Study On Optimal Operation Of Cascade Hydropower Stations Considering Multi-basin Coupling

China has the most hydropower energy reserves in the world and hydropower energy mainly distributes in the western region especially in the southwest region(Yunnan Guizhou Sichuan Chongqing Tibet).The main hydropower energy bases are concentrated in some watersheds.Such as the upper reaches of the Yangtze River upper reaches of Yellow River the Jinsha River the Yalong River Lancang River Wujiang River Nanpan River Hongshui River and so on.According to the “three-step” strategy of hydropower development in China by 2050 the conventional hydropower installation will reach about 90% of the exploitable hydropower.The rapid development of hydropower industry in China has attracted worldwide attention.However with the large-scale development of hydropower cascade hydropower stations in the basin have faced unprecedented challenges in terms of system size control requirements and utilization of demand.In order to solve this problem the optimal operation of cascade hydropower stations with multi-basin coupling is studied in the paper.The research results are as follows:(1)Based on the methods of frequency statistics and factor analysis the hydrological conditions of runoff in the watershed are evaluated in detail.And the discrete type of division mode which the hydrological conditions of runoff in the basin are traditionally classified as extremely dry dry normal wet and extremely wet has become continuous division of the way.The first hydropower station in a basin is taked as an example the hydrological conditions are analyzed and evaluated based on the inflow runoff from 1956 to 2010.And the results of fine evaluation of runoff hydrological conditions are given.(2)The optimal operation model for short-term generation of cascade hydropower stations in the watershed is proposed.The model takes the maximization of total generation benefit of cascade hydropower stations as the objective function taking into account the water level,the flow,water balance,cascade hydraulic connection constraints and so on.Then the basic principle and solution steps of the model solving algorithm-the weight improved particle swarm optimization algorithm are introduced.Finally an example is calculated by taking the hybrid hydropower energy system of ten reservoirs.The feasibility of the improved particle swarm optimization algorithm in solving this kind of problem is verified.(3)A partition optimization method for solving the long-term optimal operation model of multi-basin cascade hydropower stations is proposed which based on the idea of large-scale system decomposition and coordination.According to this method The multi-basin cascade hydropower stations are divided into layers and zones.Then the weight improved particle swarm optimization algorithm is used to solve the problem.The proposed method is verified by an example of the cascade hydropower stations in NPJ-BPJ-HSH basin and good calculation results are obtained.