PD Detection Under Impulse Voltage

The detection of partial discharge (PD) under short risetime voltage impulses is a rapidly developing field. Hundreds of technical papers are being written each year on this subject with many improvements in PD measurement technology. One of the first papers on voltage impulses leading to insulation failure of low‐voltage motors was written by Persson. He described turn insulation failures leading to stator winding failure in 600 V motors in pulp and paper mills. Subsequently, it was discovered that the failures were likely due to gradual aging of the insulation by PD. This chapter describes how short risetime voltage impulses may lead to premature insulation failure. IEC 61934 describes the procedures to determine the sensitivity of the PD measuring system, and the amount of interference that occurs, with the latter almost always being determined by the residual interference from the surge tester or voltage source, pulse width modulated converters.