When a Sikorsky-64 air-crane helicopter lifted a 15,000 lb transmission structure near Kearney, NE, and gently placed it into pre-dug holes, the rebuilding of a 230-kV power line owned and operated by the Nebraska Public Power District began.
The line was one of 37 transmission lines damaged during the New Year’s Day weekend ice storm and was the focus of a Media Day event. Onlookers watched as the three-pilot helicopter crew worked swiftly, putting into place 55 out of the planned 439 structures that will be replaced during the remainder of March. The work took place along the Riverdale and Crooked Creek segment and will continue on another segment between Riverdale and Grand Island.
“Using the air-crane to move the structures from the fly yard and into place allows NPPD to expedite restoration of the transmission line,” stated Barry Campbell, general manager of operations for NPPD. “Our goal is to have the entire line up before our peak load comes this summer.”
Campbell explained that the schedule, barring delays from the weather, will have the structures into place by the end of March, with the stringing of conductor and replacement of insulators following on the heels of setting the structures.
The air-crane, operated by Erickson Air-Crane, a company specializing in heavy lift operations, easily lifted the pre-assembled structures from established fly-yards to waiting ground crews from PAR Electrical Services. A second crew set the structures and then was moved swiftly between different sites along the route by a helicopter from Winco Power Services. Estimates were that eight structures could be lifted and set into place in one hour’s time.
More than 1,000 miles of line segments and 1,137 structures on NPPD’s electrical grid were damaged, broken, or destroyed by the storm, including approximately 40 latticed, steel structures south and east of Kearney. The steel structures support NPPD’s high-voltage, 345 kilovolt transmission lines. Reconstruction of the 190-foot towers will be completed using tall cranes on the ground that lift and hold the steel sections into place while crews secure the structure into place.