what is the limit of normal breakdown voltage of transformer oil?

The limit of normal breakdown voltage for transformer oil typically ranges from 30 to 50 kV per centimeter of thickness. This value can vary based on the oil’s purity, temperature, and presence of contaminants. Regular testing for breakdown voltage is essential to ensure the oil’s insulating properties remain effective, as lower values may indicate degradation or contamination, compromising the transformer’s performance and safety.