Comparative analysis of AC breakdown properties of Jatropha-based ester and other insulating oils: commercial natural ester, synthetic ester, and mineral oil

This article describes an experimental investigation into the AC dielectric strengths of a Jatropha-derived new natural ester (JNE) and compares it with equivalent commercial natural ester (CNE), synthetic ester (SE), and mineral oil (MO) used as a reference sample. The findings indicate that both JNE and CNE have comparable AC breakdown voltages of 74.5 kV and 70.3 kV, respectively, under the test conditions used in this study. However, they exhibit slightly lower breakdown voltages than SE, which displays a breakdown voltage of 79.2 kV. Nevertheless, their AC breakdown voltage is higher than that of mineral oil, which has a value of 68.1 kV. The breakdown voltages of natural esters decreased considerably by around 30% due to aging, unlike SE (~ 17%) or MO (~ 11%). Based on the statistical analysis of breakdown voltage data, it is observed that the Jatropha-derived natural ester (JNE) has a better voltage withstand capacity than the commercial natural ester (CNE) after aging, as the former only showed a 30% decline compared to a 48% decline in the latter.