风电系统电压跌落故障的解决方案研究

Solutions to Voltage Dip for Wind Power System

主要对风电场电压跌落后的无功补偿和转子过流问题进行深入研究,并提出相应的解决方案。在电压穿越时双馈电机将由无功源变成无功负荷,加剧电网无功负担。因此把无功补偿器STATCOM运用到风电场中,并提出相应的控制策略平衡电网无功。然后针对crowbar电路对转子电流的影响进行分析,得出转子侧电流与转子侧电阻的数学表达式。最后运用STATCOM和crowbar及其相应的控制策略进行仿真。仿真结果验证了电压跌落后STATCOM的无功补偿能力以及crowbar对转子电流的限制能力。

This paper researches on reactive power compensation and rotor over-cun^nt problem in the process of the voltage dip of wind farm, and proposes appropriate solutions to that. In voltage dip, the DFIG will be a load of reactive power instead of a reactive power, which would exacerbate the burden of power system. So this paper applies the var compensator STATCOM to the wind farm, and proposes appropriate control strategies to balance grid reactive power. Then it analyzes the influence from crowbar circuit on rotor current, and get the mathematical expression of the rotor current and rotor side resistance. Finally, it uses the STATCOM and crowbar to simulate the contro! strategy. The simulation results demonstrate that after the voltage dip, the STATCOM is capability to supply re-active power and the crowbar can limit the rotor current.