Optimal Pressure Management of Drinking Water Distribution Network of Ezgele City with Emergency Connection between Pressure Zones Using NSGA-II

The occurrence of hydraulic problems during the repair of reservoirs in water distribution networks (WDN) is inevitable. In such cases, one of the reliable methods for water supply is emergency connection between pressure zones. However, the original design based on separated zone, loses its effectiveness and in some places, the WDN will face to increase and decrease in allowable pressure and even flow interruption. Therefore, in this study, the network analysis and determination of optimal 24-hour rule curve of pressure reduce valve (PRV) during an emergency connection between pressure zones, has been taken to reduce hydraulic difficulties. First, a computer model based on VB programming language was developed in which the network is analyzed by using slope matrix method. By linking mentioned model with the code that prepared for optimization by NSGA-II, the optimal rule curve of PRV in Ezgele WDN was determined. The results showed that in the case which lower zone reservoir become out of service and connecting node 12 of the higher zone with node 41 of the lower zone, it is necessary to install a pressure reduce valve on the outlet pipe of the higher reservoir. The optimal rule curve which was calculated during the day showed that the operating range of the pressure reduce valve is between 8 and 25 meters. The results also showed that when the higher zone reservoir is out of service during the maximum consumption, despite the connection between two zones, nodes 13 and 37 faces to absolute flow interruption and about 28% of the network suffers from pressure deficiencies in comparison to minimum allowable pressure.