小电流接地系统的单相接地故障分析

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1、万方数据AbstractNeutralpointnon．effectivelygroundedmodesarewidelyusedinpowerdistributionnetworkinChina．Thesemodescanimprovethereliabilityofpowersuppy．Whenasinglephasetogroundfaultoccurs，thecurrentofthegroundingphaseismuchsmallerthantheloadcurrentandthree—phaselinevoltag

2、eCanstillkeepthesymmetry．Sothesystemcanrunwithfaultsforawhile．Butthefaultphasevoltageposesaseriousthreattothesystem．Inordertoavoidtheexpansionofthescopeoftheaccident，thefaultmustbelocatedandremovedquickly．Themainresearchcontentofthispaperistheproblemoffaultlineselec

3、tionandfaultlocation．Firstly，thispaperdoanin-depthresearchonthesteadyandtransientcharacteristicsofthesystemswhenasingle．phasegroundfaultoccursinthem．Theresultsshowthatthetransientandsteadycharacteristicsarebothcontainsalargenumberoffaultinformation，butthesteadyvalue

4、sareverysmall，SOitwillleadgreaterrorbyusingthem．Thetransientinformationofthesystemsaremoreobviousandnotaffectedbythenon—effectivelygroundingmethod，thereforetheuseoftransientcharacteristicsoflinesismoresignificance．Thewavelettransformisasignalanalysistool，itCandecomp

5、osethesignalintodifferentfrequencebands，whichisconducivetoextractthetransientfaultinformationfromthefeaturefrequencyband．Theresearchonthetheoryofwavelettransformprovidesatheoreticalbasisforthemethodofselectingthefaultline．Finallythesimulationexamplesshowthatthemetho

6、disapplicabletotheneutralnon-groundedsystemandneutralpointviaarCsuppressioncoilsystem．Thestructureofdistributionnetworksismorecomplex，whenthefaultlineiSselected，thefaultpositionisalseneededtolocate．Thispaperproposestheuseofimprovedplantgrowthsimulationalgorithmandth

7、ebatalgorithmtolocatethefaults．Takingintoaccountthefaultinformationiseasilyaffectedbyvariousenvironmentalfactors，Soareasonablemathematicalmodelisestablished．ItCanmakeuseofthePGSAandBA埘t11faulttolerance．ThesimulationresultsshowthatthemethodsCanaccuratelylocatethefaul

8、tsectionintheconditionswithdistortioninformationornon-distortioninformation．Keywords：smallcurrentgroundingsystem；wavelettransform；plantgro