Ensuring a supply of continuous electrical power is vital in critical environments such as hospitals, data centres and commercial institutions where even the shortest interruption may cause significant financial losses or even endanger lives. An Uninterruptible Power Supply (UPS) system is used to provide power when the main source is interrupted or even fails, it also ensures a high level of power quality. Therefore, achieving the highest possible level of availability of a UPS system is of paramount importance.
Availability defines the degree to which a system will continue to operate at any given point in time. The simplest representation of Availability (A) is a ratio of the expected value of the uptime of a system to the aggregate of the expected values of up and down time. In other words, Availability is the most commonly used metric of measurement and is defined as the amount of time a system is operational during its expected lifetime.