Effect of micro-sized filler loading on surface erosion of silicone rubber composite insulators

Summary

Polymeric materials such as silicone rubber (SiR) are widely used in high voltage outdoor insulating systems and it has been shown that a practical solution to improve the thermal characteristics of SiR is to add micro-sized inorganic particles. Regarding its electrical performance in long-term operation under wet and polluted environment, one of the main selection criteria is its resistance against surface tracking and erosion. In this paper, the tracking and erosion resistance of SiR filled with micron alumina trihydrate (ATH) and aluminium nitride (AlN) is compared along with thermal conductivity and thermal dissipation performance. For the experiment, test samples are prepared by dispersing micro-sized ATH and AlN fillers into room temperature vulcanizing SiR at different loadings. The dispersion process includes the traditional mechanical mixing followed by ultra-sonication. For each test sample, the inclined plane test according to IEC 60587 Standard was carried out, lasted for 4 hours with initial applied voltage of 3 kV and then increased at a rate of 0.25 kV/h. Experimental results show that with the increase in content of both AlN and ATH micro-fillers (from 0 to 30 wt%), the thermal conductivity of SiR composite increases. The lesser erosion depth and leakage current are noticed in the ATH filled composites. Thermal distribution findings indicate that heat is mainly accumulated in the discharge area and ATH dissipates it more efficiently than AlN which results in better tracking and erosion resistance.

Additional informations

Authors

SC C2, BLACKBURN

Keywords

Composite insulator, silicone rubber, micro filler, surface erosion