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

This paper presents the effects of Static Var Compensator (SVC), one of the shunt connected Flexible Alternating Current Transmission System (FACTS) devices, on the measured impedance at the relaying point in the case of 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, line structural conditions, and specially the fault resistance. In the presence of SVC, in addition to its compensation current, its installation point also affects the measured impedance at the relaying point. The variation of the measured impedance for different installation points and amounts of injected or absorbed reactive power will also be investigated.