基于电流双反相量的同杆四回线故障选相方法

为了解决同杆四回线故障情况复杂，跨线故障时无法应用单回线故障选相方法的难题，提出了一种基于故障电流双反相量的同杆四回线故障选相方法。同杆四回线发生一回线内或两回线间跨线故障时，对四回线各相电流进行变换，可得故障相电流的双同及双反相量。通过对故障电流边界条件的分析可知，不同类型故障时故障电流的3个双反相量分别具有不同的幅值和相位特点。以此为基础，提出了在一回线内故障和两回线间跨线故障时能够准确识别故障回线和故障相的同杆四回线故障选相方法。仿真表明本方法在不同的负载电流、过渡电阻、故障位置及故障类型下均能进行有效的故障选相。

A new fault phase detection algorithm for four-circuit transmission lines on the same tower based on double-differential phasors of fault currents

The fault in four-circuit transmission lines is complex, and fault phase detection algorithm of single circuit line can not be used for cross line faults. Aiming at this problem, a method for fault phase selection of four-circuit transmission lines on the same tower is presented based on double-differential phasors of fault currents. Four-summing and double-differential phasors of fault currents can be calculated using a certain transformation matrix for line-line parameter decoupling of four circuit lines. According to fault boundary conditions, the amplitude and phase of three double-differential phasors of fault currents are studied under conditions of different types of faults. Based on this, a novel methodology for fault phase detection for four-circuit transmission lines on the same tower is put forward, which can pick out the fault phases no matter the fault occurs in single line or cross double lines. Simulation results validate that the methodology is correct and reliable under different conditions of load currents, transient resistances, fault point locations and fault types.