Dynamic performance of distance relay for series compensated transmission lines using Real Time Digital Simulator (RTDSNsup>TM)

Series capacitors are installed in the power system for various reasons like to increase power transfer capacity, to improve the system stability, to reduce system losses, to improve voltage regulation and flexible power flow control. But it also affects the performance of the conventional distance relay and causes certain protection issues. This paper briefly discusses the problems like voltage inversion, current inversion, overreach and under reach during the fault conditions on the series compensated lines and how the distance relays can mal-operate, by using RTDS^TM. Before installing the relay in the actual system, it is possible to make compromised settings for relay, by understanding its performance due to the above problems and prevent relay to be mal-operated.