Oil oxidation in impregnated paper

MUCH HAS BEEN written recently on the influence of oil oxidation on the properties and stability of impregnated paper insulation. It is thought by many to be a principal cause of deterioration in high voltage cables. Oxygen is highly soluble in cable oils; if present in appreciable quantity and at moderate temperature elevation, the oils oxidize rapidly with consequent loss of insulating value. However, the amount of oxygen remaining in a carefully dried paper cable is so small, and the oxidation process is so slow that it remains to be proved that it is more important in deterioration than other well-known causes.