What does BDV indicate about transformer oil quality?

BDV, or Breakdown Voltage, indicates the dielectric strength of transformer oil, reflecting its ability to withstand electrical stress without failing. A higher BDV value signifies better oil quality, indicating fewer impurities and moisture content, which enhances insulation properties. Regular BDV testing is essential for assessing transformer oil quality and ensuring reliable operation, as low BDV values can lead to insulation breakdown and potential transformer failure.