A tri-level optimization strategy incorporating wind power against coordinated cyber-physical attacks

With the fast development of cyber-physical power systems, coordinated cyber-physical attacks have become one of the main threats to the security of modern power grid. Considering that it is difficult for attackers to obtain full information of the entire power grid, the coordinated cyber-physical attack problem for partitioned power grid is studied in this paper, and a tri-level defender-attacker-dispatcher optimization model with consideration of wind power uncertainty in a specific coordinated cyber-physical attack mode is proposed. The Karush-Kuhn-Tucker (KKT) condition and an improved implicit enumeration algorithm are applied to obtain the solution of the complicated optimization problem effectively. In addition, two risk assessment indices pertinent to the physical lines and load measurements are proposed according to the obtained total amount of optimized load shedding and coordinated attack-defense strategy under valid attack-defense scenarios. Taking a partitioned IEEE 39-bus test system as example, the risks of physical transmission lines and load measurements in different areas under attacks are elaborately studied, and the impact of wind power uncertainty on attack-defense strategies is discussed as well. Numerical simulation results illustrate the effectiveness of the proposed optimization model and risk assessment indices, and some significant conclusions are drawn.