A New Digital Distance Relaying Algorithm for First-Zone Protection for Series-Compensated Double-Circuit Transmission Lines

This paper proposes a new digital distance relaying algorithm for first-zone protection for series compensated double-circuit transmission lines. The new method uses data from one end of the protected double-circuit lines to calculate the fault distance. It is shown that the new method is independent of load current, remote in feed and source impedances. To validate the proposed scheme, numerous computer simulations have been carried out on a 400-kV, 300-km-long series-compensated double-circuit transmission line using MATLAB/SIMULINK software. Simulation results demonstrate the effectiveness of the proposed scheme since the maximum percentage error is within ±5%.