| With the increasing demand for hydropower in China,it is very necessary to develop optimal operation schemes of reservoirs to use hydropower resources rationally.However,while meeting the economic needs of the hydropower station,it is inevitable to face a series of safety risks and challenges,especially the navigation of ships.There is a close relationship between power generation and the hydraulic process of the near-dam channel.During the operation of the reservoir,due to the needs of large discharge,peak regulation and frequency modulation,there is complex hydraulic phenomena in the channel,such as rapid rise and fall of the water level,and large water flow,which seriously affect the navigation of the ships.Therefore,to explore the impact of reservoir economic operation on ship navigation,and to explore the power generation-navigation joint safety operation scheme,has become an urgent theoretical and practical subject to be solved in China’s reservoir operation.Therefore,the Xiangjiaba reservoir which has both power generation and navigation requirements,is selected as the study case in this paper.A two-dimensional model of the upstream and downstream channels of the reservoir is established,and an evaluation and quantification method of navigation capacity is proposed.Besides,a short-term power generation-navigation multi-objective optimal operation model is established,and the multi-objective optimization intelligent algorithm is used to solve model.The purpose of this paper is to provide technical support and decision support for multi-objective optimal operation of reservoirs.The main research contents and results of this paper are as follows:(1)Because the existing evaluation and quantification methods of navigation capacity only consider the hydraulic factors such as water level and flow,but the influence of flow velocity is ignored.Based on the two-dimensional hydrodynamic model of the channel,a navigation capacity evaluation method is proposed,and the software MIKE21 is used to build the refined hydrodynamic model,in order to explore the impact of reservoir operation on the water flow regime,analyze the influence of the flow field(longitudinal velocity,transverse velocity and reflux velocity)on the navigation capacity.It will lay the foundation for solving the problem of joint optimization of reservoir considering power generation and navigation.(2)According to the hydraulic coupling response relationship of power generation and navigation,a multi-objective optimal operation model of reservoir considering power generation and downstream navigation is established with the objective of maximum total power generation and maximum navigation capacity,and then a solution framework of the model is established.In addition,several comparative models to verify the rationality and effectiveness of the model are established.On the other hand,based on the navigation capacity evaluation method considering flow velocity,another navigation capacity evaluation method considering the combined influence of flow velocity and water level is proposed.According to this method,a multi-objective optimal operation model of reservoir considering power generation,upstream and downstream navigation is established.Finally,a multi-objective intelligent algorithm is used to solve the model.(3)The proposed method and optimal model is applied to the case study of Xiangjiaba Reservoir,and the coordination and restriction relationship between power generation benefit and navigation capacity is analyzed.By analyzing the control process of water level in several typical operation schemes,the cause and mechanism of this complex relationship are obtained,and the rationality of the reservoir output process is verified.It will provide useful suggestions for actual operation decision of reservoir and safe access to upstream and downstream channels of ships. |
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