Technology for Highly Dependable Large Capacity UPS System

Abstract

Our daily life is supported by powerful information networks which are composed of computers and communication equipments. If they do not work correctly or completely, our daily life would be surely confused. Under some circumstances safety could not be kept. Uninterruptible Power Supply (UPS) systems are commonly equipped to supply stable power to the critical loads, for example, large computer center telephone and telecomnication center, aviation control system and so on. Several kinds of UPS systems are now used in many important fields as the above mentioned. But they almost do not have been evaluated numerically based on system reliability.
This paper evaluates MTBF of parallel redundant UPS systems, and reports MTBF of 2 sets of parallel redundant UPS system is lower than that of 3 sets of parallel redundant UPS system under some circumstances. Continuous power supply reliability of the UPS system with bypass and uninterruptible transfer switch is much higher than any other UPS system without bypass circuit and uninterruptible transfer switch. And then the last some highly reliable parallel operation technology are shown.