Modified design of distance relay for series compensated transmission line

Conventional distance relay measures positive sequence impedance for protecting transmission line from short circuit faults. Series compensation improves performance of transmission line but effect on positive sequence impedance of network considerably. It results in mal-operation of distance relay. The proposed protective scheme is able to provide dependable back up protection to series compensated transmission line against all types of faults in system. It applies mutual impedance between transmission line phases as well as positive sequence impedance. The MATLAB/SIMULINK simulation is used to simulate this system. Simulation results shows behaviour of series capacitor under various fault condition and approve the performance of proposed scheme in protection of series compensated transmission line.