Abstract

This paper presents the application of Unified Power Flow Controller (UPFC) in order to simultaneously power flow control, voltage support and also transient stability improvement at a Single-Machine Infinite-Bus (SMIB) power system installed with UPFC. In practical systems, the conventional PI type controllers are considered to control UPFC. In order to overcome the drawbacks of the conventional PI controllers, numerous techniques have been proposed in literatures. In this paper, PID type controller is considered for UPFC control and the parameters of the proposed PID controller are obtained using Particle Swarm Optimization (PSO). To show effectiveness of PID controller, a PI type controller optimized by PSO is designed in order to compare it with the proposed PID controller. The simulation results visibly show the validity of PID controller in comparison with PI controller.

Key words: Flexible AC transmission systems, Unified Power Flow Controller, power flow control, voltage control, transient stability enhancement, low frequency oscillations damping.