基于STATCOM和Crowbar的双馈风电场低电压穿越控制

摘要

针对保障双馈风电机组在因电网故障引起的电压跌落时不离网运行的问题, 通过分析双馈感应发电机的结构与电网电压跌落时双馈风电机组的暂态数学模型, 提出了应用静止同步补偿器 (Static-Synchronous-Compensator, STATCOM) 与撬棒 (Crowbar) 保护电路结合的方案来改善双馈风电机组低压穿越能力.在Matlab/Simulink平台搭建了双馈感应发电机的低压穿越仿真模型, 结果表明:STATCOM可以在电网故障时发出无功功率维持电网电压稳定;Crowbar保护电路可以在电网故障时抑制转子侧过电流.应用STATCOM与Crowbar保护电路可以在电网电压跌落时, 提高双馈风电场的低压穿越能力.%In order to keep the doubly fed induction generator (DFIG) from running off the grid due to the voltage drop caused by power grid failure, a scheme is proposed to improve the low voltage riding through ability of doubly-fed wind turbines by combining static-synchronous-compensator (STATCOM) with Crowbar protection circuit. The structure of doubly-fed induction generator and the transient mathematical model of doubly-fed wind turbines is analyzed in detail. Simulating results show that STATCOM can provide reactive power to maintain the grid voltage stability in the event of a power grid failure; the Crowbar protection circuit can suppress the rotor side during grid faults. The use of STATCOM and Crowbar protection circuits can improve the low-voltage riding through capability of a doubly-fed wind farm when the grid voltage drops.