Effect of mixing ratio on the breakdown voltage of mineral and natural ester insulating oil blends

To date, the most common insulating oil used in oil-immersed transformers is mineral (MI) oil, which derived from petroleum. Owing to depletion of petroleum over years, it can be anticipated that petroleum-derived products such as MI oils will also deplete future. are not only non-renewable, but they non-biodegradable, where these harmful environment cases spillage. Therefore, aim this study investigate potential mixing with natural ester (NEI) order reduce high dependency on for transformer applications. The and NEI were mixed different ratios. AC breakdown voltage test was conducted MI-NEI blends according ASTM D1816 standard. From results, found following ratios (30% + 70% 20% 80% oil) result significant improvement terms compared unused oil. flash point corrosivity levels examined.