The power generation system is a crucial component of the power system, and reliability analysis of the power generation system is a key step in system design. From the perspectives of capacity models and load models, this study establishes a modeling framework for power generation system and analyzes commonly used reliability evaluation metrics, such as Loss of Load Probability (LOLP) and Expected Energy Not Supplied (EENS), providing a foundation for reliability analysis. The current state of research on power generation system reliability assessment is summarized, offering a reference for the reliability design of power generation systems.