Control Interaction of STATCOM and Type-4 Wind Turbines

STATCOM is popularly used to provide reactive power and voltage support for wind farms. However, unwanted interaction of STATCOM and wind farm may occur. This paper aims to analyze the interaction using electromagnetic transient (EMT) simulation and linear system analysis. A data-driven approach is proposed to identify the linear model using the EMT simulation test bed. The entire system is viewed as a feedback system with a plant model and the STATCOM control. Frequency responses of the plant model is obtained using the harmonic injection method. A linear model is then identified via frequency-domain data fitting. With the linear model, stability analysis for different control parameters is carried out using the root-locus method. The proposed method is tested for a type-4 wind farm system. EMT simulation results verify the accuracy of the stability analysis.