Development of a PDA model for water distribution systems using harmony search algorithm

Hydraulic analysis of water distribution systems can be divided into DDA (Demand-Driven Analysis) and PDA (Pressure-Driven Analysis). Many studies have reported the superiority of the PDA over the DDA in the realistic simulation of hydraulic conditions under abnormal operating conditions. Many of the developed PDA models rely on iterative processes to solve the equations, which is a time-consuming task and even worse it is not possible to solve them in some cases. To improve the efficiency of the PDA, the present study proposes a new PDA model which interfaces a hydraulic simulator and an optimization algorithm with a customized searching scheme. The suggested model is applied to differently sized water distribution systems under abnormal operating conditions and its results are compared with ones by the DDA model and two other PDA models. As results, the DDA may generate unrealistic hydraulic results under the abnormal operating conditions while the three PDA models produce more realistic results. Moreover, the suggested PDA model with the new optimization process simulates the hydraulic conditions under the abnormal operating conditions in large water distribution systems efficiently compared to the other PDA models.