Revitalization is a complex process that aims at overall improvement of transformer insulation parameters and involves the simultaneous or sequential execution of the following operations:

•  Desludging of the transformer active part
•  Drying of solid insulation
•  Oil regeneration

Desludging is a process for removal of sludge and oxidation by-product from transformer insulation and from the inside of dirty transformers. This process is done by heating naphthenic transformer oil up to its aniline point (the point where the oil will act as a solvent on the sludge it comes in contact with). The passing of the dissolved sludge through an adsorbent filter bed traps the sludge, removing it from the oil, paper and tank.