| China has been deeply disturbed by floods since ancient times.Floods in the plains of the middle and lower reaches of the Yangtze River are the most frequent and serious,and it has always been the worry of our nation.The disasters caused by floods have caused huge losses to the lives and property.In addition,with the development of economy and society,the demand for energy is increasing year by year.As a kind of clean energy,hydropower,occupies an important position in the energy supply of my country’s national economic development.Reservoirs realize the redistribution of water resources by blocking runoff and using hydropower to generate electricity,which can achieve benefits and harm elimination.They usually shoulder the needs of multiple tasks,such as flood control,power generation,shipping and water supply.Among them,the significance of flood prevention and power generation are especially prominent.At the present stage,the large-scale cascade reservoirs built in my country have the characteristics of complex system connection,large installed capacity and multiple operation constraints,which makes the complex phenomena and technical problems that faced in the optimization of system operation and management become increasingly prominent.How to optimize the operation and management technology through the joint dispatch of reservoir groups and improve the benefits of cascade reservoirs for flood control and power generation has always been the focus and difficulty in the field of water resources research.This paper aims at optimizing the joint dispatch method of reservoir groups and mining the overall benefit potential of the reservoir group.By introducing system modeling theory and intelligent optimization theory,the key technologies of cascade reservoir joint flood control compensation optimal operation and power generation optimal operation are carried out in-depth research.The main research contents and innovation points include:(1)Aiming at the complex optimization problems of high-dimensional,nonlinear,coupling and strong constraints and the shortcomings of existing differential evolution algorithms,a parameter adaptive differential evolution algorithm based on linear decreasing population combined with successful evolution history was proposed.An improved mutation strategy "Current to pbest/2-rand" based on "current to pbest / 1" was proposed,which expands the search range of optimization.And a strategy to prevent individuals from repeating evolution failures was proposed,which can avoid the algorithm from falling into local optimality.The adaptive parameter allocation method is introduced and improved.The improved differential evolution algorithm was used to simulate low-dimensional and high-dimensional optimization problems.The results show that the proposed method has the characteristics of stable convergence and efficient solution,compared with other differential evolution algorithms.(2)Aiming at solving the optimization problem of the medium and long-term power generation plan of the giant cascade reservoir group,the medium and long-term power generation optimization model of the giant cascade reservoir group was established,and the model constraint processing was improved.The ε-constraint method was introduced in the process of dealing with the discharge,water level and electricity constraint problems in the operation of cascade reservoir.The improved differential evolution algorithm proposed in this paper was utilized for the optimization of medium and long-term power generation of giant cascade reservoirs.The results of application examples show that the optimized scheme obtained by using the proposed power generation optimal operation model and solution method can obtain more power generation benefits in wet,flat and dry years,and improve the overall power generation benefits of cascade power stations.(3)According to the characteristics of the Three Gorges Reservoir,the dynamic reservoir capacity flood regulation calculation method is adopted and the concept of the reservoir flow is defined by the Three Gorges reservoir outflow and tank storage changes to establish the Three Gorges reservoir flood regulation calculation model.The typical models of river flood evolution were sorted out.And based on the characteristics of the research object and the suitability of the model,the types and solutions of the flood evolution models of the downstream river and upstream reservoir of the Three Gorges Reservoir were selected and solved.Targeted improvements have been made in river division,tributaries inflow and interval flood in the model.Example verification proves that the model shows high simulation accuracy in the flood evolution simulations of the downstream and upstream reservoirs of the Three Gorges Reservoir.Based on the single model,a multi-model oriented multi-region,long-distance reservoir flood control operation simulation system was constructed,and it can provide reliable technical support for flood control simulation and scheduling scheme selection.(4)Using a long series of historical data,in-depth analysis of the time of flood occurrence,flood type,flood magnitude and combination encounter law in the upper and lower reaches of the Yangtze River was carried out.The typical flood year was selected according to the flood characteristics,and the overall design flood was calculated by the method of flood volume magnification,which was selected as the boundary condition of the optimal flood control operation of the reservoir.The upstream reservoir group cooperates with the Three Gorges flood control operation method and the Three Gorges Reservoir’s flood control compensation operation optimization method for Chenglingji was proposed.The flood control situation in Chenglingji area was analyzed,and the refined operation method based on risk transfer control water level and the scheme of flood compensation operation for Chenglingji were proposed.The Three Gorges Reservoir flood control compensation operation plan was simulated,analyzed and the impact was judged.Based on the coordination of upstream and downstream flood control risk,the appropriate range of the Three Gorges Reservoir’s flood control compensation control water level for Chenglingji and the corresponding storage capacity subdivision methods and corresponding risk control measures were proposed.The simulation of a typical flood in 1954 shows that the proposed optimization operation method that the Jinsha River cascade cooperating with the Three Gorges Reservoir to carry out flood control compensation dispatch for Chenglingji area can significantly reduce the excess flood volume in the middle and lower reaches of Chenglingji,Wuhan and Hukou areas,and further improve the Three Gorges Reservoir’s flood control compensation capabilities for the downstream areas have been improved. |
PDF Full Text Request