Effect of Nano-alumina on electric tree growth in SiR nanocomposites

Abstract

Nowadays, nano technology is one of the new approaches used in enhancing the strength of polymeric insulating material. This paper presents the process of electric tree growth within 30 min after tree inception (TIV) in unfilled Silicone Rubber (SiR) as well as in SiR/Alumina nanocomposites up to 3 vol.%. Once TIV occurred, fixed 8 kVrms, 50 Hz Ac supply voltage was stressed to the specimen in order to monitor the electrical tree growth process within this period of time. The result shows that the tree growth pattern appears regularly in Branch tree type during the growth process for unfilled SiR while Bush tree type can be observed more frequently by increasing nano-alumina up to 2 vol.%. However at 3 vol.%, the fastest electrical tree growth can be observed and most of the trees tend to appear in Pine Branch tree pattern due to the slight agglomeration in filler dispersion. The result shows that, up to 2 vol.% for homogenous dispersion of filler, nano alumina can act as a resistance of electrical growth but further filler increasing up to 3 vol.% lead to the worst propagation rate.