Multi-Timescale Joint Optimal Dispatch Model Considering Environmental Flow Requirements for a Dewatered River Channel: Case Study of Jinping Cascade Hydropower Stations

Abstract

In this study, the authors developed a multi-timescale optimal dispatch model to balance both the environmental flow requirement of the downstream dewatered river channel and the power output of the cascade hydropower stations. The operation characteristics of turbine units, reservoir regulation capacity, inseparable hydraulic connections, and the mass balance equation of the cascade reservoirs and water head loss characteristics of the tunnels have been considered to constrain the model. The daily average flow solution set of the monthly timescale model was converted to a daily flow process solution set of the daily timescale model to decouple the two-hierarchy model. The application of the model with two hierarchies shows that the model can reduce the dimension of the decision variables and derive optimal decisions more quickly to simultaneously meet the two objectives. Considering the environmental flow demand of the dewatered river channel, this study puts forward an operation strategy for Jinping cascade hydropower stations. The research results can provide decision support for other cascade reservoirs that have a dewatered river channel.