AU670552B2 - An improved composite overhead electric and optical conductor - Google Patents

An improved composite overhead electric and optical conductor Download PDF

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Publication number
AU670552B2
AU670552B2 AU30066/92A AU3006692A AU670552B2 AU 670552 B2 AU670552 B2 AU 670552B2 AU 30066/92 A AU30066/92 A AU 30066/92A AU 3006692 A AU3006692 A AU 3006692A AU 670552 B2 AU670552 B2 AU 670552B2
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AU
Australia
Prior art keywords
optical
optical fibre
stack
overhead electric
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.)
Ceased
Application number
AU30066/92A
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AU3006692A (en
Inventor
Christopher Simon Pegge
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.)
Balfour Beatty PLC
Original Assignee
BICC PLC
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 BICC PLC filed Critical BICC PLC
Publication of AU3006692A publication Critical patent/AU3006692A/en
Application granted granted Critical
Publication of AU670552B2 publication Critical patent/AU670552B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4415—Cables for special applications
    • G02B6/4416—Heterogeneous cables
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4403—Optical cables with ribbon structure
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/441—Optical cables built up from sub-bundles
    • G02B6/4411—Matrix structure
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4415—Cables for special applications
    • G02B6/4416—Heterogeneous cables
    • G02B6/4422—Heterogeneous cables of the overhead type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4429—Means specially adapted for strengthening or protecting the cables
    • G02B6/443—Protective covering
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4429—Means specially adapted for strengthening or protecting the cables
    • G02B6/44384—Means specially adapted for strengthening or protecting the cables the means comprising water blocking or hydrophobic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
    • H01B5/08—Several wires or the like stranded in the form of a rope
    • H01B5/10—Several wires or the like stranded in the form of a rope stranded around a space, insulating material, or dissimilar conducting material
    • H01B5/108—Several wires or the like stranded in the form of a rope stranded around a space, insulating material, or dissimilar conducting material stranded around communication or control conductors

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Communication Cables (AREA)

Description

AUSTRALIA
PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): BICC Public Limited Company ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.
INVENTION TITLE: An improved composite overhead electric and optical conductor *6 The following statement is a full description of of performing it known to me/us:this invention, including the best method la.
This invention relates to overhead electric conductors of the kind which comprise one or more than one layer of helically wound elongate elements of electrically conductive metal or metal alloy and which are adapted to be freely suspended in long lengths from towers, pylons or other upstanding supports mutually spaced along the route of an overhead electric transmission or distribution system.
The invention is particularly concerned with overhead electric conductors of this kind which include at least one flexible optical guide consisting of or comprising at least one optical fibre for transmission of the ultra-violet, visible and infra-red regions of the electro-magnetic spectrum, which regions, for ~convenience, will hereinafter all be included in the 2. generic term "light". One composite overhead electric .optical conductor of this kind is the subject of our British Patent No: 1598438.
It has become the general practice to employ a composite overhead electric and optical conductor of the aforesaid kind as an earth conductor of an overhead electric transmission or distribution system and, because a composite overhead electric and optical conductor of this kind may be manufactured to have the 00.
swane or approximately the same properties of sag and tension as those of conventional overhead earth 2.
conductors of substantially the same overall diameter, it can be used to replace a conventional overhead earth conductor of an existing overhead electric transmission or distribution system thereby to provide a relatively inexpensive communication link between stations, substations and other locations along the route of the system and/or an optical communication system between populated areas between which the overhead electric transmission or distribution system extends.
With the rapid growth of communication services required, it is recognised that a composite overhead electric and optical conductor of the aforesaid kind of necessity will have to incorporate a greater number of optical fibres for the transmission of light signals than has hitherto been provided. Whilst increasing the number of optical fibres incorporated in an overhead electric conduc or is not in itself a problem, it is desirable that an increase in optical fibre count of a composite overhead electric and optical conductor is achieved without effecting a substantial increase in the overall diameter, and hence weight, of the conductor.
This is especially important where a composite overhead electric and optical conductor having a high optical fibre count is to be used to replace an overhead earth conductor of an existing overhead transmission or distribution system if the substantial expense of upgrading the towers, pylons or other upstanding supports of the system to accommodate a larger and heavier earth conductor is to be avoided.
It is an object of the present invention to provide an improved composite overhead electric and optical conductor which can have a greater number of optical fibres than and substantially the same overall diameter as composite overhead electric and optical conductors hitherto proposed and used.
According to the invention, the improved composite overhead electric and optical conductor comprises a circumferentially rigid central core of metal or metal alloy having throughout its length a bore in which a flexible optical guide is substantially tightly disposed and, surrounding the central metal core, at least one layer of helically wound elongate elements of electrically conductive metal or metal alloy, which flexible optical guide comprises a plurality of optical fibre ribbons arranged face-to-face to form a stack, each optical fibre ribbon comprising at least two optical fibres arranged side-by-side with their axes lying in a common plane and wholly encapsulated in a cured resin, an overall sheath of plastics material surrounding the stack of optical fibre ribbons and, filling the interstices between the stack *0 of optical fibre ribbons and the sheath, a cured resin.
ver-head--e-e-l-e-r-a-an-opt-ie a-l-oa on -imprved-eem-apa- teeverhead--ele-te-a-d-opt-Gal-eondutot-i -eapable-e Q:\OP'R\GaM0066.C -9/5/96 3A The invention also provides a composite overhead electric and optical conductor comprising a circumferentially rigid central core of metal or metal alloy having throughout its length a bore in which two or more flexible optical guides are helically laid up together and substantially tightly disposed and, surrounding the central metal core, at least one layer of helically wound elongate elements of electrically conductive metal or metal alloy, wherein each flexible optical guide comprises a plurality of optical fibre ribbons arranged face-to-face to form a stack, each optical fibre ribbon comprising at least two optical fibres arranged sideby-side with their axes lying in a common plane and wholly encapsulated in a cured resin, an overall sheath of plastics material surrounding the stack of optical fibre ribbons and, filling the 10 interstices between the stack of optical fibre ribbons and the sheath, a cured resin, and wherein the interstices between the assembled optical guides are filled with a water-impermeable medium or accommodate water-swellable elements throughout the length of the composite Sconductor.
Preferably, to ensure that the improved composite overhead electric and optical conductor is capable of t* 0 Ag
A
SeT R 11b withstanding temperatures of up to approximately 2500C with negligible risk of degradation of the optical fibres of the optical fibre ribbons due to heat exposure, the cured resin within which the stack of optical fibre ribbons is wholly encapsulated is a photocured acrylate resin and the overall sheath is of crosslinked polyethylene. Where the improved composite conductor is required to withstand temperatures substantially higher than 250 0 C, e.g. at least 300 0
C,
preferably the overall sheath is made of a high temperature resistant thermoplastics material, e.g. a fluoropolymer; preferably, in these circumstances a layer of thermal insulating material underlies and/or overlies the overall plastics sheath to limit further risk of degradation of the optical fibres of the optical fibre ribbons due to heat exposure. Suitable thermal insulating materials include silicone elastomers.
Each optical fibre ribbon of the stack may comprise the same number of optical fibres as the other optical fibre ribbon or each of the other optical fibre ribbons of the stack but, preferably, with a view to
S
ensuring that the imaginary cylinder of circular crosso.
section circumscribing the stack has as small a diameter as possible, the outermost optical fibre ribbons of a stack comprising three or more optical fibre ribbons each comprises fewer optical fibres than the or each optical fibre ribbon sandwiched therebetween. For example. a flexible opticl guide of the improved composite cpnrtitor of the present invention comprising twelve optical fibres has a stack comprising two optical fibre ribbons, each comprising four optical fibres, sandwiched between two optical fibre ribbons each comprising two optical fibres.
Each optical fibre of each optical fibre ribbon of the stack preferably has a coating of a colour readily distinguishable from the colour of the coating of the or each other of the optical fibres of the optical fibre ribbon.
Preferably, each optical fibre of each optical fibre ribbon of the improved composite overhead electric and optical conductor has been proof-tested to ensure that it is capable of withstanding any tensile force to which it is likely to be subjected whilst the composite conductor is in service and, in general, optical fibres currently available from Optical Fibres, Deeside, Clwyd are wholly suitable for use in the improved composite conductor, but where the improved composite conductor is to be used in an overhead electric transmission or distribution system where it is likely to be subjected ,oo to exceptionally severe conditions whilst it is in service, specially manufactured strain-resistant optical fibres may be employed.
With a view to reducing risk of buckling of the flexible optical guide of the improved composite conductor before the flexible optical guide is tightly disposed in the bore of the circumferentially rigid tubular central core, the flexible optical guide may incorporate two or more elongate elements of tensile resistant material, each preferably a pultruded elongate element of resin bonded fibres of non-optical glass or other non-metallic tensile resistant material. Such tensile resistant elongate elements may be wholly encapsulated in the cured resin in which the stack of optical fibre ribbons is encapsulated and/or at least one optical fibre of each of two or more of the optical fibre ribbons of the stack may be replaced by a tensile resistant elongate element. In all cases, the tensile resistant elongate elements will be evenly distributed within the flexible optical guide of the improved composite conductor.
The circumferentially rigid central tubular metal core preferably is a tube of metal or metal alloy, which tube may be formed by extrusion or may have a welded seam, but in some circumstances it may be formed from an extrudate of approximately C-shaped cross-section, the limbs of the extrudate being closed to form a seamed tube, By way of example, a flexible optical guide of the improved composite conductor having a stack of four optical fibre ribbons arranged face-to-face, the intermediate optical fibre ribbons each comprising four 7.
optical fibres and the end optical fibre ribbons each comprising two optical fibres, has an overall diameter which is less than half that of a comparable flexible optical guide of composite conductors hitherto proposed and used, as a consequence of which the improved composite conductor has an cverall diameter which can be substantially less than that of most known comparable composite conductors.
Furthermore, an improved composite conductor having an exceptionally high optical fibre count, e.g.
forty-eight optical fibres, can comprise two or more flexible optical guides of the improved composite conductor hereinbefore described helically laid up together and substantially tightly disposed in the bore of a circumferentially rigid tubular central core of metal or metal alloy, the interstices between the assembled optical guides being filled with a waterimpermeable medium or accommodating water-swellable elements throughout the length of the composite conductor. For example, an improved composite conductor of the present invention comprising four flexible S'.i optical guides helically laid up together, each having a stack of optical fibre ribbons totalling twelve optical fibres, will have an overall diameter no greater than that of composite overhead conductors hitherto proposed and used having only twenty-four optical fibres.
The invention is further illustrated by a description, by way of example, of a preferred composite overhead electric and optical conductor with reference to the accompanying drawing which shows a transverse cross-sectional view of the conductor, drawn on an enlarged scale.
Referring to the drawing, the preferred composite overhead electric and optical conductor comprises a circumferentially rigid central aluminium tube 2 which has tightly disposed in its bore throughout its length a flexible optical guide 1 and, surrounding the aluminium tube, a layer 3 of helically wound steel wires 4. The flexible optical guide 1 comprises a stack 5 of four optical fibre ribbons 6, 7 arranged face-to-face and surrounded by an overall sheath 10 of cross-linked 4*.
polyethylene. The stack 5 comprises two optical fibre g ribbons 6, each consisting of four optical fibres 8 arranged side-by-side with their axes lying in a common plane and wholly encapsulated in photo-cured acrylic resin 9, sandwiched between two optical fibre ribbons 7, each consisting of two optical fibres 8 arranged sideby-side with their axes lying in a common plane and wholly encapsulated in photo-cured acrylic resin 9. The interstices between the stack 5 of optical fibre ribbons 6, 7 and the overall sheath 10 are filled with photocured acrylic resin 11.
9.
The preferred composite overhead electric and optical conductor illustrated in the accompanying drawing and incorporating twelve optical fibres is of substantially the same overall diameter as composite overhead electric and optical conductors hitherto proposed and used incorporating only a few optical fibres.

Claims (7)

1. A composite overhead electric and optical conductor comprising a circumferentially rigid central core of metal or metal alloy having throughout its length a bore in which a flexible optical guide is substantially tightly disposed and, surrounding the central metal core, at least one layer of helically wound elongate elements 'f electrically conductive metal or metal alloy, wherein the flexible optical guide comprises a plurality of optical fibre ribbons arranged face-to-face to form a stack, each optical fibre ribbon comprising at least two optical fibres arranged side-by- side with their axes lying in a common plane and wholly encapsulated in a cured resin, an overall sheath of plastics material surrounding the stack of optical fibre ribbons and, filling the interstices between the stack of optical fibre ribbons and the sheath, a cured resin.
2. A composite overhead electric and optical conductor as claimed in Claim 1, wherein the stack ,*..comprises three or more optical fibre ribbons and wherein the outermost optical fibre ribbons of the stack each comprises fewer optical fibres than the or each optical fibre ribbon sandwiched therebetween.
3. A composite overhead electric and optical conductor as claimed in Claim 2, wherein the stack comprises two optical fibre ribbons, each comprising four optical fibres, sandwiched between two optical fibre ribbons each comprising two optical fibres.
11. 4. A composite overhead electric and optical conductor as claimed in any one of the preceding Claims, wherein the flexible optical guide incorporates two or more elongate elements of tensile resistant material evenly distributed within the guide. A composite overhead electric and optical conductor as claimed in Claim 4, wherei the tensile resistant elongate elements are wholly encapsulated in the cured resin in which the stack of optical fibre ribbons is encapsulated and/or at least one optical fibre of each of two or more of the optical fibre ribbons of the stack is replaced by a tensile resistant elongate element. 6. A composite overhead electric and optical conductor as claimed in Claims 4 or 5, wherein each i tensile resistant elongate element is a pultrude' elongate element of resin bonded fibres of non-optical glass or other non-metallic tensile resistant material. 7. A composite overhead electric and optical conductor as claimed in any one of the preceding Claims, wherein the cured resin within which the stack of optical fibre ribbons is wholly encapsulated is a photo- cured acrylic resin and the overall sheath is of cross- linked polyethylene. 8. A composit overhead electric and optical conductor as claimed in any one of Claims 1 to 6, wherein the cured resin within which the stack of
12. optical fibre ribbons is wholly encapsulated is a photo- cured acrylic resin and the overall sheath is of a fluoropolymer. 9. A composite overhead electric and optical conductor as claimed in Claim 8, wherein a layer of thermal insulating material underlies and/or overlies the overall sheath. A composite overhead electric and optical conductor as claimed in Claim 9, wherein the thermal insulating material of the or each said layer is a silicone elastomer. 11, A composite overhead electric and optical conductor as claimed in any one of the preceding Claims, wherein each optical fibre of each optical fibre ribbon of the stack has a coating of a colour readily distinguishable from the colour of the coating of the or each other of the optical fibres of the optical fibre ribbon. 12. A composite overhead electric and optical conductor as claimed in any one of the preceding Claims, wherein each optical fibre has been proof-tested. e° 4
13. A composite overhead electric and optical i*0*. conductor as claimed in any one of the preceding Claims, wherein the circumferentially rigid central core of metal or metal alloy is an extruded tube or is a tube having a welded seam. 1:3.
14. A composite overhead electric and optical conductor comprising a circumferentially rigid central core of metal or metal alloy having throughout its length a bore in which two or more flexible optical guides are helically laid up together and substantially tightly disposed and, surrounding the central metal core, at least one layer of helically wound elongate elements of electrically conductive metal or metal alloy, wherein each flexible optical guide comprises a plurality of optical fibre ribbons arranged face-to-face to form a stack, each optical fibre ribbon comprising at least two optical fibres arranged side-by-side with their axes lying in a common plane and wholly encapsulated in a cured resin, an overall sheath of plastics material surrounding the stack of optical fibre ribbons and, filling the interstices between the stack of optical fibre ribbons and the sheath, a cured resin, and wherein the interstices between the assembled optical guides are filled with a water-impermeable medium or accommodate water-swellable elements throughout the length of the composite conductor. 15 A composite overhead electric and optical conductor substantially as hereinbefore described with reference to and as shown in the accompanying drawing. a 1--4---he-st-ep--f-eatu-res--oompoei-t-i-ons-a-nd-oompound disclosed herein or referred to or indi ed-i' the specification and/or ol.ims-o-fEiis application, individual.--or:Tolectively, and any and all combinations ay--e---more-of-sad-Bteps -or-e ature s- DATED this TENTH day of DECEMBER 1992 BICC Public Limited Company Rby DAVIES COLLISON CAVE SPatent Attorneys for the applicant(s) ABSTRACT AN IMPROVED COMPOSITE OVERHEAD ELECTRIC AND OPTICAL CONDUCTOR A composite overhead electric and optical conductor comprises a circumferentially rigid central metal tube 2 having tightly disposed in its bore throughout its length a flexible optical guide 1 and, surrounding the metal tube, a layer 3 of helically wound metal wires 4. The flexible optical guide 1 comprises a stack 5 of optical fibre ribbons 6, 7 arranged face-to- face. Each optical fibre ribbon 6, 7 comprises two or more optical fibres 8 arranged side-by-side with their axes lying in a common plane and wholly encapsulated in a cured resin 9, the outermost ribbons 7 having fewer optical fibres than the ribbons sandwiched therebetween. An overall plastics sheath 10 surrounds the stack 5 and the interstices between the stack and the sheath are *i. filled with a cured resin 11. a S. S S S
AU30066/92A 1991-12-11 1992-12-10 An improved composite overhead electric and optical conductor Ceased AU670552B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9126232 1991-12-11
GB919126232A GB9126232D0 (en) 1991-12-11 1991-12-11 An improved composite overhead electric and optical conductor

Publications (2)

Publication Number Publication Date
AU3006692A AU3006692A (en) 1993-06-17
AU670552B2 true AU670552B2 (en) 1996-07-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
AU30066/92A Ceased AU670552B2 (en) 1991-12-11 1992-12-10 An improved composite overhead electric and optical conductor

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AU (1) AU670552B2 (en)
GB (2) GB9126232D0 (en)
NZ (1) NZ245430A (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6621966B2 (en) * 1999-03-31 2003-09-16 Corning Cable Systems Llc Fiber optic cable with profiled group of optical fibers
US6487348B1 (en) * 1999-11-12 2002-11-26 Fitel Usa Corp. Variable fiber count optical fiber cable core
US6421487B1 (en) * 2000-05-03 2002-07-16 Alcatel Reinforced buffered fiber optic ribbon cable
FR2941812A1 (en) * 2009-02-03 2010-08-06 Nexans ELECTRICAL TRANSMISSION CABLE WITH HIGH VOLTAGE.
EP2845043A4 (en) 2012-05-02 2015-12-16 Fujikura Ltd Round and small diameter optical cables with a ribbon-like optical fiber structure

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1598438A (en) * 1977-05-13 1981-09-23 Bicc Ltd Overhead electric transmission systems
EP0155184A2 (en) * 1984-03-14 1985-09-18 BICC Public Limited Company An improved flexible elongate body

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1598438A (en) * 1977-05-13 1981-09-23 Bicc Ltd Overhead electric transmission systems
EP0155184A2 (en) * 1984-03-14 1985-09-18 BICC Public Limited Company An improved flexible elongate body

Also Published As

Publication number Publication date
NZ245430A (en) 1996-03-26
AU3006692A (en) 1993-06-17
GB9126232D0 (en) 1992-02-12
GB9225800D0 (en) 1993-02-03
GB2262357B (en) 1995-01-18
GB2262357A (en) 1993-06-16

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