Improving AC Microgrid Stability Under Cyberattacks Through Timescale Separation

The reliance on communication in the secondary control of converter-based microgrids leaves them vulnerable to multiplicative false data injection attacks (FDIAs) that maliciously amplify communicated signals, disrupting the synchrony of the sources. In this brief, we identify the root cause of susceptibility to be the violation of timescale separation between the primary and secondary control layers. We leverage this finding to directly improve the system resilience to such attacks without the need to detect and nullify the attack vector, eliminating the need for additional sensors and communicated signals solely for resilience. Specifically, a fixed-design lag compensator added to the voltage consensus controller to enforce timescale separation is shown to increase the instability threshold for the tampered signals by over 300 times, using a representative case study.