What Transformer Oil Tests Are Performed?
Quick answer — Routine oil tests cover breakdown voltage (dielectric strength), moisture (water content), acidity (neutralisation value), dissolved-gas analysis (DGA), and often interfacial tension, power factor and the presence of PCBs. Together they detect moisture, aging, contamination and the thermal/electrical faults that DGA flags.
What oil tests are done on a transformer?
Condition tests
Breakdown voltage (BDV) tests the dielectric strength; moisture and acidity indicate the degree of insulation aging and the risk to dielectric strength; interfacial tension and power factor gauge the oil condition.
Fault diagnostics
Dissolved-gas analysis (DGA) measures the gases produced by thermal and electrical stress and is the key tool for detecting a developing fault.
When and why
Oil is sampled at commissioning and periodically afterwards, and more often if a fault is suspected or the unit is critical. The results are compared to limits and to previous results to track the trend.
References & standards
- IEC 60296 (oil)
- IEC 60599 (DGA)
- IEEE C57.104
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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