A robustness metric for cascading failures by targeted attacks in power networks

Cascading failures are the main reason blackouts occur in power networks. The economic cost of such failures is in the order of tens of billion dollars annually. In a power network, the cascading failure phenomenon is related to both topological properties (number and types of buses, density of transmission lines and interconnection of components) and flow dynamics (load distribution and loading level). Existing studies most often focus on network topology, and not on flow dynamics. This paper proposes a new metric to assess power network robustness with respect to cascading failures, in particular for cascading effects due to line overloads and caused by targeted attacks. The metric takes both the effect of topological features and the effect of flow dynamics on network robustness into account, using an entropy-based approach. Experimental verification shows that the proposed robustness metric quantifies a power grid robustness with respect to cascading failures.