计及频率稳定的多直流异步外送电网切机容量优化

异步互联格局下，送端电网惯性大幅下降，因直流闭锁引发的高频问题较为严重，传统应对高频问题的稳控切机策略存在切机量不精确（过切或欠切）以及切机后系统转动惯量匮乏等风险。针对现有稳控切机方案的不适应性，提出一种计及系统频率稳定需求的多直流异步外送电网切机容量优化模型。模型中耦合大容量直流闭锁故障下各种频率指标约束、网络潮流约束、备用及切机量约束，考虑系统内各类型机组调节性能及位置的差异性，利用理想点法和优序图法得到各类型机组的切机惩罚因子，通过切机综合代价最小化目标确定大容量直流闭锁事故下送端电网的最优切机方案。以改进的IEEE RTS-79系统为例进行了算例分析，验证了所构建模型的有效性与频率适应性。

Generation Shedding Capacity Optimization of Sending-End Power Grids with Multi-DC Asynchronous Outfeeds Considering Frequency Stability

For the asynchronous interconnection system, the inertia of sending-end power grid drops sharply. Because of the severe high frequency problems caused by bipolar blocking of a HVDC transmission line, the traditional generation shedding strategy for dealing with the high frequency problems has some risks such as inaccurate shedding capacity (i.e. over- shedding or under-shedding) and lack of the rotational inertia after shedding. In order to solve the inadequacy of existing generation shedding schemes, we propose a generation shedding capacity optimization model for the sending-end grid with multi-DC asynchronous outfeeds considering the stability of system frequencies. The model comprehensively considers a variety of constraints, such as the frequency constraints, network power flow constraints, reserve constraints, and the constraints of generator-tripping capacity. By taking account of the adjustment performance and geographical distribution differences of various units in the sending-end grid, the TOPSIS method and the Superiority Chart are used to obtain the penalty factors of various units, and the optimal generation shedding scheme of the sending-end grid is determined for the bipolar blocking fault of a large-capacity HVDC transmission line with the goal to minimize the comprehensive cost of generator tripping. An improved IEEE RTS-79 test system is taken for case study, which has verified the effectiveness and the frequency adaptability of the proposed model.