Which diagnostic tests are included in transformers oil testing programs?

A typical program includes dissolved gas analysis, moisture content, dielectric breakdown voltage, acidity or neutralization number, interfacial tension, resistivity, and dissipation factor. Particle count and inhibitor content may be added for detailed quality control. For asset health evaluation, furan analysis helps estimate cellulose insulation aging. Trending results over time is critical because rapid changes can indicate developing faults such as overheating, arcing, or oil oxidation. Field screening tests may be combined with periodic full laboratory testing.