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Table 1. Multi Gas Family Comparison

KelmanTM MINITRANS Transfix DGA 500 Kelman TRANSFIX Kelman TAPTRANS

DIAGNOSTIC GASES

Hydrogen (H2)

Carbon Monoxide (CO)

Methane (CH4)

Ethane (C2H6)

Ethylene (C2H4)

Acetylene (C2H2)

OTHER GASES

Carbon Dioxide (CO2)

Oxygen (O2)

Nitrogen (N2)

OTHER PROPERTIES

Moisture (H2O)

Multi Gas DGAProduct Selector Guide

Transformers are expensive components of the electrical grid. Monitoring transformers is an increasingly vital tool of successful asset managers to enable them to gauge and address the risk in their network, but also to build a fact based asset replacement strategy.

When a transformer’s insulation system is overstressed, gases are produced that dissolve in the transformer’s insulating oil. Dissolved Gas-in-oil Analysis (DGA) and moisture measurements are recognized as the most important tests for condition assessment of transformers and the best early indicators of developing faults.

Multi-gas DGA analysis not only enables to precisely monitor the condition of a transformer but also to remotely diagnose the most likely cause and therefore severity of any health deterioration.

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Multi Gas DGA Monitors

Multiple methods of diagnostic have been developed and shown in standards such as IEEE® C57.104 and IEC® 60599 which allow users to relate measured gas in oil concentrations to potential on-going or developing faults.

Gas Name Condition Resulting is gas production

H2 Hydrogen Nearly all fault conditions, low energy PD

CH4 Methane Oil overheating between 200 and 500oC

C2H6 Ethane Oil overheating between 300 and 500oC

C2H4 Ethylene Oil overheating over 500oC, possible formation of carbon particles

C2H2 Acetylene Electrical arcing, Oil> 800oC, strong formation of carbon particles, metal melting

CO Carbon Monoxide Paper insulation overheating

CO2 Carbon Dioxide Severe oil oxidation, paper degradation

O2 Oxygen Oxidation, leak

Table 2. Fault conditions associated with individual diagnostic gases

Table 3. Product diagnostic methods and gases used

Duval’s Triangle

Duval’s Triangle

OLTC

Duval’s Triangle 4Low Temp

Faults

Duval’s Triangle 5

Japanese ETRA

Gas Ratio Rodger’s &

Doernenburg IEC / IEEE

EPRI OLTC Ratios

Key Gas Method TDCG

GASES USED

Hydrogen H2

Carbon Monoxide CO

Methane CH4

Ethane C2H6

Ethylene C2 H4

Acetylene C2H2

DIAGNOSTIC SUPPORT

Kelman MINITRANS

Transfix DGA 500

Kelman TRANSFIX

Kelman TAPTRANS

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Diagnosis based on DGA