Static electrification of different solid-liquid couples used in transformers for insulation

Since the middle of the 1970s the static electrification phenomenon was made responsible for several outages of forced cooled, high voltage power transformers. The forced oil flow results in electrostatic charging between the liquid and the solid insulation. Most of the research done till now in this field concerned the electrostatic charging behavior of mineral oil - cellulose insulation systems, conventionally applied in power transformers. The aim of the research activity at the Institute of High Voltage Engineering and System Management is the investigation of not so well studied solid - liquid couples. In this paper first investigations by the institute concerning static electrification of aramid in combination with different insulating liquids are shown.