The oil inside the transformers has the function of cooling and insulation of the transformer. The amount of stress oil has to withstand is significantly increasing with the design optimization and it has increased more than 10 times in the past decades. At the same time, looking from the environmental aspect, the expected transformer oil lifetime is looking to be extended to reduce pollution and resources consumption. In order to achieve this high demands from environmental , economical and reliability aspect the oil quality can be improved by means of treatment . Evervac specializes in oil and SF6 treatment plans and is pushing the industry standards for oil treatment which at the same time does not damage the natural good characteristics of the transformer oil . .