Currently switch manufacturers have paid more and more attention to solid insulated switchgear（SIS）.The usage of solid insulated switchgear is needed more and more and also the requirement to its performance is higher and higher. In order to satisfy the reliability and safety of the product

the conductive or semi-conductive coating is sprayed on the outer surface of the insulation component

and the coating layer must be grounded so as to contactable to human body is safety. But we found that the original electric field distribution changed subversively and thus resulted in many problems for electrical performance

especially such as the gas discharge caused in the isolation break and soft connection position

after spraying metal coating on the surface of SIS to improve its reliability. On the basis of 3-D FEM simulation analysis

a reliable and feasible proposal has been made.