Critical node analysis (CNA) in power grids under enhanced restoration options

In recovering from cyber attacks on power grids, restoration steps have also included disconnecting parts of the network to prevent failures from propagating. Inspired by these reports we investigate how this may be performed optimally. We show how throughput can indeed be increased by selectively disconnecting links when the network is currently stressed and unable to meet all of the demands. We also consider the impact of this option on critical node analysis. For defensive as well as offensive scenario planning it is important to be able to identify the critical nodes in a given network. We show how ignoring this option of disconnecting links can lead to misidentifying critical nodes, overstating the impact of these nodes. We outline an iterative procedure to address this problem and correctly identify critical nodes when link disconnection is included in the recovery scheme.