Secondary Defense Strategies of AC Microgrids Under Polynomially Unbounded FDI Attacks and Communication Link Faults

This letter presents fully distributed, resilient secondary defense strategies for AC microgrids considering both communication link faults and a broader spectrum of unbounded false data injection (FDI) attacks on control input channels. In contrast to existing solutions that address bounded faults or unbounded attacks on the input channels with bounded first-order time derivatives, the proposed strategies aim to enhance the defense capabilities against polynomially unbounded FDI attacks while the communication links are under faults. Resilient defense strategies for AC microgrids are developed to mitigate the adverse effects of the polynomially unbounded FDI attacks on control input channels and communication link faults, ensuring the stable and resilient operation of AC microgrids. Through rigorous Lyapunov-based stability analysis, the formal certification of the proposed strategies is demonstrated in achieving uniformly ultimately bounded convergence in frequency regulation, voltage containment, and active power sharing in multi-inverter-based AC microgrids. The effectiveness of these resilient strategies is further validated on a modified IEEE 34-bus test feeder system with four inverter-based distributed energy resources.