SPi-EF SPi-OCEF - Fundamentals Ltd
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1. 0 833 x P S Where P is CT primary current rating and S is CT secondary rating The SPi OCEF is designed for use with 3 phase mounted 400 1 CT s fig 3A or alternately 2 phase mounted 400 1 CT s and a single 60 1 core balance CT as used with the SPi EF indicator fig 3B Note that when a core balance CT is used the phase mounted CT s must always be connected to terminals 1 and 3 on the SPi indicator At the rear of the indicator two switches allow the overcurrent threshold level to be set to 600A or 250A and the CT arrangement to be set 3 phase mounted CT s or 2 phase mounted and 1 core balance CT The earth fault threshold level is a nominal 50A If an existing core balance CT is used the earth fault threshold level will be dependent on the CT primary rating 3 x Phase mounted o a S o Alternative earthing arrangement Fig 3A Connections using 3 phase mounted current transformers Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 9 2 x Phase mounted CT s Alternative earthing arrangement Core Balanced CT Fig 3B Connections using 2 phase mounted CT s and one core balance CT Important note Phase mounted current transformers must be securely mounted around the cable cores at a point where the core earthed screen passes through and beyond the CT The jointing procedure for the cable termination should specify the method to be ado2. Operation 3 Fault Definition Fault Indications Fault Scenarios 3 Current Transformers 8 4 Switchgear Earthing 10 5 Specification 11 6 Installation 13 Physical Wiring Enclosure Bracket 7 Operational Checks 16 SPi EF SPi OCEF SPi OCEF Injection Test A Appendix 18 Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 2 1 GENERAL DESCRIPTION The SPi range of fault passage indicators is designed for application to distribution networks where manually operated or automated switchgear is installed When current above a threshold level is detected the indicator operates alarm contacts for remote indication and illuminates an integral high brightness Light Emitting Diode LED Indicators strategically placed in the distribution network aid identification of a faulty section of network as shown in fig 1A where a fault occurs at position A EX Tu Fault past these points Fig 1A The SPi EF and SPi OCEF indicators are compact units contained within a high strength polycarbonate case and sealed within a waterproof compound The SPi EF indicator fig 1B is used with a core balance current transformer CT mounted around a distribution cable at the switchgear end When earth current is detected in any phase conductor the SPi EF unit measures the current and if a fault is calculated an ultra bright LED is flashed For a permanent fault the indicati
3. Trasnsient Fault followed by a Permanent Fault past SPi Supply Fault Current Fault Sensing 3 mins Indication Ai 3 hours _4 Relay Fleeting or latched option If when indicating for a transient fault fault current is measured the unit will fully update for the new fault Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 7 Trasnsient Fault followed by a Transient Fault past SPi Supply Fault Current Fault Sensing Indication A 24 hours 4 3 mins 3 mins Relay Fleeting or latched option If when indicating for a transient fault fault current is measured and the line voltage is immediately restored the will indicate for a further 24 hours and fully update for any further faults Trasnsient Fault followed by a Permanent Fault BEFORE SPi Supply Source CB open Fault Current Fault Sensing Indication Relay Fleeting or latched option 3 mins Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 8 3 CURRENT TRANSFORMERS The SPi EF is designed for use with a 60 1 core balance CT having a minimum rating of 1 5VA and an accuracy of 10 up to 4 times primary current 10P4 With this CT the threshold current is 50Amps If other ratio CT s are used the operating threshold is
4. after the current dropping below the threshold set point THEN a fault is set Fault Definition indeterminate Supply YI RRS Current 500msec Curve Time 500msec maximum achieved maximum 2 2 Fault Indication A fault is indicated on the SPi by an ultra bright LED flashing at an interval of approximately 1 5 seconds For remote alarms volt free contacts are closed at the start of the indicating period The alarm contacts can be specified fleeting 2 seconds or permanently closed until the end of the indicating period The device will indicate for both transient and permanent faults The indications are as follows Transient Fault if fault current is measured and the mains supply is restored in less than 3 hours the high intensity red LED will flash repeatedly for 24 hours unless reset Permanent Fault if fault current is measured and the mains supply is still off after 3 hours the high intensity red LED will flash repeatedly for 3 hours unless reset Trigger level the fault LED will indicate when the threshold operating current is reached and until the curve time is achieved If a transient fault is being indicated and a new fault is detected all indicators will update and indicate for the new fault situation A test reset button located on the front of the SPi can be used to test the functionality of the indicator or to reset a fault indication Nortech Management Limited
5. curve time is reached see app A A full operational check of the indicator is achieved as follows Confirm power supply on Inject current below threshold level OC or EF and note LED does not flash Inject current above threshold level OC or EF and note LED does not flash Switch supply AND fault current OFF at the same time Confirm correct indications and alarms ar WD Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL 7 3 SPi OCEF Injection Tests PAGE 17 It is important that CT polarities are correct the table below shows the minimum primary injection tests that should be carried out to confirm correct secondary CT wiring connections CTA CTB CTC SPi OCEF Pin Pout Pin Pout Pin Pout Mmdication Test 1 Injection x X Er Link X X Test2 Injection X X EF Link X X Test3 Injection x x None Link X X Test4 Injection X X None Link X X Test5 Inject x x EF Test 6 Inject x x EF Test 7 Inject x X EF Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 18 Appendix A SPi EF Response against Normal Inverse amp Very Inverse curves using 0 1TM 10 00 e eae 1 00 E S n TST
6. c fe Oo 0 10 0 01 tt tt 1 10 100 PSM Standard Very SPi EF Nortech Management Limited document reference D_061_0279 issue 2 02
7. document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 5 2 3 Fault Scenarios The action of the indicator under various fault situations is shown in more detail below Transient Fault Fault Current Fault Sensing 3 min Indication 24 hr Relay Fleeting or latched option On fault detection the indicator will flash to indicate fault passage After a valid fault has been set and providing supply is restored no fault measurements are taken for 3 minutes If the line voltage is restored within 3 hours the unit will indicate for a total of 24 hours and at the same time monitor the circuit for further faults Permanent Fault supply restored before 3 hour time out period Supply Up to 3 hours Fault Current Fault Sensing Indication 24 hr Relay Fleeting or latched option If following the fault supply is not restored the unit will indicate for 3 hours If supply is restored during this period the unit will indicate for 24 hours and monitor and update for further faults Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 6 Permanent Fault supply restored after 3 hour time out period Supply More than 3 hours Fault Current Fault Sensing Indication 3 hours Relay Fleeting or latched option If following a fault supply is not restored within 3 hours the unit will reset
8. e fault 600A or 250A selectable Earth fault 50A nominal Following a fault detection the indicator will not sense a further fault for a period of 3 minutes Indicator Ultra bright LED 1 5 second flash rate 24 hours duration for transient fault 3 hours duration for permanent fault if supply is restored during this period the unit will update if a new fault is detected Remote Alarm options 1 Fleeting normally open volt free contacts 2 0 Sec standard 2 Latched normally open volt free contacts option Alarm is actively biased to the non operated position during the normal supply on period and during the fault measuring period The SPi indicators have been tested for compliance with the following standards ENVIRONMENTAL WITHSTAND Insulation Between any terminal and earth 2kV RMS for 1 minute Between independent circuits 2kV RMS for 1 minute Across normally open contacts 1kV RMS for 1 minute Transient Over voltage Between all terminals and earth or between any two terminals 5kV 1 2 50uSec High Frequency Disturbance 2 5kV Common mode longitudinal No mal operation 1kV Series mode transverse No mal operation Electrostatic Discharge 8kV contact No mal operation Fast Transient 2kV 5 50nSec 2 5kHz repetitive No mal operation steady state operated or during fault measurement Nortech Management Limited d
9. mited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 16 7 OPERATIONAL CHECKS When powered up the test reset button located on the front of the SPi can be used in two ways to confirm the operational readiness and functionality of the indicator 1 When operated the LED will flash for a short time and then steady until the test reset button is released the remote alarm relay contacts will not be operated 2 If the power supply to the SPi is removed within 15 seconds of test 1 the remote alarm contacts will close allowing confirmation of the remote fault indication circuitry The unit will indicate until supply is restored A full check for operation can be carried out by current injection across the CT secondary terminals of the indicator The test procedure is as follows 7 1 SPi EF Confirm power supply on Inject 0 7 A into SPi EF and note LED and note LED does not flash Inject 1 Amp into SPi EF and note LED flashes briefly Switch supply AND fault current OFF at the same time Confirm correct indications and alarms 0O AOON 7 2 SPi OCEF When installed and with the indicator powered up primary current injection should be carried out to confirm that the CT s are of the correct ratio and polarity When the current setting of the indicator is reached the appropriate LED will illuminate As the current is increased above the fault level threshold the LED will switch off as the fault
10. ng period is 3 hours For a transient fault the indicating period is 24 hours In each case contacts are operated for remote alarms The power supply to the indicator is taken from the local distribution network under normal system conditions When supply is detected the indicator charges over a short time and is available for fault detection and indication during and after a fault occurrence for a period of up to 6 hours for a permanent fault Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 3 Fig 1B SPi indicator SPi EF shown In practice the measurement of true fault current by use of a core balance CT requires consideration to the following Any external earth wire connections used with distribution switchgear must be routed carefully such that the cable core current can be accurately measured During the fault clearance period when the device is measuring capacitive currents can flow into the fault location from both ends of the feeder The indicator must discriminate between true fault current and short time capacitive discharge current Strong magnetic fields produced by external current flowing in earthwire connections in close proximity to the indicator or core balance CT must not cause operation of the indicator Core balance current transformers used must be unaffected by external fault currents The SPi range of indicators has been designed to operate unde
11. nortech Nortech Management Ltd Tadcaster House Keytec 7 Business Park Kempton Road PERSHORE WR10 2TA Untied Kingdom tel 44 0 8700 111 992 fax 44 0 8700 111 992 e mail info nortechonline co uk web site http www nortechonline co uk SPi EF and SPi OCEF Fault Passage Indicators TEST RESET Ppress uevtit ndicate stays 1 peame a sPi EF ERED EART NDICATOR H FAULT SELF POW USER MANUAL E amp OE Revised November 2002 Nortech Management Ltd D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 1 OVERVIEW This document describes the Operation Installation and Maintenance for two fault passage indicators SPi EF Self Powered Earth Fault indicator SPi OCEF Self Powered Over Current and Earth Fault indicator The SPi unit is connected to a local AC supply which is used to maintain operational readiness On removal of this local supply an internal power source supports the operation and any indications of the SPi When the local AC supply is restored after a period of self powered operation the SPi replenishes the standby internal power source Indication for faults is by flashing Hyper Bright LED for and additional electrical indication from auxiliary contacts THERE IS NO BATTERY IN EITHER THE SPi EF OR THE SPi OCEF Also in the range is the SPi OCEF Programmable which provides additional functionality CONTENTS Section Page 1 General Description 2 2
12. ns A L N E CT ALRM REMOVE LINK IF EARTH CONNECTED AT CT Fig 6A SPi EF connections Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 14 OVERCURRENT CT TYPE 600a 3x400A 250A V 2x400A CORE SETTING SWITCH ui 1 3 5 E 7 ALRM 3xPHASE CT LINK 7 E 2xPHASE CT 1xCORE CT LINK 5 E REFER TO MANUAL FOR CONNECTIONS REMOVE LINK IF EARTH CONNECTED AT CT Fig 6B SPi OCEF connections The connections are as follows Power Supply L N The power which is also used for supply sensing can be from 100V 250VAC Current Transformers CT 1A nominal input from core balance CT SPi EF ABCD 1A nominal inputs from either 3 phase mounted CT s or 2 phase mounted CT s and 1 core balance CT SPi OCEF Alarms Normally open isolated contacts are provided for remote signalling fault The operation of the alarm contacts is fleeting 2 seconds duration Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 15 6 3 Enclosure Detail fe poe lel SPi Base unit Base unit cable entry Fig 6C SPi case detail 6 4 Optional Mounting Bracket Detail 2 holes M6 6 holes M6 clearance clearance Side view Front view Top view Nortech Management Li
13. ocument reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 12 EMC Susceptibility 100kHz to 1gHz 3V metre on all planes no mal operation Emissions No significant emissions Current Injection Operation 50A threshold 10 up to at least 20 000A primary current for 3 Sec through 60 1 current transformer Mechanical General Case construction to IP65 Processor circuitry in lid protected in epoxy resin moulding Temperature range 25 C to 70 C ambient Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 13 6 INSTALLATION 6 1 Physical The SPi EF is constructed in a fully weatherproof polycarbonate enclosure The indicator is encapsulated into the casing lid with a reset test button in a central position under the information nameplate Connections are made from the indicator to a terminal strip mounted to the rear of the casing Fig 6A shows the connections for the SPi EF and fig 6B for the SPi OCEF indicator Three 20mm cable gland entry holes are provided one with blanking plug for mains supply CT s and alarm output fig 6C The indicator should be mounted for good visibility and as close as practical to the CT One core of the CT should be connected to earth for safety Any external earth wires should be routed to maintain a minimum clearance of 100mm from the SPi EF 6 2 Wiring Connectio
14. pted in order to ensure electrical stress control The secondary wiring must be earthed as shown by figure 3A and 3B Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL 4 SWITCHGEAR EARTHING PAGE 10 Earth fault current is returned to source through the path of least resistance When the fault occurs in a cable system the majority of return current will flow through the cable sheath thus resulting in a null output from a core balance CT as shown in figure 4A MINIMAL OUTPUT Fig 4A Fault Current Return Fault Current This effect can be prevented if the cable earthing connection between the cable and adjacent switch is routed through the core balance CT figure 4B Fault Current Return Fault Current Correct output Fig 4B Fault Current Return Fault Current Correct output Where single core cables are used each sheath earth wire must be routed through the single core balance CT Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL 5 SPECIFICATION PAGE 11 Case Polycarbonate 122mm H x 120mm W x 105mm D Power Supply options 1 110 250V 2 40 65V Charge Rearm time From loss of supply 10 seconds for first 30 minutes and then 60 seconds Threshold fault current SPi EF Earth fault only as formula section 3 above SPi OCEF Phas
15. r these most onerous conditions and give reliable indications The SPi OCEF indicator is used with either 3 phase mounted CT s or alternatively 2 phase mounted and one core balance CT The indicator monitors for phase to phase and earth faults and operates to give remote alarms and local indications as for the SPi EF indicator Nortech Management Limited document reference D_061_0279 issue 2 02 SPi EF and SPi OCEF USER MANUAL PAGE 4 2 OPERATION The SPi is powered from the local mains supply under system normal conditions When first energised the indicator is ready for fault indication after 60 seconds If supply is lost and then restored within 30 minutes the indicator is ready for fault indication after 10 seconds Measurement of earth current is made every 1mSec When current above the threshold setting of the indicator is measured a fault calculation is initiated The algorithm used for fault measurement allows the indicator to grade with the minimum settings likely to be used by the source protection relays and at the same time avoid possible mis measurement due to capacitive charge currents The indicator characteristic is shown in App A against typical source protection minimum settings 2 1 Fault Definition The indicator determines a fault as follows IF supply was on 500mS before the current exceeds the threshold set point AND the current exceeds the characteristic criteria app A AND the supply is off within 500mS
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