3. 1
1
Training & Education
Online Classroom
2
Wrap Up
Principles of Transformer Maintenance
Session 12
3
Wrap Up
Putting Together Your Maintenance
Program
Things to Remember
4. 2
Your Instructor
Training & Education
Instructor
Former Health & Safety
Director, Mobile Diagnostic
Technician
Curriculum Development
Coordinator
28 Years in Transformer
Industry
Mark Stone
Wrap Up
• What results would you like to see from a
Maintenance Program?
o Predict failures
o Extend reliable life
o Predict the end of reliable life
o Save money
5. 3
Maintenance Practices
• Three types of maintenance practices:
o Reactive maintenance
• Corrective - when something is broken, fix it
o Preventative maintenance
• Scheduled maintenance - intended to postpone or prevent
the need for corrective action
o Predictive maintenance
• Information from testing and operations identify probable
future needs to forestall abnormal conditions
Transformer Maintenance
Overview
• Identify areas where maintenance needs arise
• These areas are divided into three categories:
o Mechanical
o Electrical
o Chemical
MaxLife Philosophy
To manage transformers intelligently, our goal is to
provide maximum cost effective and reliable life
to substation equipment while preventing
unplanned outages.
• This includes, but is not limited to:
o Sludge-free operation of transformers
o Effective insulating liquid
o Electrical testing for monitoring and diagnostics.
6. 4
Sludge-Free Operation
• All test results are kept within Acceptable limits
by appropriate testing and timely maintenance
o Minimizes damage to the solid insulation
o Maximizes reliable life of the equipment
• Timely and appropriate maintenance
contributes to effective life extension and
responsible optimization of reliability.
Wrap Up
Things to Remember
How Much Do You Retain?
• 10% of what you hear
• 25% of what you see and hear
• 75% of what you see, hear, and DO
7. 5
Choose 1or 2 Things You Learned
and Implement Them
• You may need to
o Teach them to your boss in order to get approval
o Teach co-workers, especially if you need help in getting them
implemented
• You already know more than you think you do
• You have the tools to learn more
• As you have success getting things done, expand
the scope of what you are doing – gradually
Things to Remember
• The life of the paper is the life of the transformer!
• The most critical function of the insulating liquid
o Protect the solid insulation
• As oil ages and oxidizes
o It no longer fulfills this most critical function
Things to Remember
• Maintaining the transformer in “sludge free”
operation (all oil test results AC)
o Is critical to proper equipment operations and
maintenance
• A reinhibiting strategy
o Is the most cost effective means of maintaining “sludge
free” operation
8. 6
Things to Remember
• Many factors act together to accelerate the
aging of oil and breakdown the paper
• Controlling the conditions and factors we can
has a profound impact on extending the life of
the oil and the equipment
Things to Remember
• Engineering controls help control
o Entry of moisture
o Exposure of the oil to oxygen
o These oil preservation systems need to be tested and
maintained
• Operating temperatures are a critical factor in
both oil and paper aging
Things to Remember
• Transformers need to be dry when they are first
energized (Use an acceptance value of 0.5%
M/DW)
• Transformers need to be kept dry
o double the moisture content of the solid insulation, you half
the life of the insulation life
9. 7
Things to Remember
• More than 99% of all of the moisture in a
transformer is in and on the paper rather than
being dissolved in the oil
• Drying out the oil is easy . . . Drying out the
transformer is more difficult (and MUCH more
important)
Things to Remember
• All transformers will fail, eventually
o The large majority of transformer failures (rule of thumb is
85%) are caused by aging of the solid insulation
• Other, largely preventable, causes of failure
include
o Transformer faults
o Dielectric failure of the oil
Things to Remember
• No single test
o Will consistently provide an owner with all of the
information needed to intelligently manage transformers
• Oil tests, dissolved gas analysis, routine and
diagnostic field electrical tests, and infrared
thermography all contribute to transformer
predictive maintenance
10. 8
And Finally
• Changing the oil in a transformer
o Will almost never be a permanent solution to a transformer
problem
• Confirm abnormal test results
o Before committing time, effort, and resources to a
“solution”
And Finally
• If a transformer has an active fault, it is rarely a
good idea to perform oil maintenance without
correcting the fault first
• For most of the testing we do, changes in values
and especially the RATE of change in values
are more important than the raw numbers
24
Wrap Up
Putting Together Your Maintenance
Program
Things to Remember
11. 9
25
Wrap Up
Principles of Transformer Maintenance
Session 12
26
Training & Education
Online Classroom
Thank you!
sdmyers.com/training
