| The South-to-North Water Diversion Project is a great action for solving the serious shortage problem of water resources in northern China. Also it is an important construction project of water infrastructure related to the economic and social sustainable development of China. Because of the long water conveyance line, high lift, large flow, and involving multiple fields such as natural science and social science, the South-to-North Water Diversion Project is a high dimensional complex system with complex structures, various forms, multi-water resources, multi-areas and multi-objects. There are the Eastern Route, Middle Route and Western Route included in the South-to-North Water Diversion Project, in which the Eastern Route Project is an important part of general pattern of water resources in China. Raising water from downstream of yangtze river, the eastern route project transports the water resources northward through each stage of pumping stations for eastern Huang-Huai-Hai Plain with the destination of Tianjin City. The project implementation will improve the economic development and social progress of local areas, effectively restrain the continuous deterioration situation of ecological environment, by which to improve people’s living quality. In addition, the dredging and regulation of rivers and lakes will greatly improve the conditions of flood prevention, shipping and ecological environment. Therefore, it has a significant comprehensive benefit. There are13stages of pumping stations with total installed capacity of392.59MW consisted in the first phase project of Eastern Route of South-to-North Water Diversion Project. Because of the yearly running time of5000-6000h, the annual operation cost reaches0.98-1.18billion yuan. It is important to take optimal and high efficient operation for reducing water transfer cost and healthy operation of project as a result of long time operation and large installed capacity. Therefore, by means of adopting the latest achievement of modern decision theories and combining with actual situation of project decision management, it is necessary for optimal operation study of interbasin water diversion system to propose advanced and practical theories and methods of system optimization, which has an important significance to improve the decision quality of optimal operation under complicated environment (such as the precision of decision achievements, effectiveness and operation cost).Currently, the relevant studies on optimal operations of pumping stations systems mostly take a lot of simplifications into the optimal models and adopt few complex system theories, which could not obtain further energy saving and lower operation cost carried out by working-condition adjusted function of large-scale pump units. This paper carried out systematic researchs on single pumping station (No.4Huai’an pumping station, No.3Huaiyin pumping station), parallel pumping stations (No.1,2,4Huai’an pumping stations, No.1,3Huaiyin pumping stations), multistage pumping stations (No1,2,4Huai’an～No.1,3Huaiyin pumping stations) based on the proposing decomposition-dynamic programming aggregation method, and following aspects were developed:(1) Considering peak-valley electricity prices, a series of optimal operation theories were systematically proposed after the comprehensive studies on single pumping station with multiple units, parallel pumping stations and multistage pumping stations being carried out.①ecomposition-dynamic programming aggregation method for large-scale system was put forward to solve the mathematical model of optimal daily operation for single pumping station with adjustable-blade. After taking No.4Huai’an pumping station as a study case, a series of optimal daily operation schemes were obtained. The comparison and analysis were taken out according to the optimal achievements obtained by decomposition-dynamic programming aggregation method and dynamic programming with successive approximation. This method could solve the optimal operation issues for single pump station with different unit types or the same type with performance differences.②ccording to the optimal mathematical model of daily variable speed operation with VFD, the decomposition-dynamic programming aggregation method was also applied to solve the model and to obtain a series of optimal daily operation schemes after No.3HuaiYin pumping station was used as a study case, in which the variable efficiency of frequency conversion device with the pump speed changing was under consideration.③As for optimal daily operation issues for parallel pumping stations with the same and different working-condition adjective modes, two stages decomposition-dynamic programming aggregation method was proposed to solve the mathematical model of optimal daily operation for parallel pumping stations. With the consideration of peak-valley electricity prices, a series of optimal daily operation schemes were obtained after taking No.1,2,4Huai’an parallel pumping stations(optimal operation with adjustable-blade) and No.1,3Huaiyin parallel pumping stations(optimal operation with adjustable-blade for No.1and optimal variable speed operation with VFD for No.3) as study cases. This method could solve the optimal operation issues for parallel stations with various operation modes, time period divisions and average daily heads of each station.④According to optimal operation issues for multistage pumping stations, with the combination of mathematical model of optimal operation for parallel pumping stations with one-dimensional numerical simulation of unsteady channel flow in water supply channel of interstages(the relationship between flow and head), the comprehensive optimization method with the combination of water pumping head in two stages pumping stations and optimal operation of pumping stations were proposed. A series of preliminary optimal daily operation schemes were obtained after taking No,1,2,4Huai’an parallel pumping stations-No.1,3Huaiyin parallel pumping stations as a study case.⑤Based on mathematical model solution of daily optimal operation for single pump unit, with the peak-valley electricity price considered, according to the optimal daily operation of single pump unit with adjustable-blade and operation with fixed blade angle and constant speed, the dynamic programming method and linear programming were carried out to study the optimal start-up time of pumping station influenced by tidal levels, by which the regular distribution of optimal start-up time in a month was obtained.(2) The obtained optimal operation schemes for single pumping station with adjustable-blade, single pumping station with variable speed, parallel pumping stations with the same or different working-condition adjective modes and multistage pumping stations could enrich and develop the inter-basin water transfer theories, and has a great application value for optimal operation of large-scale pumping stations in Eastern Route of South-to-North Water Diversion Project.(3) The proposed decomposition-dynamic programming aggregation method and two stages decomposition-dynamic programming aggregation method has a general guiding significance for complex nonlinear models such as optimal daily operation model of single pumping station and parallel pumping stations, which could enrich and develop large-scale system theory. |
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