What laboratory procedures are used in transformer oil testing and DGA?

Procedures start with controlled sampling to avoid air ingress and contamination. In the lab, oil is tested for breakdown voltage, moisture, acidity, interfacial tension, resistivity, and dissipation factor using standardized methods. For DGA, gases are extracted from oil by vacuum or headspace techniques and measured with gas chromatography. The lab reports individual gas concentrations and ratios used for diagnostics. Quality assurance includes calibration, reference standards, duplicate samples, and strict sample handling documentation.