Mechanism of Insulation Lifetime Extension of Epoxy/TiO2 Nanocomposites with Enclosed Void

Polymer nanocomposites have attracted attention for various superior insulation performances. However, the effect of nanocomposites on the insulation lifetime with an enclosed void defect is unclear. Also, the insulation lifetime extension mechanism has rarely been reported. This paper experimentally investigates the lifetime extension mechanism of epoxy/TiO2 nanocomposites with the void defect. Centrifugation and dilution procedures are used to control the dispersion state of TiO2 nanofillers. Time evolutions of partial discharge (PD) current are also recorded to investigate the insulation degradation procedure. Consequently, it is clarified that the lifetime becomes longer with increasing the maximum agglomerate size of the TiO2 nanofillers. Results of the PD current monitoring suggest that the lifetime extension of the nanocomposite is achieved due to delaying the electrical tree propagation in the sample.