Comparative study of partial discharge characteristics and dissolved gas analysis on palm-based oil as insulating material

Partial discharge (PD) properties and dissolved gas analysis (DGA) are investigated on two kinds of fatty acid alkyl esters synthesized from palm oil with additive, namely Pastell 2H-08 and Palm Fatty Acid Ester (PFAE) to be adopted in power transformers. For comparison, the properties of mineral oil which is commercially used transformer oil were also investigated in the research works. The results revealed that PD repetition rate number of the ester oils with additive increase remarkably at above 15 kV_rms of voltage application than that of mineral oil. PD charge of ester oils with additive tends to saturate at about 10,000 pC, while PD charge of mineral oil seems to keep increasing with increasing the applied voltage at above 20 kV_rms. The amounts of generated hydrocarbon gases in ester oils with the additive are higher than that of mineral oil. It is found that combustible gas pattern of the ester oils with the additive are different from that of conventional mineral oil. Duval analysis of ester oils with additive and mineral oil are classified as high energy electrical discharge, while for mineral oil is classified as low energy electrical discharge.