Testing of Uninterruptible Power Supplies With Nonlinear Loads

摘要

Uninterruptible power supplies (UPSs) are used to provide power to sensitive andcritical loads when the commercial supply has been interrupted. These loads may be nonlinear, which in the military often includes communications equipment, adjustable speed drives, fluorescent lighting, and mainframe and small computers. Most electrical characteristics of UPSs are not currently subject to codes and standards, and there are no military specifications for UPSs. Existing standards assume that UPSs will be operated with linear loads. Since most UPS systems are operated with nonlinear loads, there is concern that UPSs will suffer degraded performance or failure when operated with these loads. This work developed a test methodology by which UPS systems can be tested and their susceptibility to nonlinear loads be quantified. The tests measure load transfer, efficiency, heating, load support, voltage regulation, and isolation. Several commercially available UPS systems are recommended for testing.