Controlled measurement set randomization-based moving target defense against coordinated cyber-physical attack in smart grids

Smart grids are at risk of a dangerously covert attack called coordinated cyber-physical attack (CCPA), which may cause large-scale line outages or even cascading failures. This is because that the damage of the physical attack can be masked by the coordinated cyberattack. Towards this goal, the attacker usually injects false data into the sensor measurements to manipulate the results of state estimation. In this paper, we propose a moving target defense (MTD) approach that applies controlled randomization to the set of measurements used in state estimation, which invalidates the attacker's prior acquired knowledge regarding power grids, and thus mitigates the coordinated false data injection (FDI) attack. To ensure that the measurement set is able to observe the system, a formal model with observability constraints is developed to select the measurements. Extensive simulations are performed on the standard IEEE bus systems using the MATPOWER simulator, and results show that the proposed MTD approach can prevent more than 50% of the states from being attacked.