Helicopters and explosions: Power line takes shape

May 16 - McClatchy-Tribune Content Agency, LLC - Chris Hubbuch La Crosse Tribune, Wis.

 

With more than 80 percent of the towers in place, a new high-voltage power line known as CapX2020 is taking shape -- with some bangs -- along the Wisconsin side of the Mississippi River.

Xcel Energy contractors are using implosive connectors to splice the power lines together and say residents of Trempealeau County can expect to feel about a dozen blasts over the next two weeks.

Residents can also expect to see low-flying helicopters as crews string the lines between Galesville and Holmen.

When electrified this fall, the 345-kilovolt line will connect substations near the Twin Cities, Rochester and Holmen.

The work is part of CapX2020, a $2.2 billion initiative that Xcel Energy and 10 partner utilities say is needed to upgrade the power grid and connect wind energy resources to eastern population centers. The 48.6-mile Wisconsin portion was approved last year by the Public Service Commission at a cost of $211 million, to be paid by customers across the Midwest.

A similar transmission line known as Badger-Coulee, approved last month, will eventually connect the CapX line to Dane County at an estimated cost of $580 million.

The connectors are metal sleeves that slip over the 1-inch thick steel and aluminum cables. They are wrapped in plastic explosives that, when detonated, compress the sleeve.

This makes for a stronger and more uniform connection than would crimping the sleeves with mechanical force, said Brian Beste, transmission line construction superintendent for Xcel. Beste said the implosive connectors also require less hands-on work, which reduces impact on the right-of-way.

Used in Europe for decades, the technology is relatively new to the U.S., Beste said, and not all contractors have licensed explosive technicians.

Doug Berry, a lineman from Newton, Miss., demonstrated the technology Friday for a handful of news reporters, town officials and sheriff's deputies. Berry affixed three Implo connectors to pieces of cable that were moved to a safe distance -- about 100 feet. After three warning blasts from an air horn, boom.

Beste said Xcel has 88 connections to make, but because the detonations can be done in groups.

"You only hear one boom," he said.

lacrossetribune.com

http://www.energycentral.com/functional/news/news_detail.cfm?did=36192542