Coal, Nuclear

Switchyard Transformers Overlooked in Power Quality Equation

Issue 10 and Volume 107.

Plant performance measurement often stops at the point where power enters the plant switchyard. Yet minor transformer failures can have devastating impact on plant performance and system reliability. Such concerns can only be heightened in the wake of the U.S.-Canadian blackout of August 14.

Power factor testing for transformer reliability and other specialized engineering services is something Doble Engineering Company has been supplying to the electric power industry since 1920. Rick Ladroga, manager of business development for Doble Engineered Strategies, says transformers get less attention than other elements of a power plant, creating the potential for outages traced to a low-cost item. Imagine, for example, a 1,000 MW coal or nuclear plant tripping off line during a peak period as the result of a failed transformer bushing?

“We have two major problems,” says Ladroga. “Industry pioneers such as General Electric and Westinghouse are no longer in the large power transformer business and big transformers are no longer being built in the U.S. The standard used to be to overbuild them in terms of reliability and longevity.”

The second major area of concern, says Ladroga, is the loss of utility in-house technical expertise. “Not so long ago,” he says, “nearly every major utility had at least one individual on staff who was considered a transformer specialist. This specialist was generally responsible for transformers throughout the company. But expertise such as this is rapidly disappearing – the direct result of a graying workforce, corporate downsizing, and early retirement.”

Compounding the problem is the lack of new talent to fill those voids. “There’s been a significant decrease in the number of electrical engineers majoring in power engineering and electrical power programs at most colleges and universities have been dropped in favor of electronic and computer science programs,” says Ladroga.

The entire U.S. fleet of transformers is aging and will ultimately require replacement, he says. Power companies have two choices: Continue using their existing transformers, or replace them with new units from overseas. So the answer, he says, is to provide the surviving operating engineers and managers with all the information they need to make informed decisions with confidence.

“We recognize these needs at Doble,” says Ladroga. “We make use of our own enormous database and technical expertise to assess the condition of existing power transformers in order to provide our clients with very valuable information regarding the future operation and maintenance of their assets. The goal is to ultimately offset the purchase of new capital equipment by extending the life of the existing units, wherever possible, and through our conferences and seminars we have done that.”