Signs (visual inspection)
Oil affected by “chemical degradation of oil” appears dark in color and sometimes with a pungent odour.The appearance may show signs of sediment or particulate matter.
In the case of internal inspection of the transformer, there are deposits of sludge at the bottom of the transformer casing, on insulating papers and in oil circulation ducts used for cooling the windings and the papers themselves.
Representative sampling
During external inspection of the transformer it is necessary to take representative samples of insulating oil in accordance with the reference standard and the operating instructions attached to the sampling kits (read more).
