基于估测惯量计算的低频减载方法

新能源发电接入系统的控制方式的不同会给系统的惯量带来不同的影响，研究了基于估测惯量系统功率缺额实时计算方法。首先分析了现有低频减载装置计算系统功率缺额算法的不足。针对这些不足，研究了电压偏移对系统有功缺额的影响，并给出了量化算法；根据扰动后负荷的响应信息，提出了实时辨识系统惯量的方法，由此得到基于估测惯量的系统功率缺额实时计算方法，进而得到最优的自适应切负荷方案。在IEEE 39节点系统下进行孤岛系统的仿真，验证了研究得出的电压偏移对系统有功缺额的影响，以及系统惯量的实时辨识、系统功率缺额实时计算的准确性和有效性。与传统的分轮次动作的低频减载方案相比，所提方案的负荷减载量以及动态频率偏移相对更小，频率恢复稳定能力更强。

Under-frequency load shedding scheme based on estimated inertia

Different control methods for new energy power generation access to systems will bring different influences to the inertia of system. The real-time calculation method to calculate power shortage based on estimated inertia is proposed. Firstly, the shortcomings of the existing under-frequency load shedding equipment for calculating power shortage are analyzed. In view of these shortcomings, the influence of voltage deviation on active power balance is studied, and the quantization algorithm is proposed. According to the response information of load after disturbance, a real-time method to recognize system inertia is proposed. Then, the real-time calculation method to calculate power shortage based on estimated inertia is proposed. The simulative results of islanding system in IEEE 39-bus system verify the influence of the voltage offset on the calculation of power shortage, and the veracity and validity of recognizing system inertia and calculating power shortage in real-time. Compared with the traditional round-by-round load shedding schemes, the proposed scheme has relatively small amount of load shedding and dynamic frequency offset and stronger ability of frequency recovery.