Effect of filler concentration on the breakdown strength of epoxy nanocomposites

Abstract

Recent trends in the field of high voltage engineering attracts attention over the development of advanced electrical insulation systems. Electrical treeing due to highly divergent electric stress is one of the major threats to the electrical insulation. Once a treeing channel is incepted, it will lead to the propagation of electrical trees followed by insulation failure and electrical breakdown. Inclusion of nano-fillers in the base polymer(Epoxy resin) is found to resist the propagation of trees and improves the breakdown strength. This work attempts to study the effect of nano-fillers such as TiO2, ZnO, MgO with various filler concentrations for one gap distance. Test samples are made with needle plane electrode configuration to express the real time highly divergent electric field stress experienced by the cables. Neat epoxy samples were used as reference. High voltage AC at power frequency is the waveform used for the tests. The results show that Titanium oxide nano-composites exhibits higher breakdown strength than zinc oxide and Magnesium oxide nano-composites at 2 wt. % concentration. Further analysis of the results exhibits that 2 wt. % nano-fillers enhances while 1 wt. % worsens the electrical treeing resistance than neat epoxy.