Optimization design on reliability of three-state electrical redundant system

The methods of reliability analysis for parallel-redundant system are different from the traditional two-state system, according to multi-state reliability theory, the design of the three-state electrical parallel-redundant system was optimized, and a mathematical model of the reliable degree for the system was built. The formula of reliable degree was given by an example with usual three-state electrical parallel-redundant system. Researches indicated that it couldn't increase the reliability of the system even adopting the three-state electrical parallel-redundant system with more parallel-redundant branches because of the existence of short circuit failure. On the contrary, it would decrease the reliable degree of system with excessive branches. It differs from two-state system that the optimal redundancy is only 2 for the multi-branch redundancy design with auxiliary contacts of relay which often used in three-state electrical parallel-redundant system. The research results have universality, they are appropriate for electrical parallel-redundant system and the general three-state parallel-redundant system.