Power System Equipment Cyber-Physical Risk Assessment Based on Architecture and Critical Clearing Time

Abstract

With the trend of constructing Internet protocol (IP)-based systems, modern power grids are involving into integrated networks made up of cyber and physical infrastructure with the goal of improving stability, reliability, and efficiency. Cyber technology is the backbone of modern power grid operation, yet vulnerabilities in the cyber network can introduce cyber-enabled disruption of physical components, which may lead catastrophic outcomes. Thus, cyber-physical equipment assessment is needed for modern power grids to better prepare against unexpected contingencies. In this paper, the digital relay is representative of cyber-physical equipment in power grids since it is a connector between the cyber network and the physical infrastructure. This paper presents two methods to evaluate cyber-physical risk of all digital relays in a power system. These methods are based on cyber-physical architecture and critical clearing time respectively. The analysis is conducted on an 8-substation model with its cyber network and cyber-physical architecture. The ranks of each digital relay provide useful information for situational awareness in modern power grids. An online framework that evaluates cyber-physical assets in power systems from these two perspectives is presented.