Fabrication technique of permittivity graded materials (FGM) for disk-type solid insulator

For the electric field control, relaxation and optimization in a solid insulator of electric power apparatus, we have been investigating functionally graded materials (FGM) with spatial distribution of dielectric permittivity (ε_r). We have so far developed the fabrication and simulation techniques of FGM with a cylindrical shape for post-type solid insulator of gas insulated switchgears (GIS). In this paper, we extended our FGM techniques to the coaxial shape for disk-type solid insulator. We succeeded to fabricate and simulate FGM with ε_r-grading to lower permittivity (GLP-FGM) and with U-shape ε_r-distribution (U-FGM) along the radius of disk-type GIS spacer.