Growing DC feed-in scale outside East China has caused gradual decrease of frequency stability supporting charac-teristic in East China power grid.In allusion to two cases of DC block accidents in East China in 2016,this paper aims to de-velop simulation on frequency stability characteristics of receiving power grids.By adjusting primary frequency modulation characteristics of generators,it reappears frequency response process of the system after UHVDC block.Then,it carries out simulation on frequency stability after DC block of the maximum single circuit and double circuit under low-load operation mode.Simulation results indicate the primary frequency modulation abilities of current power grids are insufficient which may cause low-frequency load shedding risks after DC block.Thus,East China power grid has developed construction of fre-quency emergency coordination and control system and by system simulation,corresponding control measures are proved to be effective.Relevant research methods and conclusions have been used for simulating analysis on East China frequency and formulating accident plans so as to improve risk defense ability after DC block.%随着区外直流馈入规模不断增加,华东受端电网频率稳定支撑特性逐渐下降.针对2016年华东电网两起实际直流闭锁事故,开展受端电网频率稳定特性仿真,通过调节全网发电机一次调频特性,再现特高压直流闭锁后系统频率响应过程.在此基础上,开展汛期低谷方式下华东最大单回及两回直流闭锁后频率稳定仿真.仿真结果表明,当前电网一次调频能力不足,直流闭锁后存在低频减载动作风险.针对上述问题,华东电网已经开展频率紧急协调控制系统建设工作,通过系统仿真进一步验证相关控制措施的有效性.相关研究方法和结论已应用于华东电网频率仿真分析和事故预案制订,以提高直流闭锁后的风险抵御能力.
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