Measured impedance by distance relay for inter phase faults in presence of TCSC on next line

This paper discusses the measured impedance by distance relay in the presence of thyristor controlled series compensator (TCSC), one of the series connected flexible alternating current transmission system (FACTS) devices, on the next line, in the case of inter phase, phase to phase and three phase, faults. Especial attention is paid to the over-reaching problem. The measured impedance at the relaying point is greatly influenced in the presence of TCSC on the protected line or even on the near end of the next line. The measured impedance depends on many factors including the power system structural conditions, pre-fault loading, the fault resistance, and TCSC compensation degree.