翻译打印.docx

翻译打印.docx

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翻译打印

Features

Integratedthree-phasedifferentialrelay,over-currentrelayandearth-faultrelayStabilizedthree-phasedifferentialrelayprovidingwindingshort-circuitandinterturnfaultprotectionfortwo-windingtransformersandgenerator-transformerunitsandwindingshort-circuitprotectionforgenerators

Earth-faultprotectionfortransformerHVandLVsidewindingsaccordingtothedesiredprinciple:

thestabilizeddifferentialcurrentprinciple,thehigh-impedanceprinciple,thecalculatedormeasuredresidualcurrentprincipleortheneutralcurrentprinciple

Three-stageovercurrentprotectionfortransformersandgeneratorsandtwo-stageback-upprotectionforearth-faultprotection

Theoperationcharacteristicofthedifferentialrelayeasilyadaptedfordifferentapplications

Shortoperatetimes,evenwithpartiallysaturatedcurrenttransformers

Stabilizationpreventsunwantedoperationsatfaultsoutsidetheprotectedareaandtransformerinrushcurrents

Blockingbasedontheratioofthesecondharmonicandthefundamentalcomponentofthedifferentialcurrentpreventsunwantedoperationsattransformerinrushcurrents

Blockingbasedontheratioofthefifthharmonicandthebasicfrequencycomponentofthedifferentialcurrentpreventsoperationinharmlesssituationsoftransformeroverexcitationcanbeeliminatediftheratioofthefifthharmonicandthebasicfrequencycomponentincreasesathighovervoltages

Nointerposingtransformersareneededfortheprotectionoftwo-windingtransformers-numericalvectorgroupmatchingonHVandLVside

WideCTratiocorrectionrange-accuratecorrectionallowedbydigitalsetting

Sensitivephasecurrentandphaseangledisplaysfacilitatethecheckingofmeasurementcircuitconnectionandvectorgroupmatching

Fourtripandfoursignalrelayoutputsavailabletotheprotectiondesignengineer

Fiveprogrammableexternalcontrolinputsintendedfortheindicationandretransmissionofalarmandtripsignalsofgasrelays,oiltemperaturesensorsandothersensorsoftransformerauxiliarydevices

AdjustableCBFPoperatetimetoimprovereliabilityofoperation

Integrateddisturbancerecordercapableofrecordingcurrentsanddigitalsignals-signalstobeusedfortriggeringselectable

Highimmunitytoelectricalandelectromagneticinterferenceallowstherelaytobeusedinsevereenvironments

Highavailabilityandsystemreliabilityduetocontinuoussupervisionofhardwareandsoftware

Application

ThestabilizeddifferentialrelaySPAD346Cisdesignedtobeusedtoprotecttwo-windingtransformersandgenerator-transformerunits

againstwindingshort-circuit,interturnfault,earthfaultandshortcircuitandtoprotectgeneratorsagainstwindingshort-circuitandshortcircuit.Therelaycanalsobeusedfortheprotectionofathree-windingtransformerprovided75%oftheshortcircuitpowerisfedfromthesamedirection

Descriptionofoperation

TheintegrateddifferentialrelaySPAD346Cincludesthreeindependentrelaymodules:

athree-phasestabilizeddifferentialrelaymoduleSPCD3D53,anearth-faultrelaymoduleSPCD2D55andacombinedovercurrentandearthfaultrelaymoduleSPCJ4D28.Theratedcurrentsoftherelayare1Aand5A.TheHVandLVsidemayusethesameordifferentratedcurrents.

Belowashortdescriptionofthefeaturesoftheprotectionrelaymodules.Themanualsfortheseparaterelaymodulesdescribethemodulesmoreindetail.

Three-phasestabilizeddifferentialrelaymoduleSPCD3D53

ThedifferentialrelaymoduleSPCD3D53providesprotectionforwindingshort-circuitandinterturnfaults.Thedifferentialrelaycomparesthephasecurrentsonbothsidesoftheobjecttobeprotected.Shouldthedifferentialcurrentofthephasecurrentsonbothsidesoftheobjecttobeprotected.Shouldthedifferentialcurrentofthephasecurrentsinoneofthephasesexceedthesettingofthestabilizedoperationcharacter-isticortheinstantaneousprotectionstageofthemodule,themoduleprovidesanoperatesignal.

Differentamplitudesorphasedifferenceofthecurrentsmaybethereasonforthedifferentialcurrent.formerstoobtainvectorgroupmatchingandtomatchthesecondarycurrentsofthemaintransformers.InterposingCTshavealsobeenusedtoeliminatethezero-sequencecomponentsofthephasecurrentsatearthfaultsoccurringoutsidetheprotectedarea.ThedifferentialcurrentrelaySPAD346Celiminatestheuseofinterposingtransformersfortheprotectionoftwo-windingtransformersasthedifferentialrelaymoduleallowsthetransformervectorgroupmatching,theCTratiocorrectionandtheeliminationofthezero-sequencecomponentofthephasecurrentstobedigitallyimplementedontheHVand/ortheLVside.

Stabilizeddifferentialcurrentstage

InpowertransformerprotectiondifferentialcurrentiscausedbyCTerrors,varyingtapchangerpositions,transformerno-loadcurrent,transformerinrushcurrents,transformeroverexcitationinovervoltageandunderfrequencysituations,andCTsaturationathighcurrentspassingthroughthetransformer.Dif-ferentialcurrentcausedbyCTerrorsandtapchangerpositiongrowsatthesamepercentratioastheloadcurrentincreases.IntheprotectionofgeneratorsthedifferentialcurrentiscausedbyCTerrorsandsaturationoftheCTsinsituationswherehighcurrentspassthroughthetransformer.

Highcurrentspassingthroughtheobjecttobeprotectedmaybecausedbyshortcircuitsoutsidetheprotectedarea,largecurrentsfedbythetransformerorthegeneratorinmotorstart-uportransformerinrushsituations.Duetothesecircumstancestheoperationofthedifferentialrelayhasbeenstabilizedinrespectoftheloadcurrent.Inastabilizeddifferentialrelaythedifferentialcurrentrequiredforrelayoperationishigher,thehighertheloadcurrentis.Thestabilizedoperationcharacteristicofthedifferentialrelaymoduleandthesettingrangeofthe

characteristicispresentedinthedescriptionofthedifferentialrelaymoduleSPCD3D53.

TheoperationofthedifferentialrelaymoduleSPCD3D53isbasedonthefundamentalfrequencycomponents.Operationbasedonfundamentalfrequencycomponentsisaccurateandstable:

theDCcomponentandharmonicsofthecurrentdonotcauseunwantedoperationoftheprotectionstage.

Blockingbasedonthesecondharmonicofthedifferentialcurrent

transformermagnetizinginrushcurrentsoccurwhenenergizingthetransformerafteraperiodofdeenergization.Theinrushcurrentmaybe

manytimestheratedcurrentandthehalvingtimemaybeuptoseveralseconds.Tothedifferentialrelayinrushcurrentrepresentsdifferentialcurrent,whichwouldcausetherelaytooperatealmostalwayswhenthetransformerisconnectedtothenetwork.Typically,theinrushcurrentcontainsalargeamountofsecondharmonics.BlockingoftheoperationofthestabilizedstageoftherelayatmagnetizinginrushcurrentisbasedontheratiooftheamplitudesofhesecondharmonicdigitallyfilteredromthedifferentialcurrentandthefundamentalfrequencyId2f/Id1f.

Theblockingalsopreventsunwantedoperationatrecoveryandsympatheticmagnetizinginrush.Atrecoveryinrushthemagnetizingcurrentofthetransformertobeprotectedincreasesmomentarilywhenthevoltagereturnstonormalafterclearanceofafaultoutsidetheprotectedarea.Sympatheticinrushiscausedbyatransformer,whichrunsinparallelwiththeprotectedtransformeralreadyconnectedtothenetwork,beingenergized.

Theconnectionofthepowertransformeragainstafaultinsidetheprotectedareadoesnotdelaytheoperationoftherelaymodule,becauseinsuchasituationtheblockingbasedonthesecondharmonicofthedifferentialcurrentispreventedbyaseparatealgorithmbasedonthewaveformandtherateofchangeofthedifferentialcurrent.

Blockingbasedonthefifthharmonicofthedifferentialcurrent

InhibitionofrelayoperationinsituationsofoverexcitationisbasedontheratioofthefifthharmonicandthefundamentalcomponentofthedifferentialcurrentId5f/Id1f.Atdangerouslevelsofovervoltagewhichmaycausedamagetothetransformer,theblockingcanbeautomaticallyeliminatedbyaseparateblockinginhibitingsettingId5f/Id1f>>.Whenrequired,theblockingbasedonthesecondandfifthharmonicofthedifferentialcurrentcanbedisabled.

Instantaneousdifferentialcurrentstage

InadditiontothestabilizedstagethedifferentialrelaymoduleSPCD3D53hasaseparateadjustableinstantaneousstagetheoperationofwhich

isnotstabilized.TheinstantaneousdifferentialcurrentstageoperateswhenthefundamentalcomponentcalculatedfromthedifferentialcurrentexceedsthesetoperatelimitId/In>>orwhentheinstantaneousvalueofthedifferentialcurrentexceedsthelevel2.5xId/In>>.ThesettingrangeoftheinstantaneousstageId/In>>is5...30.Shouldthestabilizingcurrentbelessthan30%ofthedifferentialcurrent,thereismostcertainlyafaultintheprotectedarea.InsuchasituationthesetoperatevalueId/In>>willbehalvedandtheblockingsofthestabilizedstageareautomaticallyprevented.

Disturbancerecorder

ThedifferentialrelaymoduleSPCD3D53isprovidedwithanintegrateddisturbancerecorderthatiscapableofrecordingsixphasecurrents,theinternaltripandblockingsignalsofthemoduleandthecontrolinputsignals.Recordingcanbetriggeredbytherisingorfallingedgeofthesesignal.Therecordinglengthis38cycles.Therecordingmemoryhasthecapacityofstoringonerecordingatatime.Samplingfrequencyis40samples/cycle.TherecordingisdownloadedbyusingaPCprogram.Therecordingmemoryhastoberesetbeforeanewrecordingispossible.

Earth-faultrelaymoduleS