Optimal power grid protection through a defender-attacker-defender model

Power grid vulnerability is a major concern of our society, and its protection problem is often formulated as a tri-level defender-attacker-defender model. However, this tri-level problem is computationally challenging. In this paper, we design and implement a Column-and-Constraint Generation algorithm to derive its optimal solutions. Numerical results on an IEEE system show that: (i) the developed algorithm identifies optimal solutions in a reasonable time, which significantly outperforms the existing exact algorithm; (ii) the attack solution obtained through solving the attacker-defender model does not lead to the optimal protection plan in general; and (iii) protection using the optimal solution from the defender-attacker-defender model always improves the grid survivability under contingencies. The proposed model and algorithm can be easily modified to accommodate for other critical infrastructure network protection problems.