Mineral insulating oils ageing monitoring by modified oxidation induction time

A method to determine mineral insulating oils remaining useful life by following oxidation induction time (OIT) using a test method originally applied to vegetable oils and biodiesel fuels was developed. When applied both to laboratory aged samples as well as actual in-service oil samples the method proposed in this work showed a variation proportional to ageing time, allowing the prediction of an end point for oil oxidation resistance.