基于零序电流与电压相位差变化的灵活接地系统故障选线方法  

Fault Line Detection Method for Flexible Grounding System Based on Changes of Phase Difference Between Zero Sequence Current and Voltage

作　　者：李建蕊 李永丽[1] 王伟康 宋金钊 张云柯[1] LI Jianrui;LI Yongli;WANG Weikang;SONG Jinzhao;ZHANG Yunke(Key Laboratory of Smart Grid(Tianjin University),Ministry of Education,Nankai District,Tianjin 300072,China)

机构地区：[1]智能电网教育部重点实验室(天津大学),天津市南开区300072

出　　处：《电网技术》2021年第12期4847-4855,共9页Power System Technology

基　　金：国家重点研发计划项目(2016YFB0900603);国家电网有限公司科技项目(52094017000W)。

摘　　要：目前灵活接地系统大多采用定时限零序过电流保护,高阻接地故障时保护存在易拒动的问题。为解决此问题,提出了基于零序电流与电压相位差变化的选线方法。基于灵活接地系统单相接地故障的零序等效电路,分析了并联小电阻投入前后的电气量变化特征,即非故障线路始端零序电流与母线零序电压相位差不变,而对于故障线路此相位差发生变化,同时分析了过渡电阻对电气量变化特征的影响,发现过渡电阻只影响母线零序电压相位变化量,而对各线路始端零序电流与母线零序电压相位差的变化量无影响,据此提出该选线方法。该方法利用了并联小电阻投入前后电气量的变化特征,无需其他馈线的电气量即可判定故障线路。仿真实验表明该方法在高阻接地故障时仍能准确选线。At present,the definite time limit zero sequence overcurrent protection is mostly used in the flexible grounding system,but it is easy to be refused when high resistance grounding fault occurs.A line detection method is proposed in order to solve this problem.This paper analyzes the features of electrical quantity changes before and after the input of the parallel resistance,i.e.,the phase difference between zero sequence current of the non-fault line and zero sequence voltage of the bus bar remain constant,but for the fault line,this phase difference changes.Besides,it is found that the transition resistance only affects the phase change of zero sequence voltage of the bus,but has no effect on the phase difference between the zero sequence current of each line and the zero sequence voltage of the bus.The proposed method makes use of the change features of electrical quantity,and the fault line can be determined without using the electrical quantity of the other feeders.The simulation results show that the method is not affected by the transition resistance,and can still accurately select the fault line when the high resistance grounding fault occurs.

关 键 词：灵活接地方式 高阻接地故障 相位差 电气量变化特征 故障选线 

分 类 号：TM721[电气工程—电力系统及自动化]