Basin Electric's largest substation built to support membership growth

Basin Electric is committed to providing reliable electricity to its members, and this commitment means looking to the future as the membership grows. To meet the expected growth of the membership, construction of a new 19.5-acre substation is underway to replace the 345-kilovolt (kV) substation at Leland Olds Station located near Stanton, North Dakota.

The original scope of the project was to replace the existing Leland Olds Station substation equipment in its current location under a planned Aging Substation Infrastructure Replacement project. The Aging Infrastructure project takes a holistic look at Basin Electric’s aging transmission assets and ranks them according to priority to replace based on many different factors.

As the Aging Infrastructure project progressed, Basin Electric had two new projects that requested to be added at this location. The first project was a Southwest Power Pool (SPP) generator interconnection and the second, the Leland Olds Station-to-Tande 345-kV transmission project, came out of the SPP Integrated Transmission Planning process. These two additions made connecting to the existing substation location problematic as there was limited space to expand.

Without space to expand, alternatives were considered. “After much thought and many internal discussions, Basin Electric made the decision to construct a new Leland Olds 345-kV substation across the highway on land already owned by the cooperative and directly adjacent to many transmission lines making connections convenient,” Derik Johnson, Basin Electric manager of Transmission Systems Maintenance (TSM), says.

The size of the substation is directly correlated to the number of connections coming in and out. The new Leland Olds 345-kV substation will have nine terminals which includes two 345/230-kV transformers, two 345-kV reactors, and room for growth, making it one of the largest 345-kV substations Basin Electric will have. This type of investment in the bulk electric system is required to ensure the cooperative can continue to provide reliable electricity to its members.

Initial work began on the new substation in 2020, with the first few months focused on creating a plan to keep employees and contractors safe throughout construction and commissioning of the new site. Design and engineering of the project also began in early 2020, and material procurement has been ongoing since the beginning of the project as well. Over the course of approximately two years, the Right-of-Way team obtained permitting for the site.

Grading began in the fall of 2022 with the foundations being laid in 2023. “We installed over 700 foundations totaling about 5,000 cubic yards of concrete,” Nate Miller, Basin Electric senior electrical engineer and project coordinator, says. “This allowed us to transition into the general construction phase in November.”

Tyler Bosch, Basin Electric construction coordinator III, oversees and coordinates onsite construction activities at the new substation. “I typically meet with our contractors the afternoon before or first thing in the morning to get an idea of that day’s activities,” he says. “From there it could be anything from overseeing a concrete pour, to inspecting material deliveries, or helping solve issues that arise during construction.”

One of the biggest potential hazards onsite is working under live overhead lines, so the TSM team installed temporary structures at the site to raise the line clearance heights. This way, construction crews could safely work without power line interference before grading of the site could start.

“We’ve had TSM come out multiple times to measure distances to the overhead lines so we can determine how far away we need to stay,” Bosch says. “If we aren’t able to keep our minimum approach distance, we’ll coordinate with TSM to request an outage so we can complete our tasks safely and then get the line back into service.”

With the foundation work completed last summer, crews worked through winter, including the cold weather snap in January when temperatures dipped below freezing for over a week, erecting steel beams and trying to get as much done as they could over the winter months. “We ran with a minimum crew through the winter, but the contractor plans to ramp up to around 15 to 20 contractors on site when we hit peak construction this summer,” Miller says.

Once the steel has been put up and the frost is gone, crews will transition into digging in the underground conduit and grounding. Next steps include moving the transmission lines from one substation to the other. “We are hoping to start cutting over the lines this fall at which point the substation will be energized and operational,” Bosch says. Due to the nature of the substation, both the existing and new substation will be energized during the cutover process.

Bosch says this is by far the biggest substation project he has ever worked on, as the average size of a Basin Electric substation is around 10 acres. “It’s rewarding to be involved in the process from start to finish. When I first started on the project it was a parcel of cropland, and by the end of construction it will be one of the largest substations Basin Electric owns and operates.”

Construction is scheduled to be complete the summer of 2025.