On the Resilience of Distributed Consensus Control to Multiplicative Cyberattacks

Distributed control is slated to be a key enabler of integrating converter-based generation at scale at the grid edge. The commonly-used consensus control for AC systems is known to be susceptible to malicious interventions that multiply communicated signals, potentially triggering voltage and frequency instability and tripping the converters. Considering a consensus control structure that ensures active and reactive power sharing as well as frequency restoration, we show that the voltage consensus loop is susceptible to such multiplicative attacks, whereas the frequency control loop is not. We then examine the various factors that influence the stability margin of the voltage consensus controller to attacks, with a view to identify behavioral trends. Ultimately, we determine the key instability mechanism to be the effect of the secondary control loop on the medium frequency poles corresponding to the network impedances, a finding which provides pathways to improve attack resilience.