Developing and Testing a Unit-Commitment-Based Controller of Bus-Split Aggregated Residential Electric Water Heaters

Saleh S. A. , ÖZKOP E., Castillo-Guerra E., Pijnenburg P. C.

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, vol.56, no.2, pp.1124-1135, 2020 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 56 Issue: 2
  • Publication Date: 2020
  • Doi Number: 10.1109/tia.2019.2957432
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Aerospace Database, Applied Science & Technology Source, Business Source Elite, Business Source Premier, Communication Abstracts, Compendex, Computer & Applied Sciences, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.1124-1135
  • Keywords: Power demand, Water heating, Load flow control, Smart grids, Cost function, Load modeling, Energy storage, Bus-split (BS) aggregation, distribution systems, numerical methods, power system control, unit commitment (UC), THERMOSTATICALLY CONTROLLED LOADS, DEMAND RESPONSE, MODEL


This article develops and tests a controller for residential electric water heaters (EWHs). The developed controller is operated to maximize the energy stored in EWHs during off-peak-demand times, in order to reduce their power demands during peak-demand times. Desired control actions aim to adjust the minimum temperature settings of EWHs using the unit commitment (UC). In order to eliminate the need for a direct measurement of EWH power demands, the bus-split (BS) aggregation method is employed. The BS method is employed due to its ability to extract the power demands of an EWH from household power meter readings. The UC is formulated using the energy stored in a EWH as a cost function, which is to be maximized during the off-peak-demand time. The solution of the UC problem is obtained using the Lagrange relaxation method that can offer fast convergence and reduced computations. The BS-UC controller is implemented for performance testing using power meter readings that are collected from 150 residential households during the fall, winter, spring, and summer seasons. Test results demonstrate the ability of the BS-UC controller to provide accurate and effective control of EWHs, which are complimented by a minor sensitivity to the number controlled EWHs, hot water consumption, and seasonal variations in residential load power demands.