Cable fitting for HVDC cables

Patent metadata

Field	Value
Publication number	US-11043797-B2
Application number	US-201816625088-A
Country	US
Kind code	B2
Filing date	Jun 22, 2018
Priority date	Jun 23, 2017
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A cable fitting for cables that can be used for high-voltage direct-current (HVDC) energy transmission, the cable fitting having an electrically insulating layer. A process for the production of an electrically insulating layer of such a cable fitting, and also the use thereof.

First claim

The invention claimed is:

1. A cable fitting for HVDC cables, comprising a molding which has multilayer structure and which has an electrically insulating layer that comprises an elastomer and that comprises a field-controlling particulate filler, wherein the field-controlling particulate filler is metal-oxide-containing core-shell particles, the core of the core-shell particles consists of a dielectric material and the shell comprises at least one electrically conductive or electrically semiconductive metal oxide.

2. The cable fitting according to claim 1 , that is a cable sleeve, a cable end seal, a cable plug or a cable bushing.

3. The cable fitting according to claim 1 , wherein the elastomer is a silicone rubber.

4. The cable fitting according to claim 3 , wherein the silicone rubber is a RTV2 silicone rubber, a HTV silicone rubber or a LSR silicone rubber.

5. The cable fitting according to claim 1 , having a density of the core-shell particles of <5 g/cm 3 .

6. The cable fitting according to claim 1 , wherein the electrically conductive or electrically semiconductive metal oxide is a doped metal oxide, a metal suboxide or an oxygen-deficient metal oxide.

7. The cable fitting according to claim 6 , wherein the metal oxide has been doped with one or more of the elements antimony, indium, tungsten, molybdenum, chromium, cobalt, manganese, iron, cadmium, gallium, germanium, tin, vanadium, niobium, tantalum, cerium, scandium, lanthanum, yttrium, bismuth, titanium, copper, calcium, strontium, barium, aluminum, arsenic, phosphorus, nitrogen, boron, fluorine or chlorine.

8. The cable fitting according to claim 1 , wherein the metal oxide is an oxide, mixed oxide or oxide mixture of zinc, tin, germanium, titanium, gallium, indium, antimony, silicon, tungsten, molybdenum, lead, cadmium, calcium, strontium, barium, copper or rhenium.

9. The cable fitting according to claim 1 , wherein the electrically insulating layer comprises a quantity of from 0.1 to 25%, based on the volume of the electrically insulating layer, of the field-controlling particulate filler.

10. The cable fitting according to claim 1 , wherein the volume resistivity of the electrically insulating layer is in the range from 10 8 to 10 13 ohm*cm.

11. A process for the production of an electrically insulating layer of a cable fitting according to claim 1 , comprising
homogeneously mixing with one another an unhardened elastomer-precursor composition, a crosslinking agent and a field-controlling particulate filler which comprises metal-oxide-containing core-shell particles, the core of the core-shell particles consisting of a dielectric material and the shell comprising at least one electrically conductive or electrically semiconductive metal oxide, and also optionally further additives, to give an insulation-layer-precursor composition,
introducing the insulation-layer-precursor composition into a hollow body which has a cavity with an exterior shape corresponding to the shape of the electrically insulating layer of a cable fitting, and
hardening the insulation-layer-precursor composition in a crosslinking manner by passage of time or introduction of heat and/or of high-energy radiation, and removing the resultant insulation layer from the hollow body.

12. The process according to claim 11 , wherein the insulation-layer-precursor composition is introduced into the hollow body by means of an injection molding process.

13. The process according to claim 11 , wherein the unhardened elastomer-precursor composition is a RTV2 silicone composition, a HTV silicone composition or a LSR silicone composition.

14. The process according to claim 11 , wherein, based on the volume of the insulation-layer-precursor composition, the quantity present therein of the field-controlling particulate filler is 0.1 to 25%.

15. The process according to claim 11 , wherein the density of the field-controlling particulate filler is <5 g/cm 3 .

16. An electrically insulating layer on a substrate, comprising an elastomer and a field-controlling particulate filler, where the field-controlling particulate filler is metal-oxide-containing core-shell particles, the core of the core-shell particles comprises a dielectric material and the shell comprises at least one electrically conductive or electrically semiconductive metal oxide, and the elastomer is a silicone rubber.

17. The electrically insulating layer according to claim 16 , having a density of the metal-oxide-containing core-shell particles<5 g/cm 3 , and the distribution of these in the elastomer is homogeneous.

18. The electrically insulating layer according to claim 16 , having a volume resistivity of 10 8 to 10 13 ohm*cm.

19. The electrically insulating layer according to claim 16 , wherein the substrate is an HVDC cable having, at least partially, an electrically conductive surface.

20. An insulating layer in a cable sleeve, a cable end seal, a cable plug or a cable bushing for HVDC cables, comprising in said insulating layer, end seal, plug or bushing an electrically insulating layer according to claim 16 .

Assignees

• Merck Patent Gmbh

Inventors

• Greb Marco
• Bauer Johann
• Kurda Norbert

Classifications

• H02G15/184

  with devices for relieving electrical stress · CPC title

• H01B1/24

  the conductive material comprising carbon-silicon compounds, carbon or silicon · CPC title

• H02G1/145

  Moulds · CPC title

• H02G15/103 Primary

  with devices for relieving electrical stress · CPC title

• H02G1/14

  for joining or terminating cables · CPC title