Processing and Evaluation of Natural Esters

The main focus of this chapter is the processing of the natural ester‐based oils to be used as an insulating liquid in a transformer and other electrical apparatus. Natural esters are eco‐friendly alternatives obtained from renewable resources such as plant seeds. These natural oils are composed of triglycerides, which react with alcohol to produce fatty acid methyl ester, a form suitable for usage in power apparatus applications. This work focuses on the extraction and preparation of these natural esters from the seeds to the operational form. A brief overview of the electrical, physical, and chemical properties of the natural ester oils is given to understand how these oils perform when compared with the conventional mineral oil. The aging of the oil specimens with varying time durations has been covered and spectroscopic analysis of the oils both before and after aging is explained extensively to understand their long‐term performance. The fault detection with the help of dissolved gas analysis (DGA) is covered to ascertain how some of these oils behave when gases develop under conditions of incipient faults.