Ensuring reliability: Aging substation infrastructure replacement initiative continues to make progress

Everything is subject to the effects of aging, even substation infrastructure. Having been installed in the 1970s and 80s, some of Basin Electric’s infrastructure is over 50 years old, and like most things, parts wear out and things break down. As new technology emerges it’s critical to the lifespan of a substation to upgrade equipment before there’s a problem. Without upgrades, aging infrastructure will begin to fail, which could affect reliability.

To prevent this from happening, Basin Electric implemented the Aging Substation Infrastructure Replacement Initiative in 2018 as the cooperative’s approach to strengthen and modernize its infrastructure and help ensure reliability for the cooperative’s members. The cooperative is on track to complete upgrades to several substations by 2025.

“In general, a good portion of our substation infrastructure has a life expectancy of 40 years or more. Some of the communications and relaying systems require replacement more often,” says Derik Johnson, Basin Electric manager of Transmission System Maintenance. “Every spring, we evaluate our 10-year capital replacement plan called the long-range engineering plan. During this process we work with Basin Electric’s Engineering, Transmission, and financial services teams to identify schedule changes or new projects.”

These teams work hard to be proactive in replacing aging infrastructure before the equipment fails since an unscheduled replacement generally costs more and doesn’t fit well with an overall planned replacement.

In support of the initiative, with the Engineering team leading the coordination efforts, a cross-functional team was developed to create a ranking system to help identify infrastructure most in need of equipment replacement. Ranking was based on age, test data, and the availability of manufacturers that could support aging substation equipment.

“As equipment ages, spare parts often become unavailable or difficult to locate, which may result in longer outages for repairs. Thus, upgrading equipment and components helps to improve transmission system reliability by decreasing the chances of equipment failures, mis-operations, and extended outages due to a lack of spare parts,” says Chad Kuntz, Basin electric supervisor of Electrical Engineering. A timeline was created and projects were spaced far enough apart to ensure available resources.

Still, global supply chain issues have impacted the lead times and availability of material and equipment. “There are many examples of equipment lead times doubling, which can add 6-18 months to project timelines depending on equipment needed,” Kuntz says. “This has caused Engineering to reevaluate the initiative’s project schedules, as well as work with Procurement to coordinate purchases to support project timelines.”

Since the start of the initiative, several projects have been completed or are nearly complete including:

• Rapid City (South Dakota) DC Tie control system
• Pahoja substation in Iowa
• Antelope Valley Station-to-Broadland 345-kilovolt
(kV) terminal at Antelope Valley Station 345-kV
substation in North Dakota
• Broadland 345-kV substation in South Dakota
• Laramie River Station 230-kV substation in
Wyoming

In the works is the Stegall 230-kV substation upgrade, which is being completed in a couple of phases. The relaying for the Stegall 230-to-Stegall 345-kV substation and the Stegall-230-to-Laramie River Station 230-kV line relaying has been replaced. The outdoor equipment at the substation was on hold pending a large Western Area Power Administration (WAPA) project at the substation, but is now restarting.

Originally scheduled to be complete in the spring of 2023, the upgrade to Leland Olds Station 345-kV substation has seen a shift to its timeline due to a few factors. The main factor is a generator interconnect and the new 345-kV line going around the east side of Lake Sakakawea called “Leland Olds Station-to-Tande.” After many internal discussions, the decision was made to rebuild the Leland Olds Station 345-kV substation to accommodate these new connections. The old Leland Olds Station 345-kV substation will be decommissioned as part of the project.

Parts of the Watertown 345-kV substation project have been completed. “This location is a little different since WAPA maintains this equipment on Basin Electric’s behalf, so they are managing the project which is funded by us,” Johnson says.

While there have been no major hiccups there have certainly been challenges. “Many of these facilities were originally built 40-plus years ago, and interfacing new equipment with existing infrastructure requires creative thinking and attention to detail,” Kuntz says. Through the experience and skill of the teams, these challenges have been overcome.

Additionally, Engineering has learned there are tools that can help the teams with these challenges. One of those tools has been working with Civil Engineering and its Surveying division to create 3D scans of existing equipment that provide accurate dimensions. They can then be used in the design phase to properly interface new equipment with existing equipment.

The current timeline has the final Aging Infrastructure project being taken to the board of directors for consideration in 2025 with an anticipated completion date in 2027.

With each new year comes new challenges and opportunities for growth as infrastructure nears the end of its lifespan. The Aging Substation Infrastructure Replacement Initiative brings new life to these substations and ensures that Basin Electric is providing reliability for its members far into the future, one project at a time.