Characterization of Low-Frequency Oscillations in Autonomous AC Microgrids under Consensus VOI-Targeted False Data Injection Attacks

Autonomous distribution AC microgrids are often characterized by power lines with low X/R ratios, which lead to inherent active-reactive power coupling. Consensus-based virtual output impedance (VOI) control has been widely recognized for its ability to adapt and compensate for improving power coupling issues and regulation quality, as well as improving stability. To date, however, the susceptibility of this microgrid control structure to cyberattacks has remained largely unexplored. This paper shows that constant-type false data injection attacks (FDIAs) on the communication layer of the consensus-based droop control scheme can trigger low-frequency oscillations (LFOs), diminishing the power quality and causing stability issues. The numerical characterization reveals that if the pre-compensated physical X/R ratio is too low, there is a tendency for significant grid disturbances; if the X/R ratio is moderately low, the LFO characteristics are affected predominantly by the lowpass filter design, and to a much smaller extent by the load level (i.e., operating point). The LFO characteristics due to FDIAs, obtained from the multi-parametric consideration, lay the foundation for forthcoming theoretical analyses and mitigation techniques for improving the resiliency of droop-controlled microgrids with consensus-based VOI control.