The minimum dielectric strength of transformer oil as per IS can be influenced by several factors, including the presence of impurities, moisture content, temperature variations, and the aging process of the oil. Additionally, the method of oil handling and storage can affect its dielectric properties, with contaminants reducing insulation efficiency. Regular testing with specialized equipment, such as those offered by Globecore, can provide crucial insights into the oil’s condition and dielectric strength, ensuring reliable transformer operation.