG111 will operate Therefore isolate the tripping circuits to the circuit breaker AVR and turbine Isolate alarms or indications as necessary Ensure VT s are isolated before injection and that the primary CT s are shorted Voltage balance Block Voltage balance Comp 44 yay 2 gt 64993 yh ze gee oan yo 43 saad ae sa RERARRRS RBBB Ss emoosddd Piddddoe zeverve L 0 Mo lofolojojojo o o o oJo o o o o o o o o oJo o ofoljolofolojojo oJojojojoJojo ojojojololo L1 0 jolololololo jolofofololololo o o lmlololofolo jolololololololo ofolololololo jololololo L 2 o o ofo jojojojo jojofo fo mfo o ojojojojojojojo ojojo o o o o o ojojojojojojo o o o o mfo o INPUT MATRIX 0 UTPUT MATRIX Latched Outputs 0 0 0 0 0j0 0 0 0 0 0 0 0 0 0 Fault Record Trigger OO o olololo 0000000 A larm T rigger o o o o o o o o o o o o jimmy Figure 1 Illustration of plain tripping logic LO blocking logic L1 and interlocking logic L in the scheme logic Protection function operation time can be measured from an MM LG test block if one is installed or from the panel terminal block or directly from the relay terminals During secondary injection tes
322. ntpole alternator with multiple pole pairs would be directly driven During electrical power system changes the type of prime mover and its associated speed governing facilities will have great influence on the dynamic performance of the generating plant There are many forms of generating plant that have evolved to exploit the common sources of energy available e g combustion of fossil fuels hydro dams and nuclear fission Generation schemes may be provided for base load production peaklopping or for providing standby power W hilst large scale generating schemes still meet the base load needs of most national power utilities there is a growing move towards smaller scale schemes to utilise otherwise redundant heat gases or combustible material resulting from many modern industrial processes Changing national legislation and utility tariff structures can also create an economic environment whereby large industrial consumers of electrical power find encouragement to operate their own generating plant to contribute to or to offset the demand on a utility supply at certain times of national peak demand for electrical power As a result of environmental concerns much effort is currently being expended with research into the efficient reliable and economic generation of electrical power using new forms of renewable energy All the above factors coupled with traditional industrial power generation requirements result in wide ranging demands f
323. o lolololo olola olofolo lololol lolololo lololojlo ynd yy ololc o jajajaja ojofolo jofofojo ojojojo olojolo lo o lojo olojojo G inding GY ojojojo ojojojo ojojojo ojojojo ojojojo ojojojo ojojojo ojojojo 9 dn OA lojojojo ojojojo o jojojo o jojo jo ojojojo ojojojo ojojojo o jojojo L Ndo LY lololojo lololol jofofojo lololojo jojojojo jojojojo lojojojo lololojo 8 ndn 8J olojlojlo jolojolo olololo jolololo olololo olololo ojolojo ojojojo 6 Nd NO 6A ololojo jolojolof jojojofo loj olojo jaolojolo jojojojo lololol jolojojo OLIAGINO OLY lolololo olofolo lolololo olololo Jofololo olofolo folololo lolololo LLANO LLY ojojojo o jojojo ojojojo ojojojo o jojojo o ojojo ojojojo ojojojo Jaaow aud Guy zty lololol lolo lo lolololo olololo olololo olololo pe dup eiye eleele ols lojell ololojo olololo olololo Z dD dup tL Ecem Seller e SS ojojojo o jojojo ojojojo ojojojo Lgo GLY fee ee fele ele l eese olofolo lollo o lojolo olololo L ndu ELI Jofololo lolo olo lolo olo lo ololo lo ololo jolololo ololojo lolololo ZL ndu ZLI ololojo o jojojo ojojojo o ojo jo ojojojo ojojojo ololojo ojojojo LL Ndu LLI ojojojo ojojojo ojojojo ojojojo ojojojo ojojojo ojojojo ojojojo OL mdu OLI Jojojojo jolaolalo o ojojo jojojojo olojojo olojojo ololo o o jojojo l lolololo lololol lololol lololol lololol lololol lololol lolololo 6 ndul l ololojo jol
324. o measure the pick up and drop off phase angles Record the phase angles measured Pick up phase angles RCA 90 with a 5 tolerance Drop off phase angles RCA 95 with a 5 tolerance O perating region RCA 90 to RCA 90 with a 5 tolerance Go to Section 7 5 3 unless the 67N is dual polarized Measurements and characteristic for polarizing current le Record the directional earth fault settings Iresidual gt RCA and lep gt Inject 0 2A into the input terminals A5 A6 and rated current into the input terminals A7 A8 Adjust the phase difference between the two current inputs so that the phase angle meter reads leigu leading by RCA degrees where RCA is the setting applied to the relay Record and check the currents measured by the relay allowing a 3 tolerance Accept and reset all alarms M easurement of Iresidual gt W ith the connections and phase angle set as above inject 0 2A into the input and inject zero Amps into the input Slowly increase current to measure its residual residual Service M anual R5942C LG PG111 Chapter 8 7 5 3 7 6 Page 31 of 66 pick up and drop off values Accept and reset all alarms pick up value lresidual gt setting with a 5 tolerance residual drop off value 0 95xlresidual gt setting with a 5 tolerance ee Measurement of lep gt W ith the connections and phase angle set as above inject rated current into the besiguai
325. o the display of the cell For binary flag type displays these two messages have the additional qualifier view appended which indicates that the gt arrow key may be pressed This enters a mode very similar to the binary flag setting mode except that the T amp J arrow keys have no action the flags cannot be changed The view mode allows the display of the name of the selected bit flag and with every display update the status of the flags is updated Thus the state of a named flag can be monitored The RESET key cancels this mode Some of the front panel s cell displays have a at the bottom right hand side and no value This is because the value consists of more than 16 binary bit flags which will not fit on the display Although for consistency in the scheme logic the 15 binary output flags are treated in this fashion Pressing the arrow key causes the display to be replaced by up to 32 bit flags Bit 31 Bit 16 0000000000000000 0000000000000000 Pi bs Bit15 Bit 0 The lt arrow key can be pressed to return to the cell s normal display or the arrow key to enter setting mode for the cell This could resultin the password protected or nota setting messages detailed above Default Display Menu Contents Section Contents GENERATOR SYSTEM DATA PROTECTION t AUXILIARY Date 1994 Jan 01 FUNCTIONS gt Time 00 00 03 E The clock consists of six fields the sand keys move between Date 1
326. o the fact that the winding voltage with respect to earth is low in this region The time characteristic and setting of the main current operated protection element le gt should be set to prevent false operation during HV system earth fault clearance where a transient generator earth connection current may appear as a result of the inter winding capacitance of the generator step up transformer The protection element should also co ordinate with operation of generator VT primary fuses fora VT primary earth fault and with VT secondary fuses for a secondary earth faulton a VT that has its primary windings earthed Depending on the VT fuse characteristics and on HV system earth fault protection clearance times a definite time delay anywhere between 0 5s and 3 0s would be appropriate The additional measuring element le gt gt would typically be set to operate with a primary current equal to 10 of the maximum limited earth fault current The time delay for this element t gt gt would typically be set to zero A higher current setting or time delay may be required in cases where VT fuse co ordination would otherwise be infringed In machines with complex winding connection arrangements e g some hydrogenerators the probability of a fault occurring in the stator winding star end region first 5 of the winding might be higher For a highly rated expensive machine such increased probability may prompt operators to apply 100 stator earth
327. o those functions provided by the LGPG111 For example when refurbishing the protection on some old designs of generator with external excitation connections to the rotor winding there would be a requirement for rotor earth fault protection Thermal overload protection is also not catered for in the LGPG111 package since directacting resistance temperature devices are usually applied with a monitoring unit supplied with the generator W here there exists the possibility of over fluxing a generator transformer over fluxing protection should be incorporated with the transformer protection For large generator applications the integration of the LGPG111 may be seen asa potential disadvantage in terms of the small but finite probability of the complete package failing Although the probability of failure is small the ensuing costs of plant downtime could be high in relation to the cost of providing the protection for a large baseload generator In such applications it would be prudent and economically viable to duplicate the protection packages and operate them from independent auxiliary power supplies see Figure 2 Such an arrangement would offer the full protection redundancy thatis normally provided for primary transmission systems but which has not been traditionally provided for generating plant The past strategy for avoiding outages due to protection problems has been to rely on multifunction discrete relays rather than on complete protect
328. oaded metering class current transformer 5 5 1 Protection class current transformers For less sensitive power function settings gt 3 P_ the Current input of the LG PG 111 should be driven by a correctly loaded class 5P protection current transformer To correctly load the current transformer its VA rating should match the VA burden at rated current of the external secondary circuit through which it is required to drive current Use of the LGPG111 phase shift compensation feature will help in this situation 5 5 2 Metering class current transformers For low power settings lt 3 P_ the enstive Current input of the LGPG111 should be driven by a correctly loaded metering class current transformer The current transformer accuracy class will be dependent on the reverse and low forward power sensitivity required Table 4 indicates the metering class current transformer required for various power settings below 3 P To correctly load the current transformer its VA rating should match the VA burden at rated current of the external secondary circuit through which itis required to drive current Use of the LGPG111 phase shift compensation feature will help in this situation Reverse and low forward Power Setting Metering CT Class P gt and P lt P 0 2 0 1 0 4 ojo olon AN OJO A ANOO oO ol N 0 Nje PPP NIN NN 1 0 Table 4 Sensitive reverse power current transformer requirements Servi
329. of disturbance recorder data capture modes W hen magnitude and phase data are selected for recording the measurements from the differential protection function inputs can be up to 5ms out of step with the rest of the measurements This is because the two groups of calculations are not time aligned internally inside the relay The recorder can be set to trigger on the energisation of relay output contacts and logic inputs Both triggers are user selectable Trigger on de energisation is not available A command is also available in the Disturbance Recorder menu Section to allow the user to trigger the recorder manually Records can be cleared with the Clear All Records command in the Disturbance Recorder Section of the menu Real time clock The relay runs a real time clock in software The clock provides the time and date for the recording functions with a 1ms resolution The clock has no battery backup Therefore it must be set up every time the auxiliary power is switched on W hen the relay is powered up it performs the following 1 Defaults the date and time to 1 January 1994 00 00 00 000 2 Generates a real time clock invalid event record 3 Displays a DATE AND TIME NOT SETUP message on the front panel s display The clock can be set through the menu or by a Set Time function provided by the remote access system Once the clock is set two event messages are logged and the message on the front panel is remove
330. ojofo jolajofo jolojojo o ojlojo jolojojo jolalojo jolojojo BI ololojo jofalojo jofolojo jofaofajo jofolojo jojololo jojololo lololojo g indu g Jololojo jofolojo jofolojo jofofojo jofolojo jojolojo lololojo ololojo Zi elelele jeleleje jeleje e jejoje e jojefojo sjojojo ojojojo jojojojo Z ndul ZI lololojo lolojojo jolojalo lojojlojo lololojo jajojolo lo ojojo lojojojo 9l ioj ojolo jolalajo lojololo jojofojo lolojlolo ojojojo jojojojo lojojojo 9 ndu 9l olololo o jojojo o jojojo o jojojo o jojojo ojojojo ololojo o jojojo dwog asunjog aboyo 09 jelele e jojojolo ojojoj ojojojo joj ojo jejejeje olojojo ojojojo 20 g e2uDjOg eBoyjoA 09 ol lolo jolo lo folololo ojolof jolololo ololojo olololo olololo a2unjog B oA 09 jolalojo jofalojo jojojojo jojofojo olol jaojololo jojololo lojolojo SAN ID4 p214 OV ololojo jofojolo jolololo jololol jaclojojo olojolo ojolojo ojojojo dag aauisuag zg elelee elelele jejejeje jelo e elele s slelele jejejeje eje eje juawasndsiq Onan z N6 eleli elelels jelelele jerjele olelele alelole olejolo clolc o junwarndsiq OuINAN L N s elelee eleleie jejejeje clele e jejejeje e e jejo jejejeje jejejeje INDY yog 10pos lt lt N LG elejeje ojojojo ojojo o jojo jo ojojojo ojojojo ojojojo ojojojo n04 yoa 10405 lt NLG lelelojo ojojolo ol o io o olojo ojojojo e ol ojo jolajojo ol
331. ojojo dul SdN lt lt 9V jojojojo ojojojo oj ojo ojojojo ojojojo ojojojo ojojojo ojojojo WIDID SIN lt 9 Jolalolo lololol olol lololol lololol lololol lololol lololol BOJjOA 13AO 6G lololol lololol lolololo lololol ololelo lolololo lololol lolololo aBoOYOA apun 7z elele leleleie elelete elelele je ejeje jeleiele e e e jeo elelele Anuanbay sapuq Z NLg elele elz ele fejle ejjel ele e e slojolo ejejej o jejejeje Anuanbead sapuq Aig lejele e eleje jelelelo elelolo ololo o jejejeje jolojojo ojololo u nb JAAD OL lejoje jolelojo ojojojo jojololo ololojo ojolfolo jololo o olojojo ABMOg pomo MOT IZE Olololo lej o ojo fojojolo je olojo oje lojo jajajaja jajaojojo jojojojo 1 MOd BS1J9A9q JZE jolo jo o jojojo ojojojo ojojojo ojojojo elelee ojojojo ojojojo u311Nn019AO ALG Jol lojo ojojojo olaololo ololojo o jojojo ojojojo ojojojo ojojojo 4ua p JOJOJBUBLT 9 28 lololo olofolo lolololo lolololo olololo lolololo loolololol lolololo s399 S885 sagg J935 Sss5 8589 SSSI 337 OUTPUT MATRIX INPUT MATRIX 1 0 0 0 0j 0 o0 o 0 0j0 o0 1 1 0 0 0 0 0 0 0 0 0 0 o0jojo o0 1 1 0 O O O O O O0 0 O
332. oltage Balance Thus outputs R15 and R4 can operate when the 32Land 40 operate Adding the 60 to the scheme input scenario should cause the outputs to drop off Alternatively by removing either of the 40 or 32L protection functions should cause the outputs to drop off as well Procedure for testing the scheme logic Record the scheme logic Input and O utput M atrix settings in the test results in Error AutoText entry not defined from the setting schedule provided Check the settings applied on the relay against the setting recorded Check the Scheme Setting is O K in Test Functions Section fix any logic lines which are reported as being in error Based on the Input M atrix settings recorded design the various test patterns or scenarios for the scheme test and record them in Error AutoText entry not defined Based on the input scenarios and the scheme O utput M atrix settings record the expected scheme output for each test For each test pattern enter the input scenario into the Set Events for Scheme Test cell and then press the SET key Press the 4 key to display Scheme 0 P Record the Scheme O P bit pattern observed on the relay and check it against the expected output pattern Service M anual R5942C LG PG111 Chapter 8 11 Page 63 of 66 For example using the settings given in Section 10 1 Figure 2 if the following bit pattern was entered into the Set Events for Scheme Test cell
333. oning Test Results 90005 1701 109 Technical Data 50005 1701 110 Drawings Issue control Engineering document number 50005 1701 001 Issue Date Author Changes AP February 1995 Dave Banham Original BP February 1995 Dave Banham Commissioning Instructions updated CP June 1995 Dave Banham General update N PS description changed Technical data updated and expanded Commissioning results record seperated from the commissioning instructions This is now a seperate _ chapter A July 1995 Dave Banham Styles Publicity B Feb 1996 Dave Banham General update Publicity Contents Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Publication R4106 forms part of this manual General Description Handling and Installation Application N otes Functional Description Hardware Description User Interface Fault Finding Instructions Commissioning Instructions Commissioning Test Results Technical Data Drawings CHAPTER 1 GENERAL DESCRIPTION Service M anual R595942A LG PG111 Chapter 1 Page 2 of 5 ISSUE CONTROL ENGINEERING DOCUMENT NUMBER 50005 1701 101 Issue Date Author Changes AP February 1995 Tony Yip Original BP June 1995 Dave Banham Minor update A July 1995 Dave Styles Banham Publicity Service M anual LG PG111 1 2 Contents IN TRO DUCTION LG PG 111 IN TEG RATED GEN ERATO
334. only finite memory in which to store event and fault records W hen this memory is full new records will overwrite the oldest records Disturbance recorder N ew settings have been rejected 1 The analogue channel selection cell will not be accepted if more than 8 chan nels are selected The disturbance recorder can record between 0 and 8 ana logue channels selected from the 17 analogue inputs Check the setting and try again 2 litis not possible to change the configuration of the disturbance recorder when it is in the process of making a recording Try changing the settings again after a few seconds Cannot access disturbance records at the front panel user interface Itis not possible to examine disturbance records on the LG PG111 s front panel user interface Disturbance records can only be extracted from the relay through the remote user interface No disturbance record generated or records lost 1 Check the disturbance recorder triggers are set up correctly 2 The relay has lostits DC auxiliary supply after the recording was made Unlike event records the disturbance records are stored in volatile RAM memory and will be lost when power is removed from the relay The length of the disturbance record is shorter than expected W hen the time interval between two consecutive triggers is less than the duration of a disturbance record the second record will have a shorter length This is due to the pre fault time of the seco
335. ontrol Limited or to a recognised service centre for calibration ALARM Exception Comms H W Fail The interface between the main processor and the communication processor has failed The remote communications has been disabled Reset the relay by power down and up again to see if the fault is persistent If unsuccessful replace the faulty microcomputer module The module should be sent back to ALSTOM T amp D Protection amp Control Limited for repair ALARM Exception Grp Sel I P Fail The setting group select pair of logic inputs are in an inconsistent state This could be due to an external wiring fault or a failed status input The currently active setting group remains active If after testing one of the status inputs is found to be faulty the analogue and status input module should be sent back to ALSTOM T amp D Protection amp Control Limited for repair An attempt to write to the EEPROM memory in the microcomputer module has failed Replace the faulty module with another The module should be sent back to ALSTOM T amp D Protection amp Control Limited for repair N on volatile EEPROM memory error alarm messages N on volatile EEPROM errors occur when there is corruption of information stored in the memory of the microcomputer module Data is segmented into blocks in the EEPROM and each block has its own data integrity checksum Thus each block can suffer a failure without affecting the integrity of the en
336. or generator protection that are conveniently and economically addressed by the LG PG111 integrated protection package Service M anual R5942B LG PG 111 1 2 Chapter 3 Page 6 of 75 Protection of generators Electrical protection is required to quickly detect and initiate shutdown for major electrical faults associated with the generating plant and less urgently to detect abnormal operating conditions which if sustained may lead to plant damage Abnormal electrical conditions can arise as a result of some failure with the generating plant itself but can also be externally imposed on the generator Common categories of faults and abnormal conditions to be electrically detected are listed as follows N ot all conditions have to be detected for all applications MAJOR ELECTRICAL FAULTS i Insulation failure of stator windings or connections SECON DARY ELECTRICAL FAULTS Insulation failure of excitation system Failure of excitation system Unsynchronised over voltage ABNORMALPRIME MOVERORCONTROLCONDITIONS e Failure of prime mover O ver frequency O ver fluxing Dead machine energisation Breaker Flashover SYSTEM RELATED Feeding an uncleared fault Prolonged or heavy unbalanced loading Prolonged or heavy overload Loss of synchronism O ver frequency Under frequency Synchronised over voltage O ver fluxing Under voltage In addition to the range of electrical protection required for a generator varyi
337. or an alarm Differential 87G Volt dependent overcurrent 51V Fuse failure RL15 RL8 Figure 29 Example showing the blocking feature of the scheme logic Interlocking with the low forward power function Figure 30 illustrates a low forward power interlocking scheme for the steam turbine sets as explained in the chapter 3 In this example the differential protection is regarded as an urgent trip condition and is required to trip the steam valve and the circuit breaker simultaneously The field failure function is required to trip the steam valve directly butis to be interlocked with the low forward power function for tripping the circuit breaker Service M anual R5942B LG PG111 Chapter 4 Page 38 of 50 In the scheme logic set up Relay 14 is assigned to trip the steam valve and Relay 15 is assigned to trip the circuit breaker The differential function is connected to trip both Relays 14 and 15 The field failure function is connected independently to operate Relay 14 The connection of this function to Relay 15 however is gated with the output from the low forward power function Therefore under field failure conditions the circuit breaker will be tripped only when the power supplied by the generator has fallen below the setting of the low forward power Trip steam valve RL15 Rotor earth fault 64 o RLY Rotor alarm Rotor fault O Figure 31 Example showing the connection of the scheme logic to ex
338. otection function is blocked if the current exceeds 1 051 due to a sensitive current measurement limitation Low forward power protection function 32L This protection function is similar in nature to the reverse power protection function described above with a single phase measuring element which operates from the sensitive A phase measuring CT input see Figure 15 according to the following formula Vig 30 x lC AB AUACOSD 0 P lt V3 W here Vg Phase phase voltage signal used Current from sensitive input CT Angle between in export direction and V P lt LGPG111 low forward power threshold setting 1 phase secondary W atts STABLE OPERATE Figure 15 Low Foward Power Protection Function Characteristic The measuring element is followed by an adjustable time delay that can be set down to zero if desired This protection function is offered for those users who wish to interlock non urgent protection function tripping and possibly manual tripping of the generator breaker and excitation system Interlocking with a low forward power measuring element confirms that the mechanical drive has been cut Such an arrangement would ensure that there would be no possibility of generator set over speed when any restraining Service M anual R5942B LG PG111 Chapter 3 Page 41 of 75 electrical load is cut by electrical tripping W ith any generator tripping of the generator breaker and excitation system should
339. oth these systems provide a broad range of standard facilities which allow a user to Read or change relay settings Display measurement values Examine fault and event records Inhibit the relay outputs for testing Perform tests Print information through the parallel port Additionally the remote access interface provides further possibilities for using the data available in the LGPG111 SCADA type equipment can be interfaced and the measurement data provided by the LGPG111 used to annotate mimic diagrams Measurement values can be collected for trend and performance analysis Settings can be saved remotely and archived or transferred to further LG PG111 s to speed up relay configuration Throughout this Chapter the front panel user interface is generally referred to as the front panel and the remote communications user interface as the remote access Both user interfaces are collectively referred to as access methods The following sections describe the underlying philosophy and operation of each interface security considerations and finally a detailed description of the menu system A supplementary publication R6138 is available which provides a detailed technical view of the remote user interface menu The publication will only be required when remote terminal equipment such as RTUs and SCADAS are to be explicitly configured to exchange data with the LGPG111 PHILOSOPHY The underlying user interface for both systems is
340. pensating effect of over frequency might be limited The result may be that the generating plant is subjected to excessive flux for too long O ver fluxing protection might generally be applied with generator sets that are connected to a power system via a step up transformer In such cases transformer differential protection would be required This is nota function provided by the LG PG111 relay For such applications the KBCH transformer differential protection relay should be applied which includes inverse time over fluxing protection Interlocked overcurrent protection W here a single generator or small number of generators is the only source of infeed to the generating station main busbar difficulty may be experienced in co ordinating the voltage dependent generator overcurrent protection 51V with delayed overcurrent protection for circuits being fed from the generator bus Difficulty arises with dependenttime protection as a result of both sets of protection seeing similar levels of fault current for a feeder fault This may result in the voltage dependent protection being more sensitive to a close up fault which results in a phase phase voltage reduction O ne method of dealing with the above type of problem would be to employ voltag dependent overcurrent protection for the feeders from the generator busbar Another solution offered with the LGPG111 generator protection and KCGG KCEG feeder protection would be to block operation of
341. perating time Check the red Trip LED turns on and the yellow Alarm LED flashes when the relay operates Check ALARM Protection 81U 1UF appears on the display ignore other alarms Accept all alarms Record the Service M anual R5942C LG PG111 Chapter 8 7 10 3 7 11 7 11 1 Page 51 of 66 operating time obtained O perating time tl with a 5 tolerance 10 to 60mS Restore the original setting for Fl lt Repeat the tests for the 81U 2 if required with settings F2 lt and t2 O peration of output relays Inject rated voltage with rated frequency into relay terminals B27 B28 to operate the 81U 1 change setting Fl lt if necessary Check the operation of the output relays against the scheme logic settings Record the output relays operated Restore the original Scheme Logic settings if changed Restore the original setting F1 lt if changed Repeat for the 81U 2 if required 810 Over frequency There is one over frequency element which is used to back up the speed control governor when overspeeding occurs in the event of a severe loss of generator load Enable the 810 Over Frequency protection only If necessary change the scheme logic input matrix so that only the 810 will cause the output relays to operate Characteristic and operating time Record the over frequency settings F gt and t Measurement of F gt with a variable frequency supply Inject rated voltage with frequency below the F
342. possible following a system separation where a generator might experience fullload rejection whilst still being connected to part of the original power system The automatic voltage regulating equipment should quickly Service M anual R5942B LG PG 111 2 12 Chapter 3 Page 54 of 75 respond to correct the over voltage condition but over voltage protection is advisable to cater for a possible failure of the voltage regulator to correct the situation or for the possibility of the regulator having been set to manual control The worst case of generating plant over voltage following a system separation which results in fullload rejection could be experienced by hydrogenerators The response time of the speed governing equipment can be so slow that transient over speeding up to 200 of nominal speed could occur Even with voltage regulator action such over speeding can result in a transient over voltage as high as 150 Such a high voltage could result in rapid insulation damage Generation electrical plant should be able to withstand a 5 over voltage condition continuously The withstand times for higher over voltages should be declared by the generator manufacturer The LG PG111 time delayed over voltage protection function threshold V gt should typically be set to 100 120 of the nominal phase phase voltage seen by LGPG111 The time delay t gt should be set to prevent unwanted tripping of the delayed over voltage protection function
343. quantity for the sensitive directional earth fault function The input range for both CT s is up to 2 048xiIn N eutral VT input The neutral VT input V shown in Figure 3 is used for the neutral displacement function and as a polarising signal for the sensitive directional earth fault function Both functions require a sensitive measurement The input range is therefore limited to 25 6V rms to provide increased sensitivity for small signal levels Phase CT inputs Three CT s are used to measure the phase currents as shown in Figure 4 The measurements are used by the overcurrent and the negative phase sequence protection functions The phase A current measurement is also used by the field failure protection function Additionally if the three phase voltages collapse the input will be used by the frequency tracking algorithm The input range for the three phase CT s is up to 20 48xIn Sensitive A phase CT input A special A phase current input l sensitive 15 used by the reverse power and low forward power functions The input is used in conjunction with the V input to measure the A phase active and reactive power The input range is up to 1 024xIn The smaller maximum input level allows the input to provide the required sensitivity to measure accurately small active power even in the presence of a significant reactive power component Phase VT inputs The LGPG111 provides four VT inputs for measuring the line voltage
344. r detected by the background self monitoring The power on diagnostics is currently being executed N ote that this may result in a lock out situation The relay has been reset due to a failure of the analogue input module during run time The power on diagnostics is currently being executed The diagnostics is testing the RAM and EPROM memory devices Service M anual R5942B LG PG111 Chapter 6 9 2 Page 83 of 91 The relay has been reset due to a failure of the communication hardware during run time The power on diagnostics is currently being executed The diagnostics is testing the RAM and EPROM memory devices Power on diagnostic error messages The following are power on diagnostic error messages The occurrence of any one of these errors will cause the relay to lockout The microcomputer and serial communications module is faulty Replace and return itto ALSTOM T amp D Protection amp Control Limited for repair Service M anual LG PG111 R5942B Chapter 6 Page 84 of 91 Cause of failure Microprocessor fails self check Interrupt mask register fails read write test Interrupt priority register fails read write test Interrupt status register fails read write test Inter
345. r interface operational messages Various messages may occur on the front panel during the use of the menu system These messages are listed here with their respective meanings and possible actions Reference should also be made to the operational descriptions of the Alarm Scan and Menu Browse in Sections 4 3 1 page 10 and 4 3 3 page 12 respectively RESET To Clear Alarms Appears when the ACCEPT READ key is pressed during an Alarm Scan to read the next alarm message when the last one is displayed The RESET key can then be pressed to clear the messages Alternatively the ACCEPT READ key can be pressed to acceptthe alarms without clearing them ALARMS Still Active Appears if there are alarms which are still active after an attempt to acceptor clear them in the alarm scan The ACCEPT READ key must be pressed to return to the default display Password Protected Occurs when a password protected setting is blocked from enter setting mode as the password has not been entered to make the setting available for changing Press the lt key to abort the action Password Protected View Same as the Password Protected message but only occurs for binary flag type cells A further press of the key enables the labels of each binary bit flag to be viewed The lt key aborts the action Service M anual R5942B LG PG 111 9 5 9 5 1 Chapter 6 Page 86 of 91 Sorry Settin
346. r setting this compensation angle comp is detailed in the commissioning instruction but it will only be necessary to set this angle for sensitive reverse power protection For general application the compensation angle setting should be set to zero degrees The reverse power protection function needs to be time delayed to prevent false tripping or an alarm given during power system swings following power system disturbances or following synchronisation During certain asymmetric power system faults when balanced system operation does not exist it must also be recognised that the reverse power protection function may see an operating condition during a fault For example a C A fault with direct generator connection or an HV B N fault fed through a Yd11 step up transformer The time delay t must therefore be set longer than the clearance time of asymmetric system faults by back up protection plus any delayed reset selling tDO that may have been applied Such a time setting typically Service M anual R5942B LG PG111 Chapter 3 Page 39 of 75 Comparison Ld A10 a_sensitivel X al LGPG 111 Figure 14 Connections for sensitive reverse power protection 5s should also give stability of the reverse power protection function during power swings In some applications the level of reverse power in the case of prime mover failure may fluctuate This may be the case for a failed diesel engine To prevent cyclic initiatio
347. racteristic Change the scheme logic so that only the 46 gt gt N PS thermal trip will cause the output relays to operate Ensure that the setting 12 gt gt is set to 0 2 and that the setting K is set to 10 For measuring relay operating time allow atleast 4xKreset seconds between timings to allow the thermal element to reset allow to cool until the relay displays a thermal value off 0 N ote the thermal value will be reset to 0 if the auxiliary supply to the relay is switched off Inject 1 386 x rated current into the and inputs so that phases A and B are in anti phase terminals A11 A13 with A12 and A14 linked to obtain the relay operating time O perating time 16 125 seconds with a 10 tolerance 10 to 40ms Repeat the injection and check that the I2 measurement in the relay indicates 0 8 x rated current Voltage based protection The following instructions are for the testing the functions that are voltage based The functions that are exclusively voltage based are 81U Under frequency 810 O ver frequency 27 Under voltage 59 O ver voltage and 60 Voltage balance Service M anual R5942C LG PG111 Chapter 8 6 2 1 6 2 2 6 2 3 6 2 4 Page 19 of 66 M easurements Inject 20v into the V input and rated volts into the remaining voltage inputs Record and compare the voltage injected with the value measured by the relay Allowing a tolerance of 5 Input Terminals V B19 B20 Va B25 B26 Vi
348. rance Drop off voltage 0 95xVs with a 5 tolerance O peration of output relays for voltage balance prot Repeat the previous tests to operate the voltage balance protection VT fail element Check the operation of the output relays against the scheme logic settings Record the output relays operated Repeat for the comparison VT fail element Restore the original Scheme Logic settings if changed Service M anual R5942C LG PG111 Chapter 8 Page 58 of 66 8 LOGIC INPUT STATUS CHECKS O nly those logic input terminals which are wired in the protection scheme need to be checked Energize each logic input one by one Check the binary pattern in the Logic Input Status cell in the Auxiliary Functions Section is as follows Relay Terminals Logic Input Status Loe Ee ee B1 B2 00 0000 0000 0001 0010 0100 1000 0000 0000 0000 D5 D6 00 0000 1000 0000 D9 D10 ee 0000 D13 D14 R 0010 0000 0000 D15 D16 R 0100 0000 0000 D19 D20 R 1000 0000 0000 D23 D24 E 0000 0000 0000 D27 D28 Fe 0000 0000 0000 Table 3 Logic Input Status patterns for single input energization Service M anual R5942C LG PG111 Chapter 8 9 1 Page 59 of 66 CONTACT TEST These tests are to operate the output relays in turn Only the output relays which are wired in the protection scheme need to be tested All external relay contact connections from the p
349. rate in order for the internal timer to start The logic is shown in Figures 21 and 22 A logic input 27 81U Inhibit is provided which will inhibit the under voltage timer when energised The logic is illustrated in Figure 22 Figure 21 Over Voltage 59 operation logic 27 and 81U Inhibit Input Figure 22 Under Voltage 27 operation logic Settings and characteristic The settings provided by the under voltage and the over voltage functions are as follows Under voltage V lt Under voltage threshold T Timer setting Service M LG PG111 3 10 3 10 1 anual R5942B Chapter 4 Page 32 of 50 O ver voltage V gt Over voltage low set threshold t gt Low set timer setting V gt gt Over voltage high set threshold t gt gt High set timer setting The characteristics are illustrated in Figure 23 N ote that the over voltage element has a combined low set and high set characteristic with a single output NO TRIP a Under voltage b O ver voltage Figure 23 Under voltage 27 and over voltage 59 characteristics Under and over frequency 81U amp 810 General description Two independent under frequency elements and one over frequency element are provided The frequency elements obtain their measurements from the frequency tracking algorithm as discussed in Section 2 7 A logic input 27 81U Inhibit is provided which will inhibit the under frequency timers when energised The log
350. rating is obtained from the analogue input module and is provided for information only The relay can have a nominal current rating of either 1A or 5A 3 3 Differential CT ratio Scales the differential settings and the measurements made by the differential and bias CT s Service M anual LG PG111 3 4 3 5 3 6 3 7 3 8 3 9 3 10 R5942B Chapter 6 Page 37 of 91 Sensitive la CT ratio Scales the sensitive la input This input is used by the power measurement function in the LGPG111 the scaling affects the power settings and measurements The line VT ratio also affects these settings and measurements Residual CT ratio Scales the residual current measurement This input is used by the sensitive directional earth fault function and scales the lresidual gt setting Earth CT ratio Scales the earth path current measurement This input is used by the stator earth fault and sensitive directional earth fault functions The le gt le gt gt and lep gt settings are scaled by this value Earth VT ratio Scales the neutral displacement voltage measurement used by the neutral displacement earth fault protection The neutral displacement Ve gt and directional earth fault Vep gt settings are scaled by this value Phase CT ratio Scales the three phase current measurements and settings used by the overcurrent negative phase sequence and field failure protection The field failure impedance settings are also
351. rcurren Vs 33 V Vs 33 V 10 5 51V Overcurrent VsI 104 V Vs1 104 V 10 6 51V Overcurrent Vs2 33 V Vs2 33 V 10 7 51V Overcurrent K O25 K 0 25 10 8 51V Overcurrent Characteristic Char SI 10 9 51V Overcurren I gt 1 00 A I gt 1 00 A 10 10 51V Overcurren Og es Qd s 10 11 51V Overcurren TMS 1 00 TMS 1 00 10 12 51V Overcurren tRESET 0 tRESET Os Enabled Function Voltage Restraint Standard Inverse Dependent Overcurrent Table 26 The LGPG111 s Voltage Dependent O vercurrent Section of its menu Settings for the voltage dependent overcurrent protection function 10 1 Voltage dependent overcurrent status The protection function can either be enabled or disabled The setting is password protected 10 2 Voltage dependency function Determines the method of voltage dependency if any Service M LG PG111 anual R5942B Chapter 6 Page 54 of 91 Front Panel Remote Access 51V Overcurrent Function Voltage Controlled Fn Control Fn Restrain 51V Overcurrent Function Simple Overcurrent Fn Simple Table 27 States of the overcurrent function cell 51V Overcurrent Function Voltage Restraint In the voltage controlled mode cells 10 5 amp 10 6 are invisible Cell 10 4 is invisible in the voltage restraint mode and all three cells plus 10 3 amp 10 7 are invisible in the simple overcurrent mode
352. rcurrent Char DT Table 30 States of the overcurrent timing characteristic cell This setting is password protected Depending upon the value of the timer characteristic either cell 10 10 or 10 11 is visible cell 10 10 is visible for the definite time characteristic and cell 10 11 is visible for the standard inverse characteristic 10 9 10 10 10 11 amp 10 12 Timer characteristic settings Service M LG PG111 7 12 anual Power protection R5942B Chapter 6 Page 56 of 91 Table 31 The LGPG111 s Power Protection Section of its menu Settings for the reverse and low forward power protection functions Also includes a setting to compensate for any 11 1 Compensation angle phase error between the system CT amp VT Allows the LG PG 111 to correct any external phase error between its V and sensitive inputs which are used to calculate the power and phase angle measurements Can be set between 5 in 0 1 increments The setting is password protected and affects both the measurements and power protection functions Reverse power status The protection function can either be enabled or disabled The setting is password protected 11 3 11 4 11 5 Reverse power settings 11 6 Low Forward power Status The protection function can either be enabled or disabled The setting is password protected
353. rd n Allows an event record to be selected The last record is the record most recently stored n is an index counting away from the last record up to the number of records stored Thus Last Record 0 is always the most recent and Last Record 1 the next most recent and so on For a given record the View Records Section adapts to present the information about the event All records consist of a time stamp and one or more information cells If a new event record is generated whilst viewing a record the section s content will change A new record will cause existing records to increase their record numbers by one the new record becomes record zero and the old record zero becomes record one and so on The View Records Section always displays the selected record number so the addition of a new record causes the section to display the next newest record For example if viewing Last Record 1 and an event occurs the display will change to display the new Last Record 1 which was Last Record 0 lf there are no events stored then cell 6 10 is the only item visible and No Records Stored is displayed 6 3 Exceptions Various relay failures or exceptions Bit FrontPanelName Remote Access N ame 0 Uncalib Analog Uncalibrated Analogue Module 1 Analog Mod Fail Analogue Module Fail Calib Vector Err Calibration Vector Error Comms H W Fail Communications Hardware Fail Grp Sel I P Fail Group Select Input Fail
354. rd the neutral displacement protection settings t2 and t2RESET Ensure the output relay connected to the timer on the test set is operated by the 59N 2 and not by the 59N 1 Inject 2xVe gt Volts to obtain the relay s operating time Check ALARM Protection 59N 2 ND appears on the display ignore other alarms Reset all alarms O peration of output relays for 59N 2 Inject 2xVe gt Volts into the V input terminals B19 B20 to operate the 59N 2 Check Service M anual R5942C LG PG 111 7 8 7 8 1 Chapter 8 Page 36 of 66 the operation of the output relays against the scheme logic settings Record the output relays operated 51V Voltage dependent overcurrent The purpose of the voltage dependent overcurrent function is to disconnect the generator from the system if a system fault has not been cleared by the main protection after a pre determined time delay The voltage dependent characteristic can either be voltage controlled or voltage restrained and the timing characteristic can either be standard inverse or definite time W hen the generator is directly connected to the busbars the voltage controlled overcurrent function is used whereas if the generator is connected to the busbars via a step up transformer the voltage restrained overcurrent is preferred For applications that do not require a voltage dependent characteristic a simple overcurrent function can be used W ith voltage controlled overcurrent
355. record is stamped with the time and date of the event occurrence W hen the record buffers are full a new record will automatically overwrite the oldest one The types of events recorded by the relay can generally be divided into three groups power system events relay operational events and diagnostics events The power system events consist of the following e Protection function operation including the faulted phase information if applicable e Energisation of any relay output e Energisation of any logic input except the real time clock synchronisation input These events are recorded once every 5ms N ote that the reset of any protection function operation and the de energisation of logic inputs and relay outputs are not recorded Service M anual R5942B LG PG 111 9 3 Chapter 4 Page 44 of 50 The relay operational events consist of the following Power on reset or warm reset see Section 9 11 Realtime clock invalid or set Removal or restoration of password Setting group change State of the scheme output Enabled or Inhibited Events recorded by the diagnostics self monitoring functions are as follows Liquid crystal display LCD failure Watchdog timer inoperative or incorrect Analogue input module missing Analogue input module uncalibrated Analogue input module failure Communication hardware failure N on volatile memory EEPRO M write failure N on volatile memory EEPROM data corruption in
356. red that each individual function of the relay is tested as a discrete 5 2 relay the instruction contained in this section should be followed If the in service settings are not available at the time of commissioning then the instructions in section 7 should not be followed as they are designed to test the relay as it would be used in service Notes for secondary injection tests O nly the protection functions which are enabled in the application s protection scheme need to be secondary injection tested The LG PG111 has 15 programmable output relays However in checking their operation itis only necessary to test those which are connected in the external scheme O peration of the output relays can be checked with a continuity tester on the relay s terminal blocks Drawing 10 LGPG111 00 in chapter 11 shows the output relays and their corresponding terminal numbers The LGPG 111 is a multifunction relay If the relay is being tested as discrete units then only one protection function is enabled ata time Therefore only one protection function is tested ata time The protection function test method is similar to testing individual protective relays To enable a protection function set the functions Enabled Disabled setting to Enabled To disable a protection function setit to Disabled The original Enabled Disabled setting must be restored after the secondary injection tests have been completed Since only one protection functio
357. relay itis necessary to open the front panel and inspect the relay modules Before this inspection you should touch the earthed panel as a precaution against electrostatic voltages If modules are removed from the case an anti static wrist strap should be worn and the modules should be handled by the front plate frame or edge of the printed circuit boards to avoid contact with electrical components or connections Always store and transport modules in electrically conductive anti static bags Inspection W ith no DC auxiliary voltage connected carefully examine the relay to ensure that no damage has occurred during transit Check the front nameplate label for the correct model number and rating information e Vx 1 Rated voltage of auxiliary supply to the power supply module Service M anual R5942C LG PG111 Chapter 8 3 2 1 3 3 ces lly Page 9 of 66 e Vx 2 Rated voltage of auxiliary supply to the optically isolated logic inputs In Rated current of the CT s Remove the relay s cover and open the front panel by undoing the large screw on the right hand side of the front plate The equipment label on the back of the front panel lists the model number serial number firmware reference and details about the front panel and the modules fitted in the relay Check that the module references are correct and that the modules are fitted in the correct positions Record the relay s rating and serial number in the commissioni
358. relay operation This produces an operating time of typically less than 60ms Service M anual R5942B LG PG 111 Chapter 4 Page 34 of 50 3 11 2 Settings and characteristic 3 12 3 13 The setting provided by this function is Vs Voltage difference threshold The logic implemented by this function is IF Vo e V conaran gt Vs O R IF Vi V ecmganan gt Vs THEN comparison VT fuse failure IF Vo Vas ceriatiand lt Vs O R IF Vic 7 V becaria S Vs THEN protection VT fuse failure Timer hold facility The overcurrent stator earth fault and neutral displacement functions are all provided with a timer hold facility This allows for faster clearance of intermittent faults An example of which is a cable fault where the insulation breaks down heals breaks down again and heals again a number of times in rapid succession If the timer resets instantaneously the fault may remain undetected until it becomes permanent The timer hold facility allows the timer to hold its value when the fault clears provided the inter fault period is less than the t timer setting The tese timer setting is selectable from 0 to 60s in 1s steps The facility also enables closer co ordination with electromechanical induction disc relays A further application of this facility is to provide pole slipping protection During pole Slipping the systems current will pulsate widely An appropriately set overcurrent function with a suitable reset
359. rement as displayed in the M easurements 1 Section Enter this value into the compensation setting and check that the relay s phase angle measurement corresponds with the metering FINAL SETTING CHECKS Check the date and time on the relay is correct in the Auxiliary Functions Section If it is not set the correct date and time Check each protection function is Enabled or Disabled as specified in the setting schedule provided for service Service M anual R5942C LG PG111 Chapter 8 Page 66 of 66 Check the settings applied to the relay are correct against the setting schedule provided for service Check the Scheme Setting cell in the Test Functions Section is O K Record the settings applied to the relay in the commissioning test results Error AutoText entry not defined The LG PG 111 s printer facility is useful for this subject to a parallel printer being available Replace the relay s cover Chapter 9 Commissioning Test Results Service M anual LGPG111 Issue control engineering document number Issue AP Date June 1995 July 1995 June 1997 Author Dave Banham Dave Banham Publicity Andy Forshaw Publicity R5942B Chapter 9 Page 2 of 52 50005 1701 111 Changes Original W as included in the commissioning instructions 50005 1701 108 Styles Change of style Addition of new form Service M anual LGPG111 Contents COMMISSIO
360. remote access user interface Disturbance recorder Configuration settings for the disturbance waveform recorder Test functions Various test facilities Protection operation summary Provides protection operation status indications as a percentage time to trip N ote that all setting values measurements etc in the following sub sections are based on the 1A version of the LGPG111 Service M anual LG PG111 7 2 System data R5942B Chapter 6 Page 26 of 91 item Front Panel Remote Access 1 0 is DATA System Data 1 1 ene REN Password 1 2 Description Description LGPG111 Relay LGPG111 Relay 1 3 Plant Reference Plant Reference lt Not Defined gt lt Not Defined gt 1 4 Model Number Model Number LGPG11101S533LEA ee 11 5 Serial Number Serial Number 0000000 0000000 1 6 System Frequency System Frequency 55 Hz So HZ 1 7 Comms Level Communication Level 1 1 1 8 Relay Address Relay Address 1 a 1 9 Active Setting Active Setting Group 1 Group 1 hi 1 10 Software Ref 1 Software Reference 1 18LGPG002XXXEB 18LGPGO002XXXEB 1 11 Software Ref 2 Software Reference 2 18SCM001002A 18SCM001002A i 1 12 Logic I P Status Logic Input Status 00000000000000 00000000000000 1 13 Relay O P Status Relay Output Status 0000000000000000 0000000000000000 Table 6 The LG PG
361. ring element reset time delay tDO Complete loss of excitation may arise as a result of accidental tripping of the excitation system an open circuit or short circuit occurring in the excitation DC circuit Service M anual R5942B LG PG111 Chapter 3 Page 48 of 75 flashover of any slip rings or failure of the excitation power source A pure open circuit in the excitation system is unlikely to be long lasting in view of the high voltage that would be developed across the open circuit with the machine running and connected to a power system Such a fault is likely to evolve quickly into a short circuit fault W hen the excitation of a synchronous generator fails its internal e m f will decay This results in the active power output of the machine falling and in an increasing level of reactive power being drawn from the power system As the active power output falls the maintained mechanical drive will accelerate the machine so that it will gently pole slip and run ata super synchronous speed As the machine begins to run super synchronously slip frequency currents will be induced in the rotor body damper windings and in the field windings The slip induced low frequency rotor currents will result in a rotor flux being produced The machine would then be excited from the power system and would be operating as an induction generator The mechanical input torque following loss of excitation might not exceed the peak of the machine s speed torq
362. rm t gt 2S t gt Zc Table 34 The LGPG111 s N egative Phase Sequence Section of its menu Settings for the negative phase sequence protection 14 1 N egative phase sequence status The protection function can either be enabled or disabled The setting is password protected 14 2 N PS thermal trip A subtitle cell for the remote system only all the negative phase sequence thermal trip settings are indented below this 14 3 14 4 14 5 14 6 amp 14 7 NPS Thermal trip settings 14 8 N PS Alarm A subtitle cell for the remote system only all the negative phase sequence alarm settings are indented below this 14 9 amp 14 10 NPS Alarm settings Service M anual R5942B LG PG 111 Chapter 6 Page 60 of 91 7 16 Field failure Item Front Panel Remote Access 15 0 FIELD FAILURE Field Failure 15 1 40 Field Failure 40 Field Failure Enabled Enabled 15 2 40 Field Failure Xa Offset 2 500 Ohm Xa 2 500 Ohm 15 3 40 Field Failure Xb Diameter 250 0 Ohm Ohm 15 4 40 Field Failure t Pickup 3 0 S 15 5 0 Field Failure tDO Dropoff Os DO Os Table 35 The LGPG111 s Field Failure Section of its menu 15 1 Settings for the field failure protection function Field failure status The protection function can either be enabled or disabled The setting is password protected 15
363. ronous machines would be operated from a variable frequency supply when in pumping mode Additionally in the case of combined cycle generating plant it may be necessary to excite and synchronise a steam turbine generating set with a gas turbine set at low frequency prior to running up to nominal frequency and synchronising with the power system W hen LGPG111 protection functions are required to operate accurately at low frequency it will be necessary to use CT s with larger cores In effect the CT kneepoint voltage requirements will be multiplied by f f where f is the minimum required operating frequency and f is the nominal operating frequency In the case of a synchronous machine ata pumped storage plant being operated in the motoring mode it would be necessary to disable reverse power protection in this mode This could be accomplished by switching to the LG PG 111 s alternative group of settings where the reverse power protection function would not be enabled Service M anual R5942B LG PG111 Chapter 3 1 4 Page 9 of 75 W hen applying the LPG 111 the traditional scheme engineering and interrelay wiring costs associated with traditional discrete relay protection schemes are eliminated and a significant economy is made in required panel space For some applications not all the protection functions of the LG PG 111 would be applied For other applications some specialised additional protection might be required in addition t
364. rotection and can be energised during the start up and run down of the generator set The input can be driven by a normally closed auxiliary output contact of the circuit breaker W hen this input is energised the timers of the two under frequency elements and the under voltage element are forced into reset N ote that itis equally possible to block the operation of the under voltage and under frequency functions through the scheme logic using one of the non edicated logic inputs This is applicable to the dead machine protection scheme as described in the Application N otes chapter 3 W hen the generator is shut down the under voltage function is required to initiate the alternative setting group whilst its tripping and alarm initiation will be blocked by the normally closed circuit breaker auxiliary contact via the scheme logic Overcurrent timer inhibit 51V timer inhibit This input is used to inhibit the timer of the overcurrent function The input can be used in conjunction with the start element of K Series overcurrent relays to provide a simple blocking scheme W ith such schemes the start contact of a K Series relay on an outgoing feeder is used to block the overcurrent function from operating until the fault is cleared This allows the LGPG111 s overcurrent function to be setin a fast operating definite time mode whilst still grading with overcurrent protection on the outgoing feeders see Figure 31 Block for earth fault 51
365. rotection 32R RP appears on the display Ignore other alarms Reset all alarms Record the operating time O peration time the setting t allowing 5 tolerance 0 to 120mS O peration of output relays Repeat the previous injection test to operate the 32R relays Check the operation of the LG PG111 s output relays against the scheme logic settings Record the output relays operated Restore the original Scheme Logic settings if changed 32L Low forward power Low forward power is sometimes applied to steam turbines where sequential shutdown is preferable under less urgent operations to avoid over speeding Low forward power is a balanced condition and therefore single phase measurement of the condition is sufficient The relay calculates Vicoso from the A phase inputs In order to provide the required sensitivity a separate current input is used A compensation angle setting is provided to allow for phasing errors of the generators CT s and VT s Enable the 32L Low Forward Power protection only If necessary change the scheme logic input matrix so that only the 32L will cause the output relays to operate There is no need to change the input matrix for blocking by the Voltage Balance element M easurements The 32L Low Forward Power uses l sensive and V p to calculate the active power in the A phase As there is no input for V the relay calculates it from the V input by dividing by V3 and rotating by 30 Inject rated
366. rror alarm messages The following three diagnostic errors are considered to be minor Hence alarms are raised instead of locking out the relay _Display _ Diagnostic alarms ALARM DiagnosErr The check on operation of LCD has failed The front panel LCD Fail user interface is disabled ALARM DiagnosErr The watchdog is found to be inoperative Watchdog Inop ALARM DiagnosErr The watchdog timer is found to be fast Watchdog Fast Table 55 Diagnostic error alarm messages Chapter 7 Fault Finding Service M anual LG PG111 ISSUE CONTROL R5942C Chapter 7 Page 2 of 14 ENGINEERING DOCUMENT NUMBER 50005 1701 107 Issue June 1995 July 1995 feb 1996 April Author Dave Banham Dave Banham Dave Banham Publicity Dave Banham Publicity H JBurke Publicity O riginal M inor corrections Styles Changes Added notes concerning relay output modules in their correct mo on short disturban dule positions Added notes ce record lengths Section 2 2 inclusion of new tolerance data in table Service M anual R5942C LG PG111 Chapter 7 Page 3 of 14 Contents 1 INTRO DUCTION 5 1 1 Problem analysis 5 1 2 Fault finding procedure 5 1 3 initialisation sequence 6 2 PO W ER ON FAILURES 6 2 18 Power supply checks 6 Dias Front panel checks 7 2 3 M ain microprocessor checks 7 3 O PERATIO N AL FAILU
367. rupt timer control register fails read write test Interrupt DMA 0 control register fails read write test Interrupt DMA 1 control register fails read write test Interrupt INT 0 control register fails read write test Interrupt INT 1 control register fails read write test Interrupt INT 2 control register fails read write test Interrupt IN T 3 control register fails read write test An unexpected interrupt has occurred Timer 2 is inoperative Timer 2 is fast Timer 2 is slow No DMA 0 interrupt occurred DMA 0 transfer error RAM memory error EPROM memory error Table 49 Power on diagnostic lock out errors Service M anual R5942B LG PG111 Chapter 6 9 3 9 4 Page 85 of 91 Run time default display messages There are three default display messages These override the normal default display which is detailed in Section 4 2 page 9 ALARM This message can be flashing or stable W hen itis flashing there is a new alarm W hen itis stable either alarms have been accepted and not cleared or there is an alarm which is still active and cannot be cleared DATE AND TIME NOT SET UP Displayed at default level when there are no alarms and the date and time has not been set Local Settings Unlocked Displayed at default level when the password has been entered at the front panel user interface all the password protected settings are now available for changing Use
368. ry to test each relay individually as there were no common elements however with the LG PG 111 the separate protection functions share common hardware and software functions and as such it is only necessary to test the LG PG111 as one unit Detail of these test are given in Section 6 However if the customer requires each individual element can be tested and details of these tests are given in section 7 It should be noted that there is significant reducation in commissioning and outage times if the instructions in section 6 are followed For maintenance test it is recommended that the tests in section 6 are used The commissioning engineer should read both section 6 and section 7 in consultation with the end customer Service M anual R5942C LG PG 111 Chapter 8 Page 12 of 66 decide which instructions to use If the in service settings are not available at the time of commissioning then the instruction in section 7 should not be followed as are designed to test the relay as it would be used in service Section 6 This section gives details of the tests the manufacturer recommends for the site testing of the relay these tests are designed to prove the correct operation of both the hardware and software functions This section should also be used as the basis of any maintenance tests It should be noted that there is a significant reduction in commissioning and outage times if these instructions are followed Section 7 If itis requi
369. s Ic Mean Bias T2 I Residual Ie Vab Vbc Vca Ve Active Power Reactive Power Phase Angle Frequency End of Report th Fault 51N gt gt Stator Ear e 60 Voltage Balance Comp atus Trip CB NPS Alarm Under Freq Trip Overcurr tus No operation Enabled Group 1 1 000 A 1 000 A 1 000 A 998 mA 1 000 A 997 mA 500 mA 500 mA 500 mA 0 A 1 003 A 1 002 A 110 1 V 0 V LTO 3 V 0 43 V Aph 5o29 W Aph 31 60 VAr Aph 29 9 deg 44 49 Hz R5942B Chapter 6 Page 81 of 91 C 51V Overcurrent A ncy th Fault NPS Trip ent Trip Gen Dif Service M anual R5942B LG PG 111 Chapter 6 Page 82 of 91 SUMMARY OF FRONT PANEL USER INTERFACE MESSAGES Relay reset messages The following messages are displayed when the relay is powered up cold reset or when itis reset by the watchdog warm reset The relay has been powered up from cold and is carrying out the power on diagnostic tests The relay has been reset by the operation of the watchdog and is currently carrying out the warm reset diagnostic tests The relay has been reset due to a RAM error detected by the background self monitoring The power on diagnostics is currently being executed N ote that this may result in a lock out situation The relay has been reset due to an EPROM erro
370. s The first press of the key as prompted brings up the value 0000000000000000 Protection scroll left and right as required 0000 _ Not A Setting 0000000000000010 View _ 87G Gen Diff olv oc lt 0 0000000000000 lt 00000000000000 Figure 11 Example of the front panel menu browse procedure Examining binary flag type cells Service M anual R5942B LG PG111 Chapter 6 5 1 Page 17 of 91 Default Display M enu Contents Section Contents GENERATOR SYSTEM DATA PROTECTION E AUXILIARY FUNCTIONS J 87G Gen Diff Enabled 87G Gen Diff Isl 0 05 A Setting Mode Values given for a 1A relay model The T amp Jarrow keys adjust the value of the setting For example The Tarrow increases the value 87G Gen Diff T 87G Gen Diff T 87G Gen Diff isti 0 05 44 Isl 0 06 A Isl O O07 A The Jarrow decreases the value 87G Gen Diff l 87G Gen Diff I 87G Gen Diff Isl 0405 A Isl 0 50 A Isl O 49 A The display value has rolled over between its limits Figure 12 Example of the front panel menu browse procedure Changing a value setting REMOTE ACCESS USER INTERFACE For detailed information about how to use a particular remote access software package please refer to that package s user manual Typical features of remote access software The remote access system is based on the ALSTOM T amp D Protection amp Control Limited Courier co
371. s Two consecutive calculations are required to confirm a relay operation This produces an operating time of typically less than 65ms Service M anual R5942B LG PG111 Chapter 4 3 4 2 3 5 3 5 1 Page 21 of 50 Settings and protection characteristic The settings provided by this function are as follows lresidual gt Residual current threshold Used as the operating quantity RCA Relay characteristic angle Applied only to the Ve polarising quantity Vep gt Threshold for the neutral voltage polarising quantity lep gt Threshold for the neutral current polarising quantity The tripping criteria are as follows All three criteria must be satisfied for the relay to Operate 1 Ve gt Ve gt or le gt le gt 3 Olresidual Ve RCA lt 90 If voltage polarised Olresidual lel lt 90 If current polarised The characteristic is shown in Figure 12 lResidual Trip IResidual gt gt 90 RCA RCA 90 RCA Note The horizontal axis represents the angle of the operating quantity with respect to the polarising quantity The RCA setting applies to Ve polarising only For le polarising the RCA is 0 Figure 12 Characteristic of the Sensitive Directional Earth Fault function Voltage dependent overcurrent 51V General description The voltage dependent overcurrent is a three phase function used for system back up protection The current signals are the three phase currents from
372. s X Generator direct axis transient reactance in primary ohms The above guidelines are suitable for applications where a generator is operated with a rotor angle of less than 90 and never ata leading power factor For generators that may be operated at slightly leading power factors and which may be operated with rotor angles up to 120 by virtue of high speed voltage regulation equipment the settings would need to be different The impedance characteristic diameter Xb should be set to 50 of the directaxis synchronous reactance O 5X and the offset Xa should be set to 75 of the direct axis transient reactance O 75X The field failure protection time delay t should be set to minimise the risk of operation of the protection function during stable power swings following system disturbances or synchronisation However it should be ensured that the time delay is notso long that stator winding or rotor thermal damage will occur The stator winding should be able to withstand a current of 2 0 p u for the order of 15s Itis unlikely that rotor damage would be incurred in much less time than this It must also be appreciated that it may take some seconds for the impedance seen at the generator terminals to enter the selected characteristic of the protection function However a time delay less than 10s would typically be applied The minimum permissible delay to avoid potential problems of false tripping due to stable power swings with
373. s as shown in Figure 4 Two VT s are used for the measurement of the phase to phase voltages V and Ve The measurements are used by the under and over voltage functions the voltage dependent overcurrent function and for frequency tracking The V voltage input is also used to derive the A phase to neutral voltage for the power and field failure protection functions Two other VT inputs are provided Vo comparison AND Viccomparison TNESE inputs are used by the voltage balance function for comparison with the protection VT inputs All four VT s are designed to have an input range of up to 204 8V rms Service M anual R5942B LG PG111 Chapter 4 Page 10 of 50 Vab Comparison Vp C LG PG111 Figure 4 Phase currents and voltages typical input connection Service M anual R5942B LG PG111 Chapter 4 2 2 2 3 2 4 Page 11 of 50 Anti aliasing filters W hen an analogue signal is sampled at discrete time intervals the original signal s content is preserved for up to half of the sampling frequency Frequencies above this become aliased as lower frequencies because the frequency spectrum folds at half the sampling frequency The effect of frequency aliasing or folding is for higher frequencies to impersonate lower ones and cause distortion Prevention of aliasing is accomplished by band limiting the input signal so that it has no significant frequency content above half the sampling frequency Band limiti
374. s into reset mode The logic is shown in Figure 9 The low set element is also provided with an adjustable timer hold facility which is explained in Section 3 12 Settings and protection characteristic The settings provided by this function are as follows 51N gt Low set Characteristic Selection for either standard inverse or definite time characteristic le gt Threshold setting for the low set element t gt Definite time delay for use if definite time characteristic is selected TMS Time multiplier setting for use if the standard inverse is selected tRESET Reset time for the timer hold 51N gt gt High set le gt gt Threshold setting for the high set element t gt gt Definite time setting for the high set element The setting for omoun the function of the 51N inhibit input is located in the Auxiliary Functions Section of the menu Stator EF Timer Inhibit Selection for inhibiting the low set element timer the high set element timer or both timers The standard inverse timing characteristic is defined as 0 14 t TMSx _ym ___ seconds I Ie gt 1 The ADC saturates at 2 048xIn which results in the composite timing characteristic of Figure 10 y ie ene aces Cian Rar e e eee COIS MCN Cone e O perating Time Seconds o Current M ultiple of Setting Figure 10 Stator earth fault low set element standard inverse timing characteristic Service M anual R5942B
375. s A11 A12 to obtain the operating time Check the yellow Alarm LED is flashing and ALARM Protection 46 gt NPS appears on the display ignore other alarms Reset all alarms O perating time t gt setting with a 5 tolerance 10 to 40mS Repeat the tests for the input terminals A13 A14 and the input terminals A15 A16 O peration of output relays for 46 gt N PS alarm Repeat the injection described previously to operate the 46 gt NPS Alarm Check the operation of the output relays against the scheme logic settings Record the output relays operated Characteristic and operating time for 46 gt gt N PS thermal trip If necessary change the input matrix in the scheme logic so that only 46 gt gt Thermal Trip will cause the output relays to operate Record the negative phase sequence settings 12 gt gt K MAX tMIN and Kreset M easurement of 2 gt gt Inject 3 x 12 gt gt Amps into the input terminals A11 A12 Slowly increase the current until the 46 gt gt N PS Thermal Trip picks up The Protection O peration Summary Section Service M anual R5942C LG PG111 Chapter 8 Page 46 of 66 of the relay s menu can be used to determine this without the need to wait for timer operation N ote that the displayed value must be 100 as this is an indication of thermal capacity As it may take some time to reach 100 more current may be injected to warm up the relay Inject several times 12 gt gt
376. s external connection diagram and nn is the connection arrangement The drawing numbers for the mounting details and for the arrangement diagrams are also given below All the above diagrams can be found in chapter 11 10LGPG11100 External connection diagram GM0008 sht 1 Outline and mounting details of 4U modular case rack mounting sht 2 Outline and mounting details of 4U modular case panel __ mounting GM0054 025 LGPG111 arrangement diagram rack mounting GM0055 023 LGPG111 arrangement diagram panel mounting Table 2 Diagram reference numbers Service M anual R5942B LG PG111 Chapter 5 3 Page 7 of 23 RELAY DESCRIPTION The LG PG 111 is housed in a single tier 4U 178mm high rack or panel mounting case The relay consists of 6 modules a hinged front panel and a rear case mounted module Module Position Function Power Supply Unit O utput Module 1 1 2 3 O utput Module 2 4 Microcomputer and Serial Communications 5 6 Status Input M odule Analogue and Status Input M odule Front panel User Interface Rear Case mounted Communications Isolation Module Table 3 Module numbering and description The arrangement diagrams show the relative positions of the modules within the case External connections for CT VT output contacts and status inputs are made via standard 28 way M IDO S connectors mounted on t
377. s is unless the neutral voltage displacement protection function is used to provide this coverage with a long time delay see Section 2 4 1 Figure 9 shows the single line diagram of the system used for the co ordination example given in Figure 10 W here difficulty is experienced in co ordinating the generator stator earth fault protection function with outgoing feeder earth fault protection and where KCGG KCEG relays are used to protect outgoing feeders it may be possible to eliminate the co ordination problems by interlocking the feeder protection with the generator protection as described in Section 3 4 In the case of direct generator connection itis common that only one generator of a parallel set is earthed at any one time with the earth connections of other machines left open If the generating plant can also be run directly in parallel with a medium voltage public supply itis a common requirement that all generator earth connections are left open during parallel operation In such circumstances the main earth fault protection element le gt will only be operational for an earthed machine It will provide primary earth fault protection for the associated machine backup earth fault protection for other machines and the rest of the power system and thermal protection for the earthing resistor For directly connected generators that could be earthed there is no need to employ the additional earth fault protection element le
378. s no longer asserted W hen the LG PG111 has output the entire report to the printer the print status will return to stopped The cell can be reset at any time to cancel the selected print request Examples of print reports can be found in Section 8 page 75 Event reports are printed in reverse chronological order the most recent event is the last one in the report This allows reporting on a real time system to a slow output device For example a request for 10 event records causes the report generator to start at the tenth record W hen there are less than 10 event records the report starts at the oldest record The report finishes when the most recent event record has been printed if events occur during printing these will also be printed Thus a request for 10 event records could result in the printed report containing more or less than 10 records The same is true for the other event reports Service M anual LG PG 111 R5942B Chapter 6 Page 34 of 91 2 9 2 10 Front Panel Remote Access 5 rt Print Print Stopped Stopped 2 2 ll Print Print Printing Printing we Print Print Printer Busy Printer Busy fe ll Press SET To Prn Print Print System Settings System Settings a il Press SET To Prn Print Print Protection Settings Prot Settings Press SET To Prn Print Print Scheme Settings Scheme Logic
379. s not used in the scheme logic there is no requirement for the following 46 gt NPS Alarm tests If necessary change the scheme logic input matrix so that only the 46 gt N PS Alarm will cause the output relays to operate Record the 46 gt N PS Alarm settings I2 gt and t gt M easurement of 12 gt Inject 3 x 12 gt Amps into the I input terminals A11 A12 Slowly increase the current Service M anual R5942C LG PG111 Chapter 8 7 9 3 7 9 4 Page 45 of 66 until the 46 gt NPS Alarm picks up Record the pick up current W ith the relay operated slowly decrease the current injected until it resets Record the drop off current As there is a time delay associated with this function the Protection O peration Summary Section of the relay s menu can be used to determine the point at which this function starts to operate The Protection O peration Summary should indicate 0 when the current injected is increased to the pick up point the displayed percentage will start to increase this is the pick up point the displayed value will rise from 0 and displays 100 when the time delay has expired Accept and reset all alarms Pick up current 3 x 12 gt setting with a 7 5 tolerance Drop off current 2 85 x 12 gt setting with a 7 5 tolerance Repeat the tests for the input terminals A13 A14 and the input terminals A15 A16 M easurement of operating time Inject 6xl2 gt Amps current into the I input terminal
380. s uploaded by a remote access system after which the buffer is cleared for recording again N ote that the disturbance record cannot be examined through the front panel user interface The records will also be lost if the relay loses its auxiliary power A record consists of one timer channel two digital channels and up to eight analogue channels The timer channel is used to time tag each sample The two digital channels record the status of the fourteen logic inputs and the status of the sixteen relay outputs respectively in binary bit format The eight analogue channels are selectable from the relay s seventeen analogue inputs The sixteen outputs consist of the 15 scheme logic outputs bits 1 15 and the relay inoperative output bit 0 Service M anual R5942B LG PG 111 9 7 Chapter 4 Page 46 of 50 The disturbance recorder can be set to capture either the raw data or the magnitude and phase of the selected analogue inputs The raw data is acquired every sample whereas the magnitude and phase are captured at 20ms intervals The features of these two types of recording are shown in Table 4 Analogue Data Data Type Record Length Record Duration Raw data Digitised data direct 768 samples 64 cycles at12 from ADC without Samples per cycle calibration M agnitude amp Derived calibrated 384 samples 7 68 seconds at phase quantities after 20ms intervals Fourier filter Table 4 Comparison
381. scheme and in the burdens imposed on the current and voltage transformers If the integration is extended to include the scheme logic the amount of interrelay scheme wiring and auxiliary components is also reduced This further minimises the design and installation costs and simplifies maintenance and commissioning test procedures The use of digital technology and the integration of a number of protection functions offers further benefits local and remote instrumentation event fault and disturbance recording testing aids self documentation of settings and serial communication facilities for remote access All these features can simplify the tasks of commissioning testing trouble shooting and post fault analysis Thus by providing more information more readily the protection unit is made more useful LGPG111 INTEGRATED GENERATOR PROTECTION The LGPG111 relay integrates a number of common generator protection functions and the scheme logic into the same relay case The selection of the protection functions is designed to cover a wide range of generators which avoids the need for application specific relay versions From the user s view point this simplifies the relay specification evaluation and project planning From the development view point the work is concentrated on a standardised model thus allowing the relay to be more rigorously tested due to its internal fixed software architecture Service M anual LG PG111 R5942A Chap
382. scheme logic of Figure 2 presented as relay ladder logic Testing the scheme logic of Figure 2 with the scheme test facility in the Test Functions Section proceeds as follows Service M anual R5942C LG PG 111 Chapter 8 Page 62 of 66 For logic word LO Logic word LO has only one 1 bitin its input AN D word and hence is an independent operation In the example of Figure 2 the 1 isin the 87G Generator Differential position so by setting up a scenario for 87G operation outputs R15 and R1 should operate For logic word L1 Logic word L1 has more than one 1 bit setin its AND word and hence some form of interlocking or blocking logic is being formed Closer examination reveals that the negated 60 Voltage Balance is selected which implies blocking logic with the selected 51V Voltage Dependent O vercurrent Thus outputs R15 and R2 should operate when only the 51V operates By adding the 60 operation to the scheme test scenario the 51V should be blocked and the outputs R15 and R2 drop off For logic word L2 Logic word L2 represents interlocking logic between the 51N gt gt and the 67N Thus an input scenario with both operated should cause output R15 to operate Removing either one should cause R15 to drop off For logic word L3 10 2 This represents the 40 Field Failure interlocked with the 32L Low Forward Power However the loss of a protection VT fuse is catered for with a blocking action from the 60 V
383. sed as Isin t 6 itcan be shown that the Fourier sine and cosine components are a vector representation of the signal on the complex 2 i iy S Ic cost xi 2 n plane i e Zo Is jic and Is Icoso Ic Ising For the LGPG111 the sampling rate is 12 samples per electrical cycle i e N 12 Therefore the corresponding Fourier equations are UNA Sass oe Stee Oe ast ve kd F 3 tisi hy BG tiiit F It Glos oe 5 he de PROT E E E T ine te Ffa isie tio G hein tinie ti i From the Fourier sine and cosine components the magnitude and the phase quantities of a signal can be calculated Itis also possible to derive various power system quantities such as active and reactive power and the sequence components Some protection characteristics such as the sensitive directional earth fault and field failure can be implemented directly from the Fourier components of the relevant signals Figure 5 shows the frequency response characteristic of the 1 cycle Fourier filter As shown in the Figure the response of the Fourier filter to the 11th and the 13th harmonics is the same as the fundamental due to the aliasing effect The composite response of the Fourier filter together with the two types of anti aliasing filters is shown in Figure 6 Itcan be seen that the effects of aliasing are very much reduced Service M anual R5942B Chapter 4 LG PG111 Page 13 of 50 5 6 7 8 9 10 11 12 13 Multiples of Fundi
384. sequence into the main microprocessor module During this procedure the integrity of the data is checked Any errors are reported and depending upon the level of data corruption the relay may attempt to run the protection with no calibration or to stop the protection and take itself out of service Communications checks The remote access user interface is provided by the main processor and a slave communications microprocessor controlling a serial communications interface A simple go no go test is easily performed by trying to establish communications in the normal fashion preferably on one of the two rear ports The front port can be used if there are no suspected faults in the ribbon cable bus or in the front panel For the RS232 IEC60870 based communications the configuration of the serial channel baud rate etc should match at both ends RS232 test boxes with indicator LED s can be useful in establishing whether the fault lies with the master end or the Slave relay end Care should also be taken with the wiring of RS232 connection leads since there is no standardisation on the orientation of the transmit and receive pins Standard connection leads can normally be obtained in either a straight or crossed arrangement A straight or through lead connects the pins of the connector at one end through to the same pins of the connector at the other end A crossed lead interchanges the receive and transmit connections In all cases itis ad
385. settings Here there are several solutions Private communications links and modems with dial back facilities could be used Ultimately though the LGPG111 does provide the facility to disable remote setting capability This means that all setting changes must be done through the relay s front panel However it does still allow the remote interface to be used to monitor the relay and associated generator set Inactivity timers There are two inactivity timers one for each access method W hen a defined period of inactivity has elapsed the particular access method is reset For the local access Service M anual R5942B LG PG111 Chapter 6 Page 21 of 91 method this involves restoring the default menu state cancelling local setting mode and retocking password protected cells For the remote access method this just involves the previous two items except that remote setting mode is cancelled instead The two timers are fully independent but share one setting which can be setin the range 5 to 30 minutes in 5 minute increments Local access inactivity is defined as the time between successive key presses Remote access inactivity is defined as the time from entering setting mode to pre loading a new value or aborting setting mode and from pre loading a new value to executing or aborting it Additionally the timer is started when the password protected cells are unlocked The timer is also restarted whenever the menu is browsed with the read
386. settings are disabled the group 1 identifier 1 is removed Service M anual R5942B LG PG111 Chapter 6 Page 72 of 91 20 6 Scheme logic Group 1 test event input Allows scheme logic input scenarios to be setup The scheme logic processes this and the output is displayed in the next cell The names of the input bits are identical to those used in the scheme logic input AN D matrix see Table 38 page 63 This test can be performed with the LG PG111 protection fully functional and with no ill effect W hen alternative settings are disabled the group 1 identifier 1 is removed 20 7 Scheme logic Group 1 test output The scheme logic output bit pattern resulting from the input scenario of the above cell The names of the output bits are identical to those used in the scheme logic output O R matrix see Table 37 page 62 W hen alternative settings are disabled the group 1 identifier 1 is removed 20 8 20 9 20 10 amp 20 11 Group 2 scheme logic tests Identical to cells 20 4 to 20 7 respectively except that the tests are applied to the group 2 scheme logic settings W hen the alternative setting group is disabled these cells are invisible Service M anual LG PG111 7 22 Item Front Panel Protection operation summary Remote Access R5942B Chapter 6 Page 73 of 91 21 0 PROTECT
387. ssor module is constantly checked for integrity If an error is found an EEPROM error alarm message is logged in the event recording system Errors detected during relay operation have no direct effect because the relay is using volatile RAM copies of the data Errors detected during power on will cause the faulty area to be reset with default data and hence will require that lost settings are reinstated Front panel checks A faulty front panel can be identified by visual inspection and use of the key pad Failure of the display driver may result in an inoperative front panel user interface The remote user interface should be still functional though O peration of the LED indicators can be tested with the lamp test option in the Test Functions section of the relay s menu see chapter 6 Care should be taken to ensure the two relay output modules are inserted into their correct module positions the LG PG 111 will apparently function correctly with the modules swapped except the wrong contacts will be operated Relay output module checks Contacts on each relay output module can be energised manually with the relay output test option in the Test Functions section of the relay s menu see chapter 6 Isolate all tripping and alarm circuits before performing this test Logic input status checks The 14 optically isolated logic or status inputs to the relay are divided between the status input module and the analogue and status input modu
388. stable delay on trip timer reset tDO is also provided this would normally be set to zero The low forward power protection function can be arranged to interlock non urgent LG PG111 tripping using the relay logic matrix see Figure 16 Itcan also be arranged to provide a contact for external interlocking of manual tripping if desired Negative phase sequence thermal protection function 46 Summary e Protects the rotor of a generator from damage resulting from the heating effects of negative phase sequence currents e Provides true negative phase sequence thermal protection and a definite time alarm e Accurate over a wide system frequency range e The trip threshold should be set slightly higher than the constant negative phase sequence current withstand of the generator e The protection must be time graded to allow downstream protection to clear an unbalance fault e To achieve easier grading with down stream protection during clearance of a heavy asymmetric fault a minimum operating time for the negative phase sequence protection can be set e For negative phase sequence currents slightly above setting a maximum trip time can be set e Can provide back up protection for uncleared asymmetric faults e Models the cooling characteristic of the generator following exposure to negative phase sequence currents e The alarm element is commonly set to 70 of the trip setting with a time delay well above the time ta
389. t 4 An internal relay can be heard to operate when a contact test is performed yet the operation of the contact can not be detected Firstly check that the correct relay has been operated by the test and the corresponding terminals are identi fied correctly Secondly ensure the two relay output modules have been inserted into their correct module positions and not swapped over 4 11 Communications 4 11 1 Cannot establish communications Check the following 1 2 The communications port selected on the relay matches the physical connection For RS232 IEC60870 based communications the correct RS232 lead crossed or uncrossed is being used If a modem is connected check the cor rect control signals are present The correct IEC60870 baud rate is selected The correct relay address is selected The relay will not communicate when its address is set to 255 Check the frame length 10 or 11 bit Most simple modems will only accept 10 bit frame lengths whereas the LGPG111 only provides 11 bit framing to conform to the IEC 60870 standard Check the modem s setup If the modem will not connect check that the line is not engaged Also check the correct telephone number is being used complete with dialling codes W hen dialling from a PBX private branch exchange ensure local dialling prefix codes are dialled e g for external line access On some exchanges it is necessary to pause between requesting an external line a
390. t Pick up Pick up Level Level gt KI gt 2 6 1 gt Kl gt Vs Voltage Vs2 Vs1 Voltage level level Voltage controlled mode Voltage restrained mode Figure 12 Voltage Dependent Overcurrent Functions In the voltage controlled protection mode see Figure 12 a step change in current setting I gt to K I gt is imposed when the monitored voltage signal drops below an adjustable threshold setting Vs In the voltage estrained protection mode see Figure 12 a progressive change in current setting is made I gt to K I gt for voltage variation between the upper threshold Vsl and the lower threshold Vs2 This mode is analogous to under impedance backup protection especially where a definite time delay is applied Under impedance protection is a more familiar method of providing backup protection for some operators The voltage dependent overcurrent protection function 51V is also provided with a characteristic timer hold setting tRESET The percentage operation of the characteristic timer following the current rising above the operating threshold of the protection for a period is held for time tRESET if the current subsequently falls below the operating threshold before tripping has occurred This feature will allow the protection to respond to the cyclic application of fault current in the event of flashing or pecking faults It can also be used to ensure that the voltage dependent overcurrent pro
391. t gt Os 59N Neutral Displacement Disabled Ve gt 1V Els 1 0 S E23 ls t2RESET Os 67N Sensitive Directional EF Enabled Iresidual gt SmA RCA 0 deg Vep gt 1V R5942B Chapter 6 Page 50 of 91 Service M anual R5942B LG PG111 Chapter 6 Page 51 of 91 Item FrontPanel lt Remote Access 9 20 67N SDEF Iep gt 5mA Iep gt 5mA Table 24 The LGPG111 s Earth Fault Protection Section of its menu Settings for stator earth fault neutral displacement and sensitive directional earth fault protection functions 9 1 Stator earth fault status The protection function can either be enabled or disabled N ote that protection function implies both the low set and high set elements it is not possible to disable just the low set element The high set element may however be selectively enabled or disabled by cell 9 8 The setting is password protected 9 2 Low set A sub title cell for the remote system only all the stator earth fault low set settings are indented below this 9 3 9 4 9 5 9 6 amp 9 7 Low set characteristic settings Cell 9 3 specifies the timing characteristic for the low set element This setting is password protected Front Panel Remote Access 51N gt SEF Low Set Characteristic Standard Inverse Char SI i 51N gt SEF Low Set Characteristic Definite Time Char DT
392. t close to the generator will result in a fault current decrement the system voltage should be monitored to distinguish between normal load current and a system fault Here either the voltage controlled or the voltage restrained modes of operation should be selected Voltage controlled overcurrent protection A step change in the current setting is initiated if the system voltage falls below a selected level Applied when the generator is directly connected to the system At normal system voltage the current setting should be 5 above full load current Under low voltage conditions the current setting should be reduced to less than 50 of the minimum steady state fault current The reduction in the fault current setting is controlled by a multiplying factor K The voltage control threshold should be selected to ensure that a voltage reduc tion due to a single phase to earth fault will not result in a change of the current setting W hen negative phase sequence protection is also applied the calculation of the voltage threshold need only consider the effect of a remote three phase fault Service M anual R5942B LG PG111 Chapter 3 Page 29 of 75 e Voltage restrained overcurrent protection The current setting is incrementally decreased as the voltage falls below a selected level A lower voltage level is also defined below which the current setting will remain ata minimum value The pick up current for a given voltage below
393. t the previous injection test as appropriate to operate the 51N gt gt Check the operation of the LGPG111 s output relays against the scheme logic settings Record the output relays operated 59N Neutral Displacement This function is applicable to a generator which is earthed via a distribution transformer loaded with a resistor to limit the earth fault current O peration is by measuring the voltage developed across the distribution transformers loading resistor Enable the 59N Neutral Displacement protection only If necessary change the scheme logic input matrix so that only the 59N 1 will cause the output relays to operate M easurement checks Ensure that the neutral transformer is isolated from the panel terminal block before beginning these tests Inject 20V from the panel terminal block into the V input terminals B19 B20 Record and check the voltage injected and the voltage measured by the relay allowing 3 tolerance Characteristic and operating time for 59N 1 Record the neutral displacement protection settings Ve gt and tl Measurement of Ve gt Inject 0 8 x Ve gt Volts into the V input terminals B19 B20 and slowly increase the voltage to measure the 59N 1 gt pick up value Decrease V to check the drop off value As there is a time delay associated with this function the Protection O peration Summary Section of the relay s menu can be used to determine the point at which this function starts to
394. t to that of the operating current threshold This current level can be translated into a neutral voltage as described for the neutral voltage protection function in Section 2 4 1 W here the protected generator can be earthed the current polarising signal threshold setting lep gt in primary amps should be less than 5 of the maximum current that could be delivered through the generator earthing impedance for a solid earth fault on a generator terminal If the protected generator can never be earthed the current polarising signal threshold setting should be set to maximum 0 02In The directional element characteristic angle setting RCA should be set to match as closely as possible the angle of zero sequence source impedance behind the relaying point If this impedance is dominated by an earthing resistor for example the angle setting would be set to zero degrees In the case of a generator that will not be earthed and where a dedicated core balance CT is not available to drive the sensitive directional earth fault protection function the LGPG111 scheme logic should be set up so that operation of both the first stage of the neutral voltage displacement protection function 59N 1 and the Service M anual R5942B LG PG111 2 6 Chapter 3 Page 28 of 75 directional protection function 67N is required before a trip command is given The group 1 time setting for this protection should be chosen to give adequate trip stability in t
395. te the 40 Field Failure element Check the operation of the LGPG111 s output relays against the scheme logic settings Record the output relays operated 67N Sensitive directional earth fault W hen two or more generators are connected in parallel directly to the busbar the sensitive directional earth fault function is used in conjunction with either the stator earth fault or the neutral displacement to discriminate between internal or external faults The operating quantity is the residual current measured at the line end of the generator The polarizing quantity is derived either from the voltage input of the neutral displacement function or the current input of the stator earth fault function depending on which is available Enable the 67N Sensitive Directional Earth Fault protection only If necessary change the scheme logic input matrix so that only the 67N will cause the output relays to operate If is used as the polarizing current go to Section 7 5 2 unless the 67N is dual polarized in which case both V and polarizing tests should be carried out Measurements and characteristic for polarizing voltage V Record the directional earth fault settings Iresidual gt RCA and Vep gt Inject 20V into the V input terminals B19 B20 and rated current into the terminals A7 A8 input residual Adjust the phase difference between the volts and the current so that the phase angle meter reads leading V by R
396. tection function will respond to cyclic overcurrent conditions during pole slipping as discussed in Section 3 5 1 The basis for the two modes of voltage dependent protection function is really historical originating from the two convenient ways of achieving voltage dependency with electromechanical relay technology However for different applications subtle advantages are often claimed for one form of protection over the other Application of the voltage controlled overcurrent protection function In this mode itis relatively easy to determine the behaviour of the overcurrent protection function during a fault since it merely switches between a load characteristic and a single fault characteristic This protection mode is ideally suited to applications where there is a significant phase phase voltage collapse at the generator terminals for a busbar or feeder multi phase fault This would be the case where a generator is directly connected to the busbar The LGPG111 voltage controlled current setting is related to the measured voltage as Service M anual R5942B LG PG111 Chapter 3 Page 31 of 75 follows For V gt Vs Current setting Is I gt For V lt Vs Current setting Is K I gt W here Is Current setting at voltage V V Voltage applied to relay element The operating time characteristic of the protection can be set as definite time or inverse time according to the following curve formula 0 14 el 2 Is T
397. tem Data Section of the menu correspond with the numbers printed on the identification label attached to the back of the front panel found by opening the front panel If they are different enter the relay s password then change these two settings to correspond with the numbers on the label Check also that the system frequency setting in the System Data Section is set appropriately The LGPG111 can display its settings and measurements in terms of the systems primary or secondary voltages and currents These commissioning instructions require injection levels to be calculated from the protection settings The settings are assumed to be in secondary terms for this purpose Check the Display Value cell in the Transformer Ratios Section is set to Secondary for the duration of these commissioning tests If both setting groups are used set the Active Setting Group cell in the Auxiliary Functions Section to 1 and perform the injection tests If necessary the injection tests can then be repeated for the group two settings by setting this cell to 2 N ote thatitis only possible to change the Active Setting Group cell in the menu when the Select Setting Group cell is set to Menu If itis set to Logic Input then either set it temporarily to Menu and proceed as before or use the group select logic inputs to control which setting group is active Service M anual R5942C LG PG 111 6 1 6 1 1 Chapter 8 Page 16 of 6
398. tep up transformer is used to indirectly connect the generator to a power system The voltage dependent overcurrent protection function can be set to operate in a voltage controlled mode or in a voltage restrained mode If voltage dependency is not required this function can be set to operate as plain overcurrent protection with a fixed operating characteristic The protection function can be set to operate with an adjustable standard inverse time characteristic or with a definite time delay In the case of a generator passing highly reactive current to a fault the level of fault current can fall below the maximum possible machine load current within 0 5s 1 0s unless a fastacting automatic voltage regulator AVR is available This is because the AVR is able to boost the level of field excitation during a fault The problem of fault current decrement can be most acute when the excitation supply is derived from a transformer connected to the generator terminals W here a fault current decrement is possible voltage dependent overcurrent protection provides time delayed backup protection with adequate sensitivity for a multiphase busbar or feeder fault whilst remaining stable for the highest anticipated level of generator load current The generator terminal voltage is monitored as a way of being able to distinguish between normal load and system fault conditions Service M anual R5942B LG PG 111 Chapter 3 Page 30 of 75 Current Curren
399. ter 1 Page 5 of 5 The mix of protection functions provided Figure 1 is designed to produce a cost effective solution for a wide range of application problems Each protection function can be enabled or disabled to suit individual requirements Some functions such as 100 stator earth fault and rotor earth fault have not been provided in this relay since they are not standard in the majority of applications W hen these functions are specified additional discrete relays will be required W ith this in mind the relay provides the ability to integrate external devices into its scheme logic so that tripping facilities together with local and remote alarm facilities can be utilised Key 27 32L 32R 40 46 51N 51V 59 59N 60 67N 810 81U 87G Under voltage Low forward power Reverse power Field failure Negative phase sequence Stator earth fault Voltage dependent overcurrent O ver voltage Neutral voltage displacement Voltage balance Sensitive directional E F O ver frequency Under frequency Generator differential Figure 1 Protection functions provided by the LG PG 111 CHAPTER 2 HANDUNG AND INSTALLATION Service M anual R5942A LG PG111 Chapter 2 Page 2 of 6 ISSUE CONTROL ENGINEERING DOCUMENT NUMBER 50005 1701 102 Issue Date Author Changes AP February 1995 Dave Banham Original BP June 1995 Dave Banham Minor Update A
400. ter 6 Page 38 of 91 VAr deg Table 15 The LG PG 1111 s Measurement1 Section of its menu Provides all the fundamental measurements which the LG PG111 has obtained or derived from its inputs All magnitude values for the voltages and currents are rms values of the measured fundamental all harmonic components have been removed by signal processing 4 1 Date amp time This cell only appears on the remote access menu W hen the remote system reads this section it captures a snapshot of the measurement values this cell provides a time stamp indicating when the data was captured This is nota problem for the front panel since the display is updated approximately every 500ms Service M anual R5942B LG PG111 Chapter 6 Page 39 of 91 4 2 4 3 amp 4 4 Three phase current The magnitudes of the three phase currents 4 5 4 6 amp 4 7 Three phase voltage The magnitudes of the line to line voltages V and V are measured di rectly and V is derived from them 4 8 Earth path current The magnitude of the earth path current 4 9 N eutral displacement voltage The magnitude of the neutral displacement voltage 4 10 Residual current The magnitude of the residual current 4 11 N egative phase sequence current Calculated magnitude of the negative phase sequence component 4 12 4 13 amp 4 14 Power amp Phase angle Calculated active power reactive power and phase angle in the A phase The Power Section contains a se
401. ter end The transmission wires should be terminated using a 150Q resistor at both extreme ends of the cable Cable polarity TerminalNo Connection E K Bus 1 2 K Bus 2 SCN notconnected Table 8 K Bus connections Polarisation is not necessary for the twisted pair Maximum cable length The maximum cable length for a spur is 1000m Service M anual R5942B LG PG111 Chapter 5 5 4 1 6 5 4 1 7 5 4 1 8 5 4 1 9 Page 13 of 23 M aximum devices per spur The maximum number of devices per spur is 33 This ordinarily allows for one master connection and 32 slaves The LG PG 111 constitutes as a slave device RS232 IEC870 connection Connection method The RS232 portis suitable for direct point to point connection between the LG PG 111 and either a PC or modem The pin out of the rear porton the relay is configured as a Data Terminal Equipment DTE the connections are listed in Table 9 Earthing arrangements The earthing arrangement of the RS232 connection is for the protective ground to be connected to OV and also to the relay case This arrangement provides maximum screening of the RS232 signals Pin Function Direction N umber 1 Protective ground 2 Transmitted data TxD O ut 3 Received data RxD In 4 Request to send RTS Out 5 Clear to send CTS In 6 Data set ready DSR In 7 Signal ground GND 8 Data Carrier Detect DCD In 20 Data terminal ready DTR O ut Table 9 Con
402. ternal devices Service M anual R5942B LG PG111 Chapter 4 4 2 3 Page 39 of 50 Interfacing external devices The LG PG111 can be used in conjunction with external devices by way of any one of eight logic inputs Rotor earth fault protection for example see Figure 31 is not provided by the LGPG111 However by using one of the logic inputs the operation of an external rotor earth fault relay can be monitored and included within the scheme logic of the relay It is possible for external devices to block or interlock with the relay s own protection functions RELAY OUTPUT OPERATING TIME The 15 relay outputs assigned to the scheme logic have different operating and reset times Ten relays Relays 3 7 11 15 have a fast operating time of 2ms The tripping outputs should be selected from these relays The operating time of the other relays is 8ms and can be used for alarms All relays are capable of tripping circuit breaker coils All the relay outputs are provided with a minimum dwell time of 100ms Thatis once a relay has operated the contact will remain closed for at least 100 ms This is to preventa relay output breaking circuit breaker trip coil current if the controlling meas uring element resets too quickly Relay Pick Up Time Drop Off Time 1 8ms_ 8ms ie 22 8ms 8ms l 3 2ms 2ms l 4 2m_ 8ms 5 2 1 ing I 8ms 6 2ms 8ms l 7 2ms 8ms l 8 8m 8ms
403. the above impedance settings would be of the order of 0 5s Some operators have traditionally interlocked operation of impedance type field failure protection with operation of under voltage detection elements in order to allow a low field failure protection time delay without the risk of unwanted tripping for stable power swings This arrangement may also have been used to prevent field failure protection operation for hydrogenerators that may be run as synchronous compensator s with the turbine mechanically decoupled Such interlocking would be possible with the LGPG111 under voltage protection function by appropriate configuration of the scheme logic A better approach would be to switch to the second group of relay settings when running as a compensator where the field failure protection function could be disabled In some hydrogenerator applications the operation of field failure protection may be blocked by operation of an over frequency detection element This is to prevent maloperation of traditional forms of impedance protection elements during transient over frequency running that might result from power system separation Hydrogenerators could experience speed frequency excursions up to 200 of nominal following rejection of full load Such interlocking could be offered with the LG PG111 over frequency protection function elements and appropriate setting of the scheme logic The field failure protection function is offered with an
404. the generator voltage dependent overcurrent protection function 51V if the feeder overcurrent protection picks up This can be accomplished by allowing feeder protection start contacts to act on the logic input for blocking the LG PG 111 voltage dependent overcurrent protection function 51V as illustrated in Figure 25 An adequate co ordination time margin must be Service M anual R5942B LG PG 111 Chapter 3 Page 64 of 75 allowed between the voltage dependent protection function operating time for a close up fault and the operating time of the feeder protection instantaneous start contact W here time delayed feeder overcurrent protection is insensitive to a feeder fault with a generator decaying infeed the feeder protection start contact would not operate and the voltage dependent generator protection function would be free to provide the required backup protection In a similar manner to arranging for interlocked overcurrent protection difficulties in co ordinating the LG PG 111 time delayed stator earth fault protection function 51N with feeder earth fault protection in the case of a directly connected generator can be overcome by creating an interlocked earth fault protection scheme as illustrated in Figure 26 3 5 Pole slipping protection A generator might pole slip or fall out of step with other power system sources in the event of failed or abnormally weak excitation or as a result of delayed system fau
405. the operating time characteristic is changed from a load characteristic to a fault characteristic when the voltage drops below the set level W ith voltage restrained overcurrent when the voltage falls below a set value the current pick up level is proportionally lowered producing an infinite number of curves For generators that are connected to the system via a Delta Star transformer a Yd voltage correction is selectable within the relay Enable the 51V O vercurrent protection only If necessary change the scheme logic input matrix so that only the 51V will cause the output relays to operate There is no need to change the input matrix for blocking by the Voltage Balance element M easurement checks Inject rated volts into the V input terminals B25 B26 Record and check the voltage injected and the value measured by the relay allowing 3 tolerance Repeat the test by injecting rated volts into the V input terminals B27 B28 Inject rated current into the input terminals A11 A12 Record and check the current injected and the value measured by the relay allowing 3 tolerance Repeat the test for the I input terminals A13 A14 and the input terminals A15 A16 The 51V has three operating functions of which only one will be used Use the appropriate section for the relevant test instructions Function Section Restraint 6 10 2 Controlled 6 10 3 Simple 6 10 4 Service M anual R5942C LG PG111 Chapter 8
406. the self monitoring function Service M anual R5942B LG PG 111 9 11 Chapter 4 Page 50 of 50 Cold and warm resets The LGPG111 makes a distinction between a cold reset power on reset and warm reset watchdog reset A cold reset is caused by applying power to the relay A warm reset is normally caused by watchdog operation The watchdog provides a self reset mechanism for the relay to attempt to recover from any runtime error The watchdog circuit consists of a mono stable which must receive a trigger every 50ms otherwise it will reset the relay s hardware Under healthy conditions the software will trigger the watchdog periodically within its time out period If the microprocessor or the software fails the trigger will not occur forcing the watchdog to time out and reset the relay Some self monitoring functions can also force the watchdog to time out to produce a warm reset W hen the relay resets the power on diagnostics will be executed If the diagnostics test is successful an event will be recorded indicating whether this is a cold ora warm reset A known pattern in the volatile RAM is used to distinguish between the two situations Failure of any major diagnostics test will lockout the relay The failures detected by self monitoring which will force a watchdog reset are as follows 1 RAM failure 2 EPROM failure 3 Analogue input module failure 4 Communication hardware failure Chapter 5 Hardware Descrip
407. time can be used to provide protection under such circumstances Integrating timer facility An integrating timer facility is provided for the low forward power reverse power and field failure functions This facility is in the form of a delayed drop off timer and a delayed pick up timer as illustrated in Figure 27 Time integration ensures that the relay will operate within its pre determined operating time This is true even if the measuring element is only intermittently picked up provided the interfault time is within the setting of the delayed drop off timer After the relay has operated the timers and hence the trip output are reset instantaneously by the measuring element Time integration is required for the power functions under reciprocating load conditions when the measuring element picks up briefly and periodically The same feature is also required by the field failure function during conditions such as pole slipping Service M anual R5942B LG PG111 Chapter 4 Page 35 of 50 lt t RESET lt RESET lt ___ _ _ gt lt __ _ Reset time 0 Figure 26 Timer hold facility Delayed drop off timer Delayed pick up timer M easuring element output Delayed drop off Timer output Delayed pick up Timer output Figure 27 Integrating timing facility 4 Scheme Logic 4 1 Basic principle The protection scheme for a generator set normally involves
408. ting the amount of current or voltage injected depends upon the relay s settings The test instructions specify the amount of current or voltage Service M anual R5942C LG PG111 Chapter 8 Page 14 of 66 to be injected in terms of a multiple of a setting 1 5xl gt means the current injected should be 1 5 times the value of the I gt setting Itis recommended you copy settings from the setting schedule to the test record calculate the amount of current or voltage to inject and then do the test This allows the service settings to be applied and the protection operation checked off against them Different tolerances for checking the relay s pick up and drop off values operating time and measurements are specified in the test instructions Allowance for the accuracy of the injection equipment instrumentation and supply stability are not included in these tolerances therefore a reasonable additional tolerance can be added at the discretion of the commissioning engineer Pick up and drop off points can be checked without external indication by monitoring a percentage time to rip value in the Protection O peration Summary Section of the relay s menu A reading of 0 indicates the element is not picked up or has dropped off A value other than 0 indicates the measuring element has picked up W hen the value reaches 100 the element s output operates The red Trip LED on the relay can be operated by one or more of the output relays The
409. tion Service M anual R5942B LG PG111 Chapter 5 Page 2 of 23 ISSUE CONTROL ENGINEERING DOUCUMENT NUMBER 50005 1701 105 Issue Date Author Changes AP February 1995 Richard Price Original BP June 1995 Dave Banham Minor Updates A July 1995 Dave Styles Banham Publicity B Feb 1996 R Price Hardware modifications for compliance to European Union EMC directive for model number issue letter D onwards Service M anual LG PG111 Contents 1 INTRO DUCTION Ze RELAY IDEN TIFIC ATIO N 2 1 M odel numbering 2 2 M odule numbering 2 3 Scheme numbering 2 4 M echanical layout numbering 3 RELAY DESCRIPTIO N 4 CASE DESCRIPTIO N 5 MODULE DESCRIPTIO N S 5 1 Power supply 5 2 Relay output 5 3 M icrocomputer amp serial communications 5 3 1 Microcomputer board 5 3 2 Serial communications board 5 4 Isolation module 5 4 1 K Bus connection 5 4 5 4 5 4 5 4 5 4 5 4 5 4 5 4 5 4 5 4 5 4 5 4 5 5 5 6 5 6 5 6 5 6 1 1 Connection method 1 2 Recommended cable 1 3 Cable termination 1 4 Cable polarity 1 5 Maximum cable length 1 6 Maximum devices per spur 1 7 RS232 IEC870 connection 1 8 Connection method 1 9 Earthing arrangements 1 10 Recommended cable 1 11 Cable length 1 12 Data rates Status input Analogue and status input 1 Analogue inputs 2 Status inputs 3 Calibration data storage 5 6 4 Connections R5942B Chapter 5 Page 3 of 23 oOo Oo N
410. tion Relay inoperative alarm Enter a bit pattern of 0000000000000001 into the Relay Test cell in the Test Functions Section and press the SET key Check the contact across terminals G1 G 3 opens and the contact across terminals G1 G5 closes Check the relay inoperative alarm is on if the contact is wired in the protection scheme Record the test result At the completion of the tests set the Scheme O utput cell to Enabled in the Auxiliary Functions Section The yellow O ut Of Service LED should turn off Service M anual R5942C LG PG 111 10 10 1 Chapter 8 Page 60 of 66 SCHEME LOGIC TESTS A number of tactics can be employed to check and prove the scheme logic settings Visual comparison of the settings against the setting schedule Use of the remote communications via a PC or have the relay print the scheme settings out to facilitate a comparison of the settings with the setting schedule Test the operation of the scheme logic The latter option is discussed here The LG PG111 allows the operation of the scheme logic to be tested without the need to trip protective elements Instead input events or scenarios to the scheme logic can be setup and the scheme s output response observed The tests can be carried out whilst the relay is in service and without operating any of the output contacts In order to carry out the scheme logic tests a thorough understanding of the scheme logic in the LG P
411. tion 2 6 the voltage dependent overcurrent protection function 51V is provided with a timer characteristic timer hold setting tRESET which can be used to ensure that the protection function will respond to cyclic overcurrent during pole slipping In a similar KCEG lo gt Foward start KCEG directional relays are required where backfeed from another power system source is possible otherwise non directional KCGG relays could be used Figure 26 Interlocked Stator Earth Fault Protection Function Service M anual R5942B LG PG111 Chapter 3 Page 66 of 75 manner some operators of small unmanned hydrogenerators have relied on the integrating action of induction disc overcurrent protection to ensure disconnection of a persistently slipping machine 3 5 2 Field failure protection function 40 Slightly faster pole slipping protection might be assured in many applications by appropriately applying the field failure protection function and associated scheme logic timers W here the power system source impedance is relatively small in relation to the impedance of a generator during pole slipping the electrical centre of slipping is likely to lie within the generator This would be behind the LGPG111 relaying point as defined by the location of the voltage transformer Such a situation is likely to exist Base MVA 15 MVA Xd 130 Xd 34 Xs 4 3 18 37kA at 11kV i Eg Es 2 8 gt max R Case 15 MVA GT a me 0
412. tion of an automatic voltage regulator and by the response of any speed dependent excitation source e g shaftdriven exciter It can be seen from the simple analysis of Figures 27 30 that the LGPG111 field failure protection function may respond to the variation in impedance seen during pole slipping for some applications However the impedance characteristic offset might have to be reduced to guarantee response for the theoretical lower range of dynamic generator impedance X The lack of the normally recommended characteristic offset should not pose any problem of unwanted protection function response during the normal range of operation of a machine with rotor angles kept below 90 buta longer trip time delay might be required to prevent unwanted protection response during stable power swings caused by system disturbances The Base MVA 15 MVA Xd 130 Xd 34 Xs 4 3 18 37kA at 11kV FEg Es 2 8 gt max j R a Eg Es 1 2 Eg Es 1 0 Diameter Xd Case 15 MVA GT Condition Xg Xd t Eg Es 0 19 lt min Figure 28 Field failure protection function characteristics Small co generator most marginal condition to detect is where the generator is fully loaded with maximum excitation applied Even if the impedance characteristic offset is not reduced impedance element pick up should still occur during part of a slip cycle when the machine impedance is high and where the rotor angle is high More careful
413. tire memory device The Service M anual LG PG111 R5942B Chapter 6 Page 88 of 91 segmentation of the data into blocks follows the organisation of the data in the menu system M ost of the errors listed in Table 51 are not catastrophically detrimental as they affect only limited portions of the protection The loss of the scheme logic settings is however catastrophic to the protection The two failure modes are summarised in Table 50 Non Fatal Data Loss Fatal Data Loss Power Data is replaced by default values For Data is replaced by default values on protection setting data this disables the The relay runs normally but all failure protection protection operations are suspended The LGPG111 runs normally e Out Of Service LED is on e Relay Healthy LED is off Run time No effect on the LGPG111 s performance No effecton the LGPG111 s failure which continues normally performance which continues The error will continue to be asserted until new settings are entered or the relay is reset normally The error will continue to be asserted until new settings are entered or the relay is reset Table 50 Failure modes for loss of non volatile memory data Display Data corrupted in continued Input Label setting area System Data setting area Aux
414. to current transformer Q R Resistance of any other protective relays sharing the current transformer Q Service M anual R5942B LG PG111 Chapter 3 5 3 2 N ote 5 4 5 5 Page 73 of 75 For class X current transformers the excitation current at the calculated kneepoint voltage requirement should be less than 0 31 For IEC standard protection class current transformers it should be ensured that class 5P are used Core balanced current transformers Unlike a line current transformer the rated primary current for a core balanced current transformer may not be equal to the stator winding rated current This has been taken into account in the formula V gt O6ONI R 2R R W here V Minimum current transformer kneepoint voltage for through fault sta bility Maximum earth fault current N Core balanced current transformer rated primary current Relay rated current Resistance of current transformer secondary winding Q esistance of a single lead from relay to current transformer Q R R R esistance of any other protective relays sharing the current transformer Q ct L ZR ZR N should not be greater than 2 since 21 is the maximum measurable secondary cur rent The core balance current transformer ratio should be selected accordingly Stator earth fault protection function and sensitive directional earth fault current polarising input The earth path current input is used by the stator e
415. to detect earth faults over 95 of the stator windings Sensitive directional earth fault protection function is a method of assuring proper earth fault protection discrimination In cases where a generator might be earthed non directional or non unit earth fault Service M anual R5942B LG PG111 Chapter 3 Page 27 of 75 protection may not be able to distinguish between a fault on a generator fed from another earthed source and a fault on a parallel generator or the power system which may be fed by the protected generator W here earthing is provided by another power system source or by a bus earthing transformer a generator might never be earthed itself and so the generator might not be able to contribute zero sequence current to a system earth fault W ith such an arrangement there would still be a risk of incorrect non directional protection operation in the event of transient CT spill current This transient spill current might arise due to asymmetric CT saturation while passing offset current waveforms to an external phase fault or magnetising inrush current to a transformer being energised from the generator bus By setting the required residual polarising voltage threshold setting Vep gt high enough when applying the sensitive directional earth fault protection function 67N the problem of unwanted operation for external phase faults or in the presence of transformer magnetising inrush current can be eliminated W here the gener
416. to generators which are resistively earthed and is connected to the earth path CT to measure the neutral earth current Low set and high set elements are provided The low set element can either be set to a standard inverse curve or to a definite time characteristic The high set element consists of a definite time characteristic which can be set to instantaneous Enable the 51N Stator Earth Fault protection only Disable the 51N gt gt High Set element If necessary change the scheme logic input matrix so that only the 51N gt will cause the output relays to operate N ote the I inputis designed to measure small amounts of current to achieve this sensitivity the range is limited and the input will swamp at approximately 2 5 x rated current i e any current greater than 2 5 x rated current at this input will be measured and displayed as 2 5 x rated current M easurement checks Inject rated current into the input terminals A5 A6 Record and check the current injected and measured by the relay allowing 3 tolerance Characteristic and operating time for 51N gt Record the stator earth fault protection settings le gt t gt or TMS tRESET and the timer characteristic M easurement of le gt Inject 0 8 x le gt Amps into the input terminals A5 A6 and slowly increase the current to check the 51N gt pick up value Decrease the current to check the drop off value As there is a time delay associated with this
417. too slow to prevent the onset of damage so there may be a requirement for automatic generator disconnection or for an alarm to be raised For unattended generation plant e g small hydro schemes that are only periodically supervised automatic generator disconnection should occur even if immediate prime mover damage would not be envisaged If automatic disconnection did not occur in such cases motoring may be possible for hours with plant damage being gradually inflicted Automatic disconnection would also prevent an unnecessary power system loss In many cases prime mover failure can be detected by non electrical means e g by a steam turbine differential pressure switch or by a hydraulic flow device If mechanical means of detecting prime mover failure are provided an electrical measurement method would not be required or would only be used for backup detection Prime mover failure can be detected electrically by sensitive reverse power protection Service M anual R5942B LG PG111 Chapter 3 Page 37 of 75 This protection can be offered on a single phase basis for detection of balanced reverse power flow It can be seen from the above typical levels of reverse power flow thata very sensitive power element setting P gt would be required to detect prime mover failure in some applications The setting of the power element in secondary single phase W atts P gt should be less than 50 of the secondary motoring power as determined below
418. toring of the generator Reverse power is a balanced condition and therefore single phase measurement of the condition is sufficient The relay calculates Vicos from the A phase inputs In order to provide the required sensitivity a separate Current input is used A compensation angle setting is provided to allow for phasing errors of the generators CT s and VT s Service M anual R5942C LG PG 111 7 2 1 7 2 2 Chapter 8 Page 24 of 66 Enable the 32R Reverse Power protection only If necessary change the scheme logic input matrix so that only the 32R function will cause the output relays to operate There is no need to change the input matrix for blocking by the Voltage Balance element M easurements The 32R Reverse Power uses and Vap to calculate the active power in the A phase As there is no inputforV the relay calculates V from the V input by dividing by V3 and rotating by 30 Inject rated voltage into the V input terminals B25 B26 and rated current into the sensitive NPUt terminals A9 A10 Adjust the phase difference between the volts and the current so that sive 1S leading V by 150 the relay should display the phase angle in the measurements section as 180 Record and check the current voltage phase angle and active power measured by the relay allowing 3 tolerance for measured current and voltage The measured active power should be 4xV V3 Watts allowing 5 tolerance where V and
419. ts and outputs to be given appropriate identifier labels 17 1 Input labels A sub title cell for the remote system only all the input label settings are indented below this 17 2 to 17 9 Input label settings Eight 15 character labels for the scheme definable optically isolated logic inputs These settings are password protected 17 10 O utput labels A sub title cell for the remote system only all the output label settings are indented below this 17 11 to 17 25 Output label settings Fifteen 16 character labels for the scheme logic definable output contacts These settings are password protected The 16th available character position is reserved for the minus prefix used to indicate negated inputs Service M anual R5942B LG PG111 Chapter 6 Page 65 of 91 7 19 Remote communications Item Front Panel 2 Remote Access 18 0 REMOTE Remote Communications COMMUNICATIONS 18 1 Relay Address Relay Address 1 1 18 2 Remote Setting Remote Setting Enabled Enabled 18 3 Comms Mode Communications Mode Rear IEC870 FT1 2 Rear IEC870FT1 2 18 4 Minimum Transmit Minimum Transmit Delay Os Delay Os 118 5 Baud Rate Serial Baud Rate 19200 19200 j Table 40 The LG PG111 s Remote Communications Section of its menu Configuration settings for the remote access user interface The remote system
420. tting to compensate for any phase errors and this is accounted for in these measurements 4 15 Frequency The measured power system frequency Service M anual R5942B LG PG 111 Chapter 6 Page 40 of 91 7 6 MEASUREMENTS 2 Item Front Panel Remote Access pa a 5 0 MEASUREMENTS 2 Measurements 2 5 1 16 Aug 1994 16 02 58 218 5 2 Ia Diff Ia Diff OA OA 5 3 Ib Diff Ib Diff OA OA 5 4 Ic Diff Ic Diff OA OA 5 5 Ia Bias Ia Bias OA OA 5 6 Ib Bias Ib Bias OA OA 5 7 Ic Bias Ic Bias OA OA 5 8 Ia Mean Bias Ia Mean Bias OA OA 5 9 Ib Mean Bias Ib Mean Bias OA OA 5 10 Ic Mean Bias Ic Mean Bias OA OA 5 11 Ta Sensitive Ia Sensitive OA a 5 12 Vab Comp Vab Comp OV OV oo 5 13 Vbc Comp Vbc Comp OV OV Ie 3 5 14 Tracking Input Tracking Input No Signal No Signal Table 16 The LGPG111 s Measurements 2 Section of its menu 5 1 5 2 5 3 This section complements the M easurements 1 section by providing all the other measurements the LG PG 111 is making All magnitude values for the voltages and currents are rms values of the measured fundamental all harmonic components have been removed by signal processing Date amp time This cell only appears on the remote access menu W hen the remote system reads this section it captures a snapshot of the measurement values this cell provides a time stamp indicating when the
421. ttings in this mode of operation The RESETkey enters this mode and allows the section titles to be stepped through The ACCEPT READ key then selects the displayed section and allows the contents of the section to be stepped through Pressing the RESET key inside a section returns Service M anual R5942B LG PG111 Chapter 6 Page 12 of 91 the display to the next section title Both the title and content stepping wrap around with the title wrap around including the default display W ith the relay s front cover removed a further ancillary key action is possible The lt arrow key aborts the menu scan and returns the menu to its default display This key action is included principally as a quick way back to the default display when the relay is being demonstrated Menu Contents Section Contents SYSTEM DATA RESET AUXILIARY ACCEPT Date 1994 Jan 01 FUNCTIONS READ Time 00 00 03 ACCEPT READ Logic I P Status 00000000000000 ACCEPT READ Relay O P Status 0000000000000000 ACCEPT READ This cell s binary value is displayed on the next press of ACCEPT READ Protection ACCEPT READ 0000 0000000000000010 ACCEPT READ Relay Alarms Not Present TRANS FORME RATIOS RESET RESET Figure 7 Example of the front panel menu scan procedure Service M anual R5942B LG PG111 Chapter 6 4 3 3 Page 13 of 91 Menu browse The
422. ual R5942B LG PG111 Chapter 4 Page 30 of 50 Figure 19 Field failure characteristic The technique to determine whether the impedance measured by the relay is inside the mho characteristic on the impedance plane is illustrated in Figure 20 If Zr is the impedance measured it can be seen that from Figure 20 a Z will be inside the mho circle if the phase angle between 7 x4 and Zg X2 S greater than 90 By multiplying the impedance with the current la the mho characteristic can be represented as shown in Figure 20 b The criterion for operation now becomes L V 1 xX 2 V 1 x X gt 90 This can be transformed into a cosine inequality below which can be expanded into terms of Fourier sine and cosine vector components and computed accordingly cof Z V 1 xX Z V 1 xX lt 0 For the field failure function X1 jXa and X2 4 Xa Xb No trip a Impedance diagram b Equivalent vector diagram for implementation Figure 20 Implementation of the field failure mho characteristic Service M anual R5942B LG PG111 Chapter 4 3 9 3 9 1 Page 31 of 50 Under and over voltage 27 amp 59 The LGPG111 provides an under voltage function and a two stage over voltage function The input quantities are V and V The quantity V is calculated from V and V vectorially Va Va Vee Both functions are three phase devices All individual phase elements must ope
423. ue characteristic when operating in the induction generator mode if the initial output of the generator was nota high percentage of its rated capability or if the governor and prime mover have a very fast response In such a case stable operation as an induction generator might be achieved at low slip 0 1 0 2 above synchronous speed The machine would be able to maintain an active power output perhaps 20 30 of rating whilst drawing reactive power from the power system generating ata highly leading power factor The ability to reach such a stabilised state will be dependent on the machine s effective speed torque characteristic when operating as an induction generator and on the power system being able to supply the required reactive power without severe voltage depression Salientpole generators can operate particularly well as induction generators up to a significant percentage of rated power output 20 30 P_ This is due to the significant difference between the direct and quadrature axis synchronous reactance s Cylindrical rotor machines have similar direct and quadrature synchronous reactance s and are less able to deliver a significant power output as an induction generator They are more likely to be pushed over the peak torque level of their induction generator speed torque characteristic when driven at only a small percentage of rated power output If the peak induction generator torque level is exceeded a machine will stabilise
424. ularly useful for large sections such as the scheme logic and for settings with a wide setting range such as the transformer ratios Since the display updates on each key press including each auto repeat press the display always reflects the current selection and hence provides a visual feed back as to the state of the auto repeated selection The front panel s display is used to present the relay s internal menu and in combination with the key buttons facilitates user interaction with the relay The menu is organised in a tree structure under the default display as illustrated in Figure 5 Default display The default display represents the root of the LG PG111 s menu system and itis from this display that one of the three modes of operation described in the following section can be entered The default display consists of a selectble primary display and several over ride displays The over ride displays replace the primary display when the LGPG111 has a warning to report The primary default displays are user selectble from the following GENERATOR J i PROTECTION e inti Description oan LGPGl11 Relay Model Number ee LGPG11101S533LEA e Plant Reference Plant Reference ee e Phase Currents 0 68 A 0 69 A ln iB 0 67 A c e line Voltages ALOT Ve 110 V VAB Vec 110 V Vea iti Ie 0 034 A Earth Quantities aa e Negative Phase Sequence 12 158
425. ule should be placed in an electrically conducting anti static bag There are no setting adjustments within the modules and itis advised that itis not unnecessarily disassembled Although the printed circuit boards are plugged together the connectors are a manufacturing aid and not intended for frequent dismantling in fact considerable effort may be required to separate them Touching the printed circuit boards should be avoided since complementary metal oxide semiconductors CMOS are used which can be damaged by static electricity discharged from the body HANDLING OF ELECTRONIC EQUIPMENT A person s normal movements can easily generate electrostatic potentials of several thousand volts Discharge of these voltages into semiconductor devices when handling electronic circuits can cause serious damage which often may not be immediately apparent but the reliability of the circuit will have been reduced The electronic circuits are completely safe from electrostatic discharge when housed in the case Do not expose them to risk of damage by withdrawing modules unnecessarily Each module incorporates the highest practicable protection for its semiconductor devices However if it becomes necessary to withdraw a module the following precautions below should be taken to preserve the high reliability and long life for which the equipment has been designed and manufactured 1 Before removing a module ensure that you are atthe same electrostat
426. umerical techniques The analogue signals are converted into digital data using an analogue to digital conversion circuit The data is processed by a powerful 16 bit microprocessor which performs digital signal processing and executes various protection algorithms The LGPG111 implements a user configurable scheme logic The scheme logic monitors the states of the protection functions and logic inputs and controls the relay outputs through logic functions The scheme logic because it is software based is integrated into the relay at minimum extra cost and can be reconfigured easily by changing relay settings Three types of recording facilities are available event fault and disturbance recording An event record logs the operation of the protection functions energisation of logic inputs or relay outputs or any internal relay failure A fault record is essentially an event record with additional measurement values recorded at the time of fault The disturbance recorder captures data from 8 analogue channels together with states of all the logic inputs and relay outputs over a period The LGPG111 provides two user interfaces one is situated on the relay s front panel and the other consists of a remote serial interface Both interfaces access a common internal menu database The database consists of the relay settings measurements and recordings Some of this information can also be printed out through the parallel port to a printer
427. unction operates from signals derived from the relay s two main VT inputs and signals derived from an additional pair of reference VT inputs The level of voltage difference is determined between each of the two main and reference voltage inputs W hen a voltage difference in excess of an adjustable threshold Vs is detected an alarm is raised The failed VT circuit is identified by comparing the voltage inputs to see which has the lower voltage level W here a generator is provided with two sets of terminal VT s the set used for the generator protection functions should be connected to the main relay inputs and the other set should be connected to the reference inputs W ith this arrangement the voltage balance protection function will be able to respond to blown VT secondary fuses and possibly to blown VTprimary fuses W here a three phase threelimb VT is used the VT primary winding star point should not be earthed if detection of blown primary fuses is a requirement An alarm and failed VT indication will be raised if either set of VT signals fails If the main VT signals fail blocking of voltage sensitive protection functions can be arranged via the LGPG111 flexible scheme logic matrix see Figure 20 W here only one generator terminal VT is provided the VT secondary windings should Service M anual R5942B LG PG111 Chapter 3 Page 58 of 75 be connected to two separately fused secondary circuits O ne circuit should only be connected
428. up to 3 can be introduced 2 Phase error due to sampling delay between channels A sampling delay of 20us is introduced between channels to allow time for data acquisition This produces a phase error of 0 36 at50Hz 0 43 at60 Hz between channels Such an angular error although small can introduce significant errors in those functions where phase accuracy is important such as negative phase sequence and power functions 3 Frequency response of the analogue input circuitry Since the LGPG111 hasa wide frequency operating range the frequency response of the input transducers and the low pass filters will affect the accuracy of the relay over the range The first two types of error are compensated using a software calibration procedure during production In phase voltage and current signals of specified magnitudes are applied to the relay inputs W ith the relay in a special calibration mode it samples the input signals and stores the data into disturbance records The records are uploaded into a PC which computes the magnitude and phase errors produced by the relay s measurement elements These errors are transformed into compensation vectors which are stored in the non volatile memory in the Analogue and Status Input Module By multiplying the measured vector components of each signal with a corresponding compensation vector the relay is able to compensate for both the component tolerance and the sampling delay Comparing with har
429. urrent pick up level for the voltage restrained function is 1 I gt for V gt Vs1 2 kispe Eey vs2 for Vs2 lt V lt Vs1 KI gt 4V 0 lt V lt Vsl Vs2 3 Ks for V lt Vs2 Current Current Pick up Pick up Level Level gt gt Vsl Voltage Level Voltage controlled mode Voltage restrained mode Figure 14 Voltage dependent overcurrent pick up characteristic The standard inverse characteristic is 14 t TMS x seconds I gt 1 Since the ADC saturates for currents above 20 48xln the inverse timing characteristic is a composite as illustrated in Figure 15 Voltage vector transformation If a generator is connected to a busbar through a delta star step up transformer a solid phase to phase fault on the busbar will only result in partial phase to phase voltage collapse at the generator terminals The voltage dependent overcurrent func tion 51V may not be sensitive enough to detect such faults O n the other hand a Service M anual R5942B LG PG111 Chapter 4 Page 24 of 50 phase to earth fault on the HV side would yield a low phase to phase voltage on the delta side and the 51V may respond inappropriately Such faults should be dealt with by the HV standby earth fault protection In order for the voltage dependent overcurrent function to co ordinate correctly with other relays on the system where there is a delta star step up transformer an internal voltage vector transformation feature
430. used to determine the point at which this function starts to operate The Protection O peration Summary should indicate 0 when the Current injected is increased to the pick up point the displayed percentage will start to increase this is the pick up point the displayed value will rise from 0 and displays 100 when the time delay has expired Accept and reset all alarms pick up value I gt setting with a 5 tolerance drop off value 0 95xI gt setting with a 5 tolerance Repeat the tests for phases B and C M easurement of K I gt point 2 For the different voltage vector rotation setting inject the voltage as follows for each phase Voltage Phase A Phase B Phase C Rotation Inject Inject Inject Setting None K I gt into l 0 5xVs2 K I gt into Ip 0 5xVs2 K I gt into Ic 0 5xVs2 into Vab into Vic into Veca Yd K I gt into l 0 5xVs2 K I gt into Ip 0 5xVs2 K I gt into I 0 5xVs2 into Vab into Vap into Vc Inject the specified current and voltage to check the pick up and drop off values The Protection O peration Summary Section of the relay s menu can be used to determine this without the need to wait for timer operation Accept and reset all alarms pick up value K gt setting with a 5 tolerance drop off value 0 95xK I gt setting with a 5 tolerance Repeat the tests for phases B and C Measurement at 50 of curve point
431. ve setting group enabled the two setting groups are shown as pairs of sections see Figure 3 one for each group and one pair for every section of the protection and scheme logic The group number is included in the section s title and for the front panel interface itis included in every cell within the section Service M anual R5942B LGPG111 Chapter 6 4 1 Page 7 of 91 If the application for the LG PG 111 does not require the use of an alternative setting group it may be turned off In this case all references to multiple setting groups are removed from the menu and the alternative group hidden If group 2 was selected when this happens group 1 settings are re selected Differential C System data Enabled Measurements Is1 0 05A Records K1 0 Differential 1 Is2 1 2A Differential 2 K2 Earth fault 1 Earth fault 2 Figure 3 An illustration of the menu system with the alternative setting group enabled FRONT PANEL USER INTERFACE Description The front panel user interface consists of a liquid crystal display LCD seven push buttons and 4 light emitting diodes LED s There is also a non isolated serial port for connection to a PC and a parallel port for connection to a Centronics type parallel printer aur PROTECTION ourorsewice LGPG111 C RELAY HEALTHY ACCEPT READ PARALLEL SERIAL
432. vely this protection function could be driven from a CT on the earthing transformer secondary Figure 5 Protection of an indirectly connected generator for parallel operation Service M anual R5942B LG PG111 Chapter 3 Page 16 of 75 To To transtormer step up differential transtormer protection ABC nabc E oii ea Cll a Him Un or pct Pan mt aa Bis Comparison V T _residual A7 i SS f p la KUNA l te ai Ib a ia Ic 2S C y la Bel AJ lb_bias ve PEE A20 A af ITa S Figure 6 LGPG 111 connections for indirectly connected generator for parallel operation The most likely mode of stator winding insulation failure will be between a winding conductor and the stator core resulting in a stator earth fault Such a fault would be detected by the generator differential protection if the currentis high enough To further limit stator winding fault damage the stator windings of generators are Service M anual R5942B LG PG111 Chapter 3 Page 17 of 75 commonly earthed through an impedance to limit stator earth fault currents see Section 2 3 In the case of very high impedance earthing the stator generator differential protection will only respond to a phase phase fault or an earth fault with the earthing impedance short circuited A phase phase fault is most likely to occur within the machine connections The probability of such a fault occurring would be dependent on the way in
433. vercurrent timers when energised The logic is shown in Figure 13 51V Inhibit Input S 51V gt Trip Figure 13 The 51V Inhibit input to reset the overcurrent timers Settings and protection characteristic The settings provided by this function are as follows Function Selection for voltage restrained voltage controlled or simple overcurrent Voltage vector Rotate Selection for either N one i e no vector rotation or Yd i e vector rotation for delta star step up transformer Vsl First voltage threshold setting for voltage restrained overcurrent Vs2 Second voltage threshold setting for voltage restrained overcurrent Vs Voltage threshold setting for voltage controlled overcurrent Service M anual R5942B LG PG111 Chapter 4 Page 23 of 50 K Constant for the voltage controlled or restrained overcurrent Characteristic Selection for either standard inverse or definite time characteristic I gt Overcurrent threshold setting t Definite time setting if definite time characteristic is selected TMS Timer multiplier setting if standard inverse is selected tRESET Reset timer setting for the timer hold facility 3 5 3 The effect of the voltage level on the current pick up level for both operating modes is as follows The characteristics are illustrated in Figure 14 The current pick up level for the voltage controlled function is 1 1 gt for V gt Vs 2 K l gt forV lt Vs The c
434. visable to compare the pin assignments of the serial ports on the LG PG 111 with those of the equipment to be connected The receive and transmit pins are interchanged between the front port and rear port pin assignments If the LGPG111 detects any problems with the communications hardware it will raise an alarm log the event and attempt to restore communications by forcing a watchdog reset once only If the failure is still evident the communications will be disabled and an alarm raised O ther aspects of the LGPG111 are not affected by this failure Service M anual R5942C LG PG 111 4 4 1 4 2 4 3 4 3 1 4 3 2 4 3 3 4 4 4 5 4 5 1 4 5 2 Chapter 7 Page 10 of 14 PROBLEM SOLVING Password lost or not accepted If the LG PG 111 will not accept its password itis a probably because the password has been inadvertently changed in the relay The password lock in the LGPG111 can be unlocked with a backup password obtainable from ALSTOM T amp D Protection amp Control Limited or our nearest authorised representative Please supply the relay s full model number and serial number These must be the numbers reported in the System Data section of the menu Relay tripping Relay does not operate when protection has operated 1 Scheme logic and or protection settings incorrect possibly due to a non volatile EEPROM error and default settings have been restored 2 Relay is out of service OUT OF S
435. voltage into the V input terminals B25 B26 and rated current into the input terminals A9 A10 Adjust the phase difference between the applied volts sensitive Service M anual R5942C LG PG 111 1 3 2 Chapter 8 Page 26 of 66 and current so that iS lagging V by 30 a unity power factor for A phase Record and check the current voltage phase angle and active power measured by the relay allowing 3 tolerance for measured current and voltage The measured active power should be 4xV V3 Watts allowing 5 tolerance where V and are injected voltage and current respectively The phase angle between I sensitive and V measured on the relay should be 0 degrees with a tolerance of 5 Stop the current injection Reset all alarms Alternatively if the available test equipment cannot provide a phase shift inject rated volts into B25 B26 ata 0 phase angle and rated currentinto A9 A10 ata 0 phase angle The phase angle now measured by the relay should read 30 The measured active power should be 1x V x cos30 V3 Watts allowing 5 tolerance where V and are injected voltage and current respectively and cos30 0 866 Characteristic and operating time Record the reverse power protection settings P tand tDO Set the phase difference between the applied volts and current so that l oie IS lagging V by 30 inject1 1 x the expected pick up currentinto the b sensitive input terminals A9 A10 and
436. voltage protection functions plus a voltage balance or VT fuse failure function 13 1 Under voltage status The protection function can either be enabled or disabled The setting is password protected 13 2 amp 13 3 Under voltage settings 13 4 Over voltage status The protection function can either be enabled or disabled The setting is password protected 13 5 13 6 13 7 amp 13 8 Over voltage settings The over voltage protection function consists of two elements a low set V gt and a high set V gt gt 13 9 Voltage balance status The protection function can either be enabled or disabled The setting is password protected 13 10 Voltage balance setting Service M anual R5942B LG PG111 Chapter 6 Page 59 of 91 7 15 Negative phase sequence Item Front Panel Remote Access aed 14 0 NEGATIVE PHASE Negative Phase Sequenc SEQUENCE 114 1 46 Neg Phase Seq 46 N gative Phase Sequence Enabled Enabled 14 2 46 gt gt NPS Thermal Trip 114 3 46 gt gt NPS Trip I2 gt gt 0 05 A I2 gt gt 0 05 A 14 4 46 gt gt NPS Trip K 2 9 K 28 Mae 14 5 46 gt gt NPS Trip TMAX 500 s tMAX 500 s 114 6 46 gt gt NPS Trip tMIN 1 00 s tMIN 1 00 s 14 7 46 gt gt NPS Trip Kreset 2s Kreset 2 s 14 8 46 gt NPS Alarm 14 9 46 gt NPS Alarm 12 gt 0 03 A I2 gt 0 03 A ag 14 10 46 gt NPS Ala
437. y The 19 5V rails are regulated on the analogue and status input board to 15V for analogue circuitry or to 12V for RS232 factory test interface on the microcomputer board The 24V rail is used unregulated to switch the output relays An under voltage monitoring circuit is employed within the power supply module If the voltage on any rail is out of tolerance a power supply fail signal is asserted on the I O bus to disable the relay An alarm output relay inside the power supply module is also de energised The alarm output relay has one normally open contact and one normally closed contact which are brought out to the MIDOS connector The terminal allocation of the power supply module is shown in Table 5 Also see the LG PG111 external connection diagram for specific connection details Power Supply Failure Alarm normally open Power Supply Failure Alarm normally closed 13 Vx 1 auxiliary DC input Table 5 Terminal allocation of the power supply module Service M anual R5942B LG PG111 Chapter 5 5 2 Page 9 of 23 Relay output Module N umber GM0032 Two relay output modules are fitted in the LGPG111 Each module has eight PCB mounted miniature hinged armature relays The rating of these relays is given in Table 6 Two change over and eleven normally open contacts are wired to a 28 way MIDOS connector for external connection see Table 7 Make and Carry 7500VA for 0 2s with maixima of 30A
438. y the relay allowing 0 5 Hz tolerance Service M anual R5942C LG PG 111 6 2 5 6 3 6 3 1 6 3 2 Chapter 8 Page 20 of 66 Fault record checks Use the front panel keys to navigate to the menu section View Records and ensure that the records match the injected faults carried out above Power based protection The following instructions are for the testing the functions that are based on power measurement The functions that use power measurement are 32R Reverse power and 32L Low forward power M easurement of phase angle The 32L Low Forward Power uses and Vap to calculate the active power in the A phase As there is no input for V the relay calculates it from the V input by dividing by V3 and rotating by 30 Inject rated volts into the V input terminals B25 B26 ata 0 phase angle and rated current into the input terminals A9 A10 ata 0 phase angle The phase angle measured by the relay should read 30 The measured active power should be Ix V x cos30 V3 Watts allowing a 5 tolerance where V and are injected voltage and current respectively and cos30 0 866 M easurement of Directional Boundary Enable the 67N Sensitive Directional Earth Fault protection only If necessary change the scheme logic input matrix so that only the 67N will cause the output relays to operate Seta value for the characteristic angle RCA Inject 20V into the V input terminals B19 B20 and rat

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