大规模风电经LCC-HVDC送出的送端电网频率协同控制策略

针对大规模风电经电网换相型高压直流(LCC-HVDC)送出的送端电网所面临的严峻高频问题，充分挖掘风电潜在调频能力，提出一种风电与直流频率限制器(FLC)参与送端电网调频的协同控制策略。分析直流FLC参与送端电网调频的响应特性，刻画送端电网频率与风电机组功率的下垂关系，设计风电机组变转速与变桨距角相结合的一次调频控制方法。建立包括常规机组一次调频、风电机组下垂控制和直流FLC的频率响应综合模型，结合电网的频率稳定要求，采用灵敏度方法整定风电机组与直流FLC的调频参数，设计风电与直流FLC共同参与的频率协同控制策略。算例仿真结果表明：所提频率协同控制策略可有效降低高频切机、直流过载运行风险，提高送端电网的频率稳定性。

Frequency cooperative control strategy of sending-end power grid with large-scale wind power sent out by LCC-HVDC

In view of the severe high-frequency problems faced by the sending-end power grid with large-scale wind power sent out by the line commutated converter based high voltage direct current(LCC-HVDC),and fully digging the potential frequency regulation capability of wind power, a cooperative control strategy of wind power and DC frequency limit controller(FLC) participating in the frequency regulation is proposed. The response characteristics of DC FLC participating in the sending-end power grid frequency regulation is explored, the droop relations between the frequency of the sending-end power grid and the power of wind turbines is described, a primary frequency regulation control method combining variable speed and variable pitch angle of wind turbines is designed. A comprehensive frequency response model including primary frequency regulation of conventional turbines, droop control of wind turbines and DC FLC is proposed. Combined with the frequency stability requirements of the power grid, a sensitivity analysis is carried out to investigate the frequency regulation parameters of wind power and DC FLC, and the frequency coordination control strategy involving wind power and DC FLC is designed. The simulative results show that the proposed frequency cooperative control strategy can reduce the risk of high frequency generator tripping and DC overload operation, and improve the sending-end power grid frequency stability.