Which statement is true about parallel redundant UPS systems?

Parallel redundant UPS (Uninterruptible Power Supply) systems are designed to enhance system reliability and availability by using multiple UPS units working together. The concept of eliminating Single Points of Failure (SPOFs) is central to their design.

When multiple UPS units operate in parallel, if one unit fails, the remaining units continue to support the load without interruption. This redundancy means that there is no single component in the system that, if it fails, would cause the entire system to fail. Therefore, the statement about completely eliminating SPOFs downstream is accurate, as the failure of one unit does not compromise the availability of power to the connected loads.

Considering the other options, not all UPS systems can be produced by any manufacturer for parallel operation without compatibility considerations. Additionally, the assertion that they require the load to always be switched to bypass is misleading—properly designed parallel systems can manage the load without requiring this. Lastly, using units of similar sizes is not necessarily a requirement for parallel operation, although it can be beneficial for load balancing and operational efficiency. These factors outline the validity of the chosen statement regarding the redundancy benefits in UPS systems.