Beale Air Force Base (AFB) is a located in Marysville, California. The host unit at this AFB is the 9th Reconnaissance Wing which is assigned to the Air Combat Command and that is composed of over 3,000 personnel divided into four groups spread in various detachments.
Beale AFB examined the existing power distribution system configuration, electrical loads and projected future load growth and determined that the base need power reliability against blackouts. Taking this study into consideration, it was necessary to install a Static Uninterruptible Power Supply (SUPS) system on Building 5771 located inside the base.
RBT Electric, Inc. developed a complete proposal to Beale AFB and was selected to install two (2) parallel Powerware 9355 30/20 kVA SUPS Modules rated at 20kVA / 18kW (0.9 pf), each one of them with 18 minutes of battery back-up to supply 20 kVA existing and future electric loads of the building against blackouts.
During the site inspection, the RBT team developed a scheme of the electrical installation which consisted of two (2) power transformers of 3 MVA, 4.16kV: 208/120V that were fed through two (2) Main switchboards that also fed the two (2) existing 50/40kVA UPS modules. Then, these UPS modules fed main breakers of the Critical Distribution Panel (CDP).
Based on the installation requirements, RBT Electric, Inc. disconnected one of the existing UPS units to allow the installation of the new SUPS modules and also installed a new Maintenance Bypass Panel (MBP) with equipment of a minimum interrupt current rating of 14.5 kA for isolation of both UPS modules during normal operation. This avoided the need to drop the critical load as it was previously established in the installation.
Environmental and heat studies were also performed in the installation to guarantee the perfect operation of all SUPS modules Beale AFB which were also installed in accordance with the National Electric Code, Uniform Building Code and Federal codes.