Moving-Target Defense Against Cyber-Physical Attacks in Power Grids via\n Game Theory

This work proposes a moving target defense (MTD) strategy to detect\ncoordinated cyber-physical attacks (CCPAs) against power grids. The main idea\nof the proposed approach is to invalidate the knowledge that the attackers use\nto mask the effects of their physical attack by actively perturbing the grid's\ntransmission line reactances via distributed flexible AC transmission system\n(D-FACTS) devices. 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 formulate a\nzero-sum game to identify the best subset of links to perturb (which will\nprovide adequate protection) against a strategic attacker. The Nash equilibrium\nrobust solution is computed via exponential weights, which does not require\ncomplete knowledge of the game but only the observed payoff at each iteration.\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