Electrical tree in HTV silicone rubber under mechanical stress

Abstract

In the cable accessories, the electrical properties of silicone rubber (SiR) insulating materials are affected by mechanical stress, which is produced by the spring clamp device or the banding force after the expansion of SiR stress cone. in this paper, the pin-plane electrode system was employed in the experiment to investigate the electrical tree growth characteristics under the tensile and compressive stress. The results indicate that the electrical tree propagation characteristics are affected by both the tensile stress and compressive stress. As the tensile stress increasing, the length, fractal dimension (FD) and accumulated damage (AD) of electrical tree become lager, which indicates that the electrical treeing process is accelerated under higher tensile stress. However, the elelctrical tree growth process shows a converse trend under the compressive stress, which demonstrates that the electrical tree growth is retarded under higher compressive rate.