Service Manual Type MYTU 04 Field Failure Relay
Contents
1. 4 1 2 Visual inspection 4 1 5 Insulation tests 4 2 2 Auxiliary supply measured on terminals 17 amp 18 V Relay CT shorting facility checked 4 2 3 Test feature satisfactory 2 4 2 5 4 2 6 4 2 7 4 2 8 4 2 9 Relay Z2 setting Q Measured Z2 boundary A V Z Z2 Q Z2 Q v l With I reduced 10 relay drops off Characteristic angle check 01 measured 02 measured characteristic angle lead Relay Z1 setting Q Measured Z1 boundary A V V Z he 21 Timing tests Set time S Measured time s Reset time ms System load check Angle between VAB and IA Wimmer ie Angle between VAB and IB nn Commissioning Engineer Customer Witness Date Date 22 REPAIR FORM Please complete this form and return it to ALSTOM T amp D Protection amp Control Ltd with the equipment to be repaired This form may also be used in the case of application queries ALSTOM T amp D Protection amp Control Ltd St Leonards Works Stafford ST17 ALX England For After Sales Service Department Customer Ref Model No Contract Ref Serial No Date 1 What parameters were in use at the time the fault occurred AC volts Main VT Test set DC volts Battery Power supply AC current Main CT Test set Frequency 2 Which type of test was being used 3 Were all the external components fitted where required Yes No Delete as approp2. Auxiliary supply The auxiliary supply should be checked at terminals 13 if dc and 14 with the module removed If a test block type MMLG is fitted the auxiliary supply may be routed through it If the auxiliary supply is ac it should be checked at terminals 15 and 16 Removal of the cover provides isolation of one connection If the test plug type MMLBO1 is to be used the links to provide CT shorting must be in place before it is inserted The CT shorting facility in the relay case should be checked with the relay removed Links can then be put on the test plug to restore auxiliary supplies to the relay The scheme connection diagram must be referred to 12 4 2 3 4 2 4 4 2 5 4 2 6 For supplies greater than 125V dc an external resistor can be used giving about 110V dc at the relay For 24 30V dc supplies an MSTZ 02 is used in conjunction with a 48V relay Test feature Set the time delay setting to about 1 second or the lowest available setting if higher than 1 second Check that pressing the test push button causes the trip LED to light after the set time Set the time delay to the minimum setting Secondary injection connections The relay should now be connected to the test circuit as shown in Figure 3 taking care to note the correct connections of the phase angle meter It should be noted that the relay has a characteristic as given in Figure 1 in terms of system primary impedances The required impedance se
3. 2 If a test block type MMLG is 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 and with odd terminal numbers 1 3 5 7 etc The auxiliary supply volts to the scheme are normally routed via test block terminals 13 and 15 Earthing Ensure that the case earthing connection above the rear terminal block is connected to the local earth bar Insulation tests These tests may be done by the main plant contractor at an earlier date The relay and its associated wiring may be insulation tested between all electrically isolated circuits all circuits and earth An electronic or brushless insulation tester should be used giving a dc voltage not exceeding 1000V Accessible terminals of the same circuit should first be strapped together Deliberate circuit earthing links removed for the tests must subsequently be replaced Commissioning tests Equipment required 1 Double pole switch 1 Time interval meter 2 Variacs 1 suitable for 2x relay rated current 1 Phase shifter giving 100 to 200V on the secondary side 1 Phase angle meter able to respond to currents from 0 2 to 2x rated current 1 Voltmeter 1 Ammeter Variable resistor suitable for 2x rated current About 1000 for 1A relay or 200 for 5A relay Note For 5A relays a CT could be used to step up the current with a 100Q 2A rated resistor being used
4. Supply ZO gt 440 110 Volt phase shifter AO LH Current control resistance nos 2 10 A Interposing CT option for 5A relays 18 17 26 2325 24 Rated dc or ac A Ammeter auxiliary supply V Voltmeter PA Phase angle meter MYTU This variac could be used to step up the voltage for relays with Vn 220V or 380V 50 Vn is satisfactory for tests Figure3 Circuit diagram for secondary injection tests 18 en Phase angle meter gt 24 MYTU 04 RELAY l i 23 26 Figure 4 Circuit diagram for system load checks MYTU TRIP Figure 5 Chart of in service settings 20 Section 7 COMMISSIONING TEST RECORD Station Circuit Relay Model No Serial No Auxiliary Supply Vx V AC DC Rated Current A 50Hz 60Hz VT ratio CT ratio Machine transient reactance Xd Machine synchronous reactance Xs 3 1 Required relay characteristics i For rotor angles up to 90 and no leading power factors Offset x Circle diameter Xs ii For rotor angles up to 120 and leading power factors Offset Circle diameter Calculated required relay secondary impedance settings 3 2 Offset Z1 Q 3 3 Circle diameter setting Z2 Q Outer impedance Q Chart of in service settings filled in Commissioning tests
5. in timer enables the relay to be co ordinated with other devices and to avoid the possibility of maloperation on synchronisation surges One changeover contact and one normally open contact are available with the set time delay An LED provides indication of operation of the time delayed contacts Pressing a test button causes the LED to light after the set time delay No contacts should operate The contacts are self reset and the LED is made to reset via a push button Section 2 INSTALLATION 2 1 2 2 2 3 2 4 2 5 Protective relays although generally of robust construction require careful treatment prior to installation and a wise selection of site By observing a few simple rules the possibility of premature failure is eliminated and a high degree of performance can be expected The relays are despatched either individually or as part of a panel rack mounted assembly in cartons specifically designed to protect them from damage Relays should be examined immediately they are received to ensure that no damage has been sustained in transit If damage due to rough handling is evident a claim should be made to the transport company concerned immediately and ALSTOM T amp D Protection amp Control should be promptly notified Relays which are supplied unmounted and not intended for immediate installation should be returned to their protective polythene bogs Care must be taken when unpacking and installing the relays so th
6. relay contacts should be removed before checking any mechanical settings to avoid any risk of electric shock Draw out case relays Removal of the cover on equipment incorporating electromechanical operating elements may expose hazardous live parts such as relay contacts Insertion and withdrawal of extender cards When using an extender card this should not be inserted or withdrawn from the equipment whilst it is energised This is to avoid possible shock or damage hazards Hazardous live voltages may be accessible on the extender card Insertion and withdrawal of heavy current test plugs When using a heavy current test plug CT shorting links must be in place before insertion or removal to avoid potentially lethal voltages Decommissioning and Disposal Decommissioning The auxiliary supply circuit in the relay may include capacitors across the supply or to earth To avoid electric shock or energy hazards after completely isolating the supplies to the relay both poles of any dc supply the capacitors should be safely discharged via the external terminals prior to decommissioning Disposal It is recommended that incineration and disposal to water courses is avoided The product should be disposed of in a safe manner Any products containing batteries should have them removed before disposal taking precautions to avoid short circuits Particular regulations within the country of operation may apply to the disposal of lithium ba
7. you are both at the same electrostatic potential Shaking hands achieves equipotential 4 Place the module on an antistatic surface or on a conducting surface which is at the 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 60147 0F If you are making measurements on the internal electronic circuitry of an equipment in service it is preferable that you are earthed to the case with a conductive wrist strap Wrist straps should have a resistance to ground between 500k 10MQ 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 out in a Special Handling Area such as described in BS5783 or IEC 60147 0F ALSTOM 4 2 9 CONTENTS SAFETY SECTION DESCRIPTION INSTALLATION APPLICATION AND SELECTION OF SETTINGS Typical relay settings Offset setting Circle diameter setting Time delay setting COMMISSIONING Commissioning preliminaries Electrostatic discharge Inspection Earthing Insulation tests Commissioning tests Equipment required Auxiliary supply S
8. 1000 100 Required circle diameter Xs 440 Select the nearest setting below ie set Z2 40Q unless the setting above is within 10 Time delay setting The relay is normally set to operate after a time delay t to avoid maloperation due to synchronous surges and transient conditions The time delay must also be shorter than the thermal limits of the rotor and stator windings A typical setting of approximately 5 seconds is normally applied This will vary with different applications depending on machine parameters and the nature of the external network Section 4 COMMISSIONING 4 1 4 1 1 4 1 2 4 1 3 Commissioning preliminaries Electrostatic discharge The relay uses components which are sensitive to electrostatic discharges When handling the withdrawn module care should be taken to avoid contact with components and electrical connections When removed from its case for storage the module should be placed in an electrically conducting anti static bag Inspection Carefully examine the module and case to see that no damage has occurred during transit Check that the relay serial number on the module case and cover are identical Also check that the rating information is correct for the system Wiring Check that the external wiring is correct to the relevant relay diagram and or scheme diagram The relay external connection diagram number is given on the rating label inside the case 11 4 2 4 2 1 4 2
9. at none of the parts are damaged or their settings altered and must only be handled by skilled persons Relays which 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 constructional work If relays are not installed immediately upon receipt they should be stored in a place free from dust and moisture in their original cartons and where 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 damp ambient conditions and may be restored by gently heating the bag for about an hour prior to replacing it in the carton Dust which collects on a carton may on subsequent unpacking find its way into the relay in damp conditions the carton and packing may become impregnated with moisture and the de humidifying agent will lose its efficiency The storage temperature range is 25 C to 70 C The installation should be clean dry and reasonably free from dust and excessive vibration The site should preferably be well illuminated to facilitate inspection An outline diagram is normally supplied showing panel cut outs and hole centres For individually mounted relays these dimensions will also be found in Publication R6115 Publication R7012 Parts Catalogue and Assembly Instructions will be usefu
10. econdary injection connections To check Z2 setting To check the relay characteristic angle RCA To check the Z1 setting Timing checks System load checks MAINTENANCE PROBLEM ANALYSIS COMMISSIONING TEST RECORD REPAIR FORM SAFETY SECTION This Safety Section should be read before commencing any work on the equipment Health and safety The information in the Safety Section of the product documentation is intended to ensure that products are properly installed and handled in order to maintain them in a safe condition It is assumed that everyone who will be associated with the equipment will be familiar with the contents of the Safety Section Explanation of symbols and labels The meaning of symbols and labels which may be used on the equipment or in the product documentation is given below A Caution refer to product documentation Caution risk of electric shock e gt Protective safety earth terminal imami Functional earth terminal Note this symbol may also be used for a protective safety earth terminal if that terminal is part of a terminal block or sub assembly eg power supply Note The term earth used throughout the product documentation is the direct equivalent of the North American term ground Installing Commissioning and Servicing Equipment connections Personnel undertaking installation commissioning or servicing work on this equipment should be aware of the correct working proc
11. edures to ensure safety The product documentation should be consulted before installing commissioning or servicing the equipment Terminals exposed during installation commissioning and maintenance may present a hazardous voltage unless the equipment is electrically isolated If there is unlocked access to the rear of the equipment care should be taken by all personnel to avoid electric shock or energy hazards Voltage and current connections should be made using insulated crimp terminations to ensure that terminal block insulation requirements are maintained for safety To ensure that wires are correctly terminated the correct crimp terminal and tool for the wire size should be used gt PP eee Before energising the equipment it must be earthed using the protective earth terminal or the appropriate termination of the supply plug in the case of plug connected equipment Omitting or disconnecting the equipment earth may cause a safety hazard The recommended minimum earth wire size is 2 5 mm2 unless otherwise stated in the technical data section of the product documentation Before energising the equipment the following should be checked Voltage rating and polarity CT circuit rating and integrity of connections Protective fuse rating Integrity of earth connection where applicable Equipment operating conditions The equipment should be operated within the specified electrical and environmental limits Current tra
12. he machine at rotor angles up to 120 the above settings are modified to three quarters of the machine transient reactance 3 Xd 4 for the offset and half the machine synchronous reactance Xs 2 for the circle diameter The following worked example indicates the method to be used in calculating the required relay settings The characteristics of the machine to be used are as follows Voltage 11kV 3 phase 50Hz Output 15 MVA 0 8 power factor Machine transient reactance Xd 19 Machine synchronous reactance 200 Current transformer ratio 1500 5 Voltage transformer ratio 11000 100 Typical relay settings i For rotor angles up to 90 and no leading power factors Offset Xd 2 Circle diameter Xs ii For rotor angles up to 120 and leading power factors Offset 3 Xd 4 Circle diameter Xs 2 Relay to be set for condition i above 10 3 2 3 3 3 4 Offset setting Machine transient reactance Xd in secondary is 19x 112 1500 5 x 4 80 100 x 15 11000 100 Required offset setting Xd 2 4 18 2 2 090 Relay setting Z1 represents the required offset setting This is set to the nearest available higher setting Alternotively the setting below can be used if this is within 10 of the required setting In this case the offset should be set to Z 2 00 Circle diameter setting Machine synchronous reactance Xs in secondary ohms 200x112 1500 5 x 440 100 x 15 1
13. he voltage approximately 10 less than that required for relay operation in Section 4 2 5 above With the voltage and current kept constant rotate the phase shifter transformer until the relay contacts open Press the relay reset Slowly rotate the phase shifter back until the relay just re operates Note the phase angle between the current and voltage Continue rotating the phase shifter in the same direction passing through the 90 condition until the relay contacts re open and it can be reset Creep back with the phase shifter until the relay once again just operates Note The new phase angle The mean of these two angles should be within 5 of 90 13 4 2 7 4 2 8 4 2 9 To check the Z1 setting Apply 50 rated volts Increase the current until the relay just operates as in Section 4 2 5 Increase the current up to the maximum of 2 x or 3 x rated as dictated by the load resistor or relay continuous rating or until the relay contacts open and can be reset If necessary reduce the voltage decreasing the impedance until the relay can be reset Note The undervoltage cut off value may be 20 Vn or 40 Vn Either increase the voltage slowly or decrease the current increasing the impedances until the relay just operates Note the voltage and the current The applied impedance x represents 2Z1 l gt 21 The colculoted Z1 should be within 15 of the reloy Z1 setting under commissioning test conditions A Fr
14. l when individual relays are to be assembled as a composite rack or panel mounted assembly Publication R6001 is a leaflet on the Modular Integrated Draw out System of protective relays Publication R6014 is a list of recommended suppliers for the pre insulated connectors Section 3 APPLICATION AND SELECTION OF SETTINGS 3 1 The satisfactory application of the MYTU 04 field failure relay requires a full knowledge of the operating parameters of the machine during normal operating conditions The maximum rotor angle at which the machine can operate within the stability limit and whether the machine has been designed for operation under line charging conditions that is leading power factors are required Once the operating conditions of the machine have been established it is possible to determine the required offset and circle diameter for the circular characteristic of the relay from a knowledge of the machine transient and synchronous reactances The general practice is to use an offset setting Z1 See Figure 1 a equal to half the machine transient reactance Xd 2 and a circle diameter Z2 See Figure 1 a equal to the synchronous reactance of the machine Xs for rotor angles up to 90 and when the machine cannot be operated at leading power factors Nevertheless when the machine has been designed to operate at leading power factors and it is provided with high speed fast acting voltage regulators that permit the operation of t
15. nsformer circuits Do not open the secondary circuit of a live CT since the high voltage produced may be lethal to personnel and could damage insulation External resistors Where external resistors are fitted to relays these may present a risk of electric shock or burns if touched Battery replacement Where internal batteries are fitted they should be replaced with the recommended type and be installed with the correct polarity to avoid possible damage to the equipment Insulation and dielectric strength testing Insulation testing may leave capacitors charged up to a hazardous voltage At the end of each part of the test the voltage should be gradually reduced to zero to discharge capacitors before the test leads are disconnected Insertion of modules and pcb cards These must not be inserted into or withdrawn from equipment whilst it is energised since this may result in damage Fibre optic communication Where fibre optic communication devices are fitted these should not be viewed directly Optical power meters should be used to determine the operation or signal level of the device gt gt gt PPP Older Products Electrical adjustments Equipments which require direct physical adjustments to their operating mechanism to change current or voltage settings should have the electrical power removed before making the change to avoid any risk of electric shock Mechanical adjustments The electrical power to the
16. om the point of pick up decrease the voltage by 10 The relay should now drop off and be capable of being reset Timing checks Put the required time delay setting on the relay Use one pole of the double pole switch to apply current and the other pole to start the time interval meter Use the appropriate time delay contact to stop the timer Apply a fault using rated current with the voltage of a value that gives a point well inside the characteristic The times obtained should be within 5 or 30ms if greater of the set time Take three timing shots to check for consistency The reset time can be measured by arranging the time interval meter to start on removing the current and to stop when the relay contact opens The time obtained should be less than 100ms Make sure the in service setting chart is completed System load checks It is unlikely that selection of Z1 to its minimum and Z2 to its maximum setting together with adjustment of excitation to produce a leading power factor would result in a relay operation It is thus recommended that the machine is run at unity power factor and a phase angle meter is used to measure the angle between A B volts and A phase current as shown in Figure 4 This should be repeated using B phase current This test can only be done if the appropriate test block is provided Care is required to ensure that current transformers are not made open circuit at any time The angle measured using A phase cur
17. rent should be about 30 lagging The angle measured using B phase current should be about 150 lagging 14 Section 5 MAINTENANCE Periodic maintenance is not necessary However periodic inspection and test is recommended This should be carried out every 12 months or more often if the relay is operated frequently or is mounted in poor environmental conditions 5 1 Repeat commissioning tests to prove correct operation or for more limited testing operate the test pushbutton Section 6 PROBLEM ANALYSIS Should any problems be experienced with the relay the commissioning tests should be repeated If the relay is found to be faulty it should be returned to ALSTOM T amp D Protection amp Control for repair and recalibration since there are no user serviceable parts inside 15 Typical load impedance LEAD Figure Normal field failure relay characteristics Anjas eunj ay pjey wosiBoip 390 g Z eun y Ajuo s l ddns amod op ADE 10 2p AYZ 404 pauinbes Z0 Z1SW Hun Alddns semod pusejx3 sailddns amod 2P AOSZ PUP ap AOZZ 404 Ajuo pau nbau s IXIy Z purwa Buc e b 2 asojaq yp iq sjouwe luou ig pauuorsip 9 q esoyaq T ayow syur Buoys gt 5 0 1 s loN 1D91 wo pemelA 909 jouw jnpow lt Z e T SJ IX Y 24 uolpjol SSDUd q q 5 yyiba 850 N V 17 440 Volts 3 Phase 4 Wire
18. riate A List the relay settings being used 5 What did you expect to happen continued overleaf 23 6 What did happen 7 When did the fault occur Instant Yes No Intermittent Yes No Time delayed Yes No Delete as appropriate By how long 8 What indications if any did the relay show 9 Was there any visual damage 10 Any other remarks which may be useful Signature Title Name in capitals Company name 24 25 26 27 ALSTOM ALSTOM T amp D Protection amp Control Ltd St leonards Works Stafford ST17 ALX England Tel 44 0 1785 223251 Fax 44 0 1785 212232 Email pcs enquiries tde alstom com Internet www alstom com 1999 ALSTOM T amp D Protection amp Control Ltd Our policy is one of continuous product development and the right is reserved to supply equipment which may vary from that described Publication R8115D Printed in England
19. tteries Technical Specifications Protective fuse rating The recommended maximum rating of the external protective fuse for this equipment is 16A Red Spot type or equivalent unless otherwise stated in the technical data section of the product documentation Insulation class IEC 61010 1 1990 A2 Class EN 61010 1 1993 A2 Class Installation IEC 61010 1 1990 A2 Category Category Ill Overvoltage EN 61010 1 1993 A2 Category Ill Environment IEC 61010 1 1990 A2 Pollution degree 2 EN 61010 1 1993 A2 Pollution degree 2 Product safety 73 23 EEC ce EN 61010 1 1993 A2 EN 60950 1992 A11 1995 1995 1995 1995 1995 1995 1995 This equipment requires a protective safety earth connection to ensure user safety Distribution level fixed installation Equipment in this category is qualification tested at 5kV peak 1 2 50us 5000 0 5 between all supply circuits and earth and also between independent circuits Compliance is demonstrated by reference to generic safety standards Compliance with the European Commission Low Voltage Directive Compliance is demonstrated 1997 by reference to generic safety standards Section 1 DESCRIPTION The MYTU 04 relay detects the loss of field supply or reduction in the field current of a synchronous generator beyond the machine stability limit It is basically a single phase mho relay with off set adjustment see Figure 1 A built
20. ttings should now be put on the relay as described in Section 3 To check Z2 setting With the rated dc or ac auxiliary supply switched on apply 50 rated volts to the relay Adjust the phase shifting transformer as necessary to make the current lead the voltage by 90 Reduce the current to zero and reset the relay Slowly increase the current until the relay first operates but do not exceed the current rating of the load resistor 2 x rated or the continuous rating of the relay 3 x rated I At the point of operation of the relay note the voltage and current The applied impedance v represents 2 Z1 Z2 Za ye Z 21 This should be within 15 of the relay Z2 setting under commissioning test conditions Check that when the current is reduced by 10 from that recorded the relay can be reset It should be noted that when the current is at a low value the applied impedance is beyond the impedance setting of the relay See Publication R6115 for some areas where a greater error may be allowed If the relay cannot be made to operate the voltage and current should be checked and the polarity of the phase angle meter and test connections affirmed Applying an impedance of say 80 of the Z Z2 setting and rotating the phase shifting transformer through a full 360 will help determine the position of the circle relative to the test circuit and phase angle measurement To check the relay characteristic angle RCA Reduce t
21. wi L F L i mM Ne Y UY T A N MAN KN N A 7 A VAN S Service Manual Type MYTU 04 Field Failure Relay ALSTOM Service Manual Type MYTU 04 Field Failure Relay 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 of ALSTOM T amp D Protection amp Control Ltd products are immune to the relevant levels of electrostatic discharge when housed in their cases 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 at the same electrostatic 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 any person without first ensuring that
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