Iterative Extended Lexicographic Goal Programming Method for Fast and Optimal Pump Scheduling in Water Distribution Networks

Pump scheduling in water distribution networks is important, especially with current high energy prices. A good pump schedule is one that reduces pump energy and maintenance costs without worsening the overall system performance. Because of the nonlinearity of the hydraulic energy balance equations and the complexity of water distribution networks, pump scheduling problems cannot be easily solved by hand, especially in the general case of a network with multiple tanks and pumps/pumping stations. A number of approaches exist in the literature addressing the trade-off between effectiveness (i.e., optimality of schedules generated) and computational efficiency, but there seems to be no ideal solution. In this paper, an effective and efficient optimization method, the iterative extended lexicographic goal programming (iELGP), is developed to solve a least-cost pump scheduling problem. The method is tested on two multitank networks. The results obtained demonstrate that by using the iELGP method, an optimal pump schedule can be obtained with high computational efficiency which makes the method suitable for real-time application.