How is the BDV test performed on transformer oil and why is it important?

The BDV test places an oil sample in a test cell with standardized electrodes and increases voltage until breakdown occurs. Several breakdowns are measured and averaged. It is important because it quickly indicates insulation strength and contamination level. Low BDV is often caused by moisture or particles and signals higher risk of discharge and faults, guiding decisions on dehydration, filtration, or deeper laboratory diagnostics.