This is a project to investigate the robustness of the US power transmissions grid. You can think of it as a bidirectional vertex-edge graph, where transmission lines are edges, and infrastructure such as their connections, power plants or transformers are nodes. Given this representation, you could determine which line(s) are most crucial in the sense that there are relatively few alterative paths in case the line(s) goes down.
Transmission lines from the US Energy Atlas