文献翻译-配电网络 SCADA 系统中通用接地故障指示器的集成

IntegrationoftheUniversalEarth-faultIndicatorintotheDistributionNetworkSCADASystemDzintarsBaranovskis,Ph.Dstudent,M.Sc.Ing,RigaTechnicalUniversity;Developingdirector,LtdJUMIKS,andJanisRozenkronsAsoc.Professor,Dr.Sc.Ing.RigaTechnicalUniversity,LatviaAbstract-Thisworkdescribesthepossibilitiesfortheearthfaultdetectionatthecompensatedneutralnetworksandrepresentsonepracticalsolution-adevelopeduniversalearth-faultindicator(UEI),whichisallowedtodetecttheearth-faultsatthecompensatedneutralcablenetworksandthefaultdetectionwiththefaultindicators,whichisconnectedintodistributionnetworkSCADAsystembytheradiosignals.Theuniversalearth-faultindicatorisrealizedasadirectionalzero-sequenceprotectiondevicebasedoncomparisonofthetimewhenzero-sequencecurrentandzero-sequencevoltageoccurredwiththegiventime.Therearepresentedblock-diagramoftheuniversalearth-faultindicatorandworkingalgorithmse.t.c.Apilotproject“IntegrationofthefaultindicatorsintothedistributionnetworkSCADAsystem”hasreviewedwhichwascarriedoutatJelgavacabledistributionnetworksintheyear2003.IndexTermsElectronicequipment,Faultlocation,Powersystemreliability,Powerquality,SCADAsystemI.INTRODUCTION.Inpractice,intheexistingcableandoverheaddistributionnetworksearthfaultsandshort-circuitsfrequentlyoccur.Thereforeforpowerengineeringcompaniesitisveryim-portanttofindafaultedplacefasterandattheleastexpense.Thepossibilitytodetectfaultsaredependwhatkindofneutralworkregimeareused.Low-ohmicearthed,compensatedandisolatedneutralworkingregimesareusedinLatviancablenetworks.Somecompanies(forexample,theLatvianpowerengineeringcompany“Latvenergo”)fordetectionofafaultedlinehaveusedthecablefaultindicators(FIs)intheoutgoinglinesfordetectionoffaultsatthetransformerstationlevel.NorwegianandGermanfaultindicatorsCabletroll,EKL1andEKA3areappliedinthe“Latvenergo”mediumvoltagecablenetworksforthedetectionofearth-faults.TheseFIsareoflimitedapplication,becauseitisimpossibletousethemincablenetworkswithcompensatedneutralforthedetectionofearth-faultsandthenumberofthefaultindicatorsisnotenoughyet.AtthenetworkplaceswhereyetarenotmountedFIsandatthecompensatedneutralnetworksareusedportablehigh-harmonicmeasuringinstruments-3and-3Mforthedetectionofearth-faults.Forthesedevicesarelimitedapplicationbecauseitspossibletouseonlyincaseiffaultedlineisundervoltage,butthisregimeisdangerousbecausefaultcanrisefromone-phaseearthfaulttotwo-phaseearthfaultorshort-circuit.Forimprovingthefaultdetectionandmakingitfasterauniversalearth-faultindicator(UEI)hasbeendeveloped,whichallowstodetecttheearth-faultsinthecompensatedcablenetworks.InEurope,therearenoearth-faultindicatorsofthiskind.II.POSSIBILITIESTODETECTTHEEARTHFAULTS.Themethodfortheearthfaultdetectionisdependedonnetworksneutralworkregime.Forexample,inpracticetheearthfaultsarepossibletodetectintwoways:a)ByusingfaultindicatorsandintegrateditsintothedistributionnetworkSCADAsystem.Inthiscasethefaultisdetectediffaultedlineisundervoltageorfaultedlineisswitchedoffautomatically;b)Byusingtheportablehigh-harmonicmeasuringinstruments.Inthiscaseitistimeconsumingprocessandfaultisdetectedonlyiffaultedlineisundervoltage.Themethodswhatcouldbeusedinfaultindicatorsorinportablemeasuringinstrumentsforthedetectionoftheearthfaultsdependsonneutralworkingregimeareshownintable1.TABLE1.THEMETHODSWHATCOULDBEUSEDFORTHEDETECTIONOFTHEEARTHFAULTSDEPENDSONNEUTRALWORKINGREGIMESMethodIsolatedneutralnetworkCompensatedneutralnetworkLow-ohmicearthedneutralnetworkCompensatedneutralwithadditionalresistornetworkComparisonofthezero-sequencecurrentsonfaultedandnonfaultedlines+Usingoftheearthfaulttransients+Usingofthenaturalhighharmonics+1+1,+1Using25Hzor100Hzhighharmonics+Directionalzero-sequenceprotection+2+1Thismethodcanbeusedonlyforportablemeasuringinstruments,whenfaultedlineisundervoltage.2Notusedinpractisebecausenoteconomical.Therearedifferentexpensesforproducingofthefaultindicatorsandmeasuringinstrumentsandspecificearthfaultdetectiondependsontheusedmethod.Afterevaluationoftheallabovementionedmethodsmoreefficientandeconomicallyprofitablemethodforproducingoftheuniversalearth-faultindicator(UEI)isdirectionalzero-sequenceprotection,because:Forprotectionswhatareworkingontheearthfaulttransientsthemainimperfectionthatitsarenotsensitiveforsteadycurrentsofthefaults,thereforeisnotpossibletodosecondautoreclosing.Inadditionitisdifficulttocalculatethecurrentsandresistanceofthetransientswhatsdependedonmomentwhenfaultisoccur.Forapparatuswhichareworkingfromthenaturalhighharmonicsthemainimperfectionthatoftensumofthehighharmonicischangeableatthemomentofthefault,thereforethismethodisnotusableforstationaryequipments(faultindicatorsorrelays).Forprotectionwhichisworkingfromthecurrentofthe25Hzor100Hzhighharmonicsisneedextrapowersupplyunitforgenerationofthehighharmonicsandinadditionisneedthespecialfiltersforrelayswhatismountedatthesubstations.Notusedinpracticebecausenoteconomical.Thismethodisnoteconomicalyprofitable.III.THEUNIVERSALEARTH-FAULTINDICATORTheuniversalearth-faultindicatorisrealizedasadirectionalzero-sequenceprotectiondevicebasedoncomparisonofthetimewhenzero-sequencecurrentandzero-sequencevoltageoccurredwiththegiventime.Asthezero-sequencecurrent3I0elementsareusedthezero-sequencecurrenttransformers(“feranti”)orzero-sequencecurrentsensorswhichismountedatthetransformerstationsandasthezero-sequencevoltage3U0elementsvoltagetransformerswhichismountedatthesubstation(oneforallUEI).Theindicatorismeasuringthezero-sequencecurrentsandzero-sequencevoltageandanglebetweenthem.Theuniversalearth-faultindicatorisfixedfaultif(seefigure1):azero-sequencecurrent3I0ishigherthansettingvalue10mA;azero-sequencevoltage3U0ishigherthansettingvalue20V;aphaseanglebetween3I0and3U0isinworkingzone21,whereangleoftheworkingzone;1;2bordersoftheworkingzone.Fig.1.Workingdiagramoftheindicator.Itispossibletoseetheindicatorsworkingandnotworkingzonesatthefigure1.Innormallineconditioniflineisnotfaulted,thezero-sequencecurrent3I0isnotintheworkingzone,butincaseoftheearthfault-zero-sequencecurrentdecreaseandchangeangleregardingthe3U0andturnintheindicatorsworkingzoneandearthfaultisfixed.Inpractisetheindicatorisadjustedasitsworkingzoneisbetween80oand+80o,or80o+80oTheexchangesofthezero-sequencecurrent3I0andzero-sequencevoltage3U0atthethreecriticalsituationsareshowninfigures2,3and4.Theindicatorisadjustedsothatitasprimaryconstantlymeasurethe3U0andafter-3I0andafterthatdependsonanglebetweenisfixedthefault.Disagree=(1)wheredisagree-disagreeangle.Thetimewhatagreetoangledisagree,isthefollowing:(2)whereTtimeoftheperiod(20ms).Inpracticetheindicatorisadjustedsothatitworkeddependsonthemeasuredtimerangeanditsworkingzoneisthefollowing:04mstmeasand16tmeas20mswheretmeasmeasuredtimeoftheindicatorfrommomentwhenzero-sequencevoltage3U0isequal0tillmomentwhenzero-sequencecurrent3I0isequal0.Indicatornotworkingzoneisthefollowing:4mstmeas16ms.1)Thebesteventwhenindicatorisworkingperfectlyandtdisagree=tmeas=0Fig.2.2)Criticaleventwhen=800and3I0getahead3U0.tmeas=2tdisagreeFig.3.3)Criticaleventwhen=+800and3I0dropback3U0.tmeans=tdisagreeFig.4.Ablock-diagramoftheuniversalearth-faultindicatorisshowninFig.5.Attransformerstationsofthemediumvoltagecablenetworksaseparateunit(A)ismounted,in-cludinganin-seriesconnectedsensor(1)ofzerosequencecurrent,afilter(2)ofthefirstharmonicandacomparator(4)beingconnectedtoanexecutiveunit(5)coupledtoatransmitter(13)which,viaatelecommunicationchannel,transmitssignalstoareceiver(14).Areceiver(11)ofzero-sequencevoltageisconnectedtotheotheroutputofthecomparator(4),whileatthesub-stationaunit(B)isinstalled,comprisinganin-seriesconnectedzero-sequencevoltagesensor(6),afilter(7)ofthefirstharmonicandavoltagecomparator(8)connectedtoatransmitter(9)ofzero-sequencevoltage,which,viaatelecommunicationchannel(10),transmitsmeasurementsofzero-sequencevoltagetothereceiver(11).Atthedispatchercenteraunit(C)isinstalled,consistingofthein-seriesconnectedreceiver(14)andacomputerwithsoftware(15).Fig.5.Block-diagramoftheuniversalearth-faultindicator.IV.INTEGRATIONOFTHEFAULTINDICATORSINTOTHEDISTRIBUTIONNETWORKSCADASYSTEM.Fortheimprovingthefaultdetectionandmakingitfaster,apilotproject“IntegrationofthefaultindicatorsintothedistributionnetworkSCADAsystem”wasworkedoutforthe“Latvenergo”distributionnetworks.Toconnect49faultindicators(forexample,“Nortroll”companys“Cabletroll2700”faultindicators)intotheSCADAsystem,havedevelopedadatatransmissionandregistrationsystemfortheseindicators.ThissystemwasrealizedattheJelgavacableandoverheadnetworksin2002-2003.Themainideaofthisprojectis:inthecaseoffaultstotransmittheinformationfromindicatorstothedispatchercenterimmediately.Thesystemconsistsofthefollowingcomponents(seeFig.6):aradiotransmitterwithacontroller.Itsaremountedatthetransformerstationandconnectedwithfaultindicators.Thetransmittermustreceivesignalsfromtheindicatorsandtransfertheinformationtotheradioreceiver;aradioreceiverwithacontroller.Itsaremountedatthedispatchercenter(oneforalldistributionnetworksubsidiaries).Thereceivermustreceivesignalsfromthetransmitterandtransfertheinformationtothedispatcherscomputer;acomputerprogrammustbeinstalledinthedispatcherscomputer.Thiswouldallowforlocationofaflashingindicatorandofthefaultyplace.Thesystemisworkingatthe146,1125MHzradiofrequency.Inthecaseoffaultthedispatcherdetectsimmediatelythefaultedlinefromtheprogramsschemesanddatabase.Fig.6.Structureofthesystemforafaultindicatorsdatatransmissionandregistration(FIfaultindicator)Thesystemhasbeenworkingforapproximatelytwoyearswithoutanydefects.V.CONCLUSIONANDFUTUREWORK.Morereliable,effectiveandeconomicallyjustifiedmethodfortheearthfaultdetectionatthecompensatedneutralnetworksistousetheuniversalearth-faultindicator(UEI)whichisconnectedintodistributionnetworkSCADAsystembytheradiosignals.Itswillgivethefollowingadvantages:itiswillbepossibletodetecttheearthfaultsatthecompensatedneutralcablenetworks;thenetworksstaymorereliableandwithlessdisturbances;thetimeforthefaultdetectionis23timessmallerthanbefore;lessexpensesarerequiredforthefaultdetection,becausethereisnoneedanymoreforpowerengineeringcompaniesstafftodrivetoeachsubstation;incaseofthefaultsdispatcherscanreceivetheinformationfromtheindicatorsautomatically.Oneofthebestwayshowtodetecttheearthfaultscouldbeanequipmentwhatautomaticallycouldmeasuredthetodistancefromsubstationtoearthfaultplace,butitisnotpossibletofindaccurate,reliableandsimplemathematicalalgorithmforallkindofearthfaultwhatcanbeusedinequipment.Itisworkforfuture.VI.REFERENCESBooks:1A.“”.:,1991,pp.496.2.B.“”.,.:1971,pp.624.3.M.“-.”,.:,1984,pp.520.4RomanH.,PietzschH.“Earth-faulttreatmentinMV-networks”,CIREDIEEConf.Publication,1997,pp.4384.36.5KugiA.,DrumlG.“Anewmethodforthelocationoflow-andhigh-resistanceearthfault”,FaultlocationandanalysisPSP98Bled/Slovenia6570.6LakerviE.,MkinenA.,NikanderA.,HaaseH.“Effectsandreductionofshortinterruptionsinruralelectricitydistributionsystems”,PQA94ThirdIntern.Conf.onPowerQuality;End-UseApplicationsandPerspectivesAmsterdam(TheNetherlands),Oct1994.7LehtonenM.“Transientanalysisforgroundfaultdistanceestimationinelectricaldistributionnetworks”,ESPOOTechnicalResearchCentreofFinland,Publications115,181.,1992.8WimterK.“Theearthfaultproblemandthetreatmentoftheneutralindistributionnetworks”,ERA2:1418(inSwedish).,1987.9.,.,.“”,.:.,1974.PapersfromConferenceProceedings(Published)10BaranovskisDz.,RozenkronsJ.,“Developmentoftheearth-faultindicatorsandintegrationintotheSCADAsystemofdistributionnetworks”,EPE-PEMC2004,Riga.11BaranovskisDz.,RozenkronsJ.,“Integrationoftheearth-faultindicatorsintothedistributionnetworkSCADAsystem”,4thInternationalConferenceElectricPowerQualityandSupplyReliability,2004,Estonia.Patents:12BaranovskisDz.,OsipovsS.,RozenkronsJ.,“Indicatorofearthshortcircuitlocationinsingle-phasepowerlines”,Latvia,Patent13026,09.september2003.VII.BIOGRAPHIESDzintarsBaranovskiswasborninDobeleintheLatvia,onOctober20,1974.HeisthirdyearPh.DstudentinRigaTechnicalUniversityinPowerandElectricalengineeringfaculty.HegraduatedM.sc.ing.fromtheRigaTechnicalUniversityandMasterofthebusinessadministrationfromRigaInternationalSchoolofEconomicsandBusinessAdministration.HisemploymentexperienceincludedtheLatvianpowersystemLatvenergo”,telecomunicationcompanyCLS”andnow-ElectricalengineeringcompanyJUMIKS”,whereheisdevelopingdirector.Areaofresearchactivity:NeutralEarthingandEarth-faultprotectionandearth-faultdetectioninamediumvoltagenetworks.5scientificpublicationsand1patent.Hehasseveralawardsandgrantsforstudentscientificworks.JanisRozenkronswasborninLatvia(LR)onJune25,1939.HegraduatedfromtheRigaPolytehnicalInstitute.HeisProfessorofRiga.TechnicalUniversity(RTU),Dr.sc.ing.HisemploymentexperienceincludestheLatvianpowersystemLatvenergo”andRTU.Areaofresearchactivity:NeutralEarthingandEarth-faultprotectioninamediumvoltagenetworks.Morethan100scientificpublicationsand20patents.TwosilvermedalsinformerUSSReffortexhibition,Moscow.PrincipalinvestigatoroftheLatvianScientificCouncilgrant05.1683.ProjectmanageroftheEuropeanCommissionprojectEurowin”fromLatvianpart(1994-1996)andmorethan20contractswithLatvenergoregardingmediumvoltagenetworkneutralearthing.AwardedwithYearpriceofLatvianAcademyofScienceandLatvenergoinpowerengineering(2004).Integrationoftheuniversalearth-faultindicatorintothedistributionnetworkSCADAsystemBaranovskis,D.;Rozenkrons,J.PowerTech,2005IEEERussiaDOI:10.1109/PTC.2005.4524837PublicationYear:2005,Page(s):1-5Citedby:Papers(2)IEEECONFERENCEPUBLICATIONS配电网络SCADA系统中通用接地故障指示器的集成DzintarsBaranovskis,Ph.Dstudent,M.Sc.Ing,RigaTechnicalUniversity;Developingdirector,LtdJUMIKS,andJanisRozenkronsAsoc.Professor,Dr.Sc.Ing.RigaTechnicalUniversity,LatviaIntegrationoftheUniversalEarth-faultIndicatorintotheDistributionNetworkSCADASystemDzintarsBaranovskis,Ph.Dstudent,M.Sc.Ing,RigaTechnicalUniversity;Developingdirector,LtdJUMIKS,andJanisRozenkronsAsoc.Professor,Dr.Sc.Ing.RigaTechnicalUniversity,LatviaAbstract-Thisworkdescribesthepossibilitiesfortheearthfaultdetectionatthecompensatedneutralnetworksandrepresentsonepracticalsolution-adevelopeduniversalearth-faultindicator(UEI),whichisallowedtodetecttheearth-faultsatthecompensatedneutralcablenetworksandthefaultdetectionwiththefaultindicators,whichisconnectedintodistributionnetworkSCADAsystembytheradiosignals.Theuniversalearth-faultindicatorisrealizedasadirectionalzero-sequenceprotectiondevicebasedoncomparisonofthetimewhenzero-sequencecurrentandzero-sequencevoltageoccurredwiththegiventime.Therearepresentedblock-diagramoftheuniversalearth-faultindicatorandworkingalgorithmse.t.c.Apilotproject“IntegrationofthefaultindicatorsintothedistributionnetworkSCADAsystem”hasreviewedwhichwascarriedoutatJelgavacabledistributionnetworksintheyear2003.IndexTermsElectronicequipment,Faultlocation,Powersystemreliability,Powerquality,SCADAsystem摘要这项研究描述了补偿配电网络在接地故障检测的可能性，并提出一个实用的解决方案发达国家通用接地故障指示器（UEI），它可以将补偿中性电缆网络检测到的接地故障，故障检测与故障指示器，由无线电信号连接到配电网SCADA系统的。通用的接地故障指示器是作为零序方向保护装置，它是基于零序电流和零序电压发生时间与给定时间的比较来实现的。这里给出了通用接地故障指示器和工作算法的框图。2003年在叶尔加瓦（Jelgava）电缆配电网络对故障指示器融入配电网SCADA系统的试点项目进行了审查。关键词电子设备、故障定位、电力系统可靠性、电能质量、SCADA系统一、介绍在实际中，现有电缆和架空配电网络的接地故障和短路频繁地发生。因此更快最省钱地找出出现故障的地方，对电力工程公司是非常重要。探测故障很大程度上是取决于中性点接地的类型。低电阻接地、补偿和隔离的中性电接地方式被用在拉脱维亚（Latvian）的电缆网络。一些公司（例如，拉脱维亚（Latvian）电力工程公司Latvenergo）的断线检测已用于电缆故障指示器(FIs)在传出线站一级变压器故障检测中。挪威和德国的故障指示器：Cabletroll、EKL1和EKA3已应用在Latvenergo中压电缆网络的接地故障检测中。这些电缆故障指示器FIs的应用范围是有限的，因为它们不可能使用在电缆网络与补偿中性接地故障的检测中，而且故障指标的数目仍未足够。在电网还没有安装FIs和补偿的地方，依旧是用便携式高谐波测量仪器-3和-3M的接地故障检测方式。这些设备的应用范围是有限，因为它只能使用在欠压引起断路的情况下，但这种方式存在危险性，因为故障可以从单相接地故障上升到两相接地故障或短路。改进的故障检测，使通用接地故障指示器（UEI）得到了更快地发展，它允许补偿的电缆网络中检测接地故障。在欧洲，没有这样的接地故障指示器。二、检测接地故障的可能性接地故障检测的方法取决于电网的中性点接地方式。例如，在现实中接地故障可以用两种方式来检测：a)使用故障指示器和集成的配电网络SCADA系统。在这种情况下可以检测出故障是由于欠电压还是因切断电源故障引起的。b）通过使用便携式的高谐波测量仪器。在这种情况下故障检测只有当短路是由于欠电压引起的才能检测到，并且耗时长。表1所示中性点接地方式决定用故障指示器还是便携式测量仪器来检测接地故障。表1可以用于接地故障检测的方法取决于中性点接地方式1此方法仅用于便携式测量仪器，此时故障线路是欠压。2此方法不用在实际中，因为不经济。不同费用的产生是由于故障指示灯、测量仪器和具体的接地故障检测所用的方法的不同。比上面提及的方法更有效和经济收益普遍的接地故障的生产方法评价指标(UEI)，它是所有的定向的零序保护，原因有：保护工作在有接地故障时的缺点是稳恒电流不敏感，因此不会再次出现自动重合闸。此外，很难计算故障出现瞬间电流和电阻的值。装置在有高次谐波时的主要缺陷是发生故障时的高次谐波总和经常多变，因此这种方法不是用于固定设备（故障指示器或继电器）。目前25Hz或100Hz的高次谐波的保护是需要额外的电源装置，此外是需要为在变电站的继电器安装特殊滤波器。因为不经济所以在实际中此方法应用很少。三、通用接地故障指示器作为一种基于零序电流和零序电压在发生与给定的时间的时间比较的零序方向保护装置，实现了通用的接地故障指示器。作为零序电流3I0的零序电流互感器（feranti）或零序电流传感器被安装在变压器上以及零序电压3U0电压变压器安装在变电站（一个用于所有符合UEI）。该指标衡量零序电流和零序电压和它们之间的角度。如果通用接地故障指示器确定故障（见图1）：零序电流3I0大于设定值10mA；零序电压3U0是高于设定值20V；相角在3I0和3U0之间，12，工作区域；1；2；工作区域的边界。图1.指示器工作示意图在图1可以看到指标的工作区和非工作区。在线路正常的情况如果未出现故障，零序电流3I0不是在工作区中，但在有接地故障时，零序电流减小和3U0的角度改变，上述的指示器工作区和接地故障之间的角发生偏转。在实际中，其指标是在工作区80和+80之间调整或80+80。零序电流3I0和零序电压3U0在三种临界情况如图2、3和4所示。故障指示器作为首要的不断测量3U0和-3I0之后，这取决于角度之间固定故障调整指标。（1）disagreisr表示disagreeangle.当满足disagre时，有：（2）2disagretTT表示时间周期。在实际中，指标不断进行调整，它取决于测量的时间范围和其工作区如下：和ms4t0easms20t16easTmeas表示指示器测量时间：从零序电压3U0时等于0，零序电流3I0等于0的时刻。指示器非工作区如下：s16ts4meas1）指示器理想工作状态：0tteasdisagr图22)=80o，3I0超前3U0的临界状态：disagremeast2t图33)=+80o，3I0滞后3U0的临界状态：disagremeat图4通用接地故障指示器框图如图5所示。在变电站中压电缆网络安装(A)是一个独立的单位，包括一系列连接的零序电流传感器（1）、一次谐波滤波器（2）的和比较器（4），被连接到执行在网站的单元（5）耦合到变送器（13），通过一个通信通道传送信号到一个接收器（14）。接收机（11）的零序电压连接到其他输出的比较器（4），而子站单元(B)的安装，包括串联连接的零序电压传感器（6）一次谐波滤波器（7）和电压比较器（8）连接到发射机（9）的零序电压，通过电信通道（10）传送到接收机（11）的零序电压的测量。在调度中心安装装置（C）组成的系列中连接接收机（14）和一台电脑与软件(15)。图5.通用的接地故障指示器的框图四、故障指示器并入配电网SCADA系统为了改进故障检测使它更快，一个名为故障指示器融入配电网SCADA系统的试点项目就是为Latvenergo分布网络成立的。要连接49个故障指示器（例如，Nortroll公司的Cabletroll2700故障指示器）到SCADA系统中，已经制定了这些指标的数据传输和注册制度。2002-2003年，在叶尔加瓦电缆和架空网络实现