Discovering the structure of cascade propagation in power grids

Power systems are often prone to cascade failures, i.e. rapid propagation of failures that start from a set of nodes. Discovery of the pathway that cascade goes through in power systems will give the network planners a realistic insight to predict the extension route of cascade and deter it from expansion before it leads to a catastrophic blackout. In this manuscript we study the mechanism of cascade failures' propagation in power systems. A complex network model is applied to represent power systems where bus bars (generator, loads and transformers) can be considered as nodes and the transmission lines as links connecting these nodes. As benchmark networks we consider IEEE 57 and 118 bus test networks. A maximum flow based model is used to find the central edges. We study the way a cascade is propagated in a power system. We find that at initial steps, the cascade gets propagated locally, but as the cascade proceeds through the network, its pattern changes to a global expansion.