Vulnerability Assessment of Power Grid Using Graph Topological Indices

This paper presents an assessment of the vulnerability of the power grid to blackout using graph topological indexes. Based on a FERC 715 report and the outage reports, the cascading faults of summer WSCC 1996 are reconstructed, and the graphical property of the grid is compared between two cases: when the blackout triggering lines are removed simulating the actual sequence of cascading outages and when the same number of randomly selected lines are removed. The investigation finds that the critical path lengths of the triggering events of the July and August outages of 1996 WSCC blackout are higher than those of no-outage and arbitrary events. In addition, the small world-ness index for each of the outage triggering events is much smaller than that of normal or any no-outage scenario, indicating that events of shifting a network from small world to a random network would be more likely cascaded to wide area outage.