基于导纳不对称原理的小电流接地系统选线方案  

Fault line selection scheme in small current grounding system based on admittance asymmetry principle

作　　者：韦莉珊 贾文超 焦彦军[1] WEI Lishan;JIA Wenchao;JIAO Yanjun(Department of Electrical Engineering,North China Electric Power University,Baoding 071003,China)

机构地区：[1]华北电力大学电力工程系,河北保定071003

出　　处：《电力自动化设备》2020年第3期162-167,共6页Electric Power Automation Equipment

基　　金：中央高校基本科研业务费专项资金资助项目(2016-MS87)。

摘　　要：为了解决目前仍然存在的小电流接地系统单相接地故障选线难的问题,提出了一种运用导纳不对称参数作为判据的故障选线方案。该方案借鉴了主动保护的思想,通过并联中电阻改变中性点经消弧线圈接地系统故障后的结构,找出故障线路与非故障线路的导纳不对称参数差异。所构造的不对称参数可以衡量线路的导纳不对称程度,理论分析以及PSCAD仿真结果表明:健全线路的导纳不对称度为0,故障线路导纳不对称度不为0且大于1,通过两者差异可以实现准确选线。该方案无需设置动作门槛,灵敏性较高,且导纳不对称参数理论上不受过渡电阻影响。In order to solve the difficulty of fault line selection in small current grounding system,a fault line selection scheme based on admittance asymmetry parameter is proposed,which draws on the idea of active protection. The difference of admittance asymmetry parameters between faulty line and healthy line is found out by changing the neutral grounding mode after the fault by the medium resistance. The unsymmetrical parameters can be used to measure the degree of admittance asymmetry. Results of the theoretical analysis and PSCAD simulation show that the admittance asymmetry of healthy line is 0,while that of faulty line is not 0 and bigger than 1,the faulty line can be selected accurately through the difference between them. The proposed scheme has high sensitivity and doesn’t need to set the action threshold. The admittance asymmetry parameter is not affected by the transition resistance theoretically.

关 键 词：小电流接地系统 故障选线 导纳不对称度 中电阻 

分 类 号：TM77[电气工程—电力系统及自动化]