Cyber-Physical Systems of Microgrids for Electrical Grid Resiliency

Abstract

Microgrids are increasingly being adopted in distribution systems to maintain operation of electrical systems in adverse situations, such as storms or cyber attacks. Modern microgrids rely on cyber communication for fast measurement and control of intelligent distributed energy resources (DERs), making microgrids complex cyber-physical systems. This work presents control strategies, as well as approaches for resiliency to attacks against measurements, system stability, and secure communications within and between partitions when microgrids are islanded from the utility area electric power system. Modes of graceful degradation, whose objective is to continuously serve identified critical loads, are presented. Finally, we conclude with a use case that unifies all concepts, in which we mitigate effects of an attack against generation on a critical load bus. Mitigation is achieved by consensus between controllers for peer systems to close a normally open tie line between two systems. The attack is detected, the suspicious DER is tripped, and the appropriate tie line between the two systems is closed to continuously supply the critical load. Rapid, secure communication of measurements between the systems allows the stability algorithm to restore stability of the now-combined system within an acceptable time interval. Results from real-time simulation are provided to validate the effectiveness of our approach.