Measured impedance by distance relay for inter phase faults in presence of STATCOM

This paper presents the effects of STATic synchronous COMpensator (STATCOM), one of the shunt connected Flexible Alternating Current Transmission System (FACTS) devices, on the measured impedance at the relaying point in the case of the inter phase, phase to phase and three phase, faults. The measured impedance at the relaying point is affected by several factors, including the line pre-fault loading, the line structural conditions, and specially the fault resistance. In the presence of STATCOM, in addition to its amount of injected or absorbed reactive power, its installation point also affects the measured impedance. The variation of the measured impedance for different installation points and amounts of injected or absorbed reactive power would also be studied.