PD Pattern dependence on relative humidity in twisted pairs

Partial discharge (PD) pattern recognition and interpretation is still often the key to assess the presence and the nature of defects inside electrical insulation. In the case of external PD source, as when surface partial discharges are concerned, the PD pattern can be strongly influenced by the environmental conditions. This work presents the experimental outcome of a PD measurement campaign performed on enameled wire twisted pair specimens and aimed at investigating the effect of relative humidity (RH) on the monitored PD activity.