Effects of STATCOM on Distance Relay Tripping Characteristic

This paper presents the measured impedance at the relaying point in the presence of a shunt flexible alternating current transmission system (FACTS) device, i.e. STATic synchronous COMpensator (STATCOM). The presence of STATCOM on a transmission line has a great influence on the tripping characteristic of distance relays. Distance relay tripping characteristic itself depends on the power system structural conditions, i.e. short circuit levels at the line ends, pre-fault conditions, i.e. load angle and voltage magnitude ratio of the line ends, and especially the earth fault resistance. In the presence of STATCOM, its controlling parameters as well as its installation location also affect the tripping characteristic. Here, the measured impedance at the relaying point is calculated due to the mentioned effective parameters