Connectivity reliability and topological controllability of infrastructure networks: A comparative assessment

• Compares connectivity reliability (CR) and topological controllability (TC) metrics.
• Develops a controllability index and a controllability-based node importance metric.
• CR is more sensitive to degree while TC is more sensitive to degree heterogeneity.
• CR-based importance measures match TC-based measures for substation nodes.
• CR- and TC-based measures are complementary to identify important generator nodes.

As infrastructure systems evolve, their design, maintenance, and optimal performance require mature tools from system reliability theory, as well as principles to handle emerging system features, such as controllability. This paper conducts a comparative study of the connectivity reliability (CR) and topological controllability (TC) of infrastructure systems in terms of three aspects: topology, robustness, and node importance. Taking eight city-level power transmission networks and thousands of artificial networks as examples, this paper reveals that a dense and homogeneous network topology is better to satisfy CR and TC requirements, than more common sparse and heterogeneous networks when node attributes are generic. It is observed that the average degree's impact on CR is more significant than on TC, while degree heterogeneity is more significant on TC. When node attributes are accounted for, for generators the reliability-based node importance measure may underestimate some important nodes in terms of TC, and vice versa—an issue not observed for substation nodes. The findings in this paper suggest a potential new direction to enhance reliability-based design by integrating it with emerging controllability-based measures relevant in the future as infrastructure networks increase reliance on information systems.