Modelling and Analysis of Availability for Critical Interdependent Infrastructures

The requirement for improving the availability level of critical infrastructures has recently experienced a great increase. In this paper, we propose an availability analysis framework for critical interdependent infrastructures exposed to disruptions caused by equipment failures, cascading errors from neighbouring infrastructures and the damages resulted from natural catastrophes. In this framework, the Muir web network is used to represent the critical infrastructures' interdependencies, and the Markov chain Monte Carlo simulation method is applied to quantitative evaluation of the availability. For the purpose of clearly illustrating the analysis approach, we estimate the availability of an electric power system embedded in the connected fuel and water supplies, and the telecommunication and transportation networks (road, rail, sea, and air) that support its operation. A numerical example illustrates the influence of critical interdependencies on overall availability and provides insights into how to enhance system uptime.