What does dielectric strength indicate in transformer oil testing?

Dielectric strength (BDV) indicates how well the oil resists electrical breakdown under a standardized test. Low BDV often points to moisture, particles, or dissolved contaminants that create conductive paths or bubbles. BDV is a screening indicator, not a complete health verdict. Good BDV does not guarantee low acidity or good oxidation stability. The most useful view is BDV trend plus moisture ppm, IFT, acidity, and DDF results.