
The Oil Change
Innovator Refines Transformer Maintenance Program
Chris Anderson is kneeling on hard concrete in front of a stubborn valve on a cold morning.
When you pride yourself on top-notch maintenance, this is what it takes.
And transformer oil sampling requires finesse – or it can get messy, fast.
Anderson, a Tennessee Valley Authority electrician, pulls out his Knipex pliers to open the valve. He hooks up a plastic tube, which quickly floods with oil and begins draining into a pan.
Next he moves the tube into a plastic bottle, collecting the first of two required oil samples – all part of the regular health checkup for transformer LNL-9267-4, at Oglethorpe substation in Catoosa County, Georgia.
For the second sample, Anderson attaches a glass syringe, tapping out the air bubbles once it’s filled.
The samples are almost ready to be shipped to TVA’s Central Labs for analysis.
Almost, but not quite.
Electrician Chris Anderson has to get low to the ground to reach the sampling site.
Is That a G? Or a 3?
Now comes the really tricky part.
Funnily enough, it’s the handwritten label.
Fellow transmission maintenance electrician Sarah Stewart, who has excellent penmanship, removes her gloves so she can write even more neatly than usual and avoid smearing oil on the label.
Every single number and letter must be legible.
If the label can’t be deciphered, the entire sample will be in limbo. Someone will have to try to match up the sample data with the transformer it comes from. If they fail, the sample will have to be retaken.
Aaron Gordon, transformer systems inventory manager, describes the problem: “Maybe it's a G? Maybe it's a 3? When you're out in the middle of a substation and it's cold and you're in a jacket and gloves collecting oil, it's not conducive to holding a pencil.”
So Gordon set out to create a better system.
Aaron Gordon, transformer systems inventory manager, devised a plan to eliminate the need for handwritten labels.
‘Blood Work’
While it might seem like a picky bookkeeping issue, there’s a lot at stake.
Transformers keep electricity flowing reliably on the grid for TVA and its 153 local power company partners.
The oil tests serve as an early warning system of potential problems.
“These tests are essentially the blood work of a transformer that can diagnose failing conditions,” Gordon said. “The gas found in the oil can help us understand what's going on inside the transformer.”
You’ve probably driven past transformers – large metal boxes with cylindrical porcelain or glass bushings on top. They’re located at electrical substations, usually in less populated areas.
TVA’s seven-state transmission network includes 446 major transformers. They enable TVA to transport power over long distances by stepping up the voltage, then ramping it back down for distribution to homes and businesses.
Each of these transformers gets regular oil checkups.
The results come back green (healthy), yellow (keep a watch on it), or red (escalate the situation).
Transformers are handmade, and the innards are quite delicate – paper-wrapped copper wires coiled into circles and discs, bathed in purified oil that circulates through the coils like blood. They’re designed to run with up to 35,000 gallons of oil at almost 150 degrees Fahrenheit.
Maintenance crews don’t open them unless they absolutely must.
“Rather than going for exploratory surgery, we just do this blood work,” Gordon said.
All transformers, such as these at Oglethorpe substation in Catoosa County, Georgia, get regular oil tests.
A Better Mousetrap
But the handwritten labels were problematic.
Gordon devised a plan to automate the process, and he pitched it at an internal TVA innovation contest.
Imagine “Shark Tank” just for electrical transmission experts.
Judges picked Gordon’s plan among the winners.
His prize? Funding to implement his project.
Beginning this year at Raccoon Mountain Pumped Storage Plant near Chattanooga, Tennessee, TVA transformers are being labeled with laser-annealed stainless steel tags marking the precise location where oil samples are taken.
This, Gordon explains, clears up another problem with the old system: Clarifying which serial number belongs on the label.
“These are highly technical devices and they're tall,” Gordon said. “Everything will have a serial number stamped on it – every pump, every valve, every fan, the control cabinet. … There may be 100 numbers stamped on this thing, and 99 out of those 100 numbers won’t help.”
Going forward, the maintenance crew will simply scan a QR code on the permanent tag, then use a small portable printer to generate the oil sample labels.
At the lab, the transformer’s unique identifying number and test results will be uploaded automatically into databases that track maintenance schedules and the performance of TVA’s equipment.
“The laboratory doesn’t have to guess,” Gordon said.
Permanent tags on transformers will ensure the correct serial number gets attached to each sample.
‘A Lot of Good Ideas’
TVA director of transmission maintenance Drew Reid praised Gordon’s innovation.
“We had equipment out there that potentially could have had an issue,” Reid said. Gordon’s new system “really improves our knowledge of the health of the equipment.”
As TVA modernizes its transmission system, Reid stressed the value of encouraging innovation at a grassroots level, such as with the contest.
“A lot of good ideas have come out of it,” said Reid, one of the judges.
The innovation contest also helps participants learn project management skills, Reid said.
“Some of the folks that bring ideas to the table and their projects get funded, you get to see them walk it from idea generation to concept all the way through execution and dealing with the financial element.”
One transformer oil sample must be collected in a glass syringe.
Good Maintenance
Gordon’s project saves TVA the costs of troubleshooting illegible labels and conducting do-over oil tests.
Plus, it means oil test results can be analyzed in a timely fashion so any potential problems can be caught before they escalate to transformer failure.
Keeping current on maintenance is crucial, Gordon said.
“Rather than run to failure or just waiting until it breaks down, we do a lot of good maintenance that prolongs the life expectancy on these things to way beyond the manufacturer’s recommendations.”
As for his interest in innovation?
“Innovation is a result of my desire to make things around me more efficient,” Gordon said. “You have to get creative. You don’t want systems that are wasting your effort.
“In this case, I just happened to be in a unique position where I was able to see this process from beginning to end to understand the waste. When you're in the field, you might not have to redo a sample but two or three times a year. But if everybody's redoing a sample two or three times a year, those add up.”
Photo Gallery
Transformer oil samples await delivery to TVA’s Central Labs.
The insides of a transformer – such as this one undergoing repairs – are quite delicate.
Oil sampling results are like blood work to monitor transformers’ health.
PHOTO AT TOP OF PAGE: Regular oil sampling is vital to preventive maintenance on TVA’s electrical transformers.