Comparative studies of the stabilities to oxidation and electrical discharge between ester fluids and transformer oils

The growing demands for improved fire safety, source material sustainability, environment friendliness, and asset life extension have driven the research and development efforts of natural/synthetic esters, less-flammable fluids. This contribution reports some investigations on commercially available ester fluids. Many comparisons are made to the quality test results of mineral oil, as this is something we are all familiar with. The stability under electrical stress and the stability to aging of the insulating fluids were investigated. The gassing performance characteristics of natural ester fluids are far superior to those of conventional mineral oil. A significant reduction in insulation aging rate was observed with synthetic ester fluids.