Distributed resilient event-triggered secondary control of microgrids against DoS attacks

Distributed secondary controllers based on sparse network for microgrids are not only vulnerable to malicious attacks, but also redundant on communications. As cyber-physical systems (CPSs), microgrids can achieve frequency and voltage restoration under secondary controllers governed by multi-agent systems (MASs). In this paper, a distributed resilient secondary control strategy is proposed for microgrids to eliminate the adverse effects caused by asynchronous denial-of-service (DoS) attacks. To avoid unnecessary energy wastes on communications between distributed generations (DGs), an event-triggered control strategy is designed for the secondary controller. To fully describe DoS attacks in microgrids, a more general attack model is built, in which valid and invalid DoS attacks are introduced. A time-triggered control strategy is proposed as a complement to the event-triggered control in order that objectives of the secondary control are achieved under DoS attacks. By using Lyapunov stability theory, it can be proved that the frequency and voltage will converge to the reference value. At the same time, the Zeno behavior can be excluded. Finally, the validity of the proposed secondary controller is verified through a microgrid simulation on MATLAB/Simulink.