An Improved Defender–Attacker–Defender Model for Transmission Line Defense Considering Offensive Resource Uncertainties

Developing efficient strategies for defending electric power systems against attacks is a major concern for contemporary power grids, especially when uncertainties are involved. This paper addresses the allocation of the defensive resource to minimize the damage when there are uncertainties regarding the resource that the attacker has. A multiple-attack-scenario (MAS) defender-attacker-defender (DAD) model is proposed by extending the conventional trilevel DAD model. The proposed model considers the uncertainties related to the offensive resource and the interactions involving the security personnel at the top-level, the attacker at the middle-level, and the power system operator at the bottom-level. The column-and-constraint generation algorithm is implemented by decomposing the MAS DAD model into an upper-level problem for the security personnel, and a lower-level problem for the attacker involving the optimal power flow analysis-based corrective power redispatch implemented by the power system operator. Case studies are performed based on the IEEE RTS79 and 57-bus systems, and the results validate that the proposed method is able to minimize the damage when uncertainties are involved in the offensive resource. This paper can offer meaningful insights into power system protection involving uncertainties.

I. Introduction

The cyber-physical security of electric power grids is an increasing concern in both planning and operation during recent years with the wide deployment of smart grid technologies and the growing vandalism/terrorism activities. As a critical infrastructure, the power grid is subject to various kinds of attacks in the forms of cyber intrusions and physical disruptions, and cyber-physical coordinated attacks. Once critical components are tripped due to attack, there might be a tremendous economic loss, equipment damage and even great panic in the society. Therefore, in recent years there is an increasing concern about the cyber-physical security of power systems around the globe [1].