Effect of oxygen on oil decay products formation

It was believed that the increase in acid number is a forerunner of the formation of sludge, which is considered as a most detrimental chemical process. Now, more sensitive methods based on light absorption and diffraction (ASTM D6802 and D6181), can be used for detection of early stage sludge formation even at low acid number. In the present study, the effect of oxygen on the aging process of insulating systems in both hermitic and air breathing transformers has been simulated under controlled laboratory conditions, for different types of insulating fluids. The obtained results convincingly prove that paramagnetic nature of oxygen can adversely affect the dielectric properties of liquid and solid insulations used in power transformers.