Active disturbance rejection control for load frequency control systems under uncertainty and resonance attacks

The pervasive presence of hackers has seriously constrained the development of national cyber security. The necessity of addressing the issue of counteracting cyber-attacks is of paramount importance to the power grid system. In this study, we propose a novel attack compensation structure, namely the linear active disturbance rejection (LADRC) controller with a compensation loop. This enhances the existing second-order LADRC structure through incorporating a compensation loop that multiplies the difference between the output of the linear extended state observer (LESO) and the frequency deviation factor multiplied with RoCoF with a compensation factor controlled by a specific control law. The compensating attack loop drawing inspiration from LESO, possesses robust real-time online observation and estimation capabilities; effectively estimating and compensating for disturbances to stabilize system frequency within acceptable limits. The compensation loop employs three model-based resonance strategies to counteract disturbances, with detailed theoretical derivations and simulations conducted to determine the compensation factors. Simulation testing has been expanded to include two and three-area systems to validate the proposed approach. In addition, a comparison is made between the proposed compensation structure and the existing control scheme. The simulation results demonstrate that the proposed attack compensation scheme exhibits superior anti-attack capabilities while maintaining flexibility against resonance attacks.