Series compensated line protection enhancement by modified pilot relaying schemes

In this paper, a comprehensive analysis of the impact of series capacitor on the performance of communication-aided distance protection schemes of transmission lines is presented. It is shown that not only the series capacitor and its overvoltage protection affect the distance protection of its line, but also the adjacent lines would experience protection problems. Mitigation of this problem is proposed by using new communication-aided schemes. The proposed schemes use the information available at the substation to inhibit relay malfunctions. The performance of the techniques is studied for different series capacitor locations in the transmission line. Real Time Digital Simulator (RTDS) and four sophisticated commercial relays are used for testing. The results verify the impact of series capacitor on the conventional communication-aided schemes and also the effectiveness of the proposed methods