Optimization of Energy Costs Considering Hydraulic and Quality Reliability Using Ant Colony Algorithm

Energy costs comprise considerable amount of operation costs in water distribution networks. Optimal management of energy costs to provide required water for consumers with desired quality is of high importance. To achieve this, optimization is defined as a powerful tool. In this paper, by focusing on operation phase, multi-objective optimization of water supply network considering hydraulic, quality and integrated reliability measures is performed. In each of these cases, the first goal is to minimize energy costs and maximization of each reliability measure is considered as the second objective. Therefore, it is necessary to set the performance schedule of the pumps over a period of time, one day, such a way that pumping schedual changes based on consumption variation during the day. In addition, it is required to maximize the hydraulic, quality and integrated reliability measures in the network. In this paper, in order to adapt more pump operating modes of pump station, both constant and variable speed pumps are used. In order to optimize performance of water distribution network, due to the high efficiency and simplicity of ant colony algorithm, the NA-ACO-CD (Non-Dominated Archiving Ant Colony Optimization with Crowd Distance) algorithm has been coded in Visual Studio C. The efficiency of NA-ACO-CD algorithm is tested with mathematical functions and proved to be applicable on water distribution networks. The proposed method is evaluated on Anytown water distribution network and required pareto curved are produced. It is concluded that the methodology cannot be attained to a combination of pump speeds such that all three pump, hydraulic and quality reliabilities will be maximized simultaneously.