GB2262359A - Composite overhead electric and optical fibre conductor - Google Patents
Composite overhead electric and optical fibre conductor Download PDFInfo
- Publication number
- GB2262359A GB2262359A GB9225814A GB9225814A GB2262359A GB 2262359 A GB2262359 A GB 2262359A GB 9225814 A GB9225814 A GB 9225814A GB 9225814 A GB9225814 A GB 9225814A GB 2262359 A GB2262359 A GB 2262359A
- Authority
- GB
- United Kingdom
- Prior art keywords
- optical
- fibres
- overhead electric
- conductor
- metal
- 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.)
- Granted
Links
- 239000004020 conductor Substances 0.000 title claims abstract description 53
- 239000002131 composite material Substances 0.000 title claims abstract description 42
- 239000013307 optical fiber Substances 0.000 title claims abstract description 11
- 230000003287 optical effect Effects 0.000 claims abstract description 86
- 229910052751 metal Inorganic materials 0.000 claims abstract description 18
- 239000002184 metal Substances 0.000 claims abstract description 18
- 229910001092 metal group alloy Inorganic materials 0.000 claims abstract description 13
- 239000004033 plastic Substances 0.000 claims abstract description 10
- 229920003023 plastic Polymers 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 9
- 229920005989 resin Polymers 0.000 claims abstract description 9
- 239000011347 resin Substances 0.000 claims abstract description 9
- 239000011248 coating agent Substances 0.000 claims abstract description 8
- 238000000576 coating method Methods 0.000 claims abstract description 8
- 239000011810 insulating material Substances 0.000 claims description 4
- 229920002050 silicone resin Polymers 0.000 claims description 4
- 229920002313 fluoropolymer Polymers 0.000 claims description 2
- 239000004811 fluoropolymer Substances 0.000 claims description 2
- 229920002379 silicone rubber Polymers 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 abstract description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 3
- 229910000831 Steel Inorganic materials 0.000 abstract description 2
- 239000010959 steel Substances 0.000 abstract description 2
- 229910000838 Al alloy Inorganic materials 0.000 abstract 1
- 229920001296 polysiloxane Polymers 0.000 abstract 1
- 230000005540 biological transmission Effects 0.000 description 8
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
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
- G02B6/4429—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
-
- 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
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Communication Cables (AREA)
Abstract
A composite overhead electric and optical conductor comprises a central metal, e.g. aluminium, or metal alloy tube 2 having tightly disposed in its bore throughout its length a flexible optical guide 1 and, surrounding the tube, a layer 3 of helically wound electrical conductors e.g. steel wires 4. The flexible optical guide 1 comprises several separate optical fibres 5, an overall sheath 7 of, e.g. a high modulus, low thermal expansion, plastics material surrounding the optical fibres and, filling the interstices between the separate optical fibres and between the fibres and the sheath, a low modulus, cured, e.g. silicone, resin 6 having rubber-like properties. Preferably, each optical fibre has a coating of a colour readily distinguishable from the colour of the coating of each of the other optical fibres. The interstices may be filled with a water-impermeable medium or accommodate water-swellable elements. <IMAGE>
Description
AN IMPROVED COMPOSITE OVERHEAD ELECTRIC
AND OPTICAL CONDUCTOR
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 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 same or approximately the same properties of sag and tension as those of conventional overhead earth 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 conductor 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 separate optical fibres, an overall sheath of plastics material surrounding the optical fibres and, filling the interstices between the separate optical fibres and between the fibres and the sheath, a low modulus cured resin.
The separate optical fibres preferably are randomly disposed within the low modulus cured resin, each optical fibre having a coating of a colour readily distinguishable from the colour of the coating of the or each other of the optical fibres.
Preferably, to ensure that the improved composite overhead electric and optical conductor is capable of withstanding temperatures down to -1000C and up to approximately 2500C with negligible risk of degradation of the helically wound optical fibres, the low modulus cured resin is a cured silicone resin having rubber-like properties and the overall sheath is of a high modulus, low thermal expansion plastics material. Where the improved composite conductor is required to withstand temperatures substantially higher than 25O0C, e.g. at least 3000C, preferably the overall sheath is made of a high temperature resistant thermoplastics material, e.g.
a fluoropolymer; preferably, also, 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 due to heat exposure. Suitable thermal insulating materials include silicone elastomers.
Preferably, each optical fibre 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 to exceptionally severe conditions whilst it is in service, specially manufactured strain-resistant optical fibres may be employed.
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 transverse crosssection, 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 twelve 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 overall 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 ore of a circumferentially rigid tubular central core of metal or metal alloy, the interstices between the assembled flexible optical guides being filled with a water-impermeable medium or accommodating waterswellable elements throughout the length of the composite conductor. For example, an improved composite conductor of the present invention comprising four flexible optical guides helically laid up together, each comprising twelve separate 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 having tightly disposed within 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 twelve flexible optical fibres 5, an overall sheath 7 of a high modulus low thermal expansion plastics material surrounding the optical fibres and, filling the interstices between the separate optical fibres and between the fibres and the sheath, a cured silicone resin 6 having rubber-like properties. The separate optical fibres 5 are randomly disposed within the cured silicone resin 6 and each optical fibre has a coating of a colour readily distinguishable from the colour of the coating of each of the other of the optical fibres.
The preferred composite overhead electric and optical conductor illustrated in the accompanying drawing and incorporating twelve separate optical fibres can have the same overall diameter as composite overhead electric and optical conductors hitherto proposed and used incorporating only a few optical fibres.
Claims (10)
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 of electrically conductive metal or metal alloy, wherein the flexible optical guide comprises a plurality of separate optical fibres, an overall sheath of plastics material surrounding the optical fibres and, filling the interstices between the separate optical fibres and between the fibres and the sheath, a low modulus cured resin.
2. 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 of electrically conductive metal or metal alloy, wherein the flexible optical guide comprises a plurality of separate optical fibres, an overall sheath of plastics material surrounding the optical fibres and a low modulus cured resin filling the interstices between the separate optical fibres and between the fibres and the sheath, the separate optical fibres being randomly disposed within the low modulus cured resin and each optical fibre having a coating of a colour readily distinguishable from the colour of the coating of the or each other of the optical fibres.
3. A composite overhead electric and optical conductor as claimed in Claim 1 or 2, wherein the low modulus cured resin is a cured silicone resin having rubber-like properties and the overall sheath is of a high modulus, low thermal expansion plastics material.
4. A composite overhead electric and optical conductor as claimed in Claim 3, wherein the properties and the overall sheath is of a fluoropolymer.
5. A composite overhead electric and optical conductor as claimed in Claim 4, wherein a layer of thermal insulating material underlies and/overlies the overall plastics sheath.
6. A composite overhead electric and optical conductor as claimed in Claim 5, wherein the thermal insulating material is a silicone elastomer.
7. A composite overhead electric and optical conductor as claimed in any one of the preceding Claims, wherein each optical fibre has been proof-tested.
8. A composite overhead electric and optical 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 a tube having a welded seam.
9. 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 separate optical fibres, an overall sheath of plastics material surrounding the optical fibres and, filling the interstices between the separate optical fibres and between the fibres and the sheath a low modulus cured resin, and wherein the interstices between the assembled flexible optical guides are filled with a water-impermeable medium or accommodate water-swellable elements throughout the length of the composite conductor.
10. A composite overhead electric and optical conductor substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB919126251A GB9126251D0 (en) | 1991-12-11 | 1991-12-11 | An improved composite overhead electric and optical conductor |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9225814D0 GB9225814D0 (en) | 1993-02-03 |
| GB2262359A true GB2262359A (en) | 1993-06-16 |
| GB2262359B GB2262359B (en) | 1995-02-01 |
Family
ID=10706031
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB919126251A Pending GB9126251D0 (en) | 1991-12-11 | 1991-12-11 | An improved composite overhead electric and optical conductor |
| GB9225814A Expired - Fee Related GB2262359B (en) | 1991-12-11 | 1992-12-10 | Composite overhead electric and optical fibre conductor |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB919126251A Pending GB9126251D0 (en) | 1991-12-11 | 1991-12-11 | An improved composite overhead electric and optical conductor |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU3006792A (en) |
| GB (2) | GB9126251D0 (en) |
| NZ (1) | NZ245431A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0969302A1 (en) * | 1998-06-30 | 2000-01-05 | Pirelli Cable Corporation | Composite cable for access networks |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2010528A (en) * | 1977-12-16 | 1979-06-27 | Post Office | Underwater Cable |
| GB1580863A (en) * | 1976-05-21 | 1980-12-03 | Cables De Lyon Geoffroy Delore | Optical fibre cable and a method of manufacture |
| GB1598438A (en) * | 1977-05-13 | 1981-09-23 | Bicc Ltd | Overhead electric transmission systems |
| GB2085187A (en) * | 1980-10-02 | 1982-04-21 | Pirelli Cavi Spa | Overhead cables and earth conductors including optical fibres |
| GB2116746A (en) * | 1982-03-18 | 1983-09-28 | Bicc Plc | An improved flexible stranded body |
| US4840454A (en) * | 1986-09-02 | 1989-06-20 | Siemens Aktiengesellschat | Optical cable and method of manufacturing |
| US4906067A (en) * | 1988-03-31 | 1990-03-06 | Siemens Aktiengesellschaft | Optical cable comprising a plurality of bundle elements |
-
1991
- 1991-12-11 GB GB919126251A patent/GB9126251D0/en active Pending
-
1992
- 1992-12-10 NZ NZ245431A patent/NZ245431A/en unknown
- 1992-12-10 GB GB9225814A patent/GB2262359B/en not_active Expired - Fee Related
- 1992-12-10 AU AU30067/92A patent/AU3006792A/en not_active Abandoned
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1580863A (en) * | 1976-05-21 | 1980-12-03 | Cables De Lyon Geoffroy Delore | Optical fibre cable and a method of manufacture |
| GB1598438A (en) * | 1977-05-13 | 1981-09-23 | Bicc Ltd | Overhead electric transmission systems |
| GB2010528A (en) * | 1977-12-16 | 1979-06-27 | Post Office | Underwater Cable |
| GB2085187A (en) * | 1980-10-02 | 1982-04-21 | Pirelli Cavi Spa | Overhead cables and earth conductors including optical fibres |
| GB2116746A (en) * | 1982-03-18 | 1983-09-28 | Bicc Plc | An improved flexible stranded body |
| US4840454A (en) * | 1986-09-02 | 1989-06-20 | Siemens Aktiengesellschat | Optical cable and method of manufacturing |
| US4906067A (en) * | 1988-03-31 | 1990-03-06 | Siemens Aktiengesellschaft | Optical cable comprising a plurality of bundle elements |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0969302A1 (en) * | 1998-06-30 | 2000-01-05 | Pirelli Cable Corporation | Composite cable for access networks |
| US6195487B1 (en) | 1998-06-30 | 2001-02-27 | Pirelli Cable Corporation | Composite cable for access networks |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9126251D0 (en) | 1992-02-12 |
| NZ245431A (en) | 1996-03-26 |
| AU3006792A (en) | 1993-06-17 |
| GB2262359B (en) | 1995-02-01 |
| GB9225814D0 (en) | 1993-02-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19991210 |