Moving-Target Defense for Detecting Coordinated Cyber-Physical Attacks\n in Power Grids

This work proposes a moving target defense (MTD) strategy to detect\ncoordinated cyber-physical attacks (CCPAs) against power grids. A CCPA consists\nof a physical attack, such as disconnecting a transmission line, followed by a\ncoordinated cyber attack that injects false data into the sensor measurements\nto mask the effects of the physical attack. Such attacks can lead to\nundetectable line outages and cause significant damage to the grid. The main\nidea of the proposed approach is to invalidate the knowledge that the attackers\nuse to mask the effects of the physical attack by actively perturbing the\ngrid's transmission line reactances using distributed flexible AC transmission\nsystem (D-FACTS) devices. We identify the MTD design criteria in this context\nto thwart CCPAs. The proposed MTD design consists of two parts. First, we\nidentify the subset of links for D-FACTS device deployment that enables the\ndefender to detect CCPAs against any link in the system. Then, in order to\nminimize the defense cost during the system's operational time, we use a\ngame-theoretic approach to identify the best subset of links (within the\nD-FACTS deployment set) to perturb which will provide adequate protection.\nExtensive simulations performed using the MATPOWER simulator on IEEE bus\nsystems verify the effectiveness of our approach in detecting CCPAs and\nreducing the operator's defense cost.\n