KR20230032044A - Shield cable for electric railway - Google Patents

Abstract

The present invention relates to a shield cable for an electric railway. More specifically, the present invention relates to a shield cable for an electric railway, wherein a plurality of copper wires are laterally wound to form a shielding layer, thereby shielding electromagnetic noise. According to the laterally wound copper wire shielding structure of the shielding cable for an electric railway according to the present invention, an electromagnetic wave shielding function can be provided to a railway control cable by replacing an existing dual tape shielding structure. Particularly, even if a necessary shielding coefficient or cable dimensions are varied, a shielding layer can be formed with the same process difficulty by modifying the copper wire number of the laterally wound copper wire structure and the diameter thereof alone, thereby improving costs and efficiency for forming a shielding structure compared with an existing dual tape shielding structure.

Description

Shielded cable for electric railway {SHIELD CABLE FOR ELECTRIC RAILWAY}

The present invention relates to shielded cables for electric railways. More specifically, the present invention relates to a shielded cable for electric railways in which electromagnetic noise is shielded by forming a shielding layer in which a plurality of copper wires are cross-wound.

Electrification of railroads is expanding, and communication and signal transmission can be performed to share train operation information and control information with a central operation system. In such an electrified railway power supply system, catenary lines for supplying power to rolling stock are installed along the railroad tracks, and cables for bi-directional communication or transmission of signals in a specific direction may be installed along the railroad tracks.

AC power may be used in a power supply system of an electrified wide-area railway, and in this case, electromagnetic induction may occur due to AC power in addition to electrostatic interference due to DC power. Unlike DC electrostatic interference, such electromagnetic induction interference may affect a cable signal by penetrating a metal tape having low electrical resistance even if it is wound around the cable, so a separate shielding means may be further required.

Regarding a cable structure for shielding electromagnetic induced interference due to alternating current, reference may be made to Patent Publication No. 10-2014-0060941 (Patent Document 1). Patent Document 1 proposes a structure in which a double shielding layer in the form of a corrugated tape is formed for electromagnetic shielding, but such a double-tape shielding structure requires a change in the tape thickness dimension and the tape forming process whenever the outer diameter of the cable is changed. As a result, it may have limitations in terms of process cost and difficulty.

Patent Document 1: Republic of Korea Patent Publication No. 10-2014-0060941

The technical problem to be solved by the present invention is to construct a shielding layer by cross-winding a plurality of copper wires in order to overcome the limitations of the conventional double tape shielding structure, and adjust the number of copper wires and the outer diameter to achieve the target shielding performance It is to provide a shielded cable for electric railways having a cross-wound shielding structure capable of

As a means for solving the above-mentioned technical problem,

The present invention provides a shielded cable for electric railways, comprising: a cable core including at least one insulated core wire made of a conductor and an insulator surrounding the conductor; an insulating layer surrounding the cable core; a shielding layer surrounding the heat insulating layer and formed by cross-winding a plurality of copper wires; an inner sheath surrounding and covering the shielding layer; an outer layer surrounding the inner sheath and protecting the shielded cable; and an outer sheath surrounding and covering the outer sheath, wherein the shielded cable has a shielding factor of 3% to 40% defined by the equation below.

<mathematical expression>

Shielding factor (%) = (Induced voltage (Ev) / Applied voltage (Em)) * 100

In addition, the present invention provides a shielded cable for electric railway, characterized in that the number of copper wires is 6 to 40, and the outer diameter of the copper wires is 0.9 mm to 2.0 mm.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the outer layer is formed by cross-winding a steel tape in one or more layers.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the steel tape has a thickness of 0.4 mm to 0.8 mm.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the steel tape contains nickel or silicon.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the inner sheath is made of any one of polyethylene (PE), polyvinyl chloride (PVC) and other polyolefin-based (PO) resins.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the heat insulating layer includes at least one insulating paper and at least one metallized paper.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the insulation layer further comprises a sheath made of a polymer resin.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the heat insulating layer is constructed by cross-winding a foamed polyolefin tape.

In addition, the present invention provides a shielded cable for electric railway, characterized in that the outer sheath is made of any one of polyethylene (PE), polyvinyl chloride (PVC) and other polyolefin-based (PO) resins.

In addition, the present invention provides a shielded cable for electric railways, characterized in that the cable core further includes an intervening material made of a polymer material or a tape surrounding the cable core.

According to the cross-wound copper wire shielding structure of the shielded cable for electric railways according to the present invention, it is possible to provide electromagnetic shielding performance in railway control cables by replacing the conventional double tape shielding structure. In particular, since the required shielding coefficient can be satisfied by freely adjusting the number and diameter of the copper wires constituting the shielding layer, it is possible to form a shielding layer that can satisfy shielding performance with the same process difficulty regardless of product size. Therefore, the cost and efficiency of forming the shielding structure can be improved compared to the conventional double tape shielding structure.

The accompanying drawings are intended to explain the contents of the present invention in more detail to those skilled in the art, but the technical spirit of the present invention is not limited thereto.
1 is a diagram for explaining elements constituting a shielded cable for an electric railway according to some embodiments.
2 is a diagram for explaining a method in which a plurality of copper wires constituting a shielding layer form a cross-wound shielding structure according to some embodiments.
3 is a diagram for explaining a form in which cable cores are configured according to the number of one or more insulated core wires according to some embodiments.
4 is a diagram for explaining detailed specifications of components of a shielded cable for electric railways according to some embodiments.
5 is a diagram for explaining the number of copper wires and the outer diameter of copper wires adjusted to implement a target shielding factor in a cable having two insulated core wire pairs (2P(1Q)) according to some embodiments.
6 is a diagram for explaining the number of copper wires and the outer diameter of copper wires adjusted to implement a target shielding factor in a cable having four insulated core wire pairs (4P(2Q)) according to some embodiments.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description is only for specifying the embodiments, and is not intended to limit or limit the scope of rights according to the present invention. What a person skilled in the art can easily infer from the detailed description and examples of the present invention should be construed as belonging to the scope of the present invention.

The terms used in the present invention have been described as general terms widely used in the technical field related to the present invention, but the meanings of the terms used in the present invention are the intentions of technicians working in the field, the emergence of new technologies, examination standards or precedents. etc. may vary. Some terms may be arbitrarily selected by the applicant, and in this case, the meanings of the arbitrarily selected terms will be described in detail. Terms used in the present invention should be interpreted as meanings reflecting the overall context of the specification, not just dictionary meanings.

Terms such as 'consisting' or 'comprising' used in the present invention should not be construed as necessarily including all of the components or steps described in the specification, and if some components or steps are not included, and when additional components or steps are further included, it should also be construed as intended from the term.

Terms including ordinal numbers such as 'first' or 'second' used in the present invention may be used to describe various components or steps, but the components or steps should not be limited by ordinal numbers. . Terms containing ordinal numbers should only be construed to distinguish one component or step from other components or steps.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A detailed description of matters widely known to those skilled in the art will be omitted.

1 is a diagram for explaining elements constituting a shielded cable for an electric railway according to some embodiments.

Referring to FIG. 1, a shielded cable 100 for electric railway includes a cable core 110, an insulating layer 120, a shielding layer 130, an inner sheath 141, an outer layer 151, and an outer sheath 152. can include However, it is not limited thereto, and other general-purpose elements may be further included in the cable 100.

The cable 100 may be utilized to transmit various control signals in a track circuit using rails of an electric railway as part of a circuit for exchanging signals. Track circuit signals transmitted by the cable 100 may be signals in the audible frequency (AF) region, and since AC power is used in electric railways, the cable 100 requires a shielding structure to counteract AC electromagnetic induction noise can be done with

As one example, the cable 100 may be a shielded cable for electric railways for signal transmission. That is, the cable 100 may be a cable that is for signals, has a star quad construction, insulation of the core wire is polyethylene, and electromagnetic noise shielding is copper wire shielding. However, if necessary, the cable 100 may be implemented in a different type than the above example.

The cable core 110 may include one or more insulated core wires 112 made of a conductor 113 and an insulator 114 surrounding the conductor 113 . The insulating core wire 112 may be formed in pairs, and the pairs of the insulating core wire may be combined to form a star quad construction shape. However, this structure is one embodiment, and various arrangements of the insulated core wire 112 are possible according to usage and standards.

The cable core 110 may transmit various control signals in the track circuit. Signals transmitted through the cable core 110 may be signals in an audible frequency (AF) region or may be AC signals by an AC power supply. Accordingly, a structure for shielding electromagnetic interference caused by AC signals in other cables around the cable core 110 may be required.

The conductor 113 may be a copper wire having an outer diameter of 1.0 mm to 1.4 mm according to KS C 3101 (electric copper wire). The conductor 113 should not have a connection point as much as possible, and in unavoidable cases, it may be welded by non-acidic silver alloy. The insulator 114 may be composed of colored polyethylene and may be coated on the conductor 113 to a thickness of about 0.4 mm to 0.8 mm.

In order to prevent the insulated core wires 112 included in the cable core 110 from being disturbed, an inclusion made of a polymer material such as polyethylene (PE) may be inserted into the center of the core. Alternatively, the insulating core wires 112 may be fixed by taping using a polyester tape or the like.

The insulation layer 120 may surround the cable core 110 . Due to the thermal insulation effect of the thermal insulation layer 120, the degree to which the internal temperature of the cable core 110 is affected by the external temperature of the cable 100 may be reduced.

For example, the heat insulating layer 120 may include one or more insulating papers and one or more metallized papers 121, and preferably, 4 sheets of insulating paper 121 for communication cables wound around the cable core 110 and 0.15 mm It may include one sheet of metalized paper 121 having a thickness. In addition, a heat insulating sheath 122 made of a polymer resin such as polyethylene may be added to prevent a space from being formed inside the heat insulating layer 120 . In addition, the heat insulating layer 120 may be formed by winding one or more foamed polypropylene tapes.

The shielding layer 130 surrounds the heat insulating layer 120 and is composed of a plurality of copper wires to shield electromagnetic noise and the like in a spiral shielding method. The number of copper wires and outer diameters of the plurality of copper wires may be adjusted to implement a target shielding coefficient capable of satisfying shielding performance.

Here, the shielding factor may be defined as a ratio of the induced voltage (Ev) induced in the cable to the applied voltage (Em), and may be expressed by the following equation.

<mathematical expression>

Shielding factor (%) = (Induced voltage (Ev) / Applied voltage (Em)) * 100

The shielding coefficient may vary depending on the number of copper wires, the outer diameter of the copper wires, and the thickness of the exterior layer, and may preferably satisfy a range of 3% to 40% to satisfy shielding performance.

The shielding layer 130 may be formed of concentric copper wires wound on the heat insulating layer 120 in a spiral shape. The number of copper wires constituting the shielding layer 130 may be 6 or more to 40 or less, and the outer diameter (thickness) of each copper wire may be 0.9 mm to 2.0 mm. Additionally, a binder tape for fixing the copper wires of the shielding layer 130 may be wound.

The number of copper wires and the value of the outer diameter of the plurality of copper wires constituting the shielding layer 130 may be varied according to the variation of the shielding coefficient to satisfy the target shielding performance. That is, when a higher shielding factor is required, the number of copper wires or the numerical value of the outer diameter of the copper wire can be set higher when manufacturing the cable 100, and when a lower shielding factor is required, when manufacturing the cable 100, the number of copper wires can be set higher. The number or outer diameter of the copper wire may be set lower.

The inner sheath 141 may be made of a polymer resin and cover the shielding layer 130 . The inner sheath 141 may be made of any one of polyethylene (PE), polyvinyl chloride (PVC), and other polyolefin-based (PO) resins. Preferably, the inner sheath 141 may be a black polyethylene (PE) sheath having a thickness of 1.3 mm to 1.7 mm. A tape 142 made of rubber, cotton, or nonwoven fabric may be further included in the inner sheath 141 .

The outer layer 151 may serve to protect the shielded cable while surrounding the inner sheath 141 . The thickness of the exterior layer 151 is a factor that can affect the shielding coefficient, and like the number of copper wires and the outer diameter of the copper wires in the shield layer 130, the thickness of the exterior layer 151 determines the required shielding performance. Depending on the range, the range may vary.

Preferably, the exterior layer 151 may be formed by cross-winding a steel tape into one or more layers, and the thickness of the steel tape may be 0.4 mm to 0.8 mm. The steel tape may have a structure in which two sheets are wound so as to be 1/3 apart. In addition, rigidity may be reinforced by applying a steel tape made of a material containing an alloy element such as silicon or nickel to the steel tape.

The outer sheath 152 surrounds the outer sheath 151 and may be the final outer sheath of the cable 100 . The outer sheath 152 may be made of any one of polyethylene (PE), polyvinyl chloride (PVC), and other polyolefin-based (PO) resins, and may be preferably made of low-toxic flame retardant polyolefin.

As described above, the cable 100 including the cable core 110, the insulation layer 120, the shielding layer 130, the inner sheath 141, the outer layer 151 and the outer sheath 152 is audible for AC electric railway It can be utilized to control the frequency track circuit. In particular, even if the cable 100 is used for AC electric railway by the shielding layer 130, electromagnetic noise can be prevented from affecting the cable signal, and the plurality of copper wires constituting the shielding layer 130 and the sheath By setting the detailed specifications of the layer, a shielding factor of a specific value required for the cable 100 can be achieved.

2 is a diagram for explaining a method in which a plurality of copper wires constituting a shielding layer form a cross-wound shielding structure according to some embodiments.

Referring to FIG. 2, there is shown a cross-winding structure of the copper wire of the shielding layer 130 included in the audio frequency track circuit control cable 100 for AC electric railway. The shielding layer 130 may be composed of a plurality of copper wires 131, and the plurality of copper wires 131 may surround the cable core 110 and the heat insulating layer 120 in a concentric spiral shape. there is.

The shielding performance, that is, the shielding coefficient of the cable 100, may be determined according to the detailed structure such as the number and outer diameter of the plurality of copper wires 131 forming the shielding layer 130 and the thickness of the outer layer 151. As the number of the plurality of copper wires 131 in the shielding layer 130 increases, as thicker copper wires are used, and as the thickness of the exterior layer 151 increases, higher shielding performance can be provided.

As such, the method of adjusting the shielding coefficient by changing the detailed structure of the plurality of copper wires 131 and the exterior layer 151 may be advantageous in terms of process difficulty and processing cost when compared to the conventional double tape shielding structure. That is, unlike the prior art, it is possible to change the shielding coefficient by changing only the number of copper wires, the outer diameter, or the thickness of the outer layer without changing the thickness of the shielding structure, so that the overall thickness of the cable 100 is not changed, so the process difficulty can be maintained constant. And, the cable 100 can be produced with an optimal material cost.

3 is a diagram for explaining a form in which cable cores are configured according to the number of one or more insulated core wires according to some embodiments.

Referring to FIG. 3 , the insulating core wires 112 may be formed in pairs, and two pairs of insulating core wires may be combined to form a star quad construction shape 320 . In addition, the number of pairs of the insulated core wire may be 4, 6, 8, 10, 14, 20 or 28, and the insulated core wire 112 may be arranged in various ways according to usage and standards. The illustrated structure is an example, and various arrangements other than the illustrated structure are possible, of course.

4 is a diagram for explaining detailed specifications of components of a shielded cable for electric railways according to some embodiments.

Referring to FIG. 4 , a table 400 for explaining detailed specifications of components of a shielded cable 100 for electric railway is shown.

In table 400, each item of the cable 100 depends on whether the cable core 110 consists of two insulated core wire pairs (2P (1Q)) or four insulated core wire pairs (4P (2Q)). Exemplary detailed dimensions may be indicated. Commonly in the 2P (1Q) cable and the 4P (2Q) cable, the diameter (outer diameter) of the conductor 113 may be 1.2 mm, the thickness of the insulator 114 may be 0.6 mm, and the outer layer 151 may be Two sheets of steel tape (steel sheathing) having a thickness of 0.5 mm may be provided.

Other than that, the detailed dimensions of the items of the cable 100, including the quad array in the 2P (1Q) cable and the 4P (2Q) cable, may be different from each other. In general, as shown in table 400, a 4P (2Q) cable 100 may be formed with larger dimensions than a 2P (1Q) cable 100.

The cable specifications described in table 400 are an example, and can be changed in various forms depending on the purpose and requirements of the cable.

5 is a diagram for explaining the number of copper wires and the outer diameter of copper wires adjusted to implement a target shielding factor in a cable having two insulated core wire pairs (2P(1Q)) according to some embodiments.

Referring to FIG. 5 , a table 500 for describing the number of copper wires and the outer diameter of copper wires adjusted to implement a target shielding factor in a 2P (1Q) cable is shown.

In the table 500, the measurement result of the shielding coefficient (K) for the combination of the number of copper wires and the outer diameter of the copper wires, that is, (14ea * 1.2 mm), may be displayed. The shielding factor (K) may be expressed as a ratio of the voltage (Ev) induced in the cable 100 to the applied voltage (Em). On the other hand, regarding the measurement standard of the shielding factor (K), as shown in table 500, the shielding factor (K) for an applied voltage of 100V/km at 60Hz may be the standard. At this time, the outer layer 151 ) may be two nickel steel strips having a thickness of 0.6 mm.

Specifically, when the outer layer 151 is two nickel steel strips with a thickness of 0.6 mm, the number of copper wires is 14, and the outer diameter of the copper wire is 1.2 mm, 2P (1Q) cable 100 having two insulated core wire pairs In the case of , it may have a shielding factor of 14%.

6 is a diagram for explaining the number of copper wires and the outer diameter of copper wires adjusted to implement a target shielding factor in a 4P (2Q) cable having four insulated core wire pairs according to some embodiments.

Referring to FIG. 6 , a table 600 for describing the number of copper wires and the outer diameter of copper wires adjusted to implement a target shielding factor in a 4P (2Q) cable is shown.

In the table 600, the measurement result of the shielding coefficient (K) for a combination of the number of copper wires and the outer diameter of the copper wires, that is, (26ea * 1.2 mm) may be displayed.

As in the table 500 of FIG. 5, in the table 600, the shielding factor (K) can be expressed as a ratio of the voltage (Ev) induced in the cable 100 to the applied voltage (Em), and 100V of 60Hz A shielding coefficient (K) for an applied voltage of /km may be a criterion for determining shielding performance. In addition, the exterior layer 151 may be two sheets of nickel steel strips having a thickness of 0.6 mm.

Specifically, when the outer layer 151 is two nickel steel strips with a thickness of 0.6 mm, the number of copper wires is 26, and the outer diameter of the copper wire is 1.2 mm, the 4P (2Q) cable 100 having four insulated core wires In this case, it may have a shielding factor of 9% by (26ea * 1.2mm).

Although the embodiments of the present invention have been described in detail above, the scope of rights according to the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention described in the following claims are also the present invention. It should be interpreted as being included in the scope of rights according to

100: shielded cable for electric railway
110: cable core 111: quad
112: insulated core wire 113: conductor
114: insulator 120: insulation layer
121: insulating paper/metalized paper 122: insulating sheath
130: shielding layer 131: plurality of copper wires
141: inner sheath 142: tape
151: outer layer 152: outer sheath

Claims (11)

In the shielded cable for electric railway,
A cable core including at least one insulated core wire made of a conductor and an insulator surrounding the conductor;
an insulating layer surrounding the cable core;
a shielding layer surrounding the heat insulating layer and formed by cross-winding a plurality of copper wires;
an inner sheath surrounding and covering the shielding layer;
an outer layer surrounding the inner sheath and protecting the shielded cable; and
An outer sheath surrounding and covering the exterior layer,
The shielded cable is a shielded cable for electric railways, characterized in that the shielding coefficient defined by the equation below is 3% to 40%.
<mathematical expression>
Shielding factor (%) = (Induced voltage (Ev) / Applied voltage (Em)) * 100
According to claim 1,
The number of the copper wire is 6 to 40, and the outer diameter of the copper wire is 0.9 mm to 2.0 mm, characterized in that, a shielded cable for electric railway.
According to claim 2,
The shielded cable for electric railway, characterized in that the outer layer is formed by cross-winding a steel tape in one or more layers.
According to claim 3,
Characterized in that the steel tape has a thickness of 0.4 mm to 0.8 mm, shielded cable for electric railway.
According to claim 4,
The shielded cable for electric railway, characterized in that the steel tape contains nickel or silicon.
According to claim 1,
The inner sheath is made of any one of polyethylene (PE), polyvinyl chloride (PVC) and other polyolefin-based (PO) resins.
According to claim 1,
The shielded cable for electric railway, characterized in that the insulation layer comprises at least one insulating paper and at least one metallized paper.
According to claim 7,
The shielded cable for electric railway, characterized in that the insulation layer further comprises a sheath made of a polymer resin.
According to claim 1,
The shielded cable for electric railways, characterized in that the insulation layer is constructed by cross-winding a foamed polyolefin-based tape.
According to claim 1,
The outer sheath is characterized in that made of any one of polyethylene (PE), polyvinyl chloride (PVC) and other polyolefin-based (PO) resins, shielded cables for electric railways.
According to claim 1,
The cable core comprises an inclusion made of a polymer material or further comprises a tape surrounding the cable core.

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