印度某MW电厂电气作业指导书54

autotransformer第26页共26页InstructionforinstallationandtestTheautotransformer1.Relateddocumentationsandstandards1.1.TheChinesestandard(GBJ148-90):Codeforconstructionandacceptanceofthepowertransformer1.2.TheChinesestandard(GB50150-91):Standardforhand-overtestofelectricequipment1.3.TheChinesestandard(DL/T527-95):Operationcodeforpowertransformer1.4.TheChinesestandard(DL408-91):Operationcodeforpowerplantsafety1.5.TheChinesestandard(DL560-95):Operationcodeforelectricsafetyinhighvoltagelaboratory1.6.TheChinesestandard(DL/T5043-95):Designstandardforelectricallaboratoryofthermalpowerplant1.7.TheChinesestandard(SD187-86):Guideprincipleofanalysisandjudgeforsolublegasesintransformeroil1.8.TheChinesestandard(DL/T5161.3-2002):Specificationforconstructionqualitycheckoutandevaluationofelectricequipmentinstallation2.Receiptandstorage2.1.Examinethestateofthedevicesandthematerialsreceivedtocheckthatitcorrespondswithwhatwasordered.2.2.Checkallpackagesforexternalsignsofdamage.2.3.Pleasecheckconditionandqualityofthedevicesandthematerials,andcomparethemwiththepackinglist.2.4.Ifonunpacking,whichmustbecarriedoutcarefully,anydamageorirregularityisnoted,notifythiswithindefiniteperiodofreceiptofthegoods,notificationmustindicatetheshippingnotenumber.2.5.Ifthedevicesistobestoredforevenshortperiodsbeforebeingputintoservice,afterreceiptitisadvisabletoputitbackintoitsrelativecontainerandcoveritwithawaterprooftarpaulin.Useadryanddust-freeambientforstoragewithoutanyaggressivechemicalagents.Placethedeviceandanyfixedpartonahorizontalsurfacenotindirectcontactwiththefloor,butonasuitablesupport.2.6.Selectalocationforthedeviceinaclean,dry,vibration-freeareawithmoderatetemperature.2.7.Withregardtolifting,followtheseinstructions:thedevicesmustbeplacedonasturdysurfaceandpreferablyliftedusinganappropriateliftingforktruck.Theuseofropesis,however,permitted:inthiscasetheliftingropesmustbehookedfirmly.3.Installation3.1.Positionthetransformerinordertothegasrelaypipewith1%~1.5%upslopealongoilstreamdirection.Fixthewheelsofthetransformersolidly.Qualitystandardsinstallingtheoil-immersedtransformersareasshownintable3.1.Table3.1.:Installationoftheoil-immersedtransformersItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationInstallationofthefoundationBuilt-infittingsAccordancewiththedesignsCheckdependonthedrawingsHorizontalerrorsofthefoundation<5mmCheckbyaUshapepipeoralevelgageErrorofdistancebetweentherails<5mmCheckbyaruleExaminationbeforelocationSealpropertyGaspressureduringtransportationwithgas0.01MPa~0.03MPaCheckthepressuregageTransportationwithoilNooilleakage,TopboltsaretightInspectionOilinsulationpropertyAccordancewiththespecificationsCheckthetestreportsPositioningofthetransformersCentrallinesofthebushingsandthebusductsMainUniformCheckbyaruleoraalto-meterWheelassemblyInstallationofthewheelsFlexiblePullInstallationofthestoppersFirmConnectionbetweenthesupportsandthetransformersSolidInspectionEarthofthetransformersMainFirmandconductiveRushvalueandnumberAccordancewiththemanufacturespecificationsCheckdependonthemanufacturespecificationsLocationassembliesontopoftheoiltanksWithoutdeformationandcrackInspection3.2.Evacuatenitrogen.Thepersonalmustnotgointothetransformeruntilcontentoftheoxygenexceed18%.3.3.Checkthetransformerbody3.3.1.Temperatureofthetransformerbodycanbehigher10℃thanambient.Theambienttemperaturecanbeabove0℃.3.3.2.Timeexposingtransformerbodycan’texceed16h.3.3.3.Tightenallboltsandtapes.3.3.4.Theironcoreshouldbeperfectandwithoutdamage.Insulationoftheironcoretogroundshouldbegoodafterdisconnectouterearthedwire.3.3.5.Thewindingsandtheoutletsshouldbeperfectandwithoutdamage.Connectionbetweentheoutletsandthebushingsshouldbecorrectandsolid.3.3.6.Thecontactofthetapswitchshouldbecorrectandtight.3.3.7.Cleanthetransformerbodywithqualifiedtransformeroilaftercheck.3.3.8.Qualitystandardscheckingtheoil-immersedtransformersareasshownintable3.3.8.Table3.3.8.:Examinationoftheoil-immersedtransformersItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationAppearanceofthetransformerbodiesPartsofthebodiesMainWithoutdeviationInspectionAppearanceofthepartsMainWithoutburn-out,damageanddeformationTiemeasuresonthepartsCompleteandtightPullInsulationboltsandpadsMainComplete,reliableandwithoutdamageCheckbyawrenchInsulationlayersofthewindingsandtheoutletsMainPerfectandsolidInspectionIroncoresEarthoftheironcoresMain1point,connectionisreliableInspectionInsulationoftheironcoresMainSupplyvoltage1min.bya2500Vmeg-ohm-meter,withoutflashingCheckbyameg-ohm-meterWindingsNakedconductorsAppearanceWithoutfragment,spew,breakandtwistInspectionWeldPerfectHighvoltagestressconeGoodInspectionOilpathWithoutimpurityGradingandshieldingcoversPerfect,withoutdamageFixtureofthewindingsMainSolidPullInsulationofthewindingsMainHigherthan70%ofthemanufacturevalueCheckbya2500Vmeg-ohm-meterTapchangersConnectionReliableInspectionSwitchcontactsCleanlinessandspringWithoutcorrosionandgrease,springisgoodInspectandpullContactMainReliableandtightCheckbya0.05mm×10mmgapgagePositionCorrectanduniformOperationexaminationPartassemblyCorrectandcompleteInspectionNo-loadtapchangersLengthoftheoperationrodsUniformforthreephasesInspectionAssemblyforturnFlexibleandsealOn-loadtapchangersOperationsequenceoftheswitchesMainCorrect,withoutopencircuitMeasurebyainstrumentSealoftheswitchesTightInspectionSealatinterfacebetweentheforcedoilcyclepipesandloweryokesTightInspectionCleanlinessMainWithoutimpurityandfragmentValveoperationCorrectandflexibleOperationexaminationCoverConnectionoftheflanges,forcesontheboltsTightanduniform,withoutoilleakageInspectandcheckbyatorquewrenchDurationexposingthetransformerbodiesinairMain<16h.Recorddurationtime3.3.9.Examinationrecordofthetransformerisasshownintable3.3.9.Table3.3.9.:ExaminationrecordofthetransformerProjectnameTypeRatedcapacityRatedvoltageRatedcurrentShortcircuitimpedanceWiringmannerCoolmannerTapchangingmannerOilweightManufactureManufacturingnumberManufacturingdateExaminationdateAmbienttemperatureRelativehumidityExaminationmannerExplosiondurationoftheironcoreDrainingoiltimeExhausttimeVacuumingtimeExaminationitemsResultsRemarkDismantletemporarysupportsWithoutdeformationofthebodiesTightboltsLockingmeasureoftheboltsInsulationboltsWithoutdeformationoftheironcoresInsulationpartsInsulationoftheironcorestogroundNumberofearthedpointsoftheironcoresInsulationbetweentheironcoresandscrewrodsoftheironyokesInsulationbetweentheironyokesandtheclampsInsulationbetweenthescrewrodsandtheclampsInsulationbetweentheironyokesanditssteeltapesInsulationoftheironcorescreensLayoutofthewindingsInsulationwrappingofthewindingoutletsOilpathsNakedpartsoftheoutletsWeldingoftheoutletsInsulationdistancesoftheoutletsConnectionbetweentheoutletsandthebushingsConnectionofthetapchangersConnectionofthetapsOperationofthetapchangersPositionofthecontactsOiltankbottomExaminationconclusionAcceptanceopinionSignatureDateConstructiongroupConstructionteamQualitydepartmentSupervisorydepartmentOwner3.4.Installationoftheattachments3.4.1.Sealoftheflangesmustbeperfectandtight.Shrinkagequantityofthesealedrubberscannotexceed1/3ofitsthickness.3.4.2.Operationofthetapchangersshouldbenormal,andindicationofthepositionindicatorshouldbecorrect.Qualitystandardsinstallingthetapchangersareasshownintable3.4.2.Table3.4.2.:InstallationofthetapchangersItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationNo-loadtapchangersTransmissionrodsCorrect,withoutblockTurnIndicatorsSealInspectionOn-loadtapchangersTappositionsandindicationsoftheindicatorsMainUniform,interlockandlimitarecorrectOperationexaminationSealoftheoilroomsGoodInspection3.4.3.Installtheoilforcedcoolersperfectly.Operatetheoilforcedcoolers30min.normallyandwithoutleakage.Installthefans,thevalves,theoilpipesandtheoilpumpscorrectly.Qualitystandardsinstallingthecoolersareasshownintable3.4.3.Table3.4.3.:InstallationofthecoolersItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationAppearancePerfect,withoutdeformationInspectionSealtestMainAccordancewiththemanufacturespecificationCheckthetestreportsRegulationofthesupportersandpullbarsMainFlangesurfacesareparallel,sealpadsinmiddleInspectionSinkingoilpumpsTightjointsFlowrelaysandpressuredifferencerelaysAccordancewiththemanufacturespecificationCheckdependonthemanufacturespecificationFansSolid,withoutdeformationInspectionValveoperationFlexibleoperation,correctpositionOperationPipesCleanwall,correctremarksInspection3.4.4.Installtheconservatorperfectly.Indicationoftheoillevelgaugeiscorrect.Qualitystandardsinstallingtheconservatorsareasshownintable3.4.4.Table3.4.4.:InstallationoftheconservatorsItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationInnerexaminationClean,withoutimpurityTouch,inspectionRubberbagsordiaphragmsClean,withoutdeformationanddamageInspectionSealoftherubberbagsordiaphragmsMainWithoutleakageBlowairslowlySealoftherubberbagsBreathe,withoutleakageInspectionExaminationoftheoillevelgagesCorrect3.4.5.Installthebushingsperfectly.Qualitystandardsinstallingthebushingsareasshownintable3.4.5.Table3.4.5.:InstallationofthebushingsItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationInstallationofthehighvoltagebushingsTestofthebushingsandthecurrenttransformersMainQualifiedCheckthetestreportsInstallationoftheturretsAppearanceexaminationWiringterminalsSolid,withoutoilleakageInspectionAirplugsTopoftheturretsPositionofinstallationCorrectInspectionInsulationtubeassemblyCorrectandappropriateConnectionwiththeflangesTightInstallationofthebushingsExaminationofthebushingsClean,normalforoillevelsandwithoutdamageInspectionConnectionboltsoftheflangesMainCompleteandtightCheckbyatorquewrenchInstallationoftheoutletsLaythewiresthroughthebushingsStraight,withouttwistingInspection220kVStressconesInthegradingcovers,depthisappropriate400kVGradingballsIntervalsareabout15mminthegradingcoversCheckbyaruleEqui-potentialcoppersheetReliableconnectionPullConnectionbetweentheoutletsandthebushingsMainTightbolts,tightsealInspectandcheckbyatorquewrenchInstallationofthelowvoltagebushingsExaminationofthebushingsClean,withoutdamageInspectionFlangeconnectionMainTightCheckbyatorquewrench3.4.6.Installthegasrelaysperfectly.Qualitystandardsinstallingthegasrelaysareasshownintable3.4.6.Table3.4.6.:InstallationofthegasrelaysItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationCalibrationMainQualifiedCheckthetestreportsInstallationoftherelaysCorrectposition,withoutleakageInspectionUpslopeoftheconnectionpipesMain1%~1.5%upslopealongoilstreamdirection3.4.7.Installthegasreliefvalvesperfectly.Qualitystandardsinstallingthesafetyairpathsandthegasreliefvalvesareasshownintable3.4.7.Table3.4.7.:InstallationofthesafetyairpathsandthegasreliefvalvesItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationInnerexaminationWithoutimpurityanddirtInspectionDiaphragmsPerfectConnectionbetweenthediaphragmsandtheflangesMainTight,isolatewithatmospherePositioncontactsofthediaphragmsAccurateoperationandgoodinsulationCheckbyamulti-meterPressuresofthegasreliefvalvesPositionCorrectInspectionCoversandspringsMainWithoutdeformationCheckelectriccontactsAccurateoperationandgoodinsulationCheckthetestreports3.4.8.Installthethermometersperfectly.Qualitystandardsinstallingthethermometersareasshownintable3.4.8.Table3.4.8.:InstallationofthethermometersItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationCalibrationofthethermometersAccordancewiththemanufacturespecificationCheckthecalibrationreportsMediumsinthesocketsandsealUniformwithoilinthetanks,tightsealInspectionCapillarytubesofthetemperaturebagsWithoutdeformation,curvatureradiusesaremorethan50mm3.4.9.Qualitystandardsinstallingthebreathersareasshownintable3.4.9.Table3.4.9.:InstallationofthebreathersItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationConnectionpipesClean,withoutblockInspectionOillevelsoftheoilglandsAtoilsurfacesSilica-gelCorrectcolor3.4.10.Qualitystandardsinstallingoilcleanersandwiringareasshownintable3.4.10.Table3.4.10.:InstallationoftheoilcleanersandwiringItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationInstallationoftheoilcleanersInnerexaminationClean,withoutimpurityanddirtInspectionExaminethefiltermeshesMainPerfectSilica-gelWhite,Oil-proofinsulationconductorsNeat,protectiveInspectionWiringboxesSolid,sealInstallationofthecontrolboxesSolidPull3.5.Drying3.5.1.Temperatureofthewallmustnotexceed110℃,thatofthebottom100℃,thatofthewindings95℃,foranoilimmersedtransformerwithoutoil.Temperatureofthecomingwindmustnotexceed100℃.Temperatureoftopoilmustnotexceed85℃withhotoil.3.5.2.Dryingfinishifinsulationresistancesofthewindingsmaintainconstant6hourfor110kVandbelowtransformer,12hourfor220kVandabovetransformer.3.6.Injectionoftheoil3.6.1.Mustcarryoutvacuumtreatmentfor220kVandabovetransformer.Temperatureofthetransformerbodycanexceed20℃.Thelimitvacuityisshowninthetable3.6.1.Table3.6.1:LimitvacuityoftransformerVoltage(kV)Capacity(kVA)Vacuity(MPa)354000~315000.05163~11016000andbelow0.05120000andabove0.08220and3300.101500<0.1013.6.2.Durationmaintainingvacuumcanbebeyond8hourfor220~330kVtransformerand24hourfor400kVtransformerbeforeoilinjection.3.6.3.Injectthequalifiedoilwhichtemperatureis50~60℃.Speedinjectingtheoilcannotexceed100L/min.3.6.4.Durationmaintainingvacuumcanbebeyond2hourfor110kVtransformerand4hourfor220kVandabovetransformerafteroilinjection.3.6.5.Mustcarryouthotoilcirculationwhichperiodcanexceed48hourfor400kVtransformerafteroilinjection.Temperatureofthehotoilatinletcanexceed50℃,thatintheoilboxexceed40℃.3.6.6.Durationstandingquietlycanexceed24hourfor110kVandbelowtransformer,48hourfor220kVand330kV,and72hourfor400kVafteroilinjection.3.6.7.Evacuateresidualgasfromthetransformer.3.6.8.Qualitystandardsinjectingoilareasshownintable3.6.8.Table3.6.8.:InjectionofthetransformeroilItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationInsulationoiltestMainQualifiedCheckthetestrecordsOiltemperatureHigherthanbodytemperatureMeasurebyathermometerBodytemperature>20℃VacuumdegreeMainAccordancewiththemanufacturespecificationCheckdependonthecodesVacuumdurationbeforeoilinjectionAccordancewiththemanufacturespecificationChecktherecordsInjectionspeedAccordancewiththemanufacturespecificationCheckbyaflowgageExaminationduringinjectionAccordancewiththemanufacturespecificationInspectionVacuumdurationafteroilinjectionAccordancewiththemanufacturespecificationCheckdependonthecodesExaminationofoillevelIndicationofoillevelCorrectInspectionLevelofoilsurfaceintheconservatorsMainAccordancewiththemanufacturespecificationHotoilcirculationof400kVtransformersOiltemperatureatoutletsoftheoilcleanersAccordancewiththemanufacturespecificationCheckbyathermometerTemperatureinoiltanksAccordancewiththemanufacturespecificationCirculationtimeAccordancewiththemanufacturespecificationChecktherecordsOilqualitytestafterhotoilcirculationMainQualifiedCheckthetestreports3.7.Cancarryoutthesealtestfortransformerwithoutleakage.Pressureontheoilboxtopis0.03Mpa.Durationoftestis24hour.Qualitystandardsofsealtestareasshownintable3.7.Table3.7.:SealtestofthetransformersItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationTestpressureAccordancewiththemanufacturespecificationCheckthepressuregageTesttimeAccordancewiththemanufacturespecificationChecktherecordsSealatweldseamsandjointsMainWithoutleakageInspection3.8.Oilinjectionundervacuumandsealtestrecordisasshownintable3.8.Table3.8.:OilinjectionundervacuumandsealtestrecordProjectnameTransformertypeRatedcapacityRatedvoltageRatedcurrentShortcircuitimpedance(%)WiringmannerCoolmannerTapchangingmannerOilweightManufactureManufacturingnumberManufacturingdateAmbienttemperature(℃)Relativehumidity(%)EarthofthetransformersExaminationandtestitemsResultsRemarkVacuumingIsolationoftheoilconservatorsIsolationofthesafetyairpipesPermittedvalueofvacuity(kPa)Maintainedvalueofvacuity(kPa)Maintainedtimeofvacuity(h)Bodytemperature(℃)OilinjectionundervacuumInsulationoiltemperature(℃)Withstandvoltageoftheinsulationoil(kV)tgδ(%)oftheinsulationoilWatercontentinoil(μg/g)Speedinjectingoil(L/min.)IntervalbetweenoilsurfaceandtanktopMethodofairexhaustionNumberofairexhaustionCirculationtimeofhotoil(h)Statictimeafteroilinjection(h)Pressureofsealtest(MPa)Durationofsealtest(h)VisualexaminationofthetransformerbodiesAcceptanceopinionSignatureDateConstructiongroupConstructionteamQualitydepartmentSupervisorydepartment3.9.Qualitystandardscheckingtransformerintegerareasshownintable3.9.Table3.9.:ExaminationofthetransformerintegerItemofexaminationPropertyQualitystandardsMethodsandtoolsforexaminationDataplatesandremarksofcircuitdiagramsDistinctandcompleteInspectionInstallationoftheattachmentsCorrectandsolidValvesoftheoilsystemOpen,correctindicationAppearanceofthetransformersClean,withoutimpurityonthetopsPositionandindicationofthetapchangersAccordancewiththeoperationrequirements,correctindicationsofthepositionsOillevelsMainNormalTemperaturemeasuringdevicesCorrectindicationGasrelaysMainSimulationtestsaregoodCheckthesimulationtestreportsCoolersGoodcommissioning,reliableinterlockInspectionFireproofequipmentsfordrainemergencyoilMainGoodandreliableOperationTestitemsMainQualifiedandcompleteCheckthetestreportsIntegersealMainWithoutoilleakageInspectionRemarksofthephasecolorsCompleteandcorrectEarthEarthedoutletbushingsoftheironcoresandclampersSolidandconductivePull,conductanceexaminationFinalscreensofthehighvoltagebushingsSparesecondaryterminalsofthecurrenttransformersEarthreliablyaftershortcircuitBodiesandfoundationsSolidandconductiveConnectionbetweentheleadsandthemainearthednetworksSolidandconductiveSealoftheholesTightInspection3.10.Thetransformershallbefinishedwithtwocoatsofbattle-shipgreysyntheticenamelpaintasperIS-5shade632.Thepaintshallbecarefullyselectedtowithstandtropicalheat,rainetc.Thepaintshallnotscaleofforcrinkleorberemovedbyabrasionduetonormalhandling.4.Test4.1.MeasureDCresistanceofthewindingsandthebushings4.1.1.Carryoutthemeasurementatalltapsofthetapswitch.4.1.2.Differenceofthemeasuredvaluesatthreephasewindingsshouldbelessthan4%ofthemeanvalueofthreephases,anddifferenceofthevaluesmeasuredbetweenthephaselinesshouldbelessthan2%ofthemeanvalueforathreephasetransformerwhichcapacityis1600kVAandbelow.4.1.3.Differenceofthemeasuredvaluesatthreephasewindingsshouldbelessthan2%ofthemeanvalueofthreephases,anddifferenceofthevaluesmeasuredbetweenthephaselinesshouldbelessthan1%ofthemeanvalueforathreephasetransformerwhichcapacityisabove1600kVA.4.1.4.ComparemeasuredDCresistanceswiththatinmanufactureratsametemperature.Differenceofthemcannotexceed2%.4.2.Checkthevoltageratiosofalltaps.Noobviousdifferenceandconsistwithregularityifcomparethevoltageratioswiththenameplatedataofthemanufacturer.Toleranceofthevoltageratioattheratedtappositionforthetransformerwhichvoltagelevelis220kVandaboveis±0.5%.4.3.Checkthevectorgroupofthreephasetransformerandthepolarityofsinglephasetransformerwhichmustconsistwiththemarksonthenameplates.4.4.Measurementofinsulationresistance4.4.1.Methodandsequence.Disconnectallwiresbetweenmeasuredequipmentandotherobjects,thendischargebymeansofearthedwire,theperiodofdischargingshouldexceed1min..Recordthetemperatureoftheequipment..Otherwindingswhicharen’tmeasuredmustbeshortcircuitandgrounded..Voltagelevelsofthemeg-ohm-metersformeasuringinsulationresistanceshouldaccordwiththefollowing:use250Vmeg-ohm-metersforelectricdevicesorcircuitswhichratedvoltagesarebelow100V,500Vmeg-ohm-metersfor100V~500V,1000Vmeg-ohm-metersfor500V~3000V,2500Vmeg-ohm-metersfor3000V~10000V,2500Vor5000Vmeg-ohm-metersfor10000Vandabove..AssumeR60s.orR1min.istheinsulationresistancemeasuredafter60seconds,R15s.isthatafter15seconds,R10min.isthatafter10minutes,thentheinsulationresistanceisR60s.orR1min,theabsorptionratioisR60s./R15s.,andthepolarizationindexisR10min./R1min...Theequipmentshouldbedischargedfullyintothegroundafterthemeasurement.Periodofdischargingshouldexceed2min.4.4.2.Themeasuredinsulationresistancemustexceed70%ofthatmeasuredinthemanufacturer.4.4.3.Measuretheabsorptionratioofthetransformerwhichvoltagelevelis35kVandabove,andthecapacityis4000kVAandabove.Themeasuredabsorptionratiocannotbelessthan1.3ornearthatinthemanufacturerin10~40℃range.4.4.4.Measurethepolarizationindexofthetransformerwhichvoltagelevelis220kVandabove,andthecapacityis120MVAandabove.Themeasuredpolarizationindexshouldbenearthatinthemanufacturer.4.5.Measurethetangentofdielectriclossanglei.e.tgδ(%)ofthewindingsandbushingsforthetransformerwhichvoltagelevelis35kVandaboveandthecapacityis8000kVAandabove.Themeasuredtgδ(%)mustnotexceed130%ofthatinthemanufacturer.4.6.MeasureDCleakagecurrentofthewindingsandthebushingsfor4.6.1.Thismeasurementmustbedoneforthetransformerof35kVandaboveinvoltageand10000kVAandaboveincapacity.4.6.2.RatedvoltageandratedcurrentofthetestersmeasuringDCleakagecurrentareasshowninthetable4.6.2.Table4.6.2:RatedvoltageandratedcurrentofthetesterTesteddevicesVoltage(kV)Current(mA)35kVpowercable220510kVandbelowpowercableandotherelectricdevices602Generator1005004.6.3.ReadandrecordtheDCleakagecurrentonhighvoltagebushingsat1min.aftersupplytestvoltage.ThetestvoltagemeasuringtheDCleakagecurrentforanoilimmersedpowertransformermustconsistwiththestandardsisshownasthetable4.6.3.Table4.6.3:TestvoltagestandardsmeasuringDCleakagecurrentRatedvoltageofthewinding(kV)6~1020~3563~330500DCtestvoltage(kV)102040604.6.4.MeasuredDCleakagecurrentforanoilimmersedpowertransformermustnotexceedthereferencevaluesshownasthetable4.6.4.Table4.6.4:ReferenceoftheDCleakagecurrentRatedvoltage(kV)PeakvalueofTestvoltage(kV)Leakagecurrent(μA)atfollowingtemperature(℃)10℃20℃30℃40℃50℃60℃70℃80℃2~351117253955831251786~15102233507711216625035620~352033507411116725040057063~3304033507411116725040057050060203045671001502353304.7.ACvoltagewithstandtest4.7.1.Methodandsequence.CapacityandvoltageoftheACvoltagewithstandtesterareasshowninthetable.Table:CapacityandvoltageofACvoltagewithstandtesterTesteddevicesCapacity(kVA)Voltage(kV)200~600MWgenerators12050/0.4125MWandbelowgenerators5035/0.435kVelectricdevices50100/0.420kVelectricdevices870/0.410kVelectricdevices535/0.4Lowvoltageelectricdevices110/.2.AssumeUisthetestvoltageinvolt,thenthewaterresistorR1inΩforprotectthetesteddevicemaybecalculatedbyformulaR1=K1U,whereK1=0.5~1Ω/V;thelimitresistorR2inΩforprotectthegapmaybecalculatedbyformulaR2=K2U,whereK2=1Ω/V..Raisethevoltageinno-loadtestafteradjustingthegapforover-voltageprotectioninordertothegapdischargewhenno-loadvoltagereaches1.1U,whereUistestvoltage.Thenraisevoltagetotestvalue,maintainitfor1min.Thegapshouldnotdischarge.Repeatthisoperationthreetimes..Thesettingoftheover-currentprotectionrelayis1.3timesthecapacitivecurrentathighvoltageside..Allnon-testedwindingsandcircuitsmustbeshortcircuitandgroundduringtest.Takeoffallelectronicdevices..Periodfromhalfofthetestvoltagetofullvaluecanbe10~15secondsandthefullvoltageshouldbemaintainedfor1min.Itshouldthenbereducedataratethatwillbringitto1/4valueorlessinnotmorethan15s.4.7.2.CancarryoutACvoltagewithstandtestofthewindingsandthebushingsforthetransformerwhichratedvoltagebelow110kV.4.7.3.TheACvoltagewithstandtestfortheoilimmersingtransformermustbecarriedoutafterstandquietlyindefiniteperiodandwithoutairbubblesintheoil.Theperiodstandingquietlymustexceed72hourfor400kVtransformer,48hourfor220~330kV,24hourfor110kVorconformtothemanufacturer’smanuals.4.7.4.Theinsulationresistanceafterthewithstandtestcannotbelowerthan70%ofthatbeforethetest.4.8.Partialdischargetest4.8.1.Methodofmeasuringthedischargequantity.Thetestpowersourcecanbeamediumfrequencygeneratorora150Hzpowersource..AssumeUisthevoltage