The basic mathematical method for power system reliability evaluation was indicated, the simple and complex system was respectively introduced, several methods of reliability analysis of simple was given in this paper, and the reliability evaluation indexes system and methods of composite generation and transmission system was analyzed, then focused on state enumeration method applied in the reliability assessment of system, the detailed example analysis was given and the adequacy reliability indexes were computed in detail. Finally, the current reliability evaluation and status of composite generation and transmission system was summarized simply and its reliability evaluation algorithm steps applied in current actual engineering projects was given.
