Assessing the Robustness of Cyber-Physical Power Systems by Considering Wide-Area Protection Functions

With the deepening deployment of information and communication technologies (ICT), the cyber network is playing an increasingly important role in determining the performance of a power system. In this paper, we assess the robustness of cyber-physical power systems and examine various impact factors on the system's robustness. A model that integrates the operating characteristics of the physical network and the wide-area protection functions provided by the cyber network is proposed. Based on the model, cascading failure propagation processes in a cyber-physical power system triggered by initial failures are simulated. Two statistical metrics, the power outage risk and the cumulative power outage size distribution, are then used to quantify the robustness by processing numerous cascading failure simulation results. We conduct case studies on IEEE 57 Bus, IEEE 118 Bus, IEEE 145 Bus, and UIUC 300 Bus with the proposed method. Simulation results demonstrate the necessity to consider cyber coupling, the importance of developing advanced wide-area protection algorithms, and the threat posed by cyberattacks compromising the robustness of cyber-coupled power systems.