Temperature dependance of PD from electrical trees grown in silicone rubber based nanocomposites

This paper describes a set of experiments to assess temperature dependence on phase-resolved partial discharge activity during electrical tree growth in a room temperature vulcanized silicone rubber/organo-Montmorillonite (oMMT) nanocomposite material. The filler particles were prepared by treating MMT with alkylammonium before dispersing in the silicone rubber to form the silicone/organo-Montmorillonite nanocomposite. The samples were prepared with three levels of nanofiller content, 0% by wt, 1% by wt and 3% by wt in order to assess the effect of different filler concentrations on the treeing process and the corresponding PD activity under an applied 50Hz AC electrical stress. The results demonstrate that the introduction of 1% by wt of nano-filler increases the tree inception times and decreases the rate of tree growth. It was also found that the PD characteristics, particularly the mean phase angle of occurrence of the positive and negative discharge distributions, became insensitive to variations in temperature. This reflects an enhanced stability in the nanocomposite electrical properties compared with the base polymer. Tree initiation and growth were found to be suppressed in the case of the 3% by wt nanocomposite to the extent that tree growth did not occur over the duration of the test (4 hours).