An edge load cascading failure model and vulnerability analysis of coupled critical infrastructure networks: Considering functional and geographical interdependency

Infrastructure networks are not isolated, but rather highly interconnected and interdependent. The flow characteristics of loads within the network and the existence of interdependencies between networks can lead to cascading failures throughout a region or country when one component is disrupted. The general focus is on analyzing infrastructure networks from the intra-layer structural perspective; it is less understood the coupling mode of interdependency between layers and the loads on the network. This paper proposes a new cascading failure model based on edge load, taking into account both intra-layer network structure and inter-layer functional and geographical interdependencies, while also explores the impacts of different factors on the cascading failures. Results show that nodes with strong dependencies, especially parent-dependency, play vital roles in supporting coupled networks. It compares the vulnerability differences of the system under different attack strategies based on intra-layer structure and inter-layer correlation, finding the outcome changes with functional interdependency strength and geographical distance. This study assesses relevant factors affecting the vulnerability of interdependent infrastructure networks from a modeling perspective. Meanwhile, compared with the traditional model, the new model can better resist the spread risk of cascading failures, thus providing valuable lessons for guiding realistic system construction.