Optimal rehabilitation model of water supply network with non-dominated genetic algorithm-II

To improve the objectivity of rehabilitation model for water supply network and provide more feasible solutions, a multi-objective rehabilitation model was developed by transforming the hydraulic constraints of the single objective model into objective functions, and the non-dominated sorting genetic algorithm-II (NS-GA-II) was used to solve the developed model. The test on a case of water supply network shows that a solution satisfied with all objectives can be obtained by considering the low pressure node, high load pipe and rehabilitation cost as objectives of rehabilitation model. The introduction of multi-objective concept and multi-objective oriented algorithm (NSGA-II) into the solving process of rehabilitation problem for water supply network overcomes the conflict between the rehabilitation model with one objective and that with multi-objectives, which avoids the uncertainties brought by using weight coefficients or punish functions. The introduction of artificial induction gene mutation operator accelerates the convergence speed of population, thus improves the convergence speed, which proves the feasibility of the method.