考虑风电机组频率保护的送端电网有序高频切机策略

对于可再生能源占比较高且功率通过多回高压直流大量外送的送端电网,高压直流闭锁将引发高频问题,高频切机是抑制送端电网频率升高的重要控制措施.在考虑风电机组高频保护和直流闭锁后线路有功功率变化的基础上,提出了一种高频切机方案整定方法,并将其分解为首轮单次切机总量子模型和分轮次切机量优化整定子模型.综合利用线性插值法和摄动法求解各轮次切机量,并结合二元表进行灵敏度分析,优化高频切机方案.通过中国省级电网算例验证了所提高频切机方案的有效性,并校核了所提方案在不同运行方式下的适应性.

Orderly Over-frequency Generator Tripping Strategy for Sending-end Power Grid Considering Wind Turbine Frequency Protection

For the sending-end power grid where renewable energy accounts for a relatively high proportion and a large amount of power is sent out through multiple high-voltage direct current (HVDC) lines, HVDC blocking will cause over-frequency problems. Over-frequency generator tripping is an important control measure to restrain the frequency increase of the sending-end power grid. A setting method for the over-frequency generator tripping scheme is proposed based on considering the over-frequency protection of wind turbines and the active power change of transmission lines when HVDC blocking occurs. It is decomposed into the total generator tripping quantity submodel of the first round and the optimized setting submodel of generator tripping quantity of each basic round. The linear interpolation method and the perturbation method are used comprehensively to solve the generator tripping quantity of each round, and combined with the two-element table, the sensitivity is analyzed. Thus the over-frequency generator tripping scheme is optimized. The effectiveness of the proposed over-frequency generator tripping scheme is verified by an example of a provincial power grid in China and the adaptability of the proposed scheme is checked in different operation modes.