Improved Network Reliability Optimization Model with Head Loss for Water Distribution System

摘要

A novel multiple reservoirs network optimization (MRNO) model is proposed to provide referable diameters of pipes that can be applied in water distribution network (WDS) design. Firstly, the shortest path between reservoirs and junctions is solved by the Dijkstra algorithm. Then, pressure losses of all pipes are solved by extended period simulation (EPS) and the minimum pressure loss of each pipe is selected. Thirdly, the diameter of each pipe is updated according to Hazen-Williams (HW) equation and new diameter values are given to pipes. Diameters of pipes are re-calculated in the next iteration until convergence or up to the maximum iteration time. Then, NSGA-II is employed to optimize network reliability, and the initial population at the first generation is the result of MRNO. Objective functions contain unit pipe cost, pressure uniformity function, and leakage uniformity function. For verifying the effectiveness of this model, HDP-SGA, NSGA-II, and SGA are employed as comparisons. Finally, five cases are selected to verify the practicability of this model. The results demonstrate that the network reliability of all WDSs has improved and pipe costs are reduced after MRNO-NSGA-II optimization.