Transesterification Approaches to Natural Esters for Transformer Insulating Fluids: A Review

In recent years, natural esters (NEs) have become pivotal components in the transformer industry, serving as effective insulating fluids. NE’s growing market potential is attributed to its K-class insulation capability and biodegradability. However, the challenges in NE retrofilling often result in poor oxidative stability, sol and gel formation, and non-Newtonian behavior after aging. The transesterification of NEs into fatty acid methyl ester (FAME) has garnered significant attention for its potential to address these challenges. Nevertheless, the evolving theories surrounding transesterification have led to diverse perspectives on this process. Challenges arise from the precise addition of catalysts, base oils, and the selection of optimal process parameters, rendering the overall process complex and intricate. This comprehensive review aims to consolidate and present essential information on transesterification and its associated processes in a single source. By providing insights into crucial process parameters, this review facilitates a better understanding of esterification. Additionally, it delves into discussions about standardization, process parameter optimization, and the impact of these processes on dielectric responses, fostering a research-oriented perspective.