Tailoring charge transport in epoxy based composite under temperature gradient using K₂Ti₆O₁₃ and asbestine whiskers

The solid-gas interface flashover performance of insulators under dc is influenced to a considerable extent by the residual charge effect. The investigation of the charge origin and charge transport in dielectric materials is a significant topic. In this work, the Al₂O₃-filled epoxy resin composite was manufactured as the basic dielectric composite. To investigate the charge transport behavior and restrain the charge injection under the temperature gradient, asbestine and K₂Ti₆O₁₃ whiskers were doped into the basic matrix and post type model insulators were prepared. Experimental results demonstrate that the introduction of K₂Ti₆O₁₃ whiskers can effectively restrain heat propagation due to its excellent thermal barrier property, which can restrain the charge transport under temperature gradient to some extent. The charge injection level increases for insulator doped with asbestine whisker, which is due to the introduction of large amounts of shallow traps with trap level density ranging from 0.75–0.91 eV. This work is helpful to understand DC charge transport behavior under temperature gradient and provides important significance in design of a suitable insulator inside HVDC GIL. (paper)