基于频率动态特性的电力系统频率失稳概率评估

提出一种电力系统频率失稳风险评估方法,该方法计及了旋转备用的频率动态特性,建立了低频减载作用下的频率稳定分析模型。基于非序贯蒙特卡洛仿真,计算分析了失稳概率、失稳频率、期望切负荷量和频率动态指标,实现了对频率稳定性的概率量化评估。探讨了旋转备用容量变化、低频切机容量变化对频率稳定性的影响,并计算了在多层负荷模型中计及和不计及不确定性两种情况下的频率稳定年度指标。IEEE RTS79系统算例分析表明所提方法能从概率角度全面深入评价电力系统的频率稳定性,可为低频减载配置方案的合理性和机-网的协调性提供一定参考依据。

Probabilistic Assessment for Frequency Instability of Power System Based on Frequency Dynamic Characteristic

An approach for frequency instability risk assessment of bulk power system is proposed in this paper.Based on the dynamic frequency characteristic of spinning reserve,the model of frequency stability analysis considering under frequency load shedding is presented.Utilizing the non-sequential Monte Carlo simulation,risk indices such as instability probability、instability frequency,expected load shedding and frequency dynamic indices are calculated for probabilistic quantitative evaluation of frequency instability.The impact of spinning reserve and generators tripping on frequency instability are discussed.Moreover,the annual risk indices including or excluding uncertainty for multi-level load model are analyzed.Simulation results of IEEE-RTS79 verify that the proposed method is a powerful tool which can provide valuable reference information for identification of frequency instability risk and optimizing of under frequency load shedding scheme.