Multi-Component Risk Assessment Using Cyber-Physical Betweenness Centrality

Identifying important assets and evaluating the risk they pose to cyber-physical power systems, when compromised, is critical to maintaining the system security and resilience. The cyber-physical betweenness centrality (CPBC) index presents a suitable means for enhancing system resilience through vulnerability analysis and risk assessment. In this paper, we propose and demonstrate the CPBC for the multi-component risk assessment of the cyber-physical power grid. Specifically, the CPBC, based on the concept of betweenness centrality, traverses generated attack graphs to rank important components, while integrating the services, security cost of inter-component communication, and the likelihood of component exploitation as an adversary medium to the target relays. The CPBC index notably categorizes components in the same security caliber, hence simplifying computation for the system operator. The proposed model is implemented on the Cyber-Physical Situational Awareness 8-substation cyber-physical power system model and results demonstrate to the power system operator, the combinations of components to which security resources should be allocated.