Electronic International Standard Serial Number (EISSN)
Due to the global trend in the industry to work towards sustainability and clean energy, utilities and transformermanufacturers focus on the design of environmentally friendly devices. In this context, the use of natural estersas transformer's liquid insulation is becoming an habitual practice in distribution transformers. Thesefluidsmake possible the operation of transformers with lowerfire risk, what is important for certain applications.Additionally natural esters are biodegradable and their application minimizes the risk of soil contamination incase offluid's leak. One of the differential characteristics of esterfluids is that they have higher affinity formoisture than mineral oils, absorbing masses of water up to ten times greater than conventional insulatingfluidsunder similar working conditions. This fact changes the water distribution between the solid and liquid in-sulation that is typically found in mineral-oilfilled transformers. Moisture content in insulating materials re-mains as one of the most important parameters determining the life cycle of transformers, hence the importanceof fully understanding its behaviour.