How Is Transformer Oil Filtered and Regenerated?
Quick answer — Transformer oil is treated by passing it through a filter and a vacuum-degassing/regeneration plant that removes particles, water and dissolved gases, and in regeneration also removes acids, sludge and oxidation products. The result is a cleaner, drier, higher-BDV oil that restores the dielectric strength and slows aging. The oil is then returned or the unit filled/refilled under vacuum.
How is transformer oil filtered and treated?
Filtration
Mechanical filters remove particles, and a vacuum plant removes water and dissolved gases, raising the BDV and reducing the moisture.
Regeneration
Regeneration (e.g. with a fuller earth or clay system) also removes acids, sludge and oxidation products, restoring the oil closer to new condition.
When and how
Oil is treated when the BDV, moisture, acidity or DGA drift; the process is done on-line or off-line, often while the transformer is out of service, and the unit is then re-filled under vacuum.
References & standards
- IEC 60296 (oil)
- IEC 60076-1
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
Related components
Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
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