Zone Protection System of Transmission Line by Distance Relay using Matlab/Simulink

This work represented the problems on transmission line in different type of zones. The conventional digital distance relay used for the protection of transmission lines fed from one end. By observing its behavior during a high resistance for single line to ground fault, line to line fault a laboratory prototype of a three-phase transmission line using equivalent power system components has been developed. Therefore, algorithm for digital distance relaying is presented for the station of errors produced by the conventional digital distance relay during a high resistance single line to ground fault or line to line fault. In this paper the 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 distance is divided into zone 1, zone 2 and zone 3. This paper may help to identify the fault on a transmission line and also help to improve the power factor of the system. The proposed algorithm has been tested using MATLAB/SIMULINK software for a single line-to-ground and line-to-line fault which consider wide variations in fault resistance, fault location, power factor, and short-circuit capacity of the source.