Transformer oil filtration is the process of removing contaminants, such as moisture, particulate matter, sludge, and gases, from the insulating oil in transformers. The filtration helps restore the oil's dielectric properties, which are crucial for proper insulation and heat dissipation. Typically, the oil is passed through a filtration system equipped with various media like activated carbon or fine filters to purify it. Filtration may be done under vacuum or by using other methods such as centrifugal separation. Regular oil filtration is essential for maintaining transformer performance, preventing breakdowns, and extending the lifespan of transformers, especially in high-load or critical applications.