Grey Fox/ Bovay were retained by the Michael DeBakey VA Medical Center in Houston to perform Architectural and Engineering Services for a full Backup Power System to support the 3 million square foot campus facility.
The project required design to provide total backup power using six MW/15kV gas fired generator sets. The campus was served by CenterPoint at the time, with two 35kV, 3 phase utility circuits run overhead on a pole line. From there, both circuits are run underground in a duct bank to four utility 35kV, 3 phase vacuum breakers that feed 35kV-12,470/7,200v, 3 phase pad mounted, and oil-filled transformers.
The MEDVAMC campus is now served and metered at 12,470v, 3 phase. The service conductors, from the CenterPoint yard, are fed underground to an existing pre-fabricated walk-in enclosure with a 6-15kV, 6000A fused breaker section line-up, with access directly outside on the back end. The feeders are then routed underground, beneath the existing paved parking lot to intermediate manholes and to existing main switchgear (MSG) in Building 104, inside the MEDVAMC campus.
The project also required an analysis of the existing one-line diagram and the best option for the electrical interconnection requirements, which are paramount on this project in order to provide the proper phasing without any interruption to the hospital utility services.
Bovay designed a new switchgear building that houses the new 15kV, 3 phase switchgear line-up and six new associated automatic transfer switches. Bovay also planned the proper phasing in order to avoid any electrical down time to the campus.
The critical phasing of the electrical work required making connections from the existing switchgear (normal power) to the new ATS’s (emergency power) and from there to the existing load without having down times. This will entail intercepting the existing underground 15kV feeders running to Building 104 from the existing switchgear. New manholes were placed adjacent to the existing manholes to facilitate their connection to the new feeders from the six new ATS’s. The existing feeder breakers in the existing walk-ins enclosure were disconnected from the load side of the switch and routed to the normal side of the associates ATS. This will be accomplished with the tie-breaker closed in order to ensure there is no down time to the entire distribution system. As a safety factor, temporary back-up generators were also utilized for additional reliability.
The work also included a total environmental approach based on emissions, fuel containment, air intake and outlet of the generator, noise control, site development, structures, underground duct banks, vehicular and pedestrian circulation, open and screened areas, and their relationship to the VAMC campus.