SVC与桨距角控制改善异步机风电场暂态电压稳定性

研究了改善异步机风电场暂态电压稳定性的措施。基于普通异步机的恒速风电机组是目前世界上应用最为广泛的风电机组之一，由于其发出有功功率的同时吸收无功功率，会导致接入风电地区电网的电压稳定性降低。文中在DIgSILENT/PowerFactory中建立了静止无功补偿器（SVC）控制模型及风电机组桨距角控制模型，通过包含风电场的电力系统仿真计算验证了模型的有效性及其对异步机风电场与电网暂态电压稳定性的贡献。研究结果表明，在接入风电地区电网发生三相短路的大扰动故障时，SVC能够有效地帮助恒速风电机组在故障后恢复电压，提高输出的电磁功率，桨距角控制能够有效地降低恒速风电机组的输入机械功率，以上2种措施能够避免风电机组机械与电磁功率不平衡引起的异步发电机超速及电压失稳;采用SVC及风电机组桨距角控制能够改善异步机风电场的暂态电压稳定性，确保风电机组连续运行及电网安全稳定。

Enhancement of Transient Voltage Stability of Induction Generator Based Wind Farm by SVC and Pitch Control

The measures to enhance transient voltage stability of induction generator based wind farm are studied in this paper. Constant speed wind turbines equipped with induction generator is the most widely used technology in the world so far. The local grid voltage stability will be reduced due to the integration of induction generator based wind farm because the high demand of reactive power absorbed by induction generator. The SVC with its controller model and pitch control model is set up in the power system simulation program DIgSILENT/PowerFactory in this paper. The model validity and the contribution to the transient voltage stability are verified by power system simulation containing large wind farm. Power system simulation results show that the SVC can assist the induction generator restoring the voltage rapidly in the duration of power system large disturbance, ensuring both the voltage stability of the grid and the continuous operation of the wind turbines. They also demonstrate that pitch control of constant speed wind turbines can effectively reduce the wind turbine mechanical power, preventing the wind turbines from over-speeding and transient voltage instability in the duration of power system large disturbance. Finally, it is concluded that the adoption of the SVC and pitch control enhances the transient voltage stability of induction generator based wind farm, ensures the continuous operation of wind turbines and the security and stability of the power network.