Document Number: ECP 11-0511 Network(s): Summary: ENGINEERING COMMISSIONING PROCEDURE ECP 11-0511 GROUND-MOUNTED SWITCHGEAR COMMISSIONING PROCEDURE EPN, LPN, SPN This procedure details the testing and commissioning procedures for groundmounted switchgear including ring main units and circuit breakers with time-limit fuses and switches. Author: John Mason Approver: Paul Williams Date: 10/09/2018 This document forms part of the Company s Integrated Business System and its requirements are mandatory throughout UK Power Networks. Departure from these requirements may only be taken with the written approval of the Director of Asset Management. If you have any queries about this document please contact the author or owner of the current issue. Applicable To UK Power Networks External Asset Management G81 Website Capital Programme UK Power Networks Services Connections Contractors Health & Safety ICPs/IDNOs Legal Meter Operators Network Operations Procurement Strategy & Regulation Technical Training THIS IS AN UNCONTROLLED DOCUMENT, THE READER MUST CONFIRM ITS VALIDITY BEFORE USE
Revision Record Version 8.0 Review Date 04/12/2020 Date 18/07/2018 Author John Mason Reason for update: Updated to clarify the CT Loop Continuity test. What has changed: ECP 11-0511i updated to instruct that the test link must remain in place during testing. ECP 11-0511i updated to illustrate customer trip connections. ECP 11-0511i Schematic diagram removed (can be found in Alfresco). ECP 11-0511c updated to instruct that the test link must remain in place during testing. ECP 11-0511c Schematic diagram removed (can be found in Alfresco). Version 7.0 Review Date 04/12/2020 Date 27/02/2018 Author John Mason Reason for update: Test form updates. What has changed: ECP 11-0511a updated to illustrate customer trip connections. ECP 11-0511e updated to illustrate customer trip connections. Version 6.0 Review Date 04/12/2020 Date 24/05/2017 Author Ian Marshall Reason for update: Updated following concerns raised by UK Power Networks field engineers around the overcurrent and earth fault release test values obtained. What has changed: Lucy VRN2a and VRE2a test form updated (ECP 11-0511e). Lucy CN2a and VCE2a test form updated (ECP 11-0511g). New test form ECP 11-0511i created. Expected vales clarified in Sections 15.1 and 16.1. Version 5.0 Review Date 04/12/2020 Date 09/09/2016 Author Ian Marshall Reason for update: Updated following introduction of new switchgear from Lucy. What has changed: Lucy VRN2a and VRE2a test form updated (ECP 11-0511e). Lucy CN2a and VCE2a test form updated (ECP 11-0511g). Version 4.0 Review Date 04/12/2020 Date 25/11/2015 Author Stephen Tucker Reason for update: Procedure and test forms updated to incorporate minor revisions following feedback from commissioning training course. What has changed: Test access continuity checks added (Section 10). HV insulation testing document reference updated (Section 9, 11and test forms). RN2/RN2c secondary injection values corrected on form ECP 11-0511a and ECP 11-0511c. FPI test connections updated on form ECP 11-0511e and ECP 11-0511f. Requirement to send copy of the test form to the ART added (Section 21). UK Power Networks 2018 All rights reserved 2 of 16
Version 3.0 Review Date 31/05/2018 Date 09/07/2013 Author Stephen Tucker General revision following field staff feedback. Shunt trip tests added. Secondary injection values in test forms a and c amended. Efacec test form h added. Reviewed for G81 website. Version 2.0 Review Date Date 26/03/2009 Author Stephen Tucker General revision and test forms for Lucy SSEa, VCN2a and VCE2a added. Version 1.0 Review Date Date 24/11/2006 Author Stephen Tucker Original. UK Power Networks 2018 All rights reserved 3 of 16
Contents 1 Introduction... 5 2 Scope... 6 3 References... 7 4 Abbreviations and Definitions... 7 5 Equipment... 8 6 Switchgear Designations... 8 7 Inspection... 8 8 Functional Checks... 9 9 Transformer Winding Insulation Resistance (Transformer-mounted Units Only)... 9 10 Switchgear Continuity Test... 10 11 High Voltage Insulation Test... 10 12 FPI CT Wiring Tests... 11 13 Protection CT Wiring Tests... 12 14 Time-Limit Fuses (TLF)... 12 15 Primary Injection Test (Free-standing Units Only)... 13 16 Secondary Injection Test (Transformer-mounted Units Only)... 14 17 Shunt Trip Coil and Emergency Trip (if fitted)... 15 18 Final Checks... 15 19 Test Equipment... 15 20 Certification... 15 21 Asset Data and Information... 15 21.1 UK Power Networks... 15 21.2 Independent Connection Provider (ICP)... 16 UK Power Networks 2018 All rights reserved 4 of 16
1 Introduction 1.1 This procedure details the testing and commissioning procedures for groundmounted switchgear, including ring main units and circuit breakers with time-limit fuses and switches, that shall be satisfied before the unit can be accepted as fit for service and energisation. 1.2 This procedure shall be carried out by the Commissioning Engineer or his appointed representative, who shall be an Authorised Person having appropriate training and/or experience. 1.3 This procedure shall be carried out in accordance with the requirements of the UK Power Networks Distribution Safety Rules. 1.4 This procedure shall be carried out having regard to the requirements and recommendations of the manufacturer. If conflict exists between the requirements of the manufacturer and those of UK Power Networks the matter shall be referred to Asset Management (or your UK Power Networks nominated contact). 1.5 This procedure assumes the following: When the switchgear is attached to a distribution transformer, it is not possible to carry out primary injection tests of the protection CTs. In all other applications full testing shall be carried out. The ring switch cable boxes are not connected. The substation earth conductor is connected to the low voltage/high voltage switchgear earth bar. 1.6 The results of all observations, tests, adjustments and all relevant remarks shall be recorded on the appropriate test form. 1.7 Where possible testing shall be carried without disconnecting or disturbing any wiring. UK Power Networks 2018 All rights reserved 5 of 16
2 Scope 2.1 This generic procedure applies to 11kV and 6.6kV ring main units and other switchgear with time-limit fuse (TLF) or time fuse-link (TFL) 1 protection which are either transformer-mounted or free-standing as detailed below. Merlin Gerin and Schneider RN2, RN2c and RE2c ring main units. Merlin Gerin and Schneider CN2 and CE2 circuit-breakers. Merlin Gerin and Schneider SE6 switch. Lucy SCRMU, VRN, VRN2, VRE, VRN2a and VRE2a ring main units. Lucy SSEa switch. Lucy VCN2a and VCE2a circuit-breakers. Efacec Fluofix GCT ring main unit. 2.2 The associated test forms, which should be read in conjunction with this procedure, include specific schematic diagrams, connections and trip levels for the items of switchgear listed above. 2.3 This procedure is written with reference to a ring main unit but it can also be applied to individual switches and circuit-breakers. 2.4 Switchgear with protection relays is covered in procedure ECP 11-0512. 2.5 Air circuit-breakers are covered in procedure ECP 11-0514. 2.6 The parasitic load trip unit (PLTU) is covered in procedure ECP 11-0529. 2.7 Distribution transformer is covered in procedure ECP 11-0506. 2.8 This procedure is intended for use by UK Power Networks field staff, contractors and external connection providers. 1 The term TLF is used throughout this procedure to refer to both TLF and TFL protection. UK Power Networks 2018 All rights reserved 6 of 16
3 References 3.1 This procedure should be read in conjunction with the following references: UK Power Networks Distribution Safety Rules. EDS 05-4001 Fuse Ratings at Distribution Substations (Internal document). ECS 11-0006 HV Insulation Testing. ECP 11-0506 Distribution Transformer Commissioning Procedure. ECP 11-0512 Ground Mounted Switchgear with Relays Commissioning Procedure. ECP 11-0514 ACB Commissioning Procedure. ECP 11-0529 PLTU Commissioning Procedure. Schneider Electric Ringmaster Range Installation, Operation and Maintenance Instructions, V5 December 1999 (RN2/RN6). Schneider Electric Ringmaster Range Installation, Operation and Maintenance Instructions, V10 July 2005 (RN2c/RN6c/RE2c). Lucy SCRMU Installation, Operation and Maintenance Manual. Lucy VRN Installation, Operation and Maintenance Manual. Lucy Sabre VRN2 Installation, Operation and Maintenance Manual. Lucy Sabre VRN2a Installation, Operation and Maintenance Manual. Efacec Fluofix GCT Installation, Operation and Maintenance Manual. 3.2 This procedure should be used with the following test forms: ECP 11-0511a Schneider RN2, RN2c & RE2c. ECP 11-0511b Schneider SE6. ECP 11-0511c Schneider CN2 & CE2. ECP 11-0511d Lucy SCRMU, VRN & VRN2. ECP 11-0511e Lucy VRN2a & VRE2a. ECP 11-0511f Lucy SSEa. ECP 11-0511g Lucy VCN2a & VCE2a. ECP 11-0511h Efacec Fluofix GCT. 4 Abbreviations and Definitions 4.1 The following abbreviations are used throughout this procedure. Term ART CT FPI RTU TFL TLF VT Definition UK Power Networks Asset Registration Team Current Transformer Fault Passage Indicator Remote Terminal Unit Time Fuse-link (same as TLF) Time-limit Fuse (same as TFL) Voltage Transformer UK Power Networks 2018 All rights reserved 7 of 16
5 Equipment 5.1 The following equipment is required to carry out the tests detailed in this procedure: 1kV insulation resistance tester (e.g. Megger). 5kV insulation resistance tester (e.g. Megger). Multimeter (or other continuity checker). Note: Fused leads should not be used for measuring resistance as false readings can be obtained. Ductor tester. Injection test set (suitable for primary/secondary injection). TLF shorting-links. 100A shorting-link or cable. RTU simulator (if required). 6 Switchgear Designations 6.1 The diagram below shows the switch/circuit-breaker and terminal designations referred to throughout this document. Circuit-breaker/ Tee-off (CB) L1 L2 L3 Ring Switch 1 (RSW1) L1 L2 L3 Ring Main Unit L1 L2 L3 Ring Switch 2 (RSW2) 7 Inspection 7.1 Record the substation, switchboard number, if applicable, transformer and current transformer (CT) details on the test form. 7.2 Carry out a visual inspection of the switchgear as detailed below. If possible the Commissioning Engineer shall rectify any non-conformances. However, all equipment defects shall be referred to UKPN Asset Management. Check that the switchgear is undamaged and is correctly mounted and secured to the plinth and to the transformer flange (if applicable). Check that the earth terminal(s) of the switchgear are securely connected directly to the substation earth electrodes. Check that all external surface finishes are undamaged. UK Power Networks 2018 All rights reserved 8 of 16
8 Functional Checks 8.1 Carry out the checks detailed below and record the results on the test form. In the event of non-conformance with the functional expectation the result shall be recorded on the test form and the equipment shall not be accepted into service. Check the opening and closing of door including the supporting struts if fitted. Check that the pointer of the SF 6 gas pressure indicator is in the healthy sector tap the site glass to overcome any stiction. 8.2 Check for correct operation of the circuit-breaker, ring switches, earth switches, test access covers and associated interlocks/switch position indicators are in accordance with the manufacturer's instructions. Open and close switches. Earth switches cannot be operated when service selected. Switch/circuit-breaker cannot be operated when earth selected. Open and close earth switches. Test access cannot be opened when switch/circuit-breaker in On and Off position. Test access can be opened when earth switch closed. Switch/circuit-breaker cannot be operated when test access open. 8.3 Carry out a functional check of each motorised actuator using an RTU simulator (LPN Remsdaq RTU only). 9 Transformer Winding Insulation Resistance (Transformer-mounted Units Only) 9.1 Carry out the transformer wining insulation test as detailed below using the test voltages from ECS 11-0006 and record the results on the test form. 9.2 Measure HV winding insulation resistance as follows: Connect the LV windings to earth via the neutral link and substation earth. Connect an insulation resistance tester between the transformer HV winding and earth. The test may be carried out from terminals L1 or L2 or L3 on either ring switch with ring switch closed and the circuit-breaker closed. The insulation resistance should be greater than 100M. 9.3 Measure LV winding insulation resistance as follows: If the transformer has a transformer-mounted LV fuse-cabinet it will be necessary to remove the neutral-earth link. Connect the HV windings to the substation earth via the circuit-breaker earthing switch. Connect an insulation resistance tester between the transformer LV winding and earth. The test may be carried out from terminals L1 or L2 or L3. The insulation resistance should be greater than 100M. Replace the neutral-earth link if removed above. 9.4 The tests for free-standing transformers are covered by the transformer commissioning procedure (ECP 11-0506). UK Power Networks 2018 All rights reserved 9 of 16
10 Switchgear Continuity Test 10.1 Carry out a switchgear continuity test using a multi-meter or a Ductor tester (for extensible switchgear with site assembled busbars) as detailed below and record the results on the test form. Note: Ensure the cable box connection studs are tight otherwise high resistance readings may be encountered. 10.2 On transformer-mounted units: Close both ring switches and open the circuit-breaker. Measure the continuity between each phase on ring switch 1 to each on phase ring switch 2. Close ring switch 1, open ring switch 2 and close the circuit-breaker. Measure the continuity between L1 to L2 and L2 to L3 on ring switch 1. 10.3 On free-standing units: Close both ring switches and close the circuit-breaker. Measure the continuity between each phase on ring switch 1 to each phase on ring switch 2 and each phase on the circuit-breaker. 10.4 Close ring switch 1 to earth and open ring switch 2. Measure the continuity from phase L1, L2 and L3 on ring switch 1 to earth. 10.5 Close ring switch 2 to earth and open ring switch 1. Measure the continuity from phase L1, L2 and L3 on ring switch 2 to earth. 11 High Voltage Insulation Test 11.1 Carry out high voltage insulation test as detailed below using the test voltages from ECS 11-0006 and record the results on the test form. 11.2 Close both ring switches and open the circuit-breaker for transformer-mounted units (close the circuit-breaker for free-standing units). Measure the insulation between each phase and earth with the other two phases earthed. 11.3 Open ring switch 1, close ring switch 2 and open the circuit-breaker for transformermounted units (close the circuit-breaker for free-standing units). Measure the insulation between L1, L2, L3 on ring switch 1 and earth with L1, L2, L3 on ring switch 2 earthed (L1, L2, L3 on the circuit-breaker should also be earthed for free-standing units). 11.4 Close ring switch 1, open ring switch 2 and open the circuit-breaker. Measure the insulation between L1, L2, L3 on ring switch 1 and earth with L1, L2, L3 on ring switch 2 earthed (L1, L2, L3 on the circuit-breaker should also be earthed for free-standing units). UK Power Networks 2018 All rights reserved 10 of 16
12 FPI CT Wiring Tests 12.1 Carry out the FPI wiring tests as detailed below and record the results on the test form. 12.2 Disconnect the RTU/FPI if fitted. Note: This will ensure the RTU/FPI is not damaged during insulation testing and will ensure that the RTU/FPI wiring is eliminated when measuring CT loop continuity. 12.3 Measure the CT insulation resistance as follows: If applicable 2 remove the CT shorting-link. Temporarily disconnect the CT wiring, earth link or CT star point as detailed on the relevant test form. Measure the insulation resistance to earth of the CTs using a 1kV insulation resistance tester. The insulation resistance should be greater than 100M. Reconnect any wiring or links removed above on completion of the test. 12.4 Measure the CT loop continuity as follows: If applicable 2 remove the CT shorting-link. At the CT wiring terminal block identify the terminals for L1 CT and measure the resistance of the CT. The resistance should be in the region of 1-2. Repeat for L2 and L3 CT circuits. 12.5 Repeat for all switches with FPI CTs. 12.6 Reconnect FPI/RTU if applicable. 2 Some modern switchgear (e.g. Lucy VRN2a) uses an electronic shorting-block in place of a physical link that automatically shorts the CTs when the output wiring is disconnected. UK Power Networks 2018 All rights reserved 11 of 16
13 Protection CT Wiring Tests 13.1 Carry out the protection CT wiring tests as detailed below and record the results on the test form. 13.2 Measure the CT circuit insulation resistance as follows: Temporarily remove the CT wiring earth link. Measure the insulation resistance to earth of the CTs using a 1kV insulation resistance tester. The insulation resistance should be greater than 100M. Replace the earth link on completion of the test. 13.3 Measure the CT loop continuity using the method below. Remove each TLF, if fitted. Temporarily remove the CT ratio shorting-link. Measure the continuity of the L1 CT, trip coil and wiring from the CT ratio terminals. The resistance should be in the region of 1-2.5 depending on the components in the circuit being measured. Replace the CT ratio shorting-link. Repeat for L2 and L3 CT circuits. Figure 13-1 Schneider RN2c CT Ratio Selection Figure 13-2 Lucy VRN2a CT Ratio Selection 14 Time-Limit Fuses (TLF) 14.1 Select the appropriate CT ratio and TLF rating in accordance with EDS 05-4001. 14.2 Select the required CT ratio by moving the link to the required ratio (see Figure 13-1 and Figure 13-2) referring to the manufacturer's manual for more detailed instructions. Note: switchgear is generally supplied with the 100/5 ratio selected. 14.3 If fitted, set the CT ratio label to match the selected ratio and record the CT ratio on the test form. 14.4 Select two TLFs with the correct rating and check them for continuity. The TLFs should be fitted on completion of the testing. Note: TLFs are normally only fitted in the overcurrent circuits and not the earth fault circuit. 14.5 Record the TLF rating on the test form. UK Power Networks 2018 All rights reserved 12 of 16
15 Primary Injection Test (Free-standing Units Only) 15.1 For free-standing units carry out an earth fault and overcurrent release test on each phase of the circuit-breaker as described below and record the results on the test form. Note: The circuit-breaker trip coils are designed to operate in response to the instantaneous application of a current within the specified range. Therefore they may not operate successfully when the current is gradually applied, as in the first part of these tests. This shall not be regarded as a non-conformance, and the procedure shall be completed by instantaneous application of the trip current. Expected test values for CT ratio 50/5 or 100/5 should be <35A 15.2 Carry out the earth fault release test as follows: Remove the TLFs if fitted. Connect a shorting-link across the terminals of each pair of TLF connection studs. Close ring switch 1, open ring switch 2 and close the circuit-breaker. Connect the injection test set between L1 on ring switch 1 and L1 on the circuitbreaker. Slowly increase the primary injection current from zero until the circuit-breaker trips. If the circuit-breaker trips at any value of current within the specified range, record the value of the injection current. If the circuit-breaker does not trip within the specified range, repeat the test with the current preset to the maximum permissible value and apply instantaneously by switching the injection test set OFF and then ON. Repeat the test for L2 and L3. Remove shorting-link from TLF connection studs. 15.3 Carry out the overcurrent release test as follows: Close ring switch 1, open ring switch 2 and close the circuit-breaker. Connect a shorting-link across the L1, L2, L3 on the circuit-breaker. Connect the injection test set between L1 and L2 on ring switch 1. Slowly increase the primary injection current from zero until the circuit-breaker trips. If the circuit-breaker trips at any value of current within the specified range, record the value of the injection current. If the circuit-breaker does not trip within the specified range, repeat the test with the current preset to the maximum permissible value and apply instantaneously by switching the injection test set OFF and then ON. Repeat the test with the test set connected between L2 and L3 on the circuit-breaker. Remove the shorting-link from the circuit-breaker. Replace the TLFs. UK Power Networks 2018 All rights reserved 13 of 16
16 Secondary Injection Test (Transformer-mounted Units Only) 16.1 For transformer-mounted units carry out an earth fault and overcurrent release test on each phase of the circuit-breaker as described below and record the results on the test form. Note: The circuit-breaker trip coils are designed to operate in response to the instantaneous application of a current within the specified range. Therefore they may not operate successfully when the current is gradually applied, as in the first part of these tests. This shall not be regarded as a non-conformance, and the procedure shall be completed by instantaneous application of the trip current. Expected test values for the following CT ratio s: 50/5 = <3.5A, 100/5 = <7.0A 16.2 Carry out the earth fault release test as follows: Remove the TLFs if fitted. Connect a shorting-link across the terminals of each pair of OC TLF connection studs (L1 and L3). Close the circuit-breaker. Connect the injection test set across the earth fault trip coil i.e. between L2 phase CT and the CT earth link. Slowly increase the secondary injection current from zero to the maximum permissible value. If the circuit-breaker trips at any value of current within the specified range, record the value of the injection current. If the circuit-breaker does not trip within the specified range, repeat the test with the current preset to the maximum permissible value and apply instantaneously by switching the injection test set OFF and then ON. Remove shorting-link from TLF connection studs. 16.3 Carry out the overcurrent release test as follows: Close the circuit-breaker. Connect the injection test set across the L1 phase overcurrent trip coil i.e. between the L1 phase CT and the L2 phase CT. Slowly increase the secondary injection current from zero to the maximum permissible value. If the circuit-breaker trips at any value of current within the specified range, note the value of the injection current. If the circuit-breaker does not trip within the specified range, repeat the test with the current preset to the maximum permissible value and apply instantaneously by switching the injection test set OFF and then ON. Repeat the test with the injection test set connected across the L3 phase overcurrent trip coil i.e. between the L2 phase CT and the L3 phase CT. Replace the TLFs. UK Power Networks 2018 All rights reserved 14 of 16
17 Shunt Trip Coil and Emergency Trip (if fitted) 17.1 Check that the correct voltage has been selected on the shunt trip coil. 17.2 Locate the shunt trip coil terminals. 17.3 Using an appropriate test set apply either 70% (dc) or 85% (ac) of the rated voltage to the shunt trip coil and the circuit-breaker should trip. 17.4 Close the circuit-breaker. 17.5 Using an appropriate test set apply 100% of the rated voltage to the shunt trip coil and the circuit-breaker should trip. 17.6 Check that the emergency trip button correctly trips the circuit-breaker. 18 Final Checks 18.1 On completion of the commissioning tests check the following: Correct CT ratio selected. Correct TLF rating selected and fitted. All links are replaced and secure. Check FPI CT shorting-link(s) 3 are replaced if CTs are not used or not connected to FPI or RTU. Reconnect umbilical cable to RTU (if fitted). 19 Test Equipment 19.1 Record the make, type, serial or asset number and calibration date of all test equipment used during commissioning on the test form. 20 Certification 20.1 When all the tests have been satisfactorily completed, sign and date the test form. The test form should be left on-site in a plastic wallet and in a secure location. 21 Asset Data and Information 21.1 UK Power Networks 21.1.1 Send a copy of the completed test form and the asset data form to the Asset Registration Team (ART) via the appropriate mailbox below. ART.EPN@ukpowernetworks.co.uk. ART.LPN@ukpowernetworks.co.uk. ART.SPN@ukpowernetworks.co.uk. 3 Some modern switchgear (e.g. Lucy VRN2a) uses an electronic shorting-block in place of a physical link that automatically shorts the CTs when the output wiring is disconnected. UK Power Networks 2018 All rights reserved 15 of 16
21.2 Independent Connection Provider (ICP) 21.2.1 Send a copy of the completed test form and the asset data form to the Competitionin-Connections Delivery Project Manager. UK Power Networks 2018 All rights reserved 16 of 16