Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
  • H02G15/00—Cable fittings
  • H02G15/02—Cable terminations
  • H02G15/06—Cable terminating boxes, frames or other structures
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
  • H02G15/00—Cable fittings
  • H02G15/02—Cable terminations
  • H02G15/06—Cable terminating boxes, frames or other structures
  • H02G15/064—Cable terminating boxes, frames or other structures with devices for relieving electrical stress
  • H02G15/068—Cable terminating boxes, frames or other structures with devices for relieving electrical stress connected to the cable shield only

Definitions

• Protective sleeve provided with a conductive end for a cable end.
• the present invention relates to a sleeve for protecting a cable end such as a high or very high voltage electricity transmission cable.
• one end of the cable comprises a conductor, an insulating envelope disposed around the conductor and having one end recessed relative to the end of the conductor, and a conductive cable screen disposed around the insulating envelope.
• the protective sleeve is placed astride the cable end and the conductive end piece in order to protect the interface between the conductive end piece and the end of the insulating jacket against the deposition or infiltration of pollution or water from bad weather.
• the protective sleeve is made of insulating and elastic material, and comprises a tubular body maintained in an expanded state by a rigid tube. After crimping the conductive end piece, the operator positions the tubular body so that it covers the conductive end piece and the cable end and, while holding the tubular body firmly in position, proceeds to remove the rigid tube by exerting traction on the tube in a direction opposite to the conductive end piece. The tubular body then retracts onto the conductive end piece and the cable end.
• An object of the invention is to provide a protective sleeve whose installation is easy and allows precise positioning.
• a protective sleeve at one end of the cable comprising a tubular body of insulating material, one end portion of which is in a retracted state and tightly encloses part of a conductive tip while an adjacent part of the tubular body is in an expanded state.
• the conductive end piece once in abutment and / or fixed on the cable end constitutes a fixed point of positioning of the tubular body.
• the conductive endpiece thus opposes any displacement of the tubular body in the direction of traction and ensures the maintenance in position of the tubular body during the withdrawal of the rigid tube.
• the fitting of the sleeve is therefore easy and quick.
• the part of the conductive end piece extending inside the tubular body carries at least one clamping screw, preferably with a fusible head, extending radially through the conductive end piece and of an adjacent portion of the tubular body, and the tubular body has an elastic outer flange adjacent to the clamping screw.
• the tubular body comprises a conductive layer opening onto an internal face of the tubular body straddling the end portion in a retracted state and on the adjacent part in an expanded state.
• the conductive layer covers both the conductive end piece and the insulating envelope.
• the conductive layer then forms a Faraday cage limiting the formation of electrical stresses at the interface between the conductive end piece and the insulating envelope.
• FIG. 1 is a view in longitudinal section of a protective sleeve according to the invention positioned on one end of the cable,
• Figure 2 is a view similar to Figure 1 of the protective sleeve retracted on the end of the cable.
• one end of the cable comprises a cylindrical conductor 1 conventionally formed from a series of stranded conductive wires, an insulating jacket 2 disposed around the conductor and having one end 3 set back from the end of conductor, a conductive cable screen 4, disposed around the insulating jacket 2 and having one end set back from the end 3 of the insulating jacket, a metal shield 5 arranged around the cable screen and having one end set back from the end of the cable screen, an insulating sheath 6 surrounding the shield 5, and a grounding braid, not shown, in contact with the end of the shield.
• the insulating sheath, the shielding, the cable screen and the insulating envelope have a generally cylindrical structure and extend in successive layers around the conductor.
• the protective sleeve, bearing the general reference 7 comprises a tubular body 8 made of insulating and elastic material so as to be able to be radially expanded, and a series of skirts 9 projecting towards the outside around the tubular body 8.
• the tubular body has, when it is in a state of rest, an internal diameter smaller than the minimum diameter of the cable end that it is intended to cover.
• the tubular body 8 comprises an end portion 10 in a retracted state surrounding a tubular part 12 of a tip 11 made of a conductive material.
• the tubular part 12 has an external diameter greater than the internal diameter of the tubular body 8 in a state of rest so that when the end portion 10 of the tubular body is in a retracted state it tightly encloses the conductive end piece 11.
• the conductive endpiece 11 carries two clamping screws 14 with controlled breaking force extending radially through the part 12 and the end portion 10 of the tubular body 8.
• a part 15 of the tubular body 8 adjacent to the end portion 10 is maintained in an expanded state by a rigid expanding holding tube 16.
• the expanding holding tube 16 has an internal diameter greater than the maximum diameter of the end of cable on which it is intended to be threaded.
• a conductive layer 17 extends annularly astride the end portion 10 and the part 15 of the tubular body 8.
• the conductive layer 17 opens onto the internal face 18 of the tubular body 8.
• the conductive layer 17 is for example made of a polymer made electrically conductive.
• the tubular body 8 also comprises an elastic external flange 19 adjacent to the clamping screws 14.
• the operator threads the protective sleeve 7 on the cable end until the tubular part 12 of the conductive end piece 11 abuts on the end 3 of the insulation 2.
• the operator then screws the clamping screws 14 to fix the conductive end piece 11 on the conductor 1.
• the screws are designed to break when the screwing force is greater than a force corresponding to sufficient tightening of the conductor 1, so that the broken screw is flush with the outer surface of the conductive tip.
• the operator can therefore proceed to withdraw the expansion holding tube 16 by exerting a traction thereon in a direction opposite to the conductive end piece 11, to which the tubular body 8 is hooked by the end portion 10.
• the part 15 of the tubular body 8 then retracts onto the cable end as shown in FIG. 2.
• the conductive layer 17 is in this way in close contact with both the conductive tip 11 and the insulating envelope 2 and thus forms a Faraday cage around the interface between the conductive tip 11 and the insulating envelope 2 .
• the retracted state of the end portion 10 of the tubular body 8 can result either from a total expansion of the tubular body 8 then its partial retraction in the workshop on the conductive end piece, or from a fitting of the end piece conductor followed by partial expansion of the tubular body. If necessary, the conductive end piece can also be glued to the tubular body. Although the conductive endpiece is fixed to the conductor by screwing in the embodiment described, it could be fixed by deep crimping, necked hexagonal or the like.
• the protective sleeve has been represented in the form of a single layer directly applied to the cable, it is possible to provide a protective sleeve comprising an internal layer with high permittivity reducing electrical stresses, which makes it possible to reduce the length of the end without reducing its performance.
• a conductive field deflector can also be incorporated into the device.

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• Cable Accessories (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9509756

Family Applications (1)

Country Status (3)

Family Cites Families (4)

• 1997
  • 1997-07-29 FR FR9709635A patent/FR2766982B1/fr not_active Expired - Fee Related
• 1998
  • 1998-07-27 EP EP98940343A patent/EP1000451A1/de not_active Withdrawn
  • 1998-07-27 WO PCT/FR1998/001654 patent/WO1999007051A1/fr not_active Ceased

Non-Patent Citations (1)

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