S.W. Minnesota Wind Transmission Upgrade

S.W. Minnesota Wind Transmission Upgrade

Client: Xcel Energy

Completion Date: 2008

Burns & McDonnell was selected by Xcel Energy as the engineer-procure-construct (EPC) contractor for its Southwest Minnesota Wind Transmission Upgrade Project. The project consists of 86 miles of 345-kV and 39 miles of 115-kV transmission lines plus two new and two retrofit substations.

  • Transmission line construction
  • Substation construction
  • Right-of-way acquisition
  • Permitting
  • Transmission line and substation design
  • Procurement

Burns & McDonnell acted as EPC contractor for this project. Included in the EPC scope was right-of-way (ROW) acquisition; procurement of all structures, assemblies, conductor, substation steel, equipment and protection; detailed design; construction management; construction; permitting; and overall management.

Burns & McDonnell subcontracted ROW acquisition, construction, surveying, geotechnical investigation, and testing services. All other services are self-performed, including transmission and substation design, permitting, construction management, procurement, scheduling and cost control.

The 345-kV transmission line includes single circuit and double circuit configurations. The structures are monopole on drilled pier foundations. The double circuit sections include 161-, 115- and 69-kV lines requiring close coordination with other area utilities.

The 115-kV transmission line includes single and double circuit configurations with sections of single and double circuit underbuild. Double circuit sections include 24-, 69- and 115-kV construction. Underbuild is 34.5-kV consisting of local wind farm collection circuits.

The 345-kV line originates east of Sioux Falls, S.D., at Split Rock Substation and is generally routed east paralleling I-90 to Lakefield Junction in Minnesota. The 115-kV line originates near Worthington at a new substation and is routed northeast to an existing substation, Chanarambie, west of Lake Wilson City.

Near our field office in Worthington, Minn., is the larger of the two substations, Nobles Substation, a 345/115-kV substation with a 672MVA autotransformer. The Split Rock and Lakefield Junction lines connect at Nobles. The 115-kV line leaves to the north to a new substation, Fenton.

The Fenton Substation is roughly halfway between Nobles and Chanarambie substations. Like Chanarambie, Fenton Substation is a wind farm collector station. The substation consists of two 170 MVA 115/34.5-kV transformers.

Chanarambie Substation was expanded to accept the new 115-kV transmission line. Split Rock Substation will be expanded to accept the new 345-kV transmission line.

Burns & McDonnell employed a sizable field staff for the project, including a site manager, multiple discipline superintendents, a safety lead, a schedule controller and other administrative staff.

  • Single and double circuit 345-kV transmission lines
    • Split Rock to Lakefield Junction
    • Parallel to I-90 and cross-country
    • ROW acquisition
  • New Nobles County 345/115-kV bulk transmission substation
    • Autotransformer
    • Shunt reactors and capacitor banks
  • Single and double circuit 115-kV transmission lines
    • Nobles County to Chanarambie
    • Parallel to county and township roads
    • ROW acquisition
  • New Fenton 115/34.5-kV wind farm collector substation
    • Underground cable entry
  • Retrofit of 345-kV Split Rock Substation
    • Expand ring bus and add line position
  • Retrofit of 115-kV Chanarambie Substation
    • Add line position