Abstract: Motivation: Energy infrastructure is a critical underpinning of modern society. To ensure its reliable operation, a nation-­‐wide or continent-­‐wide situational awareness system is essential to provide high-­‐resolution understanding of the system dynamics such that proper actions can be taken in real-­‐time in response to power system disturbances and to avoid cascading blackouts. The power grid represents a typical highly dynamic cyber-­‐physical system (CPS).