Misc,
Reducing Cascading Failure Risk by Increasing Infrastructure Network Interdependency
(Oct 24, 2014)
Abstract
Increased coupling between critical infrastructure networks, such as power
and communications, has important implications for the reliability and security
of these networks. To understand the implications of power-communications
coupling, researchers have studied interdependent network models and reported
that increased coupling can increase system vulnerability 1, 2. However,
these results come from models that have substantially different mechanisms of
cascading, relative to those found in actual power and communications networks.
This paper reports on two sets of experiments that compare the network
vulnerability implications resulting from simple topological models and models
that more accurately capture the dynamics of cascading in power systems. In the
first set of experiments, we compare a simple model of intra-network cascading
to a power grid model and find that the power grid model reveals that power
grids have a higher level of vulnerability, relative to what would be inferred
from a topological contagion model. In a second set of experiments, we compare
the coupled topological model from 1 to three different physics-based models
of power grids coupled to communication networks. Again, the results show that
more accurate models lead to very different conclusions. In all but the most
extreme case, the physics-based power grid models suggest that increased
power-communications coupling decreases vulnerability. This is opposite from
what one would conclude from the model in 1, in which zero coupling is
optimal. Finally, an extreme case, in which communications failures immediately
cause grid failures, suggests that if systems are poorly designed, increased
coupling can be harmful.
