A Simple Analysis on the Function of the Conductive Particles in the Insulator Voltage-Sustaining Layer for Power Devices

The function of conductive particles on the insulator for a simple case is analyzed in this paper. In a certain insulator containing conductive particles, the electric dipoles in the conductive particles are induced by the external electric field, and the polarization orientation is along the direction of electric field. Macroscopically, the insulator containing conductive particles can be equivalent to a high-permittivity (ε
_eff
) insulator. Meanwhile, the maximum electric field (E
_max
) in the insulator containing conductive particles is enhanced. The ε
_eff
and E
_max
are determined not only by the geometric shape, size, and the packing modes of conductive particles. This paper presents several packing modes of conductive particles in the insulator. Simulation results indicate that when cubic conductive particles with side length 2R are stacked in the form of cubic close packing, the ε
_eff
and the E
_max
of the insulator containing conductive particles at R/d = 0.495 (d is the distance between the centers of the mass of closet conductive particles) are increased to 67.1 times and 97.5 times, respectively, compared with the insulator without conductive particles inside.