China has formed a large-scale gas pipeline network across the country to ensure reliable supply of clean energy. However, due to the external interference, the quality defects, equipment failure and unsafe operation, the safety and reliable supply of pipelines become a significant challenge to the pipeline industry.

A straightforward way to solve the problem would be identifying and quantifying the reliability of the pipeline system first, then finding the weakest point of the system and strengthening it thereafter. But calculating the reliability of a pipeline system is very complicated and lies in non-linearity between the reliability of the system and that of its components.

To obtain the reliability, an entirely new approach which combines Bayesian theory and “N-1”principles is firstly presented. With Bayesian theory, the entire possible situation is included in the math formula, however, to avoid extensive computational cost and data requirements, the “N-1”principles are adopted. With the new presented method, the reliability for a single trunk pipeline is calculated and the results show a distinct coincidence with the industry data.

With the new approach, the reliability for any single gas transmission pipeline can be obtained; hence it could provide the fundamentals for the reliability calculation of the gas network and identification for the weakest point of the system.