the aging of america transformers
DESCRIPTION
Using Condition Monitoring to assess the aging of power transformerTRANSCRIPT
JLG Associates, LLC
“The Aging of America’s Transformers”
by
Jon L. Giesecke, Director, JLG Associates, LLC
(610) [email protected]
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