How does a transformer oil BDV tester operate in laboratory testing?

A BDV tester applies an increasing AC voltage across a fixed gap between standardized electrodes immersed in an oil sample. The voltage rises at a controlled rate until electrical breakdown occurs, then the breakdown voltage is recorded. The test is repeated multiple times to obtain an average or specified statistic. Lab procedures control sample temperature, electrode cleaning, and agitation to reduce bubbles and improve repeatability. Calibration and correct method adherence are crucial, because electrode condition, moisture pickup, or improper gap setting can significantly distort results.