Selection and location of Pumps as Turbines substituting pressure reducing valves

Pressure control is a fundamental component of safe operation of water supply systems, mainly to reduce leakage, risk of disruption, and maintenance costs. System topology and topography can define high-pressure zones, and the use of Pressure Reducing Valves (PRVs) to maintain standard pressures in these zones is common. However, all energy available in the fluid is dissipated trough headloss. A turbine could be used instead of PRVs to produce electrical energy and to control pressure. The use of Pumps as Turbines (PATs) is recommended to reduce investment cost. Due to dynamic operations throughout the day, PATs operate under varying conditions of flow and head. This variation affects efficiency and headloss, which makes difficult the selection of PATs to substitute PRVs through conventional methods; therefore, this paper proposes a method for such selection. The method is based on maximization of energy produced, restricted to the system pressure limits. To solve this selection problem, the optimization technique of Particle Swarm Optimization (PSO) is used, and complete pump curves are used to simulate the PATs. In addition, this method is capable of identifying the best location on the network to install the PATs.