1.Institute of Hydropower and Hydroinformatics, Dalian University of Technology, Dalian 116024, China;2.Three Gorges Cascade Dispatch and Communication Center, Yichang 443002, China;3.Kunming Power Exchange Center Co., Ltd., Kunming 650011, China

Due to the differences in operation conditions during dry and wet seasons, complex relations between water power and electric power, and comprehensive utilization demands such as flood control, ecology, navigation and so on, it is difficult to solve how to evaluate the defense capability of 10 GW-level large-scale cascade hydropower stations against long-period extreme fluctuations of renewable energy. First, the analytical characterization method of extreme fluctuations of renewable energy is proposed, and the extreme fluctuation events are mined from the historical data so that the characteristics of wind power-photovoltaic extreme fluctuations can be revealed. On this basis, a perturbation optimization evaluation model of defense capability of cascade hydropower plants against extreme fluctuations of renewable energy is established. The 0-1 mixed-integer linearization modeling technique is adopted to efficiently solve the mathematical model. Taking a river basin cascade hydropower stations station of a Southwest provincial power grid in China as an application case, the defense capability of cascade hydropower stations against extreme fluctuations of renewable energy and its sensitivity to the renewable energy installed capacity are analyzed, and the results can provide guidance for electric power and energy balance scheduling under extreme weather in power grid.