Anomaly Observer-Based Cyber-Resilient Torque Control Against Hybrid Attacks in Wind Turbines

Inspired by the continued focuses on renewable energy cybersecurity issues, this paper aims to propose a cyber-resilient torque control framework for wind turbines to defend against the hybrid attack. The cyber threat model is established combining denial-of-service and data manipulation attacks, which attempts to destabilize the wind turbine system by implementing the attacks on the communication link from the rotor speed sensor to the controller. Particularly, the impact of hybrid attack is analyzed and classified into two cases, and the corresponding compensatory measures are developed. To mitigate the impact of the hybrid attack and stabilize the wind turbine system, a cyber-resilient torque control scheme combining zero-order holder and anomaly observer is proposed, which requires simple computational ability of the wind turbine system. Using the Lyapunov theory, the control target of optimal rotor speed tracking is guaranteed and the tolerable attack range under the proposed method is derived. Extensive studies are carried out on a 1.5 MW doubly-fed induction generator-based wind turbine, and the simulation results indicate that the proposed control strategy could effectively reduce the impacts caused by the hybrid attack.