Impact quantification of hypothesized attack scenarios on bus differential relays

The evolution of protective relays, from electromechanical to digital devices, has enhanced the system-wide monitoring and control. In most substation configuration, intelligent electronic devices (IEDs) of bus differential relays remain one of the most vital protection schemes to prevent equipment from overloading damage. The proposed study is to systematically identify the critical substation/IED hypothesized attack scenarios by eliminating large number of insignificant cases in an online environment. A statistical model combined with real-time simulation is proposed to identify the critical combinations of substation outages. The metrics include (1) substation risk index, (2) dependency of substation combinations, and (3) criticality of time windows which are validated using IEEE 30-bus system in this study. The results of combinatorial search based on a substation list are compared using depth first search (DFS), breadth first search (BFS), and random selection.