P.MaryJeyaseeli, R.Gabriel Germans
Due to the development of Power Electronic devices, various FACTS devices such as STATCOM, SSSC, UPFC and IPFC are now installed in transmission line so as to improve the stability, voltage control and power flow control.Distance Relays are the unique devices which are used to protect the transmission line from various shunt faults. The reach of the distance relay is independent of the types of fault when compared to the over current protection.When a FACTS device, say, IPFC is incorporated in order to enhance the power flow control, voltage control, etc., on existing transmission line, it will result in significant change in impedance. This in turn will lead to mal operation of distance relay, as the Distance Relays are sensitive to apparent impedance seen by the relay and zones.This paper analyses the impacts of IPFC in apparent impedance seen by the Distance relay for various shunt faults.