Real-time Optimal Control of Water Distribution Systems

Abstract

This study attempts to develop a real-time optimal control model for water distribution network. The model aims to minimize operation cost by optimal control of pump system, while satisfying various operational constraints under demand fluctuations and energy tariff variations throughout operation period. The real-time control is realized using SCADA system, by which monitoring data is collected and the obtained control decisions are implemented. Optimal pump scheduling model is developed by combining demand forecasting, hydraulic simulation, and optimization models. Decision variables include pump on/off (binary code of 0/1) schedules for fixed-rate pumps for each time-step over pre-defined operation time horizon. Various operational constraints are applied such as, 1) maintaining system pressure near allowable minimum pressure avoiding excessive pressure to reduce energy consumption and non-revenue water, 2) maintaining tank water level within an appropriate range, and 3) peak energy consumption limit for each pump station. The proposed model follows four steps; step1) demand forecasting, step 2) system update based on SCADA monitoring data, step 3) optimizing pump/valve control decision, and 4) implementing current time control settings.