Phasor data correction and transmission system state estimation under spoofing attacks

Cyberinfrastructure (e.g., sensors, actuators and the associated communication network) has become an integral part of our modern power grid. While these cyber technologies enhance situational awareness and operational efficiency, they also expose the physical system to cyber-attacks. In this paper, we consider the problem of transmission system state estimation based on measurements from a number of PMUs. In this context, two PMU data integrity attacks namely, Time Synchronization Attack (TSA) and Man-in-the-Middle (MitM) attacks that can potentially cause a severe impact on the grid, are analyzed. Specifically, we propose a novel method based on an alternate expectation-maximization framework to mitigate the effects of these attacks on the state estimation process. Numerical tests are conducted on IEEE-14, 30 and 118 bus systems with different attack scenarios to validate the developed method. Unlike existing works, the proposed algorithm provides accurate state estimates without any prior knowledge of the location of the attack, the number of meters being attacked, or the magnitude of the attack parameter.