Defense Information Systems Agency Building 200, Electrical Capacity Upgrade

Building 200 houses the DISA San Antonio datacenter located at 3326 General Hudnell, San Antonio, Texas, including the electrical and mechanical infrastructure elements, raised floor areas and security systems to provide continuous 24 hour operations. As part of the electrical infrastructure, the building has two electrical power feeds delivering utility power to the facility. The power is delivered at 13.2kV, through a 2,500kVA transformer stepping it down to 480V. Each transformer feeds a walk-in utility switchgear enclosure rated at 3,200Amps. Each utility enclosure contains several breakers. These walk-in utility enclosures are labeled as Utility Bus ‘A' and Utility Bus ‘B'. Each Utility Bus has an output breaker feeding the ‘A' and ‘B' bus Essential Distribution Switchgear. The Essential Distribution Switchgear contains breakers that supply power to the ‘A' Bus and ‘B' Bus UPS Modules, Static Bypass Switches and Maintenance Bypass Switches. The UPS system is set up in a 2(N+1) redundancy, such that either side can be shut down while still maintaining power to all critical equipment. The Essential Distribution Switchgear ‘A' and Essential Distribution Switchgear ‘B' also supply all non-UPS loads including all essential cooling equipment system components (pumps, valves, chillers, cooling towers, etc), lighting, and general building power.

Both utility enclosures are supported by the generator back-up power system which automatically transfers both substations to generator power in the event of a commercial power loss. The generator system consists of three (3) Caterpillar 3512 diesel/generator sets rated at 1875kVA/1500kW each, and a full set of generator paralleling switchgear. System is designed for a load of 3750kW with N+1 redundancy. This switchgear cabinet contains the generator tie breakers which feed each of the substation generator breakers. It also houses the paralleling and transfer operations logic and control systems. The generators and switchgear were installed in 2009. A building load test in performed monthly with a simulated utility loss test. The majority of the essential systems components are installed in redundant pairs. The facility is equipped with two 700 ton chillers, two chilled water pumps, two condenser water pumps, and two cooling towers. Only one chiller paired with associated cooling tower and one of each pump is required to meet the facility cooling demands.

The Contractor shall segregate the facilities mechanical loads from the critical loads. Currently, the mechanical loads and the critical loads are fed from same the Essential Distribution Switchgear. In order to segregate the mechanical loads from the critical loads (UPS), new UPS distribution switchgear, 2ea new UPS modules will be added and 2ea existing UPS modules will be removed. The existing UPS modules and the new UPS modules will be fed from new Critical Distribution Switchgear including the installation of two new utility transformers to feed the new Critical Distribution Switchgear. The existing mechanical loads will remain being fed from the Essential Distribution Switchgear. The project will also include the addition of one new emergency generator, new generator paralleling switchgear to support the existing generators (3ea) and new generator (1ea) and a new generator control panel. This will result in a more robust and reliable electrical and mechanical distribution system. This system shall allow for an automatic or user initiated closed transition from generators to utility and automatic transition from utility to generators upon commercial power failure. In addition to the new Critical Distribution Switchgear, new UPS Output Critical Distribution Switchboards (2ea) will be installed to feed critical loads in multiple computer rooms.