Research On Key Technologies Of Energy-saving For Small Pumping Station System

The research on key technologies of energy-saving for small pumping station system is of great theoretical guiding and practical significance. This project is supported by a water conservancy technology key project of Jiangsu Province （No:2009024） and the college graduates’scientific and technological innovation project of Jiangsu Province （No:CXLX11₁005）, which is named by "the key technologies and its application for small pumping station energy-saving transform" and "the key technologies and its application for small and medium pumping station energy-saving transform" respectively.Field investigations were carried out among dozens of irrigation and drainage pumping stations of Hanjiang District of Yangzhou. The states of mechanical and electrical equipments, the pump units, the management levels and so on for different types of small pumping stations were grasped adequately. With the calculation and analysis of energy losses and system efficiencies for three typical pumping station systems, key factors which reduce the efficience of small pumping station systems were researched and the corresponding energy saving potential was analyzed. In accordance with the Key links which enjoy a larger potentiality of energy saving, comprehensive and systematic studies were developed with the combining methods of theoretical calculations and analysis and three-dimensional numerical simulation technologies, and sets of key technology programs of energy-saving transformation for small pumping station systems were summarized. Main works and innovation conclusions are obtained as follows:（1） The energy losses of the components apart from pump units including the water transferring canals and the power transmission and transformation facilities, account a large proportion and can’t be neglected. So taking the water transferring canals and the power transmission and transformation facilities as the component elements of small pumping station systems, and analysizing the energy losses and efficiencies for each part from the perspective of the whole system is of great practical significance. Taking Yun-xi drainage pumping station as an example, the percentages of which comes to23%of the system total energy losses, thus energy-saving potential is great.（2） Replace the obsolete mechanical and electrical equipments timely and Choosing pump, mechanical and electrical equipments reasonably to improve the efficiency of the pump units. While determining the type of pumps, so as to improve the efficience of pumping units, the method of envelope line considering the time intensity distribution of annual operation head of pumping station and the method of increase the flow with equal lift are desirable.（3） Increase the flow area of water conveyance culverts appropriately can improve the efficience of water conveyance remarkably. Optimize the structure and size of the fore bay, suction sump and outlet sump, desilting periodically and cleare out the drain before the trash racks timely can improve the pumping in and out flow pattern and reduce the hydraulic both of lengthwise and local.（4） With the method of three-dimensional numerical simulation technologies,the head losses of the outlet for different pumping stations were calculated and analyzed, considering different diameters, location heights and angles of the outlet pipes and the structure size of the outlet sumps.Though optimizing the form of outlet sumps, the head losses can reduce0.05～0.29m.（5） For behind-levee drainage pumping stations, the relationship model for the position height of culvert through levee and the cost of outlet project construction and operation of the pumping station was established. Taking typical project as an example, assuming the working life of the pumping station is25years and the annual service hours are360hours, the total cost is minimal while the depth from the levee crest to the top of culvert is1.75m and the annual operation cost is reduced by8.13%and the total cost could be saved by72.6thousand Yuan compared with outlet open channel.The integrated application of new technologies summarized by this paper were applied to the reform of two puming station systems,and the effect of energe-saving and capacity-increasing are remarkable. Among which the efficience of Yun-xi drainage pumping station system was improved by13.81percentage points, and the flow of the pump units of Dun-liu irrigation pumping station were increased by41.69percentage points and85.94percentage points respectively and the efficience for each pump unit was increased by23.72percentage points and29.26percentage points respectively, which indicates the economic and social benefits are remarkable.