《电力系统继电保护及应用》课件-35KV及以下线路保护配置-双语

35KV以下线路保护配置微课WKE知识点：35KV及以下线路保护配置专业：电力类相关专业单元：线路保护Lineprotectionconfigurationfor35KVandbelowKnowledgepoint:Lineprotectionconfigurationfor35KVandbelowMajor:ElectricpowerrelatedmajorsUnit:LineProtection1.相间故障保护配置35kV和10kV系统相对简单，一般采用带方向或不带方向的电流电压保护作为相间故障的主保护及后备保护。主保护：瞬时电流速断保护和限时电流速断保护后备保护：定时限过电流保护Interphasefaultprotectionconfiguration35kVand10kVsystemsarerelativelysimple.Generally,directionalornon-directionalcurrentandvoltageprotectionisusedasthemainprotectionandbackupprotectionforinterphasefaults.Mainprotection:instantaneouscurrentquick-breakprotectionandtimelimitcurrentquick-breakprotectionBackupprotection:timelimitovercurrentprotection2.接地保护配置中性点不接地系统中线路的接地保护通常可以配置零序电压保护、零序电流保护、零序功率方向保护。零序电压保护又称为绝缘监视装置，根据系统发生单相接地故障时出现零序电压的特点实现，该装置只能判断发生故障的相别，不能判别故障线路，是无选择性接地保护。GroundprotectionconfigurationThegroundprotectionoflinesinsystemswithungroundedneutralpointscanusuallybeconfiguredwithzero-sequencevoltageprotection,zero-sequencecurrentprotection,andzero-sequencepowerdirectionprotection.Zero-sequencevoltageprotection,alsoknownasinsulationmonitoringdevice,isimplementedbasedonthecharacteristicsofzero-sequencevoltagewhenasingle-phasegroundfaultoccursinthesystem.Thedevicecanonlydeterminethephaseofthefault,butnotthefaultyline,andisanon-selectivegroundingprotection.2.接地保护配置在中性点不接地电网中发生单相接地短路时，故障线路的零序电流大于非故障线路的零序电流，利用这一特点可构成零序电流保护。在出线较少的中性点不直接接地电网中，发生单相接地故障时，故障线路的零序电流与非故障线路的零序电流相差不大，零序电流保护往往不能满足灵敏度的要求，需采用零序功率方向保护来地区分故障线路和非故障线路，从而有选择性地动作。GroundprotectionconfigurationWhenasingle-phasegroundingshortcircuitoccursinanungroundedpowergrid,thezero-sequencecurrentofthefaultlineisgreaterthanthezero-sequencecurrentofthenon-faultline.Thisfeaturecanbeusedtoformzero-sequencecurrentprotection.Inapowergridwithfewneutralpointsthatarenotdirectlygrounded,whenasingle-phasegroundfaultoccurs,thezero-sequencecurrentofthefaultlineisnotmuchdifferentfromthezero-sequencecurrentofthenon-faultline.Thezero-sequencecurrentprotectionoftencannotmeetthesensitivityrequirements.Zero-sequencepowerdirectionalprotectionneedstobeusedtodistinguishbetweenfaultylinesandnon-faultylines,soastooperateselectively.2.接地保护配置在中性点经消弧线圈接地的电网中，消弧线圈对基波电容电流有补偿作用，而消弧线圈的5次谐波电感电流相对于5次谐波电容电流来说是很小的，它起不了补偿5次谐波电容电流的作用，故在5次谐波分量中可以不考虑消弧线圈的影响。GroundprotectionconfigurationInapowergridwheretheneutralpointisgroundedthroughanarcsuppressioncoil,thearcsuppressioncoilhasacompensationeffectonthefundamentalcapacitancecurrent,andthe5thharmonicinductorcurrentofthearcsuppressioncoilisverysmallrelativetothe5thharmoniccapacitancecurrent,itcannotcompensateforthe5thharmoniccapacitorcurrent,sotheinfluenceofthearcsuppressioncoilcannotbeconsideredinthe5thharmoniccomponent.所以，需根据5次谐波零序电流的大小和方向来判别故障线路与非故障线路。2.接地保护配置这样，5次谐波电容电流在消弧线圈接地系统中的分配规律，就与基波在中性点不接地系统中的分配规律相同了。GroundprotectionconfigurationInthisway,thedistributionruleofthe5thharmoniccapacitivecurrentinthearcsuppressioncoilgroundedsystemisthesameasthedistributionruleofthefundamentalwaveintheneutralpointungroundedsystem.Therefore,itisnecessarytodistinguishfaultylinesfromnon-faultylinesbasedonthevalueanddirectionofthefifthharmoniczerosequencecurrent.2.接地保护配置目前，多数变电站综自系统中配置小电流接地选线装置，当小电流接地系统发生接地故障时，正确地选择出故障线路，为工作人员的检修提供方便。该装置的基本原理是将上述几种接地保护配合在一起，通过综合判断选择出故障线路。GroundprotectionconfigurationAtpresent,mostsubstationintegratedsystemsareequippedwithsmall-currentgroundinglineselectiondevices.Whenagroundfaultoccursinthesmall-currentgroundingsystem,thefaultylinecanbecorrectlyselectedtofacilitatemaintenancebystaff.Thebasicprincipleofthisdeviceistocombinetheabove-mentionedgroundingprotectionsandselectthefaultylinethroughcomprehensivejudgment.3.其他功能配置三相一次重合闸功能后加速保护过负荷保护低频减载功能01020304Three-phaseone-timereclosingfunctionPostaccelerationprotectionOverloadprotectionLowfrequencyloadsheddingfunctionInterphasefaultprotectionconfiguration3.其他功能配置三相一次重合闸功能后加速保护过负荷保护低频减载功能InterphasefaultprotectionconfigurationThree-phaseone-timereclosingfunctionPostaccelerationprotectionOverloadprotectionLowfrequencyloadsheddingfunction总结三段式定时限过流保护（可经低电压、方向闭锁），其中Ⅲ段可整定为反时限段（整定为反时限时，定时限过流Ⅱ、Ⅲ段保护自动退出）三段式定时限零序过流保护（可经方向闭锁），其中Ⅲ段可整定为反时限段（整定为反时限时，定时限零序过流Ⅱ、Ⅲ段保护自动退出）SummarizeThree-stagetimelimitovercurrentprotection(canbeblockedbylowvoltageanddirection),ofwhichstageIIIcanbesetasaninversetimelimit(whensettoinversetimelimit,thetimelimitovercurrentstageIIandstageIIIprotectionwillautomaticallyexit)Three-stagetimelimitzero-sequenceovercurrentprotection(canbeblockedbydirection),ofwhichstageIIIcanbesetasaninverse-timestage(whensettoinverse-time,thetimelimitzero-sequenceovercurrentstageIIandstageIIIprotectionwillautomaticallyexit)总结分散式小电流接地选线过负荷保护SummarizeDecentralizedlowcurrentgroundinglineselectionOverloadprotection合闸加速保护（前加速、后加速和手合后加速）Closingaccelerationprotection(frontacceleration,rearaccelerationandpost-closingacceleration)分散式低周减载（即按频率自动减负荷）保护Distributedlow-cycleloadshedding(i.e.automaticloadsheddingbasedonfrequency)protection总结低压解列功能三相一次重合闸(可实现检同期、检无压或非同期重合闸)SummarizeLowvoltagedelistingfunctionThree-phaseone-timereclosing(canrealizesynchronizat