Transformer Oil Analysis (DGA) for Early Fault Detection
Neva Otomasyon · 22.06.2026 · 6 min read
What Is DGA and Why It Matters
Dissolved Gas Analysis (DGA) measures the gases that build up in the insulating oil of a power transformer. Under electrical or thermal stress, oil and cellulose insulation break down and release gases such as hydrogen, methane, ethylene, acetylene and carbon oxides. The type of gas and how fast it accumulates reveal a developing fault long before any visible failure appears. Argus EMS watches these signals continuously, turning maintenance from reactive into predictive.
Which Gases Indicate What
Each gas points to a different fault mechanism. The table below summarises the relationships seen most often in the field:
| Gas | Likely Fault |
|---|---|
| Hydrogen (H₂) | Partial discharge, early degradation |
| Methane / Ethane (CH₄, C₂H₆) | Low-to-medium temperature thermal stress |
| Ethylene (C₂H₄) | High-temperature overheating |
| Acetylene (C₂H₂) | Arcing, high-energy discharge (critical) |
| CO / CO₂ | Cellulose (paper) insulation breakdown |
A marked rise in acetylene is the most critical warning; it indicates internal arcing and demands fast action.
How Results Are Interpreted
A single reading is rarely meaningful on its own; ratios and trends matter most. Common field methods are the Rogers ratio, the Duval triangle and the IEC 60599 threshold tables. These use gas ratios to classify a fault as thermal, partial discharge or arcing. Argus EMS combines raw gas values with these interpretation frameworks and gives operators a simple status, so even non-expert teams can grasp the risk quickly.
Periodic Lab Sampling vs Continuous Monitoring
Traditional DGA relies on drawing an oil sample and sending it to a laboratory, usually once or twice a year. While this catches slowly developing problems, it can miss a fault that grows quickly between two samples. Online DGA sensors make measurement continuous. Argus EMS reads these sensors over Modbus, tracks gas levels without interruption and raises an alarm the moment a threshold is exceeded.
Predictive Transformer Monitoring with Argus EMS
In Argus EMS, DGA data sits on the same screen as the transformer's load and temperature. Sudden jumps in the gas accumulation rate become visible through trend charts, and when a gas crosses its threshold the responsible team is notified automatically. In this way the Neva Otomasyon monitoring approach reduces the risk of unexpected failure and unplanned downtime, extends transformer life and makes the maintenance budget predictable.
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