- Southwest Minnesota Wind Transmission Line Upgrade
Burns & McDonnell was selected by Xcel Energy as the engineer-procure-construct (EPC) contractor for their Southwest Minnesota Wind Transmission Upgrade Project (SWTU). The project consists of 86 miles of 345-kV and 39 miles of 115-kV transmission lines plus two new and two retrofit substations.
The EPC scope included 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 were self-performed including transmission and substation design, permitting, construction management, procurement, scheduling, and cost control.
The 345-kV transmission line included single circuit and double circuit configurations. The structures are monopole on drilled pier foundations. The double circuit sections include 161-kV, 115-kV, and 69-kV lines requiring close coordination with other area utilities. The 345-kV line originates east of Sioux Falls, South Dakota 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.
The 115-kV transmission line also included single and double circuit configurations. Double circuit sections include 24-kV, 69-kV, and 115-kV construction.
Near our field office in Worthington, Minnesota is the larger of the two substations, Nobles Substation. This substation is a 345/115/34.5-kV substation with a 672MVA 345/115-kV autotransformer and a 170MVA 115/34.5-kV transformer for wind farm collection. 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 and Nobles, 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.
- Transmission line construction
- Substation construction
- Right-of-way acquisition
- Transmission line and substation design
Due to the continued population growth and the proliferation of wind power in the Sioux Falls area of southeast South Dakota and southern Minnesota, Northern States Power, dba Xcel Energy, decided that two new transmission lines and two new substations were needed to increase the supply of electricity throughout Southern Minnesota.
Through the Minnesota and South Dakota Public Utility Commissions, Xcel Energy requested and was granted permission to construct the two Transmission lines along with two new substations to capture the power produced by several new wind generation projects and enable Xcel to use and export the power to other areas of the state. This project increased the electric reliability of the power grid in the upper Midwest and provided an outlet for the power produced by those wind turbine farms that continue to sprout up in this geographically windy area.
This project ties together several substations in southern Minnesota which will provide continued outlets for wind power projects of the future, as well as fuel the continued growth in population in the rural areas and small towns along the I-90 corridor.