CMP uses chopper to extend power line across Penobscot River

Posted Aug. 20, 2012, at 2:56 p.m.
A helicopter pulls the &quotstraw line" across the the Penobscot River on Monday as crews start installing transmission lines to span the 2,419-foot distance between towers in Bucksport and Winterport.
A helicopter pulls the "straw line" across the the Penobscot River on Monday as crews start installing transmission lines to span the 2,419-foot distance between towers in Bucksport and Winterport. Buy Photo

BUCKSPORT, Maine — Around 11 a.m. Monday, from the Bucksport end of a power line corridor connecting two counties over the Penobscot river, a small yellow helicopter rose into view over Winterport.

Starting on the west bank of the river, It floated slowly over a series of towers, delicately laying a ⅜-inch rope, or “straw line,” into cradles atop each tower, like a seamstress threading a needle. The aircraft tilted about 45 degrees as it pulled the line taut in Bucksport before flying back toward Waldo County, about an hour after first appearing.

The chopper was used by Central Maine Power Co. to span the 2,419-foot divide between towers on either end of the river. It was the first part of a three-step process to install 345-kilovolt conductors on the towers — part of a CMP’s “Maine Power Reliability Program,” a $1.4 billion investment into the utility’s transmission system.

Neighbors and local reporters gathered on River Road in Bucksport to watch the spectacle. One resident, Mary Gray, lives in a house next to the tower corridor, which was completed in July.

“It sure is a big change,” she said as she shot video of the helicopter at work. “My family’s been here 50 years. This used to all be woods.”

The straw line will be used to to guide a 1-inch-thick “hard line” through the towers. After that, huge winch trucks will pull a 1 ½-inch conductor, an aluminum wire with a steel core, through the towers along the hard line.

Construction Superintendent John Lekse, of the Kansas City, Mo.,-based company Burns & McDonnell, said his firm had managed helicopter operations like this one all over the world, but that it was still a dangerous strategy.

“There’s an element of risk with every line construction,” he said Monday. “There’s a lot of training that goes into this.”

The Maine Power Reliability Program project stretches from as far south and west as Eliot, east to Orrington and north to Cornville. An expansion of Livermore Falls’ substation is scheduled to start later this month.

As part of the project, five new 345-kilovolt substations and related facilities are being built to stretch 440 miles of new transmission lines. That will double the number of those substantial substations in the state.

“It’s basically reinforcing the backbone of our grid,” said CMP Spokeswoman Gail Rice on Monday. “The transmission lines we’ve got now were built 40 or 50 years ago. … The idea behind this project is to reinforce that system and ensure longtime reliability to customers throughout our service area.”

Rice also said the upgrade would increase the capacity for new power generation on the New England power grid.

The construction project directly affects more than 70 cities and towns in the state. Carroll said CMP is generally using existing corridors, but some places needed to be widened. In some cases, the company has had to buy additional land.

In April, Carroll said CMP estimated that between 2,500 and 2,700 people work on the project on a daily basis. Construction on the project is slated to be completed by mid-2015.

Follow Mario Moretto on Twitter at @riocarmine.

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