The Power system design normally provides function effectively to the consumers. Therefore the interruptions cannot be avoided which cause power unavailability which affect the generation of electricity for high quality achievement. This research paper analyzes the reliability system of Karu substation in Abuja for proper system planning and design in the power network using network reduction and analytical method. The analysis was done using MATLAB 2015 software. The paper analysis shows that overloading and transformer failure are the most unavailable to the substation. Finally the total reliability analysis of the distribution system showed that the substation performance is poor with 88.46% compare with the standard benchmark