US2067169A - Electric cable - Google Patents

Electric cable Download PDF

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Publication number
US2067169A
US2067169A US653763A US65376333A US2067169A US 2067169 A US2067169 A US 2067169A US 653763 A US653763 A US 653763A US 65376333 A US65376333 A US 65376333A US 2067169 A US2067169 A US 2067169A
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United States
Prior art keywords
paper
gas
spaces
cable
conductor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US653763A
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English (en)
Inventor
Beaver Charles James
Davey Edward Leslie
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WT Glover and Co Ltd
Original Assignee
WT Glover and Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by WT Glover and Co Ltd filed Critical WT Glover and Co Ltd
Application granted granted Critical
Publication of US2067169A publication Critical patent/US2067169A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B9/00—Power cables
    • H01B9/06—Gas-pressure cables; Oil-pressure cables; Cables for use in conduits under fluid pressure
    • H01B9/0644—Features relating to the dielectric of gas-pressure cables
    • H01B9/0655—Helically wrapped insulation

Definitions

  • this method imposes comparatively low limits on the viscosity of the impregnating compound in order that it may penetrate the Wall of dielectric.
  • Thedimensions areassured (1) by forming the spaces in the process of lapping on the paper layers so that they are determined radially by the thickness of the paper, and longitudinally by the spacing of thellappings in each layer, and (2) by providing that these spaces are substantially clear of free compound; that is,rthe compound is present only in the paper and on its surfaces and is retained there.
  • the paper for use in the manufacture of a cable in accordance with the present invention is impregnated before application to the conductor with a compound having such a setting point as to ensure that physical stability of the impregnated paper is maintained up to a temperature Well above the maximum reached in the working conditions of the cable.
  • the impregnation may, for instance, be carried out as set out in the specification of U. S. A. Patent No. 1,752,972 or of U. S. A. Patent No. 1,958,984.
  • the paper may be provided with a lubricating iilm as described in the said specications.
  • This film is preferably applied to one side of the paper only and is of verysmall thickness. It may, for instance, consist of a coating of petroleum jelly having a high viscosity and set point.
  • the conductor l is covered with a thin metal tape or foil 2 and is lapped with layers or laminae of paper strip indicated by the reference numerals 3, 4 and 5.
  • a metallized layer 6 (preferably perforated) and over this the lead sheath 'l is applied.
  • a metal reinforcing tape 8 is applied to the outside of the lead sheath and ⁇ this is protected in the usual way by layers of impregnated fabric 9.
  • the metal tape 2, the metallized paper 6, the reinforcing tape 8 and the fabric layers 9 will as usual be lapped on helically. No attempt has inite inner cylindrical surface to the dielectric layer.
  • the strips or wrappings of the preimpregnated paper are lapped on the cable in air which' is preferably kept below, normal humidity and the cable is then sheathed with lead or lead alloy with or without reinforcement.
  • the air enclosed in the dielectric which is chiefly located in the spaces provided between the turns of paper, may be evacuated and replaced by an inert dry gas, such as nitrogen. carbon dioxide or other suitable gas.
  • an inert dry gas such as nitrogen. carbon dioxide or other suitable gas.
  • the process or removal of air and filling with gas may be facilitated by a repeated flooding and exhausting of the gas into and from the cable and by the application of heat to the cable intermittently or continuously, either by external means or by the passage of current through the conductor or conductors or by both of these.
  • a gas cylinder can be left connected to the cable through a non-return valve so as to maintain the pressure within the cable if accidental lowering should occur.
  • 'I'he gas pressure is chosen in relation to the thickness of gas lms formed in the dielectric, which is determined by the thickness of the individual layers of paper, so that according to well known laws the ionization point of the films of gas exceeds by a predetermined margin the working stress in the dielectric.
  • the cable may be finally nlled with dry air under pressure, but a preliminary evacuation and heating may also be required in this case.
  • the choice of the radial dimensions of the gas spaces and of the gas pressure will depend upon a number of conditions. It will however generally be advantageous to make the gas spaces of small radial dimensions, for instance, one or one and a half thousandths of an inch. With such dimensions and with only a comparatively moderate gas pressure, for instance, flften pounds per square inch above atmosphere, very material increase in the ionization point can be obtained in cables constructed in accordance with the'inven tion. It is of course possible to use other dimensions and higher pressures, the choice of pressure being materially affected by the cost of strengthening or reinforcing the sheath which it may require. This may, however, in some cases be offset by the reduction in diameter which can be obtained by increase in pressure.
  • the radial dimensions of the gas spaces may also be increased, taking advantage of the fact that the intensity of electric stress decreases from thc surface of the conductor outwards. This is indicated diagrammatically in the drawing where three different thicknesses of paper are intended to be indicated for the regions I, I and I respectively.
  • suitable values for the thicknesses of the paper lamina: or wrappings for this example are:-
  • Region 3 a thickness of 1.75 thousandths of an inch.
  • Region 4 a thickness of 2.5 thousandths of an inch.
  • Region 5 a thickness of 3.75 thousandths of an inch.
  • the type of cable illustrated in the drawing may be used with gas pressures up to 200 lbs per square ⁇ inch and considerably higher.
  • the solid portion of the dielectric namely the impregnated paper
  • the gaseous content of the cable is preventedfrom undergoing appreciable alteration of form, position and dimensions and therefore from becoming ionizable.
  • the compressibility provided by the gaseous content of the cable prevents the application of excessive pressure to the reinforced sheath such as would produce permanent distension.
  • An electric cable comprising a conductor, a sheath and a dielectric layer between the conductor and the sheath, the said layer comprising turns of impregnated paper spaced apart to provide intervening compound-free spaces, the thickness of the paper and the corresponding radial dimensions of the spaces increasing from the conductor outwards, and gas under pressure substantially above that of the atmosphere filling said spaces.
  • An electric cable comprising a conductor, an enclosing sheath and a dielectric layer between the conductor and the sheath, said layer comprising wrapped paper impregnated with highly viscous compound, and gas at a pressure substantially above that of the atmosphere, which gas occupies spaces in the dielectric layer of dimensions predetermined in size so as to avoid ionization of gas and which spaces are substantially invariable in position and dimensions and are substantially clear of free compound under all working conditions, which Vspaces are distributed through the dielectric layer.
  • An electric cable comprising a conductor
  • an enclosing sheath and a laminated dielectric layer between the conductor and the sheath said layer comprising wrapped paper impregnated with highly viscous compound, and gas at a pressure substantially above that of the atmosphere, which gas occupies spaces in the dielectric layer of substantially invariable dimensions which are bounded by the turns and laminae of the paper, which spaces are substantially clear of free compound under all working conditions.
  • An electric cable comprising a conductor, an enclosing sheath and a laminated dielectric layer between the conductor and the sheath, said layer comprising paper impregnated with a compound which has a high setting temperature above the range of the working temperature of the cable and which compound is thereby retained in and confined to the paper under all working conditions, said layer also comprising gas at a pressure substantially above that of the atmosphere, which gas occupies spaces of substantially invariable dimensions, which spaces are bounded by the turns and laminae of the paper.
  • An electric cable comprising a conductor, an enclosing sheath and a dielectric layer between the conductor and the sheath, said dielectric layer comprising wrapped paper impregnated with a highly viscous compound, said layer having helical spaces therein of mechanically predetermined locations and dimensions such that the dielectric strength of any radial dimension of said layer is predetermined, said spaces having gas therein at a pressure above atmospheric, the spaces being formed between edges oi adjacent turns of paper and between surfaces of concentric wrappings.
  • An electric cable comprising a conductor. an enclosing sheath and a. dielectric layer between the conductor and the sheath, said'layer having helical spaces therein of mechanically predetermined locations and dimensions, said dielectric layer comprising wrapped paper impregnated with a highly viscous compound, the spaces being formed between edges of .adjacent turns of paper and between surfaces of concentric wrappings, said spaces having gas therein at a pressure above atmospheric, the dielectric strength of each part of said layer being predetermined by the dimensions of the spaces and the gas pressure.
  • An electric cable comprising a conductor, an enclosing sheath and dielectric material between the conductor and the sheath, said material being constituted by definitely spaced turns and layers of paper tape of predetermined thickness, which tape is fully impregnated with a highly viscous compound which is conned to the paper under all working conditions, and gas at a pressure substantially above that of the atmosphere occupying all the spaces between the turns and layers of paper tape.
  • An electric cable comprising a conductor, an enclosing sheath and dielectric material between the conductor and the sheath, said material being constituted by definitely spaced turns and layers of paper tape of predetermined thickness, which tape is fully impregnated with oil4 compound which has a setting point higher than the working temperature of the cable, whereby the compound is coniined to the paper under all working conditions and gas at a pressure substantially above that of the atmosphere occupying all the spaces between the turns and layers of paper tape.
  • An electric cable comprising a conductor, an enclosing sheath and dielectric material between the conductor Aand the sheath, said material being constituted by turns and layers of paper tape with spaces of denite and substantially invariable dimensions between the turns and of increasing radial dimensions from the conductor outwards, said tape being fully impregnated with compound which is coniined to the paper under all working conditions and by a gas at a pressure substantially above that of the atmosphere occupying all the spaces between the turns and layers of paper tape.
  • An electric cable comprising a conductor, an enclosing sheath and dielectric material between the conductor and the sheath, said material being constituted by turns and layers of paper tape with spaces of definite and substantially invariable dimensions between the turns and of increasing radial dimensions from the conductor outwards, said tape being fully impregnated with oil compound which has a setting point above the range of the working temperature of the cable, whereby the compound is conned to the paper under all working conditions and by a gas at a pressure substantially above that of the atmosphere occupying all the spaces between the turns and layers of paper tape.

Landscapes

  • Insulated Conductors (AREA)
  • Ropes Or Cables (AREA)
  • Manufacturing Of Electric Cables (AREA)
US653763A 1932-02-09 1933-01-27 Electric cable Expired - Lifetime US2067169A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB167915X 1932-02-09

Publications (1)

Publication Number Publication Date
US2067169A true US2067169A (en) 1937-01-12

Family

ID=10083725

Family Applications (1)

Application Number Title Priority Date Filing Date
US653763A Expired - Lifetime US2067169A (en) 1932-02-09 1933-01-27 Electric cable

Country Status (6)

Country Link
US (1) US2067169A (enrdf_load_stackoverflow)
CH (1) CH167915A (enrdf_load_stackoverflow)
DE (1) DE857514C (enrdf_load_stackoverflow)
FR (1) FR749408A (enrdf_load_stackoverflow)
GB (1) GB393694A (enrdf_load_stackoverflow)
NL (1) NL37000C (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532152A (en) * 1944-02-25 1950-11-28 Comp Generale Electricite Thin paper insulated electric cable
US2668186A (en) * 1948-05-28 1954-02-02 Comp Generale Electricite Electric cable with oil pressure outside the insulation
US2709197A (en) * 1949-10-13 1955-05-24 Glover & Co Ltd W T Electric cables
US4774382A (en) * 1986-07-16 1988-09-27 Societa' Cavi Pirelli S.P.A. Direct current cable insulation with insulating composition including electronegative gas

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1011952B (de) * 1952-07-26 1957-07-11 Hackethal Draht & Kabelwerk Ag Unter Druck stehende elektrische Isolierung, insbesondere fuer Hochspannungskabel
AT515133A1 (de) * 2013-11-25 2015-06-15 Seebacher Theodor Ernst Vorrichtung zur Stromübertragung unter Hochspannung

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532152A (en) * 1944-02-25 1950-11-28 Comp Generale Electricite Thin paper insulated electric cable
US2668186A (en) * 1948-05-28 1954-02-02 Comp Generale Electricite Electric cable with oil pressure outside the insulation
US2709197A (en) * 1949-10-13 1955-05-24 Glover & Co Ltd W T Electric cables
US4774382A (en) * 1986-07-16 1988-09-27 Societa' Cavi Pirelli S.P.A. Direct current cable insulation with insulating composition including electronegative gas

Also Published As

Publication number Publication date
DE857514C (de) 1952-12-01
GB393694A (en) 1933-06-15
CH167915A (fr) 1934-03-15
NL37000C (enrdf_load_stackoverflow)
FR749408A (fr) 1933-07-24

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