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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