Benefits of Research on Solid Insulation Ageing in Ester Liquids

Ester liquids have become established as an alternative option to mineral oil dielectric liquids in transformers, and their use continues to grow particularly where increased fire safety or environmental risk reduction is required. However, another often undervalued benefit is the ability of esters to operate at higher temperatures and extend the life of the solid insulation in service. This paper will present a summary of research undertaken on solids insulation with ester liquids and the potential benefits to transformer design and operation.