Cyber-Physical Coordinated Risk Mitigation in Smart Grids Based on Attack-Defense Game

Since modern smart grids have various and deeply coupled cyber-physical components, they are vulnerable to malicious cyber attacks. Although regular defenses including firewall and IDS are deployed, they may be weakened by zero-day vulnerabilities and sophisticated attack schemes. Therefore, defense strategies to mitigate the risk of blackouts during cyber attacks are necessary. This paper proposes a cyber-physical coordinated defense strategy to overcome the disruption and minimize the risk as much as possible. At the cyber layer, a zero-sum multilevel Markovian Stackelberg game is proposed to model sequential actions of the attacker and the defender. The defender distributes defensive resources to protect lines in a real-time manner, according to the attacker's action. If cyber attacks should result in physical outages, defense at the physical layer is then employed. A security-constrained optimal power flow reserving security margin of critical components will be performed to minimize the blackout scale and potential future risk. To solve the corresponding optimization problem and further get the optimal defense strategy, this paper devises a novel water-pouring algorithm. Lastly, test results show that the proposed dynamic defense strategy mitigates risk significantly and outperforms existing methods.

Automated summary

This paper proposes a cyber-physical coordinated defense strategy to overcome the disruption caused by cyber attacks in modern smart grids. It models the sequential actions of the attacker and the defender using a zero-sum multilevel Markovian Stackelberg game and employs a security-constrained optimal power flow at the physical layer. The proposed dynamic defense strategy mitigates risk significantly and outperforms existing methods.