The Hartselle Connection

In July of 2009, a 50-year-old transformer at Hartselle Utilities’ District Substation on Thompson Road blew up. After crews switched to the backup transformer at the substation and restored power, Hartselle Utilities General Manager Ferrell Vest had one request for Electric Superintendent Jonathan Hampton: fix it, and don’t let the power go out during the process.

Hampton ordered a new transformer, keeping his fingers crossed that the backup transformer, also built in 1959, would hold. Given a three-month projected delivery schedule for the new custom-built transformer, Hampton began working with Stewart Engineering to develop a plan to redistribute the system’s electric load away from the District Substation during the changeout.

Using computer modeling to predict what would happen as loads were increased along parts of the system, they pinpointed lines which were not big enough to carry additional load. HU crews reconductored these lines to make sure they could hold the larger loads. Then, Hampton and Stewart Engineering developed a 34-step plan to switch the electric load from the District Substation to the Primary Substation.

“Years ago, something like this would have meant a power outage to parts of our system,” Hampton said. But in today’s world, with so many residents and companies relying on computers and other electrical devices, that was not an option. When the transformer was delivered, the plan was put into place. Crews switched power to the primary substation, brought in a crane to remove the old transformer, put the new one in place and energized it, then reversed the process to shift the power load back to the District Substation. The actual changeout took about a week.

Hampton admits to holding his breath when the power was switched away from and back to the substation. “With 34 steps in the process,” he explained, “if we had gotten even one in the wrong order, or if the computer modeling had been wrong, the power would have gone out.”

“It was impressive to watch how this came together,” says HU General Manager Ferrell Vest. “This is not the situation we chose to be in, but it’s what we found ourselves in. Our crews did what they needed to do.”

A good bit of the work performed had been planned during HU’s five-year Capital Improvement Plan – and even provided for in this year’s budget – Hampton explained, “but we just didn’t know we would do it that soon,” he laughed.

He added that the engineer from Stewart Engineering was very complimentary of HU. “He said that our five-year plan, and our board following through with the recommendations in it, made it much easier for this to happen successfully.”