A Dissolved Gas Analysis Investigation of Natural Ester under Electrical Breakdown Faults

Natural ester has been successfully put into commercial use in high voltage transformer in recent years for its advantages in fire resistance, biodegradation, etc. This paper presents experimental results of dissolved gas analysis(DGA) of natural ester under AC breakdown faults with and without oil-pressboard interface, and mineral oil were tested as comparison. The results revealed that more CO generated in natural ester than mineral oil after breakdown, and the proportion of fault gases changed when oil-pressboard interface involved. It was also found that significant amount of bubbles formed at pre-breakdown stage in case of creeping discharge on pressboard surface.