Leakage Control Of Water Distribution Systems Based On Many-objective Optimization

Water distribution system(WDS)is an important infrastructure for the social and economic development of modern cities.However,China’s leakage problem is very serious,from 2013 to 2017,the annual leakage amount in China was more than 7 billion m~3,with an average leakage rate of about 15%,with some cities exceeding 25%.Network leakage will not only cause the waste of high-quality water and energy,if not controlled,it will even develop into a pipe explosion accident,affecting the normal life of residents.According to the suggestion of leakage control specialist by IWA,the real leakage control strategy includes leakage detection,pressure control and network rehabilitation.The last two methods usually need to establish the leakage control optimal model.Traditional optimization models usually only consider the two objectives of cost and leakage,the Pareto solution between cost and loss is obtained by a specific algorithm(e.g.genetic algorithm),and choose the appropriate pressure control strategy or network rehabilitation.However,the traditional leakage control model ignores the influence of leakage control measures on the reliability and water quality of WDS.Aiming at the above problems,this paper proposes a leakage control optimal model based on many-objective optimization.This model considered four objectives,which is cost,leakage,reliability and quality.Borg is used to solve the model.In order to verify the advantages of the many-objective optimization model,this study analyzes the Pareto solution by the whole solution set distribution,TOPSIS ranking and representative scheme.Two benchmark are used to verify the advantages of the proposed model.One is 25-nodes network,which considered a many-objective optimization model and a traditional model。Another is Anytown,which considered two many-objective optimization model and three traditional model.This study proves the advantages of many-objective optimization model in leakage control of WDS.Compared with the traditional model,the many-objective optimization model can provide decision makers with more diversified schemes.Furthermore,pareto solutions from proposed model contained the solutions which not only perform better in four functions,but performed much better in reliability and water quality only increased litter leakage.On the other hand,the relationships among the functions of the five-objections model are compared,it is found that increasing the capital cost and operational cost both can reduce the leakage.And the relationship between capital cost and resilience is not obvious,while increasing operational cost can obviously improve the resilience.In this paper,the leakage control method based on many-objective optimization can effectively avoid the possible decision errors and negative effects caused by the traditional method,which provides an important reference for leakage control.