Influence of nano-titanium dioxide (TiO2) on electrical tree characteristics in silicone rubber based nanocomposite

Electrical tree is recognized as one of the pre-breakdown phenomena that occurs in high voltage insulation material. In addition, under high divergent field, the electrical tree grows rapidly and severely which may cause the breakdown of insulation to occur. In view of foregoing, nano-filler was added into the base insulating materials to enhance their properties against the growth of electrical tree. Thus in this study, nano-titanium dioxide was chosen as filler in order to improve the characteristics of silicone rubber which in turn inhibits the growth of electrical tree. The test samples were prepared in the form of leaf-like specimen. Nano-titanium dioxide was chosen as filler in order to improve the characteristics of silicone rubber. The number of partial discharge occurrence, partial discharge magnitude and breakdown time of the nanocomposites were investigated under different percentage of nano-titanium dioxide. The applied voltage and frequency were fixed at 10 kVrms AC and 50 Hz respectively. Treeing growth was recorded and partial discharge was observed at the constant applied voltage. The findings in this research showed that under high concentration of nano titanium dioxide, the treeing propagation were reduced and partial discharge number increased. The function of nano titanium dioxide as obstacle for the tree path in the silicone rubber samples was successfully tested. The results have shown that physical bonding between nano-titanium dioxide and silicone rubber matrix was improved, the tree propagation speed decreased, and this resulted in the increment of partial discharge magnitude. However, further experimentation is required to give more clarifications regarding to this finding.