Study On Optimal Compensative Operation Of Cascade Reservoirs Based On Load Distribution

With the installation of new turbines and hydropower plants, existing operation mode is difficult to achieve joint optimization operation. The formulation of operating rule curves for cascade reservoirs involves large amount of data and calculation. Recently, universal and scalable method for deriving operating rule curves for cascade reservoirs is rare. Solving ability of existing optimization method is limited, and the quality of solutions is difficult to ensure, which leads to difficult application, especially in solving complex large-scale system. Thus, it is necessary to study cascade hydropower optimization operation. The research results can not only satisfy the needs of actual operation and management for cascade reservoirs, but also make full use of hydropower resources, and provide good examples for optimal operation of other large-scale cascade reservoirs.In this paper, the Lancang River cascade reservoirs were used as case study. A simulation-based optimization method was proposed to optimize the operating rule curves. Besides, given ecological flow, a limited compensative operation model for cascade reservoirs was developed. The main work in this paper is as follows:(1) On the basis of load requirements issued by the grid and features of optimal operation for cascade reservoirs, the cascade nonstorage energy loss minimum model and cascade storage energy maximum model were proposed. Then, the discriminant coefficient method and direct load allocation algorithm were developed to solve the models, respectively. Finally, analysis on advantages and disadvantages of these two methods were carried out.(2) Considering the development and construction features of the Lancang River, a practical and effective model for deriving optimal operating rule curves for cascade reservoirs was proposed. And a simulation-based optimization method was used to solve the model. Twelve hydropower plants of Lancang River were taken as examples. Simulation results shown that the proposed method was reasonable and efficient and could be applied to other cascade reservoirs as a reference method as well.(3) Given new problems and requirements emerged in the Lancang River project, a limited compensative operation model for cascade reservoirs considering ecological flow was developed. The model made adjustments on the previous optimal operation model for cascade reservoirs. The simulation results shown that the model was of great significance for ecosystem and sustainable development of the basin.Finally, the entire paper was concluded, and related problems for further study were given.