The electrostatic charging tendency of some environmentally friendly insulating fluids

The growing demands for improved fire safety, source material sustainability, environment friendliness, and asset life extension have driven the research and development efforts on natural/synthetic esters, less-flammable fluids. High flash point (HFP) liquids also known as “less flammable” liquids (natural/synthetic ester and silicon fluids) were then introduced. The aim of this contribution is to report some investigations onto the Electrostatic Charging Tendency (ECT) of some commercially available ester fluids. Comparison is made with mineral oil, as this is a fluid we are familiar with. The investigations were performed using a spinning disk system designed in our laboratory, in which the disk is coated on both sides with different cellulose paper. Recall that this system was adopted by CIGRE for international comparative measurements of both insulating liquid and solid transformer materials. The obtained results indicate that the electrification current vary according to fluids motion. This variation is very important at higher speeds (above 600 rpm). In most tests carried out, esters seem to generate more charges than mineral oil.