Gas-insulated electrical equipment comprising at least one grading shield for ensuring convection exchange

A gas-insulated substation having an enclosure filled with dielectric gas under pressure, comprising:—at least one electrical conductor designed to be live that is of longitudinal axis and placed inside the enclosure, and—at least one grading shield surrounding at least one longitudinal fraction of said electrical conductor, said grading shield comprising a hollow electrically conductive body of longitudinal axis that is substantially coaxial with the longitudinal axis of the enclosure, said hollow electrically conductive body comprising at least one annular depression in its outer surface and at least one orifice passing through the hollow electrically conductive body in order to ensure that the dielectric gas flows between an inside zone and a zone that is outside the grading shield, said orifice being made in a bottom of said annular depression, wherein the annular depression comprises a concave profile that opens in a direction away from the longitudinal axis of the enclosure, wherein the grading shield comprises two annular bosses, each presenting a radius of curvature, the two annular bosses being disposed axially on either side of the annular depression, one side of the annular depression being formed by the side of one of the two annular bosses and another said of the annular depression begin formed by the side of the other of the two annular bosses.