Availability Analysis of a Redundant System with Common-Cause Failure

In order to analyze the availability of a redundant system with common-cause failure (CCF), a developed availability model was proposed in this article, which assumed that several components or the whole system would fail to perform its function if a CCF occurs. Markov method was used to describe the model. And this article probed into the calculation method on availability index and obtained its numerical solutions. For illustration, an electric sources example which is a 2/3(G) system actually was utilized to show the effect of redundancy and CCF. The results showed that the availability of redundant system was higher than that of the system without any redundancy. Moreover, availability of redundant system without CCF worked better compared with that with CCF. Availability modeling by Markov method for redundant system with CCF was more convincible than that without CCF. And it showed that CCF had non-negligible adverse influence on availability.