Progressive Demand Control of Thermostatically Controlled Appliances for Power System Frequency Regulation

The high penetration of large-scale renewable generations challenges the stability of power systems. It is likely to causes frequency fluctuations due to the intermittent nature. Demand Response (DR) has received much attention because it balances generation and demand with flexibility. Unlike the costly conventional spinning reserve, thermostatically controlled load (TCL) can be controlled to provide frequency regulation service with little impact on customer comfort. A progressive demand control strategy is proposed in this paper for the system frequency regulation. In particular, the state shift priority method is proposed to optimally control loads without compromising customer comfort. The operation-cycle based random recovery method is developed to mitigate the load rebound. Case studies are conducted to validate that TCLs can provide a fast and smooth frequency regulation via the proposed control strategy.