Under normal operating conditions, oils should not produce gases. However,
as energy (thermal or electrical) increases, the oil can not withstand such conditions and decomposes
generating gases.
International standard IEC 60422 has been prepared by IEC Technical committee
10: Fluids for electrotechnical applications.
List of IEC Norms
IEC 60156:
Insulating liquids – Determination of the breakdown voltage at power
frequency –
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Test method
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IEC 60247:
Insulating liquids – Measurement of relative permittivity, dielectric
dissipation factor
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(tan δ ) and d.c.
resistivity
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IEC 60296: Fluids
for electrotechnical applications – Unused mineral insulating oils for
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transformers and switchgear
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IEC 60475:
Method of sampling liquid dielectrics
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IEC 60666: Detection
and determination of specified anti-oxidant additives in insulating oils
|
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IEC 60814:
Insulating liquids – Oil-impregnated paper and pressboard – Determination of
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water by automatic coulometric
Karl Fischer titration
|
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IEC 60970:
Methods for counting and sizing particles in insulating liquids
|
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IEC 61125:
Unused hydrocarbon-based insulating liquids – Test methods for evaluating the
|
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oxidation stability
|
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IEC 61619:
Insulating liquids – Contamination by polychlorinated biphenyls (PCBs) –
Method
|
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of determination by
capillary column gas chromatography
|
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IEC 62021-1: Insulating
liquids – Determination of acidity – Part 1: Automatic potentiometric
|
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titration
|
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ISO 2049:
Petroleum products – Determination of colour (ASTM scale)
|
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ISO 2719: Determination
of flash point – Pensky-Martens closed cup method
|
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ISO 3016:
Petroleum products – Determination of pour point
|
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ISO 3104:
Petroleum products – Transparent and opaque liquids – Determination of
kinematic
|
||||||
viscosity and calculation of
dynamic viscosity
|
||||||
ISO 3675: Crude
petroleum and liquid petroleum products – Laboratory determination of
|
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density – Hydrometer method
|
||||||
ASTM D971-99a:
2004 Standard test method for interfacial tension of oil against water by the
|
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ring method
|
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Ref: IEC 60599 - International Standard
Why are Oil and Gas Analysis Important?
The insulating oil
in a transformer says a great deal about the actual condition of the transformer
as well as its remaining lifetime. Accurate information about the oil makes it
possible to anticipate potential failures and put in place a precisely targeted maintenance and/or replacement plan.
| Ref - http://www.laborelec.be/ |
How it works?
Sampling > Analysis > Interpretation > Recommendation
Analyse
|
Norms
|
Tension de rupture après filteration
|
CEI 60156
|
Tension de rupture
|
CEI 60156
|
Gaz Buchholz
|
CEI 60567
|
Couleur et apparence
|
ISO 2049
|
Soufre corrosif
|
CEI 62535 / ISO 5662
|
Soufre corrosif (après traitement à la résine)
|
CEI 60296
|
DBDS
|
CEI 62697
|
Degré de polymérisation
|
CEI 60450
|
Densité
|
ISO 3675
|
Facteur de dissipation
|
CEI 60247
|
Gaz dissous
|
CEI 60567
|
Furannes
|
CEI 61198
|
Gazage
|
CEI 60628
|
Inhibiteur (DBPC)
|
CEI 60666
|
Indice de neutralisation, l'acidité
|
CEI 62021-1
|
Stabilité à l'oxydation
|
CEI 61125
|
PCB
|
CEI 12766-2 / 61619
|
Résistivité
|
CEI 60247
|
Sédiments et les boues
|
CEI 60422
|
Viscosité
|
ISO 3104
|
La teneur en eau
|
CEI 60814
|
Note:
Gas formation is the consequence of an energy dissipation process.
Gas generation rate is a measurement of energy dissipation.
Transformer Oil Classification
Good Oils:
NN 0,00 - 0,10
IFT 30,0 - 45,0
Color Pale Yellow
OQIN 300 - 1500
Proposition A Oils:
NN 0,05 - 0,10
IFT 27,1 - 29,9
Color Yellow
OQIN 271 - 600
Marginal Oils:
NN 0,11 - 0,15
IFT 24,0 - 27,0
Color Bright Yellow
OQIN 160 - 318
Bad Oils:
NN 0,16 - 0,40
IFT 18,0 - 23,9
Color Amber
OQIN 45 - 159
Very Bad Oils:
NN 0,41 - 0,65
IFT 14,0 - 17,9
Color Brown
OQIN 22 - 44
Extremely Bad Oils:
NN 0,66 - 1,50
IFT 9,0 - 13,9
Color Dark Brown
OQIN 6 - 21
Disastrous Oils:
NN 1,51 or more
Color Black
Ref: http://www.satcs.co.za
Generated Gases
Hydrogen (H2)
Methane (CH4)
Ethane (C2H6)
Ethylene (C2H4)
Acetylene (C2H2)
Carbon Monodixe (C0)
Carbon Dioxide (CO2)
Origin of Gases
Cellulose Decomposition at working temperature (100°C - 110°C)
NN 0,05 - 0,10
IFT 27,1 - 29,9
Color Yellow
OQIN 271 - 600
Marginal Oils:
NN 0,11 - 0,15
IFT 24,0 - 27,0
Color Bright Yellow
OQIN 160 - 318
Bad Oils:
NN 0,16 - 0,40
IFT 18,0 - 23,9
Color Amber
OQIN 45 - 159
Very Bad Oils:
NN 0,41 - 0,65
IFT 14,0 - 17,9
Color Brown
OQIN 22 - 44
Extremely Bad Oils:
NN 0,66 - 1,50
IFT 9,0 - 13,9
Color Dark Brown
OQIN 6 - 21
Disastrous Oils:
NN 1,51 or more
Color Black
| Where | IFT - Interfacial Tension | ||
| NN - Neturalisation Number | |||
| OQIN - Oil Quality Index | |||
Generated Gases
Hydrogen (H2)
Methane (CH4)
Ethane (C2H6)
Ethylene (C2H4)
Acetylene (C2H2)
Carbon Monodixe (C0)
Carbon Dioxide (CO2)
Origin of Gases
Oil
|
Oxidation
|
||
Pyrolysis (overheating)
|
|||
Partial discharges
|
|||
Arcing
|
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Pyrolysis (Overheating)
Partial Discharges
Gas Formation Mechanism
With high temperature, chemical bonds break forming free radicals that recombine to form small and large molecules (gases, waxes).
Gas Evolution With Temperature
Gas Evolution With Temperature
Gases Generated During Breakdown of Dielectric Oil
Gases Generated During Breakdown of Cellulose Insulation
