Multi-objective Optimization of Cross-basin Water Pump Station Solved by the Pareto Method

Abstract

【Background and objective】 Previous studies have shown that optimal operation of pumping stations needs to frequently adjust the angle, variable speed, start and stop of pump units. These could result in a great variation in pumping rate between the units, forming a large reflux area or refractive flow in the outlet pool of the station, giving rise to wall erosion. Existing studies did not consider optimization of the erosion of the outlet water flow. Long-term operation of the pumps under such conditions could have serious consequences. The objective of this paper is to investigate the basic requirements of water extraction target realization and unit operation life, how to better balance the economy and safety in the operation process and realize the multi-objective optimization operation of pump station. 【Method】 Nonlinear and multi-objective optimization operation of the pumping station was established with the minimum water extraction cost and the minimum flow unevenness between units in the station as the objectives; the blade placement angle of each unit in each period of the water transfer cycle were the decision variables. Taking Jiangdu No. 4 Station of the Eastern Route of South-to-North Water Diversion as an example, the typical calculation and analysis under different daily head and water lifting load were calculated considering the influence of peak-valley time-of-use price. 【Result】 Comprehensively considering the safety and economy of pumping station operation, under 100%, 80% and 60% water lifting load, the water lifting cost per ten thousand m3 corresponding to the optimal operation scheme of the fourth Jiangdu Pumping Station is saved by 12.44%, 14.26% and 3.69% on average compared with the conventional operation scheme, and the flow unevenness between units is significantly reduced compared with the scheme considering the economic operation target alone. 【Conclusion】 Compared with the single operation cost or the minimum energy consumption commonly used in the research on the optimal operation of cross-basin water transfer pumping stations (groups) in China and abroad, the safety of pumping station operation can be effectively taken into account under the premise of meeting the demand for water supply, and the safety hidden danger in the process of optimal operation of pumping station can be effectively reduced. The research results can be used for reference by the operation and management units of similar projects.

Keywords

• pumping station
• multi-objective optimization
• operation
• multiple units
• pareto optimal solution