Patent ID: 7994427

Claim:
A high voltage insulation system for high-voltage direct current, comprising: a bushing including a conductor, a transformer conductor, a connection between the conductor and the transformer conductor, a conductive shielding electrode shields the connection between the bushing and the transformer conductor, a surrounding insulation system immersed in transformer oil, the surrounding insulation system comprising transformer insulation material and bushing insulation material, a cylindrical solid insulation barrier enclosing the connection between the bushing conductor and transformer conductor, and a plurality of solid insulation barriers arranged radially outwards from the shielding electrode, wherein the solid insulation barriers are fastened to the shielding electrode on an outer side of the shielding electrode, wherein the solid insulation barriers extend in an axial direction outside an axial direction of the shielding electrode and form a distance to the insulation material of the bushing and the transformer insulation material, whereby a moderate voltage drop over the solid insulation barriers is obtained, and wherein oil ducts are arranged between adjacent solid insulation barriers wherein the extent of the solid insulation barriers and cylindrical insulation barrier provides a free path between the shielding electrode at high potential a ground.