Non-iterative Application of Epanet for Modelling VSP in Water Distribution Network

Fixed speed pumps (FSP) exhibit optimal efficiency within their designated operating range. Nevertheless, the total water consumption during the day and the maximum flow rate could be two to three times higher than the average flow rate. The scheduling of pump operations is done with the aim of minimizing the cost of operating. However, it demands frequent on–off of pumps which compromises on the efficiency of pumps and results in increased operational costs. Variable-speed pumps (VSP) are becoming increasingly popular as a method to improve the efficiency of a pumping unit by expanding the optimal operating range for the VSP pump. A VSP adjusts its speed in real-time to accommodate changing demand, resulting in reduced on–off operations. The EPANET 2.0 and its latest version EPANET 2.2 allow for the modelling of a water distribution network (WDN) with pumps. The VSP can be indirectly simulated in EPANET using relative speed factors, which are calculated using the affinity laws. However, it is observed that the high variations between peak and lean flows and their respective head does not allows the FSP to mimic as VSP. In this paper, a new methodology is developed which does not depend on a single curve as it is required in modelling VSP using affinity laws. However, it uses EPANET for modelling multiple pump curves without using any relative speed factors with EPANET-PYTHON toolkit in a non-iterative fashion.