Remember, PowerContinuity Means Business Continuity. To ensure that failure is not an option, always take into consideration: is your power protected? If not, what steps should you take to ensure that it is?
This type of system comprises two or more UPS modules sometimes referred to operating in parallel to feed a common critical load bus, and is generally applicable to medium/high rated modules of on-line design. Units forming part of such a multi-module system are almost identical in operation to that of their corresponding single module counterparts. In fact, some manufacturers deign their UPS modules such that they can be used in either configuration without the need for complex modification. Each module contains a static switch to provide a means of transferring the load between inverter and bypass. However, a certain amount of inter-module electronic control logic is added to ensure that all the module's static switches operate simultaneously when transferring from one power source to the other. Damage would result if one module attempted to transfer its output to the bypass line which the others remained on inverter. Additional inverter control functionality is also required to facilitate inter-module load sharing and frequency synchronisation. These control signals, and others, are passed between the modules over low voltage control cables which are normally connected in a ring configuration to allow each module to communicate with every other module in the system. One advantage of providing external input and output isolators for each of the modules is that it allows modules to be fully isolated and 'hot-swapped' if necessary without disrupting the remainder of the system. 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 that 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 one of 120kVA. For further information regarding our range of uninterruptible power supplies, such as diesel generators please visit our website.
Uninterruptible Power Supplies - What are UPS Parallel Systems?
