Numerical Analysis of Surface Electric Field Profiles for Spacers with Continuous Grading of Permittivity

Application of Functionally Graded Material in which permittivity is graded ($epsilon$-FGM) to solid spacers used in high voltage power apparatus such as GIL etc. have been proposed by the authors in order to develop future all-solid power substation as well as to improve the surface breakdown characteristics lessened by using SF$_6$ mixture gases. In the present contribution numerically demonstrated are how the permittivity grading of both post-type and corn-type spacers mitigates the electric field around the spacer, especially along the spacer surface, which is closely related with partial discharge generation and succeeding surface breakdown