The purpose of this thesis is to identify the vulnerabilities of the power system to ensure its robustness and resilience. Like any other critical infrastructure (CI), power systems are subject to disruptions, either unintentional or deliberate, that may have a significant impact on their performance. Hence, to protect and mitigate such vulnerabilities when CIs suffered from an event, first, one has to explore advanced tools for modeling the electric power grid and its components with respect to its vulnerability to disruptions. Then, trying to guarantee the correct flow of electricity from generation facilities to consumers using appropriate countermeasures. The focus of the present thesis is on modeling, simulation, and optimization of the power systems with respect to their vulnerability to disruptions and hazards. The outcomes of our research can provide valuable inputs and tools of analysis to public and private decision-makers and system operators.