Kathleen Davis, Associate Editor
The American Society of Civil Engineers’ (ASCE) 2002 Electrical Transmission Conference: Electrical Transmission in a New Age, held in Omaha, Neb., in September, brought engineers from all over the U.S. and Canada to share research, development and information on their T&D work. The conference was opened by a keynote address from Gerald Krause of the Omaha Public Power District and featured presentations from Florida Power & Light, Texas Tech University, Bonneville Power Administration, Hydro-Quebec and the U.S. Department of Agriculture, among others.
In the session on structural analysis, Power Line Systems vice president Otto Lynch discussed a comparison of advanced analysis techniques to traditional methods, defining advanced analysis in the terms of finite element modeling (FEM), with computer-based numerical technique where structure is broken down into many small components. In his opinion, FEM will yield better answers than the more traditional “hand” method, or even the software based on that traditional method.
Leon Kempner, Jr., with the Bonneville Power Administration also discussed modeling and analysis in his presentation on lattice transmission tower analysis and BPA’s LIMIT program. He put his reasoning quite succinctly.
“Why do we need advanced tools?” he asked. “Because we’re not sure simple truss models are the way to go.
“Traditionally, we’re used to plugging in one number and coming out with the ‘right result.’ Unfortunately, there are a lot of numbers involved in creating these variations.
“With these advanced tools, you might be able to do a little more in defining the capacity of the tower.”
Differences in utility poles were also discussed at the conference, including in-depth analyses of fiberglass composite utility poles and crossarms, as well as a look into hybrid poles, spun concrete poles and steel-finned pipe foundations for single pole structures.
Wesley Oliphant of Newmark International Inc. told his audience that “poles don’t have to be dull,” showing his audience a picture of one spun concrete pole with a “knot” tied in the center.
He went on to add, “We’re building poles today with the ground line capacity of the 10 million-foot-pound range. That’s a big pole.”
The conference also saw updates on ASCE manuals and design guides currently in the works, and consulting engineer Robert Nickerson gave guidelines for upgrading and uprating existing latticed transmission structures.
“There’s an excellent service life for the majority of latticed towers,” Nickerson stated, pointing out the key issues: there are new design standards to upgrade, there have been significant advancements in analytical tools and that material availability–i.e., that some older equipment will no longer be manufactured– should be taken into consideration.
The highlight of the conference was the presentation of H. Brian White, an independent transmission consultant who was within days of his 80th birthday. While his speech on cross-rope suspension structures with Roberto Behncke of Power Engineers was quite informative, it was his stories of his own history in the field that captured audience appeal.
Talking about an early career project attempting to cross a difficult Canadian valley with transmission lines, White spoke eloquently.
“The question that had been put to me was to return the downed towers where they would be safe, but it wasn’t the right question. The question was getting power from here to there reliably. That was the real question.”
He related that during the project he was talking with a friend about the problem, and his friend commented “White, what you need is a sky hook.”
“Twenty-five cents for two glasses of beer and a tip for some of the best advice I’ve ever received,” he told the attendees.
“It was a long time ago,” he added. White said that the completed line went into use in 1955 and “never had a day’s trouble since.”
“And, in the end, we ended up using no towers at all,” he stated, referring to the slides showing the line slung across the valley high against the blue Canadian sky with just a whisper of leaves from the trees below.