Optimal operation of urban tidal drainage pumping station based on genetic algorithm coupled with head-water level successive approximation

Abstract

Aiming at the method of solving the optimization scheme for urban tidal drainage pumping stations during heavy rainfall below the urban drainage design standard, and the problems such as the mismatch between the head and water level of pumping stations at each divided time period during the solution process, a nonlinear mathematical model for optimal operation of urban tidal drainage pumping station was constructed which took the minimal operation cost of drainage pumping station during given operating period as the study target, and the blade angle of each pump unit in each divided time period as decision variables with the constraints of total water quantity of target drainage, matched motor power of each pump unit, water level of in the drainage area, number of switches and the shortest operation time of pump unit. For the problem of head-water level mismatch at each divided time period of pumping station, the genetic algorithm of coupled head-water level successive approximation is proposed, which can make the optimization scheme realize the matching of river network water level and pumping station operating head. Taking Guazhou Pumping Station in Yangzhou City of Jiangsu Province encountering 10% frequency designed rainfall as an example, optimization schemes under typical working conditions which included different starting drainage water levels and peak-valley electricity prices was obtained, as well as the influence of electricity price of divided time period, average head of each divided time period and inflow on the optimization scheme was carried out. The unit optimal operation drainage costs of Guazhou Pumping Station is 45.46 yuan/104 m3 and 51.32 yuan/104 m3 respectively when the starting drainage water level is set as 4.8 m and 4.6 m, which has the corresponding operation benefit of 15.34% and 4.40% less than that of conventional operation, and the water level variation of river network has dropped 6.61% and 7.85% than that of conventional operation. The constructed optimal operation model of urban tidal drainage pumping station and the proposed solution method can effectively improve the matching degree of pumping head and water level variation, and effectively make a compromise of economic operation of drainage pumping station and the safety requirements of water level control of river network in drainage area. The obtained optimization schemes can offer decision-making reference for relevant dispatching and management departments of drainage pumping stations.