Electrical Trees and Partial Discharges in Silicone Rubber Nanocomposites Containing Silica Nanoparticles.

Electrical treeing is one of the major breakdown mechanisms for solid dielectrics when subjected to high electric stress. It is a damaging process due to partial discharge (PD) and progresses through the stressed insulation by chemical degradation whose path resembles the form of a tree root. Numerous methods have been proposed to increase the tree resistance of the insulating materials, such as adding tree inhibitors, reinforcement, and modifying the insulating material. In overcoming this phenomenon, nanocomposites have gained broad interest as insulating materials due to their excellent ability to resist electrical treeing. Introducing nanofiller into the polymer matrix is an impressive and promising method to enhance the electrical tree endurance. In fact, this may increase the resistivity of polymer to suppress the growth of electrical trees inside the insulation medium. This article presents a study on the electrical tree performances with its associated PD and the influence of filler concentration in silicone rubber (SiR) samples filled with silicon dioxide (SiO2) as the nanoparticles for electrical treeing retardant. Previous research that used SiO2 as a filler showed lots of improvement on the breakdown test compared to the unfilled SiR, which prompted this study. The electrical tree performance of SiR nanocomposites containing SiO2 nanoparticles, however, has received limited attention. The electrical tree experiments were carried out by applying a fixed AC voltage of 12 kVrms at a power frequency of 50 Hz to unfilled SiR and SiR nanocomposites containing 1 wt%, 3 wt%, and 5 wt% SiO2 nanoparticles. The outcome parameters investigated to evaluate the electrical tree performances were tree initiation time, tree propagation time, growth rate, and tree breakdown time concerning its associated PD characteristics. This study found that the SiR nanocomposites could suppress the electrical trees better than the unfilled SiR. Moreover, increasing the filler content increased the electrical tree performances of the SiR nanocomposites. This finding suggests that the SiO2 can be exploited as a filler in SiR polymeric insulating materials for inhibition of electrical tree. [ABSTRACT FROM AUTHOR]