考虑风电主动参与频率控制的电力系统运行可靠性评估

Operational Reliability Assessment of Power System Considering Active Participation of Wind Power in Frequency Control

近年来,通过采用合理的控制策略,双馈感应式风力发电机组已广泛参与系统的频率调节过程。因此,风电作为一种日益重要的能源,有望在现代电力系统中兼具重要的发电和频率调节任务。考虑到风力资源的多变性,风力发电具有固有的不确定性,大规模风电并网会给电力系统可靠性和频率安全带来冲击。研究了高比例风电电力系统可靠性和频率的综合评估问题,首先,对计及双馈风机虚拟惯性响应的系统频率调节过程建模,求解系统在供需波动和设备故障下频率偏差的解析表达式;其次建立了发电机频率敏感的可靠性模型,旨在分析系统可靠性和频率偏差间的耦合关系;最后提出了多时间尺度分析框架用于计算系统可靠性和频率综合指标。结果显示,提出的框架在可靠性评估中综合考虑了频率调节过程及频率变化对可靠性参数的影响,可为高比例风电电力系统运行可靠性研究提供一定指导。

Recently, doubly-fed induction generator-based wind turbines(DFIG-WTs) have been widely involved in the system frequency regulation process by adopting reasonable control strategies. Thus, wind power, as an ever-increasingly important energy source, is expected to play a significant role in both power generation and frequency regulation in modern power systems. Considering the variability of wind resources, wind power generation has inherent uncertainties, and the integration of large-scale wind power into the grid will impact the reliability and frequency security of the power system. This paper investigates the integrated assessment of reliability and frequency of power systems with a high penetration level of wind power. Firstly, the system frequency regulation process considering the virtual inertia response of DFIG-WTs is modeled. The analytical expression of system frequency deviation under supply and demand fluctuations and equipment failures is solved. Secondly, a frequency-sensitive reliability model of the generators is established to analyze the coupling relationship between system reliability and frequency deviation. Finally, a multi-time scale analytical framework is proposed to calculate the integrated reliability and frequency indices. The simulation results show that it is necessary to consider the influence of the frequency adjustment process and frequency deviation on the generators’ reliability parameters when evaluating the reliability of a high-proportion wind power system.