Study on the oxidative stability of palm fatty acid ester (PFAE) as an insulating oil for transformers

Today, esters obtained from plant oils are attracting attention as insulating oils from the viewpoints of renewable resources and low environment impact in the event of leakage. We have developed a palm fatty acid ester (PFAE) synthesized from palm/coconut oil for use as an environmentally friendly insulating oil. PFAE is expected to be an alternative to mineral oil because of its high fluidity and high dielectric characteristics. On the other hand, because insulating oil for transformers is used over several decades, high oxidative stability is required. In our study, we investigate oxidative stability with regard to the electro-chemical characteristics of PFAE compared to another vegetable oil. As a result, the breakdown voltage and total acid value of PFAE showed less change than the other oil. We discuss differences in the oxidation stability of PFAE and it superiority over the other vegetable oil.