Countering AC Load Redistribution Attacks in Smart Grids: The Role of Moving Target Defense in a Defense-Attack Game

Abstract

Load redistribution attacks (LRAs) are a type of false data injection attack that disrupts the normal operation of the power grid by redistributing load. While most LRAs in the literature are based on the DC model, this paper proposes an LRA in the AC model using incomplete network information. To defend against the proposed LRA, the paper proposes using Moving Target Defense (MTD) to actively invalidate the attackers’ knowledge. A zero-sum defense-attack game is formulated between MTD and LRA to select an MTD operating range optimally, considering the trade-off between attack detection effectiveness and the extra operation cost. The paper defines a new payoff function as an expected incremental operation cost, consisting of the defense cost, attack cost, and attack mitigation capability. A Nash Equilibrium of the game provides optimal strategies for selecting the MTD operating range. Simulation results on the modified IEEE 14-bus system demonstrate the effectiveness of MTD in detecting the proposed LRA. The paper shows that MTD not only detects ongoing LRAs but also prevents the construction of such attacks by using the proposed game theoretical framework. The proposed approach highlights the role of MTD in enhancing the cybersecurity of power grids against LRAs.

Keywords

• AC load redistribution attacks
• moving target defense
• zero-sum game
• optimal strategy