WELCOME T O A COMET 2017 · COMET 2017 1 COMET 2017 WELCOME T O A TECHNICAL PAPER PRESENTATION ....
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1 C O M E T 2 0 1 7 C O M E T 2 0 1 7 W E L C O M E T O A TECHNICAL PAPER PRESENTATION
Transcript of WELCOME T O A COMET 2017 · COMET 2017 1 COMET 2017 WELCOME T O A TECHNICAL PAPER PRESENTATION ....
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C O M E T 2 0 1 7 W E L C O M E T O A
T E C H N I C A L P A P E R P R E S E N T A T I O N
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B Y R A N D Y C O X
“Analytics for Dissolved Gas
Analysis”
Randy Cox is the Domain Expertise Manager for GE Grid Solutions,
M&D. His current duties include interfacing with the industry, committee
work and education of customers on the technical advantages of GE
M&D technology, products, software and solutions.
Randy is also a current member of IEEE.
A B O U T T H E A U T H O R
R a n d y C o x D O M A I N E X P E R T I S E M A N A G E R
G E G R I D S O L U T I O N S
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ABSTRACT SUMMARY
O V E R V I E W &
D isso lved Gas Ana lys is has p roven to
be one o f the mos t use fu l too ls in
ana lyz ing the cond i t i on o f o i l f i l l ed
power t rans fo rmers . By observ ing the
d isc ree t va lues o f the va r ious
combus t ib le gases , deve lop ing fau l t s
can o f ten be de tec ted in the i r ea r l y
s tages . In recen t years i t has been
d iscovered tha t t rend ing the CO2/CO
ra t io , over t ime , can a lso be very
use fu l i n p red ic t ing a t rans fo rmer ’s end
o f l i f e . By t rend ing th i s ra t io , i t may
a lso be de te rmined whether the
sever i t y o f an inc iden t i s l i f e end ing , o r
s imp ly an i so la ted even t .
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THE RELEVANT GASES
It is important to d is t inguish and
categor ize the gases. This is v i ta l in our
effor ts to d iagnose issues wi th in a power
t ransformer.
Hot meta l gases are wel l known and
understood by the industry. However, the
carbon ox ide gases (carbon d iox ide and
carbon monoxide) have cont inued to be
problemat ic for the average technic ian.
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TRADITIONAL RATIOS FOR KEY GASES U S E F U L I N D U S T R Y T O O L S
U T I L I Z I N G I N D U S T R Y T O O L S Industry tools can be very useful for
determining the temperature of a given fault, or
post-trip fault. While determining the
temperature of the fault is important, another
important piece to this puzzle is determining
the location of the fault. Faults which occur in
the winding insulation are not conducive to on-
site repairs, while overheated connections
(such as a de-energized tap changer) may
make an on-site repair possible.
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TRADITIONAL DATA EVALUATION
T H E T R A D I T I O N N A L V I E W
As gases begin to generate, we determine what the temperature of the fault is based on
individual levels and rate of change
D I S C R E E T VA L U E S
Early pioneers of DGA created charts with HMG ratios for us to calculate so that we could
distinguish partial discharge from overheating
H O T M E TA L G A S R AT I O S
Industry standards, such as IEEE and CIGRE’ provide guidance with a specific range
where the ratio is considered to be normal
S N A P S H O T C O 2 / C O R AT I O
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Y O U R T I T L E H E R E
Y O U R T I T L E H E R E
0
10
20
30
40
50
60
70
80
90
test1 test2 test3 test4 test5 test6 tes 7 test8 test9 test10
oil flash
oil w/paper CO2/CO RATIO
CO2/CO RATIO EXPERIMENT S E T T I N G U P T H E T E S T The testing was performed utilizing a
D877 oil tester, which holds a very small
amount of oil, about the size of a coffee
cup. New oil was used for each test.
First, oil was flashed, a DGA collected
with CO2 and CO measured and the
appropriate ratio reflected. Next, the oil
test cup was flushed with new oil, then
another sample of new oil added, but
this time with a single piece of
transformer Kraft paper added between
the electrodes with the test repeated.
The test was repeated a total of 10
times.
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Y O U R T I T L E H E R E
Y O U R T I T L E H E R E
0%
5%
10%
15%
20%
25%
30%
35%
40%
H2 CH4 C2H6 C2H4 C2H2
0%
5%
10%
15%
20%
25%
30%
35%
40%
H2 CH4 C2H6 C2H4 C2H2
Nitrogen Sealed #2 – 30 MVA Nitrogen Sealed #1 – 36 MVA
0
20
40
60
80
100
120
Pre Event
Post Event
0
1
2
3
4
5
6
7
Pre Event
Post Event
CO2/CO CO2/CO
CATEGORIZING FAULTS
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Primary Lead – Repairable #2 Winding Failure #1
Transformer Replaced Transformer Repaired
CATEGORIZING FAULTS CONTINUED
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CATEGORIZING EVENTS
Failed the following year, 2014
1850 ppm 200 ppm
2136 ppm 21 ppm
0
50
100
150
200
250
2008 2009 2010 2011 2013
CO
CO
1700
1800
1900
2000
2100
2200
2008 2009 2010 2011 2013
CO2
CO2
0 20 40 60 80
100 120
2008 2009 2010 2011 2013
C2H6
C2H6
0
20
40
60
80
100
120
2011 2013
CO2/CO Ratio
2011 2013
Failed the following year, 2014
1850 ppm 200 ppm
2136 ppm 21 ppm
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Date H2 O2 CO2 CO CH4 C2H6 C2H4 C2H2 CO2/CO
2011 <2 845 579 8 5 6 2 <1 72.3
2012
<2 831 524 5 2 4 1 <1 104.8
2013 <2 509 226 3 1 <1 <1 <1 75.3
2014 <2 1092 178 6 1 <1 <1 <1 29.6
2015 <2 500 124 10 2 1 <1 <1 12.4
0
20
40
60
80
100
120
140
1 2 3 4 5 6
CO2/CO 83% Drop
M
1999, 15 MVA, 100 kV TRANSFORMER
0
10
20
30
40
50
60
70
80
2011 2015
CO2/CO
2011 2015
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1999, 15 MVA, 100 kV, Complete Picture Date H2 O2 CO2 CO CH4 C2H6 C2H4 C2H2 CO2/CO
2011 <2 845 579 8 5 6 2 <1 72.3 2012 <2 831 524 5 2 4 1 <1 104.8 2013 <2 509 226 3 1 <1 <1 <1 75.3 2014 <2 1092 178 6 1 <1 <1 <1 29.6 2015 <2 500 124 10 2 1 <1 <1 12.4
2016 post fault 212 802 1188 414 210 72 372 422 2.8
0
20
40
60
80
100
120
140
1 2 3 4 5 6
CO2/CO
CO2/CO Linear (CO2/CO)
96% Drop 2011 - 2016
0
10
20
30
40
50
60
70
80
2011 2016
CO2/CO
2011 2016
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SUMMARY • Trending the CO2/CO ratio is a useful tool for detecting breakdown of the solid insulation. • The CO2/CO ratio appears to provide insight into deteriorating insulation in the absence of
hot metal gases. • The CO2/CO ratio is also useful in determining if an incipient fault is occurring in the winding
insulation, or perhaps a more repairable location, such as a DETC, bushing connection, etc. • This method is also useful in determining the need for offline testing, as well as the effect
loading may have on the solid insulation. • Trending of the carbon oxide ratios is most reliable when performed over time, using multiple
samples. • Special attention should always be given to all gases measured, including oxygen and
nitrogen.
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P A P E R Q & A C O M E T | C O L L A B O R A T E | S H A R E
K N O W L E D G E | P R O G R E S S
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9 7 2 - 6 3 2 - 0 2 6 6 L I N K E D I N
RANDY COX .
GE Gr id Solut ions
Moni tor ing & Diagnost ics
GET IN TOUCH
R . C O X @ G E . C O M
