Thermal stability change of synthetic ester-based transformer oil

For good transformer condition assessment it is necessary to determine the of insulating materials, both liquid and solid. Transformer reliable for as long its insulation system resists deterioration. Therefore, thermal oxidation stability are important characteristics oil. It a measure oil resistance decomposition by influence oxygen temperature. Oils with retain their regardless stress. Because environmental safety issues, use synthetic ester-based oils increasing. Although they have been in smaller transformers (distributive, traction, …) decades, limit values chemical physical still discussed. New methods evaluation can be useful assessment.