Micro-Mechanisms Driving Improvement in Cold Flow Properties of Natural Ester Insulating Oils

Natural ester insulating oil is gaining popularity as an environmentally friendly and renewable alternative to mineral insulating oil, offering enhanced fire safety. However, challenges arise from its poor fluidity and high pour point, limiting its widespread adoption in transformers in cold environments. To address this, the study explores the electrostatic potential (ESP) and van der Waals (vdW) potential of the four primary triglycerides in soybean-based natural ester insulating oils. The investigation identifies trilinolenin as a key factor influencing low-temperature fluidity. By strategically increasing the content of trilinolenin in soybean-based natural ester insulating oil, the low-temperature fluidity and cold flow properties can be improved, consequently reducing the pour point. Molecular dynamics simulations further confirm that adding 0.5 times trilinolenin to the original soybean-based natural ester insulating oil effectively lowers the pour point. This research contributes valuable insights to enhance the applicability and reliability of natural ester insulating oil transformers in low-temperature environments.