Hierarchical decentralized control strategy for demand-side primary frequency response

The Grid Friendly™ Appliance (GFA) controller was proposed to autonomously switch off appliances by detecting under-frequency events. In this paper, a new frequency responsive load (FRL) controller is proposed by extending the functionality of the existing GFA controller. The proposed FRL controller can autonomously switch on (or off) end-use loads by detecting over-frequency (or under-frequency) events through local frequency measurement. Using the proposed FRL controller, a hierarchical decentralized control strategy is also developed for engaging the end-use loads to provide primary frequency response. The developed control strategy consists of two decision making layers including supervisory and device layers, and has several desirable features for primary frequency control. The FRL controller at the device layer preserves the autonomous operation of the enduse loads. The coordinator at the supervisory layer coordinates autonomous response to overcome the stability issue associated with high penetration of FRLs. The simulation results illustrate the effectiveness of the developed hierarchical decentralized control strategy in providing primary frequency response with the proposed FRL controller.