Integrated Dispatch of Cascade Hydropower Stations and Hybrid Pumped Storage under Different Water Inflow Conditions

In response to the challenge of insufficient flexibility in power systems with a high proportion of renewable energy integration, this paper proposes an integrated dispatch model for cascade hydropower stations that includes a hybrid pumped storage power station. Through different water inflow conditions, considering unit characteristics and market pricing mechanisms, the model aims to maximize economic benefits by exploring the collaborative operation strategies of the units in cascade hydropower stations under different water inflow conditions, specifically during flood and dry periods. The study shows that during the flood period, when water resources are abundant, the pumped storage units in the hybrid pumped storage power station are dominated by the power generation mode, generating high power output and revenue while effectively absorbing surplus water energy. During the dry period, when water inflow is limited, the operation strategy shifts to a low-price energy storage and high-price power generation mode, with the number of pumping periods significantly increased and surpassing the power generation periods. This strategy takes advantage of arbitrage opportunities through peak-valley price differences to mitigate the revenue fluctuations caused by the reduced output of conventional units. This research aims to provide references for the upgrading of existing hydropower stations and the optimization of flexibility resources in the new power system, helping the evolution of the new power system towards a safer, more stable, and flexible direction.