Multi-stage Reactive Power and Voltage Control Strategy of DFIG Based on Wind Farms

In order to solve the voltage stability issue caused by large-scale wind farm integrated power grid, a new multi-stage coordinated control strategy of reactive power and voltage is proposed. The switching scheme of capacitor bank is pre-performed based on the predicted wind power firstly. Then in steady state, the reactive power of wind farm is regulated to control the reactive power and voltage by analyzing the relation between active power and reactive power of DFIG. In addition, SVC is controlled to make full use of its reactive power capability in fault state, and the voltage overshoot is avoided by limited power output after fault, which show the effectiveness of coordinated control reactive power and voltage overall. In the end, the validity and feasibility of proposed scheme are verified by simulation results of a practical wind farm.