Comparison of the effects of two flatness based control methods for STATCOM on improving stability in power systems including DFIG based wind farms

Power grids are complex, interconnected and nonlinear systems, and this will be more severe when they are subjected to high wind resources penetration. Static synchronous compensators (STATCOM) are used to improve voltage regulation and to meet grid codes in power systems, including doubly fed induction generators (DFIG) based wind farms. Despite the nonlinear nature of STATCOM, the conventional control method in them is based on linear PI controllers with constant gains, which they cannot guarantee the optimal performance for STATCOM. In this paper, a comparison has been performed between two nonlinear control methods based on differential flatness theory for static synchronous compensators in the WSCC system includes DFIG based wind farms and simulation results demonstrate the effective performance of both methods in comparison with the conventional linear control method.