Running two or more UPS in parallel (and thus configuring a parallel UPS system) enables customers to either add redundancy or greater capacity. There are, therefore, two primary types of parallel UPS
parallel redundancy and parallel capacity UPS
In a parallel UPS system, the keys are:
• Controlling how the separate UPS ‘co-operate’ as one unified system.
• Synchronizing the output of each UPS so it can flow into a shared output.
• Balancing the load equally amongst all UPS in the configuration.
• And if a problem occurs, identifying the UPS with the problem and decommissioning it
The advantages of a parallel redundant UPS system are that if offers a far higher level of availability than parallel-capacity systems due to the extra capacity within each UPS module.
This can be utilised if one breaks down or has to be taken out of service for maintenance. The system is also less likely to fail than other parallel configurations because there are fewer breakers and no step loads (modules are online the whole time). It is also expandable should the power requirement grow and the hardware arrangement is simple and cost-effective.