ISSUE 18

February 2022 transformer-technology.com ISSN 2642-2689

Transformers:
The Heart
of the
Power System
Interview with Wilfried Breuer Managing Director at Maschinenfabrik Reinhausen
What is a Transformer Save?
Transformer Condition Assessment: Moving from Data to Actions
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4 TABLE OF
CONTENTS

Index Contents

Table of
Table of Contents_04

Editors & Impressum_10

Editor’s Letter_12

Interview with Wilfried

Breuer, Managing Director at

Maschinenfabrik Reinhausen_14

What is a Transformer Save? _24

Integrated solutions from Power

Diagnostix by Megger for factory 14

and laboratory partial discharge Interview with Wilfried Breuer
testing_32 Managing Director at
Maschinenfabrik Reinhausen
There’s a 70% chance of your

transformer failing in the next

year_38

Tragedy & Expense: The High Cost

of Low Electrical Safety_40

Digital twin technology of

Sensformer™ Advanced –

A significant step in the

digitalization of transformers_46

Deploying condition-based

maintenance technologies to

extend the life of renewable energy

assets_50
 February 2022 5

40
Tragedy & Expense: The High
Cost of Low Electrical Safety
24 The physical environment of any factory is the
setting where risk-based behaviors take place,
What is a Transformer Save? with both machinery and power systems
posing the highest threats to worker safety.
This is not a trick question. To most readers Structuring out hazards through technology
of this tome, the answer is simple. A bona- drastically reduces the opportunities for
fide transformer "save" is when action is taken incidents to occur, and as an added bonus,
to protect a transformer, the action being increases the reliability of assets and
motivated by available information that is efficiency of the team.
predicting a failure.
32
Integrated solutions from
Power Diagnostix by Megger
for factory and laboratory
partial discharge testing
46
Digital twin
technology of
38 Sensformer™
Advanced –
Technical Advisors’ Column: A significant
There’s a 70% chance of your step in the
transformer failing in the digitalization of
next year transformers

50
Deploying condition-based
maintenance technologies to extend
the life of renewable energy assets
By implementing condition-based maintenance
technologies into renewable generation, energy providers
can offset risk, extend the life of assets, and reduce the
cost of repowering a facility.
6 TABLE OF
CONTENTS

Index Contents

Table of
PTTX Late-model Eco-friendly

Transformer Core

Boosting

Low-carbon

Development_56

Reliability: 56
PTTX Late-model
A Compound Effect_60
Eco-friendly Transformer
Women of Note: Aleezeh Shahid, Core Boosting
Low-carbon Development
Senior Analyst at Power Technology

Research_67

Transformer Condition

Assessment: Moving from Data to

Actions_68

2022 IEEE PES T&D Conference and

60
Exhibition: Reconnecting in the Big

Easy_76

Leading the Charge: Coatings

Reliability: A Compound
Effect
Stand on Front Lines in Protecting
What is your definition of reliability? Check your
answer against this interesting discussion on
Electrical Components_80
critical asset reliability by Traci Hopkins.
Coming in April_88
Transformer Technology February 2022 7

Issue 18

67
Women of Note: 76
Aleezeh Shahid, Senior 2022 IEEE PES T&D
Analyst at Power Conference and
Technology Research Exhibition:
Pre-show Interview with
Wayne Bishop Jr.
Vice President of
Meetings & Conferences
for IEEE PES

80
Leading the Charge:
Coatings Stand
on Front Lines in
Protecting Electrical
Components
Coatings are the first line of defense to safeguard
the critical infrastructure in the face of a variety of
conditions. Selecting the proper coating materials

68
to help preserve power generators, transformers,
switchgear and more is crucial.

Transformer Condition
Assessment: Moving
from Data to Actions
Correlative analyses and data analytics are
gaining more importance as they enable
users to evaluate the probability of failure by
using different parameters, which can
be supportive or contradictive to each other
in their individual failure mode assessment.
Once a potential incipient fault has been
identified, a set of actions for rectification
can be determined.
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See Through
Transformer Technology February 2022 9

Issue 18

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10 EDITORS &
IMPRESSUM

Impressum Editors

Editor in Chief Editor in Chief

Alan M. Ross, CRL, CMRP Alan M. Ross, CRL, CMRP
Transformer maintenance
Associate Editor in Chief and
and reliability
Chair of the Technical Advisory Board
Corné Dames
Independent transformer consultant

Technical Advisory Board Member

Associate Editor in Chief
Edward Casserly, PhD and Chair of the Technical
Senior Scientist, Transformer oils Advisory Board
Tony McGrail, PhD Corné Dames
Asset management & Condition monitoring Independent transformer
Alexander Doutrelepont consultant
High voltage bushings & insulators
Transformer oils
Maria Lamorey
Industrial OEM manufacturing

Contributing Editors
Diego Robalino, PhD, PMP
IEEE Senior Member
Alan Sbravati, ME, MBA Technical Advisory
Transformer insulating materials Board Member
Marco Tozzi, PhD Tony McGrail, PhD
Diagnostics and asset monitoring Asset management &
Curtus Duff Condition monitoring
Power transformer design
Traci Hopkins, IEEE Member
Transformer Condition Assessment
Jon Trout, PE
Electric utility

Graphic design Technical Advisory

BE Koncept Communication Boutique Board Member
Alexander Doutrelepont
Photo Cover High voltage bushings
Shutterstock & insulators
Sales & Marketing
Rachel Linke
rachel.linke@apc.media
Kevan Sears
kevan.sears@apc.media
Technical Advisory
Sales & Marketing Americas Board Member
Maria Salamanca Edward Casserly, PhD
maria.salamanca@transformer-technology.com Senior Scientist,
Transformer oils
Sales & Marketing Mexico
Fernando Campos
fernando.campos@transformer-technology.com

Sales & Marketing Brazil

Marcelo Braga Technical Advisory
marcelo.braga@transformer-technology.com
Board Member
Marketing Global Maria Lamorey
Marin Dugandzic Industrial OEM
marin.dugandzic@apc.media manufacturing
Transformer Technology February 2022 11

Issue 18

Contributing Editor
Diego Robalino PhD, PMP
ISSN 2642-2689 (Print) IEEE Senior Member
ISSN 2642-2697 (Online) Transformer condition
assessment and
DIGITAL Membership diagnostics
Free

Transformer Technology magazine is a quarterly

magazine published by APC MEDIA LLC, 11210
West Rd, Roswell, GA 30075, USA. Published
content does not represent official position of APC
MEDIA LLC. Responsibility for the content rests Contributing Editor
upon the authors of the articles and advertisers, Alan Sbravati ME, MBA
and not on APC MEDIA LLC. APC MEDIA LLC Transformer insulating
maintains the right to keep the textual and materials
graphical documents submitted for publication.

Copyright and reprint permission

Abstracting is permitted with credit to the source.
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For other copying, reprint or republication Marco Tozzi ME, MBA
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transformer-technology.com
Contributing Editor
Curtus Duff
Power transformer design

Contributing Editor
Traci Hopkins
Transformer Condition
Assessment

Contributing Editor
Jon Trout PE
Electric utility
12 LETTER FROM
THE EDITOR

Dear Readers,

When we were planning the themes It is no coincidence that we pub-

for 2022, to provide structure for our lished this issue on February 14 th,
weekly Body of Knowledge releases, and Valentine’s Day. A dear friend and leader,
for the compiled digital magazine, we believed Dale Bissonette of Good Place Holdings once
it was time to expand the themes beyond the said as I entered the world of transformers at
power transformer and the technical aspects SDMyers, “You will find that you will fall in love
relating to those transformers, without moving with transformers before you know it.” He was
too far afield. This February magazine has done right. It kind of sneaks up on you; not love at
that to a lesser extent. Focusing on Transformers: first sight, but a growing understanding of the
T h e H e a r t o f t h e P o w e r S y s t e m begins to importance of transformers on pretty much every
formulate the direction for the future in that we aspect of modern-day life.
address a system not just the heart of that system.

For February we have limited the other aspects of

the power system, but in the future, you will see
an expansion of our content to include the entire
power system, under a new community called
Power System Technology (PST). That expansion
begins in earnest in April and for the rest of the It is no coincidence that
year. Of course, our Bushings, and our Oils & Fluids we published this issue on
issues will remain as stalwarts of October and February 14th, Valentine’s
December issues, as is custom, but even there, we
will expand the Body of Knowledge to include PST
Day. A dear friend and leader,
issues and technology. Dale Bissonette of Good Place
Holdings once said as I entered
As for February, what you will find is an excellent the world of transformers
example of the diversity of thought around the
heart of the system, the Transformer. Justin Melroy,
at SDMyers, “You will find
who I had the fortune of having dinner with at a that you will fall in love
recent conference, has presented a great article with transformers before
on deploying condition-based maintenance tech- you know it.” He was right.
nologies to extend the life of renewable energy
assets, which aligns with our sub-topics of green
It kind of sneaks up on you;
energy, DER, and generation. He covered all three not love at first sight, but a
in one article. Great job, Justin! growing understanding of the
importance of transformers
Tony McGrail of Doble tells us “There’s a 70%
Chance Your Transformer Fails”. Yikes! If that
on pretty much every aspect
headline doesn’t grab you then nothing will. of modern-day life.
Speaking of uptime, Traci Hopkins presents a
great perspective on transformer reliability, also
a passion of mine over the past decade. Traci is
also a member of Women in Reliability and Asset But the future is clear: Changes in the grid and in
Management (WIRAM), an organization committed the use of power might bring on some technically
to diversity and inclusion in maintenance and challenging times for practitioners, as adapting to
reliability professions. Traci will represent electric digitalization, EV adoption, cyber-security, asset
power reliability well. management and green energy will be front and
center. And while the transformer will still be the
An interview with Wilfred Breuer of MR is a heart of these changes, it is certain that adjunct
must read as well as articles from members of components will also play a critical part of the
our Technical Advisory Board: Thomas Linn of future, thus the addition of the PST community to
Qualitrol and Maria Lamorey of PPG. our lineup.

With the addition of PST, Transformer Technology For anyone interested in contributing to the
will stand front and center in our development theme and sub-topics for April, please let me
of articles and interviews. I particularly love know at alan.ross@transformer-technology.com.
the cover of this month’s digital issue with the Here are those topics that we will include, but if
transformer clearly identified as the heart of there is a topic that you think fits with our future
the system. focus, please let me know that as well.
Transformer Technology February 2022 13

Issue 18

Coming in April:
New Design and Advances in Technology
• Dry-type Technology
• Changes in Controller and Instrument
Transformer Technology
• Fans & Radiators
• Gauges
• Protection Systems
• Cables and Buss Work

As you can see, the components of electrical

Alan M Ross
systems go well beyond the transformer itself.

Finally, I would be remiss if I didn’t also mention

that in March, we will publish the third digital
magazine for Women in Power Systems (WPS),
something we are tremendously proud to have
launched in 2021. While there are a growing
number of technical associations for women in
engineering, and technical professions, WPS takes
a different approach. While advancing women in
technical roles, we celebrate and profile the com-
plete career woman in our industry, and the reac-
tion to it has been very gratifying. If you would like
to find out how to participate in this community,
please contact Rachel Linke, Chair of the WPS
Steering Committee at rachel.linke@apc.media.

For APC Media, publisher of TT, PST and WPS,

2022 will be the year we will look back upon as
the year we broke through the clutter and became
the recognized leader within all our communities.
The digital revolution is here, and we are proud
to have made that part of our DNA. All the staff
at APC Media are dedicated professionals who
take great satisfaction at being unconditionally
excellent, something I am very grateful to share,
as a foundation of our values.

Please enjoy this issue and please, as always,

connect with us if you would like to be part of
any of our communities or to respond to any of
our authors. For Rachel Linke and me, our email
addresses are above. For any other contact, please
use info@transformer-technology.com.
Curator of the Community
Transformer Technology
Alan M Ross
Editor in Chief

President of EPRA
CRL, CMRP
14 FEATURE
INTERVIEW

Wilfried Breuer
Photo: Maschinenfabrik Reinhausen

Issue 18
Transformer Technology

Managing Director at
Interview with Wilfried Breuer Maschinenfabrik Reinhausen
February 2022
15
16 FEATURE
INTERVIEW

With great pleasure, Transformer Technology is presenting the first part

of an inspiring interview with Wilfried Breuer, the Managing Director at

Maschinenfabrik Reinhausen (MR). Wilfred joined MR in April of 2019.

Prior to that, he had extensive experience in the transmission and distribution

world, including working for Siemens in Thailand and several other countries.

Prior to MR he was with TenneT Holdings in the Netherlands, where he served

on the executive leadership team.

 Transformer Technology February 2022 17

Issue 18

Alan Ross: Wilfried, welcome and thank you for When the opportunity to join MR arose, all those
joining me on this interview. memories of tap changers and transformers
returned. Joining MR and realizing that now it
Wilfried Breuer: It’s my great pleasure, Alan. was my time to “go into the black box” which
I had been learning about so early in my career,

AR You have an incredible background

in technology, especially in the
transmission world. When you were asked to
I must say that was amazing. It’s also amazing
how much innovative potential is still there once
you are inside the company and its expertise.
join MR, obviously they knew you well and they
had an idea of what they were getting. You had Another important element for me is that
an idea of why you would want to take on the I worked in a variety of business models.
role of Managing Director of MR because the When I worked with Siemens, which is a large
company has an incredible pedigree for quality multinational and public-listed company,
and customer satisfaction, being the dominant I had a great pleasure to work literally world-
player in many parts of the industry they play in. wide: in Africa, in Southeast Asia, and with
But when you were asked to do that role, what many different companies. In China, we did
were you trying to accomplish? the first ±800 KV HVDC installation there
and accomplished great things with Chinese

WB I would like to give a couple of two

points to answer that. One is going
way back in my career, when I started to work as
utilities. We also dealt with a lot of issues around
transformers. Then I worked for TenneT, which
is a Dutch state-owned regulated utility, and very
a commissioning engineer. In the late 1980s and much between the energy transition, political
early 1990s, during some activities I performed ambitions and reality of Ohm's law.
at Cahora Bassa, Mozambique, I was introduced
to tap changers. I remember the tap changer And now I work with MR, which is a family-
was something that we were never allowed to owned, very traditional more than 150-year-old
touch, even as a senior commissioning engineer, business. I must say, I don't know a manager who
because it was the Holy Grail of the famous MR. had the pleasure of working in all three, quite
In my very early years, I got to interact with it different governance models: family-owned,
as a special interest of mine. Anything that is mid-size, and global companies that are state
special to an engineer, you always keep it as a owned and regulated, and multinational publicly
special interest, so it was always somewhere on listed. This was something I only recognized after
the back of my mind. I signed the contract with MR. Once I did,
I really enjoyed it. If you had asked me then what
In the years that followed, and as my career my ambition was, it was to go back to a more
matured, I took a direction into management and technology-centered role, which for me, as an
leadership. Transformers, as well as tap changers, engineer, is more exciting than a grid operator
were always a key part of what I was responsible role. With technology driven roles, you are really
for in the HVDC business in Siemens. Converter an inventor, you produce products, type test
transformers are a key element, if not the them, bring them into the market, and you work
most valuable component, of an HVDC system. with customers – that's a different edge.
Likewise, as I moved to TenneT, transformers It’s entrepreneurial. This is something I learned in
played one of the crucial roles in connecting my early days and started to miss it throughout
offshore wind power to the grid. my career, so I used the opportunity to go back
into the technology area and the opportunity to

In my professional career, join MR was highly attractive. I haven't regretted

it for a minute.
I’ve had the pleasure
of working in all three, With technology driven
quite different business roles, you are really an
governance models: family- inventor; you produce
owned, mid-size, and global products, type test them,
state-owned and regulated, bring them into the
Photo: Maschinenfabrik Reinhausen

multinational publicly listed market, and you work

companies. I don't know with customers – that's
many managers who’ve had a different edge. It’s
the same opportunity. entrepreneurial.
18 FEATURE
INTERVIEW

AR I have never heard anyone relate

political reality with Ohm’s Law.
That's very good. You mentioned the Holy Grail.
We have a very high flexibility within our
own workforce to adjust to whatever output
is needed to fulfil the expectation of the
The Reinhausen company is well known for its customers. It is not difficult for us to work extra
culture of excellence and culture of quality, and shifts if it is necessary for the market. It is almost
the load changers are unique in transformers, a given and that is unique because there is an
and they are the Holy Grail. Talk a little bit understanding that everything is paid by the
about that culture. It's been there. It's not that customers who voluntarily decide to use and buy
you are bringing a new culture to MR, but tell us our products or services. They will only do that
a little bit about what you found as you joined because we satisfy their basic needs and their
the company and the culture, what makes it so expectations, and this is what uniquely unites
excellent? the company. It makes us feel like a soccer team
that has learned to play soccer.

AR Well said, you can put a lot of good

players on the soccer field, but they
still don't play a good match if they don’t play
like a team and they haven't practiced. When you
joined MR, you obviously felt that they were a
well working and managed team. Each and every
one is a global star player. Not
only are the Ronaldos there, but
they play the game for a long
time with a high dedication on
customer focus, on technology
understanding and on product
quality. I love the analogy to
soccer/football, the fact that
it's not always the best players
when it's the best team.

I know that most people in our

industry know that product
quality is a dominant culture
at MR.

WB Yes, clearly the depth of the

knowledge and the personal
commitment of most employees to the
product and the company and the willingness
to go the extra mile is exceptional. It was high at You make it your “purpose” to make excellent
TenneT; it was high at Siemens. products. I also know that, especially in North
I wouldn't like to put anyone second, but it's still America, you've added a large service arm of the
quite exceptional and passionate at MR. If you company and your service business is growing.
ask me what makes it exceptional, it is almost How do you maintain that same purpose in
Photo: Maschinenfabrik Reinhausen

a bit religious. For example, what impressed manufacturing as you grow your service business
me is that the demand for tap changers is not within MR?
continuous and we are not a huge company.
We have around 4,000 employees, but still we
manage to cope with the fluctuating demand
for tap changers very well, almost completely
WB That's a very good question and
point. It starts, as many things do
in MR, with the tap changer itself, which is the
without using external/part-time or hired labor. core of the service business of MR. Very special
Transformer Technology February 2022 19

Issue 18

things on the tap changer have to be serviced changers, including the vintage models, which
by a tap changer knowledgeable and trained they must renew every couple of years.
person. In the past, MR only performed the
service because it was expected and requested They must do a practical and theoretical test
by the customer, not as a profit centre. and prove that they are still capable to do the
job. We train them traditionally to take care, by

The tap changer is the core themselves, of the quality because there is no
second technician to say, Did you tighten that
of the service business screw? Did you lose a screw in the tap changer

of MR and doing service and close your eyes to it because nobody will
know about it, because nobody saw it?
on our own tap changes The technicians are exceptionally trained to do

is something that we are the job alone. If I made a comparison not using
soccer this time, I would say, if you were to fly
unique for in the industry. passenger planes with a single pilot, that's the

But our technicians can way we train the people.

do more than just the tap Now we also use the same pedigree for doing

changer because somebody more on the transformer. We say, once our guy is
there who understands the tap changer, he can
who understands the tap do more than just the tap changer. Somebody

changer also understands who understands the tap changer also

understands the rest of the transformer and he
the rest of the transformer. can do a lot of additional things. I know that
from working at TenneT, that staffing is more
Then we realized that we should be the ones and more constrained at the utilities. They have
servicing our own products to ensure the to do more and more work with less people.
quality and long service life. Doing service
on our tap changes is something that we are It is a tendency, not only at TenneT, that if they
unique for in the industry because no customer, can get one service provider who does more
even the highest quality-focused customers, than just a special job, they appreciate that they
will pay two technicians to work on that are not forced due to the lack of own manpower
changer. Our service techs work typically alone. to bundle work. That is exactly where we jump
The customer shows them the transformer, the in and that carries a lot of weight for the U.S.
unit is grounded and switched off from high market, which is a lot more profit-orientated on
voltage and then they get the work permit and the grid operator side. That is our focus coming
basically, they are left alone with the job. from the tap changer: doing more running oil
They are trained in a very unique way as a rigs and oil treatment because the guys who
premium service provider. They must have understand the tap changer understand the
expertise in the different models of the MR tap transformer as a whole.
20 FEATURE
INTERVIEW

AR The first time that I saw Reinhausen

going beyond the Reinhausen tap
changer was with a friend of mine who worked at
a substation area and MR was working on other
companies’ tap changers. I asked him about it and
he said, Well they are cross trained to be able to
handle anybody's tap changer. Now the fact that
you work on the entire transformer answers the
question, why bring in two crews when you can
do it with one? You have tremendous growth in
North America. You've always been the leader
here in the manufacturing end of it and now
you've got tremendous growth in the service end
of it. My assumption is you've now started in the
market. Where do you go from here? What do
you think you want the marketplace to know
about MR services in North America?

We are number one in

servicing tap changers,
and not only the tap
changers manufactured
by MR, and our goal is to
be number one in providing
higher level transformer
service and that is
transformer health and
condition assessment.

WB Our mission there is very clear.

I think we are the number one
when it comes to the service of tap changers,
not only those manufactured by MR, but of
course mostly driven by our large market share
of tap changes in the U.S. market, that makes us
automatically the number one for specialized
service if it's more than just changing the oil and
cleaning it a bit. From there, we also want to be
the number one when it comes to higher level
transformer service. We are not going to aim
to be the market leader for washing, radiators
or changing the paint. I think that is something
where we will also rely on subcontractors. But
when it comes to condition assessment, we have
developed great algorithms with Fleet Scan 2D
and our Tesla Asset Performance Management,
which is just being launched, that take care of
Embedded
data analytics which is where we want to be – the Transformer
first well known practitioner when it comes to
transformer health. We want to be the quality-
Operating
System
Photo: Maschinenfabrik Reinhausen

driven transformer experts, as we are known

for our tap changers, so that our customers
are not under pressure when selling a new
transformer, trying to be credible.

That's our pedigree and it is not a hard job

internally driving it there, but it is of course
Transformer Technology February 2022 21

Issue 18

a hard job when it comes to transformer As a passionate power reliability guy, I realize
service. You are more exposed to that you must have data in order to determine
competition. There are more people with what to do from a service standpoint. That is the
similar knowledge, so it is driving us a bit exponential growth area within North America.
out of our comfort zone in the shadow of
the tap changer.
With ETOS® – our
embedded transformer
AR That is interesting, because when
you go from just the tap changer
into the whole transformer, you are still in
operating system – we are
the maintenance service area. Once you really closing the circle of
start getting into data management and you
get into health management, now you move
new tap changers, creating
into the data, the digital area and that's the data and the protocols
going to be a challenge. But it is also a huge
opportunity because of the pedigree of MR.
through the intelligent
If as a customer you believe the MR pedigree tap changer drive, which
works for manufacturing and now you see it
working for service and maintenance, then
takes care of the entire
you can assume that they are going to bring transformer censoring.
the same quality into the data management
and health management of a transformer,
With this we incorporate
and that’s where the future is. maintenance, service,
condition assessment, and
basically a digital twin.

WB Let me switch here to ETOS® –

which really closes the circle – our
embedded transformer operating system, which
we integrate in the tap changer drive. The tap
changer drive is an unavoidable part of electrics
around the transformer. You have typically three
cubicles: the cooling system, the measurements,
and the tap changer drive unit. ETOS® combines
all the three and enables the operator and the
transformer manufacturer to have basically
a single digitalization through the modern
transformer tap changer drive unit, which you
need anyway. In 2021, we sold close to 2,000 of
these units. So, it is not just in the pilot phase. We
are really closing that circle of new tap changers,
creating the data and creating the protocols
through the intelligent tap changer drive, which
takes care of the entire transformer censoring.
Then what we have is maintenance, service,
condition assessment, and basically a digital
twin – what amount of the life expectancy of the
transformer has been consumed, and what is
really the health condition of the asset.

AR We have come to the end of Part 1 of

our interview with Wilfried Breuer,
which as you just read, is quite amazing. In
our April issue, focusing on the Power System
Technology, we will share Part 2 of our interview
with Wilfried, where he provides his “thought
leadership” on the future of the power industry.

I can guarantee that it will be insightful and

actionable as we navigate the myriad of changes
we are undergoing.
 22

Photo: Shutterstock
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24 CASE STUDY:
TRANSFORMER SAVE

What is a Transformer Save?

by John Eastman

Photo: ZTZ Services

Transformer Technology February 2022 25

Issue 18

What is a transformer save? recommendation on the condition of

an asset was not the
This is not a trick question.
value proposition.
To most readers of this tome,
the answer is simple. A bona- There were utility managers who
understood the potential benefits of
fide transformer "save" is online monitoring yet did not share
when action is taken to protect their operations insight and strategies
with maintenance supervisors.
a transformer, the action This caused the personnel in
being motivated by available maintenance to shun the concept
of online monitoring. Many field
information that is predicting people believed that the monitors
a failure. would replace them, and their jobs
were at risk. Even thirty years ago,
Since the earliest useful micropro- online continuous monitoring of
cessor was available, there have been substation assets had proven to be
many types of condition monitors an excellent tool in the overall scheme
aimed at the utility substation. Most of equipment maintenance, but was
have come and gone and were less not readily accepted.
John Eastman, President of ZTZ Services reliable than the equipment they
International, has 30 years of experience with were monitoring. Many of these had The early adopters of monitoring
substation testing and development of on- some merit but in the early days, the quickly learned that monitoring
line predictive maintenance products. Pre- communication of the data to people systems do not immediately reduce
viously, John was Global Business Manager who cared was not possible. the maintenance budget, but that the
for circuit breaker monitoring products at reverse was true. Monitoring quickly
INCON and Franklin Grid Solutions when he When the SCADA, cell modems, and showed the "bad actors", requiring
was named on two US Patents related to networks became available, then the them to be moved up on the list for
new monitoring concepts. John is a graduate problem of data management became service. Only after the emergent
of the University of Maine in Electrical Engi- an issue. Scanning through data assets were repaired and tested
neering and also holds a Master’s in Teach- produced by monitors by asset SMEs would the O & M expenses gradually
ing and Learning for secondary school math- quickly became very difficult, if not decrease. Maintenance managers
ematics. John is a Senior Member of IEEE. impossible. discovered a "sweet spot" where
deployed monitoring and regular
manual testing worked together to
A bona-fide transformer "save" is when action is produce an overall minimum.

taken to protect a transformer, motivated by available With the refinement of the monitoring
system over decades, the total
information that is predicting a failure. operating costs have decreased
by monitoring justifying itself and
with the forced reduction in manual
Because the lifespan of the early offline testing. Many renewable
monitors, and many companies who energy installations have moved to
produced them, was relatively short, nearly full reliance of online condition
the concepts never reached their full monitoring, thereby making the total
potential of usefulness. expense only the depreciated cost of

The reality of the reliable automatic system is that

calendar-based maintenance is nearly eliminated and

monitoring intersects at a much lower cost point.

The end goal for most was to give the monitoring system. The reality
an actionable signal that an asset of the reliable automatic system is
was in trouble, with a time margin that calendar-based maintenance
to intervene and prevent a failure. is nearly eliminated and monitoring
Continually serving up data for a intersects at a much lower cost point,
"panel of experts" to then give a as shown in Figure 1.
 26 CASE STUDY:
TRANSFORMER SAVE

Figure 1. Additive expenses of calendar-based and condition-based maintenance, past & present

$ O & M Cost Goal, 1995 $ O & M Cost Strategy, 2021

Total Cost Minima 1995

Calendar-based 1995

Condition-based 2021 Total Cost Minima 2021

Condition-based 1995

Calendar-based 2021

Time Time

Regular offline testing is an expensive transformer at a large solar installa- replacement transformer would be
program, one that is increasingly tion in Imperial County, California ten times the value of the transformer
difficult to justify as a regular practice. in May of 2021. For this system, six itself. With the performance history of
Through long-term development and signals given by the transformer C1 over 700 bushing monitors installed
refinement, a monitoring system for test taps, three voltage signals given within the parent utility, trusting the
large power transformers earns trust. by the low-side PTs (Figure 2), and guidance of the monitor was an easy
Industry trust and confidence in three voltage signals given by the decision.
the system comes from reliably high-side CCVTs were connected to
In August, the bushing was tested
with offline techniques. The test
Through long-term development and refinement, confirmed the high power factor and
the bushing was replaced without
a monitoring system for large power transformers earns
incident three weeks later (Figure 6).
trust. The trust and confidence in the system will come Plots of bushing capacitance and
high side imbalance current were
from reliably asserting condition alarms that enable stable since the monitor installation,
transformer saves. showing the likelihood that the H1
bushing had high power factor when
the transformer was commissioned,
asserting condition alarms that the 12-channel monitoring system but was not detected with offline test
enable transformer saves. With this (Figure 3). techniques.
trust, reliance is comfortably placed
on the automatic system, not the The use of all twelve phasor measure- At a power plant in Eastern Europe,
"panel of experts", buttressed by ments makes for an extremely robust bushing monitoring was added to the
labor-intensive offline testing with system with very high signal-to-noise high-side bushings of a 17-year-old
expensive equipment. ratio. By using measured system 270 MVA GSU in December of 2015.
phasor quantities, the bushing attri- Six phasor inputs were used; three
Below is a tale of two cities. In one city, butes can be very accurately known. high side C1 test tap connections
soon after installation of the bushing and three CCVT inputs. Two months
monitoring system, a bushing was Within a few days, it was quite after installation, the data showed
singled-out as having a power factor apparent there was a problem with the C1 from H2 (blue trace) above
of more the twice the nameplate the H1 high side bushing, with power the others by 0.5% (Figure 7). The
value. With a spare transformer factor nearing three times nameplate power factor data (Figure 8), shows
being located 1,800 miles away, a (Figure 4). Phases H2 and H3 showed power factor of H2 peaking at 1.5%
replacement would take at least four stable power factor, essentially (red trace).
weeks. The operator of the solar at nameplate values (Figure 5).
farm prudently replaced the bushing Because of the heavy load cycle, this Further increasing confidence, the
during a nighttime outage, with no transformer was classified as being polar plot of the high side leakage
loss of revenue. In another city, the applied to "rough service". The high imbalance current (Figure 9) shows
monitoring system clearly asserted power factor reading put it beyond steady increase, showing strong
evidence, with high confidence, that the limit for any "watch list" but was polarization.
a bushing was in trouble and the classified as "unstable", in danger of
trends indicated an imminent failure failure. Four months from installation, data
Photo: ZTZ Services

was likely. The operator delayed action. shows worsening conditions. C1 at

With "green" renewable energy 111% (Figure 10), PF at 8% (Figure 11),
A bushing monitoring system was selling for a premium locally, the and leakage current imbalance
installed on the main step-up power revenue loss while waiting for the of 8.0% (Figure 12).
Transformer Technology February 2022 27

Issue 18

Figure 2. Bushing sensors installed on low-side bushings Figure 5. High-side percent power factor for three months
since monitor installation

1.5

PF [%]
H1_PF

1 H2_PF

H3_PF

0.5

0
June 2021 July 2021 August 2021

Figure 3. Two six-channel bushing monitors

are installed beside the transformer Figure 6. Night time H1 bushing replacement

Figure 7. C1 percentage above nominal of high-side bushings,

Figure 4. High-side bushing nameplate showing factory test data two month plot
28 CASE STUDY:
TRANSFORMER SAVE

Figure 8. Percent power factor data of high side bushings, Figure 11. Percent power factor data of high side bushings,
two month plot four month plot

Figure 9. Polar plot of leakage current imbalance, two month plot Figure 12. Polar plot of leakage current imbalance,
four month plot

Figure 10. C1 percentage above nominal of high side bushings, Figure 13. Final death rattle of the H2 bushing, showing last
four month plot measurement of C1
Photo: ZTZ Services
Transformer Technology February 2022 29

Issue 18

Figure 14. Station security camera view of exploding H2 bushing

Figure 15. H2 bushing debris found in yard showing failed capacitive layers

In May of 2016, it was advised that Of course, most commercial monitoring valuable nuances. Management of
the transformer be taken immediately systems can be made to work well at external electrical noise must be
out of service for testing. Because time of commissioning, but only the in the heart of the system, as part
an outage was planned within five highly developed system, well installed, of the wholistic design, not as an
weeks, the owner decided to wait until will last for decades. afterthought.
then. Two days before the outage,
the bushing exploded (Figure 14). The hardware requirements for utility The end product is reliable supervision
The final C1 measurement of H2 use are different than for consumer of expensive transformer assets
was 114% (Figure 13) and 8% power electronics. High refinement includes which are becoming more and more
factor. In the last moment before immunity to cyberattack, continuing valuable as replacements have ever
failure, the big increase of C1 can compatibility as the PC operating longer lead times.
be observed, caused by break of system landscape changes, and
insulation layers between metal foils the continued draw on IT resources The failure above was only allowed to
in bushing condenser core (Figure 15). for software patches and "updates" happen by human interaction. Waiting
made unnecessary. for the response from a "panel of
A monitoring system giving asset experts" is no longer required as
condition guidance with very high Improvements applied to algorithms, an arbiter and can be an expensive
confidence is something that is methods, signal fidelity, and noise liability, especially in the case of a
continually improved over decades in rejection give the highest sensitivity rapidly developing problem.
thousands of field installations. Sensors to changes and fastest determination
and other hardware are required to be of problems. Noise filtering after the
made with high precision and material measurements are not a panacea.
quality, with no system calibration Signal filters with long time constants The actual failure event was captured
requirement for the life of the system. slow the decision response and hide on video, and you can see it here.
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32 ADVERTORIAL

INTEGRATED FOR FACTORY

SOLUTIONS FROM AND LABORATORY
POWER DIAGNOSTIX PARTIAL DISCHARGE
BY MEGGER TESTING

Not only does Power Diagnostix

have a large portfolio for
such instruments, but it also
Power Diagnostix is a provider of assists in providing corresponding
instruments designed to detect interpretation and diagnostics
partial discharge (PD) in electrical of insulation conditions and
insulation before the system offers expert technical
is compromised. services.
 Transformer Technology February 2022 33

Issue 18

In 1986, Power Diagnostix was founded in Aachen, Germany to provide solutions One of the most cherished
for identifying potential defects in insulation systems before a failure occurs.
It sought to achieve this primarily by offering partial discharge measuring philosophies of Power
instruments, as well as with tan delta and high voltage testing equipment. Diagnostix by Megger is to be
In June 2019, Power Diagnostix joined the Megger group. Although Megger customer-oriented and tackle
has had one of the largest product portfolios in the electrical testing industry the issue of PD measurement
for over a century, it identified Power Diagnostix as the perfect addition to the
Megger team and brought it on board. by working closely with its
customers to learn about their
PD is a precursor to serious insulation degradation which can lead to failures
of electrical components. PD can be caused by imperfections in the insulation challenges and needs.
system as well as by external factors. Once partial discharge has occurred, it
steadily increases over time as the insulation continues to degrade, ultimately
leading to irreversible damage and failure. Therefore, it is necessary to detect
PD as soon as possible, which can be done using various measurement
techniques, such as measuring charge in various frequency ranges or by
acoustic detection.

Power Diagnostix HV test lab in Aachen Germany, used for research, development, training, and test services

One of the most cherished philosophies of Power Diagnostix by Megger is to

be customer-oriented and as such, it tackles the issue of PD measurement by
working closely with its customers to learn about their challenges and needs.
In this way, Power Diagnostix serves, as a partner, to implement solutions,
closely cooperating with its customers through consulting, commissioning, and
after-sales support. This enables engineers to stay up-to-date on current trends
and industry requests to drive the development and improvement of products
and services.

Power Diagnostix serves, From portable testing instruments for field use, to permanently installed
monitoring systems for a variety of electrical applications, all solutions are
as a partner, to implement configured specifically based on the customer’s needs. This is especially
solutions, closely cooperating the case when it comes to solutions for high voltage testing laboratories, as
each project is custom designed with the customer. These solutions are often
with its customers through supplied for use in production line testing, factory acceptance testing (FAT), or
consulting, commissioning, quality control after repairs. Given this range of solutions for power transformers
and other electrical applications, it is not surprising that Power Diagnostix
and after-sales support. caters to a wide variety of customer industries, including Original Equipment
Manufacturers (OEMs), testing and calibration laboratories, repair shops, and
research and education institutions.
Photo: Megger
34 ADVERTORIAL

Modular concept for laboratory and factory testing applications Power Diagnostix is more
than a manufacturer of partial
Increased testing demands from customers drive the need for time saving,
automation, and improved performance and functionality. Modular solutions discharge testing instruments.
from Power Diagnostix allow testing laboratories to extend their testing capacity,
We are also involved with
enhance their technical capabilities, and modernise their equipment to meet
customer’s needs and to maintain efficiency. the development, design,
configuration, and integration
Generally, laboratory applications consist of several main components: partial
discharge measuring instrument and associated accessories, high voltage power of the full system, and
supply, high voltage control unit, software for control, measurement and reporting,
provide customer training and
and, most importantly, safety provisions. For each project, components are
configured specifically based on voltage level, objects being tested, test procedure, commissioning.
number of measurement channels, noise conditions, desired level of automation,
and more.

As an example, a typical testing configuration for PD quality assurance and

quality control in the manufacturing of products such as bushings or voltage
transformers includes:
• Single PD measurement channel
• Coupling capacitor, quadrupole, and pre-amplifier
• Noise gating
• Optional 4 or 12 channel multiplexer for testing multiple samples
• PD spectrum analysis option

For production line or factory accep-

tance testing of samples such as
bushings or voltage transformers, the
ICMcompact is typically the preferred
instrument for partial discharge test-
ing. This instrument allows testing ac-
cording to IEC 60270, easy setup,
and can adapt to specific test appli-
cations and interference situations
through various accessories. Additi-
onally, ICMcompact can be integrated
into an automated test bench with
other test equipment and automa- The ICMcompact shown in two of three available housing versions
tion software as described further in
this article.
A typical configuration for power transformer factory acceptance testing of par-
tial discharge includes:
• 6 to 10 parallel PD measurement channels
• Coupling capacitors, quadrupoles, and pre-amplifiers
• Noise gating
• Phase Resolved Partial Discharge (PRPD) analysis software
• Acceptance test reporting software

Most commonly, when testing three-phase power transformers, an instrument

with multiple measurement channels is used. This allows for testing all three
phases of the primary and secondary windings simultaneously (6 or 8 channels
with neutral bushings). Measuring PD in parallel on all bushings saves the user
time with lead connections, accessory configuration and calibration, and total
measurement duration. Additional channels can be used for acoustic or Ultra
High Frequency (UHF) PD sensors or noise gating (filtering) via a high frequency
current transformer or noise antenna, which ensures accurate and sensitive
measurements. This saves time and effort and allows better comparison of PD
results between phases.
 Transformer Technology February 2022 35

Issue 18

For three-phase power transformer factory acceptance testing, a multi-channel

ICMsystem is preferably used due to enhanced tools for in-depth analysis. With
its true parallel PD acquisition of up to ten channels, the overall testing period
is substantially shortened by features such the automatic calibration cross-
coupling matrix. ICMsystem offers both - narrow and wide band PD pattern
acquisition, according to IEC 60270. The instrument comes with an embedded
spectrum analyser for advanced PD analysis in frequency domain. Moreover, it
is an excellent tool to use in case of noisy test environments. Additionally,
acoustic sensors can be interfaced with ICMsystem for PD fault localisation.

ICMsystem desktop version

Automation for laboratory and factory acceptance testing

Different levels of automation can be provided depending on the test. In the

case of full production testing, a high level of automation and a simple go/
no-go decision is required. This enables testing technicians to be trained for
standardised working procedures during or after production so that in-depth PD
knowledge or detailed result analysis is not necessary for daily work.

Alternatively, manual control offers a higher level of flexibility when testing samples
or sample variants during development. Automated laboratory solutions typically
start with a configuration of ICMcompact (PD measuring device), HVcontrol (High
voltage test control unit), a testing transformer, and noise filtering hardware.
These components are fully integrated with the HVpilot software so that users
can benefit from one automated interface for voltage control including automated
ramp sequences, PD measurements, and test reporting. Additionally, TDAcompact
is optionally integrated for tan delta testing.

Example functional diagram of an integrated test lab setup from Power Diagnostix by Megger
Photo: Megger
36 ADVERTORIAL

The system is always integrated with a safety interlock with HVcontrol, horns
and/or lamps, as well as manual and automatic earthing discharge rods. These
provisions are mandatory in order to prevent exposure of testing personnel to
hazardous voltages.

Most customers for this type of application prefer the 19” rack-mountable version
for the measuring and control instruments that are integrated permanently into
the test bench. This provides convenience for laboratory testing, especially
where test routines and samples are repetitive. Cables, instruments, sensors,
and other accessories can be fixed installed to prevent loss or damage and to
save time with connections and configurations. Optionally, a dedicated built-in
computer results in less time spent configuring software or troubleshooting IT
issues. An additional advantage for test bench integration is that test sequences
and results are stored in one central location.

Users who require portability and field use can be provided with test instruments
in rugged portable or desktop enclosures as a suitable alternative.

ICMcompact embedded in a control desk with additional control hardware

Additional integration options

High voltage test chambers (HVTC) can be added to the configuration to provide
isolation from noisy conditions and are suitable for PD testing according to
international standards. These solutions also allow owners to save space for
their testing setup in comparison to an open area where distance, fencing, and
isolation are required for safety purposes during high voltage testing.

Tan delta (dissipation factor) measurement is an additional method used to

assess the condition of an insulation system for transformers and other electrical
equipment. The TDAcompact from Power Diagnostix can be also integrated into
such laboratory setups for this purpose. This results in additional convenience
and saves time as users can conduct pre-programmed test sequences for
voltage step, PD, and tan delta all simultaneously with integrated software from
one interface.
 Transformer Technology February 2022 37

Issue 18

Due to the modular approach, customers have the ability to choose many
parameters to fulfill their current testing needs. This provides flexibility with
voltage levels, type of test instruments, level of automation, and optional
hardware and software features. Also, upgrading and retrofitting in the future is
possible as needs change.

Supplementing laboratory capabilities with mobile support

Power Diagnostix isn’t just a manufacturer of partial discharge testing instruments.

Engineers are also involved with the development, design, configuration, and
integration of the full system. Additionally, Power Diagnostix provides customer
training and commissioning. After the system is installed and in service, the job
does not stop there.

Power Diagnostix mobile test system

From portable testing Service Engineers are happy to offer consultation, result analysis, and mea-
surement support. If a testing laboratory faces a job that exceeds their hardware
instruments for field use, or manpower capabilities, experts from the Service Department are available for
to permanently installed on-site testing using mobile test laboratories.
monitoring systems for Whether it’s to support factory acceptance testing for unusual or challenging
a variety of electrical cases, site acceptance testing at the equipment owner’s site, or PD localisation
while the equipment is in operation, Power Diagnostix Service is the trusted partner
applications, all solutions for PD for your power transformers and other applications. We travel Europe-wide
are configured specifically to your site with our mobile test systems. Besides PD, we are also happy to offer
additional diagnostic tests for your applications, such as three-phase induced
based on the customer’s tests (up to 90 kV), applied voltage (up to 500 kV), tan delta/loss factor, ratio tests,
needs. winding tests, insulation tests, and more.
Photo: Megger
38 TECHNICAL
ADVISORS’ COLUMN:
TONY MCGRAIL

That’s a prediction (or The only ways to get this How can we check the poor prediction – which
forecast) which can’t be type of prediction wrong accuracy of the prediction we can check through
wrong! are to say something will if the event only happens repeated rolls. We can roll
definitely 100% happen, once? It’s not like repeated the dice many times, but
If we say there’s a 70% and it doesn’t, or say that rolls of a dice, which we we can’t rerun the year
chance of failure as an out- something definitely 100% can predict with some many times. What we
come and the transformer will NOT happen, but it statistical accuracy. If I roll can do is look at similar
fails, then the outcome falls does [1]. But avoid the two a standard, fair, 6-sided situations, in this case
in the 70%, and if it doesn’t definite statements, and dice, the chances of rolling other transformers, and see
fail the outcome falls in the any other version of the a 4 are 1 in 6 (16.67%). If I how well our predictions
30%. We’re covered come prediction cannot be predict I’ll get a 4, say, 50% of failure probability stand
what may. wrong. of the time, that’s likely a up in each case: compare

There’s a 70% chance

of your transformer
failing in the next year Tony McGrail is Doble Engineering Company’s
Solutions Director for Asset Management &
Monitoring Technology, providing condition,
criticality and risk analysis for utility compa-
a) What is the expected value of a dice roll – the
nies. Previously Tony has spent over 10 years
QUIZ?

mean of many throws?

with National Grid in the UK and the US; he has
b) If there’s a 10% chance of an event happening been both a substation equipment specialist
in any 1 year, how likely is the event occurring and subsequently substation asset manager,
at least once in a ten-year period? identifying risks and opportunities for invest-
c) How many people need to gather such that ment in an aged infrastructure. Tony is a Fel-
two of them are likely to have the same low of the IET, a member of the IEEE, CIGRE,
birthday (day/month not year)? ASTM, ISO and the IAM, and is currently active
d) How many need to gather such on the Doble Client Committee on Asset and
that 1 of them is likely to have Maintenance Management and a contributor
the same birthday as you? to SFRA, Condition Monitoring and Asset Man-
agement standards. His initial degree was in
QUESTIONS Physics, supplemented by an MS and a PhD in
EE followed by an MBA.
Transformer Technology February 2022 39

Issue 18

the estimated probability Some years ago, the happened. It does this If you have an interest in
of failure with the actual weather forecasting folks through a mean square this topic, please contact
outcome at the end of the put together a means to error, with the lower the the author!
year for each transformer. measure the accuracy of Brier score the better the
If I estimate a 5% chance predictions or forecasts, set of forecast [2]. When working with proba-
of failure for a particular called a Brier Score [2]. The same approach would bilities I recommend check-
transformer and it does The score tells you how apply to transformer failure ing results with an expert
fail, I’m out by 95%. But well your predicted forecast probabilities and can be as things can get compli-
how do we rate the overall for rain, or failure, or used to check the accuracy cated and can sometimes
prediction accuracy across whatever, across a number of the forecast; and is be counter-intuitive [3].
the population? We can of locations and times something we’re working Some quiz questions may
look to weather forecasters! relates to what actually on at present. help illustrate.

QUIZ!
a) 3.5, but that’s not going to be something you’d
References
[1] Barbara Mellers in “Rational
actually roll with a fair 6-sided dice Soothsaying”, https://www.
bbc.co.uk/programmes/
b) Just over 65% – probabilities don’t just add up
m00132v9
year-on-year, it’s more complicated!
[2] https://en.wikipedia.org/wiki/
c) 23 people – which seems a remarkably small Brier_score
crowd for the chance of a birthday [3] How Juries are Fooled by
coincidence to be greater
Statistics, Peter Donnelly, TED
than 50%!
Talk, 2007
d) 253 people – for the chance to
be greater than 50%, not the
183 often suggested… Acknowledgement
Thanks to Rhonda, Richard and
ANSWERS Vanessa for their suggestions.
40 ELECTRICAL
SAFETY

Tragedy & Expense:

The High Cost of Low
Electrical Safety
by Michael Riccio

Photo: IRISS
Transformer Technology February 2022 41

Issue 18

The electrical industry Every year, OSHA puts out their list
is one of the most

E
of top 10 violations, and every year
dangerous work the electrical industry is one of the
environments for big “winners”. To make things worse,
employees. The risk of these are not new violations making
very year, OSHA
injuries and fatalities is the list because highlighting the puts out their
high due to the nature of previous year’s violations led to vast,
the work and the amount industry-wide corrections. It’s the
list of top 10
of interaction workers same offenses year after year. Patrick violations, and
have with dangerous Kapust of the National Safety Council
equipment and conditions. stated at the 2019 NSC Expo “these
every year the electrical
Electrical incidents are common violations we’re finding industry is one of the big
happen daily, putting – they’ve been in place for a lot of
lives and operational years. The answers are out there, and
“winners”, with the same
continuity at risk. employers shouldn’t feel like these offenses year after year.
However, there are ways are complex issues.”
companies can reduce Whether or not the responsibilities
the occurrence of these Mr. Kapust is correct, the issues of workers and management alike
incidents and protect aren’t complex. But unfortunately, are strictly adhered to also has
everyone concerned from multiple daily news stories reflect major financial implications, not
the physical, financial, and excessive failures around the world just from an operational and safety
statutory consequences. to keep workers, customers, and the standpoint, but from insurance rates
general public safe. A great example and litigation fees/judgements as
of these failures is that during 2021’s well. Statistics are heavily studied
“National Electrical Safety Month” in the electrical industry, as safety
there were multiple reported injury should be the priority for everyone
events every day of the month. These involved. Gambling with this isn’t just
injuries reflect the neglected roles by dangerous, it’s expensive.
both management and workers in
the safety process. Recently, charges were brought
against a utility company over the
Under NFPA 70E, both employers death of a power station worker in
and employees have very defined 2018. During a scheduled routine
responsibilities as members of maintenance, where the employee
Michael Riccio his the Global Marketing a team tasked with keeping safe was found to be doing his job exactly
Manager for IRISS Group, providing market/ practices and procedures in mind as trained, he was severely burned by
industry analysis, support, and educational while accomplishing their tasks. an arc flash and later passed away
insights to customers, distributors, and sales At the heart of NFPA 70E and OSHA at the hospital, and investigations
worldwide. He is a Certified Reliability Leader, initiatives are concepts such as the brought about three separate charges
a CAT-1 IRT thermographer, and is a contrib- Hierarchy of Control. This concept against the utility.
uting writer to other industry publications attempts to mitigate risk wherever
such as the National Safety Council’s Health possible, preferring the elimination The loss of life is beyond tragic,
& Safety Magazine. of hazards as the ultimate goal. though not at all a rare case.
Unfortunately for companies who
Hierarchy of Controls have these fatalities and injuries as
a result of electrical accidents, this is
just the beginning of their problems.
OSHA fines can reach deep into the
pockets of a company, of hundreds of
thousands of dollars in possible costs.
The wrongful death cases or lengthy
Worker’s Comp litigation, as well as
associated personnel-driven costs, will
most likely lead to a major financial
impact on the company. According to
Falcon Power Consultants, 5-10 arc
flash incidents occur every day in the
United States, resulting in 1-2 deaths
per day. The average litigation costs
for a general industry accident range
from $10M to $15M.
42 ELECTRICAL
SAFETY

as an arc flash add to this with the

cost of repair or replacement of the
asset(s) involved. Additional costs
may also come into play with time
required for staff to go through new or
refresher safety training and replacing
the injured parties with other workers
will involve more expense and time.

A
study by
Aberdeen
Research
found 82%
of companies that
experienced unplanned
downtime lost an
average of $2 million in
revenue.
Not only does it damage a company’s
operational and fiscal health, but

A
also its reputation and earnings
potential with current or prospective
ccording to three years of claim history (not customers. What it comes down to
including the most recent policy year), is simple: not only does risk lead to
Falcon Power your premium can either go up or great tragedy, but also great expense.
Consultants, down.
5-10 arc flash The issue, then, is to figure out how
With over 3,700 non-fatal electrical to remove or minimize human error
incidents occur every accident injuries occurring each year, and human risk wherever possible.
day in the United States, the average cost of hospitalization While that is a difficult task for most
for electrical accidents ranges industries, the electrical industry
resulting in one-two from $200,000 to over $1 million faces a much steeper challenge.
deaths per day. The (according to the Workplace Safety Risk-based activity is the driver for
Awareness Council). Once out of the incident, injury, and fatality. In the
average litigation costs hospital, as part of the fallout from electrical world, these behaviors are
for a general industry

R
these claims, the time away from 30 times more likely to lead to death.
work averages 8-12 months. These
accident range from incidents will not affect the premium
$10M to $15M. calculations in a positive way, nor will
isk-based
it look favorable for the manager to activity is
Work Comp claims and insurance executive management or help the
expenses bring another level of company’s fiscal health.
the driver
cost. One of the main factors that for incident,
determines a company’s workers’ Operationally, things don’t get better
compensation premium is referred in these situations. Unplanned
injury, and fatality.
to as loss history. This is an analysis downtime from an electrical incident By minimizing the
of insurance losses associated is expensive on the operational
with workers’ compensation claims level, such as in a data center where
interaction between
and plays a key role in causing an estimates show each minute down asset and personnel
increase in premiums. Underwriters averages $8000 in loss. A study
calculate premiums using these by Aberdeen Research found 82%
through technology
numbers to determine a company’s of companies that experienced and structure, the odds
experience modification factor unplanned downtime lost an average
of incidents occurring
Photo: IRISS

(or e-mod). Depending on the results of $2 million in revenue. Physical

of their assessment, which considers damage resulting from incidents such drops sharply.
Transformer Technology February 2022 43

Issue 18

The simple answer is to eliminate Switching to a condition-based issue, the use of inspection windows
the risks completely. The best option program leads to asset interaction on the asset allows a safe, efficient
is to remove the human factor from only occurring when it is absolutely method of inspecting and assessing
as many threats as possible. This is necessary. This involves remote any possible issue in an energized
not to say that humans should be monitoring of asset health, safe and condition. Once solely designed for
replaced with technology, but instead guarded inspections of equipment at thermographic inspections using
we should eliminate the numerous full load (overcoming the OSHA Top infrared cameras, advancements
risk-based behaviors that occur in Ten violation of machine guarding), in manufacturing have led to the
the workplace through technology. and the trending/analysis of collected inclusion of ports that allow for
The entire work environment must data to create a clearer picture of an ultrasound and partial discharge
be approached as “function follows asset’s operational health. technologies to be incorporated into
form”. This means the physical the inspection. Visual, infrared and
environment drives the operational With the use of an online monitoring ultrasound inspections can be done
environment, with technology system on electrical equipment, simultaneously by a single employee.
guarding and assisting the worker. asset conditions can be continually
collected, trended, and assessed. This design protects inspectors from
Traditional electrical maintenance Monitors feed data through a gateway arc flash/electrocution risk, removes
practices tend to rely on calendar- to software and apps, allowing the the need for bulky and expensive
based models that include intrusive information to be continuously personal protective equipment,
and dangerous activities that put both accessed from workstations and and allows the inspection to be
workers and assets at risk. From the mobile devices. When the asset accomplished more efficiently. Not
equipment and operations side, every condition data exceeds the custom only does this represent a significant
time an unnecessary time-based task parameters, alarms can notify process improvement driven by
is completed the infant mortality clock electrical technicians of a possible original design, but it also falls in
is reset and the risk of failure increases. issue that may require inspection. line with the most recent NFPA 70E
These tasks also increase the odds Keeping human interaction with updates and continues to protect
of a worker experiencing risk while equipment to only instances where critical assets from human interaction/
performing their duties. By minimizing inspections of potential faults are mistakes that may cause failure.
the interaction between asset and deemed necessary minimizes
personnel through technology and workers’ exposure to risk. The data collected during inspection
structure, the odds of incidents can be stored through intelligent
occurring drops sharply. As do the Once the wireless monitoring system asset management tags attached to
odds of a very expensive outcome. notifies technicians of a possible the pre-installed inspection windows.

Importance of Electrical Safety

44 ELECTRICAL
SAFETY

From the asset location, information The proper tools are only as useful The physical environment of any
can be transmitted into a dashboard as the hands wielding them. Shifting factory, plant, facility, etc. is the
system accessible from workstations to an engineered reliability system setting where risk-based behaviors
and mobile devices. Customizable for the electrical maintenance team take place, with both machinery and
routes can be established before, and means training new and veteran staff power systems posing the highest
condition reports generated after, data alike. The use of technology allows threats to worker safety. Structuring
analysis to further increase efficiency. single individuals to accomplish safe out hazards through technology
These design aspects allow managers inspection and maintenance tasks drastically reduces the opportunities
to assess operations and limit the with minimal training. Online learning for incidents/injuries/fatalities to
amount of “scheduled exposure to systems offer on-demand educational occur, and as an added bonus,
risk” that so many archaic, yet still and training resources that teach the increases the reliability of assets and
employed, systems cause. use of these specific technologies. efficiency of the team.

Photo: IRISS
Transformer Technology February 2022 45

Issue 18

K
eeping human
interaction with
equipment to only
instances where
inspections of potential
faults are deemed
necessary will minimize
workers’ exposure to risk.
46 ADVERTORIAL

DIGITAL TWIN A SIGNIFICANT

TECHNOLOGY OF STEP IN THE
SENSFORMER™ DIGITALIZATION OF
ADVANCED TRANSFORMERS

Digitalization of transformers will First-of-its kind digital twin

be a decisive step for grid operators technology from Siemens Energy
in managing the current and future offers special advantages compared
challenges. to conventional solutions.

It enables grid operators to make data-driven

decisions, increase the reliability and productivity of
transformers and minimize risks using the results of
a thermo-hydraulic calculation model.

Digitalization helps operators to manage the growing

complexity of grids with versatile, intelligent assets, capable
of processing large volumes of data and recommending which
optimum course of action to take.
 Transformer Technology February 2022 47

Issue 18

Sensformer™ Advanced from Siemens Energy adds a digital layer of operational

transparency to power transformers

The world is changing – data has become an inevitable but essential part of The Siemens Energy digital twin tech-
everyday life. In 2018, Sensformer™ was introduced as Siemens Energy’s first nology is also the first of its kind to
digitally enabled transformer, providing real-time information about the trans- transfer common technology assets
former’s performance and status. Since then, various other products have joined into the new interconnected world,
the Sensproducts™ portfolio (e.g., digitally enabled circuit breakers and gas- where asset health status as well as
insulated switchgears). Challenges, such as the increasing global demand for dynamic and volatile condition assess-
electricity, which needs to be met with the existing fleet of grid installations, open ment are key and available at any time
up opportunities for new solutions. With the aim of increasing transferred energy and any place.
and optimizing transformer lifetime based on real-time information, Siemens
Energy has launched Sensformer™ Advanced with digital twin technology.

Heat sources of a transformer build a thermo-hydraulic model including the oil flow

Siemens Energy uses a thermo-hydraulic calculation approach which provides

an accurate and complete thermal image of a transformer

The digital twin is a virtual replication of each single transformer, established on

the basis of its design data. This computational duplication is based on operational
data like winding currents, cooling equipment status and ambient temperatures –
either in real time to produce an online simulation, or even in advance to simulate
potential transformer operation states. The thermo-hydraulic model computes
the electrical loss distribution within the transformer’s active part. The model
takes into account the actual transformer ratio, while considering the tap position.
It distinguishes between ohmic and eddy losses with their respective temperature
dependency, as a specific feature of the loss calculation. The model is based on
real material characteristics like masses and heat capacities of conductive and
insulating materials, to allow calculation of the dynamic temperature processes
during operation. The hydraulic resistances of certain transformer components
such as the core, windings, radiators, etc. are defined as parameters in the model,
and the oil flow is determined by the buoyancy forces and optionally additional
pump pressures, if pumps are present. Consequently, and contrary to more
simplified models, the Siemens Energy digital twin does not use fixed thermal time
constants, but can consider the relevant dynamic heat transfer mechanisms in the
transformer. Based on this thermo-hydraulic approach, the heat transfer equations
can take into account the relevant physical quantities like oil temperature, oil flow,
losses, etc. Consideration of the oil flow distribution and heat transfer mechanisms
results in a thermal transformer model which covers different cooling modes, as
well as the transient behavior between these modes, like xDAF to xNAF or xNAN
Photo: Siemens Energy

(note: with x being used for O or K rating). The result is a precise temperature
calculation. Moreover, due to the multi-mass approach linked to the oil flow, it is
possible to couple the model with other important physical transformer models,
for example for a moisture calculation.
48 ADVERTORIAL

Customers can optimize transformer operations based on digital twin calculations

Currently, the digital twin model in Sensformer™ Advanced can be used for three Customer benefits:
scenarios: • Real-time information
1. for simulating any load and ambient temperature cycle for 24 hours into the future available anywhere and
2. for determining permissible overload with defined boundary conditions anytime
3. for automatically calculating the relative aging of the transformer
• Notification app to
This means the customer gains new insights into different transformer conditions. minimize risks and
When simulating a load cycle, customers can define values for various operational
data for the next 24 hours, which at the same time represent the model inputs improve environmental
(e.g., transformer load, tap position or ambient temperature). The thermo-hy- protection
draulic calculation model then simulates the temperature behavior for the
transformer top oil temperature, as well as the winding hotspots for the coming • Analytics-based and data-
24 hours for the assumed load cycle, starting with the actual thermal transformer driven decision-making
condition. Another insight is the continuously determined and visualized maximum
permissible transformer’s overload capability for the next 30 to 60 minutes. • Improved operational
Different boundary conditions such as aging values (loss of life) or temperature reliability and
limits can be considered in the overload calculation. Finally, automatic calculation
of the relative transformer insulation aging is also available. This loss of insulation productivity
life is calculated according to the IEC loading guide formulas over the previous • Condition-based
24 hours, the previous 30 days, and since the Sensformer™ Advanced application
was commissioned. This provides a real life-time assessment of the transformer maintenance
and the option of comparing the thermal load of several different transformers. • Data download for
Design-specific modelling based on reporting
customer-specific design • High-level certified
Each transformer has its individual security and cyber
digital twin model. Depending on the security standard
design of the transformer (oil natural
vs. oil directed, number of windings, co-
olers, fans etc.), a particular model struc-
ture is created which is parameterized The main difference between conventional models and Siemens Energy digital
with specific design information. The twin technology is the use of a multi-mass approach
required model parameters such as
oil volume, heat capacities, insulation The main difference between simplified standard thermal models and the Siemens
thicknesses, ohmic resistances and Energy digital twin is the multi-mass approach. Simple models often consider only
hydraulic resistances, are determined the thermal behavior of a single winding for a specific tap position and specific
from the real data of the transformer. cooling mode. It is only possible to simulate for this winding its hotspot temperature
Dimensions, materials, thermal data, for load and ambient changes. However, this is clearly less accurate and not
fan and pump characteristics and many sufficient in terms of real thermal stress within a transformer, as the position of
more play a significant role. The thermo- the highest temperature can vary from one winding to another when a transformer
hydraulic calculation is therefore tai- is operated at a different tap position. In contrast, the Siemens Energy digital twin
lored to each transformer design, and covers all windings and the possible cooling modes of the transformer. Depending
it can consequently predict the over- on the tap position, the loss distribution occurring in the windings is calculated and
load capacity, aging and service require- consequently the hotspot in the transformer can be continuously calculated. The
ments with a high level of accuracy. Siemens Energy digital twin is based on a multi-mass model, which also includes
the oil flow. In the near future, further other essential physical relationships will
be considered, like moisture calculation and insulation degradation. Only these
models will really constitute a complete digital twin of a transformer which will
allow a very deep insight into the transformer.

The temperature behavior is an essential part of the digital twin technology,

where the comparison of measured and calculated values during operation gives
an insight into the quality of the calculation model. The diagram on the next page
shows such a comparison for an oil natural cooled medium power transformer over
Photo: Siemens Energy

a certain period of time. The most accurate correlation between the measured and
calculated top oil temperature of the transformer is found in the case of the digital
twin, whereas the conventional IEC standard model results in higher deviations
and consequently less accurate estimated conditions.
 Transformer Technology February 2022 49

Issue 18

Customers have 24/7 access to Sensformer™ Advanced applications and can

use the information provided to cut OPEX

Using the digital twin technology, the Sensformer™ Advanced provides a digitalized
solution for different scenarios. The Sensformer™ Advanced web application pro-
vides grid operators with 24/7 access and increases transparency in the perfor-
mance of the transformers. Early warnings and push notifications on mobile
devices can further help to alert operators when situations are getting critical
(e.g. oil loss, excessive temperatures, etc.). The information provided by
Sensformer™ Advanced applications can be used to cut maintenance costs by
reducing man-hours at the facility thanks to condition-based maintenance and
the prevention of unscheduled outages. Moreover, active load prediction and the
aging trending and projection supports the lifetime planning of transformers,
which is beneficial for long-term grid modernization. Comprehensive visualization
tools support further decision-making in the evaluation of equipment conditions.

Comparison of different calculation methods for transformer top oil temperature

Temperature in °C
45
Real data
40
Digital twin calculation
35 Conventional IEC calculation
30

25

20

15

10

0
1 2 3 4 5 6 7 8 9 10 Time in days

Investing in digitalized equipment is an essential step forward

Author | Department
DD The worldwide increase in electricity demand as well as the need for sustainable
Restricted © Siemens Energy, 202
measures to stabilize grids due to an increase in renewable power generation call
for digital solutions. Sensformer™ Advanced, based on the Siemens Energy digital
twin technology, provides the customer with real-time information on the status
of the transformer, which is available anywhere and anytime. A notification app
minimizes risks and the information provided allows overload operation, OPEX
reduction and enhanced transformer lifetime planning.

The Siemens Energy digital twin is the first of its kind. Further digital twins will
follow in the near future, complementing the dynamic condition assessment of
a transformer, for example assessing transformer condition when events leading
to failures. Exploiting the overall power of digital twins from different sources will
complete the transformer operation in future, and will provide a permanent, real-
time and independent assessment of asset condition. The holistic twin will be the
all-embracing digital re-build of an asset driving the asset reliability and therefore
the decarbonization to a new level.

Investing in digitalized equipment is an essential step towards transparent, flexible

and reliable grid operation. Better be born connected!
50 CONDITION-BASED
MONITORING

Since the wind and solar facilities were

likely designed with a 20-year life in mind,
the average age of the installed base is
now well into the mid-life span of the
electrical assets, which begs the question
of what to do now. Owners and operators
are faced with options of facility upgrades,
replacement all together or abandonment.

Deploying Wind and Solar energy

operations have long been

condition-based confined to a 15-20-year

maintenance
design life based on turbine
and panel technologies,

technologies
power purchase agreements
(PPA) structures and tax

to extend the life incentives. In many cases

the decisions to repower or

of renewable dismantle renewable power

operations comes down
energy assets to the economics of long-
term maintenance costs and
Photo: Shutterstock

by Justin Melroy equipment failure risks.

By implementing condition-
Transformer Technology February 2022 51

Issue 18

Justin Melroy is a Strategic Account Manager

for Dynamic Ratings focusing on the renew-
able and industrial markets. Since joining
Dynamic Ratings in June of 2021 just has fo-
cused on bringing asset monitoring solutions
to the renewable energy market. Prior to
Dynamic Ratings, Justin held a number of
roles at Eaton Corporation over 8 years cover-
ing utility, industrial, and renewable markets.
Justin has a bachelor's degree in Mechanical
Engineering from Marquette University.

based maintenance The amount of renewable assets In 2008 there was just 0.34 GW of
connected to the grid has exploded U.S. solar. However, as the cost of
technologies into renewable over the last decade, nearly solar has decreased and appetite
generation, energy providers quadrupling since 2011. This has for renewables has increased, the
made the renewable energy sector amount of solar in the U.S. today is
can offset risk, extend the lucrative for investors as well as estimated at 97.2 GW.
life of assets, and reduce promising for climate advocates.
The onset of renewable generation Since the wind and solar facility was
the cost of repowering a can be traced back to the 1970s likely designed with a 20-year life in
facility. This article aims when wind energy began taking off mind, the average age of the installed
as a response to the oil shortages in base is now well into the mid-life span
to shift the status quo of the U.S. After a decade of research of the electrical assets. This begs to
operations and maintenance and development, California saw a question of what to do now; owners
great increase of wind turbines being and operators are faced with options
providers, system designers, installed. Then throughout the 1990s of facility upgrades, replacement all
and energy users towards and 2000s, further developments together or abandonment.
were inspired by government tax
a culture of maximizing the and investment incentives. Even with the rapid expansion in
lifespan of electrical assets renewable energy over the past decade,
Solar power was slower to adopt, “Renewables need to grow faster than
to extend the life of as technology limited utility scale our forecasts to close the gap with a
a renewable operation. projects until the mid-2000s. pathway to net zero by 2050 […]
52 CONDITION-BASED
MONITORING

For solar PV and wind, average to run to failure and substation

annual additions would need to be equipment is monitored on cyclical
almost double what we see in our basis only. As O&M budgets have Online monitoring
main case forecast over the next been trimmed over time, the quality allows operators
five years,” according to a recent of the maintenance may have
IEA study [1]. Owners and operators diminished. to deploy
may be able to close the gap by condition-based
extending the life of current generation Best practices for O&M indicate that
facilities and keeping capacity online investments in proactive maintenance maintenance and
beyond original design life. To do are key to the O&M success. direct maintenance
so, this would require best in class Continuous monitoring systems are
maintenance practices. an efficient means of collecting the resources to known
necessary data to tackle proactive as issues, rather
well as predictive maintenance goals
and keep the power plant running as than injecting
By implementing efficiently as possible. potential problems
condition-based by performing
maintenance unnecessary work.
technologies into Best practices
renewable generation, for O&M indicate
energy providers can that investments In solar applications, the cost of
offset risk, extend in proactive vegetation maintenance and keeping
the panels clean can account for
the life of assets, and maintenance are key as much as one third of the solar
reduce the cost of to the O&M success. O&M costs. It is common that wind
facilities require more maintenance
repowering a facility. and repair activities, whereas the
maintenance requirements for solar
Turbine blade and gearbox tend to lean more towards site
maintenance are some of the higher maintenance. This results in the
The Federal Energy Management maintenance costs associated with generality that solar O&M costs are
Program (FEMP) suggests the a wind facility, leaving the electrical less than wind when viewed on a
following maintenance approaches system to often get overlooked or per kWh basis. However, electrical
for renewable energy facilities [2]: lightly reviewed. However, online maintenance costs are relatively
monitoring of substation transformers, similar and provide equal benefit to
“Modern, effective O&M programs rely turbine step up units, and switchgear extending the life of the equipment.
on four basic approaches: protecting the substation transformer
should be considered since the cost of
1. Reactive/corrective (includes run- the system will be absorbed by lower
to-failure) O&M: Fix/replace when maintenance costs over time.
broken
2. Preventive O&M: Time-based Online monitoring systems not only
actions provide critical data for assessing
3. Predictive O&M: Fix it before it the long-term health of the electrical
breaks equipment, but they also provide a
4. Reliability-centered O&M: A significant reduction in down time
strategic combination of the and lower maintenance costs. Online
previous three approaches” monitoring allows operators to deploy
condition-based maintenance and
For well supported facilities, direct maintenance resources to
Photo: Shutterstock, Dynamic Ratings

operations and maintenance (O&M) known issues, rather than injecting

practices may have included routine potential problems by performing
oil samples and dissolved gas unnecessary work. Online monitoring
analysis, visual inspections and other also reduces unplanned outages and
offline testing of electrical equipment. maintenance durations, keeping the
However, for most of the installed power and revenue flowing in the right
base, the transformers are allowed direction.
Transformer Technology February 2022 53

Issue 18

Renewable applications are still the

new kid on the block when it comes
to the electrical world. In a system
that is designed for stepping down
power from transmission voltages to
distribution levels, a whole host of data
is available to determine the useful life
calculations for utility transformers.
Absent of rich data sets, it becomes
important to begin gathering this
data early in the life of the renewable
asset. Asset owners increasingly rely
on independent service providers, there is lower logistic costs since substation breakers and transformers
OEM provided, or self-performing parts are not being expedited. are minor compared to the benefits of
maintenance work. However, with Production losses can be mitigated the system and the peace of mind in
limited experience in field operations, by performing work when generation knowing the health of the equipment.
the cost of maintenance contracts has is at low points and overtime costs
increased significantly over the years. can be avoided.
As a result, investors are increasingly
looking for wind and solar farms that In other industries, the business When compared
have implemented computerized
maintenance management systems
case for online monitoring can be to a total loss
made based on the impact of an
and asset management systems. Yet, unexpected loss of power impacting of a substation,
there is still resistance to implement
digital solutions as asset owners
production and costing substantial monitoring costs for
equipment downtime. Similar
struggle to justify the up-front capital value propositions can be made for substation breakers
costs. renewable assets. and transformers are
This resistance can be eased by Failure to protect the substation minor compared to
considering the loss of production
and increased maintenance
transformer from partial discharge the benefits of the
and bushing failures may result
costs associated with traditional in catastrophic failures that could system and the peace
maintenance methods. By allowing
an electrical asset to run to failure,
otherwise have been prevented or of mind in knowing
mitigated. Since 50% of bushing
the risk of downtime is significantly failures result in fires [3], the entire the health of the
higher than maintenance guided
by an online monitoring system.
substation is put at risk. When equipment.
compared to a total loss of a
When planned outages are taken substation, monitoring costs for
54 CONDITION-BASED
MONITORING

Transformer loading conditions the required changes [4]. However, Further justification of continuous
leading to premature failures in it is still recommended to closely monitoring systems can be found
wind turbine installations are a monitor transformer performance. by reviewing the data collected
significant concern for operators. Recommendations for transformers by transformer and switchgear
Transformers are typically designed include temperature, pressure, liquid monitoring systems. With capabilities
for constant load conditions, but level and routine DGA sampling of to understand operating conditions
due to the way that wind turbines the oil. When considering the remote over the life of the asset, owners can
are operated, the load conditions location of these sites, it makes make better decisions on whether to
vary significantly, leading to cyclic sense to transition to digital means replace the electrical equipment when
loading and harsh operating of collecting the monitoring data turbine or panel equipment is due for
conditions. These conditions often and implementing online monitoring upgrade. Therefore, reducing the cost
lead to premature failure making solutions. to repower a facility or extend the life
maintenance scheduling difficult. of an existing plant without adding
Continuous monitoring of these unmanaged risk.
assets provides maintenance crews
critical information on the health of
When considering the In conclusion, condition-based
the transformer, and can assist with remote location of maintenance powered by continuous
the maintenance schedules, inventory monitoring systems will play a
planning, and operational consistency
these sites, it makes substantial role in allowing renewable
as transformers and switchgear are sense to transition power operators to maximize the
able to be removed from service lifespan of the electrical assets on
prior to failure reducing the likelihood
to digital means the system. Implementing such
of damage to other equipment and of collecting the systems is a cost effective and
cutting lost production time. proven solution to reduce O&M costs,
As transformer designs have been
monitoring data and extend asset life, improve planning
improved over time to account for implementing online cycles, and keep renewable facilities
some of the issues faced with early online longer. All these things will shift
generation designs, new standards
monitoring solutions. the culture of renewable operations
have been implemented to address and maintenance practices towards
longevity and sustainability which
is needed to address the gap in
renewable generation demand and
production capacity.

References
[1] Renewables 2021, Analysis and
forecast to 2026, International
Energy Agency
[2] Operations and Maintenance
Challenges and Solutions,
Federal Energy Management
Program (FEMP)
[3] Transformer Bushing
Reliability, CIGRE A2 Technical
Brochure
[4] Philip J Hopkinson, “Defining
& Specifying Transformers for
Wind and Solar Applications,”
IEEE PES
Photo: Shutterstock, Dynamic Ratings
Transformer Technology February 2022 55

Issue 18

The benefits and implementation of

continuous monitoring systems will shift
the culture of renewable operations and
maintenance practices towards longevity
and sustainability which is needed to
address the gap in renewable generation
demand and production capacity.
56 ADVERTORIAL

PTTX LATE-MODEL BOOSTING

ECO-FRIENDLY LOW-CARBON
TRANSFORMER CORE DEVELOPMENT
PTTX promotes the manufacture of late-model
eco-friendly transformer cores with professional
technical support, novel production technology,
and supporting full-process services, so as to
reduce transformer no-load losses, save energy
and reduce emissions. PTTX uses practical actions
to boost ‘carbon peaks and carbon neutrality’,
aimed to promote the green development in the
Photo: PPTX

power industry.
Transformer Technology February 2022 57

Issue 18

China strives to achieve carbon peaks by 2030 (once carbon peaks are reached,
carbon dioxide emissions no longer increase, but start to decline) and achieve
carbon neutrality by 2060 (carbon neutrality is reached when enterprises,
groups and individuals offset the carbon dioxide emissions they generate and
achieve zero carbon dioxide emission by afforestation, energy saving, emission
reduction, etc.). As a leading enterprise in the transformer core industry, PTTX
takes the lead in low-carbon emission reduction green manufacturing, taking
social responsibility, and making contributions to the power industry.

On June 1, 2021 China officially implemented the new version of the “Minimum
allowable values of energy efficiency and the energy efficiency grades for power
transformers” (GB 20052-2020) standard. In the new standard, the standard
loss index for all types of transformers will be reduced by about 10-45%
compared to the old standard. This is better than the requirements set by the
European Union (which implemented the new standard on July 1, 2021) and the
United States.
58 ADVERTORIAL

The implementation of the new energy efficiency standard further promotes the
transformation of the entire power transformer network. If the new Grade-1 energy
efficiency transformers, which are made from high grade oriented electrical steel,
can cover China's current distribution network, it is estimated that this can save
87 billion kWh of electricity per year, equivalent to 86.7 million tons of carbon
dioxide emissions.

Facing such astonishing data, PTTX firmly believes that we should make our due
contribution at the times when the power industry needs it.

High performance grain-oriented electrical steel is the most suitable material

for the manufacture of the Late-model Eco-friendly Transformer under the new
energy efficiency standard. The production technology of high grade grain-
oriented electrical steel is complex, and PTTX actively carries out research and
development of this steel, material innovation and technology upgrade. Through
Photo: PPTX

the efforts of our R&D team, the quality of PTTX grain-oriented electrical steel is
steadily improved.
Transformer Technology February 2022 59

Issue 18

PTTX's research is not only based on the upgrade of grain oriented electrical steel
materials. Approaches to applying high-performance grain oriented electrical
steel in the design of the Late-model Eco-friendly Transformer Core is an added
value that PTTX R&D team has brought to clients.

The higher the performance of grain-oriented electrical steel, the higher the
calculation requirements for transformer core design. The higher the grade of
grain-oriented electrical steel, the thinner its thickness, the higher the level of
processing technology requirements.

In the case of 0.20 mm and 0.23 mm thick grain-oriented electrical steel, which is
in highest demand, many transformer companies have come under the pressure
of design and processing difficulties.

PTTX provides clients with Late-model Eco-friendly Transformer Core design

solutions to solve design problems.

Through the use of high quality PTTX grain oriented electrical steel, with design
and processing technology innovation and the use of intelligent manufacturing
technology, we offer clients an ability to customize Late-model Eco-friendly
Transformer Core.

Transformer cores are different from general mechanical manufacturing products

which can be shipped to clients in simple packaging. If the transformer core is not
properly protected, this will have a great impact on its performance. For example,
in severe weather, we should pay more attention to strengthening external anti-
corrosion. During the shipment, appearance damage under the influence of stress
should be avoided. Attention should also be paid to avoiding attachment of metal
dust and other foreign bodies, etc.

At PTTX we investigate best logistics solutions for the transformer core and
we develop exclusive transformer core packaging protection and logistics
operations and services to ensure that the product arrives intact to the client.

PTTX is not only a transformer core manufacturer, but also a developer of green
manufacturing system solutions. For the transformer core manufacturing
requirements, we have asked ourselves many questions and devised many
solutions accordingly, which seem to have exceeded the necessary core
requirements. This speaks of our dedication to every detail of transformer core
manufacturing, and the focus on each of our client’s expectations of our quality.

PTTX uses practical actions to boost ‘carbon peaks and carbon neutrality’,
aimed to promote the green development in the power industry.

Contact us:

Wuxi Putian Iron Core Co., Ltd.

E-mail: pttx@pttx.com
Web: en.pttx.com
Tel: +86 510 83798338
Fax: +86 510 83798338
Address: No.19 Jingxiang Rd,
Xishan District, Wuxi, China

PTTX Global Offices:

Headquarters: Wuxi, China
European Office: Frankfurt, Germany
Middle East Office: Dubai, UAE
60 RELIABILITY

Reliability:
A Compound Effect
by Traci N. Hopkins

What is your definition of reliability?

If you ask this question 100 different people, you will receive nearly 100 different answers.
However, the underlying theme will remain the same: Reliability is the expectation
that the asset in question will perform as designed and as expected without fail.
However, at some point in the life of that asset, there will be a “blip” in its operation that will lead to two very definite outcomes.

The first is that this item will now be viewed as “unreliable”.

The second is permanent failure.
 Transformer Technology February 2022 61

Issue 18

What is the definition of reliability and how do you

maintain an asset’s reliability? Your answer should
funnel down to three distinct areas: small changes,
consistency, and time.
Now that we’ve defined Reliability, Small Changes
let me ask the question: How do you
maintain your asset’s reliability? In our current culture we want results,
Traci Hopkins started her journey in electric Similar to the first question, if you and we want them now! We need
power reliability in June 2012 with SDMyers, ask 100 people, you will receive a to be able to produce evidence that
LLC in the Training & Education department. multitude of strategies and actions our efforts to maintain an asset will
Shortly after, she transitioned into the role of to ensure an asset’s reliable status. produce a significant Return on our
Diagnostic Analytic Coordinator for the inter- However, the key to maintaining Investment. For many, this means big
national market while continuing to support reliability can be written as a simple changes = big impact. However, if we
training & education through international equation: look at the effects of small changes
events. In 2017 she made her way back to T&E to not only maintenance activities,
as the Sr. Training & Education advisor and Small Changes + Consistency + but budgets, time and ability, and the
Adjunct Instructor. Recently, she has joined Time = Reliability willingness of staff to implement said
the Electric Power Reliability Alliance (EPRA) changes, we can observe that small
team as Membership Recruitment Coordina- This “Reliability Equation” is nothing modifications are a more effective
tor. Traci has received the CRL, MTMP, MTRP more than the “Compound Effect”. and efficient means to achieve higher
and DPS Training certifications. Traci is also Let us break down this equation, reliability and maximize the life of our
evaluate each variable and observe assets. Small changes also provide
Photo: Shutterstock

a member of IEEE PES, the Association of

Asset Management Professionals, and WIRAM how they apply to electric power the flexibility to course-correct without
(Women in Reliability and Asset Management) reliability, specifically transformer any significant negative impact to the
organizations. reliability. factors mentioned above.
62 RELIABILITY

IEEE Std C57.91-1995 IEEE GUIDE FOR LOADING

Table 1 - Aging accelaration factor

Temperature oC Age Factor Temperature oC Age Factor Temperature oC Age Factor

<37 0.0000 65 0.0054 94 0.1813

38 0.0001 66 0.0062 95 0.2026

38 0.0001 67 0.0071 96 0.2263

39 0.0001 68 0.0080 97 0.2526

40 0.0002 69 0.0091 98 0.2817

41 0.0002 70 0.0104 99 0.3141

42 0.0002 71 0.0118 100 0.3499

43 0.0002 72 0.0134 101 0.3897

44 0.0003 73 0.0152 102 0.4337

45 0.0003 74 0.0172 103 0.4823

46 0.0004 75 0.0195 104 0.5362

47 0.0004 76 0.0220 105 0.5957

48 0.0005 77 0.0249 106 0.6614

49 0.0006 78 0.0281 107 0.7340

50 0.0007 79 0.0318 108 0.8142

51 0.0008 80 0.0358 109 0.9026

52 0.0009 81 0.0404 110 1.0000

53 0.0011 82 0.0455 111 1.1074

54 0.0012 83 0.0513 112 1.2256

55 0.0014 84 0.0577 113 1.3558

56 0.0016 85 0.0649 114 1.4990

57 0.0019 86 0.0729 115 1.6565

58 0.0021 87 0.0819 116 1.8296

59 0.0024 88 0.0919 117 2.0197

60 0.0028 89 0.1031 118 2.2285

61 0.0032 90 0.1156 119 2.4576

62 0.0037 91 0.1295 120 2.7089

63 0.0042 92 0.1449 121 2.9845

64 0.0048 93 0.1622 122 3.2865

IEEE C.57.106.1995, Table 1 – Aging acceleration factor (Source: [1])

Transformer Technology January 2022 63

Issue 18

In the case of transformers, it’s

important to consider the asset’s
criticality, health status, and the
impact and consequences of failure
to the organization. In today’s power
systems, the average age for an in-
service power transformer is 38
years. Many electric power reliability
professionals find themselves in
situations where they must manage
multiple units that include not only
“average-aged transformers”, but
new units and ones that far exceed
the average transformer age.
This assortment of transformers
possesses great challenges,
especially when the age gap of these
assets can span ten, fifteen, even
twenty years or more. In situations
like these, it’s imperative to realize
that the robust overbuilt transformer The use of online gas monitors for in the transformer management
of yesteryear and the new, sleek, new and in-service units, customized program through smaller, more
more streamlined transformer testing programs for the liquid manageable steps, providing an
of today each require a different insulation, the use of appropriate opportunity to course-correct as
maintenance philosophy. electrical test methods and testing needed without significant impact
intervals during the transformer’s to the asset, the maintenance
Knowledge and lifecycle, and the adaptation and program, or operations.
inclusion of newer evaluation
understanding of the
test data joined with
technologies such as Ultrasound
and Vibration Analysis are all part
Think about this
experience affords the of the necessary tasks required to interesting fact:
reliability professional
assess a transformer’s health and
reliability. Yet one must not discount
by performing one
an opportunity to the importance of active participation service, for example:
implement big changes
in organizations dedicated to the
advancement of electric power
re-inhibiting, mois-
in the transformer reliability, and, most importantly ture reduction, oil
management program
the establishment of a consistent
training and education program for
reclaiming, etc. on
through smaller, more everyone involved in the care of a transformer, you
manageable steps.
these assets.
can gain an average
Knowledge and understanding of of seven years of
The mediocre maintenance strategy
on the over-built unit has sufficed
the test data joined with experience
affords the reliability professional an
in-service life on
up until this point; mostly, due to an opportunity to implement big changes that unit.
overabundance of caution on the
manufacturer’s part with an added
cushion of solid and liquid insulation
beyond the design requirements. This
minimalist strategy that has worked
for decades is now antiquated,
inefficient and harmful to a reliability-
focused strategy, as new units
require a more conscientious and
active approach in their maintenance
and management strategies. Small
changes in the chemical, mechanical,
and electrical evaluations of
these assets, on all sides of the
age spectrum, can be extremely
impactful.
64 RELIABILITY

Consistency Time

Once we’ve developed a plan and The ability to avoid turning new habits The third and equally as important
begun to implement those changes, into complacent tasks, and the act addend in this equation is time.
it’s imperative to remember the next of continuously seeking knowledge You have to be willing to “be in it for
part of our equation: Consistency is what sets reliability professionals, the long haul”. Theoretically, power
– Trust the Process. Change thought leaders and subject-matter transformers have a life expectancy
occurs when you are motivated and experts apart from the crowd. It’s of more than 400 years. I have had
disciplined. Discipline is what is left this ability to keep moving forward, the pleasure of being witness to
after motivation leaves the room. routinely evaluate the effects of these the celebration of several units that
In the case of power transformers, small, incremental changes and a have exceeded 100 years of service
we need to have the discipline and consistent and faithful dedication to and are still going strong. Time is
wherewithal to resist the temptation the process that begins the transition our most precious resource and one
of falling back into old maintenance from simply maintaining the asset to that we cannot regain. However, in
habits. Understanding the “Why” a true reliability mindset. the world of power transformers I
helps us to remain uniform with all like to challenge that last statement.
our tasks and activities. Think about this interesting fact: by
It’s the ability to keep performing one service, for example:
Transformer maintenance and
management is all about the data.
moving forward, re-inhibiting, moisture reduction, oil
reclaiming, etc. on a transformer, you
The consistency of transformer routinely evaluate the can gain an average of seven years of
testing: chemical and electrical, visual
inspections, infrared thermography,
effects of the small, in-service life on that unit.

and other test data provides us with incremental changes Consider these interesting facts
a baseline of information about the
health of the transformer. Over time,
and a consistent and about the transformer’s solid
insulation system and temperature:
the data we accumulate from these faithful dedication we can observe and calculate the
tasks becomes information. We
couple this with knowledge acquired
to the process temperature interval (increase) that
will cut the life of the paper in half;
through training and education efforts that begins the conversely, we can also calculate
and we begin to develop a complete
assessment of the health of the
transition from simply the temperature interval (decrease)
that will double the life of the solid
transformer. This assessment is then maintaining the asset insulation and increase the life of the
used for trending analysis, industry
comparison, predictive maintenance,
to a true reliability transformer. Finally, did you know
every time you double the moisture
and planning for end of life. mindset. content in a transformer you are

Photo: Shutterstock
Transformer Technology January 2022 65

Issue 17

effectively halving the reliable life of three months later? It is said “the
that unit? Imagine how much time best things take time”. Well, so does
could be gained on the life of an Reliability. I’m sure we all remember
in-service unit if we started off with the lesson from story of the Tortoise
a reliability mindset from the very and the Hare, slow and steady wins
beginning, the design phase. the race.

When it comes to time, it’s important

to remember to be confident in your
Imagine how much
decisions, knowledge, and abilities. time could be gained
There are many documents to help
you achieve success in your journey,
on the life of an
covering everything from the what in-service unit if we
to the how and even the why. Think
about it this way, you wouldn’t throw
started off with a
in the towel after one workout at the reliability mindset from
gym, NO! So why do we regularly
implement new programs and
the very beginning,
processes only to abandon them the design phase.
The compounding effects of these
three factors when done carefully
and with intention are what set the
reliability professional apart from the
average maintenance worker.
A dedication to the art of interpreting
data, converting it to information,
translating that information into
knowledge and eventually into
wisdom is a path which all “reliability
focused” organizations must take.
Fortunately, in today’s world of power
transformers, we have access to the
resources, training, subject matter
experts, colleagues, associations, and
organizations at our fingertips. With
a click of a mouse, the stroke of a
keyboard, or a phone call we can easily
access communities of electric power
professionals and find many potential
solutions to our inquiries.

The ability to implement small changes

on a consistent basis over a period of
time will unify the organization, achieve
the intended goals and extend the
reliable life of one of the most valuable
assets in any electric power system,
the transformer. Now, I urge you to go
back to the beginning and ask yourself
the same two questions again, what
is the definition of reliability and how
do you maintain an asset’s reliability?
Your answer should funnel down to
three distinct areas: small changes,
consistency, and time. These three
References addends, when given the opportunity,
[1] IEEE C57.91-1995 – IEEE will equal an increase in the reliability
Guide for Loading Mineral-Oil- of our assets and personnel, and effect
Immersed Transformers positive change in our organization’s
reliability culture.
A BETTER ENERGY FUTURE IS
A FUTURE OF COLLABORATION
66

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 Transformer Technology WOMEN February 2022 67

Issue 18 OF NOTE

Aleezeh Shahid

Technology
a n a ly st at Power am
Aleezeh is a
se n io r research te
le a d s th e power grid d s e rvices
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search, wher urrently lea
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automation
and a m e including w s Aleezeh Shahid
lications to
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Photo: Aleezeh Shahid, rawpixel.com

her current
68 TRANSFORMER
MONITORING

Transformer Condition Assessment:

Moving from Data to Actions

by Emilio Morales
and Thomas Linn

Correlative
analyses and
data analytics
enable users
to evaluate
the probability
of failure by
using different
parameters,
which can be
supportive or
contradictive
to each other
when used
individually in
Photo: Qualitrol

failure mode
assessment.
Transformer Technology February 2022 69

Issue 18

Emilio Morales attended Nuevo Leon State

University in Mexico, receiving his bachelor’s
degree in Electromechanical Engineering
in 1980. He has over 30 years of experience
in power transformer design which includes
transformers up to 500 MVA and 500 kV, fur-
nace and rectifier transformers and reactors.
He is member of the IEEE/PES Transformer
Committee, IEC and CIGRE. He previously
worked with GE-Prolec, Ohio Transformer,
Sunbelt Transformer and Efacec. He joined
Qualitrol in June 2012 as a Technical Appli-
cation Specialist in transformer applications.
His focus is to support solutions in compre-
hensive monitoring for transformer applica-
tions.

Thomas Linn graduated from the Technical

University of Dresden with a degree in Electri-
cal Engineering, specialized in High Voltage
Techniques. In 1998 he joined ABB in Switzer-
land where he was responsible for high volt-
age onsite testing for GIS and cables, on-site
PD measurements and PD monitoring of Gas
Insulated Switchgear. Afterwards he worked
for 10 years with high voltage transformer
bushings at Micafil. During that time, he was
responsible for high voltage test laboratories
for routine and type testing and later for the
whole manufacturing process. Latterly, he
was senior project manager for strategic pro-
jects, project portfolio manager and senior
technical expert for high voltage techniques
and equipment. Today he is working as a
Technical Application Specialist for Qualitrol.
70 TRANSFORMER
MONITORING

Introduction independent parameters or basic set of actions for rectification needs

trending. Users struggled accessing to be determined.
The changes in global energy politics, the true overall condition of an asset.
motivated by multiple reasons, have Typical statements were and still Analytic Models – Creating
driven the electrical power industry are “I got an alarm, but what does Information Instead of Data
not only to devising more efficient it mean to my asset? What are the
solutions, but also to an increased actions to mitigate an immediate The knowledge of failure statistics,
use of renewable energy resources. thread?”. In a lot of cases confusion problems and failures of a
Energy production today has become prevailed over clear decisions. “False particular transformer fleet, and an
more decentralized with renewable alarms” lead to a lack of trust in the understanding of failure mechanisms
energy being generated regionally, installed monitoring solutions. combined with criticality analysis
away from the main consumers. are essential to choosing the right
The decentralized power generation parameter for an assessment and
meant that electrical networks Figure 1. Scattered data approach building up analytic models. Today
needed to be reconfigured. The elec- asset assessment will be mostly
trical energy today needs to be trans- understood as a tool to prevent
mitted over longer distances from failures and enable Condition
generating stations to the con- Based Maintenance (CBM). But
sumers. Reverse electrical online condition assessment
energy flow can happen could also be a powerful
and it needs to be con- tool for asset operation.
trolled, placing an ad- The prediction of
ditional burden on a certain load
electrical network condition and the
components. risk status of
electrical assets
With these high- can be used
er complexities for dynamic
and the require- loading. As the
ment to increase pressure on the
the speed and owners regarding
reliability of as- financial
set health asses- efficiency
sments and main- increases,
tenance decisions, dynamic loading
the collection of becomes more and
condition data and more important.
the translation into ac-
tionable data becomes Presenting “only” the
more essential. This all data and trending can be
happens under the thread of misleading, leading to poor
climate change and is therewith maintenance and/or operational
connected to more sever climate decisions and unnecessary
conditions which have been proven interventions, which usually have
to test the resilience of the electrical the potential to introduce new risks.
energy network even further. Figure 1 illustrates this scattered
To efficiently assess the condition data approach and how it often fails.
Transformers as a key asset of of a transformer and to convert the In many cases users find it difficult
electrical networks receive special data into actionable information, the to analyze scattered data. Data
attention regarding condition and failure mechanism, its associated are analyzed separately ignoring
risk assessment based on availability monitoring parameter(s) and the the possible relationship to other
requirements. Offline condition dedicated analytic model must be parameters or even legacy data.
assessment methods are established known and must be considered in
and used for decades with success their entirety. Correlative analyses A practical example is partial
but require an outage to be able to and data analytics are gaining more discharge (PD) measured on a
perform them. Nevertheless, they give importance as they enable users to transformer bushing tap. Considering
a momentary screenshot of the asset evaluate the probability of failure by only the detected PD could lead to
at the time of the measurements, so using different parameters, which the decision to further investigate and
the development of incipient faults can be supportive or contradictive to perhaps open the transformer trying
can be missed between outages. each other in their individual failure to find the failure. Since the source
Introducing online monitoring in the mode assessment. Once a potential of PD can be the overhead lines or
past was most often limited to some incipient fault has been identified, a the bushing surface, it would be
Transformer Technology February 2022 71

Issue 18

Data Layer sophisticated artificial neuronal

Data Layer (e.g. amplitude, phase correlation, time of arrival, etc.)
network approaches, fuzzy logic,
Information Layer
First Abstraction Level (e.g. PD pattern, etc.) etc.) and further verified with the help
Second Abstraction Level (e.g. PD pattern recognition, etc.) of other related data (e.g. PD and
Parameter Abstraction Level (e.g. clear text information with recommended actions, etc.)
Dissolved Gas Analyses (DGA) for
Abstraction transformers).

The abstraction level can be arbitrarily

Figure 2. Data abstraction level concept continued. Figure 3 shows the
abstraction level at the network layer
(top left picture) and the substation
necessary to consider the possibility important to extract the relevant layer (top middle) for the substation
that the discharge originates information. Using the PD example under concern.
from outside of the transformer. again, this means that PD impulses
Appearance and disappearance of must be related to their position in To assess a certain alarm or warning
PD for longer periods, mostly related the phase of the line voltage, which condition, different parameters should
to climatic conditions, is a clear sign then allows to combine the single be correlated to each other, including
of external discharges (e.g. surface impulses to different pattern types online and offline data, as well as data
discharges on the surface of the (PRPD pattern – phase resolved from different sources, e.g. SCADA
bushings or corona discharges on partial discharge pattern, 3D pattern, systems, periodical visual checks, load
the overhead lines). At first sight this point of wave, etc.). Adding the data, etc. This would allow correlation
example might seem very basic, but time of occurrence will also provide of complementary parameters.
it is one of most common problems additional information for PD Automated correlation of data can
in terms of PD monitoring on the analysis. For example, comparing be done for online data. Available
bushing tap. It would need a lot additionally the time of arrival offline data has often been reviewed
more parameters than just the PD and/or amplitudes of the same PD manually but seldom automatically
from the measuring tap to be able impulses at different sensors will via an interface uploaded to an
to distinguish between internal and give further useful information about analytical tool or platform which has
external origins of PD. PD origin. Figure 2 shows how the the analytic ability to marry online and
collected data can be analyzed offline data and convert these into
Besides reliable capturing of the data through different abstraction actionable information for operators
for the chosen parameters, it is also levels (analyzed by simple logic or and maintenance crews.

Figure 3. Information abstraction from network to substation and down to parameter level view

Country wide view: Showing all substations Station level view: Line diagram showing assets Asset level view

Parameter level view: Showing all displays, data trends and other analysis for each parameter
72 TRANSFORMER
MONITORING

Failure Statistics, Asset Loose parts, sharp edges, fans and pumps can support an
Components and Failure delamination of bulk insulation, early detection of malfunctions. In
Mechanisms conductive particles in oil, bad a simplified approach, the top and
contacts and gas bubbles in oil all bottom oil temperature correlation
Failure Statistics have the potential to weaken the with the actual load condition can
liquid and solid insulation system and give a rough indication of a severe
The latest transformer reliability to create partial discharges (PD) and condition as well.
study, published in CIGRE Brochure arcing. Strong discharges as a result
642 [2], shows that windings are the of these defects can decompose the Transformer bushings
major cause of transformer failures oil/paper insulation and/or erode the
with 45%, followed by tap changers conductive material. Bushings are components that
with 26%, bushings with 17% and guarantee the transport of the
lead exits with 7%. All other major Further failure can be caused by electrical energy (voltage and current)
transformer components play a local overheating and burnings due into and out of the transformer from
minor role (see Figure 4). The overall to bad contacts, by circulating core and to the electrical network. For
transformer failure rate according ground current or bad or missing higher voltages mainly above 36
to [2] is 0.44%, while transformers connections from core to ground and kV (for generator step up units and
for extra high voltage (EHV) and the from magnetic or electric screens. also high current bushings of 24 kV
lower end of high voltage are showing and 36 kV) capacitor type bushings
a failure rate of around 1%. Transformer LTC are being used. The major causes
of failure in bushings are moisture
Asset Components Load tap changers (LTCs) are the only and partial breakdowns (breakdown
part in a transformer that actively between two or more conductive
All transformer incipient faults will mechanically operate. Wear and tear layers of the bushing insulation).
somehow result in the creation of of the mechanical parts and contacts Partial breakdowns are mainly
detectable signs of their presence. can influence the ease of movements. caused by transient overvoltages
These signs could be chemical, Parameters like liquid temperature or pre-deterioration due to partial
electrical, optical, or acoustic in difference between the main tank and discharges. Leakages on porcelain
nature, but often they will be a LTC compartment, DGA, motor drive sealings especially in case of oil
combination of these. Further, torque, motor drive current index, impregnated paper bushings (OIP)
a selection of possible fault operating time, contact wear or vibro- are responsible for moisture ingress.
mechanisms related to certain acoustic signature can be a good Meaningful indicators to look for
components will be described as indicator to detect any abnormalities. here are the Power Factor and the
simple examples to illustrate the Capacitance Considering catastrophic
potential of certain parameters to be Transformer Cooling System failures, according to [3], bushings are
used as indicators of incipient faults. in 70% of the cases the cause, there
The main concern regarding the are other components leading the
Transformer Main Tank cooling system of a transformer transformer to fail but with less risk
is to ensure the oil and air flow of a catastrophic failure.
The main concern regarding the through the coolers/radiators is
transformer main tank is the always guarantied. This can be done Analytics and Correlative
dielectric integrity of the liquid, bulk by natural convection for smaller Analyses
and paper insulation, as well as transformers or, in case of larger
their accelerated aging by local and power transformers, by a forced Analytics is concerned with finding
general overheating and moisture. cooling system. In oil forced cooling meaningful patterns based on input
This is tightly connected with the risk system pumps are used to circulate data, existing static models (like
of bubble creation at high moisture the oil through the radiators/coolers formular/calculations) to dynamic
and dissolved gas content combined and fans are meant to circulate the models (like machine learning data
with high temperatures. Moisture air through the radiator fins and analytics) and converting it to a
and overheating will accelerate cooler rips to take the heat away. useful output. Correlative analyses
the aging of the cellulose. This will More complex systems are using can be part of the analytics or
create decomposition products water to cool the oil. In that case in a simpler way a standalone
of the cellulose, among them pumps are also circulating the water. technique, combining information
water (moisture), which in turn will If the cooling system is disturbed by based on different parameters and
accelerate its aging even more. Over malfunctions of fans or pumps, the from different sources. Both are
time, the insulating paper will lose its oil and thus the transformer cannot using abstraction algorithms. The
insulating and mechanical properties be cooled down in an appropriate bubbling temperature model, which
until it cannot withstand any electrical way, which can lead to overheating calculates the temperature for bubble
or mechanical stress, increasing the and transformer failure. Changes in evolution based on existing static
probability of transformer failure the relationship of inlet and outlet model (formular) is an example of
in the event of voltage transient or temperatures of the cooling banks a simple static analytic model. It is
through fault. or changes of motor load currents, used to determine the temperature
Transformer Technology February 2022 73

Issue 18

Table 1. Transformer failure statistic [2]

HIGHEST SYSTEM VOLTAGE [kV]

FAILURES &
69 ≤ kV < 100 100 ≤ kV < 200 200 kV< 300 300 kV< 500 500 ≤ kV < 700 <= 700 kV All
POPULATION

FAILURES 144 300 229 241 36 14 964

TRANSFORMER
15,420 67,996 41,656 32,045 6,611 3,731 167,459
- YEARS

FAILURE
0.93% 0.44% 0.34% 0.75% 0.54% 0.37% 0.57%
RATE/YEAR

Figure 5. PD pattern recognition on PD data abstraction process

Figure 4. Transformer major failure statistic [2]

0.30%
Winding
0.30%
WindingLead Exit
Lead ExitInsulation
23.20% Insulation
23.20% Electrical screen
Electrical screen
1.00%1.00% Bushing Bushing
47.40%
47.40%
0.50%0.50% Core andCore andcircuit
magnetic magnetic circuit
3.80%
3.80%
0.40%0.40% Flux Shunts
Flux Shunts
Tank
14.40% Tank
14.40% Cooling unit
Cooling unit
Tap Changer
6.30%
0.40% 2.40% CT Tap Changer
6.30%
0.40% 2.40% CT

Figure 6. Overview correlative analyses

Single Parameter Data Input

Data Layer Data Layer Data Layer

Information Layer Information Layer Information Layer

Single parameter Parameter 1 Parameter 2 Parameter 3
assessment level Abstraction Abstraction Abstraction

Parameter
correlation level

Asset assessment Support Contradict Complement

level
Transformer Assessment
74 TRANSFORMER
MONITORING

at which the gas bubble generation Practical Example Using analytic

starts. To enable this calculation,
a set of different input parameters In this case a single phase, extra models and
needs to be known, like the hot spot
temperature, moisture in oil, gas
high voltage (EHV) autotransformer correlative analyses
was equipped with a comprehensive
content in oil, pressure at the hot monitoring package including DGA, allows users to
spot, temperature of the oil at the
moisture sensor and the ambient
UHF PD, bushing, and temperature make reliable
monitoring. The transformer had
temperature. A more sophisticated been three months in service and decisions about their
approach is the artificial neural
network-based PD pattern
experienced a catastrophic failure. assets, increasing
DGA and bushing monitor did not
recognition as shown in Figure 5. alarm, but the PD monitor showed the confidence in
Correlative analyses, instead, aim
strong PD activity eight hours before transformer health
the fault occurred. This shows that
more at the “if…then….” approach correlative analyses not only support assessments and
(Figure 6). For example, if the
detected moisture value in the
or contradict each other, but also allowing the use
can complement each other as seen
transformer is higher than usual, this in this case. One method, the UHF of complementary
can be caused by different reasons.
Reviewing the site visit reports
PD, was able to detect the change models.
of condition in real time, while
shows that some oil drops have one of the other two methods, the
been discovered on the sealing of the DGA, was too slow due to the time
transformer. That can be translated needed by the generated gasses
to “If moisture has been detected and to dissolve in the oil [5]. The utility
oil drops (signs of leakage) can be did not have experience with the
discovered, then there is a severe oil UHF PD monitoring and was not
leak which influences the condition of expecting this new transformer to
the transformer”. Similar approaches fail. It decided to observe the PD
can also be taken between PD activity behavior before setting thresholds
and DGA, PD activity and core ground to activate alarms, therefore, the
current, etc. UHF PD monitoring system was not References
connected yet to their Scada System [1] S. Beneyto, J.Vantyghem,
Table 2 shows an example of and the failure was not detected. “Discussion on the
correlative analytic models for failures After this experience, the utility deregulation of electricity
in the magnetic circuit considering applied the history data to stablish markets,” Mines ParisTech,
different parameters and its detection PD thresholds and was able to http://www.energypolicyblog.
time. detect this type of behavior in similar com, [Online] 06 06, 2010.
transformers and avoid catastrophic [Cited: 01 20, 2014]
Five different analytic models shown failures. http://www.energypolicyblog.
in Table 2 are readily available. For com/2010/06/06/discussion-
each of the models different input Conclusion on-the-deregulation-of-
parameters need to be gathered and electricity-markets/
each of the models/parameters has The power industry today demands, [2] CIGRE Brochure 642,
its own detection time. It is useful to besides the conventional transformer Transformer Reliability Survey,
use more than one analytic model for gauges and well established Working Group A2.37, CIGRE,
a certain failure mechanism. In the online DGA applications, a more 2015
above example most probably the comprehensive condition assessment [3] H.-P. Berg, N. Fritze, “Reliability
DGA model, the core ground current approach to implement condition of main transformers,“
model and the PD model would be the based monitoring principles, to make Salzgitter, Germany,
best fit. In that case the parameters transformer operation more efficient Bundesamt für Strahlenschutz,
to measure are dissolved gases, PD and optimized, as well as to be able 2011
and the core ground current. to detect incipient faults in an early [4] 57.91, IEEE WGC, IEEE Guide
stage. for Loading Mineral-Oil-
Similar models are made for different Immersed Transformers and
kind of failure mechanisms in The demand for analytic models, Step-Voltage Regulators, s.l.:
the transformer main tank, LTCs, which allow users to make reliable IEEE, 2011. IEEE C57.91-2011
bushings, cooling systems, GIS, etc. decisions about their assets, is [5] C. Schneider, “Lessons
Regarding the importance of that exponentially increasing. Using Learned from Failed Assets
particular asset and its history a correlative analyses increases the at EHV,” Conference on Online
decision about the types of failure confidence in transformer health Monitoring of Electric Assets
mechanisms needs to be considered assessments and will allow the use (COMET) 2014, Austin TX
for monitoring. of complementary models.
Transformer Technology February 2022 75

Issue 18

Table 2. Magnetic circuit correlative analyses

Failure Measured signals/

Component Analytical model Detection time
mechanisms parameters

Magnetic Core ground Loss of core DGA Model Hydrogen or Hours

Circuit lead ground multi-gas

Unintentional
Magnetic core and Core Ground Core ground Days
shield shield Current Model current
grounds
create
problems and
discharges

Gas Accumulation Gas Real time

Rate Model accumulation

Thermal Model Core hotspot Hours

(Fiber)
Temperature

PD Model PD Real Time

WHAT IS YOUR
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76 PRE-SHOW
FEATURE

2022 IEEE PES

T&D Conference
and Exposition:
Reconnecting Pre-show Interview with Wayne Bishop Jr.
in the Big Easy Vice President of Meetings & Conferences
for IEEE PES

Wayne Bishop
I became the VP of Meetings & Conferences,
a volunteer position for IEEE PES, back in
2019, and I was in it for about a year and
a few months when COVID hit. And boy,
did it hit. We had to quickly pivot all our
meetings. Keep in mind, I oversee all our
meetings worldwide for IEEE PES. We had to
pivot from in person to virtual meetings and
Alan Ross it was a tremendous undertaking. But we
It’s my pleasure to talk to a dear friend, ended up reaching more members that way,
Wayne Bishop, the Vice President of digitally. For example, for our annual Power
Meetings & Conferences for IEEE PES, about Africa conference we doubled the number
the IEEE PES T&D Conference and Expo of countries that attended the event, so we
coming up in April 25th through the 28th actually reached more members. But we
in New Orleans. But before we go there, I can't wait to be back face to face. We just
want to talk about how after you took over miss the camaraderie, not even necessarily
the role as Vice President of Meetings and the meetings themselves, but the coffee
Photo: IEEE PES

Conferences, this thing called COVID hit. breaks, the meetings that occur outside of
How has that impacted what you all have the main meetings and main conferences.
been able to do? So, I just can't wait to get back face to face.
Transformer Technology February 2022 77

Issue 18

Alan Ross Wayne Bishop

Having been to the last five IEEE PES T&D As mentioned, this year's T&D Conference and
Conferences and Expos, the one thing I've Expo will be in New Orleans, and the host is
missed is what happens on the Expo floor. Entergy, a great utility that got behind this with
That’s not a buying floor; people don't go their team. The chair of the Conference and
there to buy. They go to learn. And it is a great Expo is Michelle Bourg. Michelle is Vice President
opportunity for the people that show up of Asset Management at Entergy, and she has
and support the Expo to be able to explain assembled a great team. Heading up the technical
new things. Technology is changing so much program is Chang Wang, another very active IEEE
and rapidly, and you can deliver technical PES member from Entergy. He has put together a
knowledge. But when you discuss technical great program that will consist of a great opening
knowledge, it kind of creates a camaraderie session with four super sessions throughout
that you just have to experience. We get to the week, panels, papers – literally hundreds of
meet with old friends, talk about new things, presentations. And as we mentioned earlier, there
and connect with new people. I know that the are so many changes happ ening right now in the
host of this conference is Entergy, and they utility industry and the power industry: everything
have put on a really good technical program to from integrating DER onto the grid, through
present. Talk a little bit about that. dealing with electrification of the transportation
system, to our assets getting older and what we
need to do with these assets and how we should
be maintaining them with all of the trends that are
happening. Our industry has had more changes
in the last 10 years than the last 100 years. Many
of these changes and how the utilities are dealing
with the changes will be addressed at T&D.

Regarding the Expo floor, I can't help but mention

that we have over 550+ exhibitors covering every
aspect of transmission and distribution, along with
more big trends. We have made a lot of changes to
T&D as well, new changes, new initiatives.

Alan Ross
When we were set to do this in 2020, you had
an innovation platform, and we were going to Wayne Bishop
have a media platform. You had a lot of things We are proud of what we are launching for this
that you were doing, including the “pay for one T&D. We tried to launch it in 2020, but of course,
and get ten” to come from the utility industry, T&D was cancelled. So this year we will launch
to try to get more practitioners. Are those officially our utility bundled pricing package and
initiatives still in place? how that works.
78 PRE-SHOW
FEATURE

Alan Ross Wayne Bishop

It sounds like you're a marketer. I'm part marketing so that's the marketing coming
out. As you said, we really want the practitioners
there. We want the utility engineers to come, and
we want the price to be attractive. We are offering
utilities to send ten people from the utility for only
$1,000. In other words, $100 a person, grand total of
$1,000. When we launched this back at the last T&D
in 2020, we had over 100 different utilities take
advantage of that, and you can send more than ten
if you want to. If you send 20 engineers, it's $2,000
still $100 per person. That's the first big initiative to
bring more people on the show floor.

The second initiative is the Innovation Stage. As you

mentioned, we will have two of these innovation
stages set up on the Expo floor. Our Technical
Committee has chosen, I believe, 15 different
companies who will make presentations on these
innovation stages. The presentations will be on the
new technologies and what's new, with big data,
incorporating DERs onto the grid, and more.

The third initiative is the IEEE Smart Cities Pavilion.

There is a lot of talk these days about smart cities,
smart buildings and electrification of the
transportation system, which are some exciting
things happening in our industry. The IEEE Smart
Cities Pavilion will address these changes.

Wayne Bishop
You'll be happy to hear, we were supposed
to have our annual ISGT (Innovative Smart
Grid Technologies) conference in February in
Washington D.C., and of course, we had to cancel
that because of COVID. What we decided is to co-
locate ISGT in New Orleans in the Convention
Centre at the same time as T&D. We are going
to do our best not to have conflicting programs,
Alan Ross but T&D attendees will be able to sit in on ISGT
As a member of the IEEE Smart Grid program, presentations, and vice versa. ISGT attendees will
we are envious of smart cities getting their own also be able to attend T&D, and they have some
Pavilion. It has re-energized as well to focus on wonderful speakers lined up, including people
the 2023 Grid Edge Conference in San Diego. from FERC, NERC, and utility executives as well,
Photo: IEEE PES

I’m sure you’ll talk a little about that, and the talking about a lot of the trends that relate to
Innovative Smart Grid Technologies (ISGT) for smart grid and some of the big trends that are
this year. happening in our industry.
Transformer Technology February 2022 79

Issue 18

Alan Ross Wayne Bishop

How are you handling Covid rules? Since you Exactly, Alan, we want to reconnect safely, and we
are letting the city, is the city requiring you to want everyone to know that IEEE PES T&D will take
live by their compliance issues? your safety as the first priority, and our number
one priority. We will not only comply with all the
mandates of the city of New Orleans, but we’ll do
whatever else we need to do.

We are going to have the hand sanitizer stations

set up everywhere around the Convention Center.
If they mandate masks, which they probably will,
we'll have those on in the Convention Center.
There will be several events that will be partially
outdoors, like the opening session, or the opening
reception that will be on Monday evening, the 25th,
at the Mardi Gras Pavilion.

But they are ready for us and they are excited

about T&D. Registration is now open. The housing
block is open and there are good discounts
available. I'm extremely excited to be back in
person and I can't wait to see all my colleagues
ready to reconnect with everybody.

Alan Ross
For people in the utility industry, there’s an
excitement afoot with the change that is
taking place. AV charging is going to change
the grid. DER is changing the grid. An inverter-
based system is completely different. Solid
state technology is changing the grid. This Wayne Bishop
is probably the most exciting time since we The only other thing to mention is that T&D event
created the grid. There’s a lot happening is not a U.S. centric or North American centric show
around the world. and event. It's very much international. In normal
times, we would get over 90 different countries to
At APC Media, we are going to visit the attend and be represented. I think we'll easily have
showroom floor and we are going to learn 60 or 70 different countries represented this time.
about new technologies and share the You can go to the show floor, talk with the subject
value that IEEE brings. The 2023 Grid Edge matter experts at the exhibitor's booth and discuss
Conference and Expo is also going to build new concepts or products with them. You can now
the new foundation for IEEE PES, and people go to the innovation stages as a new initiative, or
should be excited to come and learn, come you can visit our IEEE Smart Cities Pavilion. This is
and share, or come and just network with each definitely not your same old T&D. It is something
other. for everyone. And now with ISGT being co-located,
it's even better. I am looking forward to seeing all
Wayne, any last thing that you want to share? our colleagues there in April.
Alan Ross
Wayne, thank you for the work that you do for
IEEE. All of the volunteers give so much, but
soon you are hooked because the giving that
takes place allows others to take knowledge Wayne Bishop
and understanding. IEEE is much more than a It really is. It's a big family of over 40,000 members
standards organization. Absolutely. strong.
Alan Ross
Wayne, it has been good to talk to you. See you Wayne Bishop
in April in New Orleans. Thank you, Alan.
80 CRITICAL
COMPONENTS
PROTECTION

Leading the Charge:

Coatings Stand on
Front Lines in Protecting
Electrical Components
by Maria Lamorey

Photo: iStock
Transformer Technology February 2022 81

Issue 18

Coatings are the first line of

defense to safeguard the critical
infrastructure from a variety of
conditions. Selecting the proper
coating materials to help preserve
power generators, transformers,
switchgear and more is crucial.

Maria Lamorey is a commercial strategy man-

ager at PPG. With over 20 years of industry
experience, Maria plays a leading role in PPG’s
commitment to delivering high-performance
coatings products across a variety of general
industrial applications including electrical
equipment of all types.
82 CRITICAL
COMPONENTS
PROTECTION

Millions of cars and trucks over the damaging pH (acid) levels, electrolytes,
next decade will be running solely on chemicals and ultraviolet (UV) light. According to the
electricity, while wind- and hydrogen-
based power sources continue to This type of corrosion typically starts Electric Power Research
gain momentum. In fact, 20% of all on sharp edges or an oddly shaped
electricity generation in the United part that may be difficult to coat.
Institute (EPRI), the
States came from renewables in In harsh environments, weaknesses on cost of corrosion-
2020, a number that is only expected areas like louvers and sharp corners
to increase. can lead to subsequent damage. related problems in the
That’s why high-edge coatings,
This growing demand, coupled with equipped with superior sharp edge
electrical industry
an aging power grid in the U.S., coverage, along with edge and face exceeded $17 billion
creates a need for an infrastructure corrosion protection properties,
built for longevity. Promising new can help to provide the exterior just a few years ago;
developments will help. The recent durability that electrical components
infrastructure bill has become law, require for reliability and longevity.
yet, roughly 20% or more
an act that allocates $65 billion in of these corrosion costs
support for our electric and grid For components such as transformers
infrastructure. that contain elements like oil, it’s are avoidable.
important to utilize coatings not only
While most electrical equipment holds for their corrosion resistance, but for
a minimum life expectancy of 20 years, their chemical-resistant properties.
many components are expected It’s also important to consider heat If the goal of an electrical equipment
to survive 50 years or more. Harsh dissipation and size when it comes manufacturer is to build next-
elements can accelerate corrosion to coating transformers. Some generation components that exceed
and leave sensitive instrumentation transformers, especially those that performance mandates while
vulnerable during storms and are larger, are required to be fully protecting its brand reputation, paint
compromise its reliability. Unfortunately, assembled prior to their last coat of specifications should be reviewed
many manufacturers still combine paint, then properly air-dried. High- and updated regularly. In addition to
old “cut-and-paste” specifications edge coatings help to ensure that product scope and substrate type,
that date back 20 to 30 years with even the hardest-to-reach parts manufacturers should address the
current industry-standard regulatory are covered. following criteria:
requirements written by IEEE, UL,
CSA and ASTM when painting and Smart Specification • Paint type
protecting new equipment. • Substrate preparation and
On average, finished electrical protection
Coatings are the first line of defense components are composed of about • Color
to safeguard this critical infrastructure 70% metal and 30% non-metal • Gloss
from a variety of conditions. Selecting substrates, yet nearly 100% of • Texture
the proper coating materials to electrical equipment manufacturers • Cure
help preserve power generators, view painting metal as beyond their • Product handling and storage
transformers, switchgear and more core competency. An average-sized • Performance
is crucial. According to the Electric switchgear manufacturer running 10 to
Power Research Institute (EPRI), the 15 million square feet of coated metal
cost of corrosion-related problems in through its facility is staking a lot of its
the electrical industry exceeded reputation on work considered outside High-edge coatings,
$17 billion as recently as just a few of their scope.
years ago. Yet, roughly 20% or more equipped with superior
of these corrosion costs are avoidable. Additionally, some equipment sharp edge coverage, an
manufacturers still base their paint
There is a wide range of coatings specifications solely on achieving edge and face corrosion
available that are engineered to a minimum industry standard or
preserve the future of our power according to a specification written by protection properties,
generation infrastructure. a paint supplier. Paint manufacturers can help to provide
often contribute to the problem by
Gaining an Edge designing coatings systems that the exterior durability
merely meet old specifications or
Metal substrates that typically achieve industry standards dictated that electrical components
comprise electrical components can by customers, instead of featuring the require for reliability
corrode for a number of reasons, newer technologies that provide better
Photo: iStock

including repeated exposure to high field appearance and anti-corrosive and longevity.
temperatures and humidity, properties.
Transformer Technology February 2022 83

Issue 18
84 CRITICAL
COMPONENTS
PROTECTION

Three’s Company weathering performance and (VOC) emissions, which can help to
operational attributes. These coatings achieve environmental compliance
When reviewing these specification are typically formulated with specific and reduce material usage, energy
criteria for electrical components, there resins combined to provide excellent consumption and maintenance costs,
are three major coatings technologies corrosion and chemical resistance, thanks to a first-pass transfer rate of
Photo: Wolv via Getting Images

that can be considered—powder, liquid as well as all-around application up to 85%.

and electrocoating formulations. versatility.
Liquid coatings use solvents or water
Powder coatings are formulated for Since powder coatings are made and are applied to pretreated metal
applications that require the ultimate without solvents, they generate with electrostatic spray, dipping and
combination of corrosion resistance, virtually no volatile organic compound other conventional methods before
Transformer Technology February 2022 85

Issue 18

If the goal of an electrical equipment

manufacturer is to build next-generation
components that exceed performance
mandates while protecting its brand
reputation, paint specifications should
be reviewed and updated regularly.
86 CRITICAL
COMPONENTS
PROTECTION

being air-dried or force-cured. When are the driving force behind most solutions for electrical equipment.
used as part of an integrated primer, specifications, color is also an It is important to consider several
pretreatment and topcoat system, important consideration. In fact, different factors to select a customized
liquid coatings offer exceptional corrosion and color are essentially coating system that is ideally suited
resistance to corrosion and chemicals, linked. The best-looking generators are for the project and based on specific
excellent sag resistance and strong the ones you can’t see, as weathered objectives, including:
adhesion. components that appear orange and
rusty are not aesthetically pleasing. • The specific region to determine
During the electrocoating process, how the weather will influence cor-
pretreated metal substrates are Transformers and generators that rosion, color fade, performance, etc.
immersed in an electrically charged are rusty often raise questions about • The specific substrate and shape
paint bath. Charged coating particles performance and effectiveness. to be coated; specific coatings are
form a tightly packed, insulating layer Coatings that help these components better for coverage on complex
that reaches every recessed area of the essentially blend into their environ- parts and sharp edges

Photo: Roemvanitch/EyeEm via Getty Images

coated part. At the end of the coating ments tend to be preferred, helping • Aesthetics and color
line, the metal part is baked, creating these components look the part and • Product longevity and life cycle
a tough finish that offers more withstand corrosive environments. requirements
thorough coverage.
Finding the Best Solutions Utilizing this information and working
Aesthetic Considerations with an industry expert can help
Electrocoat, pretreatment, powder and determine the best coating system for
While anti-corrosive properties liquid technologies are all great coating the project.
Transformer Technology February 2022 87

Issue 18
88 COMING
IN APRIL

New Design
and Advances
in Technology
When we were planning the themes for 2022, we
believed it was time to expand them beyond the “power
transformer” and the technical aspects relating to
those transformers, without moving too far afield.

The upcoming April digital magazine focuses on New

Design and Advances in Technology, with the following
suggested topics:

ADVANCES IN DRY TYPE TRANSFORMERS

FANS AND RADIATORS
GAUGES
PROTECTION SYSTEMS
CONTROL TRANSFORMERS
CABLES AND BUS WORK

Of course, at the heart of the power system is the transfor-

mer, so expect some great content from our community
members who consistently provide valuable technical
insight. And if you have an idea for an article, please
contact me at alan.ross@transformer-technology.com.
Alan Ross, Editor in Chief
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