The Levee Feeder Upgrade at Scott Air Force Base (SAFB) involved a substantial change in the mode of electrical power distribution at the base, moving power lines from traditional overhead poles to an in-ground, concrete reinforced duct bank. The net advantage is the reduction of vulnerability to violent weather and other hazards, along with increased “hardening” of infrastructure, always welcome at a strategic US military base. Additionally, the project called for the replacement of a 23 y/o 35 kV Switchgear that was in need of some substantial maintenance with a state-of-the-technology, five (5) section distribution gear. The new equipment’s modular design offers the added benefit of simplifying the provisioning of power as well as electrical systems maintenance serving buildings across the western half of the base.
In all, GECO Illinois installed two miles of underground conduit, together with a similar volume of medium voltage cabling. To realize the design, GECO also installed eight prefabricated manholes to effect the necessary wire pulls through the duct bank system. Ultimately, these will provide access as well for any subsequent maintenance to the distribution. To manage passage of the duct bank across roads and other potential barriers without tearing up roads and other surface assets, four (4) underground bores were conducted.
Outages required for testing and final cutover to the new switchgear and cabling system, called for extensive planning to coordinate excavations, moving and replacement of three overhead poles, as well as the installation of equipment, demolition and concrete work entailed directing multiple crews: overhead linemen, crane operators as well as GECO Illinois craftsmen performing terminations and testing, etc.
The unique requirements of working on a military base, involved GECO’s in close coordination of outages, etc. with key personnel of the 375th Civil Engineering Squadron responsible for maintaining SAFB facilities. The effort necessitated layers of preplanning and schedule management on the base that generally calls for a 30 day window for planning such activity. Outage management also required coordination with Ameren Illinois, as well nearby lines of the BNSF Railroad.
- GECO Illinois excavated, and installed one-half mile of in-ground, concrete encased duct bank containing roughly two miles of zero-inch conduit containing medium voltage cabling
- Installation logistics required four (4) underground bores, with the excavation and placement of 8 pre-fabricated manholes at 250 – 300 foot intervals, providing wire-pull and future maintenance access
- The Levee Feeder implementation required replacing the existing Switchgear with an advanced 600 Amp. 34,500 Volt gear with five sections supplying a more manageable 20 million watts of medium voltage power to the base
The Levee Feeder Upgrade project at Scott Air Force Base was completed on budget well within the augmented schedule necessitated by factors necessitated by the Air Force. For its size and for the improvements in performance and reliability delivered, completing the project within a budget under a million was a notable accomplishment. This was further enhanced by the fact that work was completed with zero recordable lost time injuries.