A methodological evaluation on discharge phenomena at different temperatures in internal gaseous interfaces inside filled and unfilled epoxy resins used in HV components

The authors report an experimental investigation carried out to obtain information on epoxy material performance under partial discharge (PD) activity for different temperature conditions. Some observations about the effect of filler mineral charges on the electrical behavior of epoxy resins are also reported. It is noted that PD activity and temperature play an important role in the life of the insulating materials, reducing noticeably the reliability of HV (high-voltage) systems. The use of a multichannel analysis allows a more detailed diagnosis of PD activity in the insulating materials. From 20 to 80°C, it has been noted that the PDAD (PD amplitude distribution) shape changes and a number of the PDs of smaller amplitude increase in such a way as to produce a higher total charge transferred to the dielectric material. The increase of the total charge transferred to the dielectric materials due to the higher temperature and the voltage leads to a faster degradation of the material, reducing the useful life of the system