Fast Regulation Service Provision via Aggregation of Thermostatically Controlled Loads

Federal Energy Regulatory Commission (FERC) Order 755 requires scheduling coordinators to procure and compensate more for regulation resources with faster ramping rates. Thermostatically Controlled Loads (TCLs) are a tremendous demand-side resource for providing fast regulation service due to their population size and their ability of being turned ON or OFF simultaneously. In this paper, we consider modeling and control of a collection of TCLs to provide such regulation service. We first develop a non-uniform bin state transition model for aggregate modeling of a collection of TCLs. The non-uniform model presents a potential for more accurate prediction while requiring fewer number of bins (reducing the complexity of the model) than the existing uniform bin models. We also propose a randomized priority control strategy to manipulate the power consumption of TCLs to track a regulation signal, while preventing short cycling, and reducing wear and tear on the equipment. The proposed control strategy is decentralized in the sense that each TCL makes its own decision solely based on a common broadcast command signal. This framework reduces the communication and computational efforts required for implementing the control strategy. We provide illustrative simulations to show the accuracy of the developed non-uniform model and efficacy of the proposed control strategy.