Vegetable fluids: the reason of the new trend

In recent time the use of natural esters (NE), as well synthetic esters (SE), are growing up much faster than expected. Despite some little drawbacks (oxidation stability, viscosity) the advantages in terms of transformer life extension, reduced risk of fire, biodegradability and sustainability have resulted in esters being applied in all types of electrical equipment. Even without mention the conventional and historical application for distribution, large power transformers with no limit in terms of voltage or power have been installed in many countries, railway traction transformers and offshore wind turbine are today filled with NE or SE only, SF6 in instrument transformer is progressively replaced by NE. Focus of this paper is to understand the reason of the current market new "green" orientation. Performances like oxidation stability, gassing, water tolerance, self-extinguishing and smoke emission in case of fire.