Voltage inversion due to SSSC presence on second circuit of double circuit line causing distance relay mal-operation

This paper discusses the distance relay mal-operation in the case of installation of Static Synchronous Series Compensator (SSSC) which is categorized as a series connected Flexible Alternating Current Transmission System (FACTS) device, on second circuit of a double circuit transmission line. This is done by presenting the measured impedance at the relaying point in the case of SSSC presence at the near end of the second circuit. Distance relay tripping characteristic is greatly influenced in the presence of SSSC on the transmission line or even in the case of installing SSSC on the near end of the second circuit. Distance relay tripping characteristic depends on many factors including power system structural conditions and the pre-fault loading, the ground fault resistance, and SSSC structural and controlling parameters.