Security Enhancement of Power System State Estimation With an Effective and Low-Cost Moving Target Defense

Moving target defense (MTD) is a new defensive mechanism developed in power systems to thwart false data injection attacks (FDIAs). However, since the MTD works by perturbing the branch parameters with the distributed flexible ac transmission system (D-FACTS), it might cause additional infrastructure and operation costs and affect the system dynamics. This is a complicated problem because it is closely related to which branches should be perturbed and how much they are changed. In this article, we analyze the essentials of MTD and construct an effective and low-cost MTD. To begin with, we provide a sufficient and necessary condition for MTD to protect a bus from being affected by the intended FDIA. Based on this result, we propose a new metric to quantify the protection level of MTD and an efficient algorithm to minimize the number of required D-FACTS devices for protecting a specific set of buses. To reduce the operation cost, we develop two strategies to make the increasing operation cost zero for activating the MTD. Furthermore, we analyze the impact of MTD on the system dynamics with a special emphasize on small signal stability. Finally, we conduct extensive simulations to validate our findings with the test cases of power systems in MATPOWER.

Automated summary

This article investigates the mechanism of Moving Target Defense (MTD) in power systems to counter False Data Injection Attacks (FDIAs) and develops an effective and low-cost MTD. A sufficient and necessary condition for protecting buses from intended FDIAs is provided, along with a new metric to quantify the level of protection and an efficient algorithm to minimize the number of required D-FACTS devices. Two strategies are proposed to reduce the operation cost of activating MTD, and the impact of MTD on system dynamics, particularly on small signal stability, is analyzed.