Study On The Theory And Application Of The Water-Source Pumping Station Optimal Operation Of South-to-North Eastern Route Water Diversion Project

In order to relieve the urgency of water resources shortage and the uneven distribution in time and space, inter-basin water diversion has become an important measure of water resources optimal allocation. Therefore, according to the latest achievements of modern decision theory and the actual situation of project management decision, developing inter-basin water diversion pumping station optimization operation research and putting forward advanced and practical method and theory have great significance on inter-basin water diversion project optimization operation in complicated environment. Selected Jiangdu Pumping Station that is the source of the eastern route of the South-to-North Water Diversion Project as an example, on the basis of the existing instation optimization theory, the paper develops comparision and discussion among different optimization calculation methods, especially expounds the mathematical models and solving methods and optimization result analysis of blade-adjusting regulation optimization and variable speed optimization and blade-adjusting regulation combined with variable speed optimization of parallel pumping stations, also preliminarily propsoes modeling and solving thoughts of cascade pumping stations, and the research has great academic and practical significance on the economic operation of inter-basin water diversion project and the development of optimal regulation decision support system. The main content and results include the following aspects:(1) Literature retrieval and review:based on reviewing lots of literature at home and abroad, summarizing practical significance and progress and existing problems of inter-basin water diversion pumping stations optimization operation research, the optimization theory system and research technical route of the parallel pumping stations in the eastern route of the South-to-North Water Diversion Project have been proposed.(2) Optimization model constructing and processing:according to the inter-station optimization problem, considering tide levels of Yangtze River and time-sharing electricity prices and so on, with the total pumping flow and rated power etc as constraints, with the minimum of electricity consumption cost as objective function, the variable condition optimization operation mathematical model of parallel pumping stations has been constructed, to determine the optimal combination scheme of operational pumps number and blade angles and speeds in different periods of each pumping station.Aiming at the complexity of optimization inter-pumping stations and grades, the handle technique of generalize system and recombine units has been proposed before model construction. According to the different types of the single station of parallel pumping stations and cascade pumping stations, the pump units have been recombined to form new parallel unit groups, the recombination can simply model construction and programming calculation, and can enhance the practicality of the rusults. (3) Optimization methods comparison and selection:for the in-station single decision variable nonlinear optimization, dynamic program method and enumeration method have been compared and analysised; for the in-station double decision variables nonlinear optimization, experimental optimization method and successive approximation method have been compared and analysised; for the multiple decision variables complex nonlinear system optimization of parallel pumping stations, large-scale system decomposition-amalgamation method and decomposition-coordination method have been compared and analysised. The above comparison and analysis not only verifies the reliability of the optimization results, but also analyses the discrepancy of differenent methods and enriches the calculation methods choice of parallel pumping stations.(4) Optimization calculation methods of parallel pumping stations:for the multiple decision variables complex nonlinear system optimization of parallel pumping stations, combining with the project example of parallel pumping stations optimization in Jiangdu Pumping Station, the paper adopts the large-scale system decomposition-amalgamation method to realize the water dispatching of pumping stations optimization operation, and uses the large-scale system decomposition-coordination method to verify the result, and enriches the optimized regulation theroy of such complex pumping stations system. As to the large-scale system decomposition-amalgamation method, firstly, subsystems of the decomposed layer adopt experimental optimization method or successive approximation method based on dynamic programming to search for the functional relationship between interrelated variables and subsystems targets, and subsystems interrelated equations can be obtained through regression analysis; then the aggregation model is constructed based on interrelated equations, and optimal solution is obtained; finally, through feedback of interrelated variables to every subsystem, the operational operation modes of every pumping station in different periods are determined.As to the large-scale system decomposition-coordination method, selected spatial subsystems as stages of the coordination layer, with water distribution coefficient of each stage as decision variable, with pumping flow as stage variable, the paper gives dynamic programming method to coordinate water quantity of subsystems collectively; each subsystem optimization of the coordination layer adopts the same method mentioned above.(5) Calculation process and optimization programming:according to the application of large-scale system decomposition-amalgamation method in parallel pumping stations optimization, and the regression analysis of the relationship between interrelated variable and subsystem target, in the optimization programming process of the aggregation model, we find a new recognition factor of water dispatching stop or procedure convergence, and it has been proved in theory. The recognition factor can adjust the direction of water dispatching in time and improve procedure convergence speed.At the same time, based on the software platform of Compaq Visual Fortran Version 6.5, the programming calculation of variable condition optimization operation modes and different calculation methods of parallel pumping stations has been realized, and it provides a feasible way to develop the decision support system of cascade pumping stations optimization operation of inter-basin water diversion project.(6) Results of optimization calculation:a) Based on 45 combination schemes of different-type pumps in different daily-average heads and operation loads in Jiangdu Pumping Station, both considering peak-valley electricity prices and not, the paper puts forward optimization results of blade-adjusting operation and variable speed operation of single pump unit, and analyzes the optimization effect of different-type pumps, and compares the effect of optimization operation and conventional operation(fixed blade setting angle and constant speed). b)In different daily-average heads and operation loads, both considering peak-valley electricity prices and not, the paper gives optimization results of blade-adjusting operation and variable speed operation of parallel pumping stations, and compares optimization operation with conventional operation. c)Under the same operation condition, the paper compares blade-adjusting optimization with variable speed optimization and combined optimization of parallel pumping stations. The above optimization calculation results and corresponding comparison enrich the optimization theroy of pumping stations, and offer reference for renovation and economy operation of large or medium type pumping stations considering peak-valley electricity prices and variable tide levels in Yangtze River.(7) Optimization of serial grades:based on the optimization modeling and solving of parallel pumping stations, optimization mathematical models of serial and serial-and-parallel pumping stations are presented, and the basic solving method has been preliminarily propsoed. The study has laid the foundation of realizing cascade pumping stations optimization, and of instation and inter-station and inter-grade pumping stations union optimization operation research of inter-basin water diversion project.