Exploiting the inherent cyber resilience of inverter-dominated microgrids against PLL attack

This letter assesses the impact of phase locked-loop (PLL) cyberattacks on inverter-dominated microgrids considering the current limitation of the grid forming (GFM) and grid following (GFL) inverters. By reducing the PI gains of the PLL, an adversary can induce significant voltage sags by exploiting the dynamic coupling between the GFL’s synchronization loop and the GFM’s droop controller. The study demonstrates that preemptive tuning of lower droop gains in GFM inverters can mitigate the effects of such attacks. Leveraging this inherent cyber-resilience of inverter-dominated microgrids, an active decentralized droop adjustment mechanism is proposed. Power hardware-in-the-loop experiments validate the time-domain analysis and the effectiveness of the proposed mitigation strategy.