Transformer oils deteriorate with time and the decay begins the moment the transformer oil is shipped from Manufacturer’s factory. High temperatures, the presence of oxygen and water, the catalytic action of the materials within the transformer, all combine to result in oxidation and cracking of the transformer oil.
The by-products of this oxidative process are acidic in nature, which results in an ever-increasing rate of deterioration of the transformer and its oil. This type of contaminated oil completely loses its insulating properties which will affect the life of the transformer in the long run.
Hence the insulation properties of transformer oils should be maintained periodically by filtering this oil .
The periodic and proper treatment of these insulating fluids will result in the improvement of the properties of the entire insulating system of power transformers and will extend the effective lifetime of the asset.
Many thousands of oil filled transformers containing huge quantities of insulating oil are in service today. As you are aware, the mineral oil in these transformers is intended to,
Provide dielectric strength of the transformer insulation system
Provide efficient cooling
Protect the transformer core and coil assembly from chemical attack
Prevent the build-up of sludge in the transformer
