In order to investigate the changing rules of transformer oil interfacial tension during its aging process and find solutions to treat this unqualified oil

open-cup aging experiments for fresh oil were conducted at different temperatures.The mixing-oil test for unqualified oil with different ratios to fresh oil

and regeneration experiments for the unqualified oil with different amounts of adsorbents were carried out as well.The results show that

the interfacial tension is sensitive to indicate the oxidations content in oil not only in the initial stage of the aging process but also in the later stage

meaning the supervision of interfacial tension should be enhanced during oil monitoring process.When the interfacial tension exceeds the standard value

changing or regenerating the unqualified oil can solve the problem thoroughly.However

due to its high cost and no good at energy conservation and environmental protection

changing oil is not the best way.