Molded tap changer assemblies and methods for dry-type transformers

Patent metadata

Field	Value
Publication number	US-11049647-B2
Application number	US-201817046372-A
Country	US
Kind code	B2
Filing date	Apr 23, 2018
Priority date	Apr 23, 2018
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A tap changer assembly of a dry-type transformer. The tap changer assembly includes a first molding including multiple taps, a semi-conductive coating applied to the first molding, a conductive shield provided overtop some of the semi-conductive coating, a grounding member comprising a ring of bosses interconnected by a grounding conductor connected to the conductive shield, a second molding applied over at least a portion of the conductive shield and the grounding conductor, the second molding forming a molded sealing surface, a conductive cover coupled to the ring of bosses; and a sealing member sealing a space between the molded sealing surface and the conductive cover. Dry-type transformers and methods of forming a tap changer assembly of a dry-type transformer are provided, as are numerous other aspects.

First claim

What is claimed is:

1. A tap changer assembly, comprising:
a first molding including multiple taps;
a semi-conductive coating applied to an outer surface of the first molding;
a conductive shield provided in contact with the semi-conductive coating;
a grounding member comprising a ring of bosses interconnected by a grounding conductor;
a second molding applied over at least a portion of the conductive shield and the grounding conductor, the second molding including a molded sealing surface;
a conductive cover coupled to the ring of bosses; and
a sealing member sealing between the molded sealing surface and the conductive cover.

2. The tap changer assembly of claim 1 , wherein the grounding member comprises a grounding interconnector coupled to the grounding conductor and configured to attach to the conductive shield.

3. The tap changer assembly of claim 1 , wherein the grounding conductor comprises a metal wire.

4. The tap changer assembly of claim 3 , wherein the metal wire is connected to a bottom of each of the bosses.

5. The tap changer assembly of claim 4 , wherein the metal wire is connected to each of the bosses by braising.

6. The tap changer assembly of claim 4 , wherein the metal wire comprises a broken ring.

7. The tap changer assembly of claim 1 , wherein the conductive cover is coupled to the ring of bosses by a corresponding ring of fasteners.

8. The tap changer assembly of claim 1 , wherein each of the bosses comprise a top portion having a circular shape in transverse cross section, and a bottom portion having a hexagonal shape in transverse cross section.

9. The tap changer assembly of claim 1 , wherein the grounding member comprises a grounding interconnector wrapped about the grounding conductor and attach to the conductive shield by a fastener.

10. The tap changer assembly of claim 9 , wherein the fastener comprises a rivet.

11. The tap changer assembly of claim 1 , wherein the semi-conductive coating has an electrical resistivity at room temperature of greater than or equal to 500 Ohm/□ and lower than or equal to 20,000 Ohm/measured per DIN EN 62631-3-2.

12. The tap changer assembly of claim 1 , wherein the conductive shield has an electrical conductivity of greater than 1.0×10 3 S/m.

13. The tap changer assembly of claim 1 , wherein the molded sealing surface comprises an O-ring groove.

14. The tap changer assembly of claim 1 wherein the grounding member comprises the ring of bosses interconnected by the grounding conductor, and the second molding applied over at least a shield portion of the conductive shield and the grounding conductor comprises a separately-molded member.

15. The tap changer assembly of claim 14 comprising a third molding applied over at least a molding portion of the second molding and at least a molding portion of the first molding.

16. The tap changer assembly of claim 14 wherein the separately-molded member is received over a pilot formed on the first molding.

17. The tap changer assembly of claim 14 wherein the separately-molded member is molded or cast as a separate piece and is mechanically joined to the first molding.

18. The tap changer assembly of claim 17 wherein the separately-molded member comprises a portion of the conductive shield that is unmolded.

19. A dry-type transformer, comprising:
a coil assembly having an inner coil, an outer coil, and a tap changer assembly having multiple taps configured to allow voltage adjustments across the outer coil, the tap changer assembly, comprising:
a first molding including the multiple taps;
a semi-conductive coating applied to an outer surface of the first molding;
a conductive shield provided in contact with the semi-conductive coating;
a grounding member comprising a ring of bosses interconnected by a grounding conductor;
a second molding applied over at least a portion of the conductive shield and the grounding conductor, the second molding including a molded sealing surface;
a conductive cover coupled to the ring of bosses; and
a sealing member sealing between the molded sealing surface and the conductive cover.

Assignees

• Siemens Ag
• Hainan Jinpan Smart Tech Co Ltd
• Siemens Energy Global Gmbh & Co Kg

Inventors

• Navarro Martin Alsina
• Moreno Andre Luiz
• Wang Yaoqiang
• Zhang Yuqian
• Lu Xiaofeng

Classifications

• H01F27/363

  made of electrically conductive material · CPC title

• H01F2027/328

  Dry-type transformer with encapsulated foil winding, e.g. windings coaxially arranged on core legs with spacers for cooling and with three phases · CPC title

• H01F29/02 Primary

  with tappings on coil or winding; with provision for rearrangement or interconnection of windings · CPC title

• H01F29/00

  Variable transformers or inductances not covered by group H01F21/00 {(tap change devices H01H9/0005)} · CPC title

• H01F29/025 Primary

  Constructional details of transformers or reactors with tapping on coil or windings · CPC title