DGA - Method
in the Past and
for the Future
Ivanka Atanasova-Höhlein
© Siemens AG
Page 2
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
1970
Doerenburg introduced the differentiation between electrical
and thermal failure mode and introduced ratios for fault gases
with similar solubility.
1973
Halstead developed the theoretical thermodynamic theory. The ratios
are temperature dependent. With increasing the hotspot the amount
of gases increases in the order: methane-ethane-ethylene.
1975
The evaluation scheme of the modern Gas-in-Oil Analysis is
developed by Rogers, Mueller, Schliesing, Soldner (MSS).
1995
Development of In-Line Monitoring
Page 3
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Different phenomena in oil take place like:
dielectric
thermal
Change/Ageing
dynamic
chemical
! Gas-in-Oil Analysis (DGA = Dissolved Gas Analysis)
Page 4
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
The measurement of dissolved gases
allow the knowledge on
!
Type
!
Complexity
!
Seriousness
of event
Page 5
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Sampling
Page 6
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Sampling Container
! Perfectly cleaned & Dried
! Free from dust & moisture
! Airtight
! Glass or Metal cans, syringes
Page 7
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
! Protect sample from direct light
! Avoid moisture & dust contamination
! Use the sampling containers exclusively
for transformer oil sampling
Page 8
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
1 Handwheel
2 Sealing cap
3 Safety chain
4 Polyamid gasket
5 Nut
6 Drain valve
7 Hose and screw connector
8 Sampling bottle
9 Overflow vessel
Page 9
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Page 10
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Required information concerning oil sample(example)
Requested analysis:
Colour
ISO 2049
Appearance
IEC 60422
Neutralisationvalue
IEC 62021-1
Breakdownvoltage
IEC 60156
Water content
IEC 60814
Loss factor at50Hz
IEC 60247
Interfacial tension
ISO 6295
PCB-content
EN 12766-2
Furananalysis (DGA)
IEC 61198
Gas-in-oil-analysis
IEC 60567
Please fill in the following data:
Manufacturer:
FTNR (ManufacturingNo.):
Customer:
WNR (Order No.):
Location:
SampleNo.:
Year ofmanufacture:
Datesampletaken.:
Type:
Typeofoil
Power:
Quantity ofoil:
Rating:
Oiltemperaturein thesampletaken:
Sampletaken from:
Oil samplevalve
Oil drainagedevice
A 22/31/40DIN 42551
Others
Tank:
Top
Middle
Bottom
conservator
Transformer
OLTC
Bushing
OLTC
OLTC tank
Bushing
Others:
Reason for sampletaking:
Dateofoperationfault:
Dateofrepair :
Dateofoil treatment/reclaiming
Routinecheckup:
Further informations andprevious history:
Sampletaker:
Date
Lab information:
Page 11
Consecutiveno.:
Datesamplereceived:
Datesampleanalysed:
Typeofsamplecontainer:
May 2012
Nameinblock letters
Company/Department
Phone
specialfeatures:
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Extraction of Gases
from the Oil
Page 12
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA. Toepler Pump
Page 13
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA. Partial Degassing
Page 14
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA. Headspace at Ambient Temperature
Page 15
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA. Headspace at 70°C
Page 16
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Gaschromatographic Analysis
Page 17
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Gaschromatographic Analysis
Sample
injection
Carrier
Gas
Page 18
May 2012
Detector
Detector
gas
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Failures which can be identified by DGA
! Partial discharges
! Electrical discharges
! Charcoal coating of contacts
! Accelerated cellulosic degradation
! Local overheating
! Untightness of OLTC tank
! Catalytic reactions of materials
! Additional information from BHR gas
Page 19
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Failures which can not be identified by DGA
! Incipient Failures
! Long lasting temperatures < 150 °C
Page 20
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Interpretation Schemes
Page 21
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Duvals Triangle
Page 22
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Patterns
Electrical Discharges
Page 23
May 2012
Thermal Problem
Ivanka Atanasova-Höhlein
Partial Discharges
© Siemens AG
Energy Sector
MSS Scheme
Ratio ranges
<0.3
0.3 to < 1.0
1.0 to < 3.0
3.0 to < 10.0
! 10.0
Diagnosis
Normal ageing of insultans
Discharge of high energy
Discharge of low energy
Partial discharge with high energy
Partial discharge with low energy
Local overheating up to 300 ºC
Local overheating from 300 ºC to 1000 ºC
Local overheating over 1000 ºC
Local overheating and discharge
Local overheating and partial discharge
[C2H2]
[C2H6]
0
1
1
2
2
0
2
2
1
1
0
0
1
1
0
n.i. = not indicative
Page 24
May 2012
Ivanka Atanasova-Höhlein
Ratio numbers
[H2]
[C2H4]
[C2H4]
[CH4]
[C2H6]
[C3H6]
0
0
0
0
0
1
1
1
2
2
1
3
3
1
3
Number sequences
0
0
0
1
1
2/3
2
1
2/3
3
0
n.i.
3
0
n.i.
0
0
1
0
1
2
0
1
2/3
1
1
2
3
1
2
[CO2]
[CO]
1
1
1
0
2
0
1
1
0
0
2
2
2
2
2
© Siemens AG
Energy Sector
IEC Scheme
Page 25
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
In case of quotient information it must be clear, that quotients
are only representative, if following values of the fault gases
(in ppm) are exceeded:
Page 26
May 2012
C2 H 2
!1
H2
! 15
" [CXHY] x=1;2;3
! 50
CO
! 80
CO2
! 200
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA
Example – thermal Problem
MSS-Code
00120
Fault gas
ppm
Hydrogen
H2
1967
Methane
CH4
8008
Ethane
C2H6
2013
Ethylene
C2H4
8323
Acetylene
C2H2
57
Propane
C3H8
401
Propylene
C3H6
4824
Carbon monoxide
CO
253
Carbon dioxide
CO2
1903
Oxygen
O2
18222
Nitrogen
N2
61662
Page 27
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
MSS-Code
00120
Fault gas
ppm
Hydrogen
H2
Methane
CH4
1041
Ethane
C2H6
295
Ethylene
C2H4
1726
Acetylene
C2H2
25
Propane
C3H8
83
Propylene
C3H6
1012
Carbon monoxide
CO
1047
Carbon dioxide
CO2
6158
Oxygen
O2
11805
Nitrogen
N2
58084
Page 28
May 2012
Manufacturing year 1970
360 MVA
Carbon deposits on PLTC Contacts
537
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Gas-in-Oil Analysis
Turn-to-Turn Fa
MSS-Code
21121
Fault gas
ppm
Hydrogen
H2
4973
Methane
CH4
1758
Ethane
C2H6
243
Ethylene
C2H4
2813
Acetylene
C2H2
8236
Propane
C3H8
58
Propylene
C3H6
1320
Carbon monoxide
CO
1196
Carbon dioxide
CO2
2431
Oxygen
O2
6743
Nitrogen
N2
44120
Page 29
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA
Thermal Problem with Partial Discharges
MSS-Code
00101
Fault gas
ppm
Hydrogen
H2
1060
Methane
CH4
2481
Ethane
C2H6
703
Ethylene
C2H4
2187
Acetylene
C2H2
4
Carbon monoxide
Carbon dioxide
CO
CO2
Page 30
May 2012
Manufacturing year 1991
234 MVA, 330 kV
Defective welding joint
450
995
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA
Catalytical Effects
MSS-Code
?3??0
Fault gas
ppm
Hydrogen
H2
Methane
CH4
Ethane
C2H6
<1
Ethylene
C2H4
<1
Acetylene
C2H2
<1
Propane
C3H8
<1
Propylene
C3H6
<1
Carbon monoxide
CO
67
Carbon dioxide
CO2
222
Oxygen
O2
5180
Nitrogen
N2
23700
Page 31
May 2012
Manufacturing year 1977
Closed type
Color 0,5 / Acidity 0,01
488
1
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA
Untight OLTC
MSS-Code
22122
Fault gas
ppm
Hydrogen
H2
Methane
CH4
25
Ethane
C2H6
5
Ethylene
C2H4
81
Acetylene
C2H2
288
Propane
C3H8
5
Propylene
C3H6
50
Carbon monoxide
CO
143
Carbon dioxide
CO2
1920
Oxygen
O2
24600
Nitrogen
N2
52000
Page 32
May 2012
128
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
DGA
Diagnostic Importance in Service
Page 33
May 2012
Ratios
Gas
increase
rates
Absolute
Values
Trend
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Absolute Values
IEC 60599 (VDE 0370-7)
C2H2
All transformers
No OLTC
2
"
20
Communicating
OLTC
60
"
280
Page 34
May 2012
H2
CH4
C2H4
C2H6
CO
CO2
50
"
150
30
"
130
60
"
280
20
"
90
400
"
600
2800
"
14000
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Ratios
a) Eliminates the effect of the oil volume
b) Eliminates some effects of sampling
c) Especially interesting is the ratio formation for fault
gases which exhibit similar solubilities, but their
development is temperature dependent –
e. g. the thermodynamic considerations of Halstead.
Page 35
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Thermodynamcal considerations of Halstead
Page 36
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Gas Increase Rates –
information on seriousness of failure
C2H2
All
0,01
transformers
H2
CH4
C2H4 C2H6
CO
CO2
0,36
0,33
0,40
2,9
27
0,25
! 90% gas increase source: Cigre TF11 in ppm/day
Gas increase rates are temperature and volume dependent
Page 37
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Trend Analysis
Development of the Fault Gases After Two Months of On-Line Monitoring
100
600
500
80
70
400
ppm CO 2
60
50
300
40
200
30
20
100
ppm H 2, CO,CH 4, C2 H4, C2 H6, top oil (°C)
90
Carbon Dioxide
Hydrogen
Methane
Carbon Monoxide
Ethane
Ethylene
top oil temp °C
10
0
1.7.08
0
11.7.08
21.7.08
31.7.08
10.8.08
20.8.08
30.8.08
9.9.08
Sa m pling da te
Page 38
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Trend Analysis
40
6
35
5
4
top oil (°C)
25
20
3
15
2
40
6
Ratio C 2H 4/C 2H 6, CH 4 /H2
30
10
1
35
5
5
30
0
top oil (°C)
20
3
15
2
1.7.08
Ratio C 2H 4/C 2H 6, CH 4 /H2
4
25
0
11.7.08
Top oil Temperature (°C)
21.7.08
31.7.08
10.8.08
20.8.08
30.8.08
9.9.08
Sa m pling da te
C2H4/C2H6
CH4/H2
10
! Trendanalysis is important not only with absolute values,
but also with the ratios.
1
5
0
1.7.08
0
11.7.08
21.7.08
31.7.08
10.8.08
20.8.08
30.8.08
9.9.08
Sa m pling da te
Page 39
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Top
C2H
CH
On-Line Monitoring
# Early failure recognition
# Diagnosis is only possible with the sofisticated types – where IEC
ratios can be built
Cigre TF 15 DGA did a comparison between On-Line monitoring
systems and Off-Line analyses. The brochure is on the way.
Evaluated are:
" Precision
" Longterm stability
" Repeatability
In case of
" Routine concentrations, d.h. 5 * Detection Limit
" Low Concentrations, d. h. 2-5*Detection Limit
Page 40
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Recommendation of Cigre A2.27
for On-LineMonitoring
# Necessary in case a problem has been identified
# Often, however, difficult to maintain
# Interfaces can lead to problems
# Able to deliver important information
in a short time
# Does not automatically lead to higher reliability
Page 41
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
What can be measured on-line:
! Temperature
! Current, Voltage
! OLTC
! Oil level
! Gas-in-Öl Analysis
! Humidity in oil
! Bushings
! Acoustic Signals
! Magnetic Circuit
! Coolers
Page 42
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
More Data does not mean automatically
more Information
Data Explosion1) (Total Exabytes)
200
150
100
50
0
2002
2003
2004
2005
1) Exa = 1016 = 10 Mil of Billions
Page 43
May 2012
Ivanka Atanasova-Höhlein
2006
2007
© Siemens AG
Energy Sector
Transformer Failure Rate
$ Failure rate
Failure at
Comissioning
Failure because
of aging
Constant failure rate
Page 44
May 2012
Ivanka Atanasova-Höhlein
Aging / years %
© Siemens AG
Energy Sector
Future Developments
# Further development of the On-Line analysis
with decision criteria
# Gas-in-oil analysis in OLTC
# Gas-in-oil analysis in alternative insulation fluids
and high temperature insulating materials
Page 45
May 2012
Ivanka Atanasova-Höhlein
© Siemens AG
Energy Sector
Thank you
for your attention!
© Siemens AG