HIGH VOLTAGE INSULATION SYSTEM AND A METHOD OF MANUFACTURING SAME

• US 20090108973A1
• Filed: 03/24/2007
• Published: 04/30/2009
• Est. Priority Date: 03/24/2006
• Status: Active Grant

• Current Assignee: Hitachi Energy Limited
• Original Assignee: ABB Technology Limited (ABB Ltd.)
• Inventors: Berglund, Mats, Svensson, Lars-Ake, Forsberg, Erik, Jorendal, Gunnar, Polander, Tony, Vennerberg, Lars-Erik
• Granted Patent: US 7,994,427 B2
• Time in Patent Office: Days
• US Class Current: 336/94
• CPC Class Codes: H01F 27/04 Leading of conductors or axles through casings, e.g. for tap-changing arrangements
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/363 made of electrically conductive material
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

A high voltage insulation system for high-voltage direct current including a bushing, a conductor, a transformer conductor, and a connection between the conductor and the transformer conductor. A conductive shielding electrode shields the connection between the bushing and transformer. A surrounding insulation system is immersed in transformer oil. The surrounding insulation system includes transformer insulation material and bushing insulation material. A cylindrical solid insulation barrier encloses the connection between the bushing conductor and transformer conductor. At least one solid insulation barrier is fastened on the outer side of the shielding electrode. The at least one solid insulation barrier extends in an axial direction outside the axial direction of the shielding electrode and forms a distance to the insulation material of the bushing and the insulation material of the transformer, whereby a moderate voltage drop over the solid insulation barrier is obtained.

Claims

1. A high voltage insulation system for high-voltage direct current, comprising:

a bushing,

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 transformer,

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,

at least one solid insulation barrier fastened on the outer side of the shielding electrode, wherein the at least one solid insulation barrier extends in an axial direction outside the axial direction of the shielding electrode and forms a distance to the insulation material of the bushing and the insulation material of the transformer, whereby a moderate voltage drop over the solid insulation barrier is obtained.

2. The high voltage insulation system according to claim 1, wherein the solid insulation barrier is symmetrical.

3. The high voltage insulation system according to claim 1, wherein a number of solid insulation barriers is between 2 and 4, forming oil ducts between adjacent barriers.

4. The high voltage insulation system according to claim 3, wherein a distance between adjacent solid insulation barriers is between 2 mm and 30 mm.

5. The high voltage insulation system according to claim 1, wherein a distance to the insulation material of the bushing and the insulation material of the transformer, respectively, is between 30 mm and 200 mm.

6. The high voltage insulation system according to claim 1, wherein the insulation system is designed for AC/DC voltages over 500 kV.

7. A method for manufacture a high voltage insulation system, the method comprising:

manufacturing a transformer with transformer insulation in a first process;

manufacturing a shielding electrode with a solid insulation barrier in a second process;

manufacturing a solid insulation barrier in a third process;

manufacturing a bushing in a fourth process;

wherein each process is made independently of each other, and wherein the components are assembled on site.