Interdependent systems, such as the smart-grid, are rapidly emerging as the underpinning technology for major industries in the 21st century. Such systems are often more fragile in the face of node failures, attacks, and natural hazards than their isolated counterparts. This is because failures in one network may propagate to other networks and vice versa, leading to a cascade of failures that can potentially collapse the entire infrastructure. Mitigating these risks is critical for the successful development and evolution of many modern systems including the smart-grid. Traditional network science focuses on single networks, and thus lacks the methods and tools necessary to address vulnerabilities of even simple interdependent networks. This project aims to advance the state-of-the-art in modelling, controlling, and optimizing the robustness of interdependent networks by exploring several novel research directions. The first phase targets a study of robustness of interdependent networks under various topologies when nodes in one network may depend on more than one node of another network, and vice versa, aiming to characterize the critical fraction of nodes whose failure will lead to the collapse of the entire system. This also exposes the trade-off between network robustness and the number of inter-connections (or resources) allocated. The study then advances to optimal allocation of support-dependency links to maximize the robustness of the smart-grid, seeking to characterize the distribution that will lead to maximal robustness. The results aim to articulate concrete design guidelines on how available back-up resources should be allocated in order to best sustain i) random node failures; and ii) targeted attacks. Successful completion of the project will require the development of new techniques and approaches in the fields of network science, discrete optimization, and random graph theory, together with acquisition and analysis of real-world data from existing smart-grid networks.
Given the sheer size of its market for power transmission and distribution, the US is likely to become a major consumer of smart-grid technology in the near future, especially with the integration of renewable sources and electric vehicles. All of these point to a future where the reliability of the smart grid will become paramount. This research program is specifically designed to have a positive impact on the successful development and the evolution of smart-grids, and is likely to have a positive impact on the reliability of other national infrastructures as well. Research materials will be incorporated into the teaching curricula via a new course, and will be disseminated to broad academic and professional audiences. The project will engage PhD and Masters students in research in an area of national importance, and will include outreach efforts to high schools.
