Digital HVDC partial discharge testing

The measuring circuit for measuring Partial Discharges (PDs) does not differ when using AC or DC voltage. What differs is the analysis of the measured data. First, because there is no phase resolved information. Secondly, because of the much lower repetition rates. In addition, AC and DC high voltage applications tend to be quite different. With a new digital PD detector, the HVDC PD testing can be done with one apparatus instead of a number of pulse counters (existing standards set limits to the number of PDs in a PD band) as well as a deeper understanding of the PD behavior. We present our experience with this new detector.