Gel impregnated bushing

Patent metadata

Field	Value
Publication number	US-11488741-B2
Application number	US-201916977591-A
Country	US
Kind code	B2
Filing date	Mar 14, 2019
Priority date	Mar 19, 2018
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

The present disclosure relates to a high-voltage (HV) bushing comprising a condenser core configured for surrounding a HV electrical conductor. The condenser core comprises an insulation material comprising wound layers of a permeable solid material impregnated with a thermo-reversible gel. The gel comprises an oil and a thickener, the oil comprising iso-paraffinic oil in an amount within the range of 0.1-100 wt % of the oil and the thickener comprising at least one copolymer in an amount within the range of 0.1-10 wt % of the gel.

First claim

The invention claimed is:

1. A high-voltage (HV) bushing comprising:
a condenser core configured for surrounding a HV electrical conductor, the condenser core comprising an insulation material comprising wound layers of a permeable solid material impregnated with a thermo-reversible gel, the thermo-reversible gel comprising an oil and a thickener, the oil comprising iso-paraffinic oil in an amount within the range of 0.1-100 wt % of the oil, and the thickener comprising at least one styrenic copolymer in an amount within the range of 0.1-10 wt % of the thermo-reversible gel, the at least one styrenic copolymer comprising polystyrene-b-poly(ethylene-ethylene/propylene)-b-polystyrene, polystyrene-b-poly (ethylene/butylene)-b-polystyrene and polystyrene-b-poly(ethylene/propylene),
a liquid form of the thermo-reversible gel having a viscosity below 1 Pa·s, and
a solid form of the thermo-reversible gel having a viscosity of at least 1 Pa·s at 105° C.

2. The bushing of claim 1 , wherein the oil comprises iso-paraffinic oil in an amount within the range of 50-100 wt % of the oil.

3. The bushing of claim 1 , wherein the at least one styrenic copolymer is present in an amount of at least 1 wt % of the thermo-reversible gel.

4. The bushing of claim 1 , wherein the at least one styrenic copolymer has an average molecular weight of at least 200 kg/mole.

5. The bushing of claim 1 , wherein the polystyrene-b-poly(ethylene-ethylene/propylene) -b-polystyrene and polystyrene-b-poly(ethylene/butylene)-b-polystyrene are in an amount of at least 0.1 wt % of the thermo-reversible gel.

6. The bushing of claim 1 , wherein the polystyrene-b-poly (ethylene/propylene) in an amount of at least 0.1 wt % of the gel.

7. The bushing of claim 1 , wherein the oil comprises a mineral oil in an amount of a range of 10-50 wt % of the oil, blended with the iso-paraffinic oil.

8. The bushing of claim 1 , wherein the oil comprises the iso-paraffinic oil in an amount of a range of 60-80 wt % of the oil.

9. The bushing of claim 1 , wherein the permeable solid material comprises a cellulose-based material, an aramid paper, or a combination thereof.

10. A method of preparing a condenser core for a high-voltage (HV) bushing, the method comprising:
winding a web of a permeable solid material around a longitudinal passage for a HV electrical conductor;
mixing an oil with a thickener to form a thermo-reversible gel;
heating the thermo-reversible gel to a first temperature at which the thermo-reversible gel has a viscosity associated with a liquid form of the thermo-reversible gel below 1 Pa·s;
impregnating the wound permeable solid material with the thermo-reversible gel at said first temperature to form an insulation material comprising wound layers of the permeable solid material impregnated with the thermo-reversible gel; and
cooling the insulation material to a second temperature that is lower than 105° C. at which the thermo-reversible gel has a viscosity associated with a solid form of the thermo-reversible gel of at least 1 Pa·s to form the condenser core,
the oil comprising iso-paraffinic oil in an amount within the range of 0.1-100 wt % of the oil and the thickener comprising at least one styrenic copolymer in an amount within the range of 0.1-10 wt % of the thermo-reversible gel, the styrenic copolymer comprising:
a tri-block copolymer comprising at least one of polystyrene-b-poly(ethylene-ethylene/propylene) -b-polystyrene and polystyrene-b-poly(ethylene/butylene)-b-polystyrene; and a di-block copolymer comprising polystyrene-b-poly(ethylene/propylene).

11. The method according to claim 10 , wherein heating the thermo-reversible gel to the first temperature comprises heating the thermo-reversible gel to at least a first temperature at which the thermo-reversible gel has a viscosity at or below 0.1 Pa·s.

12. The method according to claim 10 , wherein cooling the insulation material to the second temperature comprises cooling the insulation material to the second temperature at which the thermo-reversible gel has a viscosity at or above 5 Pa·s.

13. The method according to claim 10 , wherein the first temperature is a temperature above a transition temperature of the thermo-reversible gel, wherein the second temperature is a temperature below the transition temperature, wherein the transition temperature is within a temperature range of 80° C. to 105° C.

14. The method according to claim 10 , wherein heating the gel to the first temperature comprises heating the thermo-reversible gel to at least a first temperature at which the thermo-reversible gel has a viscosity at or below 0.01 Pa·s.

15. The method according to claim 10 , wherein cooling the insulation material to the second temperature comprises cooling the insulation material to the second temperature at which the thermo-reversible gel has a viscosity of at least 100 Pa·s.

16. A high-voltage (HV) bushing comprising:
a condenser core configured for surrounding a HV electrical conductor, the condenser core comprising an insulation material comprising wound layers of a permeable solid material impregnated with a thermo-reversible gel, the thermo-reversible gel comprising an oil and a thickener, the oil comprising iso-paraffinic oil in an amount within the range of 0.1-100 wt % of the oil, and the thickener comprising at least one styrenic copolymer in an amount within the range of 0.1-10 wt % of the thermo-reversible gel, the at least one styrenic copolymer comprising polystyrene-b-poly(ethylene/butylene)-b-polystyrene and polystyrene-b-poly(ethylene/propylene),
a liquid form of the thermo-reversible gel having a viscosity below 1 Pa·s, and
a solid form of the thermo-reversible gel having a viscosity of at least 1 Pa·s at 105° C.

Assignees

• Hitachi Energy Switzerland Ag

Inventors

• Liu Rongsheng
• Brosig Gerhard
• Singha Santanu
• Cho Sung-Woo
• Nyberg Johan

Classifications

• H01B3/442

  from aromatic vinyl compounds · CPC title

• H01B3/22 Primary

  hydrocarbons · CPC title

• H01B17/28

  Capacitor type · CPC title

• H01B19/02

  Drying; Impregnating · CPC title

• C08L2203/202

  use in electrical wires or wirecoating · CPC title