Transformer oil does not just insulate and cool; it also acts as a diagnostic ledger for the health of the entire asset. Over time, electrical and thermal stresses break down the oil and surrounding paper insulation, generating volatile gases like hydrogen, methane, ethylene, and acetylene. When these dissolved gases build up, they lower the dielectric strength of the oil and can accelerate insulation breakdown.
This is where degasification within a modern oil filtration machine becomes critical. Degasification is the process of physically stripping these destructive dissolved gases—along with any dissolved moisture—out of the transformer oil, restoring its vital properties.
The Physics Behind the Process
How does a filtration machine pull dissolved gases out of a liquid? It relies on two main principles: vacuum and heat.
Thermal Conditioning: The oil is first gently heated to an optimal temperature, usually around 60 degrees Celsius. Heating lowers the oil's viscosity and decreases the solubility of the dissolved gases, making them easier to release.
Vacuum Chamber Exposure: The heated oil is then sprayed or distributed across specialized cascading elements inside a high-vacuum chamber. This dramatically increases the surface area of the oil.
The Boiling Effect: By exposing this thin film of oil to a deep vacuum, the boiling point of water and the vapor pressure of the dissolved gases drop significantly. The gases and moisture instantly flash off into vapors and are pulled out of the chamber by the vacuum pump, leaving behind clean, degassed oil.
Why Degasification Cannot Be Skipped
Attempting to filter transformer oil without a proper degasification stage is like cleaning a window while leaving the frame loose; you are missing the root of the problem. High gas levels can lead to gas bubbles forming under heavy loads, which can cause immediate electrical arcing and catastrophic failure.
Regular degasification during oil purification ensures that your dissolved gas analysis (DGA) baselines remain accurate, protects the internal paper insulation, and prevents premature asset failure. It is a fundamental pillar of proactive substation maintenance that directly translates to grid reliability.
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