应用STATCOM的DFIG风力发电机低电压穿越能力分析

针对DFIG（double fed induction generator）风电机组低电压穿越能力（LVRT，low voltage ride through）问题，笔者基于STATCOM研究了一种电压外环与电流内环相结合的双闭环反馈控制策略，并仿真验证了所提出方法的有效性。将STATCOM分别安装风电机组机端、并网点高压侧和低压侧，且设置不同电压跌落深度，比较其补偿效果。实验结果表明，安装在风电机组机端时补偿效果最好。在电网电压跌落时，STATCOM能快速为电网输入无功，抬高风力机的机端电压，从而提高风电场的LVRT能力，从STATCOM输出无功大小和风电场机端电压被抬升的比例两方面分析，对于不同深度的电压跌落，STATCOM补偿效果都较为显著。

Analysis of low voltage ride through capability of double fedinduction generator with STATCOM

To improve the low voltage ride through(LVRT) capability on double fed induction generator(DFIG), we developed a double closed-loop feedback control strategy combining voltage outer loop with current inner ring on the basis of STATCOM, and verified its effectiveness through simulation. In the simulations, STATCOMs were respectively installed at the terminal of wind generator, the high voltage side and the low voltage side of common coupling point. And then different depths of voltage drop were added to the grid, and different compensation effects were compared and discussed. Experimental results suggest that the compensation effect is the best when STATCOM is installed at the wind generator terminal. When the voltage drops, STATCOMs can provide power grid with reactive power quickly, raise the voltage of the wind turbine generator, and improve the LVRT capability of wind farms. In the aspects of STATCOM output reactive power and rising percentages of wind farm terminal voltage, the compensation effect of STATCOM is significant for different depths of voltage drop.