输电线路高阻接地故障检测的新方法研究

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1、上海交通大学硕士学位论文输电线路高阻接地故障检测的新方法研究姓名：陈佳佳申请学位级别：硕士专业：电力系统及其自动化指导教师：邰能灵20070101上海交通大学硕士学位论文摘要量和与基波能量之比形成区分故障与正常投切的判据。大量ATP仿真以及RDTS实验结果表明，该方法具有良好的性能，能准确识别高阻接地故障，并能保证在系统正常投切时不误发信号，从而提高电网行安全性和可靠性。最后，综合全文分析，对整个研究工作存在的问题和有待于解决的问题进行了总结。关键词：高阻接地，小波变换，模极大值，并联电容器，空载合闸，

2、单相重合闸，谐波分量，暂态，能量上海交通大学硕士学位论文ABSTRACTANOVELTECHNIQUEFORSINGLEPHASEHIGH-IMPEDANCEFAULTDETECTIONABSTRACTGenerally,thetransmissionlinefaultcancausehighphasecurrent.Propergroundingprotectionsetcantripreliablyandcutoffthefault.However,someuniquegeographicalcha

3、racters,suchasfiregrounding,bamboogroundingandtreetopgrounding,cancausesinglephasehigh-impedancegroundingfaultfrequently,whichcauselowlevelcurrentinpractice.Especiallyinthecaseofthehigh-voltagetransmissionlines,highimpedancefaults(HIF)arecharacterizedbya

4、nintermittentArc-typenatureandlowlevelofthefaultcurrents.Thedetectionofthelow-levelgroundcurrentswiththeconventionalover-currentrelaysisdifficultandsometimesinaccurate.Toanalysisthefaultcomponent,wavelettransformcanbeseenasawell-developedmathematicaltool

5、.Itcanbeformulatedtodescribesignalsinalocalizedtimeandfrequencyformat.Analysisresultsshowthatwhenasinglephasefaulthappensinthetransmissionline,wavelettransformmodulusmaximaofthezero-sequencecurrentandthefaultphasecurrentwillpresentspecialcharacteristics.

6、AnewschemebasedonthecharacteristicsispresentedtodetecttheHIF.Furthermore,thechangesofcurrentandvoltagecausedbythenormal上海交通大学硕士学位论文ABSTRACTswitchingeventssuchasswitchingontheshuntcapacitorsmaybeidentifiedasthefaultandinducemaloperation.Inordertoenhanceth

7、ereliabilityofHIFdetection,todistinguishHIFfromthenormalswitchingeventsisapivotalproblem.Analysisresultsshowthatthedistortedcurrentcontainssignificanttransienthighfrequencycomponent.ThisishappenedbothintheHIFandthenormalswitchingevents,buttheypresentdiff

8、erentcharacteristics.SoHIFandthenormalswitchingeventscanbediscriminatedbyusingthedifferenceofthecorrespondinghighfrequencycomponent.LotsofATPsimulationresultsofHIFwithdifferentfaultresistanceanddifferentkindsofnormalswitch