A Fast Method for Fault Phase Selection Based on the Fitting Error of Transmission Line Differential Equation Algorithm

Abstract

A new fast method for fault phase selection which can apply to the differential equation algorithm of transmission lines is proposed in this paper. Six kinds of transmission line differential equations are established to describe different types of single-phase fault and phase to phase fault which can be solved by the least square method. The least-squares fitting error of the differential equation which is consistent with the real fault type is smaller, while others are bigger. A fault phase identification method by comparing the relative size of fitting error when solving differential equations under different fault types is proposed. The simulation results show that the proposed method can quickly identify any types and phases of faults with a typical time of 5~6ms and can be unaffected by the fault location and fault resistance. Meanwhile, the method could also work in the weak infeed conditions and has sufficient reliability.