Effect of ATH filler content on the performance of silicone rubber by inclined plane tracking and erosion test method

Contamination flashover is a major concern affecting the reliability of power systems. Many utilities have switched over from porcelain and glass insulators to Silicon Rubber (SIR) based polymeric insulators to combat contamination problem. By and large, Aluminum Tri-hydrate (ATH) is used as filler material to improve the tracking and erosion property. The evaluation as per IEC 60587 does not simulate the UV radiation, any particular type of pollutant deposited on the insulator surface and the conductivity of the contaminant more likely to damage the polymeric insulator surface. In the present work, tracking and erosion of silicon rubber material with different proportions of ATH filler content included in its nano form is evaluated. In addition to experimental variables in the IEC 60587 test method site specific variables like UV radiations, hydro carbon pollution (present on the insulator surface due to presence of brick kilns in India) and low severity fog conditions are introduced to the standard test method. The surface resistance and hard ness measurements as well as X -ray diffraction analysis are also made to determine the extent of degradation of the insulator material surface resulted during tracking and erosion test. The study revealed that, the tracking and erosion performance of SIR depends on the proportion of ATH filler and it is found that ATH and silicon in equal parts by weight is the best combination. It is also noticed that incorporating nano ATH filler further improves the performance.