Applying Complex Network Theory to the Vulnerability Assessment of Interdependent Energy Infrastructures

In this paper, we evaluate the use of statistical indexes from graph theory as a possible alternative to power-flow techniques for analyzing cascading failures in coupled electric power and natural gas transmission systems. Both methodologies are applied comparatively to coupled IEEE and natural gas test networks. The cascading failure events are simulated through two strategies of network decomposition: Deliberate attacks on highly connected nodes and random faults. The analysis is performed by simulating successive N-k contingencies in a coupled network, where the network structure changes with the elimination of each node. The suitability of graph-theoretic techniques for assessing the vulnerability of interdependent electric power and natural gas infrastructures is demonstrated.