分散式风电场不同时间等级的多目标无功优化控制

针对具有一定动态无功调节能力的双馈式风力发电机组构成的分散式风电场,为解决其经济稳定运行,提出一种包含风功率预测的不同时间尺度多目标无功优化控制方法。考虑风速变化相关性分组-单机预测风电机组无功输出情况,通过风电机组和SVC共同补偿电网无功需求;根据风电预测无功功率信息,采用多目标无功控制快速有效调节其输出功率以跟踪无功补偿指令。为减少风电场内设备动作次数,选取不同时间级的控制,目标为分钟级无功控制以有功网损最小为优化目标,秒级的无功控制以电压偏差最小、电压稳定裕度最大、短时闪变最小为综合优化目标,毫秒级的无功控制以机组变流器的瞬间最大无功支撑能力为优化目标进行无功分配。工程算例证明所提策略有效的降低网损、提高电压支撑能力并保证电网正常的运行。

Multi-timescale multi-objective reactive power optimization of dispersed wind farm

For distributed wind farm consisting of DFIG with dynamic reactive power regulation,in order to achieve economic and stable operation, a multi-objective reactive power optimization based on wind power forecasting was proposed. Considering the change of the wind speed to predict the reactive power output based on the correlation grouping-single unit. The reactive power demand of the power network was com-pensated by wind turbine and SVC. According to the wind power forecasting, the multi-timescale multi-objective reactive power optimization wind turbines were adopted considering reactive power forecasting and wind speed fluctuation to track reactive power demand. Choosing different time level control objec-tives for reducing the numbers of equipment movements, minute grade optimization target is minimum ac-tive power loss, seconds grade optimization target are maximum voltage stability margin and minimum short flicker, millisecond grade optimization target is maximum reactive power support capability. Engi-neering example proves that the proposed strategy reduces the transmission losses of wind farm and im-proves the ability of supporting voltage effectively.