Lifetime characterization of partial discharge properties of insulation material exposed to voltage pulse stress

The development of new technologies in the field of power electronics implies higher switching frequencies. Such frequencies are associated with higher transient voltages. Higher voltages mean stress on the insulation material. As result of this increased load, partial discharge (PD) probability can be increased, which may push the insulation material to its limits. Therefore, it is of high importance to recognize PDs. It is already known that PDs occur not only on the rising edge, but also in the steady state of a voltage pulse. However, double PDs may occur, too. Using a special test arrangement, it is possible to detect also weak PD activity, to localize the time instant and to determine changes in voltage and current. These changes are characterized e.g. by a sudden drop in pulse voltage.