Document Number: ECP 11-0506 Version: 3.0 Date: 01/05/2013 THIS IS AN UNCONTROLLED DOCUMENT, THE READER MUST CONFIRM ITS VALIDITY BEFORE USE ENGINEERING COMMISSIONING PROCEDURE ECP 11-0506 DISTRIBUTION TRANSFORMER COMMISSIONING PROCEDURE Network(s):EPN, LPN, SPN Summary:This procedure details the testing and commissioning procedures for distribution transformers. Originator:Stephen TuckerDate:01/05/2013 Approved By:Steve MockfordApproved Date:03/07/2013 Review Date:31/03/2018 This document forms part of the Companys 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 originator of the current issue. Document History (The document history notes below are intended as a guide only and may not cover all of the changes. If you wish to make use of this document it should be read in full.) VersionDateDetailsOriginator 3.002/05/2013Reviewed for G81 websiteStephen Tucker 2.004/11/2011Document reviewed. Dual voltage transformer and energisation checks added Stephen Tucker/ Sinad Hogan 1.213/09/2011Reclassification of document from Installation and Commissioning Manual 5.06 John Lowe 1.118/03/2011RebrandedJerry Wells 1.024/09/2009OriginalStephen Tucker Distribution Transformer Commissioning ProcedureDocument Number: ECP 11-0506 Version: 3.0 Date: 01/05/2013 UK Power Networks 2013 All rights reserved 2 of 6Contents 1Introduction ............................................................................................................. 3 2Scope ....................................................................................................................... 3 3References ............................................................................................................... 3 4Abbreviations and Definitions ................................................................................ 4 5Equipment ................................................................................................................ 4 6Inspection ................................................................................................................ 4 7Tap Changer Checks ............................................................................................... 5 8Winding Insulation Resistance ............................................................................... 5 9Winding Selector Check (Dual Voltage Transformer Only) .................................. 6 10Energisation ............................................................................................................. 6 11Asset Data ................................................................................................................ 6 12Test Equipment ....................................................................................................... 6 13Certification ............................................................................................................. 6 Distribution Transformer Commissioning ProcedureDocument Number: ECP 11-0506 Version: 3.0 Date: 01/05/2013 UK Power Networks 2013 All rights reserved 3 of 61Introduction 1.1Thisproceduredetailsthetestingandcommissioningproceduresfordistribution transformers that shall be satisfied before the transformer can be accepted as fit for service and energisation.1.2ThisprocedureshallbecarriedoutbytheCommissioningEngineerorhis appointedrepresentative,whoshallbeanAuthorisedPersonhavingappropriate training and experience. 1.3This procedure shall be carried out in accordance with the requirements of theUK Power Networks Distribution Safety Rules. 1.4Thisprocedureshallbecarriedouthavingregardtotherequirementsand recommendationsofthemanufacturer.Ifconflictexistsbetweentherequirements of the manufacturer and those ofUK Power Networks the matter shall be referred to Asset Management (or your UK Power Networks nominated contact). 1.5Thisprocedureassumesthattheunithasbeeninstalledinaccordancewiththe appropriate procedures and that the equipment is isolated from the network. 1.6The results of all observations, tests, adjustments and all relevant remarks shall be recorded on the associated test form. 2Scope 2.1Thisprocedureappliesto11kVand6.6kVground-mountedandpole-mounted distribution transformers. 2.2ThisprocedureisintendedforusebyUKPowerNetworksfieldstaff,contractors and external connection providers. 3References 3.1This procedure should be read in conjunction with the following references: UK Power Networks Distribution Safety Rules. Manufacturer'sinstallationandoperationinstructions,e.g.CGPowerSystems (previously known as Pauwels), Efacec, Schneider etc (all available from CDL > Reference Library > Manufacturers). 3.2This procedure should be used with the following test forms: ECP 11-0506a Distribution Transformer Test Form. ECP 11-0504 Substation Energisation Procedure. Distribution Transformer Commissioning ProcedureDocument Number: ECP 11-0506 Version: 3.0 Date: 01/05/2013 UK Power Networks 2013 All rights reserved 4 of 64Abbreviations and Definitions 4.1The following abbreviations are used throughout this procedure. TermDefinition ARTUK Power Networks Asset Registration Team CDLUK Power Networks Central Document Library 5Equipment 5.1Thefollowingtestequipmentisrequiredtocarryoutthetestsdetailedinthis procedure: 1kV insulation resistance tester (e.g. Megger). 6Inspection 6.1Record the substation and transformer details on the test form. 6.2Carryoutavisualinspectionofthetransformerasdetailedbelowreferringtothe manufacturers manual where appropriate. If possible the Commissioning Engineer shallrectifyanynon-conformances.However,allequipmentdefectsshallbe referred to Asset Management (or your UK Power Networks nominated contact).Checkthatthetransformeriscorrectlyinstalledandthestabilityfootfully supported where applicable. Check that the transformer is undamaged. Checkthatallexternalsurfacefinishesareundamagedandanydamaged paintwork has been repaired. Checkthattheearthingterminal(s)aresecurelyconnecteddirectlytothe substationearthelectrodesandthatpainthasbeenremovedfromtheearth contact points. Check that there are no oil leaks. Check that the transformer oil level is satisfactory (if sight glass is available). Check that any valves are securely closed. Check that the desiccant dehydrating breather is correctly fitted (if applicable). Check that the free breather is clear and the end cap has been removed on free breathing transformers. Check that the pressure relief device is not blocked and remove any packing if labelled adjacent to device on sealed transformers. Check that the HV bushings are satisfactory. Check that the LV mono block/bushings are satisfactory. Check the transformer ID labels are fitted (if applicable). Check oil temperature gauge is fitted in position (if applicable). Fordual-ratiotransformerscheckthatthecorrectvoltageratiohasbeen selected and the position locked. Distribution Transformer Commissioning ProcedureDocument Number: ECP 11-0506 Version: 3.0 Date: 01/05/2013 UK Power Networks 2013 All rights reserved 5 of 67Tap Changer Checks 7.1Carry out the followingtap changer checks referring to themanufacturers manual where appropriate: Operate the tap changer through all positions while off-circuit. Set the desired tap position. Lock the tap changer. 7.2Record the tap position on the test form. 8Winding Insulation Resistance 8.1Measure HV winding insulation resistance as follows: ConnecttheLVwindingstogetherandtoearthviatheneutral-earthlinkand substation earth. Connect a 1kV insulation resistance tester between the transformer HV winding and earth. The insulation resistance should be greater than 100M . The transformer should be discharged after the measurement.Note:Fortransformer-mountedunitstestfromterminalsL1orL2orL3onring switch 1 with ring switch 1 closed, ring switch 2 open and the circuit-breaker closed. 8.2Measure LV winding insulation resistance as follows: Ifthetransformerhasatransformer-mountedLVfuse-cabinetitwillbe necessary to temporarily remove the neutral-earth link.Connect the HV windings together and to earth via the substation earth. Connect a 1kV insulation resistance tester between the transformer LV winding and earth. The insulation resistance should be greater than 100M . The transformer should be discharged after the measurement. Replace the neutral-earth link if it has been removed previously. Note:Fortransformer-mountedunitsearththeHVwindingviathecircuit-breaker earthing switch and test with ring switch 1 open, ring switch 2 open and the circuit-breaker open. Distribution Transformer Commissioning ProcedureDocument Number: ECP 11-0506 Version: 3.0 Date: 01/05/2013 UK Power Networks 2013 All rights reserved 6 of 69Winding Selector Check (Dual Voltage Transformer Only) 9.1Check that the voltage selection handle is secure. 9.2Operate the winding selection switch several times.9.3Measure the HV resistance at both voltage positions. The resistance per phase at 11kV should be at least twice the resistance per phase at 6.6kV. 9.4Select the correct winding. 9.5If there is any doubt that the internal winding selection mechanism is not operating correctlythetransformershallnotbeenergisedandthedefectreportedtoAsset Management (or your UK Power Networks nominated contact). 10Energisation 10.1Energisationincludingphasingchecksshallbecarriedoutinaccordancewith ECP 11-0504. 11Asset Data 11.1CompletetheassetdataformandeithersendittotheAssetRegistrationTeam (ART),emailittotheappropriatemailbox(ART.EPN@ukpowernetworks.co.uk, ART.LPN@ukpowernetworks.co.uk, ART.SPN@ukpowernetworks.co.uk) or send it to your UK Power Networks nominated contact. 12Test Equipment 12.1Recordthepurpose,make,typeandserialnumberofalltestequipmentused during commissioning on the test form. 13Certification 13.1When the commissioning has been satisfactorily completed, sign and date the test form.Placeacopyofthetestformon-siteinaplasticwalletandinasecure location.