Dynamic Stability Improvement in Power System with Simultaneously and Coordinated Control of DFIG and UPFC

This paper presents the impact of simultaneous and coordinated control of the unified power flow controller (UPFC) and the doublyfed induction generator (DFIG) on the multimachine power system`s dynamic stability. All UPFC`s main basic PI controllers and its Power Oscillation Damping (POD) supplementary controller have been used. A more complete model of DFIG and both RotorSide Converter (RSC) and GridSide Converter (GSC) dynamics with their PI controllers are considered, too. UPFC and DFIG controllers are simultaneously coordinated and optimized with compromising between their control variables parameters. Particle Swarm Optimization (PSO) algorithm is used to optimize the objective function based on eigenvalues and damping ratio to reach the best parameters and variables of controllers of both UPFC and DFIG. During the studies of permanent and dynamic state, the thermal capacity of the lines and the nominal values of UPFC have also been considered. Simulation results in a 39bus 10machine NewEngland power system show the capability of the applied method. The results demonstrate that coordinated control of UPFC and DFIG tend to more damping system modes oscillation and more stability in the power system.