ICS27.100P62RecordNo.J150—2002ElectricPowerIndustryStandardofthePeople’sRepublicofChinaP DL/T5147—2001DesigningRulesforSecurityandAutomaticityEquipmentofPowerSystemIssueDate:December26,2001 ImpIementationDate:May1,2002IssuedbytheStateEconomicandTradeCommissionofthePeopIe’sRepubIicofChinaElectricPowerIndustryStandardofthePeople’sRepublicofChinaP DL/T5147—2001DesigningRulesforSecurityandAutomaticityEquipmentofPowerSystemDraftedby:NortheastElectricPowerDesignInstituteofStatePowerCorporationApprovedby:StateEconomicandTradeCommissionofthePeople’sRepublicofChinaApprovalDocumentNo.:No.31AnnouncementIssuedbyStateEconomicandTradeCommissionofthePeople’sRepublicofChinain2001Translationsponsoredby:ChinaElectricPowerPlanning&EngineeringAssociationTranslatedby:SUNTHERConsultingCo.,Ltd.Reviewedby:NortheastElectricPowerDesignInstituteofStatePowerCorporationCHINAELECTRICPOWERPRESSBEIJING,2001圖書在版編目（CIP）數(shù)據(jù)DL/T5147—2001電力系統(tǒng)安全自動裝置設(shè)計技術(shù)規(guī)定：英文/中華人民共和國國家經(jīng)濟貿(mào)易委員會發(fā)布.—北京：中國電力出版社，2013.5ISBN978-7-5123-4404-4Ⅰ.①D…Ⅱ.①中…Ⅲ.①電力系統(tǒng)安全裝置自動裝置設(shè)計規(guī)范中國英文Ⅳ.①TM77465中國版本圖書館CIP數(shù)據(jù)核字（2013）第089398號中國電力出版社出版（北京市東城區(qū)北京站西街19號100005）北京博圖彩色印刷有限公司印刷*2013年5月第一版 2013年5月北京第一次印刷850毫米×1168毫米32開本1印張21千字敬告讀者本書封底貼有防偽標(biāo)簽，刮開涂層可查詢真本書如有印裝質(zhì)量問題，我社發(fā)行部負(fù)責(zé)退版權(quán)專有 翻印必究DL/T5147—2001ContentsForeword ⅡScope 1NormativeReferences 2General 3andDefinitions 6PrincipleforCalculationandAnalysisofSecurityandStabilityofPowerSystem 9MainControlModeofSecurityandAutomaticityEquipment 14ConfigurationandCompositionofSecurityandAutomaticityEquipment 19Aofinthe23IDL/T5147—2001ForewordTheserulesarepreparedinresponsetotheNoticeonPlannedProgramsofScientificResearch,StandardizationandInformationforElectricPowerSurveyandDesignin1995issuedbytheElectricPowerPlanningandDesignGeneralInstituteofStatePowerCorporation.Theyarepreparedthroughextensiveinvestigations,referencetosimilardomesticandinternationalstandardsandseekingcommentsfromtheorganizationsandexpertsintheelectricpowerindustryinChina.TheserulesareinlinewiththeprinciplesspecifiedinGB14285—1993CodeforRelayingProtectionandSecurityAutomaticEquipment,SD131—1984GuidelinesforPowerSystem(trial)issuedbytheMinistryofResourcesandElectricPower,andDL755—2001GuideonSecurityandStabilityforPowerSystem,andispreparedforthedesignofsecurityandautomaticityequipmentofpowersystem.AppendixAtotheserulesisinformative.TheserulesareproposedbytheTechnicalCommitteeonElectricPowerPlanningandEngineeringofStandardizationAdministrationofPowerIndustry.TheserulesareunderjurisdictionoftheTechnicalCommitteeonElectricPowerPlanningandEngineeringofStandardizationAdministrationofPowerIndustry.ThedraftingorganizationofthisstandardisNortheastElectricPowerDesignInstituteofStatePowerCorporation.ThemaindraftersoftheserulesincludeZhangYouandZuoIIChangchun.

DL/T5147—2001TheserulesareexplainedbytheTechnicalCommitteeonElectricPowerPlanningandEngineeringofStandardizationAdministrationofPowerIndustry.TheserulesaretranslatedbySUNTHERConsultingCo.,Ltd.undertheauthorityofChinaElectricPowerPlanning&EngineeringAssociation.IIIDL/T5147—20011 ScopeTheserulesstipulatetheprincipledrequirementsoncalculationandanalysisofsecurityandstabilityofpowersystem,designandconfigurationofsecurityandautomaticityequipmentduringthedesignofpowersystemandareapplicabletothedesignofsecurityandautomaticityequipmentofpowersystem,thedesignofsecurityandautomaticityequipmentnecessaryforconnectingpowerplantsandsubstationstopowersystemaswellasthestudyonconfigurationschemesofsecurityandautomaticityequipment.1DL/T5147—20012 NormativeReferencesThefollowingnormativereferencescontainprovisionswhich,throughreferenceinthistext,constituteprovisionsoftheserulesfordatedreferences,subsequentamendmentsto(excludingerrorcorrections),orrevisionsof,anyofthesepublicationsdonotWhentheserulesarepublished,therevisionsshownhereinareinforce.However,partiesenteredintoagreementsbasedonthiscodeareencouragedtoinvestigatethepossibilityofapplyingthemostrecenteditionsofthenormativedocumentsindicatedForundatedreferences,thelatesteditionsthereofshallGB14285—1993TechnicalCodeforRelayingProtectionandSecurityAutomaticDevicesDL/T559—1994 CodeforOperationSettingsofRelayProtectionEquipmentin220-500kVPowerGridsDL428—1991TechnicalRulesforAutomaticLowFrequencyLoadSheddingofPowerSystemDL755—2001GuideonSecurityandStabilityforPowerSystemSD131—1984TechnicalGuidelinesforPowerSystem(trial)2DL/T5147—20013 General1ThedesignofsecurityandautomaticityequipmentofpowersystemshallcomplywiththerequirementsofDL755—2001GuideonSecurityandStabilityforPowerSystem.Thesecurityandautomaticityequipmentofpowersystemcanbeclassifiedintothefollowingcategoriesbytheirfunctionalapplications:equipmenttoautomaticallypreventlossofstability,equipmenttoautomaticallyeliminateasynchronousoperation,equipmenttoeliminatefrequencyorvoltagedeviationsthatmayleadtoaccidentevolvementordamagestoequipment,andequipmenttorestorenormaloperationofpowersystem.Thesecurityandstabilitycontrolsystemofpowersystemismainlyintendedtopreventlossofstabilityofpowersystemandavoidthesystemaccidentsofpowersystem,suchaslarge-scaleblackouts.2Thesecurityandautomaticityequipmentofpowersystemshouldpreferablyemploysimple,reliable,provenandeffectiveequipmentthataredeployedinadistributedequipmentintendedfordifferentcontrolledobjectsshallbeabletoworkcollaboratively.3Thehardwareofpowersystemstabilitycontrolequipmentshallbeuniversaltoacertaindegree,whileitssoftwareshallbemodularizedtoallowforthesystemevolvement.4AproperpowergridstructurethatmeetstherequirementsinSD131—1984TechnicalGuidelinesforPowerSystem(trial)andDL755—2001GuideonSecurityandStabilityforPowerSystem3DL/T5147—2001providesanimportantphysicalguaranteeforthesafeandstableoperationofpowersystem.Undernormalpowergridstructureconditions,theconventionalmeasuresforimprovingthestabilityaresufficienttoguaranteethesafeandstableoperationofpowersystemunderasinglefaultcondition.However,inordertodealwithmultiplefaultsthatmaygiverisetodetrimentalcascadingresponseswhichresultinamajoraccidentacrossthepowergrid,apropergridstructuremustbeestablished,accompaniedwiththenecessaryautomaticcontrolmeasuresforensuringsystemsecurityandstability.5Whenestablishingtheguidingstrategyforaddressingthesecurityandstabilityproblemsofpowersystem,itisnecessarytomakeprovisionsforthemostseveresituationsthatmayariseandtakepre-establishedmeasuresaspracticalaspossibleinordertopreventsystemcollapse,extendedlarge-scaleblackoutsandcatastrophicblackoutsaffectingmajorusers(includingpowerplantswheretheauxiliarypowerisessential),reducethepowerloadlesstotheminimumandrestorethesystemtonormaloperationfollowingasevereaccident.preventfurtherdeteriorationofthesystemconditions,itisimperativetotakeactionstoprotectthewholesystemattheexpenseofthelossoflocalsystemstherebyavoidingthesignificantdamagetothesystem.6Asthecorrectoperationofrelayprotectionequipmentandfastfaultclearingareessentialforthesafeandstableoperationofpowersystem,effortsshallbemadetoimprovetheoperationperformanceoftherelayprotectionequipmentsoastoimprovethestabilitylevelofpowersystem.7Whenselectingtheconfigurationschemeofsecurityandautomaticityequipmentofpowersystemandinordertoassesstheeconomicalbenefitsoftheseequipmentthatareprovidedandputinto4DL/T5147—2001service,oneshallgivemoreconsiderationtothecorrectfunctioningoftheseequipmentwhichisessentialforimprovingthestabilitylimitofpowersystem,increasingthepowertransmissioncapacityandguaranteeingboththesocialandeconomicalbenefitsresultingfromsupplyingelectricpowertousersuninterruptedlywhicharetobecomparedwiththerequiredinvestmentcostsoftheseequipment.5DL/T5147—20014 TermsandDefinitions4.1SecurityandAutomaticityEquipmentofPowerSystemAnautomaticprotectiondevicewhichcanpreventthelossofstabilityofpowersystemandavoidlarge-scaleblackoutsinpowersystem,includingauto-reclosingdeviceontransmissionlines,powersystemstabilitycontroldevice,automaticpowersystemsplittingdevice,lowfrequencyloadsheddingdevicesandundervoltageloadsheddingdevices.4.2StabilityControlDeviceofPowerSystemAnintegratedautomaticdevicewhichcanautomaticallyprotectthepowersystemfromlossofstability.Thepowersystemstabilitycontroldevicescanbeofdistributedorcentralizedstructures.Distributeddevicescanprocessthelocalinformationandmakedecisions,ortransmitcommandsviaadditionalchannelstoachievelocalorremotecontrol.Forcentralizeddevices,inadditiontothelocalinformation,theycancollecttherelevantinformationatotherpointsthroughinformationchannelsandcomprehensivelyprocesssuchinformation,makedecisions,issuecontrolcommandslocallyortootherpointsviainformationchannels.4.3AutomaticSplittingDeviceofPowerSystemAdevicewhichcanautomaticallydisconnectthepowersystematpredeterminedsuitablesitesinaplannedway,orautomaticallydisconnectapowerplantanditsloadfromthemainpowersystem6DL/T5147—2001appropriatelysoastodampoutthepoweroscillationintheeventofout-of-steposcillation,collapseoffrequencyorvoltageofpowersystem.Dependinguponthenatureofthesystemaccidentsandtheapplicationconditionsandinstallationsitesofthedevices,thepowersystemautomaticsplittingdevicescanbeclassifiedintothreecategories,namely,oscillationsplittingdevice,(high/low)frequencysplittingdeviceandundervoltagesplittingdevice.4.4LowfrequencyLoadSheddingDeviceAdevicewhichcanautomaticallyswitchoffsomepowerconsumingloadstorapidlyrestorethefrequencytobewithinthepermissiblerangetherebyavoidingthefrequencycollapseintheeventthataccidentsoccurinthepowersystemleadingtorapidandsignificantdropoffrequency,alsoreferredtoasautomaticlowfrequencyloadsheddingdevice.4.5UndervoltageLoadSheddingDevicesAdevicewhichcanautomaticallyswitchoffsomeloadstorestoretheoperatingvoltagetobewithinthepermissiblerangeinordertopreventvoltagecollapseduetoinsufficientreactivepowercompensationfollowingaccidentsorwhenloadincreasestoexceedthepredictedvalue.4.6Auto-reclosingAnautomaticoperationcycleinwhich,afteroverheadlinesorbusbararedisconnectedduetofaults,theopenedcircuitbreakerisautomaticallyclosedafterapresetshort-timedelaytoenergizethede-energizedpowercomponentsoncemore;ifthefaultsstillpersist,theprotectiondeviceswilloperatetoopenthecircuitbreakeronce7DL/T5147—2001more.Itmainlyconsistsofthree-phasereclosing,single-phasereclosingandsyntheticreclosing.4.7MeasuresinSecondarySystemtoImprovePowerSystemStabilityAgeneraltermforalltypesofautomationmeasureswhicharetakentoimprovestableoperationofpowersystemthroughoperatingtheautomaticdevicestocontrolandadjusttheoperationstatusofpowercomponentsandequipmentintheeventofemergenciesoraccidents.Thesemeasuresincludefastfaultclearing,generatortripping,rapidreductionofoutputofprimemoversofthermalpowerunits,electricalbraking,quick-responseexcitationofgeneratorsandconcentratedloadshedding.4.8DisturbanceAsuddengreatandsubstantialchangeinstatusofpowersystemduetoshortcircuitingorunscheduledtrippingofsystemcomponents.4.9ConnectionandPowerSectionConnectionreferstoacombinationofpowergridcomponents(forexample,transmissionlinesandtransformers)thatareusedtoconnecttwopartsofthepowersystem.Theconceptofconnectionmayalsoinvolveintermediatepowerplantsandkeyloadpoints.Apowersectionreferstooneormorethanoneconnectioncomponent,which,oncedisconnected,causethepowersystemtobeseparatedintotwoindependentparts.8DL/T5147—2001 PrincipleforCalculationandAnalysisofSecurityandStabilityofPowerSystem1OperatingModeforStabilityCalculationWhencalculatingandanalyzingthestabilityofpowersystem,theoperatingmodethatisthemostunfavorabletothestabilityshallbeselectedfromthefollowingthreemodesforcheckingthestabilityofthespecificobjects(forexample,linesandbusbar).1NormalOperatingMode2Post-faultOperatingModePost-faultoperatingmodereferstotheshort-timesteady-stateoperatingmodethatoccursbeforethepowersystemrestorestonormaloperationfollowingfaultclearing.3SpecialOperatingMode2FaultforStabilityCalculation1I(SingleMinorFaults)lSuccessfulreclosingofanylinesfollowingsingle-phasetransientgroundfaults;9DL/T5147—2001Incaseofdoublecircuitsormultiplecircuitsoflinesatthesamevoltagelevel,unsuccessfulreclosingofanycircuitfollowingsingle-phasepermanentgroundfaultsandthreephases’failuretorecloseafterbeingdisconnectedwithoutanyfaultoccurring;Trippingorlossofexcitationofanygeneratorunit;Suddenchangeinanylargeloadinthesystem(suchasimpulseloadorsuddenswitchingoffofalargeload).2II(SingleSevereFaults)Single-circuitlines’unsuccessfulreclosingfollowingsingle-phasepermanentgroundfaultandthreephases’failuretorecloseafterbeingdisconnectedwithoutanyfaultoccurring;Busbarfaults;Incaseofanelectromagneticloopnetworkattwovoltagelevels,faultofsingle-circuitlinesathighervoltagelevelorthreephases’failuretorecloseafterbeingdisconnectedwithoutanyfaultoccurring;Incaseofdoublecircuitsoflineserectedonthesametower,twophaseswithdifferentdesignationsfailtoreclosefollowingsimultaneoussingle-phasegroundfaults,orsimultaneoustrippingofdoublecircuits;Anysinglelineaccountingforalargeproportionofsystemcapacityortrippingorlossofexcitationofgeneratorunits;Three-phaseshort-circuitingofoutgoinglinesofpowerplants.3FaultClearingTimeforStabilityCalculationFaultclearingtimeconsistsofthetimefortotalopeningofcircuitbreakerandthatforoperationofprotectiverelays(fromtheonsetoffaulttotheissuanceoftrippingpulse).10DL/T5147—20011Clearingtimeoflinefaults:incaseof500kVlines,0.08sfortheendproximatetofaults,0.1sfortheendfarawayfromfaults;incaseof2200.1sfortheendproximatetofaults,0.12sfortheendfarawayfromfaults.2Clearingtimeofbusbarfault:generally0.08～0.1s;fortheexistingbusbar,actualdataistaken.Iftheoperationtimeoftheexistinglineorbusbarrelayprotectiontakesexcessivetimegivingrisetostabilityproblemofthepowersystem,theoperationtimeofquick-actinglineorbusbarrelayprotectionshallbeusedforcalculation,coupledwithreplacingtheexistingrelayprotectiondevices.4ReclosingTimeforStabilityCalculationReclosingtimereferstothedurationfromfaultclearingtoreclosingofthemainbreaksofcircuitbreakersandshallbeselectedaccordingtosystemconditionsandsystemstabilityrequirements.1MinimumSingle-phaseReclosingTimeRestrictedbyArcSuppressionandInsulatorRecoveryTimeFollowingFaultClearinglThereclosingtimeshallbeselectedtobenolessthan0.5sfor:220kVlines;330kVand500kVlineswithalengthnomorethan150kmand100kmrespectively(withoutHVshuntreactorcompensation);all330kVand500kVlineswhosephase-to-phasecapacitanceiscompensatedbyHVshuntreactorswithsmallneutralreactors.2For330kVand500kVlinesthatarenotprovidedwithHVshuntreactorcompensationandhavealengthmorethan150kmand100kmrespectively,thereclosingtimeshallbeselectedwithreferencetotheactualsingle-phasereclosingtestresults.11DL/T5147—20012OptimalReclosingTimeForlinesvulnerabletostabilityproblem,theoptimalreclosingtimeshallbedeterminedbasedonthesystemstabilityconditionatthemomentwhenthecircuitbreakerisreclosedintheeventofpermanentfaults.Thatis,afterafaultoccurringtolinestransmittingthemaximumpoweriscleared,thereclosingshalloccuratthemomentwhenthephaseangleofunitsatsendingendrelativetothatofthesystematreceivingendswingsbacktotheproximityofthemaximumvaluewhereds/dtisnegativealongtheswingcurveafterpassingthemaximumvalue.5MathematicalModelandEquipmentParameters1SynchronousGeneratorModelConstanttransientpotentialmodelmaybeusedforsynchronousgeneratorsfarfromthefaultpoint.Variablesubtransientpotentialmodelshouldbeadoptedforsynchronousgeneratorsintheproximityofthefaultpointorthosewhosebehaviorsaretobespecificallystudied.EEdqDuringthestageofplanninganddesignorifcompleteEEdqparametersarenotavailable,constanttransientpotentialmodelmaybeused.2LoadModel

'or 'Themodelsandparametersshallbeappropriatelyselectedaccordingtotheactualloadcharacteristicsandtheprogramsused.lThemodelofsyntheticloadscanbecharacterizedbythestaticvoltage-frequencyexponentialfunctionwithappropriateexponentselected.Themodelofrelativelyconcentratedlarge-capacitymotorscanberepresentedbyanequivalentinductionmotorloadandastatic12DL/T5147—2001loadconnectedinparalleloncorresponding110kV(66kV)HVbusbar.Duringthestageofplanninganddesign,loadscanberepresentedbyconstantimpedance.3EquipmentParametersActualparametersareusedfortheexistingequipment;Designparametersareusedfornewlyaddedequipment.Duringthestageofplanninganddesignorifcompleteparametersarenotavailable,typicalparametersforequipmentofthesametypecanbeused.13DL/T5147—2001MainControlModeofSecurityandAutomaticityEquipment 1RapidReductionofOutputofPrimeMoversofThermalPowerUnitsRapidreductionofoutputofprimemoversofthermalpowerunits,alsocalledfastvalving,referstofastclosingtheturbinecontrolvalvetoreducetheoutputofsteamturbinewhenfaultsleadingtolossofstabilityoccurinthepowersystem.Dependinguponthetypesofsteamturbinesandtheircontrolsystems,thefastclosingoftheturbinecontrolvalvesinvolvesonlytheintermediatepressurecontrolvalveorboththeintermediatepressureandhighpressurecontrolvalves.thecontrolsystem,thecontrolvalvescanbeadjusted.Accordingtotherequirementsofpowersystemandadaptabilityofunits,fastvalvingisclassifiedintomomentaryfastvalvingandcontinuousfastvalving.1MomentaryFastMomentaryfastvalvingreferstoanactionthroughwhichsteamturbinecontrolvalvesareclosedinstantaneously(ontheorderofseveralseconds)andthenopenedtotheoriginalpositionsoastoreducetheturbinepowerrapidlyforashorttime.Thisisoneofthemeasurestobalancetheexcesskineticenergyofrotorsresultingfromdisturbancesinpowersystemandpreventlossofstabilityofthepowersystem.2ContinuousFastContinuousfastvalvingreferstoanactionthroughwhichsteam14DL/T5147—2001turbinecontrolvalvesareclosedinstantaneouslyandthenopenedtoanadjustedposition,coupledwithreducingtheboilerevaporationaccordingly,forthepurposeofreducingtheoutputpermanently.Itcanbeusedtoavoidlossofstabilityofpowersystem,restrictequipmentoverloadandfrequencyrise,andeliminateasynchronousoperation.2GeneratorSheddingGeneratortrippingcanpreventthepowersystemfromlossofstability,operation.Generally,generatortrippingisachievedbyopeningthecircuitbreakerofgenerator-transformerset.Thecontrolactionshallbeselectedbearinginmindthat:Trippinggeneratorsinhydropowerstationsisgivenpriorityoverthatinthermalpowerplants;inthermalpowerplants,trippinggeneratorsshouldonlybeappliedwhenfastvalvingisunavailableorinadequate.Theunitstobetrippedshallbeselectedsuchthatthetrippingofthemhastheminimuminfluenceontheauxiliarypower.3ElectricBrakingElectricbrakingreferstoswitchinginresistorswithapropercapacityonthebusbaratgeneratorendorathighvoltagesideforashorttimefollowingfaultclearingforthepurposeofabsorbingthefaultinducedaccelerationenergyofthegeneratorandslowingdownthegeneratorquicklyfollowingthefaultclearingsoastoimprovethestabilitylevel.Thereexistsanotherelectricbrakingmodeinwhicharesistorisconnectedattheneutralpointofatransformer.Inthiscase,currentcanflowthroughtheneutralpointduringgroundfault,allowingthe15DL/T5147—2001accelerationenergyofthegeneratorunittobeabsorbedpartially.Thiselectricbrakingmodeismostlyappliedinhydropowerstations,mainlyservingtopreventlossofstabilityofthepowersystem.4ConcentratedLoadSheddingConcentratedloadsheddingcanimprovethesystemoperatingfrequency,mitigateoverloadingofsomepowerlinesandimprovethereceiving-endvoltagelevel.Itisintendedtopreventlossofstability,eliminateasynchronousoperation,andlimitequipmentoverload.Topreventlossofstabilityofthepowersystem,concentratedloadscanbeswitchedoffbyuseofstabilitycontroldevices.Inthiscase,however,distributedloadsheddingshallbeappliedaswellinordertoimprovethereliabilityofcontrolsystemandthepowersupplyforkeyconsumers.5ControlRoleofShuntandSeriesCompensationDevicesForcedcompensationofseriescompensationdevicesandswitchingoffshuntreactorsorswitchinginshuntcapacitorsareintendedtopreventlossofstabilityandvoltagedrop.Incontrast,switchinginshuntreactorsorswitchingoffshuntcapacitorsismeanttolimitexcessivevoltage.6PowerSystemSplittingPowersystemsplittingreferstosplittingthepowersystemintoseveralpartswhichoperatesynchronouslywithbalancedactiveandreactivepower.Itcanpreventlossofstability,eliminateasynchronousoperationandlimitequipmentoverload.16DL/T5147—20017Auto-reclosingofTransmissionLinesAuto-reclosingoftransmissionlinesmainlypurportstorestoretheintegrityofpowergridtoenablecontinuouspowersupplyortodealwithsuccessivefaults.8ForcedExcitationofGeneratorsForceexcitationofgeneratorsisusedtoinstantaneouslyincreasethegeneratorexcitationvoltagetothepermissiblemaximumvaluewhenthegeneratorterminalvoltagedropsbelowthesettingsduetosystemfaultssoastoincreasethegeneratoroutletvoltageandpreventlossofstabilityofthepowersystem.9SwitchinginBackupPowerSourcesAutomaticstartupofreserveunitsinhydropowerstationsandpumpedstoragepowerstationsandautomaticswitchingofreservepowersourcesaccordingtothefrequencydropcanreducetheloadamounttobeswitchedoffandtherequiredtime.DCControlforAC/DCTransmissionSystemTheapplicationofDCcontrolforAC/DCtransmissionsystemcanpreventlossofstabilityoftheACsystemandlimittheequipmentoverload.Thespecificcontrolsinclude:emergentincreaseordecreaseofDCpower;adjustingACsystemfrequencyaccordingtothechangeintheDCtransmissionpower;adjustingreactivepowerthroughadjustingtheconvertercontrolangleorDCtransmissionpowertoallowforACvoltagecontrol.17DL/T5147—2001 AutomaticOutputIncreasingandDecreasingDeviceforHydropowerUnitsinCaseofPowerOut-of-StepSwingWhenhydropowerunitslosesynchronismwiththepowersystem,synchronismcanberestoredbyrapidlyincreasingordecreasingtheoutputofhydropowerunits.Ifthesystemfailstorestoresynchronismwithinaspecifiedtime,theout-of-stepsystemshallbedisconnected.18DL/T5147—2001ConfigurationandCompositionofSecurityandAutomaticityEquipment1ConfigurationandCompositionPrinciple1Theofequipmentshallbedeterminedbasedonthesafetyandstabilitycalculationandanalysisofthepowersystem.2Thesecurityandautomaticityequipmentshallbeconfiguredbasedontheprerequisitethatthereliabilityofsafetyandstabilitycontrolofthepowersystemisensured.Reliabilitymeansthatthedeviceoperateswheneveritisrequiredtooperate(dependency),andkeepsidleifnotrequiredtooperate(safety).Operationfailureofsecurityandautomaticityequipmentmaypossiblycausesomepowersystemaccidents,suchaslossofstabilityandfalseoperationofitmayleadtofalsepowerreductionandpartialloadloss.Boththecasesmayresultinsomeeconomiclossandshallbeweighedcarefullythroughmeticulousdesignandequipmentconfiguration.Thetyingbetweenthesecurityandautomaticityequipmentandrelayprotectiondeviceshallbereducedtotheminimum.3Theeffectivenessofpowersystemsafetyandstabilitycontrolshallbeguaranteed.First,thecontrolmeasuresforthesecurityandautomaticityequipmentandthecontrolledquantitiesshallbeselectedtomeettherequirements.Ifmultiplecontrolcommandsofthesamenaturebutatdifferentlevelsoccurconcurrentlywithinaspecified19DL/T5147—2001time,thecommandatthehighestlevelshallbeexecuted.Second,thecontrolledobjectswhicharemoreeffectiveforcontrollingthesafetyandstabilityofthepowersystemshallbeselected.Forexample,whenthecontrolledobjectsforrapidreductionofoutputinvolvemultipleunitsorpowerplants,theunit(s)orpowerplant(s)thataremosteffectiveintermsofcontroleffectshallbeselectedtocontrol.Third,thesecurityandautomaticitydeviceshouldoperaterapidlyandatappropriatetime.2AutomaticDevicesPreventingLossStabilityofPowerSystem1Whencalculatingthepowersystemstability,itshallbeensuredthatthepowersystemcanoperatestablyandthepowergridcansupplypowernormallyintheeventofIdisturbances.WhereaIIdisturbanceoccurspossiblyleadingtoloss