Tracking and surface degradation of barium titanate filled silicone rubber nanocomposites

Abstract

Silicone rubber (SR) based composite insulators are being increasingly used in HV transmission lines because of their superior performance in polluted environments. The surface hydrophobicity of SR based insulators makes them ideal for use as outdoor insulation especially in polluted environments. Research in nanodielectrics in the last decade has shown that addition of nanosized fillers into bulk polymers often improve their electrical and non-electrical properties significantly. In this work, we study the effect of incorporating barium titanate nanofillers into room temperature vulcanized silicone rubber (RTVSR). Nano-sized barium titanate (BaTiO3) particles are used as fillers in the RTVSR matrix with volume fractions of 0.5%, 1%, and 2%. While preparing samples, mechanical mixing and ultrasonic mixing are used for reducing the agglomeration of nano fillers. Barium titanate fillers are expected to increase the permittivity of the composite, thus helping in electric field stress control. One of the most important issues in outdoor insulation is tracking. Tracking on the surface of the insulator leads to degradation, and even complete failure of the insulator. In this work, we study the effect of incorporation of nano-fillers on propensity of RTVSR to tracking and associated degradation. Inclined Plane Test (IPT) for erosion as per the IEC60587 is performed. Additionally, surface degradation tests are performed to estimate how the addition of nano fillers increases the resistance to degradation due to surface discharges. It is seen that SR filled with nanosized barium titanate fillers show better resistance to tracking as well as surface degradation.