High voltage bushing

A high voltage bushing comprising:

• a high voltage conductor provided in a gas filled hollow insulator housing;
• a voltage grading shield comprising a cylindrical metal part provided in the insulator housing, surrounding and extending along the high voltage conductor, and
• a layer having a resistivity in a range of 108-1014 Ωm provided only on a surface of lengthwise end portions of the metal part, wherein the layer has a thickness in a range of 10-1000 μm, the layer permitting slow and controlled partial discharge of particles hitting a surface of the layer, wherein the layer comprises a ceramic material.

A high voltage bushing comprising:

• a high voltage conductor provided in a gas filled hollow insulator housing;
• a voltage grading shield comprising a cylindrical metal part provided in the insulator housing, surrounding and extending along the high voltage conductor, and
• a layer having a resistivity in a range of 108-1014 Ωm provided only on a surface of lengthwise end portions of the metal part, wherein the layer has a thickness in a range of 10-1000 μm, the layer permitting slow and controlled partial discharge of particles hitting a surface of the layer, wherein the layer comprises a polymeric base material that is any of epoxy, polyurethane, and Teflon.

A high voltage device, comprising:

• a high voltage bushing comprising a high voltage conductor provided in a gas filled hollow insulator housing, a cylindrical metal part provided in the insulator housing, surrounding and extending along the high voltage conductor, a layer having a resistivity in a range of 108-1014 Ωm provided only on a surface of lengthwise end portions of the metal part, wherein the layer has a thickness in a range of 10-1000 μm, the layer permitting slow and controlled partial discharge of particles hitting a surface of the layer, wherein the layer comprises aluminum oxide.

A high voltage device, comprising:

• a high voltage bushing comprising a high voltage conductor provided in a gas filled hollow insulator housing, a cylindrical metal part provided in the insulator housing, surrounding and extending along the high voltage conductor, a layer having a resistivity in a range of 108-1014 Ωm provided only on a surface of lengthwise end portions of the metal part, wherein the layer has a thickness in a range of 10-1000 μm, the layer permitting slow and controlled partial discharge of particles hitting a surface of the layer, wherein the layer comprises a ceramic material.

A high voltage device, comprising:

• a high voltage bushing comprising a high voltage conductor provided in a gas filled hollow insulator housing, a cylindrical metal part provided in the insulator housing, surrounding and extending along the high voltage conductor, a layer having a resistivity in a range of 108-1014 Ωm provided only on a surface of lengthwise end portions of the metal part, wherein the layer has a thickness in a range of 10-1000 μm, the layer permitting slow and controlled partial discharge of particles hitting a surface of the layer, wherein the layer comprises a polymeric base material that is any of epoxy, polyurethane, and Teflon.