A Statistical Approach to Assess the Filler Dispersion of Silicone Rubber Composites for HV Outdoor Insulators

This paper investigates the use of a statistical analysis for assessing the filler dispersion in silicone rubber composites used for high voltage outdoor insulation applications. The study particularly examines the use of the Median Absolute Deviation as a robust measure to evaluate the variability, and thus repeatability, of thermogravimetric analysis test outcomes for different silicone rubber composites at different temperature rise rates. Different Alumina-trihydrate filled silicone rubber composites are examined in the study. The results suggest a correlation between the Median Absolute Deviation and the degree of filler dispersion observed under Scanning Electron Microscopy. This correlation in outcomes is particularly evident at 25 degrees C/min. The composites are further tested using the dry-arc resistance test as per ASTM D495. The variability in the erosion resistance outcomes of the dry-arc resistance test correlate with the Median Absolute Deviation outcomes. These outcomes collectively suggest the potential of the proposed statistical approach as a quick assessment tool to supplement microscopic imaging towards understanding the effect of the degree of filler dispersion on the erosion resistance of silicone rubber for use in high voltage outdoor insulation applications.