Power system configuration uninterruptible power supply

Uninterruptible power supply (UPS) systems are used to provide uninterrupted, reliable, and high quality power for these sensitive loads. Applications of UPS systems include medical facilities, life supporting systems, data storage and computer systems, emergency equipment, telecommunications, industrial processing, and on-line management systems.

The standalone configuration (Figure 1), is the most common configuration utilized in UPS applications because it contains fewest number of major components. This system utilizes AC power (typically utility power) and converts it to DC through the rectifier. The regulated DC power is supplied to both bank of batteries and to the inverter.

For large power supplies, a dynamic uninterruptible power supply (DUPS) can be used. The synchronous motor/alternator is connected to the mains power supply through a choke. Flywheel stored the energy. In the event of a line failure, the stored current control keeps the load driven until the power of the flywheel is exhausted.

Over the years UPS designers have come up with ways to harness maximum power capacity within a finite space. This is often achieved by scaling the number of UPS systems in a configuration to cope with the; load requirement, budget, existing infrastructure and risk tolerance.

Uninterruptible Power Supply (UPS) configurations significantly impact data centre reliability and resilience. This white paper examines five key UPS designs: capacity (N), isolated redundant, parallel redundant (N+1), distributed redundant, and system plus system (2N).

Conventionally, reliability parameters of the DC uninterruptible power systems are presented by using the state-space method [ 2 ]. In this approach, firstly, all the possible system states have to be identified. Then, the state-transition diagram has to be constructed in order to show the interdependencies between the states.