Simulation of Distance Relay Operation on Fault Condition in MATLAB Software/Simulink

Abstract

In this paper a distance relay is simulated in the proposed transmission line protection which is combination of overhead line and significant part of underground cable. Transmission line is modeled as distributed parameter instead of lumped parameter to have more accurate analysis compare to conventional analysis. Voltage and current are sampled at relay point. But, high charging current of cable affects distance relay operation. Using appropriate filtering can reduce charging current effect on distance relay. Simulated impedance will be compared with positive sequence impedance of power system in order to evaluate simulated relay. The relay shows a good result for faults in zone 1, but high resistance faults force distance relay to mis-operation.