The influence of temperature on partial discharge and breakdown behavior in model gas transformer windings

New concepts for a gas-insulated power transformer include a very compact winding construction, comprised of sheet aluminum conductor insulated with polymer film and impregnated with compressed SF6 gas. 60 Hz partial discharge and breakdown studies on models built with this construction have been made at 25, 100, and 125°C. A comparison has been made between models constructed with Mylar film, the material of choice to date, and with Kapton film, a backup material. For both materials, the measured performance at elevated temperature was found to be equal to or better than that at 25°C. A very similar performance was exhibited by the two polymer films.