Discrete-time resilient-distributed secondary control strategy against unbounded attacks in polymorphic microgrid

This study proposes a polymorphic cooperative control system for microgrid consisting of a service layer, a control layer, a data layer, and a power layer to apply a resilient-distributed secondary control strategy to distributed generators (DGs) from different manufacturers more conveniently. Due to the improvement of network openness, external cyberattacks are more likely to tamper with the neighbor information transmitted in the cooperative control system. In this study, a discrete-time resilient-distributed secondary control strategy is designed to resist potential unbounded false data injection (FDI) attacks, which introduces a virtual network layer interconnecting the control network layer to form a layered network. The strategy can maintain the stability of voltage and frequency under unbounded attacks and then greatly suppress the state estimation difference of voltage and frequency. Meanwhile, the unbounded attack depending on voltage and frequency estimation difference is suppressed to a nearly bounded attack. Finally, a microgrid consisting of six inverter-based DGs is taken as an example to validate the effectiveness of the strategy against unbounded attacks.