By PHILLIP BOCK
MANITOWOC, Wis. (AP) — A helicopter took to the skies of Manitowoc County recently armed with an oversized saw and a mission to trim trees.
American Transmission Co., which operates a 345,000-volt energy transmission line that runs from the Point Beach Nuclear Plant in northeastern Manitowoc County west across southern Brown County, hired the helicopter to trim trees along the transmission lines.
The company hired by ATC, Aerial Solutions, utilizes helicopters equipped with heavy-duty air saws with rotary blades suspended on a 90-foot vertical boom to trim trees near transmission lines.
“We’ll be using the helicopter and air saw to side-trim trees at the edge of the right-of-way,” Ben Gura, senior vegetation management specialist with ATC, told HTR Media. “This work will help us ensure the safe and reliable operation of the electric system.”
ATC performs routine vegetation management on its 9,480 miles of transmission lines in five-year cycles, according to Luella Dooley-Menet, a spokeswoman for the company. Ground-based vegetation management was performed on the Manitowoc County stretch of transmission line about a year ago, and additional maintenance was recently completed.
“The aerial saw is being completed to help control the growth of trees on the outer edges of the right of way,” Dooley-Menet said “We’re coming back a year later just to do additional maintenance.”
Using the helicopter-based trimming method is more efficient than using ground-based crews — it can do in an hour what a ground crew can do in a week, Dooley-Menet said, and the helicopter is able to trim areas of transmission line right-of-way that is difficult to reach by ground crews.
“The helicopter has shown to be highly productive and efficient, especially when compared to using a ground-based crew,” Dooley-Menet said. “Since the helicopter trims from above, it allows for work to be completed in difficult terrain and have little impact on sensitive areas such as wetlands or waterways.”
The method has been used previously by the company in the upper peninsula of Michigan, but is now starting to see wider use in Wisconsin.
“This is a technique we’ve used in some areas of our service area and we’re using a little bit more in areas of Wisconsin than we have in years past,” Dooley-Menet said. “It’s highly efficient and highly effective. It’s been a good technique.”
Ariel Solutions, a family-owned business based in North Carolina, pioneered the use of helicopters to trim trees in 1985. The company controls every aspect of the business and fabricates the saw used in the tree trimming in-house.
The hardware consists of multiple 24-inch rotary blades powered by a motor suspended on a vertical boom. The saw trims away trees and other vegetation as the helicopter flies slowly along the treeline.
The saw is controlled by the pilot in the helicopter, who is assisted by a ground crew.
“The crew flies for approximately an hour and then stops to refuel and to perform maintenance and safety checks,” Dooley-Menet said. “I believe they get about four to five hours of flying time in a day.”
It’s a delicate process, as crews have to be careful near the high-power transmission lines —and the work is rarely completed near residential areas. Recently, landowners who live near the transmission line were notified in advance that the work would be underway.
“There is a lot of planning done ahead of time to find where this technique can be safely and effectively used,” Dooley-Menet said.
The work, which is weather dependent, was expected to take a week to complete in Manitowoc County.
Information from: HTR Media, http://www.htrnews.com