Mitigation of Power System Transients in a Multi-Machine System using Unified Power Flow Controller

Nowadays the Flexible AC Transmission System (FACTS) devices are used in the existing system for better utilization. In this paper modeling and advantages of a series-shunt connected FACTS device i.e. Unified Power Flow Controller (UPFC) with the multi-machine system are discussed. In order to test the effectiveness of these controllers, results are carried out on the basis of mitigation of settling time of power oscillations and transient peaks of line power, bus voltages and rotor angle between two machines respectively for single line to ground and three-phase fault. After a rigorous comparison, it has been observed that three-phase fault is severe than a single line to ground fault. Also, it can be concluded from results that proposed controller damped out the power system oscillations and stabilize the test system and thereby enhancing the stability of a given system.