Quantitative and comparative analyses of the reliability of energy arrays

Energy arrays are widely used as a basic part of uninterrupted power-supply systems because they are thought to be more reliable than traditional mechanisms of uninterrupted power-supply sources. In addition, quantitative values of the reliability indices of such devices are absent in the technical literature. It is quite complicated to use the classical methods of assessing the reliability of energy arrays due to unconventional redundancy schemes (load-limited redundancy, hot stand-by). The analysis of failure intensity and restoration (replacement) intensity of the power units as constant values in an energy array results in the validity of the exponential law and provides the possibility to use Markov chains to calculate the device reliability. This article presents a graph of states of an uninterrupted power-supply source, the required mathematical apparatus to calculate the reliability indices, and their quantitative assessment. The calculation results indicate a wide variation of values of the cycle-to-failure, while the availability factor, being the most important indicator of reliability of the restored system, remains quite high.