Unsteady flow modelling of hydraulic and electrical RTC of PATs for hydropower generation and service pressure regulation in WDN

Abstract

ABSTRACT The topic of this paper is the recovery of energy from urban waters, which can be performed in water distribution networks (WDNs) through hydraulically and electrically regulated pumps operating as turbines (PATs). The time-varying operating conditions make real time control (RTC) techniques necessary for adjusting both hydropower generation and service pressure regulation. An unsteady flow model allows simulating the skeletonized layout of a real WDN, and assessing the effectiveness of the RTC. Two control schemes, operating at small and large-time steps, respectively, are presented and compared. The numerical simulations prove the application of the prototype feasible in real WDNs, providing effective hydropower generation and service pressure regulation. While the hydropower produced by the two controllers is similar, the first prevails in terms of closeness of the controlled pressure-head at the critical node to the desired set-point, whereas the second performs better in terms of control cost.