Droop Control Strategy for Inverter-Based Thermostatically Controlled Load Cluster Based on Frequency Threshold Preset Scheme in Hybrid Frequency Regulation Mode

Massive inverter-based thermostatically controlled load (ITCL) cluster has immense potential for frequency regulation. It is of great significance to tap its active frequency support potential. The hybrid frequency regulation mode provides a path for ITCL clusters to have primary frequency regulation (PFR) capabilities without the need for instant communication, centralized real-time computing, and complex control transformation. Thus, this paper proposes a frequency threshold preset (FTP) strategy in the hybrid frequency regulation mode to orderly preset the frequency response threshold for the decentralized ITCLs, so that the overall power dynamics of the ITCL cluster can present droop characteristic under the excitation of the power grid frequency deviation. Finaly, theoretical derivation and simulation case studies have confirmed the effectiveness of the proposed FTP strategy to enable PFR support of ITCL clusters.