Cyber-physical component ranking for risk sensitivity analysis using betweenness centrality

Abstract

This article proposes a model for critical component ranking in power system risk analysis using a proposed cyber-physical betweenness centrality (CPBC) index. Risk assessment, as part of the contingency analysis, is a critical activity that can identify and evaluate component outages that lead to system vulnerability, aiding operators to improve resilience. A power system cyber-physical risk assessment model is proposed that calculates and offers an efficient protection strategy to the system operator based on component vulnerability to adversaries and the impact of compromised assets on the system operation. We present the CPBC index, which traverses generated attack graphs to rank components according to their importance in reducing adversary impact on the power system. The CPBC extends upon betweenness centrality and integrates into analysis, the services and security cost of communications between system components, as well as the likelihood of component exploitation as an adversary medium to the target relays. The proposed model recommends actions, taking into account the interconnections between cyber and physical components as well as cyber-induced Common Vulnerabilities and Exposure scores associated with these connections, thus protecting critical components. The proposed model is implemented on the Cyber-Physical Situational Awareness 8-substation and extended IEEE 300-bus cyber-physical power system models, and results are presented on the impacts of the proposed component ranking model on the security-aware operation of the power system.