HVDC and HVAC electrical breakdown characteristics of epoxy nano composites according to the filling content of surface-modified nanosilica

In this study, the surface of nano silica was modified to improve the insulation characteristics of high voltage based heavy electric equipment. The surface-modified nanosilica was homogeneously dispersed by filling the epoxy resin with different contents (0,1,3,5,7,9phr) and Epoxy / Nano Silica Composites were prepared. The glass transition temperature was determined for the homogeneous dispersion of surface-modified nanoparticles, and for evaluation of interfacial and thermal properties. Short-term HVDC positive polarity breakdown and HVAC breakdown characteristics were evaluated as electrical insulation performance improvement. Also, for the long-term reliability evaluation, the AC electrical tree characteristic was evaluated under inequality by frequency acceleration degradation method. The glass transition temperature increased with the increase of the content of nano-silica surface-modified on the epoxy resin, and the dielectric breakdown strength increased with the filling content of HVDC insulation breakdown and decreased with HVAC. Moreover, the insulation life decreased with the increase of the filling content in the long time electric tree experiment. Copyright © The Korean Institute of Electrical Engineers