Secure Observer-Based Event-Triggered Control of Microgrid Load Frequency Control System Under DoS Attack

Abstract

This study proposes a secondary remote observer-based DoS attack tolerant event-triggered control framework for an islanded microgrid load frequency control system with virtual inertia/auxiliary control subsystem while accounting for multiple practical challenges. In this work, a microgrid configuration with a remotely located secondary controller and state observer is considered, and an event-triggered communication mechanism is adopted to enhance communication efficiency in the secondary control loop. The secondary observer and controller gains adhering to a prescribed $H_{\infty}$ performance bound are derived leveraging Lyapunov-Krasovskii functional-based stability analysis and DoS attack tolerance is achieved using a modified event-triggering condition accounting DoS-induced extra output error. The stability conditions are derived by considering key system challenges, including the time-varying secondary measurement path transmission delay, event-triggering condition, remote implementation of the observer, and additional output error induced by DoS adversary. Finally, the efficacy of the proposed secondary control approach is demonstrated using Monte-Carlo simulation across different disturbance scenarios.