基于负序电流的同杆多回线故障测距方法

New Fault Location Algorithm for Muti-loop Transmission Lines Based on Negative-sequence Current

多回线路之间存在的线间零序互阻抗使得多回线发生单回线不对称故障的测距变得困难。为此,充分分析了多回线上发生单回线不对称故障时负序网络的特点,并通过网络拓扑的等效变换,计算出各回线上负序电流的表达式,进一步得到回线间的负序电流比值。研究发现,回线间的负序电流比值是只和故障位置相关的一次函数,利用此关系以及实测的各回线负序电流值,建立一次方程,便可准确计算出单回线不对称故障的故障位置。该算法不受过渡电阻的影响,各类故障测距公式统一,简便易行,可以应用于多回线上单回线非对称故障时的测距,仿真验证表明其效果良好。

Fault location determing became difficult because of the zero-sequence mutual impedance between dif ferent lines while single line asymmetry fault occurs in muti-loop transmission lines. This paper analyzes the character of the negative sequence current network. Based on the equivalent of negative-sequence network, the negative current formula can be figured out, then the ratio of different loops＇ s negative current can be obtained,which is a linear function only related to the fault location variable,according to the relations and the measured values of currents, equation is set up and location variable can be solved. The algorithm is simple and convenient, not affected by the transition resistance, and all kinds of faults location formulas are unified, can be used for asymmetry fault location of single line in muti-loop transmission lines, the simulation testifies the v lidity of the method.