DC Breakdown Strength and Conduction Current of MgO/LDPE Composite Influenced by Filler Size

A nano-composite material is attracting many researchers´ attention in the field of dielectric and electrical insulation. The purpose of this study is to investigate the influence of MgO filler size on electrical properties of MgO/LDPE nanocomposite. The volume resistivity, DC breakdown strength and the impulse breakdown strength of low-density polyethylene (LDPE) containing nano-filler or micro-filler of magnesium oxide (MgO) were measured. The volume resistivity of the sample without the MgO filler increases by addition of the MgO nano-filler or the MgO micro-filler. The impulse breakdown strength and the DC breakdown strength of the sample without the MgO filler measured with McKeown type electrode increases by the addition of the MgO nano-filler but that does not increase by the addition of the MgO micro-filler. From the result, it becomes clear that the addition of the MgO nano-filler is suitable for the DC insulating material rather than that of the MgO micro-filler.