Cable fitting for connecting a high-voltage cable to a high-voltage component or another high-voltage cable

Patent metadata

Field	Value
Publication number	US-10141683-B2
Application number	US-201815935738-A
Country	US
Kind code	B2
Filing date	Mar 26, 2018
Priority date	Sep 25, 2015
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

A high-voltage cable fitting with a rigid core insulator that has a first conical outer surface extending concentrically about a longitudinal axis. An elastomeric stress relief element has a first conical inner surface is designed for mating the first conical outer surface at an interface. A rigid member is provided for pressurizing the elastomeric stress relief element at the interface. The stress relief element is pressed onto the rigid core insulator. The rigid member has at least one pressure enhancing portion extending circumferential about the longitudinal axis for causing an additional axial expansion stress in a sleeve portion of the stress relief element extending along the first conical outer surface of the core insulator in an assembled state of the cable fitting.

First claim

The invention claimed is:

1. A high-voltage cable fitting, comprising:
a rigid core insulator with a cavity for receiving a conductor, wherein the rigid core insulator has a first conical outer surface extending concentrically about a longitudinal axis defined by the columnar overall shape of the high-voltage cable fitting,
an elastomeric stress relief element having a first conical inner surface designed for mating the first conical outer surface over a predefined length at an interface,
a rigid member provided for pressurizing the elastomeric stress relief element at the interface, and the rigid member has at least one pressure enhancing portion extending circumferentially about the longitudinal axis for causing an additional axial expansion stress in a sleeve portion of the stress relief element extending along the first conical outer surface of the core insulator in an assembled state of the cable fitting,
wherein at a given annular zone on the interface a diameter of the first conical inner surface is smaller than a diameter of the first conical outer surface in an unassembled state of the high-voltage cable fitting, and that the stress relief element is pressed onto the rigid core insulator, and in that:
(a) the stress relief element is cup-shaped and has an opening formed by the first conical inner surface and a circumferential collar directed radially outwards and a first end face located at the entry of said opening, and in that the rigid member has an inner contour for receiving the stress relief element, wherein the pressure enhancing portion is located at the inner contour such that it engages with the collar such that an additional axial expansion stress in the sleeve portion of the stress relief element extending along the first conical outer surface of the core insulator is caused in an assembled state of the cable fitting, and the pressure enhancing portion has a horn-shaped cross-section extending circumferentially about the longitudinal axis; or
(b) the rigid member has an inner contour that is directed towards the stress relief member, wherein the pressure enhancing portion comprises a plurality of stepped shoulders arranged at that inner contour at least in an area facing the first conical outer surface,
wherein the plurality of stepped shoulders are inclined with respect to the longitudinal axis about an inclination angle,
and in that the stress relief element is cup-shaped having an opening formed by the first conical inner surface, and a first end face located at the entry of said opening, wherein the stress relief element has an outer contour that is directed towards the rigid member and has a plurality of counter-shoulders for interacting with the stepped shoulders of the rigid member such that an additional axial expansion stress in the sleeve portion of the stress relief element is caused in an assembled state of the cable fitting; or
(c) the pressure enhancing portion is a sleeve-shaped pressure body provided between the stress relief member and the rigid member, wherein said pressure body has a second conical inner surface that is matching a second conical outer surface of the stress relief element at least in an area facing the first conical outer surface, and in that a compression system is provided between an axial end face of the pressure body and the rigid member for exerting an axial force on the pressure body in an assembled state of the cable fitting such that an additional axial expansion stress in the sleeve portion of the stress relief element is caused in an assembled state of the cable fitting.

2. The cable fitting according to claim 1 , which further includes at least one of a ring-shaped first gap in between a lateral shell surface of the stress relief element and the inner contour of the rigid member, and a ring-shaped second gap in between the collar of the stress relief element and the inner contour of the rigid member.

3. The cable fitting according to claim 1 , alternative (b), wherein the inclination angle of the stepped shoulders is about 90 degrees with respect to the longitudinal axis.

4. The cable fitting according to claim 3 , which further includes a support ring arranged in between each one of the plurality of shoulders and contour-shoulders.

5. The cable fitting according to claim 1 , alternative (b), wherein the inclination angle of the stepped shoulders is in a range of 30 to 80 degrees with respect to the longitudinal axis.

6. The cable fitting according to claim 1 , alternative (c), wherein the compression system comprises a plurality of compression springs.

7. The cable fitting according to claim 1 , wherein the cable fitting comprises a rigid flange extending circumferentially about the rigid core insulator and having a second end face directed towards the first end face of the stress relief element,
and which further includes a ring-shaped third gap in between the first end face of the stress relief element and the second end face of the flange.

8. The cable fitting according to claim 1 , alternative (b), wherein the rigid member has a bell-shaped cross-section with a tapered portion whose second cone angle is deviating from a first cone angle of the first conical outer surface by less than 30 degrees with respect to the longitudinal axis.

9. The cable fitting according to claim 1 , wherein the rigid core insulator is a condenser core having at least one electrically conducting field grading layer enclosed in between neighboring spacer layers.

10. The cable fitting according to claim 9 , wherein the spacer layers comprise polymer or glass fibers and a hardenable resin comprising inorganic filler particles.

11. The cable fitting according to claim 1 , which further includes an electrically conductive connector shield integrated into the stress relief element such that it contacts the first conical outer surface of the core insulator at its thinner end in an assembled state of the cable fitting,
and in that an electrically conductive field deflector is integrated into the stress relief element such that it contacts the first conical outer surface of the core insulator in an assembled state of the cable fitting at its thicker end and extends over an outer surface of the stress relief element.

12. A high voltage apparatus comprising a cable fitting according to claim 1 , wherein a high-voltage cable is connected to the conductor and wherein the stress relief element is exerting a radial compression force on the high-voltage cable in that it is pressed on the high-voltage cable.

13. A high-voltage cable fitting, comprising:
a rigid core insulator with a cavity for receiving a conductor, wherein the rigid core insulator has a first conical outer surface extending concentrically about a longitudinal axis defined by the columnar overall shape of the high-voltage cable fitting,
an elastomeric stress relief element having a first conical inner surface designed for mating the first conical outer surface over a predefined length at an interface,
a rigid member provided for pressurizing the elastomeric stress relief element at the interface, and the rigid member has at least one pressure enhancing portion extending circumferentially about the longitudinal axis for causing an additional axial expansion stress in a sleeve portion of the stress relief element extending along the first conical outer surface of the core insulator in an assembled state of the cable fitting,
wherein at a given annular zone on the interface a diameter of the first conical inner surface is smaller than a diameter of the first conical outer surface in an unassembled state of the high-voltage cable fitting, and that the stress relief

Assignees

• Abb Schweiz Ag

Inventors

• Czyzewski Jan
• Maurer Victoria
• Lichy Radim
• Sörqvist Torbjörn

Classifications

• H01R13/59

  Threaded ferrule or bolt operating in a direction parallel to the cable or wire · CPC title

• H02B13/0358

  Connections to in or out conductors (connectors in general H01R) · CPC title

• H01R13/5205

  Sealing means between cable and housing, e.g. grommet (H01R13/5221 takes precedence) · CPC title

• H01R13/53 Primary

  Bases or cases for heavy duty; Bases or cases {for high voltage} with means for preventing corona or arcing · CPC title

• H02G15/007

  Devices for relieving mechanical stress · CPC title