Modeling and Simulation of Multi-machine System Using UPFC for Enhancing Transient Stability

In this paper, transient stability of IEEE 9- bus system combined with Unified Power Flow Controller (UPFC), has been accomplished. UPFC based on Voltage Source Controller (VSC) has a higher switching frequency, an obvious voltage harmonic and a lower voltage level. Under a symmetrical three-phase short circuit with a different fault locations were used and the load angle variation also studied to test the control performance. The multi machine system combined with UPFC controller, perform outstanding to reduce damping oscillation in power system observed in results of simulation.