Electrical properties and oxidation resistance of reclaimed transformer oils

All the measurements performed in the course of this study show that the oil aged up to the end of its induction period and reclaimed, is the only one whose oxidation resistance and characteristics in general were as good as that of the reference naphthenic oil used. From a practical point of view, transformer oils should not be allowed to age after their induction period, which can be determined by measuring their inhibitor content. It is at this stage that aged oils should be reclaimed. Reclamation performed at longer oxidation times (i.e. the standard procedure) never allows a full restoration of the oil´s original quality because it then contains too many nonacidic polar products.