Interfacial E-field Regulating Insulator for DC Gas-solid Insulating System

To reduce the electric field (E-field) distortion in a gassolid insulating system, a centrifugation technique is proposed to fabricate the interfacial E-field regulating (IER) insulator. During the curing process of the liquid epoxy/SiC mixture in the mold, a centrifugal force was used to force the SiC particles to the insulator surface, forming a uniform thin surface layer of nonlinear conductivity. After fabrication, electrical evaluations, including numerical simulations and flashover tests, were conducted to verify the E-field regulating effect of the novel insulator. As the thickness of the nonlinear-conductivity layer increases, the maximum E-field in the flashover region of the novel insulator declines and converges to a stable value, but the surface conduction loss continues growing. The flashover voltages of the novel insulator are improved by ~13% and ~21% under positive and negative voltages, respectively. By applying such novel insulators, a higher reliability and compacter structure can be realized for the DC-GIL.