Fallback Control for Isochronous Energy Storage Systems in Autonomous Microgrids Under Denial-of-Service Cyber-Attacks

This paper investigates and proposes a mitigation strategy for denial-of-service (DoS) cyber-attacks, targeting the most critical distributed energy resource (DER) in an islanded microgrid featuring a high penetration of renewables; the energy storage system (ESS) operating as the isochronous generator that forms and regulates the microgrid voltage and frequency. A rule-based fallback control strategy is proposed to enhance the resiliency of the microgrid to DoS cyber-attacks by managing the ESS state-of-charge in a decentralized manner, such that it can continue operating as the isochronous DER, while dispatching the remaining DERs in a centralized manner. Supplementary control loops are added to the ESS to manage and coordinate, using local frequency signals, with the remaining DERs, whose local controllers are specifically designed to provide frequency support in the event of DoS cyber-attacks. The proposed scheme is applied on a 25 kV islanded microgrid under two configurations, synchronous machine-based and 100% inverter-interfaced, and its effectiveness is validated on a real-time hardware-in-the loop testing platform.