Breakdown strength of vegetable-based oils under AC and lightning impulse voltages

The breakdown strength of vegetable-based oil (VBO) and mineral oil is compared by means of experimental determination of breakdown voltage. These oils were tested under AC and positive lightning impulse voltages for uniform and non-uniform electrical field. The oil gap varied from 2 mm up to 85 mm. The results show same or higher AC breakdown strength of VBO compared to mineral oil for small gaps and uniform electrical field, whereas for lightning impulses and non-uniform field breakdown strength of VBO is reduced.