不对称配电网的单相接地故障分析及动态接地方式研究  

Single-Phase Grounding Fault Analysis and Dynamic Grounding Method Research of Asymmetrical Distribution Network

作　　者：杨舍近 李军 安东亮 狄京元 马心良 李必伟 YANG Shejin;LI Jun;AN Dongliang;DI Jingyuan;MA Xinliang;LI Biwei(State Gird Henan Electric Power Company Luohe Power Supply Company,Luohe 462000,China;Electrical and Information Engineering and Technology Changsha University of Science and Technology,Changsha 410000,China;Changsha Xinchang Electric Technology Co.,Ltd.,Changsha 410000,China)

机构地区：[1]国网河南省电力公司漯河供电局,河南漯河462000 [2]长沙理工大学电气与信息工程学院,长沙410114 [3]长沙信长电力科技有限公司,长沙410000

出　　处：《电瓷避雷器》2022年第4期91-98,共8页Insulators and Surge Arresters

摘　　要：配电网线路的对地电容不对称、所带负载大小以及检测设备所存在的误差,使得配电网中性点始终存在一定的位移电压。研究了小电流接地系统在不对称情况下发生单相接地故障的零序电流分布情况,根据现有小电流接地系统所存在的故障特征分析,提出了动态接地方式。该方式通过中性点电压位移增量以及线路零序电流的变化作为选线装置启动判据,判断故障性质后动态切换中性点接地方式,选出并切除故障线路。该方式在漯河真型试验场进行了单相接地故障检测,经试验验证得出该方式在不对称度为3%的情况下,故障电阻识别能力可达到3500Ω,能有效解决消弧线圈系统高阻选线难、故障识别不准确的问题。The asymmetry of the capacitance to the ground of the distribution network,the size of the load carried and the error of the detection equipment,make the neutral point of the distribution network always have a certain displacement voltage.The author studies the zero-sequence current distribution of a single-phase grounding fault in a small-current grounding system in an asymmetrical situation.Based on the analysis of the fault characteristics of the existing small-current grounding system,a dynamic grounding method is proposed.It uses the neutral point voltage displacement increment and the line zero sequence current change as the starting criterion of the line selection device.After judging the nature of the fault,the neutral point grounding mode is dynamically switched,and the fault line is selected and removed.The method has carried out single-phase ground fault detection at the Luohe True Proving Ground,and it has been verified by experiments that when the asymmetry of this method is 3%,the fault resistance identification capability can reach 3500Ω,which can effectively solve the problems of difficult high resistance line selection and inaccurate fault identification of arc suppression coil system.

关 键 词：不对称电网 小电流接地系统 动态接地 高阻选线 故障识别 

分 类 号：TM862[电气工程—高电压与绝缘技术]