Nov. 3rd, 2011 - 2.30 pm
Building E - Room 1

Hélène Grandclaude - CEA Saclay, Paris

The failure of a single element in systems such as electrical networks may lead the whole network to large blackouts. A simple load-redistribution model was proposed by Lehmann& Bernasconi to grasp the main underlying characteristics of the failure propagation. By means of an analogy with a generalized branching process, we obtain analytical and numerical results.
These results show the existence of two transition thresholds between a phase where no global cascades are possible and a phase where they occur with finite probability. We explore the properties of the cascade in this simple formalism and show that the two thresholds behave differently. I will explain these transitions, and show how the key quantities are changed.