Study On Optimal Operation Of Water Resources In "Two Reservoirs And Two Stations" System In Southern China Based On Orthogonal Test

The total amount of water resources in South China is rich,but the temporal and spatial distribution of precipitation is uneven,and the problem of seasonal water shortage is serious.Therefore,when it is impossible to add new water conservancy facilities to provide additional water,we should give full play to the joint dispatching role of reservoirs and pumping stations,optimize water resources dispatching management,provide water resources utilization efficiency,and alleviate the water shortage problem in the water receiving area of the irrigation area.Taking the water resources dispatching engineering system composed of two annual regulation reservoirs and two replenishment pumping stations as the research object,considering the relatively abundant water resources in southern China,this paper proposes a complex nonlinear mathematical model for the optimal dispatching of water resources in the"two reservoirs two stations" system under the condition of sufficient irrigation,which takes the minimum sum of squares of the difference between supply and demand of water in the receiving area where the annual regulation reservoir and replenishment pumping station system are located as the objective function,The water resources operation of the system takes the month as the stage,the water supply volume of each stage of the two reservoirs as the decision variable,and considers the constraints of the total annual water supply volume of the reservoir and the makeup pump station system,the constraints of the reservoir operation criteria,as well as the water lifting capacity of the makeup pump station,the total annual allowable water lifting volume,the reservoir capacity and the makeup water volume of the pump station as the constraints.According to the characteristics of the model,if the water resources dispatching system composed of two annual regulation reservoirs and two reservoir replenishment pump stations is decomposed into two relatively independent subsystems（one is the single reservoir water resources optimal dispatching,and the other is the single reservoir single station water resources optimal dispatching model）,the coordination variable of the large-scale system is to connect the water lifting capacity of each period of the water lifting pump station between the two reservoirs.Therefore,this paper proposes a large-scale system test combination algorithm of large-scale system coordinated variable test optimization and two subsystems（single reservoir,single station and single reservoir）dynamic programming optimization,that is,the orthogonal test optimization method is used to determine the water replenishment of each period of the intermediate water transfer pump station.On this basis,the subsystem model can be solved by one-dimensional dynamic programming,and then the subsystems are aggregated to obtain the minimum water shortage in the water receiving area of the whole system The corresponding optimal water supply and disposal processes of the reservoir in each period,as well as the optimal water replenishment process of the reservoir make-up pump station.This method can be used as a reference for solving mathematical models with similar structural characteristics.In this paper,taking the two reservoirs of "Shanhu reservoir and niqiao reservoir" and the two stations of "Xiaozhuang and Huzhuang water pumping stations" in Shanhu niqiao irrigation area of Liuhe District in Nanjing as the research objects,the water frequency p=75%and p=95%are taken as examples.Using the above model solving method,the water resources scheduling in this area is calculated and optimized,and the results are compared with the conventional scheduling results.The optimization results show that when the inflow frequency is p=75%,there is 980 thousand m3 in the irrigation area under the conventional operation water shortage and 310 thousand m3 waste water,;After optimized dispatching,the water shortage is reduced by 310 thousand m3（from 980 thousand m3 reduced to 670 thousand m3,decreased by 31.6%）,and the water supplement volume of Huzhuang station increased from 5.92 million m3 reduced to 5.34 million m3,decreased by 9.8%;After optimization,the reservoir in the irrigation area has no abandoned water.When the water inflow frequency is p=95%,the irrigation area has 2.66 million m3 of conventional regulation due to the small amount of water inflow 3 After optimized dispatching,there is no change in water shortage,and the water replenishment of Huzhuang station is increased from 9.35 million m3 reduced to 8.55 million m3,reduce by 8.6%,and there is no waste water in the irrigation area.By comparing with the conventional dispatching,it is proved that the optimal dispatching can optimize the distribution mode of water resources in the reservoir station system,achieve the purpose of making up for the poor with the abundant,increase the effective water supply,reduce the water shortage,reduce the waste water,and ensure the water demand in the water area as much as possible,and the optimal dispatching reduces the make-up water volume of the make-up pump station,which is equivalent to reducing the operation cost of the pump station and indirectly improving the utilization efficiency of water resources.Finally,this paper uses Visual Basic software to develop the water resources optimization configuration module of the "two reservoirs and two stations" system,and input the corresponding reservoir parameters,incoming water demand and pre replenishment scheme of the water transfer pump station to obtain the optimal water supply scheme of the reservoir and the replenishment scheme of the pump station.It is suitable for irrigation areas with similar reservoir water supply systems and can be used as a reference for irrigation area management and operation.