What is the process of transformer oil filtration method and when is it required?

The transformer oil filtration method involves the removal of impurities, moisture, and gases from transformer oil to enhance its dielectric strength and extend the lifespan of the transformer. This process typically employs vacuum filtration or centrifugal separation techniques. It is required when the oil shows signs of contamination, such as increased moisture content or decreased insulation properties, often indicated by routine testing or following maintenance activities. Regular filtration ensures optimal performance and reliability of power transformers.