Characteristics of VSCF wind turbines under voltage disturbance

The wind turbines is often influenced by voltage disturbance because of voltage instability under the weakpower grids. This paper proposes a method for a variable speed constant frequency(VSCF) wind turbine with doubly-fed induction generator (DFIG) to stay connected to the grid during voltage disturbance. The keypoint of the method is to limit the inrush current in the rotor and the voltage in the DC bus in order to protect the wind turbines and the weak power grids. Then a detailed DFIG model is built and a control strategy is propsoed. In order to regulate network voltage, stabilize weak network, the DFIG using the proposed method can supply reactive power fast, hold system supply stability, reduce risk of voltage collapse and network splitting. Finally, the performance of the new control through severe voltage disturbance conditions is demonstrated by simulation.