Impact of shunt capacitance of a SSSC-compensated transmission line on performance of distance relays

Taking the shunt capacitance of a transmission line, compensated by a static synchronous series compensator (SSSC), as well as other affecting factors into account, and in case of a single line to ground (SLG) fault when the compensator resides in the fault path, this paper derives a precise formula for the apparent impedance seen by the ground element of a distance relay. In the case where the SSSC is found at the local end and providing reactive power compensation of the line, ideal tripping characteristics of the relay are acquired for different degrees of compensation through the impedance formula. In addition, the research investigates the impact of ignoring the shunt capacitance of the line on the relay under and overreach.