Active Demand-Side Management System to Facilitate Integration of RES in Low-Voltage Distribution Networks

This paper presents a demand-side management system designed for areas with high penetration of renewable energy sources. The system is based on the centralized direct control of electric water heaters (EWHs) with the objective to find the optimal dispatch of the EWHs so that the peak imports and exports of the controlled area are minimized. The EWH dispatch is computed utilizing two-stage optimization: the first stage computes the EWH load distribution on a longer time horizon, whereas the second stage corrects the dispatch in real time based on the instantaneous import or export. In cooperation with a local distribution system operator, a pilot installation of the proposed system has been implemented in a part of the distribution system of the Czech Republic. The simulations of a full participation scenario indicate that the system is capable of significant reduction of the peak imports and exports as well as the reduction of the overall energy transfers from and to the controlled area and associated power losses. The results also show that the proposed load control reduces voltage fluctuations in the controlled area.