计及系统参数和负荷电流影响的故障测距方法  

A Fault Location Method Considering Impact of System Parameters and Load Current

作　　者：张洪喜[1] 徐海洋 卜立之 徐晓春[1] 黄涛[1] ZHANG Hongxi;XU Haiyang;BU Lizhi;XU Xiaochun;HUANG Tao(NR Electric Co.,Ltd.,Nanjing 211102,China)

机构地区：[1]南京南瑞继保电气有限公司,江苏南京211102

出　　处：《山东电力技术》2023年第1期59-64,80,共7页Shandong Electric Power

基　　金：国家电网有限公司科技项目“适用于高比例电力电子设备接入电网的继电保护技术研究”(1200/2020-02003B)。

摘　　要：单端测距由于其独特优势而广泛应用于线路故障测距中。为简化运算,常规单端测距对系统参数等做了近似假设,测距精度会受到一定程度的影响。对常规单端测距算法进行分析,找出影响测距精度的因素,提出一种计及系统参数和负荷电流影响的测距方法。首先根据叠加原理实时计算系统阻抗,并利用系统阻抗和线路阻抗计算故障电流分配系数;再利用故障前后电流变化量计算保护安装处故障电流分量,进而结合电流分配系数计算故障点故障电流;然后根据基尔霍夫电压定律得到关于故障位置系数和过渡电阻两个未知数的复数方程,求方程的解并去除伪根。该方法实时计算系统阻抗,并消除负荷电流的影响,同时考虑了双回线邻线互感的影响。通过MATLAB仿真分析,验证本文提出的改进测距算法能有效提高测距精度。Single terminal fault location is widely used in the transmission line protection because of its unique advantages.The conventional single terminal fault location makes approximate assumptions on the system parameters to simplify the calculation,and the accuracy of fault location will be affected to a certain extent.Based on the study of the current single terminal fault location principle,an improved fault location algorithm was proposed.Firstly,the system impedance was calculated in real time according to the superposition principle,and the fault current distribution coefficient was calculated by using the system impedance and line impedance.Then,the fault current at the fault point was calculated by combining the current distribution coefficient.Finally,the complex equation about the two unknowns of fault location coefficient and transition resistance was obtained according to Kirchhoff’s voltage law,the solution of the equation was obtained and the pseudo roots were removed.The proposed method calculates the system impedance in real time,eliminates the influence of load current,and considers the influence of mutual inductance of adjacent lines of double circuit lines.Through MATLAB simulation,it is verified that the improved algorithm proposed can effectively improve the accuracy of fault location.

关 键 词：故障测距 过渡电阻 系统阻抗 分配系数 邻线互感 

分 类 号：TM762[电气工程—电力系统及自动化]