US3885085A - High voltage solid extruded insulated power cables - Google Patents

High voltage solid extruded insulated power cables Download PDF

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Publication number
US3885085A
US3885085A US478329A US47832974A US3885085A US 3885085 A US3885085 A US 3885085A US 478329 A US478329 A US 478329A US 47832974 A US47832974 A US 47832974A US 3885085 A US3885085 A US 3885085A
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United States
Prior art keywords
insulation
shield
electric power
emission
power cable
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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
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US478329A
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English (en)
Inventor
George Bahder
Jr George S Eager
David A Silver
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General Cable Corp
Original Assignee
General Cable Corp
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Filing date
Publication date
Application filed by General Cable Corp filed Critical General Cable Corp
Priority to US478329A priority Critical patent/US3885085A/en
Priority to FR7504593A priority patent/FR2273352A1/fr
Priority to IT48183/75A priority patent/IT1040565B/it
Priority to JP50019502A priority patent/JPS51682A/ja
Priority to ES434861A priority patent/ES434861A1/es
Priority to GB1150475A priority patent/GB1458493A/en
Priority to DE19752517589 priority patent/DE2517589A1/de
Priority to BR2579/75A priority patent/BR7502579A/pt
Priority to CA225,702A priority patent/CA1031428A/en
Application granted granted Critical
Publication of US3885085A publication Critical patent/US3885085A/en
Priority to SE7506698A priority patent/SE7506698L/xx
Priority to ES1975215398U priority patent/ES215398Y/es
Priority to JP1983102863U priority patent/JPS5955816U/ja
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/22—Sheathing; Armouring; Screening; Applying other protective layers
    • H01B13/24—Sheathing; Armouring; Screening; Applying other protective layers by extrusion
    • 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

Definitions

  • ABSTRACT This electric power cable, and method of making it, relate to high voltage cables with solid extruded insulation, and the life of the cable is lengthened by protecting the insulation from localized voltage stresses which cause emission of electrons into the insulation.
  • An emission shield is used between a semi-conducting conductor shield and the insulation that surrounds the conductor shield; and preferably, for higher voltage
  • This invention is a new construction for solid extruded insulated power cable and a corresponding new method of manufacture.
  • the preferred insulation is cross-linked polyethylene, but the invention is applicable to other polyethylene and other extruded polymeric insulation.
  • the applicable voltage range is kilovolts through 345 kilovolts, and may be extended to higher voltages.
  • the cable is preferably made by utilizing a new technology in the treatment of the pelletized insulation material received from material suppliers. This treatment consists of crushing" contaminants, and in the case of cross-linked polyethylene, more extensively dispersing the peroxide curing agent.
  • the treatment alternately can include straining through small dies of the polyethylene insulation prior to extrusion or in the case of chemically cross-linked polyethylene straining prior to the addition of di-cumyl peroxide, the curing agent. This results in higher dielectric strength and consequently permits the use of thinner insulation thickness.
  • This treatment is the subject matter of a patent applica tion referred to later in this specification.
  • the term contaminants is used to designate voids and similar imperfections in the plastic material; and also to designate impurities and concentrations of curing agent.
  • Extruded high voltage cables made with polyethylene and cross-linked polyethylene should have a minimum of imperfections in order to have a life span as long as 30 years or more. Such imperfections also affect other plastic materials which are used for insulation such as ethylene-propylene rubber.
  • the semi-conducting conductor shield commonly used on our cables is modified in this invention by placing over it an emission shield comprising a layer of material such as neoprene chlorosulfonated polyethylene (Hypalon) or polyethylene containing a high dielective constant (SIC) material such as titanium dioxide which contains no electrical conducting particles.
  • an emission shield comprising a layer of material such as neoprene chlorosulfonated polyethylene (Hypalon) or polyethylene containing a high dielective constant (SIC) material such as titanium dioxide which contains no electrical conducting particles.
  • SIC high dielective constant
  • FIG. 1 is a side elevation of a cable made in accordance with this invention with layers successively broken away to illustrate underlying layers;
  • FIG. 2 is an enlarged sectional view taken on the line 2-2 of FIG. 1;
  • FIG. 3 is a Weibull diagram showing a difference between a conventional power cable with extruded insulation and a power cable which has insulation extruded from material where the imperfections have been reduced to a diameter of less than 0.001 inches;
  • FIG. 4 is a Weibull diagram showing the difference between a power cable having extruded insulation with the reduced size imperfections of FIG. 3 compared with a cable having the same reduced size imperfections with an emission shield located between a semiconducting conductor shield and the insulation of the cable in accordance with the invention.
  • FIG. 5 is a diagrammatic view showing apparatus for making a cable in accordance with this invention and also illustrating the method of making such a cable.
  • FIGS. 1 and 2 show a cable 10 made in accordance with this invention.
  • the cable has a conductor 12, which is shown as a stranded conductor.
  • a shield 13 is extruded over the conductor 12 in two layers.
  • the inner layer 14 is a semi-conducting shield and the outer layer 18 is an emission shield.
  • the cable 10 has an extruded insulation 16 that is applied over the shield 13.
  • the insulation 16 contacts with and is fused to the semi-conducting shield that surrounds the conductor; but in the illustrated construction the emission shielding layer 18 separates the semi-conducting conductor shield 14 from the insulation 16.
  • This emission shield 18 has a dielectric constant which is higher than several times that of the insulation l6 and the emission shield serves to smooth out electrical stresses which would otherwise exist at the interface between the semi-conducting conductor shield and the insulation, in a conventional cable which has the insulation applied directly over the semiconducting conductor shield.
  • the emission shield is preferably made of neoprene, Hypalon, polyethylene filled with a high dielectric constant (SIC) material such as titanium dioxide, or other flexible thermoplastic or thermosetting materials which have a dielectric constant several times higher than that of polyethylene or such other material as may be used for the insulation 16.
  • SIC high dielectric constant
  • the neoprene or hypolon, or other emission shield material should be free of any carbon black or other electrically conducting particles.
  • the emission shield 18 is preferably bonded to both the semi-conducting conductor shield 14 and to the insulation l6.
  • the dielectric constant of the emission shield 18 should be six or more.
  • the insulation 16 is preferably made of polyethylene or cross-linked polyethylene because of the good electrical characteristics of these materials. Other insulating material can be used in place of polyethylene, such as ethylene-propylene rubber or polyvinyl chloride. Both of these latter materials are well known insulating materials. If the insulation 16 is cross-linked, it may be cross-linked either chemically or by radiation, and the degree of cross-linking should be sufficient to raise the softening point of the insulation but not enough to produce a rigid layer since it is important that the cable be capable of bending without injury.
  • the cable 10 has a metallic shield 24 surrounding the insulation shield 22; and there is an overall plastic jacket 26 extruded over the outside of the metallic shield 24.
  • This plastic jacket 26 may be polyvinyl chloride or any other tough plastic such as is commonly used for mechanical protection for power cables.
  • the inner emission shield 18 should have a thickness in the range of 5 to 30 mils. it must be flexible and should be mechanically strong. it can be applied to the semi-conducting conductor shield 14 by painting it on the outside of the shield 14 or by extruding it over the shield 14.
  • the semi-conducting shield 14 haas surface irregularities and can have non-uniform distribution of carbon black particles at local areas. Both of these deficiencies lead to regions of high electrical stress. This high stress reduces the dielectric strength of the insulation. These high stress areas result in electron emission which causes aging of polyethylene or cross-linked polyethylene in cables which have no emission shield between the semi-conducting conductor shield and the insulation. The aging is responsible for lower values of voltage breakdown of the cable and this reduces the useful life of the cable.
  • the voltage stress is reduced at the surface irregularities at the interfaces and in regions of irregular carbon black distribution and this increases the breakdown voltage of the cable.
  • the outer emission shield 20, between the insulation 16 and the insulation shield 22 is further removed from the conductor 12 and is of larger area at a location where voltage stresses are not as high as at the first emission shield 18.
  • This outer emission shield 20 may be thicker or thinner than the inner emission shield 18. It is ordinarily somewhat thinner if the cable is made with the overall metal shield 24 and the outer plastic jacket 26 around the outside of the emission shield 20. If the cable is made without the shield 20 and jacket 26, then the emission shield 20 is preferably thicker than the inner emission shield l8.
  • the range of thickness for the shield 22, depending upon the conditions already described, is between 5 and 30 mils.
  • Extruded insulations such as polyethylene have an inherent a-c 60 Hz electrical breakdown strength in the range of 10,000 volts/mil.
  • a statistical study of commercial cables shows an average breakdown strength in the range 200 to 700 volts/mil. This is about onethirteenth to one-fiftieth the potential of the material used. The major cause of the extremely low values compared to the potential values is imperfections.
  • the dielectric strength of the insulating system with the emission shield will depend on the breakdown strength of the emission shield which can be expressed as follows:
  • Ees is approximately equal to Ei ki/kes where Ees the voltage breakdown in volts/mil of the emission shield Ei the voltage breakdown in volts/mil of the insulation ki the SlC (dielectric constant) of the insulation kes the 81C of the emission shield This equation is valid for Ees which is less than or equal to Ei.
  • the stranded conductor 12 may be copper or aluminum and an unstranded conductor can be used if desired.
  • a semiconducting tape may be placed around the conductor and the semi-conducting conductor shield 14 can be placed over the tape, or the semi-conducting tape can be used in lieu of the shield 14. in either case, the emission shield 18 should adhere to the underlying semi-conducting layer and should be of a range of thickness from 5 to 30 mils so as not to be damaged during handling of the cable.
  • the insulation shield 22 is preferably extruded, but can be made from a semi-conducting tape, if desired.
  • the metallic shield 24 can be made of copper folded longitudinally and with a lap seam which has edges free to move circumferentially over one another during heat cycling of the cable. ln place of such a metallic shield 24, helically applied copper wires, copper tape, copper ribbons or a lead sheath may be applied.
  • the emission shields l8 and 20 must not only be flexible so as to bend with the cable but should be made of material which ages as well as the polyethylene or cross-linked polyethylene or other material used for the insulation.
  • the emission shields should adhere to the insulation 16 and where the various layers are extruded, the heat of extrusion will usually provide the necessary fusion bonding for good adherence. it is, of course, necessary that the emission shields l8 and 20 be made of material which is compatible with the insulation l6 and the semi-conducting shields l4 and 22.
  • Neoprene and Hypalon compounds are examples of material which is particularly suitable for use with polyethylene insulation and with semi-conducting shields made of polyethylene through which carbon black has been dispersed to obtain the semi-conducting quality.
  • FIG. 3 shows a Weibull diagram with curve A illustrating the results obtained with a conventional production sample ofa power cable having insulation made of polyethylene but without any special treatment to reduce the diameter of imperfections in the polyethylene.
  • FIG. 3 shows a curve B which illustrates the results obtained with a comparable cable, to that of curve A, but with the insulation treated so that it contains no imperfections greater than about 3 mils in diameter. This is the improvement obtained by the Eager, Riley and Destito patent application previously referred to.
  • FIG. 4 shows another Weibull diagram in which a curve C represents a sample power cable having the imperfections of small size in accordance with the Eager, Riley and Destito patent application.
  • This curve C of FIG. 4 differs from curve B of FIG. 3 in that a different sample was used for the Weibull diagram of FIG. 4.
  • the technique used for reducing the size of imperfections was different for the insulation of curve C than for curve B and the characteristics are somewhat different though the actual values are not far apart over most of the range of the curves.
  • Curve D of FIG. 4 illustrates the results obtained by the addition of the emission shields of this invention to a cable such as represented by curve C.
  • Curves A and B of FIG. 3 and curves C and D of FIG. 4 may seem quite pronounced in viewing the diagrams of FIGS. 3 and 4, it should be recognized that the scales along the abscissa in both diagrams are logarithmic scales and that divisions of the scales toward the right represent progressively greater values of breakdown stress in volts per mil.
  • FIG. 5 is a diagrammatic showing of apparatus for making the cable shown in FIGS. 1 and 2.
  • the conductor 12 is supplied from a wire payoff 32.
  • the conductor 12 passes through an extruder 34 which extrudes the semi-conducting conductor shield 14 over the conductor 12.
  • the conductor with the semi-conducting shields passes through a first emission shield applicator 36 which applies the emission shield 18.
  • the insulation I6 is then applied by an insulation extruder 38.
  • Insulation for the extruder 38 is supplied from a pellet feeder 40 to a mixing screw 42. If the insulation is to be cross-linked chemically, then a cross-linking agent, such as peroxide is supplied from a peroxide reservoir 44 through a metering pump 46 to the insulating material which is being advanced by the mixing screw 42. The insulation and the peroxide are thoroughly blended in a blender 48 from which the insulation is advanced through a chamber 50 to the extruder 38.
  • a cross-linking agent such as peroxide is supplied from a peroxide reservoir 44 through a metering pump 46 to the insulating material which is being advanced by the mixing screw 42.
  • the insulation and the peroxide are thoroughly blended in a blender 48 from which the insulation is advanced through a chamber 50 to the extruder 38.
  • the conductor with the insulation applied to it travels through an emission shield applicator 52 in which the second emission shield is applied over the insulation 16.
  • the insulation shield 22 is then extruded by an extruder 54 over the outer emission shield 20 and the cable continues its travel through a continuous vulcanizer and curing apparatus 56.
  • Heat is applied to the cable in the apparatus 56 for the purpose of vulcanizing the neoprene and Hypalon or other materials used for the emission shields, and which require vulcanization or curing.
  • the apparatus 56 also activates the peroxide or other chemically cross-linking ingredients of the insulation, if the insulation is to be cross-linked.
  • Stations for applying the metal shield 84 and the outer plastic jacket 26 can be located beyond the apparatus 56; but in the illustration of FIG. 5 the cable is shown winding on a take-up reel 58, driven by suitable motor means (not shown) and if a metal shield and outer jacket are to be applied, this is done in a subsequent operation.
  • An electric power cable including in combination a conductor, a conductor shield surrounding the conductor, insulation around the conductor shield, the shield including an inner layer made of semiconducting material and the shield having an outer layer of material that prevents emission of electrons into the insulation from regions of high electrical stress in the semi-conducting inner layer.
  • the electric power cable described in claim I characterized by the material of the semiconducting shielding layer being made with electrically conducting material dispersed through the inner layer and with some non-uniformity in the dispersion of the conduct ing material through the other material of the inner layer of said shield, the said emission shielding layer serving to prevent electron emission into the insulation from regions of higher than average concentration of the conducting material in the semi-conducting layer.
  • the electric power cable described in claim I characterized by the insulation being polmeric material of low dielectric constant, and the emission shielding layer of the conductor shield being of material having a dielectric constant higher than that of the insulation.
  • the electric power cable described in claim 3 characterized by the emission shielding layer being made of flexible material and having a dielectric constant several times as great as that of the insulation.
  • the electric power cable described in claim 1 characterized by the emission shielding layer being made of material from the group consisting of neoprene, chlorosulfonated polyethylene and polyethylene filled with titanium dioxide compounds.
  • the electric power cable described in claim 9 characterized by the insulation being from the group consisting of polyethylene and cross-linked polyethylene.
  • the electric power cable described in claim I characterized by an insulation shield around the outside of the insulation including an emission shielding inner layer in contact with the insulation and a semiconducting outer layer, the emission shielding layer of said insulation shield being made of material that is free of electrical conducting particles, a metallic shield around the semi-conducting outer layer of the insulation shield. and a plastic outer jacket around the metallic shield for mechanical protection of the metallic shield.
  • the electric power cable described in claim 11 characterized by the insulation being an extruded insulation with contaminants and other imperfections limited in size to 0.003 inch in diameter.
  • the electric power cable described in claim 11 characterized by the insulation being of substantially greater radial thickness than the emission shielding layera.
  • the electric power cable described in claim 1 characterized by the insulation being made of material from the group comprising polyethylene and crosslinlted polyethylene, and the dielectric constant of the insulation being substantially less than that of the emission shielding layers.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Insulated Conductors (AREA)
  • Processes Specially Adapted For Manufacturing Cables (AREA)
  • Cable Accessories (AREA)
US478329A 1974-06-11 1974-06-11 High voltage solid extruded insulated power cables Expired - Lifetime US3885085A (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
US478329A US3885085A (en) 1974-06-11 1974-06-11 High voltage solid extruded insulated power cables
FR7504593A FR2273352A1 (pt) 1974-06-11 1975-02-14
IT48183/75A IT1040565B (it) 1974-06-11 1975-02-14 Apparecchiatura e procedimento pr produrre cavi isolati per al ta tensione
JP50019502A JPS51682A (en) 1974-06-11 1975-02-18 Denryokukeeburu sono seizohoho oyobi sochi
ES434861A ES434861A1 (es) 1974-06-11 1975-02-19 Procedimiento para la fabricacion de cables para energia e- lectrica.
GB1150475A GB1458493A (en) 1974-06-11 1975-03-19 Electric cables
DE19752517589 DE2517589A1 (de) 1974-06-11 1975-04-21 Hochspannungs-kraftkabel sowie verfahren und vorrichtung zur herstellung desselben
BR2579/75A BR7502579A (pt) 1974-06-11 1975-04-28 Cabo de energia eletrica aperfeicoado e aparelho e processo para sua producao
CA225,702A CA1031428A (en) 1974-06-11 1975-04-29 High voltage solid extruded insulated power cables
SE7506698A SE7506698L (sv) 1974-06-11 1975-06-11 Hogspenningskabel.
ES1975215398U ES215398Y (es) 1974-06-11 1975-09-24 Cable para energia electrica.
JP1983102863U JPS5955816U (ja) 1974-06-11 1983-07-04 電力ケ−ブル

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US478329A US3885085A (en) 1974-06-11 1974-06-11 High voltage solid extruded insulated power cables

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US478329A Expired - Lifetime US3885085A (en) 1974-06-11 1974-06-11 High voltage solid extruded insulated power cables

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US (1) US3885085A (pt)
JP (2) JPS51682A (pt)
BR (1) BR7502579A (pt)
CA (1) CA1031428A (pt)
DE (1) DE2517589A1 (pt)
ES (2) ES434861A1 (pt)
FR (1) FR2273352A1 (pt)
GB (1) GB1458493A (pt)
IT (1) IT1040565B (pt)
SE (1) SE7506698L (pt)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4008367A (en) * 1974-06-24 1977-02-15 Siemens Aktiengesellschaft Power cable with plastic insulation and an outer conducting layer
US4059724A (en) * 1975-03-22 1977-11-22 Homare Ide Shield wire
US4095039A (en) * 1976-04-16 1978-06-13 General Cable Corporation Power cable with improved filling compound
US4104480A (en) * 1976-11-05 1978-08-01 General Cable Corporation Semiconductive filling compound for power cable with improved properties
US4125741A (en) * 1977-09-30 1978-11-14 General Electric Company Differentially compressed, multi-layered, concentric cross lay stranded cable electrical conductor, and method of forming same
US4145567A (en) * 1977-06-06 1979-03-20 General Cable Corporation Solid dielectric cable resistant to electrochemical trees
US4247504A (en) * 1976-10-18 1981-01-27 Oy Nokia Ab Method of manufacturing plastic covered highvoltage cables
US4276251A (en) * 1977-01-17 1981-06-30 General Cable Corporation Power and control cables having flexible polyolefin insulation
US4342880A (en) * 1979-08-30 1982-08-03 Industrie Pirelli Societa Per Azioni Electric cable for medium voltage
US4360704A (en) * 1978-02-23 1982-11-23 Kabel-Und Metallwerke Gutehoffnungshutte Ag Moisture proof electrical cable
US4361723A (en) * 1981-03-16 1982-11-30 Harvey Hubbell Incorporated Insulated high voltage cables
US4487996A (en) * 1982-12-02 1984-12-11 Electric Power Research Institute, Inc. Shielded electrical cable
EP0212832A2 (en) * 1985-08-08 1987-03-04 PIRELLI GENERAL plc Electric cable jointing or terminating method
US5390386A (en) * 1993-06-01 1995-02-21 The D. S. Brown Company, Inc. Suspension bridge cable wrap and application method
US5750930A (en) * 1994-12-22 1998-05-12 The Whitaker Corporation Electrical cable for use in a medical surgery environment
US20040144471A1 (en) * 2001-02-03 2004-07-29 Harald Sikora Method for producing a cable
US20100218970A1 (en) * 2009-02-27 2010-09-02 Hitachi Cable, Ltd. Cable
CN103871660A (zh) * 2014-02-25 2014-06-18 安徽华成电缆有限公司 一种多芯扁型铜导体铠装引流电力电缆
US20140347158A1 (en) * 2013-05-24 2014-11-27 Keithley Instruments, Inc. Isolation transformer for use in isolated dc-to-dc switching power supply
CN105679424A (zh) * 2016-03-31 2016-06-15 宁国市明福线缆有限公司 一种高压电力电缆
US20180374607A1 (en) * 2017-06-27 2018-12-27 Halliburton Energy Services, Inc. Power and Communications Cable for Coiled Tubing Operations

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55131906A (en) * 1979-03-31 1980-10-14 Furukawa Electric Co Ltd Method of manufacturing crosslinked polyethylene power cable

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US3066180A (en) * 1957-04-06 1962-11-27 Asea Ab Coating for equalizing the potential gradient along the surface of an electric insulation
US3187071A (en) * 1962-07-18 1965-06-01 Gen Cable Corp Chemical bonding of rubber layers
US3412200A (en) * 1966-12-08 1968-11-19 Asea Ab High voltage cable with potential gradient equalization means
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US3792192A (en) * 1972-12-29 1974-02-12 Anaconda Co Electrical cable
US3792409A (en) * 1973-04-02 1974-02-12 Ransburg Corp Electrostatic hand gun cable
US3828115A (en) * 1973-07-27 1974-08-06 Kerite Co High voltage cable having high sic insulation layer between low sic insulation layers and terminal construction thereof

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Publication number Priority date Publication date Assignee Title
US3066180A (en) * 1957-04-06 1962-11-27 Asea Ab Coating for equalizing the potential gradient along the surface of an electric insulation
US3187071A (en) * 1962-07-18 1965-06-01 Gen Cable Corp Chemical bonding of rubber layers
US3412200A (en) * 1966-12-08 1968-11-19 Asea Ab High voltage cable with potential gradient equalization means
US3485939A (en) * 1968-04-24 1969-12-23 Okonite Co Electric cable with adhered polymeric insulation
US3666876A (en) * 1970-07-17 1972-05-30 Exxon Research Engineering Co Novel compositions with controlled electrical properties
US3792192A (en) * 1972-12-29 1974-02-12 Anaconda Co Electrical cable
US3792409A (en) * 1973-04-02 1974-02-12 Ransburg Corp Electrostatic hand gun cable
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Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4008367A (en) * 1974-06-24 1977-02-15 Siemens Aktiengesellschaft Power cable with plastic insulation and an outer conducting layer
US4059724A (en) * 1975-03-22 1977-11-22 Homare Ide Shield wire
US4095039A (en) * 1976-04-16 1978-06-13 General Cable Corporation Power cable with improved filling compound
US4247504A (en) * 1976-10-18 1981-01-27 Oy Nokia Ab Method of manufacturing plastic covered highvoltage cables
US4104480A (en) * 1976-11-05 1978-08-01 General Cable Corporation Semiconductive filling compound for power cable with improved properties
US4276251A (en) * 1977-01-17 1981-06-30 General Cable Corporation Power and control cables having flexible polyolefin insulation
US4145567A (en) * 1977-06-06 1979-03-20 General Cable Corporation Solid dielectric cable resistant to electrochemical trees
US4125741A (en) * 1977-09-30 1978-11-14 General Electric Company Differentially compressed, multi-layered, concentric cross lay stranded cable electrical conductor, and method of forming same
US4360704A (en) * 1978-02-23 1982-11-23 Kabel-Und Metallwerke Gutehoffnungshutte Ag Moisture proof electrical cable
US4342880A (en) * 1979-08-30 1982-08-03 Industrie Pirelli Societa Per Azioni Electric cable for medium voltage
US4361723A (en) * 1981-03-16 1982-11-30 Harvey Hubbell Incorporated Insulated high voltage cables
US4487996A (en) * 1982-12-02 1984-12-11 Electric Power Research Institute, Inc. Shielded electrical cable
EP0212832A2 (en) * 1985-08-08 1987-03-04 PIRELLI GENERAL plc Electric cable jointing or terminating method
EP0212832A3 (en) * 1985-08-08 1988-12-28 Pirelli General Plc Electric cables
US5390386A (en) * 1993-06-01 1995-02-21 The D. S. Brown Company, Inc. Suspension bridge cable wrap and application method
US5750930A (en) * 1994-12-22 1998-05-12 The Whitaker Corporation Electrical cable for use in a medical surgery environment
US20040144471A1 (en) * 2001-02-03 2004-07-29 Harald Sikora Method for producing a cable
US20100218970A1 (en) * 2009-02-27 2010-09-02 Hitachi Cable, Ltd. Cable
US8530745B2 (en) * 2009-02-27 2013-09-10 Hitachi Cable, Ltd. Cable including elemental wires with different angles
US9478351B2 (en) * 2013-05-24 2016-10-25 Keithley Instruments, Inc. Isolation transformer for use in isolated DC-to-DC switching power supply
US20140347158A1 (en) * 2013-05-24 2014-11-27 Keithley Instruments, Inc. Isolation transformer for use in isolated dc-to-dc switching power supply
CN103871660A (zh) * 2014-02-25 2014-06-18 安徽华成电缆有限公司 一种多芯扁型铜导体铠装引流电力电缆
CN105679424A (zh) * 2016-03-31 2016-06-15 宁国市明福线缆有限公司 一种高压电力电缆
CN105679424B (zh) * 2016-03-31 2017-04-26 安徽明福电缆有限公司 一种高压电力电缆
US20180374607A1 (en) * 2017-06-27 2018-12-27 Halliburton Energy Services, Inc. Power and Communications Cable for Coiled Tubing Operations
US10971284B2 (en) * 2017-06-27 2021-04-06 Halliburton Energy Services, Inc. Power and communications cable for coiled tubing operations
US11639662B2 (en) 2017-06-27 2023-05-02 Halliburton Energy Services, Inc. Power and communications cable for coiled tubing operations

Also Published As

Publication number Publication date
FR2273352A1 (pt) 1975-12-26
DE2517589A1 (de) 1976-01-02
SE7506698L (sv) 1975-12-12
JPS5955816U (ja) 1984-04-12
CA1031428A (en) 1978-05-16
GB1458493A (en) 1976-12-15
ES215398U (es) 1976-07-16
BR7502579A (pt) 1976-12-21
ES434861A1 (es) 1977-04-01
IT1040565B (it) 1979-12-20
ES215398Y (es) 1976-12-01
JPS51682A (en) 1976-01-06

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