When it comes to high-value electrical assets like transformers, early fault detection can mean the difference between a simple repair and a catastrophic failure.
That’s where the DGA Test comes in — a powerful diagnostic tool that helps identify the internal faults in a transformer before they escalate.
Here’s a detailed breakdown of the gases commonly detected during DGA and what they reveal about transformer health:
Types of Gases and Their Diagnostic Significance:
Gas Chemical Name Indication / Root Cause
H₂ – Hydrogen Partial discharges or corona activity. A key marker of incipient electrical discharges.
CH₄ – Methane Formed during low-temperature oil overheating (150–300°C). Often indicates hot spots or thermal faults in windings.
C₂H₄ – Ethylene Sign of moderate overheating (300–400°C). Suggests worsening thermal stress compared to CH₄.
C₂H₂ – Acetylene The most alarming gas! Associated with high-temperature arcing faults (>500°C), indicating potential internal arcing or severe insulation failure.
CO – Carbon Monoxide Comes from overheating of cellulose (paper) insulation. If detected, insulation aging or localized heating is a concern.
CO₂ – Carbon Dioxide Indicates slow thermal degradation of paper insulation at lower temperatures than CO. A good long-term aging indicator.
Why This Matters for Asset Managers and Engineers:
Preventive Maintenance: Detect issues early and avoid forced outages.
Root Cause Analysis: Different gases = different fault types.
Life Extension: Monitor insulation aging and optimize loading.
Safety & Reliability: Stay ahead of catastrophic failures.
Pro Tip: It’s not just about individual gases. The ratios between gases, their rate of increase, and absolute concentrations help pinpoint whether the issue is electrical, thermal, or incipient.
Kingrun Transformer Instrument Co.,Ltd.
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