ApplicationsofAutomatedProtectiveRelayTesting

JoshLaBlanc

First,automatedprotectiverelaytesting….

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Whatisit?

Wherecanitbeapplied?

• PreventativeMaintenanceTesting– Theapplicationsareendlessanddependsonyourcompaniestestingprogram

• RelayCommissioning– End-to-EndTesting– TransformerTesting– BusDifferentialTesting

• NERCCIP– DataVerification

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Whatarethebenefits?

• Ifdesignedcorrectlycanreducehumanerror.• Cancompleterepetitive,boringtasksinaveryshortamountoftimeallowingtheendusertofocusmoreoftheirtimeintheareasthatneedattention.

• Canbeusedinmaintenancetestingtoprovideconsistencyintestingresultsformatting.

• Canuseautomationasapeercheckontheoverallprotectionsystem.

• Canperformrelaydataverification.(VeryusefulintheCIPrealm)

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HumanError

– Nobodymakesmistakes,right?

• CommonRelayMaintenanceTestingMistakes– Forgettingtoremoveofaprotectionsystemdevicefromserviceaspartoftestingisolation.

– Forgettingtotestanelementthatneedstesting.– Testingsomethingandforgettingtomarktheresults.– FlippedorbackwardswiringconnectionswhenperformingA/Dconvertertests.

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HumanError

• Examples– PMtestingLineCurrentDifferentialrelays….

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HumanError

• Examples– Commonelementsthatgetmissedduringtesting…

• RelayOutputs• RelayInputs• AuxiliaryRelays

– Howcantheseerrorsbeminimized?

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HumanError

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• Outputs

HumanError

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• AuxiliaryDevices

HumanError

• Examples–Whatifthetestingcircuitisincorrectlywired?

• Usingafewsimplecalculationsweknowwhattherelay’sresponse tocommoncircuiterrorsaregoingtobe.– ComparingPhaseRotation– ComparingSystemMagnitudes– Etc.

• Ifthesecalculationsindicateincorrectlywiredcircuits,theendusercanbeinformedbefore thetestingroutinearesenttoprintallowingthemtomakeadjustments towiringbeforeprinting.

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TimeisValuable• Howcantimebesaved?– GreenLight,RedLight….

• LoadChecks• InputTesting• OutputTesting• RelayStatusChecks• RelaySettingCompares• A/DConverter Testing

– Automatedtestingroutinescangrabinformationfromrelaysautomatically,thustheenduserdoesn’tneedtospendtimewritingitdown.• Automation isquicker, peoplearesmarter!

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TimeisValuable• GreenLight,RedLightPrinciple

Thishasafailureinit!

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TimeisValuable• GreenLight,RedLightPrinciple

Thisdoesnot!

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TimeisValuable• LoadChecks

– Whenverifyinglegitimacyofaloadcheck,theengineeringbrainismakingalotoflogicaldecisions.

– Whynotuselogicinautomationtofilteronlytheloadcheckresultsthatneeddetailedinvestigation.

– 90%ofloadcheckscanbeverifiedtobesatisfactorybysimpleautomationlogic.

– Theremaining10%areflaggedandverifiedbyanengineer• Automation isquicker, peoplearesmarter!

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TimeisValuable• LoadCheckFiltering,3-PhaseApplications

– Comparephaserotationonbothcurrentandvoltage.– Comparephaseangledisplacementiscloseto120°.– Comparemeteredvoltagemagnitudestothenominalvalue.

– Comparemeteredcurrentmagnitudestoverifytheyareroughlybalanced.

– Verifythecircuitpowerfactorisaboveanacceptablelevel.

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TimeisValuable• RelaySettingsCheckExample(3-PhaseRoutine)– Isthisafailure?

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• Notnecessarily

TimeisValuable

• LoadCheckFiltering,SinglePhase– Comparemeteredvoltagemagnitudestothenominalvalue.

– Comparemeteredneutralvoltagemagnitudestoverifytheyarenon-zerobutsubstantiallylarge.

– Comparemeteredneutralcurrentmagnitudestoverifytheyarenon-zerobutsubstantiallylarge.

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TimeisValuable• LoadCheckFiltering,DifferentialSchemes

– Whynotmeterthedifferentialelement?– Shouldseeminimaloperatecurrentandsubstantialrestraintcurrent!

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TimeisValuable

• LoadCheckFiltering,Sync– Comparemeteredvoltagemagnitudestothenominalvalue.

– Comparemeteredphaseangledisplacementtoverifyminimaldisplacementbetweenthetwosources.

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TimeisValuable• RelaySettingsCheckExample(SyncRoutine)– Cananyoneseetherelaysettingsproblem?

• RelayisaSEL-421• 115kVNominalSystem• PTRY=1000(Corresponds toVpmag)• PTRZ=600(Corresponds toNVS1mag)

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TimeisValuable• RelaySettingsCheckExample(SyncRoutine)– Cananyoneseetherelaysettingsproblem?

• TherelaysyncelementKS1Msettingwassentto1.• PerSEL-421logic,PTratiosshouldbeaccounted forinthesetting,therefore itshouldhavebeensetto1.66.

• Automatedchecksprevented abreaker reclosing failure.

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FormatConsistency

• Auditorsloveformattingconsistencies!– Automationguaranteesthetestingresultsforeachparticularelementareprintedthesameevery time.

– Testingresultsformatsarenotdependentoneachindividualsdocumentationmethods.

– Consistentformatsaremucheasiertoprovideanengineeringreviewascomparedresultswithformattinginconsistencies.

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CommissioningPeerCheck• Delta-WyeTransformerTesting

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CommissioningPeerCheck• ThingstoconsiderwhencommissioningaDelta-WyeTransformerRelay– Howarethedeltawindingsofthetransformerinternallyconnected?DABorDAC?

– Howarethetransformerdeltawindingsexternallyconnectedtothepowersystem?ABCorACB?

– HowaretheCTsconnected?Samepolarityoropposingpolarity?

– CTratios?– TransformerTurnsRatio?

• GatheringData– AlwaysformulatequestionssothatyouaretestingthesystemandNOTtherelay!

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CommissioningPeerCheck• TransformerExampleQuestions– Fromthetransformernameplate,howarethedeltawindingsinternallyconnectedtooneanother?

– Fromthesystemthreelinediagram,howarethetransformer’sdeltawindingsconnectedtothepowersystem?

– Fromthesystemthreelinediagram,arethedifferentialrelay’scurrenttransformersconnectedinopposingorthesamepolarity?

– Fromthesystemthreelinediagram,whataretheratiosoftheprimaryandsecondarycurrenttransformerratiosusedinthedifferentialscheme?

– Fromthetransformernameplate,whataretheoperatingprimaryandsecondaryvoltagesofthetransformer?

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CommissioningPeerCheck• Delta-WyeTransformerTesting– Themostimportanttestisathroughlinetogroundfaultofthetransformer.

– Withminimaloperateandsubstantialrestraintcurrentduringthistest,thecorrecttransformervoltageandcompensationangleisconfirmed.

– Notethatthewaythistestissetup,theprotectionsystemwastestedandnottheprotectiverelay!• Ifrelaysettingsareusedasinputsintothetestsetup,youareonlytestingthattherelaybehavesaccordingtohowyouhaveprogrammed it.Thisisn’tmuchdifferent thananA/Dconverter testduringapreventativemaintenance test.

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CommissioningPeerCheck

• TransmissionLineEnd-to-EndTesting– Again,teststheprotectionsystemandnottherelay!– FaultquantitiescanbeexportedoutofpowersystemmodelingsoftwaretobeusedasrealtimefaultsimulationwhenperformingEnd-to-Endtesting.

– ThetransmissionlinerelaycommunicationschemeisreallybeingtestedinatransmissionlineEnd-to-Endtest.• Careshouldbetakenwhendecidingwhere toplacefaultsforsimulationinthemodelingsoftware.

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CommissioningPeerCheck

• TransmissionLineEnd-to-EndTesting– AutomationcanbeusedonrelaystoautomaticallysavetherelaySER’storesultswhichinturnspeedsuptesting.

– Whenusingautomationduringtesting,theusershouldpayattentiontoeverydevicetoverifythecorrectoperationofeachdeviceduringthetests.

– TheusershouldthenreviewtheSERssavedwitheachtesttoverifythecorrectrelaylogicoperations.

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CIP• WhatbenefitcanautomationhaveinCIP?– CIPisextremelyinformation,comparison,andtrackingintensive.

– AutomationcanperformalargeamountofthemindnumbingtasksCIPrequires!• Automated routinescancompare relayinformationtoverifynodiscrepancies whereexpected.

• Automated routinescantelltheenduser thepasswordcomplexityallowedfromthedevicesimplybygatheringandanalyzingtherelayfirmwarestring.

• Automationcangatherandprintalltherelayportsettingsusingterminalprograms.

• Relayinformationcanbeautomaticallyupdated toarelaynameplateinthesystemdatabasebysimplyusingimportfunctions.

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CIP• DataVerificationExample

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CIP• CIPFlowDiagram

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LessonsLearnedandAdvise• LessonsLearned– Haveanoverallvisionandsticktothatvision.– Gatherallpossibilitiesofapplicationoftherelaybeforescriptingthetestingroutine.

– Whenfirstusingatestingroutine,printmoretoresultsthanneeded.Ithelpsfordebuggingifprogramerrorsoccur.

– Whencreatingroutines,therewillbebugsjustgetusedtoitandbeproactiveinfixingthem.

– Startwiththehardestroutine.Often,partsofthisroutinecanbecopiedtootherroutines.

– Automatedtestingroutinescanalwaysbemadebetter.Beacceptingofconstructivefeedback.

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LessonsLearnedandAdvise

• Advise– Theprogrammershouldhaveasolidfamiliarityofathreephasepowersystem.

– Askthetesterforfeedbackwhereverpossible,especiallyifprogrambugsarefound.Thetesterisyourbesthelp!

– Havefamiliarityoftheentireautomatedprocess.

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Questions?

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