By early fall, 28 miles of Corn Belt Power Cooperative’s 70-year-old 69 kilovolt transmission line from Wallingford Switching Station to Springfield Switching Station in Emmet and Kossuth counties will have been completely rebuilt. New western red cedar poles and heavier conductor will improve strength of the line and reliability of service to member co-ops.
Highline Construction, Paynesville, Minn., has been hired to rebuild the line for the cooperative. The project started May 10 with Corn Belt Power crews completing switching to open the first of four sections of line and rerouting power near Alliant Energy’s Armstrong and Corn Belt Power’s Ringsted substations. Finishing that portion first will allow the substations to return to service before the summer peak occurs.
Kevin Bornhoft, vice president, engineering and system operations, explains, “We have a long-standing agreement with Alliant Energy to serve loads on each other’s system. This agreement allows both companies to build less transmission by operating combined systems.”
Highline Construction will take down the 1951 vintage conductor and roll it up. All of the old TS-1 configured poles and crossarms will be removed. The new “line post” pole design will have attached polymer insulators rather than crossarms with insulators.
The next section of line to be rebuilt runs east to Springfield. The third and fourth sections extend from Ringsted Substation west to Vernon Substation and Wallingford Switching Station. Corn Belt Power crews will install new switches, insulators and bus in Wallingford Switching Station when nearby sections of line are out of service during the rebuilding project.
Bornhoft explains that Corn Belt Power selected the Wallingford-Springfield line to rebuild this summer in response to studies that showed it could experience low voltages during summer peak times due to certain contingencies. Depending on weather conditions that crews encounter, the entire project is anticipated to be complete by early fall. Crews may encounter wetter conditions in marshland located in middle sections of the line, which could hamper progress.
“We have over 500 miles of aging line to replace in the next 10 years, which will be completed by both contractors and our own crews,” Bornhoft said. “Much of the conductor and static wire on those lines are approaching 70 years old and some will be approaching 80 years old as we make progress over the next 10 years. We want to get line replaced before it fails.”