Pulsed x-ray induced partial discharge: Phase and time-resolved measurements

The use of short x-ray pulses (duration 50 ns) has shown to eliminate the statistical time lag by providing start electrons for the partial discharge (PD) development in a void, which makes it possible to detect very small voids at low electric field levels. In this paper a predefined measurement procedure which includes both a conventional (CONV. PD) and pulsed x-ray induced partial discharge (PXIPD) measurement, allows the comparison of the quantitative parameters and phase resolved partial discharge (PRPD) patterns of self-produced transparent epoxy samples, each containing a single void of spherical shape naturally developed during the casting process. Additionally, to study the PD mechanism by analyzing the shape of the discharge pulse a time-resolved partial discharge (TRPD) detection circuit was developed. These triggered-fast-pulse measurements allow the comparison of the shape of the first PD induced artificially by the x-ray pulse and conventionally by natural radiation. The development of the partial discharge with time is also shown and compared.