Distance Relay Tripping Characteristic in Presence of SSSC on Next Line

This paper discusses the distance relay tripping characteristic 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 and pays especial attention to the over-reaching problem. This is done by presenting the measured impedance at the relaying point in the case of SSSC presence at the near end of the next line. Distance relay tripping characteristic is greatly influenced in the presence of SSSC on the transmission line or even in the case of installation of SSSC on the near end of the next line. Distance relay tripping characteristic depends on many factors including the power system structural conditions, the pre-fault loading, the ground fault resistance, SSSC controlling parameters, and the coupling transformer impedance.