改进的配电网双馈风电场电压控制策略

Improved Voltage Control Strategy of Doubly-fed Induction Generators Wind Farm in Distribution Networks

结合双馈风电机组(doubly-fed induction generators,DFIG)的运行特点,提出了一种改进的适用于与配电网连接的双馈风电场的电压控制策略,其中既包括了传统的通过无功功率控制电网电压的方法,也包括电网负序电压的补偿控制策略。以双馈风电系统的功率关系为基础,给出双馈风电机组不同运行状态下的无功功率的计算方法,阐述双馈风电机组的无功功率控制方法及通过风电场无功功率控制电网电压的方法。针对电网电压不平衡的情况,给出通过双馈风电机组抑制电网负序电压影响的控制方法,分析了双馈机组的控制电网负序电压的限制条件和控制策略。由双馈风电机组构成的与配电网连接的风电场的仿真结果验证了所提出的电压控制策略的有效性,仿真结果表明这种电压控制方法可以有效地提高电网及风电场运行的稳定性。

An improved grid voltage control strategy of doubly-fed induction generators （DFIG） wind farm in distribution networks is proposed based on the DFIG operation characteristic. The voltage control method through reactive power and negative sequence voltage compensation method are included. Based on the power relationships of DFIG system, a modified reactive power limit calculation method in different operation states of DFIG is analyzed and the reactive power control strategies of wind farm and DFIG are introduced. The negative sequence voltage compensation control strategy of DFIG is proposed for unbalanced grid voltage condition. The compensation limit is given based on the current margins and DC voltage limitation of grid side converter. The distribution algorithms of negative sequence current in the wind farm and in the generator system are also introduced. The proposed grid voltage control strategy is verified by simulation results. Simulation results show that with the grid voltage control method the stability of the wind farm and power grid is improved.