Intelligent Parameter Design-Based Impedance Optimization of STATCOM to Mitigate Resonance in Wind Farms

In certain regions and countries, the static synchronous compensator (STATCOM) is required in large-scale wind farms to provide reactive power support. Due to the limitations and complexity in distributed wind power systems, the STATCOM is considered as an effective and cheap alternative for impedance shaping to mitigate resonance. However, there is still a lack of quantitative stability analysis for practical large-scale wind farms and an optimization approach for the STATCOM impedance to achieve so. Therefore, based on the sequence impedance matrix models of the Type-IV wind turbine generator (WTG) and STATCOM for the network modeling, this article presents a sequence impedance network-based stability analysis for practical wind farms to accurately reveal the stability of wind farms and quantitatively evaluate the damping provided by the STATCOM. A typical wind farm in Western China is exemplified to demonstrate the proposed stability analysis. Then, an intelligent parameter design-based optimization approach for the STATCOM impedance is proposed, which uses the heuristic intelligence algorithm to solve the STATCOM controller parameters to obtain the optimal stability margin of the wind farm under the constraints of desired performance. Finally, a comparison with the understanding-of-models-based optimization method confirms the efficacy of the proposed impedance optimization approach.