What procedures are included in an oil transformer dielectric and BDV test?

A dielectric breakdown voltage test measures the oil’s ability to withstand electric stress without arcing. The procedure uses a standardized test cell with two electrodes at a fixed gap. The oil sample is poured carefully to avoid bubbles, then an AC voltage is ramped up at a defined rate until breakdown occurs. The breakdown value is recorded and the test is repeated multiple times, usually 5 or 6 shots, to calculate an average. Good practice includes cleaning the cell, controlling temperature, and filtering particles that can distort results.