Reducing Cascading Failure Risk by Increasing Infrastructure Network Interdependence

Abstract

Increased interconnection between critical infrastructure networks, such as electric power and communications systems, has important implications for infrastructure reliability and security. Others have shown that increased coupling between networks that are vulnerable to internetwork cascading failures can increase vulnerability. However, the mechanisms of cascading in these models differ from those in real systems and such models disregard new functions enabled by coupling, such as intelligent control during a cascade. This paper compares the robustness of simple topological network models to models that more accurately reflect the dynamics of cascading in a particular case of coupled infrastructures. First, we compare a topological contagion model to a power grid model. Second, we compare a percolation model of internetwork cascading to three models of interdependent power-communication systems. In both comparisons, the more detailed models suggest substantially different conclusions, relative to the simpler topological models. In all but the most extreme case, our model of a “smart” power network coupled to a communication system suggests that increased power-communication coupling decreases vulnerability, in contrast to the percolation model. Together, these results suggest that robustness can be enhanced by interconnecting networks with complementary capabilities if modes of internetwork failure propagation are constrained.

The key player problem in complex oscillator networks and electric power grids: Resistance centralities identify local vulnerabilities

“…Pure or partially extended graph theoretic methods have been applied in vulnerability investigations of electric power grids [19][20][21], and investigations of cascades of failures in coupled communication and electric power networks [22,23]. They have however been partially or totally invalidated by investigations on more precise models of electric power transmission that take fundamental physical laws into account (in this case, Ohm's and Kirchhoff's laws) [24,25].…”

Limits of Predictability of Cascading Overload Failures in Spatially-Embedded Networks with Distributed Flows

“…Note that despite the simplicity of this fundamental model for conserved flows (i.e. Kirchhoff's and Ohm's law in the resistor network), the underlying system of equations have identical structure to those of the DC power-flow approximation (the current and voltage corresponding to the power and phase, respectively) [4,10,34].…”

Risk of Cascading Blackouts Given Correlated Component Outages

“…The method will also be applied to study the risk of cascading failure in interdependent networks, which are ubiquitous in human-engineered infrastructures [47]. For example, coupling between communication and power networks can substantially impact their robustness to cascading failures [48], [49]; the method presented herein could help to quantify the impact of this coupling on risk in the presence of correlated component outages. As new methods for measuring the risk of cascading failure in systems with correlated initiating event probabilities emerge, there will be a need for comparisons to better understand the relative computational efficiency and accuracy of these approaches.…”