 | | | Specially trained linemen stand atop PG&E's lattice steel structures after being lifted by the helicopter hovering above. Photo Andy Scheck | | | | | | If you looked skyward in Lamorinda lately, you probably noticed helicopters hovering near local transmission towers. The linemen, air crew and their ground counterparts are working to upgrade Pacific Gas and Electric Company's 230-kilovolt transmission lines in the Lamorinda corridor. The project is a portion of a 27-mile-long upgrade stretching from the Oakley power plant substation to the Moraga substation in Orinda, said PG&E spokeswoman Tamar Sarkissian.
"This is a significant capacity and reliability project," Sarkissian said, "which serves approximately 26,000 customers. It is also the first time since its establishment in 1950 that this particular line has undergone a project of this nature."
Last year, a similar project in the East Bay was completed, Sarkissian said, but this 27-mile replacement-upgrade is one of the longest. The transmission towers, technically called lattice steel structures, are being upgraded with foundation reinforcements and the installation of 16.5-foot cage tops to raise the conductor.
Using helicopters allows PG&E to bypass the need for heavy trucks and equipment on the ground. This reduces the project's environmental impact, Sarkissian said. "Crews can work safely and quickly, and it's physically easier on the linemen than climbing each tower, which is 80 to 150 feet high," she said.
The high wire act is fascinating to watch. The specially trained linemen use a technique called "long lining," which involves hanging from a cable underneath the helicopter as they are transported from the ground onto the tower. PG&E was one of the first utilities in the United States to introduce long line work procedures, something still taught at the company's Livermore facility, Sarkissian said.
Long lining is now used nationwide. On the ground, more workers watch as the new line gets pulled along the towers, ensuring the wires stay off the ground and away from contact with each other. Temporary catch poles and wire baskets went up along the route as crews began pulling wire from Rossmoor through the Lafayette-Moraga Regional Trail.
The crews worked on Moraga Road near Buckingham Drive across from the Campolindo High School soccer fields, adjacent town offices on La Salle Drive, and at the north end of the Mulholland open space along Rheem Boulevard between Scofield and Harold Drives. They expect to work in Orinda through October, and plan to pull their last transmission line from Lafayette to Rossmoor late this month.
The project is scheduled for completion in November, contingent upon resources and safe weather conditions, Sarkissian said. But weather is actually one reason the upgrades have come about - peak summer demand or extreme weather conditions can max out the current transmission lines' capacity.
There will be no encore performance anytime soon for this high wire act. "We expect these upgrades to last more than 60 years," Sarkissian said.
PG&E construction and line upgrades in the East Bay began in January and are scheduled for completion during the summer of 2016. For more information, visit http://www.pge.com/en/safety/ccmoraga/index.page?WT.mc_id=Vanity_contracosta-moraga.
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Lamorinda Weekly, Moraga CA