Distance Relaying Algorithm for a Single Line-To-Ground Fault on Single Infeed Transmission Lines

Abstract

The work presented in this chapter addresses the problems encountered by the conventional digital distance relay used for the protection of transmission lines fed from one end. To observe its behavior during a high resistance single line-to-ground fault, a laboratory prototype of a three-phase transmission line using equivalent power system components has been developed by the authors. Thereafter, a new digital distance relaying algorithm is presented for the compensation of errors produced by the conventional digital distance relay during a high resistance single line-to-ground fault. The proposed algorithm is based on digital computation of impedance, which uses symmetrical components of three-phase currents and voltages measured at the local end only. The proposed algorithm has been tested using MATLAB/SIMULINK (The MathWorks, Natick, Massachusetts, USA) software for a single line-to-ground fault considering wide variations in fault resistance, fault location, power factor, and short-circuit capacity of the source.