When the oil in a transformer reaches a stage (due to ageing) where No Maintenance (purification and degassing) have been carried out. Regeneration is the complete treatment of oil back to a “like new condition”. Regeneration addresses the question of Acidity – this is on Transformer oils found to have an Acidity reading more than 0.2NN. Acidic Oil is the “Cancer” which if left unattended and uncorrected attacks the Solid Insulation Materials rendering them brittle and vulnerable to moisture ingress, debilitating the function of the Solid Insulation components.
Deterioration of the Solid Insulation continues apace until ultimately the transformer fails expensively and avoidably!!!!!
Dielectric Strength: Improvement of dielectric strength (kV)
Acid Removal: Equitable to that of Virgin Oil 0.03NN (Once in a 6/7-year Treatment)
Particle Removal: Remove impurities in suspension.
Why is Regeneration necessary?
As oil ages in a transformer, it oxidises and begins to break down. Some of the by-products of this degradation are:
Acids
Aldehydes
Peroxides
These bind together and form sludge. The sludge attacks the chemical bond, which holds the cellulose insulation together (measured by polymerisation).
When the oils neutralisation number is as low as 0.05, the cellulose insulation is already beginning to weaken. Since the cellulose insulation can only be replaced with a rewind, and the resultant loss of production, it makes sense to remove the oxidation by-products before they damage the cellulose. Since any degradation of the cellulose that occurs cannot be reversed, it is best to remove the oxidation by-products on a regular basis.
The life of the transformer is the life of the cellulose insulation.