Partial discharges in solid insulators-an experimental investigation

The application of strong electric fields reaching breakdown values, on industrial dielectrics has a profound effect on their electrical properties. Partial discharges are among the parameters of primary importance, which affect the aging procedure. In this paper a measuring method is proposed which involves high sampling frequency analog/digital converters to the classical experimental set up. Focusing in a single partial discharge, the individual characteristics i.e. the energy of electrons and the emitted radiation, are reported. This was achieved as HSF A/D converters provides a considerable number of measurements of the potential profile across a measuring capacitor (or resistance) even in the sort time period of a single partial discharge. From the results it may be stated that s-type negative differential resistance and current instabilities during the prebreakdown stages of industrial insulators are presented.