小电阻接地系统单相接地故障的处理与区段定位

Single Phase Grounding Fault Treatment and Section Location in Small Resistance Grounding System

通过对配电网小电阻接地系统单相接地故障各电气特征量的分析,探讨了小电阻接地系统因无法识别故障性质造成的供电可靠性低、发生高阻接地故障时零序保护拒动和无法实施故障区段定位的难题,提出了基于智能电阻接地成套装置和节点零序电流幅值比较模型的小电阻接地系统单相接地故障处理与区段定位方法。通过多电气特征量关联启动法对故障进行识别处理,采用差异化延时消弧法使瞬时性故障快速恢复,提高了供电可靠性。当发生永久性接地故障时,通过智能电阻接地装置向配电自动化主站上报故障选线报文,利用故障馈线中的配电自动化终端获取各节点的零序电流值,构建基于节点零序电流比较法的区段定位判据,实现故障区段定位。利用MATLAB/Simulink仿真环境搭建了配电网经电阻接地方式的故障区域定位模型,仿真试验表明,该方法能确定故障上下游的参数特征及对故障区段进行有效定位,可为配电网小电阻接地系统单相接地故障处理问题的解决提供有效方案。

Through the analysis of each electrical characteristic quantity of single-phase grounding fault in the small resistance grounding system of the distribution network,the problems of low power supply reliability,ze⁃ro sequence protection rejection and failure section positioning in the case of high resistance grounding fault caused by the failure nature of the small resistance grounding system are discussed.A method of single-phase grounding fault treatment and section location of small resistance grounding system based on intelligent resis⁃tance grounding equipment and node zero sequence current amplitude comparison model is proposed.The fault is identified and handled by the method of multi electric characteristic quantity correlation and start-up,and the instantaneous fault is quickly recovered by the method of differential delay,which improves the reliability of power supply.When a permanent ground fault occurs,the intelligent resistance grounding device reports a fault line selection message to the distribution automation main station,the distribution automation terminal in thefault feeder obtains the zero sequence current value of each node,and a section positioning judgment based on the node zero sequence current comparison method is constructed to realize the fault section positioning.Using MATLAB/Simulink simulation environment,the grounding fault area location model of distribution network grounded by intelligent resistance is built.This method can determine the parameter characteristics of upstream and downstream fault and section effectivety.It provides an an effective solution to solve the problem of intelli⁃gent processing of single-phaes grounding fault in small resistance grounding system of distribution network.