The Application Of Improved Ant Colony Algorithms And Improved Hybrid Genetic Algorithms On The Optimization Of Water Distribution System

Water distribution system (WDS) is an important part of urban water supply system ,which is not only a bridge linking water treatment plant with customer, but also accounts for 50～80 percent of total investment and 30～50 percent of energy consumption of the total water supply system budget. The investment in rehabilitation is growing with the development of water use. The rationality of network programming, design and operating can affect the investment and reliability of water supply system. Therefore, it is very important and significant to make optimization for the WDS.This article use improved Ant Colony Algorithms for optimal layout to the tree water-pipe network,it can save investment and layout in reason,afford precondition for the optimal design and optimal attemper of water distribution system,then throught an example to validate,there is a very wide application in optimization of water distribution system.In order to get pipe flow and node pressure, it is necessary to have hydraulic analysis before the optimal design,this article choose EPANET(a hydraulic simulation software) to calculate.And the economyparameter must order before economy calculation,this article use the least square method to simulate by MATLAB.By analyzing the existed optimal mode of design to WDS, the author presents a multi-objective model based on economy and reliability. In the process of setting up the model, the reliability of WDS is defined as "weighted mean of nodal extra pressure" and "pipe network resilience", which will make it easy and direct to evaluate the reliability of WDS; at the same time, the annual cost is looked as the economical characteristic of WDS.Aiming at model's essence of combinational optimization with discrete variable, Combine improved genetic algorithm with EPANET to form improved hybrid Genetic Algorithms(IHGA), and which is used to the calculation of optimal design for complicated WDS. At the same time, the corresponding programme code is made too.Lastly, a typical example is used to prove the practicality and validity of the optimal model and IHGA, when compare to the traditional design method, the result shows that the IHGA have great meaning and value both in theory and in practice.