An entropy-based metric to quantify the robustness of power grids against cascading failures

• We model cascading effects in power grids by using complex systems theory.
• We propose a new metric to quantify the robustness of power networks against cascading failures.
• The metric incorporates information about both the topology as well as the operative state of the grid.
• The metric is applied to different power grids which gives new insight in the dynamic nature of their robustness.
• This newly acquired insight can be used to optimise and enhance the robustness of power grids.

The cascading failure phenomenon in a power grid is related to both the structural aspects (number and types of buses, density of transmission lines and interconnection of components), and the operative state (flow distribution and demand level). Existing studies most often focus on structural aspects, and not on operative states. 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 under targeted attacks. The metric takes both the effect of structural aspects and the effect of the operative state on network robustness into account, using an entropy-based approach. IEEE test systems and real world UCTE networks are used to demonstrate the applicability of this robustness metric.