Electrical Tree Characteristics in Graphene/SiR Nanocomposites under Temperature Gradient

Abstract

In this paper, graphene/silicone rubber (SiR) nanocomposites with filler contents of 0.001 ∼ 0.005 wt % are prepared to improve electrical tree inhibiting ability under different temperature gradients. The electrical treeing test is performed under three temperature gradients, by controlling the temperature of high voltage and ground sides. Experimental results indicate that the SiR sample with 0.003 wt% graphene presents the best performance on electrical tree resistance. The tree length and accumulated damage are both reduced with the increase of graphene content from 0 to 0.003 wt %, but increased with the further increase of filler content from 0.003 to 0.005 wt %. The tree outline tends to be circular in neat SiR under negative temperature gradient, while is triangular under positive temperature gradient. However, the effect of temperature gradient is weakened when graphene exists. The doping of graphene leads to deeper trap sites at the interfaces between nanoplatelets and polymer matrix, which enhances electrical resistances of SiR. This research provides an effective method to suppress electrical trees of SiR for cable accessories.