Positive-Sequence Component Based Directional Relaying Algorithm for Single-Pole Tripping

This paper addresses positive-sequence based protection scheme for series-compensated high-voltage transmission lines during faults in the presence of single-pole tripping (SPT) condition. Directional relaying algorithm based on the angle difference between fault and pre-fault positive-sequence current phasor has been proposed to estimate the fault direction during SPT in transmission lines. The performance of the proposed method has been evaluated by simulating the single-circuit system using EMTDC/PSCAD for various fault scenarios considering compensated and uncompensated transmission line. Discrete Fourier transform technique has been used to estimate the fundamental components. The outcome of different existing conventional directional relaying techniques has been analysed considering SPT, in the presence and absence of voltage and current inversion in the compensated/uncompensated system and compared with the proposed technique. To test the ability of the proposed classifier, the WSCC 9-bus system with capacitor switching and power swing has been tested. Some abnormal operating conditions have also been considered to prove the robustness of the proposed scheme. Simulation studies show that the fault direction estimation algorithm efficiently identifies the direction of fault. The performance of the algorithm shows its consistency and accuracy in estimating the direction of fault during SPT.