the aging of america transformers

JLG Associates, LLC

“The Aging of America’s Transformers”

by

Jon L. Giesecke, Director, JLG Associates, LLC

(610) 518-1615jlgassociatesllc@yahoo.com

The Weidmann Conference2006

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How Old is Old?

■The aging of the electrical infrastructure in the United States is a serious problem!!

■Until recently this problem has slipped thru the cracks. A new level of awareness is needed as these aging transformers are failing.

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Average Age

■As of today, our transformer population has an average age of 40 years

■The published life expectancy of many of our transformers is 40-50 years

■TIME’S UP…..NOW WHAT?

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WE MUST BE PRO-ACTIVE

WHAT’S NEEDED?

■The best asset management program using condition monitoring.

HOW?

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WE MUST BE PRO-ACTIVE

■ I have dedicated the past decade in search of the optimal tests for condition assessment of Oil Filled Power Transformers and their Sub-Systems.

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WE MUST BE PRO-ACTIVE

■ During that time, I helped develop a program using the newest technologies and the very best equipment, methods and techniques for condition assessments.

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WE MUST BE PRO-ACTIVE

■ Infrared, Vibration Analysis, DGA, Oil Quality and Functional Testing of the cooling systems and load tap changers was the backbone of the process.

■What was needed was an easy and reliable test method for Partial Discharge.

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WE MUST BE PRO-ACTIVEUSING THE NEWEST TECHNOLOGY

■A Partial Discharge (PD) testing method using acoustic sensors and a high frequency current transducer is now available

■This increases the protection factor for these utility industry assets:

Transformers, LTC’s, Lightning Arrestors, Pumps, OCB’s, GIS, etc.

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WE MUST BE PRO-ACTIVE

■This presentation will describe the process for PD detection / location and answer many key questions that may arise.

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■One Question…..What do Oil Circuit Breakers, Load Tap Changers and Voltage Regulators have in common?

■Anybody??????

However, before we start…..

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■Answer…..They all have contacts which arc under insulating oil!

Ahaa!

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■Something that shouldn't arc under oil……

■ANYBODY????

Abnormal Arcing(bad ju-ju)

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OIL FILLED POWER TRANSFORMERS

Abnormal Arcing(bad ju-ju)

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LET’S TAKE A WALK DOWN MEMORY LANE

■The Date…..1969■The Viet Nam War■Peace & Love■DGA■My Discharge from the Navy■Hippies & Flower Power■Bell Bottoms

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Let’s take a walk down memory lane.

Did he just say DGA???

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■ I was a maintenance electrician – high volt group.

■The high volt group was responsible for OCB, LTC and Regulator maintenance.

■Everything was based on time and operations / fault trippings

Back in the “OLD DAYS”

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■The most high tech device we all used was the Cincinnati Analyzer for breaker timing.

■Like many of you, I licked many charts until they came out with self stick. (new technologies)

Back in the “OLD DAYS”

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■ Then a brand new technology came into existence….DGA on Transformer Oil. By the way it was slow to catch on.

■ And yes, we were still using the old Cincinnati Analyzer

■ And doing overhauls based on time and operations

Back in the “OLD DAYS”

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I was threatened with bodily harm when I suggested doing DGA on an LTC

I imagine I would have been institutionalized if I had suggested doing DGA on OCB’s

Back in the “OLD DAYS”

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■BUT, as most of you know and are probably doing; both LTC and OCB problems are easily detected by DGA

■What about voltage regulators? Aren’t they in the same family?

■Arcing Contacts under oil, exhibit much of the same characteristics.

BACK TO THE FUTURE

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■And of course there came into major use in our industry, “Infrared Thermography”

■Everyone is doing IR■OCB and LTC infrared is very telling and

useful for diagnosing problems■A full set of functional tests on LTC’S

saved many costly failures

Back to the Future

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■Then along came “Ultrasonic Analysis”■Computerized motion analysis and capture

of 1st trip.■Wave Shape analysis,■Etc., Etc.

Back to the Future

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■A combination of ultrasonics and electrical capture of an arc is being done.

■And with it, the ability to analyze…■Source Locate■Trend■And make the big dollar decision on when

to say when.

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Today, we are able to capture and analyze a burst of acoustic

energy……BUT, HOW MANY DO???

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And Expand a selected Portion for a closer look

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And Expand even more to measure the Frequency Content.

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Technology today is able to capture the acoustic signal from the

operation of an LTC.

BUT, HOW MANY DO???

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Then expand and analyze the acoustic signal!

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Technology today is able to capture the Arcing from the operation of an

LTC.

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Then Expand and Analyze the Arc

B C

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Expand again to show the arcing contact and the follow-thru.

(B Phase)

B

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Then Expand C Phase for analysis.

(C Phase)

C

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AND BY THE WAY….

Did you realize???

This was a VACUUM TYPE LTC!

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■ I NOW HAVE THE ABILITY TO INSPECT VACUUM CONTACTS IN AN LTC DURING AN OPERATION….ALSO

■MECHANICAL LTC’S■ OCB’s ■ VOLTAGE REGULATORS

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■ ALSO THE ABILITY TO INSPECT OIL FILLED TRANSFORMERS AND SUPPORT EQUIPMENT DURING NORMAL OPERATION

■ CORE, WINDING, BUSHING LEADS■ PUMPS■ LA’S■ LTC’S

DETECTING PD AND ARCING IS FAST AND EASY

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“The Rest of the Story”

■When you look at the next few slides……

■Remember the top screen is acoustic energy…..

■The bottom screen is electrical energy…..

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THE COMPLETE LTC PICTURE FROM PREVIOUS SLIDES

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PARTIAL DISCHARGE IN MPT/GSU

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Cursors measure difference, PD is confirmed in this GSU

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Expand 1 Burst for a closer look.

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Expanding more shows #3 is closest (notice the spike shape)

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The fault Location Screen (front view) Pink Ball shows location of

PD.

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The fault Location (top down view)

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BAD LIGHTNING ARRESTOR (bottom screen only)

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ONE SPIKE FROM THE LA

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ONE SPIKE FROM PD (flip back and forth)

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Combining Data,a Holistic Approach

■ Partial Discharge Detection■ Infrared Thermography■ Vibration Analysis (main tank and pumps)■ Functional Testing of Cooling System & LTC■ DGA & Oil Quality Review■ Furan Analysis■ Review of Transformer Loading History

■ All done on energized, loaded transformers

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Combining Data,a Holistic Approach

■We only talked about one of the technologies from the list.

■Many times two or more methods point to the problem.

■Don’t short change yourself.■This knowledge is available, learn to do

a complete condition assessment.

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THANK YOU

QUESTIONS PLEASE