Distance Relay Over-Reaching due to Installation of TCSC on Next Line

This paper discusses the distance relay over-reaching in the case of installation of thyristor controlled series compensator (TCSC) which is categorized as a 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 TCSC presence at the near end of the next line. Distance relay tripping characteristic is greatly influenced in the presence of TCSC on the transmission line or even in the case of installation of TCSC on the near end of the next line. Distance relay tripping characteristic depends on many factors including the power system structural conditions and the pre-fault loading, the ground fault resistance, and the TCSC compensation degree