A Generalized Battery Model of a Collection of Thermostatically Controlled Loads for Providing Ancillary Service

The thermal storage potential of Thermostatically Controlled Loads (TCLs) is a tremendous flexible resource for providing various ancillary services to the grid. In this work, we study aggregate modeling, characterization, and control of TCLs for frequency regulation service provision. We propose a generalized battery model for aggregating flexibility of a collection of TCLs. A theoretical characterization of the aggregate power limits and energy capacity of TCLs is provided. Moreover, we propose a priority-stack-based control strategy to manipulate the power consumption of TCLs for frequency regulation, while preventing short cycling on the units. Numerical experiments are provided to show the accuracy of the proposed model and the efficacy of the developed control method.