五次谐波法对小电流接地系统的故障定位【摘要】在我国3~66kV配电网中，广泛采用小接地电流系统，而此系统发生最多的是单相接地故障，所以如何快速准确地检测出故障线路一直是电力系统继电保护的重要研究课题。小电流接地系统是我国35kV及以下电网最常用的接线方式，而对于小电流接地系统的故障定位又有许多方法，有零序电流比幅比相法，有功法，残流增量法，“S”注入法等等。通过对这些方法的分析，总结了影响接地故障选线准确性的因素。而本文则是根据故障点前后零序电流五次谐波大小的不同，设定一定的门槛值，通过相邻两个测量点数据比较，就可以判断故障点的位置，无须母线端信息采集、分析。是运用了五次谐波法来对小电流接地系统的故障定位。针对基于五次谐波电流的单相接地故障选线装置,由于系统中五次谐波含量不高,以及负荷中谐波源的影响,整定困难,实际选线精度不高的问题。系统地分析了发生单相接地前后故障回路、非故障回路中五次谐波电流变化特点,提出了基于五次谐波电流变化特征的单相接地故障选线方法,仿真结果表明,该方法有效可行。关键字：小电流接地系统；谐波；相位；无线；五次谐波；消弧线圈五次谐波法对小电流接地系统的故障定位【Abstract】Inourcountry3~66kVindistributionnetwork,widelyusedinsmallcurrentgroundingsystem,andthissystemisthelargestsingle-phasegroundingfault,sohowtodetectthefaultlinequicklyandaccuratelyisalwaystherelayprotectionofpowersystemtheimportantresearchtopic.Smallcurrentgroundingsystemisourcountry35kVandbelowthepowersystemthemostcommonlyusedconnectionmode,andforsmallcurrentgroundingsystemfaultlocationandtherearemanyways,zerosequencecurrentratioamplitudephasemethod,method,theremnantcurrentincrementmethod,"S"intothemethod.Throughtheseanalyses,summarizestheeffectsofgroundfaultlineselectionaccuracyfactors.Butthisarticleisaccordingtothefaultpointandzerosequencecurrentfiveharmonicsofdifferentsizes,thesettingofacertainthresholdvalue,throughtwoadjacentpointsofmeasurementdata,wecanjudgethefaultpoint,nobusterminalinformationcollection,analysis.Istheuseofthefiveharmonicmethodforsmallcurrentgroundingsystemfaultlocation.Basedonthefiveharmoniccurrentofsingle-phasegroundingfaultlineselectiondeviceinthesystem,thefiveharmoniccontentisnothigh,andtheeffectofloadharmonicsources,tuningdifficulties,theactualalignmentprecisionproblem.Systemanalysisofthesinglephasegroundingfaultcircuit,beforeandafterthefaultloopoffiveharmoniccurrentcharacteristics,basedonthefiveharmoniccurrentchangescharacteristicofsinglephasegroundingfaultlineselectionmethod,thesimulationresultsshowthat,themethodisfeasibleandeffective.Keywords:smallcurrentgroundingpowersystem;harmonic;phase;wireless;Fiveharmonic;arcsuppressioncoil目录1引言....................................................12小电流接地系统的简介....................................22.1小电流接地系统的接地特点............................22.2小电流接地系统单相接地的概述........................32.2故障分析............................................43仿真测试................................................73.1设计原理............................................7五次谐波法对小电流接地系统的故障定位3.2判定方法............................................83.3五次谐波法原理......................................93.4五次谐波选线法基本原理简介..........................93.5仿真实验及分析......................................114总结....................................................174.1结论................................................174.2小电流接地系统的选线技术与发展......................17致谢.....................
