Uninterruptible power supplies (UPS) are critical elements of infrastructure in the power distribution system of a data center, and as such they must remain stable as the scale of the data center grows to several MW. In the past, Facebook has experienced data center power system instability as discussed at the Open Compute Project Data Center Facility Project Call [https://www.youtube.com/watch?v=aUk_-ufhR2Y&feature=youtu.be].
The objective of this paper is to show the analytical process to establish system specifications for UPS systems to remain stable within large scale data centers, which are characterized by having a large number of regulated power supply units as rack loads. Existing UPS standards specifying performance and test requirements do not consider operation with regulated power supply units. For illustrative purposes, representative case studies are proposed and simulated in a computer program to verify the stability predictions from our analytical framework.
In the draft paper, only the bypass mode is covered, but the final paper due on Dec. 18th, 2019 will cover the other typical UPS operating modes.