GB2104304A - An improved overhead electric transmission or distribution system - Google Patents
An improved overhead electric transmission or distribution system Download PDFInfo
- Publication number
- GB2104304A GB2104304A GB08217322A GB8217322A GB2104304A GB 2104304 A GB2104304 A GB 2104304A GB 08217322 A GB08217322 A GB 08217322A GB 8217322 A GB8217322 A GB 8217322A GB 2104304 A GB2104304 A GB 2104304A
- Authority
- GB
- United Kingdom
- Prior art keywords
- stranded conductor
- conductor
- tower
- stranded
- overhead
- 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
- 230000005540 biological transmission Effects 0.000 title claims description 25
- 239000004020 conductor Substances 0.000 claims abstract description 99
- 239000013307 optical fiber Substances 0.000 claims abstract description 20
- 239000000725 suspension Substances 0.000 claims abstract description 12
- 230000003287 optical effect Effects 0.000 claims description 13
- 239000003989 dielectric material Substances 0.000 claims description 5
- 238000009434 installation Methods 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000007665 sagging Methods 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
- G02B6/4415—Cables for special applications
- G02B6/4416—Heterogeneous cables
- G02B6/4422—Heterogeneous cables of the overhead type
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G7/00—Overhead installations of electric lines or cables
- H02G7/05—Suspension arrangements or devices for electric cables or lines
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Suspension Of Electric Lines Or Cables (AREA)
Abstract
Risk of fracture of an optical fibre loosely housed in an elongate compartment extending throughout the length of an overhead stranded conductor 1 when the conductor is subjected to a tensile load greater than that which the optical fibre is designed to withstand is reduced by supporting the stranded conductor from each of two opposite sides of a tower 2 by suspension means 3 incorporating a weak link 4 designed to fracture at a tensile load less than that which the optical fibre can withstand. An excess length 6 of the stranded conductor extends between fittings 5 at which the suspension means 3 are secured to the conductor 1 and, where the stranded conductor is an earth conductor, is detachably secured to the tower at spaced positions along its length by releasable clips 7. When the load on conductor 1 increases, a weak link 4 will fracture and the excess length 6 of stranded conductor will be detached from the tower to reduce the load on the conductor and thereby reduce risk of optical fibre fracture. <IMAGE>
Description
SPECIFICATION
An improved overhead electric transmission or distribution system
This invention relates to an overhead electric transmission or distribution system in which at least one overhead stranded electric conductor is freely supported in long lengths from towers, pylons or other upstanding supports spaced along the system, all such supports, for convenience, hereinafter being included in the generic term "tower".
In the Complete Specification of our British
Patent No. 1598438 there is described and claimed, for use in an overhead electric transmission or distribution system, an overhead stranded electric conductor which includes at least one optical waveguide for use in the communications field adapted for transmission of light and which comprises at least one layer of helically wound bare elongate elements of metal or metal alloy, at least one elongate compartment within and extending throughout the length of the stranded conductor and, loosely housed in the elongate compartment or at least one of the elongate compartments, at least one separate optical fibre and/or at least one optical bundle.
By the expression "optical bundle" is meant a group of optical fibres or a group of fibres including at least one optical fibre and including at least one non-optical reinforcing fibre or other reinforcing elongate member.
An overhead stranded electric conductor as described and claimed in the aforesaid patent will hereinafter be referred to as an "overhead stranded electric conductor of the kind described".
When an overhead stranded electric conductor of the kind described supported in an overhead electric transmission or distribution system vibrates, oscillates or is otherwise flexed, as may, for example, occur when the conductor is subjected to winds, by virtue of being housed loosely in the elongate compartment of the conductor, limited relative movement between the or each separate optical fibre and the stranded conductor and or between the or each optical bundle and the stranded conductor can take place, thereby substantially reducing the risk of optical fibre fracture.Limited relative movement between the or each separate optical fibre and the stranded conductor and/or between the or each optical bundle and the stranded conductor can also occur when the overhead stranded conductor is subjected to a change in tensile load during and after its installation due to forces imposed on it by winches and brakes, etc., which are used in tensioning the stranded conductor to obtain a predetermined sagging condition; after installation, changes in tensile load in the overhead stranded conductor can also occur due to changes in external loading and in temperature.Limited relative movement between the or each separate optical fibre and the stranded conductor and/or between the or each optical bundle and the stranded conductor can also occur whilst the overhead stranded conductor is in service and creep gives rise to non-elastic extension of the stranded conductor.
It is an object of the present invention to provide an improved overhead electric transmission or distribution system including at least one overhead stranded electric conductor of the kind described, wherein, in the event that the overhead stranded conductor is subjected to a tensile load greater than that which the or each optical fibre and/or optical bundle is designed to withstand, risk of optical fibre fracture is substantially reduced.
According to the invention, the improved overhead electric transmission or distribution system comprises at least one overhead stranded electric conductor of the kind described freely supported in long lengths from towers spaced along the system, wherein at at least one tower of the system the said overhead stranded conductor or one of the said overhead stranded conductors is supported from each of two opposite sides of the tower by suspension means incorporating a weak link designed to fracture at a tensile load substantially less than that which the or each optical fibre and/or optical bundle of the stranded conductor can withstand before fracturing and wherein an excess length of the said stranded conductor extends between the positions at which said suspension means are secured to the stranded conductor, the arrangement being such that, in the event that the tensile load on the stranded conductor increases to a value greater than that which the weak links can withstand, one or each of the weak links will fracture and the excess length of stranded conductor will reduce substantially the tensile load on the stranded conductor and thereby substantially reduce risk of optical fibre fracture.
Preferably, the suspension means by which the overhead stranded conductor is supported from two opposite sides of the tower each comprises a stranded wire rope having a weak link connected between, or to one of, its ends.
Each weak link may be of any known form.
The excess length of stranded conductor at the tower is preferably arranged sinuously down one side face of the tower and, where the stranded conductor is an earth conductor, preferably is detachably secured to the tower at spaced positions along said excess length.
Neighbouring parts of the sinuously extending excess length of stranded conductor may be connected together by, or the sinuously extending excess length of stranded conductor may be detachably secured to the tower at spaced positions along its length by, releasable clips which will disengage in the event that the tensile load on the stranded conductor increases to a value greater than that which the weak links can withstand.
The excess length of stranded conductor arranged sinuously down one side face of the tower may include a joint between two adjoining lengths of stranded conductor of the kind described.
Where the overhead stranded electric conductor of the kind described is an earth conductor, the suspension means incorporating a weak link on each side of the tower may be secured to the top of the tower. Where the overhead stranded electric conductor of the kind described is a live conductor, the suspension means incorporating a weak link on each side of the tower may be suspended from an electric insulator or electric insulator string mounted on or suspended from a cross-arm of the tower.
The invention is further illustrated by a description, by way of example, of two preferred forms of overhead electric transmission system with reference to the accompanying diagrammatic drawing, in which: Figure 1 is a fragmental representation of a tower of the first preferred form of overhead electric transmission system, and,
Figure 2 is a fragmental representation of a tower of the second preferred form of overhead electric transmission system.
In the overhead electric transmission system shown in Fig. 1, an overhead stranded electric conductor 1 of the kind described is an earth conductor and, on each of two opposite sides of the upper part of a tower 2, the stranded conductor is supported from the top of the tower by a stranded wire rope 3 which has a weak link 4 interconnected between its ends, one end of the wire rope being secured to the top of the tower and the other end of the wire rope being secured to the stranded conductor 1 by a wedge type fitting 5. An excess length 6 of the stranded conductor 1 extends between the wedge type fittings 5 and is arranged sinuously down one side face of the tower 2, the excess length being detachably secured to the tower at spaced positions along its length by releasable clips 7.
Each weak link 4 is designed to fracture at a tensile load substantially less than that which the or each optical fibre and/or optical bundle of the stranded conductor 1 can withstand before fracturing.
In the event that the tensile load on the stranded conductor 1 increases to a value greater than that which the weak links 4 can withstand, one or each of the weal < links will fracture, the releasable clips 7 will disengage from the tower 2 and the excess length 6 of stranded conductor will reduce substantially the tensile load of the stranded conductor and will thereby substantially reduce risk of optical fibre fracture.
The second preferred form of overhead electric transmission system shown in Fig. 2 includes an earth conductor 1 9 suspended from the top of a tower 1 2 and at least one overhead stranded electric phase conductor 11 of the kind described which is freely supported from a cross arm 20 of the tower by an electric insulator 1 8 suspended from the cross arm.The stranded conductor 11 is supported from the lowermost end of the insulator 1 8 on each of two opposite sides of the tower 1 2 by a stranded wire rope 1 3 having a weak link 14 interconnected between its ends, one end of the wire rope being secured to the lowermost end of the insulator 1 8 and the other end of the wire rope being secured to the stranded conductor 1 by a wedge type fitting 1 5. An excess length 1 6 of the stranded conductor 11 extends between the wedge type fittings 1 5 and is arranged sinuously down and spaced transversely of the conductor from one side face of the tower, neighbouring parts of the sinuously extending excess length of stranded conductor being connected together by releasable clips 17. Each weak link 14 is designed to fracture at a tensile load substantially less than that which the or each optical fibre and/or optical bundle of the stranded conductor 11 can withstand before fracturing.
In the event that the tensile load on the stranded conductor 11 increases to a value greater than that which the weak links 1 4 can withstand, one or each of the weak links will fracture, the releasable clips 1 7 will disengage and the excess length of stranded conductor will reduce substantially the tensile load on the stranded conductor and will thereby substantially reduce risk of optical fibre fracture.
Claims (11)
1. An overhead electric transmission or distribution system comprising at least one overhead stranded electric conductor of the kind described freely supported in long lengths from towers spaced along the system, wherein at at least one tower of the system the said overhead stranded conductor or one of the said overhead stranded conductors is supported from each of two opposite sides of the tower by suspension means incorporating a weak link designed to fracture at a tensile load substantially less than that which the or each optical fibre and/or optical bundle of the stranded conductor can withstand before fracturing and wherein an excess length of the said stranded conductor extends between the positions at which said suspension means are secured to the stranded conductor, the arrangement being such that, in the event that the tensile load on the stranded conductor increases to a value greater than that which the weak links can withstand, one or each of the weak links will fracture and the excess length of stranded conductor will reduce substantially the tensile load on the stranded conductor and thereby substantially reduce risk of optical fibre fracture.
2. An overhead electric transmission or distribution system as claimed in Claim 1, wherein the suspension means by which the overhead stranded conductor is supported from two opposite sides of the tower each comprises a stranded wire rope having a weak
link connected between, or to one of, its ends.
3. An overhead electric transmission or distribution system as claimed in Claim 1 or 2, wherein the excess length of stranded conductor at the tower is arranged sinuously down one side face of the tower.
4. An overhead electric transmission or distribution system as claimed in Claim 3 in which the stranded conductor is an earth conductor, wherein the excess length of stranded conductor is detachably secured to the tower at spaced positions along said excess length.
5. An overhead electric transmission or distribution system as claimed in Claim 4, wherein the sinuously extending excess length of stranded conductor is detachably secured to the tower at spaced positions along its length by releasable clips which will disengage in the event that the tensile load on the stranded conductor increases to a value greater than that which the weak links can withstand.
6. An overhead electric transmission or distribution system as claimed in Claim 1 or 2 in which the stranded conductor is a live conductor, wherein the suspension means incorporating a weak link on each side of the tower is suspended from an electric insulator or electric insulator string mounted on or suspended from a cross-arm of the tower.
7. An overhead electric transmission or distribution system as claimed in Claim 6, wherein the excess length of stranded conductor at the tower is arranged sinuously down and spaced transversely of the conductor from one side face of the tower.
8. An overhead electric transmission or distribution system as claimed in Claim 7, wherein neighbouring parts of the sinuously extending excess length of stranded conductor are connected together by releasable clips which will disengage in the event that the tensile load on the stranded conductor increases to a value greater than that which the weak links can withstand.
9. An overhead electric transmission or distribution system as claimed in any one of
Claims 3 to 8, wherein the excess length of stranded conductor arranged sinuously down one side face of the tower includes a joint between two adjoining lengths of stranded conductor of the kind described.
1 0. An overhead electric transmission or distribution system as claimed in any one of
Claims 1 to 3 in which the stranded conductor is an earth conductor, wherein the suspension means incorporating a weak link on each side of the tower is secured to the top of the tower.
11. An overhead electric transmission system substantially as hereinbefore described with reference to and as shown in Fig. 1 of the accompanying drawing.
1 2. An overhead electric transmission system substantially as hereinbefore described with reference to and as shown in Fig. 2 of the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08217322A GB2104304B (en) | 1981-06-16 | 1982-06-15 | An improved overhead electric transmission or distribution system |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8118526 | 1981-06-16 | ||
| GB08217322A GB2104304B (en) | 1981-06-16 | 1982-06-15 | An improved overhead electric transmission or distribution system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2104304A true GB2104304A (en) | 1983-03-02 |
| GB2104304B GB2104304B (en) | 1985-01-16 |
Family
ID=26279818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08217322A Expired GB2104304B (en) | 1981-06-16 | 1982-06-15 | An improved overhead electric transmission or distribution system |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2104304B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4720267A (en) * | 1985-05-29 | 1988-01-19 | Jong Siegfried A De | Connector with internal electrical connections to be made optionally |
| DE4400619A1 (en) * | 1993-01-13 | 1994-07-14 | Bergner Richard Gmbh Co | Pylon supported overhead cable suspension for communications and LV conductors |
| EP0780713A1 (en) * | 1995-12-22 | 1997-06-25 | PIRELLI GENERAL plc | Suspended line for an optical fibre unit |
| DE19835645C1 (en) * | 1998-08-06 | 2000-03-30 | Siemens Ag | Cable laying method esp. for optical cables along roads and motorways |
| US7106931B2 (en) | 2001-11-19 | 2006-09-12 | Pirelli General Plc | Optical fiber drop cables |
| US7783147B2 (en) | 2001-11-19 | 2010-08-24 | Prysmian Cables & Systems Limited | Optical fibre drop cables |
| GB2545730A (en) * | 2015-12-23 | 2017-06-28 | Afl Global | A mechanical fuse for use with overhead telecommunications cable |
-
1982
- 1982-06-15 GB GB08217322A patent/GB2104304B/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4720267A (en) * | 1985-05-29 | 1988-01-19 | Jong Siegfried A De | Connector with internal electrical connections to be made optionally |
| DE4400619A1 (en) * | 1993-01-13 | 1994-07-14 | Bergner Richard Gmbh Co | Pylon supported overhead cable suspension for communications and LV conductors |
| EP0780713A1 (en) * | 1995-12-22 | 1997-06-25 | PIRELLI GENERAL plc | Suspended line for an optical fibre unit |
| US5727106A (en) * | 1995-12-22 | 1998-03-10 | Pirelli General Plc | Suspended line for an optical fibre unit |
| DE19835645C1 (en) * | 1998-08-06 | 2000-03-30 | Siemens Ag | Cable laying method esp. for optical cables along roads and motorways |
| US7106931B2 (en) | 2001-11-19 | 2006-09-12 | Pirelli General Plc | Optical fiber drop cables |
| US7783147B2 (en) | 2001-11-19 | 2010-08-24 | Prysmian Cables & Systems Limited | Optical fibre drop cables |
| GB2545730A (en) * | 2015-12-23 | 2017-06-28 | Afl Global | A mechanical fuse for use with overhead telecommunications cable |
| GB2545730B (en) * | 2015-12-23 | 2018-11-14 | Afl Global | A mechanical fuse for use with overhead telecommunications cable |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2104304B (en) | 1985-01-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |