Effect of Statcom on Measured Impedance by Distance Relay in Double-Circuit Lines

This paper presents the measured impedance at the relaying point in the presence of static synchronous compensator (STATCOM), a shunt connected flexible alternating current transmission system (FACTS) device, on a double circuit transmission line. The presence of STATCOM on a line has a great influence on the measured impedance by distance relays. The measured impedance by a distance relay itself depends on the power system structural conditions, pre-fault loading, and especially the earth fault resistance. In the presence of STATCOM, its structural and controlling parameters as well as its installation location affect the measured impedance. The measured impedance at relaying point is presented due to the concerning parameters.