Experimental Investigation of Nano Al2O3 Filled Silicone Rubber Specimen Used in Outdoor Insulation

Composite insulators are popular choice in contemporary power industry due to their numerous advantages. When these insulators are subject to various stresses, their performance gets affected due to the material degradation. One of the methods to improve the material property is to incorporate inorganic nanofillers. In this work, aluminum oxide nanofillers, synthesized in the laboratory using a solution combustion process were used and studied. The nano range was ascertained with X-ray diffraction. Those fillers were mixed in the silicone rubber specimens in 0, 1, 3, and 5 wt % concentrations. They were more rapidly aged under UV radiation, temperature, humidity and electric stresses. Dry and wet flashover tests were carried out on both virgin and aged samples, and the results showed that the concentration of 3 wt % offered a better breakdown voltage. Fourier transform infrared spectroscopy revealed percentage variations in the properties of the aged specimens, the aging resistance, degradation resistance, hydrophobicity, oxidation resistance, and erosion resistance were significantly better in 3 wt % Al₂O₃ filled samples. Scanning electron microscopy with energy dispersive X-ray spectroscopy images showed that at 3 wt % concentration there was a fairly uniform distribution of nanofillers in the silicone base and there was the least ingress of water at same weight percentage of specimens. Their improvements in the insulation property is primarily attributed to the fair distribution of nano Al₂O₃ fillers into the silicone base, a good Si–CH₃ bond structure, a low carbon cross linking and good percolation, which makes them the best candidates for outdoor insulation of power systems.