What is the procedure for oil testing of transformer and what parameters are evaluated?

The procedure for oil testing of transformers involves sampling the insulating oil, followed by laboratory analysis. Key parameters evaluated include dielectric strength, moisture content, acidity, dissolved gas analysis (DGA), and furan analysis. Dielectric strength assesses insulation quality, while moisture content indicates potential degradation. Acidity measures oil degradation, DGA identifies fault gases, and furan analysis evaluates paper insulation condition. Regular testing ensures transformer reliability and longevity.