The Effect of Micro-Eggshells and Aluminium Hydroxide on Tracking Resistance of Silicone Rubber Composite

Abstract

Break down due to surface tracking is one of the critical insulation failures, especially in the polymeric insulation. It has made worse the reliability of the power transmission system. This present work attempts to solve the problem by observing the effect on tracking resistance of adding micro-eggshells and aluminum hydroxide into the silicone rubber. In order to fabricate the composite specimen, red eggshells (63 to 74 μm), aluminum hydroxide, and RTV silicone rubber were procured. The constant voltage test method, according to the IEC-60587 standard, was used to evaluate the tracking resistance; each specimen was applied by 4.5 kV for 1 hour, and the tracking length was declared as the inverse of tracking resistance. Besides, the rule of mixtures was employed to estimate the thermal conductivity. The results show that the tracking resistance of the composite specimens was overall higher as compare to the pure rubber. Moreover, It was found that tracking resistance and thermal conductivity decreased when the eggshells increased. It was described that the rise of thermal accumulation on the insulator surface in the hybrid composite caused by lower thermal conductivity. Therefore, it could be concluded that the mixing of micro-eggshells and aluminum hydroxide should not be used as fillers for suppressing the tracking failures.