The clamp is used to monitor the central load-bearing wire for overhead transmission lines and overhead transmission line systems that include this clamp.

Abstract

The invention relates to a clamp for monitoring the central load-bearing wire of an overhead transmission line and an overhead transmission line system including such a clamp. Specifically, this invention relates to a clamp for monitoring the central load-bearing wire of an overhead transmission line and an overhead transmission line system including such a clamp, capable of easily and accurately detecting whether the central load-bearing wire is damaged not only immediately before installing the overhead transmission line on the steel pole but also after installing the overhead transmission line on the steel pole, and improving the workability of the overhead transmission line installation and the stability of the workers.

Description

Clamp having a monitoring function for a central tension wire for overhead transmission lines and an overhead transmission line system including the same

[0001] The present invention relates to a clamp having a monitoring function for a central tension wire for an overhead transmission line and to an overhead transmission line system including the same. Specifically, the present invention relates to a clamp having a monitoring function for a central tension wire for an overhead transmission line and to an overhead transmission line system including the same, which can easily and accurately detect whether a central tension wire is damaged not only immediately before installing an overhead transmission line on a tower but also after installing the overhead transmission line on the tower, thereby improving the workability of overhead transmission line installation work and the safety of workers.

[0002] There are two methods for supplying electricity from power plants to cities and factories through substations: overhead transmission, which uses overhead transmission lines connected to towers, and underground transmission, which uses underground transmission lines buried underground. Overhead transmission accounts for approximately 90% of domestic power transmission methods.

[0003] Conventionally, overhead transmission lines are generally made of aluminum conductor steel reinforced (ACSR) overhead transmission lines, which are made by stranding multiple aluminum alloy conductors around a central tension wire to achieve high-tensile properties. In addition, the overhead transmission lines are installed by fastening clamps to both ends and fixing the clamps to a steel tower, and on the steel tower, the clamps of each of the fixed multiple overhead transmission lines are connected with separate jumper cables, thereby allowing the multiple overhead transmission lines to be connected as a whole.

[0004] However, the above-mentioned aluminum core stranded conductor (ACSR) overhead transmission line has a large sag due to the large load of the core itself used as the central tension wire, and there is a limit to increasing the weight of the aluminum conductor to increase the power transmission capacity of the overhead transmission line. In order to reduce the sag of the overhead transmission line or increase the power transmission capacity with the same sag, there have been attempts to reduce the weight of the overhead transmission line by using fiber-reinforced composite materials in the central tension wire.

[0005] Figure 1 schematically illustrates the cross-sectional structure of a conventional overhead transmission line having a central tension line including a fiber-reinforced composite.

[0006] As illustrated in FIG. 1, a conventional overhead transmission line may include a central tension line (10) and a conductor line (20) arranged around the central tension line, and the central tension line (10) may include a core layer (11) made of a carbon fiber reinforced composite material and a cover layer (12) made of a glass fiber reinforced composite material to suppress corrosion of the conductor line (20) due to galvanic corrosion, i.e., dissimilar metal contact corrosion between the core layer (11) and the conductor line (20).

[0007] However, these conventional overhead transmission lines have limitations in reducing the weight of the overhead transmission lines due to the high specific gravity of the glass fiber reinforced composite constituting the cover layer (12) of the central tension line (10), for example, a specific gravity of about 2.0 g / cm3, and thus, not only may the conductivity characteristics be deteriorated, but also, due to the high hardness of the glass fiber reinforced composite, the conductor wire (20) arranged around the central tension line and in contact with and rubbing against the cover layer (12) may be damaged, resulting in problems of increased resistance and reduced power transmission due to a decrease in the cross-sectional area of ​​the conductor wire (20). In addition, there is also a problem of increased manufacturing costs of the overhead transmission line due to the application of a relatively expensive glass fiber reinforced composite.

[0008] In addition, since the conductor wire (20) of the conventional overhead transmission line is arranged around the center tension wire (10), there is a problem in that it is impossible to check whether the center tension wire (10) arranged inside the overhead transmission line is damaged immediately before installation of the overhead transmission line.

[0009] Meanwhile, a technology has been applied to insert an optical fiber into the center tension line (10), transmit light of a specific wavelength to one end of the center tension line (10) through an optical transmission device, and install a light detection device at the other end of the center tension line (10) to check whether the transmitted light is detected, thereby checking whether the optical fiber is broken, and thereby checking whether the center tension line (10) is broken.

[0010] However, when an optical fiber is inserted inside the central tension line (10), there is a problem in that it is difficult to accurately detect whether the central tension line is broken, such as the optical fiber is not broken even if the central tension line (10) is broken, or conversely, the central tension line (10) is not broken but only the optical fiber is broken.

[0011] In addition, since it is a method of checking for damage by installing an optical transmission device and an optical detection device at each end of the central tension line (10), it is possible to check for damage only before clamping work on the overhead transmission line, and it is not possible to detect damage after installation of the overhead transmission line. In addition, there is a problem that the overhead transmission line installation work is delayed and complicated, and workability is reduced, as the worker must install an optical transmission device and an optical detection device to check for damage to the central tension line before clamping work on the steel tower.

[0012] Furthermore, when observing with the naked eye the optical signal transmitted from one end of the optical fiber inserted into the central tension line (10) to the other end, it is only possible to detect whether the optical fiber is completely broken, and it is impossible to detect where the optical fiber and the central tension line are broken.

[0013] Accordingly, there is an urgent need for a clamp having a center tension wire breakage detection function for overhead transmission lines and an overhead transmission line system including the clamp, which can easily and accurately detect breakage of the center tension wire not only immediately before installing the overhead transmission line on the tower but also after installing the overhead transmission line on the tower, thereby improving the workability of overhead transmission line installation work.

[0014] The present invention aims to provide a clamp having a breakage detection function for a center tension wire for an overhead transmission line, which can easily and accurately detect breakage of a center tension wire not only immediately before installing an overhead transmission line on a tower but also after installing an overhead transmission line on a tower, thereby improving the workability of overhead transmission line installation work, and an overhead transmission line system including the clamp.

[0015] In order to solve the above problem, the present invention,

[0016] A clamp for an overhead transmission line for installing an overhead transmission line including a central tension wire and an aluminum wire disposed around the central tension wire on a steel tower, the clamp comprising: a main body part having a hollow hole into which the overhead transmission line can be inserted and fixing the aluminum wire of the overhead transmission line inserted into the hollow hole; and a tension part having a connecting link for fixing the central tension wire of the overhead transmission line inserted into the hollow hole and connecting the overhead transmission line to the steel tower, wherein the main body part and the tension part are provided with a through hole through which a detection optical fiber provided in the central tension wire can pass and be drawn out to the outside.

[0017] Here, a clamp for an overhead transmission line is provided, characterized in that it further includes a jumper terminal that is fastened to the main body and to which a jumper cable is connected, and the optical fiber for detection is connected to an optical fiber for connection provided in the jumper cable.

[0018] In addition, the above-mentioned jumper terminal includes a first jumper terminal connected to the main body and a second jumper terminal connected to the jumper cable, and a clamp for an overhead transmission line is provided, characterized in that the first jumper terminal and the second jumper terminal are combined.

[0019] And, the first jumper terminal is provided with a through hole through which the optical fiber for detection can pass and be drawn out to the outside, and the second jumper terminal is provided with a through hole through which the optical fiber for connection can pass and be drawn out to the outside, and a clamp for an overhead transmission line is provided.

[0020] Furthermore, a clamp for an overhead transmission line is provided, characterized in that an optical fiber coupler is provided at each of the drawn ends of the optical fiber for detection and the optical fiber for connection to be coupled to each other.

[0021] Here, a clamp for an overhead transmission line is provided, characterized in that it further includes a kit case that covers the optical fiber coupler and is connected to the first jumper terminal.

[0022] In addition, a clamp for an overhead transmission line is provided, characterized in that the empty space inside the kit case is filled with a filler.

[0023] And, a clamp for an overhead transmission line is provided, characterized in that the filler is silicone or epoxy resin.

[0024] Meanwhile, a clamp for an overhead transmission line is provided, characterized in that a portion of the end of the central tension line is pulled out through the through hole together with a detection optical fiber provided on the central tension line.

[0025] In addition, the present invention provides a clamp for an overhead transmission line, characterized in that the jumper cable includes a steel tube and a connecting optical fiber mounted inside the steel tube, and the steel tube is drawn out through a through hole of the second jumper terminal and inserted into the inside of the kit case.

[0026] Meanwhile, an overhead transmission line system is provided, comprising a plurality of overhead transmission lines; and an overhead transmission line clamp according to any one of claims 1 to 8, which is fastened to both ends of each of the plurality of overhead transmission lines.

[0027] In addition, a clamp for an overhead transmission line is provided, characterized in that the plurality of overhead transmission lines include a central tension line in the form of a plurality of wires joined together.

[0028] Furthermore, a clamp for an overhead transmission line is provided, characterized in that a detection optical fiber is provided inside each of two or more of the plurality of small wires, some of the detection optical fibers detect whether the central tension line is broken, and the remaining some of the detection optical fibers detect other factors.

[0029] And, a method for constructing an overhead transmission line is provided, including the steps of: attaching clamps for the overhead transmission line to both ends of the overhead transmission line; transporting the overhead transmission line with the clamps attached to both ends to a construction location; connecting a connecting ring of a tension part in the clamp to the construction location; attaching a jumper terminal connected to a jumper cable to a main body part in the clamp; and connecting a detection optical fiber provided in a central tension line of the overhead transmission line and a connection optical fiber provided in the jumper cable to each other.

[0030] The clamp having a monitoring function of a central tension wire for an overhead transmission line according to the present invention and the overhead transmission line system including the same have an optical fiber that can detect whether the central tension wire is damaged or not in a plurality of overhead transmission lines that are connected as a whole via a plurality of steel towers through a novel structure of the clamp, thereby enabling easy and accurate detection of whether the central tension wire is damaged or not not only immediately before installation on a steel tower but also after installation of the overhead transmission line on the steel tower, and exhibiting an excellent effect of improving the workability of overhead transmission line installation work.

[0031] In addition, since the overhead transmission line is clamped from the factory and the optical fiber for detection is connected, it is transported to the installation location, so there is no need for workers to clamp on the tower, which has the effect of ensuring the workability of the overhead transmission line installation work and the safety of workers.

[0032] Figure 1 schematically illustrates the cross-sectional structure of a conventional overhead transmission line.

[0033] Figure 2 is an example of a cross-section of an overhead transmission line applied to an overhead transmission line system according to the present invention.

[0034] FIG. 3 is an example of a cross-section of a central tension line applied to the overhead transmission line illustrated in FIG. 2a.

[0035] Fig. 4 is a longitudinal cross-sectional view showing the detection part exposed from the core layer along the central tension line illustrated in Fig. 3.

[0036] Figure 5 is a schematic illustration of one end of the overhead transmission line shown in Figure 2 being fastened to a clamp.

[0037] Figure 6 schematically illustrates the configuration of the clamps in Figure 5 separated from each other.

[0038] Fig. 7 is one embodiment of a cross-section of the jumper cable illustrated in Fig. 5.

[0039] Figure 8 is a schematic diagram showing an example of detecting damage to a central tension line using an OTDR (Optical Time Domain Deflectometers) method.

[0040] Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosure is thorough and complete, and to sufficiently convey the spirit of the present invention to those skilled in the art. Like reference numerals designate like elements throughout the specification. Figure 2 illustrates an embodiment of a cross-section of an overhead transmission line applied to an overhead transmission line system according to the present invention.

[0041] As illustrated in FIG. 2, the overhead transmission line can be formed by arranging a conductor made of a plurality of aluminum alloy or aluminum wires (200) around the central tension line (100).

[0042] Specifically, the aluminum wire (200) may be made of 1000 series aluminum such as 1050, 1100, 1200, or an aluminum-zinc alloy, and the tensile strength before heat treatment may be about 15 to 25 kgf / ㎟ and the elongation may be less than about 5%, and the tensile strength after heat treatment may be less than about 9 kgf / ㎟ and the elongation may be about 20% or more.

[0043] In addition, the aluminum wire (200) has a trapezoidal cross-section, and thus, the space factor of the conductor is significantly increased compared to the aluminum wire of a conventional overhead transmission line having a circular cross-section, thereby maximizing the power transmission capacity and power transmission efficiency of the overhead transmission line. For example, the space factor of a conductor including a conventional aluminum wire having a circular cross-section is about 75%, whereas the space factor of a conductor including an aluminum wire having a trapezoidal cross-section can be about 95% or more.

[0044] The aluminum wire (200) above can be formed into a trapezoidal cross-section by confirm extrusion or drawing processing using a trapezoidal die. When the aluminum wire (200) is formed by confirm extrusion, it is naturally heat-treated during the extrusion process, so no separate heat treatment is required. However, when it is formed by a drawing process, a separate heat treatment may be performed subsequently.

[0045] The aluminum wire (200) is heat-treated during the confirmation extrusion process or is heat-treated subsequently after drawing, thereby releasing the area where stress is concentrated and which is formed within the aluminum structure due to twisting during the extrusion or drawing process and which impedes the flow of electrons, thereby improving the electrical conductivity of the aluminum wire (200), and consequently improving the power transmission amount and power transmission efficiency of the overhead transmission line.

[0046] The cross-sectional area and number of the aluminum wire (200) may be appropriately selected according to the specifications of the overhead transmission line. For example, the cross-sectional area of ​​the aluminum wire (200) may be 3.14 to 50.24 ㎟. When an aluminum wire (200) having a trapezoidal cross-section is converted into an aluminum wire having the same cross-sectional area and a circular cross-section, the cross-sectional diameter of the converted aluminum wire may be 2 to 8 mm.

[0047] In addition, the number of the aluminum wires (200) may be, for example, 12 to 40, and preferably, it may have a multi-layer structure including 8 wires in the core layer and 12 wires in the cover layer.

[0048] The above aluminum wire (200) can be heat treated to improve electrical conductivity as described above, but when heat treated in this manner, the surface becomes vulnerable to scratches due to softening, and thus, a number of scratches may be created on the surface of the aluminum wire (200) due to external pressure or impact during the manufacturing, transportation, and installation of the overhead transmission line, and thus, corona discharge may occur during the operation of the overhead transmission line, which may cause high-frequency noise.

[0049] Accordingly, the aluminum wire (200) may have a surface hardness reinforcing layer formed on the surface to suppress the formation of surface scratches. Preferably, the thickness of the surface hardness reinforcing layer may be 5 ㎛ or more, preferably more than 10 ㎛ and 50 ㎛ or less. If the thickness of the surface hardness reinforcing layer is less than 5 ㎛, the surface hardness of the aluminum wire (200) cannot be sufficiently improved, so that a number of scratches may be formed on the surface of the aluminum wire (200) due to external pressure or impact during the manufacturing, transportation, and installation of the overhead transmission line, whereas if the thickness is more than 50 ㎛, the surface hardness reinforcing layer may be locally damaged or cracked when the overhead transmission line is bent, such as when wound on a bobbin.

[0050] Furthermore, the tensile strength of the overhead transmission line is further improved by forming the surface hardness reinforcing layer on the surface of the aluminum wire (200), and as a result, the sag of the overhead transmission line can be further suppressed.

[0051] The above surface hardness reinforcing layer can be formed on the entire surface of the plurality of aluminum wires (200) constituting the overhead transmission line, preferably, it can be formed on the entire surface of each of the aluminum wires (200) present in the uppermost cover layer among the plurality of aluminum wires (200), and more preferably, it can be formed on the outer surface forming the outer periphery of the overhead transmission line among the surfaces of each of the aluminum wires (200) present in the uppermost cover layer.

[0052] The surface hardness reinforcing layer is not particularly limited as long as it can suppress scratch formation by improving the hardness of the surface of the aluminum wire (200), and may include, for example, an aluminum oxide film formed by anodizing treatment, or a plating film such as nickel (Ni), tin (Sn), etc.

[0053] Specifically, the method for anodizing the surface of the aluminum wire (200) may include processes such as cleaning to remove organic contaminants such as oil present on the surface of the aluminum wire (200), rinsing to wash the surface of the aluminum wire (200) with clean water, etching to remove aluminum oxide present on the surface of the aluminum wire (200) with sodium hydroxide, desmutting to dissolve and remove alloy components remaining on the surface of the aluminum wire (200) after etching, rinsing to wash the surface of the aluminum wire (200) again with clean water, anodizing to form a dense and stable aluminum oxide film on the surface of the aluminum wire (200) while applying a voltage of 20 to 40 V, rinsing to wash the surface of the aluminum wire (10) again with clean water, and drying to air dry at room temperature.

[0054] When the surface hardness reinforcing layer includes an aluminum oxide film formed by anodizing, the insulating properties of the aluminum oxide film are excellent, so that power loss can be reduced due to the insulating effect between the aluminum wires (200), and the high radiation properties of the aluminum oxide film can quickly release the Joule heat generated during power transmission into the atmosphere, thereby increasing the current capacity.

[0055] In addition, the surface hardness reinforcing layer may be additionally coated with a polymer resin such as a fluororesin. The polymer resin imparts a superhydrophobic effect to the aluminum oxide film, thereby preventing dust or pollutants in the air from adsorbing on the surface of the overhead transmission line, or preventing snow from accumulating or ice from forming in winter.

[0056] The above surface hardness reinforcing layer may include both an aluminum oxide film and a plating film such as nickel (Ni), tin (Sn), etc., obtained by anodizing. When the above surface hardness reinforcing layer includes both an aluminum oxide film and a plating film, the aluminum oxide film may be disposed on the lower side and the plating film may be disposed on the upper side of the aluminum oxide film, and the thickness ratio of the aluminum oxide film and the plating film may be about 3:1 to 5:1.

[0057] When the thickness ratio of the aluminum oxide film and the plating film is 3:1 to 5:1, the hardness of the surface of the aluminum wire (200) can be sufficiently improved by the aluminum oxide film, which is relatively thick and has a relatively excellent surface hardness improvement effect, and at the same time, when the overhead power line is bent, such as when wound on a bobbin, etc., the local cracks and breakage of the surface hardness reinforcing layer can be effectively suppressed by the plating film, which is arranged on the outside and has a relatively low risk of cracks and breakage due to bending.

[0058] Meanwhile, as illustrated in FIG. 2a, the central tension line (100) may include a core layer (110) made of fiber-reinforced plastic, a detection optical fiber (120) provided inside the core layer (110), etc. Here, a protective tube surrounding the detection optical fiber (120) may be additionally included, and the protective tube may include a metal or polymer resin.

[0059] In addition, as illustrated in FIG. 2b, the central tension line (100) may be formed in a form in which a plurality of wires are joined together in which the core layer (110) is made of fiber-reinforced plastic, and a detection optical fiber (120) may be provided inside each of two or more wires among the plurality of wires, and some of the plurality of detection optical fibers (120) may detect whether the central tension line is broken, and the remaining detection optical fibers may detect other factors such as temperature and temperature.

[0060] FIG. 3 is an example of a cross-sectional view of a center tension line applied to the overhead transmission line illustrated in FIG. 2a, and FIG. 4 is a longitudinal cross-sectional view of a detection optical fiber exposed from a core layer in the center tension line illustrated in FIG. 3.

[0061] As shown in FIGS. 3 and 4, the central tension line (100) may optionally additionally include a cover layer (130) that surrounds the core layer (110). Here, the tensile strength of the central tension line including the detection optical fiber must be 2,800 MPa or more to ensure a sag characteristic that prevents the overhead transmission line from sagging downward.

[0062] When the central tension line (100) additionally includes the cover layer (130), a gap (140) may be formed between the core layer (110) and the cover layer (130). The cover layer (130) may be formed by a method such as conform extrusion of a metal rod such as aluminum or welding of a metal tape such as aluminum, and in particular, since the cover layer (130) may be formed through conform extrusion of an aluminum rod, the cover layer (130) may be formed in a long length, thereby improving productivity and facilitating the formation and control of the gap (140).

[0063] In addition, when confirm extrusion is performed, a cover layer (130) having a continuously formed surface without a joint such as a welded portion can be formed, so that the joint portion can be prevented from being damaged and galvanic corrosion occurring due to bending stress applied to the central tension line (100) during the manufacture, installation, or after installation of the central tension line (100) or the overhead transmission line having the central tension line (100).

[0064] The cover layer (130) and the gap (140) can be formed by extruding a metal material or the like into a tube shape. Specifically, the metal material surrounding the cover layer (130) and having an inner diameter larger than the outer diameter of the cover layer (130) can be formed by extruding it into a tube shape, and then the cover layer (130) can be formed by gradually reducing the diameter, and the size of the gap (140) can be adjusted. For example, the total cross-sectional area of ​​the gap (140) can be about 0.15 to 7.1 ㎟.

[0065] Accordingly, not only can the heat generated during the confirmation extrusion of the aluminum rod for forming the cover layer (130) be suppressed from being transferred to the core layer (110), thereby preventing deterioration of the core layer (110), but also, when bending stress is applied to the central tension wire (100) for the overhead transmission line, the gap (140) causes the core layer (110) and the cover layer (120) to behave separately, thereby allowing most of the bending stress to be applied to the core layer (110) including a fiber-reinforced plastic wire having a relatively high tensile strength, thereby implementing the low-strength characteristics of the overhead transmission line, and at the same time, minimizing the stress applied to the cover layer (130) made of a material such as aluminum having a relatively low tensile strength, thereby suppressing the center tension wire (100) from being damaged when wound on a bobbin, drum, pulley, etc. for manufacturing or installing the overhead transmission line.

[0066] FIG. 5 is a schematic illustration of one end of the overhead transmission line illustrated in FIG. 2a being fastened to a clamp, and FIG. 6 is a schematic illustration of the configuration of the clamps in FIG. 5 being separated from each other, and is one embodiment of a cross-section of the jumper cable illustrated in FIG. 5.

[0067] As illustrated in FIG. 5, a clamp (300) for fixing an overhead transmission line to a tower may include a main body (310) for fixing an aluminum wire (200) of the overhead transmission line, a tension member (320) for fixing a central tension line (100) of the overhead transmission line in a hollow hole inside the clamp main body (310), a jumper terminal (330) for connecting the overhead transmission line and a jumper cable (400) by being fastened to the main body (310), an optical fiber coupler (340) for connecting an optical fiber (122) for detection of a detection member (120) provided in the central tension line of the overhead transmission line and an optical fiber (422) for connection provided in the jumper cable (400), etc.

[0068] As illustrated in Fig. 6a, an overhead transmission line is inserted into the hollow hole of the main body (310), and the central tension line (100) exposed at the end of the overhead transmission line is inserted into the steel sleeve (321) of the tension part (320) and fixed by compression of the steel sleeve (321). In addition, the detection optical fiber (120) provided in the central tension line (100) is exposed at the end of the steel sleeve (321) and is pulled out through the first through hole (322) of the tension part (320), and then a first coupler (341) is connected to the end of the pulled-out detection optical fiber (120).

[0069] In addition, as shown in FIG. 6b, the main body (310) is moved to cover the outside of the tensile portion (320), the optical fiber for detection (120) pulled out through the first through hole (322) is pulled out through the second through hole (312), and the conductor sleeve (311) of the main body (310) is compressed to fix the aluminum wire (200) of the overhead transmission line.

[0070] And, the first jumper terminal (331) shown in FIG. 6c is fastened to the main body (310), and the detection optical fiber (120) pulled out to the outside through the second through hole (312) of the main body (310) can be pulled out to the outside through the third through hole (331a) provided in the first jumper terminal (331), and the detection optical fiber (120) pulled out to the outside through the third through hole (331a) and the first coupler (341) can be covered with a kit case (350), which is a cover.

[0071] In addition, by filling the inside of the kit case (350) with a filler such as silicone or epoxy resin, the optical fiber (120, 422) and coupler (340) located inside the kit case (350) can be protected from external moisture, shock, vibration, etc., and as a result, noise in optical signal transmission and reception by the optical fiber (120, 422) can be minimized or avoided.

[0072] Here, the main body (310), the tensile part (320), and the first jumper terminal (331) can be connected to each other by a bolt that simultaneously penetrates the bolt hole (313) of the main body (310), the bolt hole (323) of the tensile part (320), and the bolt hole (331b) of the first jumper terminal (331).

[0073] In addition, the first jumper terminal (331) is coupled with the second jumper terminal (332) to which the jumper cable (400) is coupled, and the steel tube (421) provided in the jumper cable (400) and the optical fiber for connection (422) mounted inside the steel tube (421) are drawn out to the outside through the fourth through hole (332a) provided in the second jumper terminal (332), and a second coupler (342) is fastened to the end of the optical fiber for connection (422), and the steel tube (421) is extended to the inside of the kit case (350), so that the first coupler (341) and the second coupler (342) are coupled and connected inside the kit case (350).

[0074] Furthermore, only the detection optical fiber (120) may be exposed to the outside by penetrating the through hole (312, 322, 331a), or a portion of the end of the central tension line on which the detection optical fiber (122) is mounted may be exposed to the outside by partially penetrating the through hole (312, 322, 331a). In the case where a portion of the end of the central tension line is exposed to the outside by penetrating the through hole (312, 322, 331a), the detection optical fiber (122) is not directly exposed inside the hollow hole of the main body (310) but is exposed inside the kit case (350), so the detection optical fiber (120) can be protected from external moisture, shock, vibration, etc. inside the hollow hole.

[0075] Meanwhile, the main body (310) is made of a metal material such as aluminum and can be electrically connected to the aluminum wire (200) of the overhead transmission line, and the tensile portion (320) can include a connecting ring (324) that can be fixed to a steel tower. In addition, as illustrated in FIG. 7, the jumper cable (400) can include a conductor (410) including a plurality of wires, a steel tube (421) that replaces at least one of the plurality of wires, a connecting optical fiber (422) mounted inside the steel tube (421), an insulating layer (430) that entirely surrounds the conductor (410) and the steel tube (421).

[0076] In this way, the aluminum wire (200) of the overhead transmission line fixed to one steel tower and the main body (310) of the clamp (300) that compresses the aluminum wire (200) are electrically connected, the main body (310) and the jumper terminal (330) connected thereto are electrically connected, the jumper terminal (330) and the conductor (410) of the jumper cable (400) connected thereto are electrically connected, and the jumper cable (400) is again connected to the clamp connected to the end of another overhead transmission line fixed to the steel tower, so that a plurality of overhead transmission lines can be electrically connected as a whole through a plurality of steel towers via the clamps and jumper cables that are connected to both ends.

[0077] Conventional overhead transmission line clamps are structured so that the internal optical fiber cannot be exposed to the outside after being fastened to the overhead transmission line, making it impossible to connect an optical transmission device or optical detection device to the optical fiber. As a result, it was impossible to detect damage to the central tension wire after the overhead transmission line was installed on the tower.

[0078] However, since the clamp according to the present invention allows the optical fiber inside the overhead transmission line to be exposed to the outside even after being fastened to the overhead transmission line, not only is it possible to connect an optical transmission device or an optical detection device, but it also allows the optical fiber of the entire overhead transmission line to be connected via a jumper cable, so that it is possible to accurately and easily detect whether the central tension wire of the entire overhead transmission line is damaged even during operation of the overhead transmission line.

[0079] As described above, when multiple optical fibers for detection are provided, multiple optical fibers for connection (422) are also provided in the jumper cable (400), and multiple optical fiber couplers (340) for connecting the multiple optical fibers for detection (122) and the multiple optical fibers for connection (422) are also provided and can be positioned inside the kit case (350).

[0080] Accordingly, according to the overhead transmission line system according to the present invention, after the main body (310) and the tension part (320) of the clamp are fastened to each of the two ends of the overhead transmission line at an above-ground work site such as a factory, the detection optical fiber (120) of the central tension line (100) is drawn out through the first and second through holes (312, 322), and the first coupler (341) is fastened to the end of the detection optical fiber (122), and the kit case (350) can be fastened to the main body (310) so as to cover the first coupler (341) to protect it.

[0081] In this way, overhead transmission lines with clamps already attached to both ends are transported between adjacent steel towers. The transport of the overhead transmission line can be performed by connecting a separate extension line to the connecting ring (322) of the tensile portion (320) of the clamp (300) at one end of the overhead transmission line, and then pulling the extension line over the steel tower.

[0082] Then, the worker connects the connecting ring (324) of the tensile portion (320) of the clamp (300) on the tower to the tower, separates the kit case (350) from the main body (310), and then connects the first jumper terminal (331) of the jumper terminals (330) to the main body (310).

[0083] Next, the second jumper terminal (332) connected to the jumper cable (400) is connected to the first jumper terminal (331), and the connecting optical fiber (422) mounted inside the steel tube (421) is drawn out through the fourth through hole (332a) of the second jumper terminal (332), a second coupler (342) is fastened to the end, and the second coupler (342) is connected to the first coupler (341).

[0084] When the connection is completed in this way, the kit case (350) is connected to the first jumper terminal (331) so that the first coupler (341) and the second coupler (342) connected inside the kit case (350) are positioned, and then the empty space inside the kit case (350) is filled with a filler such as silicone or epoxy resin.

[0085] Accordingly, the method for constructing an overhead transmission line system according to the present invention is such that the overhead transmission line is transported to the installation location with the clamp fastened to the overhead transmission line, so that the worker does not need to fasten the clamp on the tower, thereby improving the workability of the overhead transmission line installation work and the safety of the worker, and the work of connecting the optical fiber (122) of the detection unit (120) provided on the overhead transmission line as a whole is easy, so that even after installing the overhead transmission line on the tower, it is possible to easily and accurately detect whether the center tension line is damaged, etc.

[0086] Figure 8 is a schematic diagram showing an example of detecting damage to a central tension line using an OTDR (Optical Time Domain Deflectometers) method.

[0087] Since there is no need to connect a jumper cable (400) to the clamp (300) connected to the end of the overhead transmission line arranged at both ends among the multiple overhead transmission lines that are connected as a whole through multiple steel towers, there is no need to provide a jumper terminal (330), and a measuring device such as an OTDR or DTS is connected to the optical fiber for detection exposed to the outside through the first through hole (311) in the main body (310) of the clamp (300).

[0088] Specifically, as illustrated in FIG. 8, an optical signal is input to an optical fiber exposed at one end of a cable through an OTDR meter while connecting the optical fiber to an optical fiber connector cable, and an optical signal reflected and returned from the other end of the optical fiber is recovered, thereby measuring optical loss due to a break in the optical fiber, etc., and thereby measuring whether a break in the optical fiber, etc. has occurred and its location. Since such a break in the optical fiber, etc. is caused by a break in the central tension line, etc., based on the measured value for the optical fiber, it is possible to detect not only whether the central tension line is broken but also the location of the break.

[0089] That is, in the case of a normal central tension line, a change in signal size occurs at the end of the central tension line where clamping has occurred, but when a break occurs in the middle of the central tension line, a change in signal size occurs at the location where the break occurred. In other words, the location where the break occurred can be recognized as the end of the central tension line. Therefore, by recognizing the change in signal size and the location where the change occurred, it is possible to detect whether the central tension line is broken and the location of the breakage.

[0090] While this specification has described preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims below. Therefore, any modified implementation that fundamentally includes the elements of the claims should be considered within the technical scope of the present invention.

Claims

1. A clamp for overhead transmission lines for installing overhead transmission lines including a central tension line and aluminum wires arranged around the central tension line on a steel tower, A main body having a hollow hole into which the above-mentioned overhead transmission line can be inserted and fixing the aluminum wire of the overhead transmission line inserted into the hollow hole; and It includes a tension member having a connecting link for fixing the central tension line of the overhead transmission line inserted into the hollow hole and connecting the overhead transmission line to the steel tower. A clamp for an overhead transmission line, wherein the main body and the tension portion are provided with a through hole through which a detection optical fiber provided in the central tension line can pass through and be drawn out to the outside.

2. In paragraph 1, It additionally includes a jumper terminal that is fastened to the above main body and to which a jumper cable is connected, A clamp for an overhead transmission line, characterized in that the optical fiber for detection is connected to the optical fiber for connection provided in the jumper cable.

3. In paragraph 2, The above jumper terminal includes a first jumper terminal connected to the main body and a second jumper terminal connected to the jumper cable, A clamp for an overhead transmission line, characterized in that the first jumper terminal and the second jumper terminal are connected.

4. In paragraph 3, The above first jumper terminal is provided with a through hole through which the optical fiber for detection can pass and be drawn out to the outside, A clamp for an overhead transmission line, characterized in that the second jumper terminal has a through hole through which the optical fiber for connection can pass and be drawn out to the outside.

5. In Article 4, A clamp for an overhead transmission line, characterized in that an optical fiber coupler is provided at each of the drawn ends of the optical fiber for detection and the optical fiber for connection to be coupled to each other.

6. In paragraph 5, A clamp for overhead transmission lines, characterized in that it further includes a kit case that covers the optical fiber coupler and is connected to the first jumper terminal.

7. In paragraph 6, A clamp for an overhead transmission line, characterized in that the empty space inside the kit case is filled with a filler.

8. In paragraph 7, A clamp for an overhead transmission line, characterized in that the above filler is silicone or epoxy resin.

9. In any one of paragraphs 1 to 8, A clamp for an overhead transmission line, characterized in that a portion of the end of the central tension line is pulled out through the through hole together with a detection optical fiber provided on the central tension line.

10. In any one of paragraphs 6 to 8, The above jumper cable comprises a steel tube and a connecting optical fiber mounted inside the steel tube, A clamp for overhead transmission lines, characterized in that the steel tube is drawn out through the through hole of the second jumper terminal and inserted into the inside of the kit case.

11. Multiple overhead transmission lines; and An overhead transmission line system comprising an overhead transmission line clamp according to any one of claims 1 to 8, which is fastened to both ends of each of the plurality of overhead transmission lines.

12. In paragraph 11, A clamp for overhead transmission lines, characterized in that the above-mentioned plurality of overhead transmission lines include a central tension line in the form of a plurality of wires joined together.

13. In paragraph 12, A clamp for an overhead transmission line, characterized in that a detection optical fiber is provided inside each of two or more of the plurality of small wires, some of the detection optical fibers detect whether the central tension line is broken, and the remaining some of the detection optical fibers detect other factors.

14. A step of attaching a clamp for an overhead transmission line according to any one of clauses 1 to 8 to both ends of the overhead transmission line. A step of transporting an overhead transmission line with clamps attached to both ends to a construction location; A step of connecting the connecting ring of the tensile part in the above clamp to the temporary position; A step of connecting a jumper terminal connected to a jumper cable to the main body in the above clamp, and A method for installing an overhead transmission line, comprising a step of connecting an optical fiber for detection provided in a central tension line of the overhead transmission line and an optical fiber for connection provided in the jumper cable.

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