Study On Optimal Operation Of Cascade Pumping Stations In Jingdian Project

There are serious problems of water shortage and unequal distribution of regional water resources in Northwest China.In order to realize the rational allocation of water resources and meet the water supply needs of life,production and ecology in arid and water shortage areas,several long-distance,inter basin water transfer high lift cascade pumping stations have been built in Northwest China.The cascade pumping station project generally has the characteristics of large installed capacity,long operation time and large energy consumption.In the actual operation,some pumping stations will also have the problems of low operation efficiency and high operation cost.During the operation of the cascade pumping station,affected by rainfall,water demand in irrigation area,pump station condition regulation and sediment concentration of the Yellow River,the water level and sediment concentration at all levels of the pumping station will increase The flow rate is always changing,which affects the overall operation efficiency of cascade pumping stations.Therefore,the scientific and reasonable optimization of the operation of the cascade pumping station can make the cascade pumping station system reach the dynamic balance state under different water level and flow conditions,which is of positive significance to improve the operation efficiency of the water conveyance system of the cascade pumping station and realize the economic operation.In this paper,the cascade pumping station system of Jingtaichuan electric power pumping project in Gansu Province(hereinafter referred to as Jingdian project)is taken as the research object.On the basis of field investigation and operation data collection,the key index parameters affecting the operation efficiency of the cascade pumping station system are explored,and the actual operation energy efficiency of Jingdian project is evaluated through scientific and reasonable mathematical model;Taking the water level of forebay,water lifting capacity and water demand balance of irrigation area of cascade pumping stations as constraints,combined with the application of variable frequency regulation,regulating and storage tank and other technologies,the optimal operation of cascade pumping station system is studied with the objective of minimizing the amount of waste water,power consumption and water shortage among cascade pumping stations,In order to provide some reference for the actual operation optimization of similar large-scale cascade pumping stations in China.The main contents of this paper are as follows:(1)On the basis of combining the water transmission and distribution mode of Jingdian cascade pumping station and the structural characteristics of the water delivery system,considering the actual conditions of imperfect monitoring equipment in the operation of the project,the scientific and reasonable operation efficiency evaluation model is adopted,and the actual operation data of the water delivery system of Jingdian cascade pumping station from 2013 to 2017 is selected as the research object to evaluate the actual operation efficiency of the pumping station,At the same time of quantifying the actual operation energy efficiency of the project,the application effect of optimized operation technology in Jingdian project is scientifically verified.(2)Through the analysis of the factors affecting the operation efficiency of the pump unit,the research on the high efficiency operation of a single pump unit is carried out.The high efficiency operation point of the pump unit is determined according to the parameters of each unit.Based on the consideration of the transmission efficiency and motor efficiency,the performance and efficiency of the pumping device are analyzed to determine the device efficiency under different flow and head conditions,It provides a theoretical basis for the study of the joint operation optimization of multiple units in pumping stations at all levels.(3)Taking the minimum amount of waste water,power consumption and water shortage among the cascade pumping stations as the objective,the optimal operation model of the cascade pumping station system is studied.Combined with the technical means of Jingdian project,such as the construction of regulation and storage tank and the selection of frequency conversion units,the dynamic balance state is achieved by improving the water level and flow of the cascade pumping station system,which greatly reduces the number of start-up and shut-down of the pump units,It can reduce the operation cost of the project,ensure the stable operation of the forebay of the pumping station with high water level and the safe operation of the pumping station and the channel,and achieve the purpose of optimizing the operation of the cascade pumping station system.