Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B9/00—Power cables
  • H01B9/02—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients
  • H01B9/023—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients composed of helicoidally wound tape-conductors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B9/00—Power cables
  • H01B9/02—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients
  • H01B9/022—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients composed of longitudinal lapped tape-conductors

Definitions

• the invention relates to an electrical cable with at least one electrical conductor and a multi-layer insulation system enclosing it, which has an insulation sheath, at least one semiconductor layer, a metal shield enveloping it and an outer jacket, the metal shield serving as a neutral conductor having a along the Cable extending overlap point is provided.
• An electrical cable of the generic type according to Swiss patent application No. 00 610 / 92-4 is preferably suitable as a medium voltage cable for voltages between 10 and 50 kV or as a high voltage cable up to 420 kV.
• a centrally arranged electrical conductor produced from a plurality of copper or aluminum wires stranded together and from a multilayer insulation which surrounds the latter in an annular manner, which consists of a first semiconductor layer surrounding the conductor, and one made of an aging-resistant plastic, for example of cross-linked polyethylene , existing insulating sleeve, a second semiconductor layer, a swelling tape, a neutral conductor and an outer jacket made of plastic.
• the neutral conductor which is ring-shaped in cross section, is formed from a metal foil strip which is wrapped around the swelling band and completely envelops it and which forms an overlap point with its band edges.
• This known electrical cable which can be single-core or a three-conductor cable, can be manufactured in an extremely compact manner and has a high resistance to aging.
• the same When the same is laid, for example, in a cable pipe or the like laid in the ground, it is constantly exposed to moist ambient air in many applications and, despite the outer sheath consisting of plastic, water vapor particles can infiltrate in this, thereby increasing the service life of this insulation and thus of the cable can decrease.
• the object of the present invention is to develop an electrical cable of the type described in the introduction in such a way that, with simple manufacture presupposed, neither liquid nor moisture, in particular water vapor, can penetrate into the interior and achieve an increased resistance to aging compared to conventional cables becomes.
• the object is achieved in that the metal screen is joined at its overlap point in a sealing manner throughout the entire cable length, preferably by means of an adhesive, and thus forms a liquid and vapor-barrier protective sheath of the cable interior.
• the entire inside of this metal screen is provided with an adhesive designed as a semiconductor, which is designed as a film and is attached to the inside of the metal screen before the cable is manufactured.
• This electrical cable according to the invention offers absolute tightness, in particular in the case of simple and therefore inexpensive production, in particular before moisture and liquid penetrate.
• the inside of this metal screen is protected against corrosion by the adhesive film attached to it.
• FIG. 1 is the only figure showing a perspective view of an electrical cable according to the invention, illustrated in section on the end face.
• FIG. 1 shows an electrical cable 10, which is used in particular for medium voltages in a voltage range between 10 and 50 kV or for high voltages up to 420 kV, and an electrically arranged center made of a plurality of copper or aluminum wires 14 or the like which are stranded together ⁇ trical conductor 12 and a multi-layer insulation system enclosing this.
• the latter has a semiconductor layer 15 surrounding the electrical conductor 12, an insulation sleeve 16 encompassing it, an outer semiconductor layer 17, a metal shield 20 enveloping the latter and serving as a neutral conductor, and an outer jacket 18.
• An aluminum foil strip is provided for the metal screen 20, which is placed along the cable around the outer semiconductor layer 17 and has such a width that it forms an overlap point 22 extending along the cable 10.
• the band edges over lapping at an angle of at least 10 °, but they could overlap to such an extent that this metal screen would be sheathed two or more times around the interior of the cable.
• the metal screen 20 is joined at its overlap point 22 in a sealing manner over the entire cable length by means of an adhesive 23 and thus forms a liquid and vapor impermeable protective sheath for the inside of the cable.
• the adhesive 23 is applied to the entire inside of the metal screen 20, advantageously in the form of a semiconductor film, and is glued to the inside of the metal screen 20 by a pressing process before the cable is manufactured.
• the adhesive 23 expediently consists essentially of an adhesive material and of chemically produced carbon black, and its formation as a semiconductor enables electrical contact from the metal screen to the outer semiconductor layer 17, despite the adhesive film located between them in full.
• a swelling band 19 likewise formed as a semiconductor, is advantageously inserted, which primarily has two functions.
• this swelling band 19 absorbs the water penetrating into the cable interior as well as the moisture, and the strong swelling of the latter causes the water to continue flowing in the longitudinal direction of the cable prevented.
• this swelling tape 19 performs a cushioning function, in particular the insulation sleeve 16, which changes in the outer diameter when the cable is laid, and the semiconductor layer 17 surrounding it.
• This swelling tape 19 is made of a nonwoven fabric or the like with a plastic coating applied to the inside as well as to the outside, the latter being mixed with carbon particles, which give the source tape the semiconducting property as a whole.
• the first semiconductor layer 15, the insulation sheath 16 and the outer semiconductor layer 17 are first pulled on one after the other. Then the swelling tape 19 is applied around the outer semiconductor layer 17 and then the tape-shaped metal screen 20 is placed around it and glued to the overlap point 22 by heating it up, for example to approximately 120 ° Celsius. Finally, the outer jacket 18, in which a tough polyethylene insulation material is used, is drawn around the metal screen 20, with a vacuum or partial vacuum advantageously being created between these to create perfect adhesion of this outer jacket to the metal screen, or the Outer jacket 18 is applied to the metal screen 20 by means of a press extrusion, in which the metal screen 20 is pulled onto the metal screen with pressure.
• Such an electrical cable generally has an outside diameter between 10 and 70 millimeters. It is used individually or as a three-wire cable, the three individual cables being twisted together in the latter application and being held together by a sheath comprising them.
• the foil strip used as a metal screen can also be made of copper or another electrically conductive material.
• the point of overlap of this film strip does not necessarily have to run parallel to the conductor along the cable, but the film could also be wound helically or in successive layers around the cable.

Landscapes

• Insulated Conductors (AREA)
• Inorganic Insulating Materials (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=4193643

Family Applications (1)

Country Status (6)

Families Citing this family (1)

Family Cites Families (3)

• 1995
  • 1995-03-14 CH CH00721/95A patent/CH690473A5/de not_active IP Right Cessation
• 1996
  • 1996-03-12 WO PCT/CH1996/000091 patent/WO1996028830A1/fr not_active Ceased
  • 1996-03-12 DE DE59601264T patent/DE59601264D1/de not_active Expired - Fee Related
  • 1996-03-12 AT AT96905648T patent/ATE176547T1/de not_active IP Right Cessation
  • 1996-03-12 EP EP96905648A patent/EP0815567B1/fr not_active Revoked
  • 1996-03-12 AU AU49360/96A patent/AU4936096A/en not_active Abandoned

Non-Patent Citations (1)

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