What are Uninterruptible Power Supplies (UPS) Parallel Systems ?
This type of system comprises two or more UPS modules that operate together to feed a common critical load bus. This means that you can increase the overall capacity to support more load and / or provide additional redundancy, whereby if one UPS fails you still have the other units to back up the load.
Units forming part of such a multi-module system are identical in operation to that of their corresponding single module counterparts. In fact, manufacturers design their UPS modules such that they can be used in either configuration without the need for complex modification.
There are two major reasons for installing a parallel system. The first is to increase the effective UPS capacity to enable the ‘system’ to power a larger load than is otherwise possible with single module. The second is to introduce a measure of module redundancy to improve the anticipated system reliability. Parallel UPS systems are therefore commonly categorised as either ‘capacity’ or ‘redundancy’ systems, although some are intelligent enough to operate as either, depending on the prevailing circumstances.
Irrespective of the intended mode, all the modules forming part of a parallel system must be of the same type and rating – i.e. it is not possible to parallel a 30kVA unit with a 120kVA.
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