CA1153434A - Aluminum conductor with a stress-reducing structure - Google Patents
Aluminum conductor with a stress-reducing structureInfo
- Publication number
- CA1153434A CA1153434A CA000340000A CA340000A CA1153434A CA 1153434 A CA1153434 A CA 1153434A CA 000340000 A CA000340000 A CA 000340000A CA 340000 A CA340000 A CA 340000A CA 1153434 A CA1153434 A CA 1153434A
- Authority
- CA
- Canada
- Prior art keywords
- strands
- aluminum
- aluminum strands
- section
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT OF THE DISCLOSURE
In an ACSR conductor the aluminum strands are helically wound on the steel core in one or more layers, the strands in each layer being circumferentially spaced from one another to provide clearances which accommodate changes of length of the strands due to thermal expansion, thereby avoiding the subjection of the strands to compressive stresses at high temperatures which would augment the tensile stress in the steel core and thus increase the conductor sag. The invention also envisages con-trolling the amount of slack in the aluminum conductor strands for controlling the stress/temperature characteristics thereof.
The invention also envisages the use of strands having a trun-cated segmental cross-section in order to reduce creep.
.
In an ACSR conductor the aluminum strands are helically wound on the steel core in one or more layers, the strands in each layer being circumferentially spaced from one another to provide clearances which accommodate changes of length of the strands due to thermal expansion, thereby avoiding the subjection of the strands to compressive stresses at high temperatures which would augment the tensile stress in the steel core and thus increase the conductor sag. The invention also envisages con-trolling the amount of slack in the aluminum conductor strands for controlling the stress/temperature characteristics thereof.
The invention also envisages the use of strands having a trun-cated segmental cross-section in order to reduce creep.
.
Description
~3~3~
This invention relates to composite conductors of the type used in power transmission lines and is primarily concerned with ACSR (Aluminum Co~ductor Steel Reinorced) conductors. The invention is, however, also applicable to all-aluminum stranded conductors, which hit~erto have not been satis~actory in long spans owing to creep problems inherent in their design.
The current design of ACSR conductors is such as to pro-duce excessive sags at higher operating temperatures. Also these conductors are sùbject to additional sag due to long term creep.
From a study of these problems it has been found by applicants that the effects of temperature and creep can be greatly reduced by certain changes to the conductor structure.
When an ACSR conductor is strung in a span o-E a transmission line, the aluminum and steel strands share the resultant mechani-cal tension in a manner determined by the aluminum to s-teel ratio, temperature and creep. When heated by the line current, the conductor is elongated as the aluminum and steel expand at their respective rates, and this results in an increase in sag and a reduction in total conductor tension. However, tests on conventional ACSR conductors at higher operating temperatures have shown that the measured sags are considerably greater than one would expect from calculations by accepted methods. In the accepted methods of sag calculation it is assumed that as the conductor temperature increases the aluminum becomes completely unloaded at a certain temperature, due to its having a higher coefficient of thermal expansion than the steel, and plays no further role byond this temperature except for its effect on the total conductor mass. Accordingly, it is assumed that at elevate~
temperatures the conductor sag is determined entirely by the thermal e~pansion characteristics of the steel. EIowever, tests have shown that the stress in the aluminum does not remain zero above the critical temperature but reverses, that is to say, the aluminum goes into compression after the zero load condition ~ 1 --has been reache~. The compressive load in the aluminum results in increasec1 tensile stress in the s-teel core and so produces additional elongation and sag. At some higher temperature the aluminum strands ~inally de~orm by birdcaging and the internal stresses are relieved, the compressive stress in the aluminum at which this occurs depending mainly on the conductor structure.
In some conductors a compressive stress in the aluminum as high as 2500 psi has been observed.
Creep in conventional ACSR conductors is a term used to describe the long term elongation of a conductor under tension.
Naturally, any elongation will result in additional sags which must be considered in the line design. Creep is normally attributed to elongation of the aluminum under tension, resulting in transfer of load to the steel which elongates elastically under increased loads. Studies of the creep phenomena have shown that at normal operating tensions and temperatures the tensile creep in the aluminum is very small and does not account for the ob-served creep in composite ACSR conductors. Applicants' ex-periments and analysis show that the creep of ACSR conductors is actually due to radial deformation of aluminum strands, which deformation results in a transfer of load from the aluminum to the steel. This deformation is the result of axial tension being transformed into radial compressive forces between helically wound strands and it takes place at the strand crossings at which the load bearing areas of contact between the strands are insufficient.
The present invention relates to composite conductor structures based on the foregoing considerations, the structures being such as to minimize the effects of temperature and creep on conductor sag.
According to one aspect of the invention, in an ACSR con-ductor having a steel core with one or more layers of helically wound aluminum strands thereon, the aluminum strands are spaced L3~L
circumferentially from one ano-ther, thereby providing clearances -to accommodate thermal expansion of the strands and so prevent additional tensile loading of -the steel core and thus reduce sags at high temperatures.
The aluminum strands may be of round cross-section, the circumferential clearances therebetween being at least 0.005 inch, and the steel strands may be of round or ~runcated segmental cross-section. Alternatively, the aluminum strands may be of truncated segmental cross-section, the circumferential clearances threbetween being at least 0.003 inch. To minimize creep due to radial compressive forces between the conductor strands a-t the strand crossing points the strands are preferably of trun-cated segmental cross-section to provide large areas of contact at the crossing points. To set the temperature at which the aluminum becomes unstressed a controlled amount of slack can be provided in the aluminum strands during manufacture, and accord-ing to the present invention this is accomplished by interposing a deformable spacing means between the steel core and the aluminum strands. The result is that at low temperatures when the tension is high the aluminum bears some of the load but at higher temperatures the aluminum birdcages and the sag is re-duced. Creep is also reduced because the slack lowers the aluminum strass.
According to another aspect of the invention, as applied to an all-aluminum stranded conductor, the strands are arranged as a plurality of concentric layers and are of truncated segmental cross-section to provide large areas of contact at the crossing points. In this way the radial compressive forces whiah give rise to creep, and which have made all-aluminum conductors un-satisfactory in the past, can be greatly reduced.
Several embodiments of the invention will now be described,by way of example, with reference to the accompanying drawings in which:
53~
Figure 1 illustrates a portion of a first ACSR conductor in accordance with the invention;
Figure 2 illus-trates a portion of a second ACSR conductor in accordance with the invention;
Figure 3 illustrates a portion of a third ACSR conductor in accordance with the invention;
Figure 4 illustrates a detail of the structure shown in Figure 3;
` Figure 5 illustrates a portion of a fourth ACSR conductor in accordance with the invention;
Figure 6 illustrates a detail of the structure shown in Figure 5;
Figure 7 illustrates a portion of a fifth ACSR conductor in accordance with the invention;
Figure 8 illustrates a portion of an ACSR conductor similar to that of Figure 5 but having only one layer of aluminum strands; and Figure 9 illustrates a portion of an all-aluminum stranded conductor in accordance with the invention.
The composite conductor shown in Figure 1 comprises a steel core 10 of round cross-section, the core being compose~ o~
helically wound steel strands 11 which are individually of round cross-section. Aluminum strands 12, which are of conventional round cross-section, are helically wound in a single layer on the steel core, the aluminum strands crossing the steel strands at crossing points 13 which provide relatively small elliptical areas of contact. The invention is characterized by the act that the strands 12 are circumferentially spaced from one another to provide clearances 14. With this structure, at low tempera-tures the total tensile stress of the conductor is shared between the aluminum strands and the steel strands, the tensile stress inthe aluminum strands being reduced as the strands elongate with increasing temperature. However, up to a certain ~ .53~3~
temperature for which -the conductor is ~esigned the clearances 14 can accommodate elongations o~ the aluminum strands so that they are not placed in compression as in the case of a convention-al ACSR conductor and so do not transfer an additional tensile load to the steel core. It has been calculated that, ~or a con-ductor of the construction illustrated in Figure 1, the clearances between the aluminum strands should be at least 0.005 inch to accommodate thermal expansions up to a maximum temperature of 200C.
It will be appreciated that the structure shown in Flgure 1 may be modified by adding one or more further layers of helical-ly wound aluminum strands, the strands of each layer being spaced circumferentially from one another as in the innermost layer, the layers of strands being helically wound in opposite direc-tions alternately.
The struc~ure illustrated in Figure 2 is basically similar to that of Figure 1, having a stranded steel core 10 with indi-vidual strands 11 of round cross-section. The aluminum strands 15, however, are of truncated segmental cross-section, that is to say, the cross-section is defined by a short length of an annulus. With this construction the strand crossing points 16 provide larger load bearing areas than do the crossing points 13 of the èarlier construction, so that the radial compressive stresses are greatly reduced and the creep prohlem is reduced.
In this case, the strands 15 are circumferentially spaced from one another to provide clearances 14, and to accommodate dif-ferential elongation of the aluminum strands up to a temperature of 200C these clearances should be at least 0.003 inch.
As in the construction earlier described, this structure may be modified by the addition of one or more layers o~ alumin~m strands, the layers of strands being helically wound alternately in opposite directions, and the strands of each layer being circumferentially spaced from one another.
.
~S3434 Referriny now ~o Figures 3 and 4, -the third ACSR conductor has a stranded steel core of round cross-section composed of steel strands 17 which are oE truncated segmental cross-section.
The aluminum strands 15 are also oE truncated segmental cross-section, and are helically wound in two concentric layers 18, 19, the strands of each layer being circumferentially spaced to provide clearances 14. It will be appreciated that the structure may be modified by the addition of further concentric layers of aluminum strands, or by the provision of just a single layer 18.
This embodiment of the invention is characterized by the fact that the strands 15 of the innermost layer 18 are formed with int:egral deformable pointed projections 20 e~tending radially inwardly from their inner surfaces and bearing on the outer strands 17 of the steel core. These projections 20 act as de-formable spacing means interposed be~ween-the steel core and the aluminum strands, to provide a certain amount of spacing prior to installation of the conduc~or, the projections yielding under compressive forces when the conductor is suspPnded and so furnishing a controlled amount of slack in the aluminum strands.
The reason for providing the deformable spacing means is to con-trol the initial slack which affects the load distribution of the conductor. With a controlled amount of slack the aluminum will bear some of the load at low temperatures but will birdcage at higher temperatures. The thermal expansion after birdcaging temperature occurs only at the rate of the steel and so sags are reduced. Reduced creep is an added benefit of the lower aluminum tension.
Figure 5 illustra ~s a modification of this structure, in which the steel core is composed of strands 11 of round cross-section, as in the earlier embodiments, and in which the helicallywound aluminum strands 15 are of truncated segmental cross-section, the strands of each layer being circumferentially spaced from one another to provide the clearances 14. In this 31 ~53~
cons-truction, the s-trands of -the innermost layer 18 are formed on their inner faces wi-th integral longitudinally extending ridges 21, which act as deformable spacing means exactly as the projections 20 (Fig. 4) of the previous embodiment. Figure 6 shows a detail o~ this cons-truction, in which a strand 15 of the innermost layer 18 is formed with the deformable ridges 21 which bear against the outer strands 11 of the steel core at crossing points 22.
Figure 7 illustrates yet another construction which is very similar to that of Figure 5, having a steel core of round cross-section with strands 11, and at least one layer of helically wound aluminum strands 15 which are spaced circumferentially from one another to provide the clearances 14. In this con-struction, however, instead of projections or ridges being formed on the inner faces of the aluminum strands, a layer of plastical-ly deformable material 22 is interposed between the steel core 11 and the aluminum conductor strands 15. The material 22 can be practically any material which will serve as a spacer initial-ly and yield to radial loads so as to provide the required amount of slack in the aluminum strands, polyvinyl chloride being a suitable material which is readily available.
The structure shown in Figure 8 is essentially the same as that of Figure 5, the only difference being that the aluminum strands are arranged in a single layer 18.
Figure 9 shows an all-aluminum conductor of round cross-section consisting of a plurality of concentric layers of aluminum strands 23. The aluminum strands 23 are of truncated segmental cross-section. The central strand 24 is of circular cross-section. It will be seen that the strands of each layer engage the strands of the adjacent layers over large areas of contact, thereby minimizing the radial compressive loads and so minimizing creep problems. The strands are, of course, helically wound the helices of adjacent layers being of opposite hand.
This invention relates to composite conductors of the type used in power transmission lines and is primarily concerned with ACSR (Aluminum Co~ductor Steel Reinorced) conductors. The invention is, however, also applicable to all-aluminum stranded conductors, which hit~erto have not been satis~actory in long spans owing to creep problems inherent in their design.
The current design of ACSR conductors is such as to pro-duce excessive sags at higher operating temperatures. Also these conductors are sùbject to additional sag due to long term creep.
From a study of these problems it has been found by applicants that the effects of temperature and creep can be greatly reduced by certain changes to the conductor structure.
When an ACSR conductor is strung in a span o-E a transmission line, the aluminum and steel strands share the resultant mechani-cal tension in a manner determined by the aluminum to s-teel ratio, temperature and creep. When heated by the line current, the conductor is elongated as the aluminum and steel expand at their respective rates, and this results in an increase in sag and a reduction in total conductor tension. However, tests on conventional ACSR conductors at higher operating temperatures have shown that the measured sags are considerably greater than one would expect from calculations by accepted methods. In the accepted methods of sag calculation it is assumed that as the conductor temperature increases the aluminum becomes completely unloaded at a certain temperature, due to its having a higher coefficient of thermal expansion than the steel, and plays no further role byond this temperature except for its effect on the total conductor mass. Accordingly, it is assumed that at elevate~
temperatures the conductor sag is determined entirely by the thermal e~pansion characteristics of the steel. EIowever, tests have shown that the stress in the aluminum does not remain zero above the critical temperature but reverses, that is to say, the aluminum goes into compression after the zero load condition ~ 1 --has been reache~. The compressive load in the aluminum results in increasec1 tensile stress in the s-teel core and so produces additional elongation and sag. At some higher temperature the aluminum strands ~inally de~orm by birdcaging and the internal stresses are relieved, the compressive stress in the aluminum at which this occurs depending mainly on the conductor structure.
In some conductors a compressive stress in the aluminum as high as 2500 psi has been observed.
Creep in conventional ACSR conductors is a term used to describe the long term elongation of a conductor under tension.
Naturally, any elongation will result in additional sags which must be considered in the line design. Creep is normally attributed to elongation of the aluminum under tension, resulting in transfer of load to the steel which elongates elastically under increased loads. Studies of the creep phenomena have shown that at normal operating tensions and temperatures the tensile creep in the aluminum is very small and does not account for the ob-served creep in composite ACSR conductors. Applicants' ex-periments and analysis show that the creep of ACSR conductors is actually due to radial deformation of aluminum strands, which deformation results in a transfer of load from the aluminum to the steel. This deformation is the result of axial tension being transformed into radial compressive forces between helically wound strands and it takes place at the strand crossings at which the load bearing areas of contact between the strands are insufficient.
The present invention relates to composite conductor structures based on the foregoing considerations, the structures being such as to minimize the effects of temperature and creep on conductor sag.
According to one aspect of the invention, in an ACSR con-ductor having a steel core with one or more layers of helically wound aluminum strands thereon, the aluminum strands are spaced L3~L
circumferentially from one ano-ther, thereby providing clearances -to accommodate thermal expansion of the strands and so prevent additional tensile loading of -the steel core and thus reduce sags at high temperatures.
The aluminum strands may be of round cross-section, the circumferential clearances therebetween being at least 0.005 inch, and the steel strands may be of round or ~runcated segmental cross-section. Alternatively, the aluminum strands may be of truncated segmental cross-section, the circumferential clearances threbetween being at least 0.003 inch. To minimize creep due to radial compressive forces between the conductor strands a-t the strand crossing points the strands are preferably of trun-cated segmental cross-section to provide large areas of contact at the crossing points. To set the temperature at which the aluminum becomes unstressed a controlled amount of slack can be provided in the aluminum strands during manufacture, and accord-ing to the present invention this is accomplished by interposing a deformable spacing means between the steel core and the aluminum strands. The result is that at low temperatures when the tension is high the aluminum bears some of the load but at higher temperatures the aluminum birdcages and the sag is re-duced. Creep is also reduced because the slack lowers the aluminum strass.
According to another aspect of the invention, as applied to an all-aluminum stranded conductor, the strands are arranged as a plurality of concentric layers and are of truncated segmental cross-section to provide large areas of contact at the crossing points. In this way the radial compressive forces whiah give rise to creep, and which have made all-aluminum conductors un-satisfactory in the past, can be greatly reduced.
Several embodiments of the invention will now be described,by way of example, with reference to the accompanying drawings in which:
53~
Figure 1 illustrates a portion of a first ACSR conductor in accordance with the invention;
Figure 2 illus-trates a portion of a second ACSR conductor in accordance with the invention;
Figure 3 illustrates a portion of a third ACSR conductor in accordance with the invention;
Figure 4 illustrates a detail of the structure shown in Figure 3;
` Figure 5 illustrates a portion of a fourth ACSR conductor in accordance with the invention;
Figure 6 illustrates a detail of the structure shown in Figure 5;
Figure 7 illustrates a portion of a fifth ACSR conductor in accordance with the invention;
Figure 8 illustrates a portion of an ACSR conductor similar to that of Figure 5 but having only one layer of aluminum strands; and Figure 9 illustrates a portion of an all-aluminum stranded conductor in accordance with the invention.
The composite conductor shown in Figure 1 comprises a steel core 10 of round cross-section, the core being compose~ o~
helically wound steel strands 11 which are individually of round cross-section. Aluminum strands 12, which are of conventional round cross-section, are helically wound in a single layer on the steel core, the aluminum strands crossing the steel strands at crossing points 13 which provide relatively small elliptical areas of contact. The invention is characterized by the act that the strands 12 are circumferentially spaced from one another to provide clearances 14. With this structure, at low tempera-tures the total tensile stress of the conductor is shared between the aluminum strands and the steel strands, the tensile stress inthe aluminum strands being reduced as the strands elongate with increasing temperature. However, up to a certain ~ .53~3~
temperature for which -the conductor is ~esigned the clearances 14 can accommodate elongations o~ the aluminum strands so that they are not placed in compression as in the case of a convention-al ACSR conductor and so do not transfer an additional tensile load to the steel core. It has been calculated that, ~or a con-ductor of the construction illustrated in Figure 1, the clearances between the aluminum strands should be at least 0.005 inch to accommodate thermal expansions up to a maximum temperature of 200C.
It will be appreciated that the structure shown in Flgure 1 may be modified by adding one or more further layers of helical-ly wound aluminum strands, the strands of each layer being spaced circumferentially from one another as in the innermost layer, the layers of strands being helically wound in opposite direc-tions alternately.
The struc~ure illustrated in Figure 2 is basically similar to that of Figure 1, having a stranded steel core 10 with indi-vidual strands 11 of round cross-section. The aluminum strands 15, however, are of truncated segmental cross-section, that is to say, the cross-section is defined by a short length of an annulus. With this construction the strand crossing points 16 provide larger load bearing areas than do the crossing points 13 of the èarlier construction, so that the radial compressive stresses are greatly reduced and the creep prohlem is reduced.
In this case, the strands 15 are circumferentially spaced from one another to provide clearances 14, and to accommodate dif-ferential elongation of the aluminum strands up to a temperature of 200C these clearances should be at least 0.003 inch.
As in the construction earlier described, this structure may be modified by the addition of one or more layers o~ alumin~m strands, the layers of strands being helically wound alternately in opposite directions, and the strands of each layer being circumferentially spaced from one another.
.
~S3434 Referriny now ~o Figures 3 and 4, -the third ACSR conductor has a stranded steel core of round cross-section composed of steel strands 17 which are oE truncated segmental cross-section.
The aluminum strands 15 are also oE truncated segmental cross-section, and are helically wound in two concentric layers 18, 19, the strands of each layer being circumferentially spaced to provide clearances 14. It will be appreciated that the structure may be modified by the addition of further concentric layers of aluminum strands, or by the provision of just a single layer 18.
This embodiment of the invention is characterized by the fact that the strands 15 of the innermost layer 18 are formed with int:egral deformable pointed projections 20 e~tending radially inwardly from their inner surfaces and bearing on the outer strands 17 of the steel core. These projections 20 act as de-formable spacing means interposed be~ween-the steel core and the aluminum strands, to provide a certain amount of spacing prior to installation of the conduc~or, the projections yielding under compressive forces when the conductor is suspPnded and so furnishing a controlled amount of slack in the aluminum strands.
The reason for providing the deformable spacing means is to con-trol the initial slack which affects the load distribution of the conductor. With a controlled amount of slack the aluminum will bear some of the load at low temperatures but will birdcage at higher temperatures. The thermal expansion after birdcaging temperature occurs only at the rate of the steel and so sags are reduced. Reduced creep is an added benefit of the lower aluminum tension.
Figure 5 illustra ~s a modification of this structure, in which the steel core is composed of strands 11 of round cross-section, as in the earlier embodiments, and in which the helicallywound aluminum strands 15 are of truncated segmental cross-section, the strands of each layer being circumferentially spaced from one another to provide the clearances 14. In this 31 ~53~
cons-truction, the s-trands of -the innermost layer 18 are formed on their inner faces wi-th integral longitudinally extending ridges 21, which act as deformable spacing means exactly as the projections 20 (Fig. 4) of the previous embodiment. Figure 6 shows a detail o~ this cons-truction, in which a strand 15 of the innermost layer 18 is formed with the deformable ridges 21 which bear against the outer strands 11 of the steel core at crossing points 22.
Figure 7 illustrates yet another construction which is very similar to that of Figure 5, having a steel core of round cross-section with strands 11, and at least one layer of helically wound aluminum strands 15 which are spaced circumferentially from one another to provide the clearances 14. In this con-struction, however, instead of projections or ridges being formed on the inner faces of the aluminum strands, a layer of plastical-ly deformable material 22 is interposed between the steel core 11 and the aluminum conductor strands 15. The material 22 can be practically any material which will serve as a spacer initial-ly and yield to radial loads so as to provide the required amount of slack in the aluminum strands, polyvinyl chloride being a suitable material which is readily available.
The structure shown in Figure 8 is essentially the same as that of Figure 5, the only difference being that the aluminum strands are arranged in a single layer 18.
Figure 9 shows an all-aluminum conductor of round cross-section consisting of a plurality of concentric layers of aluminum strands 23. The aluminum strands 23 are of truncated segmental cross-section. The central strand 24 is of circular cross-section. It will be seen that the strands of each layer engage the strands of the adjacent layers over large areas of contact, thereby minimizing the radial compressive loads and so minimizing creep problems. The strands are, of course, helically wound the helices of adjacent layers being of opposite hand.
Claims (9)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An ACSR conductor having a stranded steel core with one or more layers of helically wound aluminum strands thereon, wherein the aluminum strands in each layer are spaced circum-ferentially from one another.
2. An ACSR conductor according to claim 1, wherein both the steel and aluminum strands are of round cross-section, the circumferential clearances being at least 0.005 inch between the aluminum strands.
3. An ACSR conductor according to claim 1, wherein the steel strands are of truncated segmental cross-section and the aluminum strands are of round cross-section, the circumferential clearances being at least 0.005 inch between the aluminum strands.
4. An ACSR conductor according to claim 1, including deformable spacing means interposed between the steel core and the aluminum strands.
5. An ACSR conductor according to claim 4, said deformable means comprising a layer of plastically deformable material enveloping the core.
6. An ACSR conductor according to claim 1, wherein the steel strands are of round cross-section and the aluminum strands are of truncated segmental cross-section the circumferential clearances being at least 0.003 inch between the aluminum strands.
7. An ACSR conductor according to claim 6, having deformable spacing means comprising integral longitudinally extending ridges extending radially inward from the innermost layer of aluminum strands and bearing on the core.
8. An ACSR conductor according to claim 1, wherein both the steel and aluminum strands are of truncated segmental cross-section, the circumferential clearances being at least 0.003 inch between the aluminum strands.
9. An ACSR conductor according to claim 8, having deformable spacing means comprising integral pointed projections extending radially inward from the innermost layer of aluminum strands and bearing on the core.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US96876378A | 1978-12-12 | 1978-12-12 | |
| US968,763 | 1992-10-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1153434A true CA1153434A (en) | 1983-09-06 |
Family
ID=25514736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000340000A Expired CA1153434A (en) | 1978-12-12 | 1979-11-16 | Aluminum conductor with a stress-reducing structure |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1153434A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102139544A (en) * | 2003-10-22 | 2011-08-03 | Ctc电缆公司 | Aluminum conductor composite core reinforced cable and method of manufacturing the same |
-
1979
- 1979-11-16 CA CA000340000A patent/CA1153434A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102139544A (en) * | 2003-10-22 | 2011-08-03 | Ctc电缆公司 | Aluminum conductor composite core reinforced cable and method of manufacturing the same |
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