Aggregate Modeling of Thermostatically Controlled Loads for Microgrid Energy Management Systems

• Published in: IEEE transactions on smart grid Vol. 14; no. 6; p. 1
• Main Authors: Cordova, Samuel, nizares, Claudio A. Ca, Lorca, Alvaro, Olivares, Daniel E.
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.11.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aggregates; Alternative energy sources; Batteries; Biological system modeling; Computational modeling; Distributed generation; Dynamic models; Electrical loads; Energy management; energy management system; Energy management systems; Flexibility; Frequency control; frequency dynamics; Irradiance; Load control; Mathematical models; microgrid operation; Microgrids; short-term fluctuations; virtual battery
• ISSN: 1949-3053; 1949-3061
• DOI: 10.1109/TSG.2023.3254655

Second-to-second renewable power fluctuations can severely hinder the frequency regulation performance of modern isolated microgrids, as these typically have a low inertia and significant renewable energy integration. In this context, the present paper studies the coordinated control of Thermostatically Controlled Loads (TCLs) for managing short-term power imbalances, and their integration in microgrid operations through the use of aggregate TCL models. In particular, two computationally efficient and accurate aggregate TCL models are developed: a virtual battery model representing the aggregate flexibility of TCLs considering solar irradiance heat gains and wall/floor heat transfers, and a frequency transient model representing the aggregate dynamics of a TCL collection considering communication delays and the presence of model uncertainty and time-variability. The proposed aggregate TCL models are then used to design a practical Energy Management System (EMS) integrating TCL flexibility, and study the impact of TCL integration on microgrid operation and frequency control. Computational experiments using detailed frequency transient and thermal dynamic models are presented, demonstrating the accuracy of the proposed aggregate TCL models, as well as the economic and reliability benefits resulting from using these aggregate models to integrate TCLs in microgrid operations.