Abstract

Critical National Infrastructure (CNI) provides essential services to society; therefore, any dis-
ruption can have catastrophic consequences for the public and pose significant threats to national
security. Among the various elements of CNI, the power grid serves as the backbone of the en-
ergy infrastructure and holds critical importance, as the functionality of other CNIs heavily depends
on its reliable and secure operation. In this regard, Information and Communication Technologies (ICTs) have been widely integrated into power grids to enable more rigorous monitoring and expedite essential responses to disturbances. This incorporation results in improved service quality, increased reliability, and enhanced resilience. Extensive utilization of ICTs, however, can increase
the risk of cyberattacks against the smart grid. Such attacks can adversely affect the operation of the power delivery system and noticeably degrade its resilience, as evidenced by real-life cyberattacks. To strengthen the resilience of the smart grid against cyberattacks, it is essential to first evaluate its resilience posture. Accordingly, this research aims to develop a quantitative framework for assessing the resilience of the smart grid as a cyber-physical system. The most common resilience paradigm defines resilience through five key phases: preparation, survival, sustainment, recovery, and adaptation. Through this thesis, we provide several innovative solutions across four distinct contributions for assessing the resilience of the smart grid in various phases. In the first contribution, we assess resilience during the preparation phase and explore ways to enhance it. Specifically, we assess the resilience of an islanded microgrid and enhance it through the optimal allocation
of distributed energy resources and diversification of Intelligent Electronic Device (IED) vendors during the design stage. In the operational phase, prior to any cyberattacks, we implement power
system reconfiguration to strengthen preparedness. In the second contribution, we propose a metric for quantifying the resilience of the smart grid during the survival phase within the transmission
domain. This approach is applied to cyberattacks targeting IEC 61850-based substations, focusing on attacks detected in the Industrial Control System (ICS) environment. The proposed solution addresses untrusted data from compromised substations and provides confidence in the results. For the third contribution, we investigate the resilience of substations with a focus on attacks detected in the Regional Control Centre (RCC) environment. We derive three metrics to provide the system’s resilience level, the probability of attack success, and the remaining time before the attack’s final execution. Finally, as the fourth contribution, we introduce a quantitative approach for assessing and enhancing the resilience of the smart grid during the recovery phase within the transmission domain.