Voltage inversion due to presence of SSSC on adjacent lines and distance relay mal-operation

This paper discusses the distance relay mal-operation in the presence of static synchronous series compensator (SSSC), one of the series connected Flexible Alternating Current Transmission System (FACTS) device. This is done by presenting the measured impedance at the relaying point in the case of SSSC presence at the near end of the line behind. Measured impedance by distance relay is greatly influenced in the presence of SSSC on the transmission line or even in the case of installation of SSSC on the adjacent lines, near end of the line behind. Distance relay tripping characteristic depends on many factors including the power system structural conditions and the pre-fault loading, the ground fault resistance, and SSSC structural and controlling parameters.