Continuous Markov-Based Reliability Analysis of Underground Vault in Distribution Power Systems

This paper presents a reliability analysis of an underground vault system (UVS) designed for distribution substations using continuous Markov process. Given that underground vaults are exposed to diverse weather conditions affecting system performance and aging, a comprehensive reliability analysis becomes crucial. In distribution system UVS consists five major subsystems, i.e. Transformer, Circuit Breakers, Sensors, and Bus Bars. A Markov-based sixteen state transition matrix developed for the UVS is solved in Matlab environment to identify the state probabilities and overall reliability. The UVS reliability is found as 77.66 % on its 20 years of operational period utilizing four subsystems' failure and repair rates.