Use of Hydraulically Operated PRVs for Pressure Regulation and Power Generation in Water Distribution Networks

In recent years, power generation has been coupled with pressure regulation to optimize management of water distribution networks, also showing attractive revenues and short payback periods. A recent study proposed a prototype that performs both electric and hydraulic regulation for pressure regulation and hydropower generation in a water distribution network, wherein laboratory experiments showed the effectiveness of the control algorithms and the prototype's capability in regulating pressure at the desired set-point value while optimizing power production. However, the prototype uses needle valves for flow and pressure regulation, whereas hydraulically operated pressure-reducing valves (PRVs) can be more effective for pressure regulation. Moreover, such PRVs require much less power for operation, thus proving more reliable in case of electrical blackout. Consequently, a different prototype was proposed, which uses hydraulically operated PRVs instead of needle valves. This paper discusses the control algorithm of the system to achieve pressure regulation and optimal power generation. A proportional integral controller was used for PRV control, whereas the inverter control was performed by means of both an external optimization module and dimensionless variables. Laboratory experiments confirmed the effectiveness of the proposed approach and pointed out the effect of the gains on the process dynamics.