双馈型风电场群无功分层协调控制策略

Coordination Strategy of Reactive Power Control on Wind Farms Based Doubly Fed Induction Generator

针对目前风电场群无功补偿多以单场独立控制为主,且各风场间缺乏无功协调控制机制的特点,提出一种适用于双馈型风电场群的分层无功补偿策略,特别关注了双馈型风电机组/风电场的无功调控能力,并基于风电功率波动特性分析,根据当前时刻风电有功出力,对其下一时刻的无功调控能力范围进行了概率评估。该策略分3层实施:场群层,根据场群汇集站中枢点电压确定整个场群无功补偿任务;子场层,基于多目标函数模型及遗传算法对各单场分配无功任务;机组层,各单场控制子站实施上层控制下达的指令,并完成场内风机无功分配任务。算例研究表明,该控制策略能够实现各风场无功补偿任务的优化分配,充分利用了双馈风机的无功调控能力,可提高风电场群的静态电压稳定性。

Currently reactive power compensation strategies of wind farms in a same wind power base are mainly controlled by every farm independently, and there is a lack of coordinated control mechanism between them. The aim of the proposed work is to present an optimal multilevel control system which mainly allows the doubly fed induction generators （DFIG） to participate at reactive power compensation in wind farms. According to the current active power output, this paper made a probability assessment on reactive power capacity range of DFIGs for next time internal. First, the reference values of reactive power were estimated by monitoring the voltage of central point. Second, the optimal reference values of reactive power for each wind farm at each point of common coupling （PCC） were calculated by genetic algorithm. The proposed multi-level control system recalculates the available reserve of the reactive power of DFIGs to determine the optimal references. The simulation results show a better performance of the proposed model and strategy in respects of using the reactive power capacity of DFIGs and stabilizing the static voltage of wind farms.