Modern power systems rely heavily on transformers to deliver electricity safely and efficiently. However, one of the hidden threats to transformer reliability comes from the accumulation of dissolved gases in transformer oil. Over time, thermal stress, electrical discharges, and chemical reactions can degrade the insulating oil, leading to gas generation and compromising its insulating/cooling properties. That is why transformer oil filtration and purification are critical maintenance practices for any serious operator.

When a transformer runs under heavy load or encounters inadequate cooling, its oil can overheat. This overheating triggers the decomposition of oil molecules, producing gases such as hydrogen (H₂), methane (CH₄), and significantly ethylene (C₂H₄) — the latter being a strong indicator of overheating and insulation deterioration. In addition, electrical stresses like partial discharge or arcing can generate other gases (e.g., acetylene), further signaling serious faults.

Why is gas accumulation so dangerous? First, gas bubbles reduce the oil’s dielectric strength: when dissolved gases begin to come out of solution (e.g., under temperature or pressure changes), they form bubbles that substantially lower the insulating capability, potentially triggering partial discharges or even complete breakdown. Second, gas presence impairs heat transfer: the oil’s ability to cool the transformer’s core and windings diminishes, which can cause local hotspots, accelerating insulation aging.

Thus, transformer oil filtration plays a dual role: it removes not only solid contaminants and moisture, but also dissolved gases — restoring the oil’s electrical and thermal performance. A typical filtration/purification process involves vacuum degasification (to lower the pressure so dissolved gases escape), combined with heating and fine filtration to eliminate particles. By periodically applying such oil treatment, operators can forestall transformer failures, extend equipment life, and avoid costly downtime.

In conclusion, proper transformer oil maintenance — especially oil filtration and gas removal — isn’t a luxury, but a necessity for power system reliability. Monitoring for ethylene in transformer oil among other fault gases, and applying timely purification, ensures that deteriorating oil does not silently degrade transformer insulation — a vital step toward safe, long-lasting transformer operation.