Distance relay over-reaching in presence of TCSC on next line considering MOV operation

This paper discusses the distance relay overreaching due the presence of Thyristor Controlled Series Compensator (TCSC), one of the series connected Flexible Alternating Current Transmission System (FACTS) devices, considering its MOV operation. This is done by presenting the measured impedance at the relaying point in the presence of TCSC at the near end of the next line. The measured impedance at the relaying point is greatly influenced in the presence of TCSC on the protected transmission line or even in the presence of TCSC on the near end of the next line. The measured impedance at the relaying point depends on many factors including the power system structural conditions, pre-fault loading, ground fault resistance, and TCSC compensation degree.