Operational interdependency between electrical substations and road networks under extreme events

The critical infrastructure (CI) elements in the United States are highly interconnected and interdependent. Recent cases of extreme events–either nature or human-caused– have demonstrated ripple effects propagating from one critical infrastructure to another reflecting the interdependencies. Among many CIs, the electric power and transportation infrastructure systems exhibit a higher level of interdependencies, and it is vital to model electric power and transportation infrastructure system holistically to understand the vulnerable states from temporal and spatial dimensions considering interconnectedness and cascading effects. This study developed a graph-theory based analysis framework to model the interdependencies between the electric power and transportation infrastructure systems– road networks. The CI elements are integrated by building a heterogeneous graph that includes transportation road sections, electrical substations, utility headquarters, traffic signal nodes, and other relevant CI nodes. We report the results from a case study in Seattle, Washington considering different scenarios– network disruption types, traffic congestion level, and uncertainty in restoration time.