利用单端电流的同杆双回线准确故障定位研究

基于线路分布参数模型,提出了一种利用单端工频电流量的同杆双回线准确测距算法:通过同杆双回线解耦可以得到同向和反向分量,其中反向分量与系统参数无关,并且反向各序电流分布系数是只包含故障距离x的函数。再根据不同故障的反序电流、电压边界条件,可以给出各种双回线接地故障(单线三相故障和同名跨线故障除外)的测距算法。该算法原理上不受过渡电阻、系统阻抗、分布电容的影响。并且由于算法只利用电流量,从而不受电压互感器传变特性的影响。并从理论上证明了测距精度不受电流互感器特性的影响。测距方程求解不存在伪根,具有唯一解。仿真计算结果表明,该算法具有较高的测距精度,最大测距误差仅为0.15%,理论上能够满足高压和超高压输电线路的测距要求。

AN ACCURATE FAULT LOCATION ALGORITHM FOR PARALLEL TRANSMISSION LINES USING ONE-TERMINAL CURRENT

Based on distributed parameter model,an accurate fault location algorithm for parallel transmission lines is described.Only using one-terminal current,shunt capacitance and complicated mutual coupling are taken into consideration in the algorithm.Common components and differential components are introduced into the algorithm to decouple mutual electromagnetic effect between circuits.Because the differential component network is just constituted by parallel transmission lines and its terminal voltages are zero,voltage distribution along differential component network can be calculated by current only.According to the boundary conditions of fault point and the transmission line parameters difference between positive sequence and zero sequence of differential component network,the equation of fault location can be founded.Theoretically,the proposed algorithm is independent of source impedance,fault resistance,shunt capacitance,and mutual coupling between lines.Since voltages are not be used in the algorithm,the measurement error of PT and CT will not affect on location accuracy.Computer simulation results using ATP show that the algorithm obtains high accuracy,and the maximal error is less than 0.15%.