Evaluation of power system stability by UPFC via two shunt voltage-source converters and a series capacitor

In this paper, the effects of a newly presented unified power flow controller (UPFC) structure, which is based on two shunt voltage-source converters and a series capacitor, is investigated on the dynamic stability of power system. To reach to this purpose, it was suggested a non-linear dynamic model for a sample power system that a proposed UPFC was installed on. From non-linear dynamic model, it was suggested a linear dynamic model and modified Heffron-Philips model. Then, by modifying of damping controller for proposed UPFC and regulating UPFC controller parameters by phase compensation technique, the most appropriate and effective entering signal was chosen among controlling signals of proposed UPFC by different technique. The validity of the theoretical facts is then well confirmed by simulation results obtained in MATLAB/Simulink.