Dielectric properties and creepage discharge of epoxy/silica nanocomposite in mineral oil

This paper deals with the effect of the nano filler loading in epoxy resin (EP) on creepage discharge properties of the epoxy/silica nanocomposite (EP/S-NC) in mineral oil under standard lightning impulse voltage application using needle-bar electrode arrangement. Experimental results allow to estimate discharge occurrence probability (P
_d
) at each voltage level. The relative permittivity ε'
_r
. and dielectric loss are measured at 50 Hz-5 MHz for EP/S-NC with a good dispersion of nanoparticles in the base epoxy matrix. As a result, it is found that P
_d
decreases with increasing the filler loading up to 1 wt%, and then increases. Namely, the nano filler content of 1 wt% produces the best insulation performance in terms of Pd. The relative permittivity of the composite decreases with decreasing the filler loading below 1 wt%, while further increasing nano silica filler loading results in increased ε'
_r
above 3 wt%.