Substation Reconfigured for Solar
Among the cornfields in southeastern Iowa, near the small town of Wapello, where the Iowa and Mississippi Rivers converge, lies the Newport Substation.
In 2019, the Central Iowa Power Cooperative (CIPCO) embarked on a project to reconfigure its Newport Substation and add a line in response to a request for a solar interconnection. The substation, located slightly to the south of Wapello, Iowa, serves as an access point for generation onto CIPCO’s eastern Iowa power grid.
“Based on our experience with substations and interconnects,” said Patrick Deibel, P.E., a technical manager with Ulteig’s substation team, “Ulteig was awarded the design to reconfigure the Newport Substation and connect it with a new solar project being built on 800 acres adjacent to the substation.”
Working on the Newport Substation was familiar ground for Ulteig’s engineers. Just two years earlier, Ulteig assisted CIPCO in the redesign of a 161 kV ring bus to expand the Newport Substation to provide more reliability to the overall system. During the start of design and construction in 2017 and 2018, a future line position was not needed, but the new design was added to provide for future positions to be integrated into the expansion.
Change to Meet Future Demands
In 2018, CIPCO agreed to purchase 100 percent of the energy and capacity output for 25 years from the 127.5 MW Wapello Solar LLC facility. Wapello is the largest solar project located in Iowa. As the engineer
of record, Ulteig provided:
- Electrical physical layout and design for the major equipment, including physical section views, conduit layout, grounding design and lightning protection.
- Electrical design, which included schematics, wiring diagrams and control panel layouts for the protective relaying & SCADA equipment.
- The structural engineering, which included steel fabrication and foundation designs.
- Project management services for the design engineering portion of the project.
Overcoming Challenges
Working on an existing site can be a challenge, as drawings may not always be accurate. During construction, the contractor discovered that the new substation dead-end and associated metering equipment could not be located where designed. Ulteig engineers collaborated with CIPCO engineers and the contractor to overcome this challenging new development and came up with a creative solution, which included relocating the equipment and maintaining proper electrical clearances.
Scheduling became a concern when the Generator Interconnect Agreement (GIA) and funding were not in place until Dec. 2019. The in-service date of Nov. 1, 2020, made for a roughly 10-month project schedule to execute engineering, material delivery, construction and commissioning. To meet the Nov. 1 deadline, Ulteig reduced the engineering design process from the typical eight or nine months to just six and a half.
Success: Driving Down Costs
When the site was set up to add an additional line, the only major change required was to relocate an existing line to an open position in the substation, thus terminating the Wapello Solar line in the least expensive and most constructible position. Cost savings were implemented in the line location swap by reusing equipment and relocating it as necessary.
“By relying on an experienced team,” said Deibel, “as well as the team’s knowledge of the project based on its previous work at the substation in 2017, we executed a quality design in the required timeframe for the solar farm to connect to the grid.”
Award-Winning Project
The American Council of Engineering Companies (ACEC) of Iowa presented Ulteig with a Grand Prize Award for the Newport Substation Interconnect. This work was recognized as the top project in the energy production category of the 2021 ACEC Engineering Excellence Awards competition.
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