35KV以下線(xiàn)路保護(hù)配置微課WKE知識(shí)點(diǎn)：35KV及以下線(xiàn)路保護(hù)配置專(zhuān)業(yè)：電力類(lèi)相關(guān)專(zhuān)業(yè)單元：線(xiàn)路保護(hù)Lineprotectionconfigurationfor35KVandbelowKnowledgepoint:Lineprotectionconfigurationfor35KVandbelowMajor:ElectricpowerrelatedmajorsUnit:LineProtection1.相間故障保護(hù)配置35kV和10kV系統(tǒng)相對(duì)簡(jiǎn)單，一般采用帶方向或不帶方向的電流電壓保護(hù)作為相間故障的主保護(hù)及后備保護(hù)。主保護(hù)：瞬時(shí)電流速斷保護(hù)和限時(shí)電流速斷保護(hù)后備保護(hù)：定時(shí)限過(guò)電流保護(hù)Interphasefaultprotectionconfiguration35kVand10kVsystemsarerelativelysimple.Generally,directionalornon-directionalcurrentandvoltageprotectionisusedasthemainprotectionandbackupprotectionforinterphasefaults.Mainprotection:instantaneouscurrentquick-breakprotectionandtimelimitcurrentquick-breakprotectionBackupprotection:timelimitovercurrentprotection2.接地保護(hù)配置中性點(diǎn)不接地系統(tǒng)中線(xiàn)路的接地保護(hù)通常可以配置零序電壓保護(hù)、零序電流保護(hù)、零序功率方向保護(hù)。零序電壓保護(hù)又稱(chēng)為絕緣監(jiān)視裝置，根據(jù)系統(tǒng)發(fā)生單相接地故障時(shí)出現(xiàn)零序電壓的特點(diǎn)實(shí)現(xiàn)，該裝置只能判斷發(fā)生故障的相別，不能判別故障線(xiàn)路，是無(wú)選擇性接地保護(hù)。GroundprotectionconfigurationThegroundprotectionoflinesinsystemswithungroundedneutralpointscanusuallybeconfiguredwithzero-sequencevoltageprotection,zero-sequencecurrentprotection,andzero-sequencepowerdirectionprotection.Zero-sequencevoltageprotection,alsoknownasinsulationmonitoringdevice,isimplementedbasedonthecharacteristicsofzero-sequencevoltagewhenasingle-phasegroundfaultoccursinthesystem.Thedevicecanonlydeterminethephaseofthefault,butnotthefaultyline,andisanon-selectivegroundingprotection.2.接地保護(hù)配置在中性點(diǎn)不接地電網(wǎng)中發(fā)生單相接地短路時(shí)，故障線(xiàn)路的零序電流大于非故障線(xiàn)路的零序電流，利用這一特點(diǎn)可構(gòu)成零序電流保護(hù)。在出線(xiàn)較少的中性點(diǎn)不直接接地電網(wǎng)中，發(fā)生單相接地故障時(shí)，故障線(xiàn)路的零序電流與非故障線(xiàn)路的零序電流相差不大，零序電流保護(hù)往往不能滿(mǎn)足靈敏度的要求，需采用零序功率方向保護(hù)來(lái)地區(qū)分故障線(xiàn)路和非故障線(xiàn)路，從而有選擇性地動(dòng)作。GroundprotectionconfigurationWhenasingle-phasegroundingshortcircuitoccursinanungroundedpowergrid,thezero-sequencecurrentofthefaultlineisgreaterthanthezero-sequencecurrentofthenon-faultline.Thisfeaturecanbeusedtoformzero-sequencecurrentprotection.Inapowergridwithfewneutralpointsthatarenotdirectlygrounded,whenasingle-phasegroundfaultoccurs,thezero-sequencecurrentofthefaultlineisnotmuchdifferentfromthezero-sequencecurrentofthenon-faultline.Thezero-sequencecurrentprotectionoftencannotmeetthesensitivityrequirements.Zero-sequencepowerdirectionalprotectionneedstobeusedtodistinguishbetweenfaultylinesandnon-faultylines,soastooperateselectively.2.接地保護(hù)配置在中性點(diǎn)經(jīng)消弧線(xiàn)圈接地的電網(wǎng)中，消弧線(xiàn)圈對(duì)基波電容電流有補(bǔ)償作用，而消弧線(xiàn)圈的5次諧波電感電流相對(duì)于5次諧波電容電流來(lái)說(shuō)是很小的，它起不了補(bǔ)償5次諧波電容電流的作用，故在5次諧波分量中可以不考慮消弧線(xiàn)圈的影響。GroundprotectionconfigurationInapowergridwheretheneutralpointisgroundedthroughanarcsuppressioncoil,thearcsuppressioncoilhasacompensationeffectonthefundamentalcapacitancecurrent,andthe5thharmonicinductorcurrentofthearcsuppressioncoilisverysmallrelativetothe5thharmoniccapacitancecurrent,itcannotcompensateforthe5thharmoniccapacitorcurrent,sotheinfluenceofthearcsuppressioncoilcannotbeconsideredinthe5thharmoniccomponent.所以，需根據(jù)5次諧波零序電流的大小和方向來(lái)判別故障線(xiàn)路與非故障線(xiàn)路。2.接地保護(hù)配置這樣，5次諧波電容電流在消弧線(xiàn)圈接地系統(tǒng)中的分配規(guī)律，就與基波在中性點(diǎn)不接地系統(tǒng)中的分配規(guī)律相同了。GroundprotectionconfigurationInthisway,thedistributionruleofthe5thharmoniccapacitivecurrentinthearcsuppressioncoilgroundedsystemisthesameasthedistributionruleofthefundamentalwaveintheneutralpointungroundedsystem.Therefore,itisnecessarytodistinguishfaultylinesfromnon-faultylinesbasedonthevalueanddirectionofthefifthharmoniczerosequencecurrent.2.接地保護(hù)配置目前，多數(shù)變電站綜自系統(tǒng)中配置小電流接地選線(xiàn)裝置，當(dāng)小電流接地系統(tǒng)發(fā)生接地故障時(shí)，正確地選擇出故障線(xiàn)路，為工作人員的檢修提供方便。該裝置的基本原理是將上述幾種接地保護(hù)配合在一起，通過(guò)綜合判斷選擇出故障線(xiàn)路。GroundprotectionconfigurationAtpresent,mostsubstationintegratedsystemsareequippedwithsmall-currentgroundinglineselectiondevices.Whenagroundfaultoccursinthesmall-currentgroundingsystem,thefaultylinecanbecorrectlyselectedtofacilitatemaintenancebystaff.Thebasicprincipleofthisdeviceistocombinetheabove-mentionedgroundingprotectionsandselectthefaultylinethroughcomprehensivejudgment.3.其他功能配置三相一次重合閘功能后加速保護(hù)過(guò)負(fù)荷保護(hù)低頻減載功能01020304Three-phaseone-timereclosingfunctionPostaccelerationprotectionOverloadprotectionLowfrequencyloadsheddingfunctionInterphasefaultprotectionconfiguration3.其他功能配置三相一次重合閘功能后加速保護(hù)過(guò)負(fù)荷保護(hù)低頻減載功能InterphasefaultprotectionconfigurationThree-phaseone-timereclosingfunctionPostaccelerationprotectionOverloadprotectionLowfrequencyloadsheddingfunction總結(jié)三段式定時(shí)限過(guò)流保護(hù)（可經(jīng)低電壓、方向閉鎖），其中Ⅲ段可整定為反時(shí)限段（整定為反時(shí)限時(shí)，定時(shí)限過(guò)流Ⅱ、Ⅲ段保護(hù)自動(dòng)退出）三段式定時(shí)限零序過(guò)流保護(hù)（可經(jīng)方向閉鎖），其中Ⅲ段可整定為反時(shí)限段（整定為反時(shí)限時(shí)，定時(shí)限零序過(guò)流Ⅱ、Ⅲ段保護(hù)自動(dòng)退出）SummarizeThree-stagetimelimitovercurrentprotection(canbeblockedbylowvoltageanddirection),ofwhichstageIIIcanbesetasaninversetimelimit(whensettoinversetimelimit,thetimelimitovercurrentstageIIandstageIIIprotectionwillautomaticallyexit)Three-stagetimelimitzero-sequenceovercurrentprotection(canbeblockedbydirection),ofwhichstageIIIcanbesetasaninverse-timestage(whensettoinverse-time,thetimelimitzero-sequenceovercurrentstageIIandstageIIIprotectionwillautomaticallyexit)總結(jié)分散式小電流接地選線(xiàn)過(guò)負(fù)荷保護(hù)SummarizeDecentralizedlowcurrentgroundinglineselectionOverloadprotection合閘加速保護(hù)（前加速、后加速和手合后加速）Closingaccelerationprotection(frontacceleration,rearaccelerationandpost-closingacceleration)分散式低周減載（即按頻率自動(dòng)減負(fù)荷）保護(hù)Distributedlow-cycleloadshedding(i.e.automaticloadsheddingbasedonfrequency)protection總結(jié)低壓解列功能三相一次重合閘(可實(shí)現(xiàn)檢同期、檢無(wú)壓或非同期重合閘)SummarizeLowvoltagedelistingfunctionThree-phaseone-timereclosing(canrealizesynchronizat