  During major power system disturbances, when multiple component outages occur
in rapid succession, it becomes crucial to quickly identify the transmission
interconnections that have limited power transfer capability. Understanding the
impact of an outage on these critical interconnections (called saturated
cut-sets) is important for enhancing situational awareness and taking correct
actions. This paper proposes a new graph theoretic approach for analyzing
whether a contingency will create a saturated cut-set in a meshed power
network. A novel feature of the proposed algorithm is that it lowers the
solution time significantly making the approach viable for real-time
operations. It also indicates the minimum amount by which the power transfer
through the critical interconnections should be reduced so that
post-contingency saturation does not occur. Robustness of the proposed
algorithm for enhanced situational awareness is demonstrated using the IEEE-118
bus system as well as a 17,000+ bus model of the Western Interconnection (WI).
Comparisons made with different approaches for power system vulnerability
assessment prove the utility of the proposed scheme for aiding power system
operations during extreme exigencies.
