Value of resilience-based solutions on critical infrastructure protection: Comparing with robustness-based solutions

Abstract Additional consideration of recovery rapidity makes resilience-based solutions on critical infrastructure protection conceptually more advantageous than robustness-based solutions, but existing studies have not uncovered how large their differences could be. By considering a pre-event protection strategy frequently adopted both in practice and in the literature, i.e., protecting or retrofitting a set of weak components under a limited budget, this paper introduces four mathematical models and their solution algorithms for exactly identifying the optimal robustness-based and resilience-based protection strategies for critical infrastructure systems against worst-case malicious attacks and natural hazards, respectively. By comparing with the optimal robustness-based protection strategy, the value of resilience-based solution is then quantified by how much the system resilience can be improved and how much the system loss can be mitigated. Taking the electric power transmission system in Shelby County, USA as an example, results show that the optimal resilience-based solutions improve the worst-case system resilience by at most 1.29% and reduce the worst-case system loss by at most 13.25%, and enhance the seismic resilience by at most 0.16% and mitigate the system loss by at most 5.27% under seismic hazards at a 2% probability of being exceeded in 50 years. Other model parameters and several other systems are also investigated.