Xcel Energy makes way for Denver stormwater system
DENVER, Colo. (April 23, 2019) ‒ Xcel Energy overcame short outage windows, a seemingly impossible deadline and a complex cutover to relocate two underground transmission lines and make way for the largest stormwater project in Denver’s history.
Denver expects to complete the stormwater channel project to relieve frequent flooding in the city’s historic north and northeast neighborhoods by later this year. The stormwater problem area is in the Montclair basin, the largest basin in Denver without sufficient drainage for stormwater to get to the South Platte River.
For the huge stormwater project to move ahead in summer 2018, Denver called on Xcel Energy to first relocate two 115 kV high-pressure, fluid-filled (HPFF) underground transmission lines out of the path of the drainage channel. Among additional challenges the utility had to meet:
- Perform complex engineering design in four months
- Design a route along crowded and historic business and residential streets
- Design and build termination structures in tight substation spaces
- Adapt the design to accommodate undocumented underground utilities and other historic surprises
To help with the successful completion of this project, Xcel Energy hired POWER Engineers Incorporated (POWER) to design the two lines in phases and move the designs into construction as crews completed each phase.
“Open communication, careful scheduling, coordination, and construction meetings with the city, Xcel Energy crews, POWER and contractors kept the project moving ahead in a timely manner,” said Adam Smith, POWER’s design engineer for the project.
This close working relationship paid off when crews encountered abandoned or undocumented utilities beneath streets in historic neighborhoods. The route couldn’t be changed because of the tight schedule, so POWER created efficient underground designs around these obstacles.
POWER brought extensive experience with underground transmission projects and solving tough project challenges to this effort. This includes meeting fast-track schedules and situations requiring innovative solutions such as an undersea cable for the first U.S. offshore wind farm and the country’s longest 345 kV XLPE cable installation within a directional bore.