考虑风电功率预测的分散式风电场无功控制策略

分散式风电接网模式可以解决集中式并网限电等问题,但对配电网传统运行模式带来挑战。为解决其经济稳定运行难题,提出了一种包含无功预测、无功整定、无功分配的三层新型分散式风电场无功协调控制策略。其中,无功预测层利用物理和统计方法组合预测单台机组未来无功输出能力;无功整定层针对有无无功补偿设备,提出风电机组基于电网无功缺额降出力的自身补偿和多时间尺度协调离散补偿设备、静止无功发生器(SVG)与风电机组共同补偿配电网无功需求方法;无功分配层基于风电功率预测无功功率信息,考虑风速波动性,按照优先级动态筛选风电机组,调节其输出功率以跟踪无功补偿指令。工程算例证明了所提策略可以有效提高电压支撑能力,减小风电场损耗。

Reactive Power Control Strategy for Dispersed Wind Farm Considering Wind Power Forecasting

Dispersed wind power grid connection can resolve the problems caused by centralized grid connection, however, it is a challenge to the traditional power grid scheduling mode. In order to achieve economic and stable operation, a new three-layer reactive power coordinated control strategy including reactive power forecasting, setting and distribution for dispersed wind farm (DWF) is put forward based on wind power forecasting. The reactive power forecasting layer is used to forecast future reactive output of single wind turbine based on physical and statistical combination method. In the reactive power setting layer, considering reactive power compensation devices, a diminishing active power method is adopted. Depending on the required reactive power capacity, a multi-timescale coordinated method is adopted between discrete compensation equipment, static var generator (SVG) and wind turbines considering different timescales of compensation equipment. In the reactive power distribution layer, a new wind turbine reactive power distributed strategy is adjusted considering forecasting trend of each wind turbine. The wind turbines with adjustable capability are selected according to dynamic filter coefficient considering reactive power forecasting and wind speed fluctuation to track reactive power demand. Engineering example proves that the proposed strategy improves the ability of supporting voltage and reduces the transmission losses of wind farm effectively. This work is supported by State Grid Corporation of China (No. DKYKJ2012]001-1).