Multi-Node real time control for pressure regulation and energy recovery in water distribution networks using Pump-as-Turbines

Leakage reduction is an extremely important goal in the management of Water Distribution Networks (WDNs). Due to the dependence of leakage on pressure, Real Time Control (RTC) represents an effective tool to mitigate leakage by dynamically removing pressure excess as the users demand varies during the day. Cost-effectiveness of RTC can be improved by transforming part of the pressure excess into electric energy. This result can be achieved by means of Pump-as-Turbines (PATs). This paper proposes a novel RTC scheme able to simultaneously regulate pressure at multiple WDN nodes, and recover part of the excess energy, which can be sent directly to the main electrical grid. The control scheme is based on a Kalman Filter for joint state and disturbance estimation, a tracking Model Predictive Controller for multi-output regulation, and an Actuator Settings Optimiser to adjust the PAT settings. Thanks to its modular structure, the algorithm is scalable, flexible, and computationally cheap. The effectiveness of the proposed RTC scheme is demonstrated with several closed-loop simulations, carried out on a detailed, pressure-driven, unsteady flow model of an existing WDN. Moreover, the proposed algorithm can be directly applied to real WDNs, as it does not require any hydraulic model of the entire plant to be designed and tuned.