Optimum interface topologies between urban infrastructure systems

This paper proposes an approach to design the interface topologies between complex infrastructure systems. Based on infrastructure topological and geographical features and reliability information, four types of interface design strategies are formulated based on maximum node degree, maximum node betweenness, minimum Euclidean distance, and highest reliability ranking. To compute and compare interface effectiveness, annual cascading failure effect (ACFE) metrics are proposed and then ACFE-based cost improvement (ACI) metrics relative to a reference design strategy are also introduced to consider their effectiveness per kilometer increment of interface line length. Taking the power grid and gas pipeline system in Harris County, Texas, USA as an example, an optimum strategy is found and discussed. Results show that the reliability ranking based strategy minimizes the ACFE metric, and when compared to the reference strategy its ACFE decreases by 0.9%similar to 14.3% per kilometer increment of interface length under different power grid safety margins.