特高压直流输电系统发生直流闭锁故障时,受电端电网瞬间损失功率必须依靠区域内电厂调频来弥补,火电机组的作用尤为关键,现阶段火电厂多为高参数大容量机组,机组的蓄能非常有限,电网直流闭锁故障引发的大频差一次调频动作时,火电机组一次调频贡献电量受到机组蓄能的影响,不利于电网事故的快速恢复,还可能引起电网频率的振荡.以目前比较典型的600 MW等级火电机组为例,在皖电东送田集电厂进行大频差时一次调频和协调控制策略的相关试验.研究优化方向,采用了形式多样的新型控制策略,改善机组协调控制和一次调频性能,提高事故状态下火电机组对电网的贡献度.%When the DC blocking fault occurs in the UHVDC transmission system,the instantaneous power loss in the receiving power grid relies on the power plant primary frequency regulation in the region for compensation,and the thermal power unit plays a very important role.Presently,most thermal power units are of high capacity and high parameters with very limited energy storage capacity.In the large frequency-difference primary frequency regulation triggered by the DC blocking failure of the power grid,the power contribution of the thermal power unit is affected by the energy storage of the unit,which is not conducive to the rapid recovery of the power grid accident and may cause grid frequency oscillation.In this paper,the Tianji Power Plant of Sending Power from Anhui to the East Project is taken as an example of the typical 600 MW thermal power units to conduct the testings on primary frequency regulation of large-frequency difference and the optimization of related coordination control strategies.A variety of new control strategies are adopted to improve the unit coordinated control and the primary frequency performance so as to increase the contribution of thermal power units to the power grid during faults.
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