A simple detector and analyser of partial discharges

A simple low-cost partial discharge (PD) detector and analyser for insulation testing has been built based on an analogue-to-digital converter and a PC/AT microcomputer. This features a user-friendly program enabling the display of the discharges in the conventional elliptical format with the accumulated information from up to 1000 cycles, as well as in histogram form where either the number of pulses, or the average charge per pulse, are plotted with respect to phase angle. In addition, shape parameters relating to these histograms can be calculated and used to compare the different types of partial discharge and hence, by an expert system approach, attempt to classify unknown PDs