  The reliability of electric transmission systems is examined using a
scale-free model of network structure and failure propagation. The topologies
of the North American eastern and western electric networks are analyzed to
estimate their reliability based on the Barabasi-Albert network model. A
commonly used power system reliability index is computed using a simple failure
propagation model. The results are compared to the values of power system
reliability indices previously obtained using standard power system reliability
analysis methods, and they suggest that scale-free network models are useful
for estimating aggregate electric network reliability.
