KR101977966B1 - Mylar tape of high voltage cable for underground - Google Patents

Abstract

The present invention provides a copper mylar tape capable of improving watertightness, flexibility, and shielding of an underground high voltage cable.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high-

The present invention relates to a mylar tape for underground embedded high voltage cables.

Generally, a coaxial power cable means a cable in which a conductor in the center is insulated with a cross-linked polyethylene, and further, the outside is covered with polyethylene or PVC.

The power cable can be divided into a low voltage of 750V, a high voltage of 750V to 7,000V, a special high voltage of 7,000V to 66,000V, and an ultra high voltage of 66,000V to 220,000V. Generally, , 229 kV) and ultra high voltage such as 154,000 V or 765,000 V flows in the transmission tower. Therefore, for safety, proper cable design is made according to the voltage to be used (or transmission voltage).

The power cable can be divided into an underground cable and a working cable. Underground cable is a cable embedded in the underground, and a processing cable is a cable installed on the pole. Since the processed cable is exposed to the outside, it is affected by the surrounding environment (eg, sunlight, wind, rain, snow, lightning, branches, etc.) If the insulation breaks down, there is a danger of a short circuit, and a large current (that is, a fault current) flows instantaneously at the time of short-circuit, so that the cable (cable) may melt or fire may occur. In addition, due to the controversial hazard of electromagnetic waves, high-voltage cables are installed in the ground.

There are two types of high-voltage cables embedded in the ground. One is a tunnel made of concrete, which is embedded in the ground. A shelf is installed inside the tunnel so that underground distribution lines can be placed. The other method is to lay a protective pipe made of concrete material or synthetic resin in the ground and to store the underground distribution line inside the buried protective pipe.

In both methods, the underground distribution line is installed in the space separated from the external contact in the ground. Sudden rainfall or flood can cause sudden rainfall. In addition, the inflow of water due to damage of underground tunnel or protection pipe is uneven Lt; / RTI > If the drainage of the water introduced by the environment separated from the external contact is not smooth, the underground distribution line may come into contact with the water, and in the worst case, the underground distribution line may be immersed in the water. In such a case, a short circuit may occur due to contact between the electric wire and water, and there is a risk that a person is electrocuted.

Also, since the underground distribution line is located in the underground tunnel, there is a problem that it is difficult to suppress the fire promptly when a fire occurs due to leakage current or other reasons in the underground distribution line.

When the underground distribution line is placed in the ground for a long time, the insulation may be destroyed due to aging due to the influence of the environment in the underground tunnel. If the insulation breaks down, there is a danger of a short circuit, and a large current (that is, a fault current) flows instantaneously at the time of short-circuit, so that the cable (cable) may melt or fire may occur.

At this time, the fault current does not flow only through the conductor but also through the ground to the shielding layer of the cable. The shielding layer can also damage the entire cable if it does not tolerate a certain amount of short-circuit capacity (fault current and breakdown duration that it can sustain).

In the past, neutralization was used to prepare for failure. However, in the case of the neutral wire system, inserting the wire into a three-core cable, for example, a three-core cable for transmission and distribution of a three-phase current, has a problem that the insulator is pressed, installation and operation are difficult, and shielding performance is deteriorated.

The main object of the present invention is to provide a copper mylar tape for an underground embedded high-voltage cable which is easy to install underground high-voltage cable, can prevent flooding into a cable, and can prevent rupture due to a short in the cable will be.

According to an embodiment of the present invention, a copper Mylar tape for an underground embedded high-voltage cable includes a core portion formed of three conductor cores and a core portion surrounding the core portion. In the underground embedded high-voltage cable, A copper mylar tape for an underground embedded high voltage cable, comprising: a first copper layer adjacent to the core portion; a second copper layer adjacent to the sheath layer; and a second copper layer adjacent to the core portion between the first copper layer and the second copper layer An antioxidant layer formed on one surface of the first copper foil layer facing the core portion; and a second copper foil layer on the second copper foil layer facing the second copper foil layer, And a laminate layer formed on one side of the copper foil layer, wherein the laminate layer is melt-bonded to the second copper foil layer on one side and bonded to the sheath layer on the other side, It is possible to prevent water from penetrating into the core portion inside the base laminate layer.

In the present invention, the laminate layer may comprise 70% by weight of PE, 20% by weight of a binder and 10% by weight of an acid.

In the present invention, the laminate layer may be made of ethylene acrylic acid (EAA)

In the present invention, the laminate layer may be exposed to an acid at a temperature of 60 ° C or higher to be melt-adhered to the second copper foil layer.

In the present invention, the laminate layer may be partially melted and bonded to the sheath layer during the sheath layer forming process.

In the present invention, the thickness of the base layer may be greater than the thickness of the first copper layer and the thickness of the second copper layer, and may be less than the sum of the thickness of the first copper layer and the thickness of the second copper layer .

According to an embodiment of the present invention, it is possible to increase the resilience of the roll-releasing cable for installation after the drum is wound, to facilitate the laying, and to improve the adhesion with the sheath layer to prevent flooding into the inside of the cable, It is possible to have a strength capable of preventing rupture caused by the rupture.

1 is a cross-sectional view schematically showing a copper Mylar tape for an underground embedded high voltage cable according to an embodiment of the present invention.
Fig. 2 is a perspective view schematically showing an underground high-voltage cable including the copper mylar tape of Fig. 1. Fig.
3 is a cross-sectional view schematically showing an underground embedded high-voltage cable of FIG.
4 to 7 are cross-sectional views of a copper mylar tape for an underground embedded high voltage cable according to an embodiment of the present invention.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are shown enlarged from the actual for the sake of clarity of the present invention. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In this application, the terms "comprise," "include," or "having" are intended to specify that there are stated features, numbers, steps, operations, elements, parts or combinations thereof, But do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Also, where a portion such as a layer, film, region, plate, or the like is referred to as being "on" another portion, this includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. In the present specification, when a part of a layer, a film, an area, a plate, or the like is formed on another part image on, the forming direction is not limited to an upper part but includes a part formed in a side or a lower direction . On the contrary, where a section such as a layer, a film, an area, a plate, etc. is referred to as being "under" another section, this includes not only the case where the section is "directly underneath"

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view schematically showing a copper Mylar tape for an underground embedded high voltage cable according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing a submerged high-voltage cable including the copper mylar tape of FIG. 1, and FIG. 3 is a cross-sectional view schematically showing the submerged high-voltage cable of FIG.

1 to 3, a copper mylar tape 100 for an underground embedded high voltage cable according to an embodiment of the present invention is used for wrapping three conductor cores in an underground embedded high voltage cable having three conductor cores .

Specifically, the underground high-voltage cable 10 is in close contact with the first conductor core wire 10a, the second conductor core wire 10b, and the third conductor core wire 10c in a triangular shape. The copper mylar tape 100 is wrapped around the outer peripheries of the three closely connected conductor wires 10a, 10b and 10c in a longitudinal direction so as to be stretched (that is, not stretched and straightened) so that the conductor wires 10a, 10b and 10c ) Can be firmly held so that the cross-section thereof can have a triangular shape. It is possible to prevent the three conductor cores 10a, 10b, and 10c from being shaken by keeping the conductor wires 10a, 10b, and 10c in close contact with each other by firmly holding the triangular shape of the copper mylar tape 100, It is possible to prevent a phenomenon that the braided copper wire is pushed or tilted to one side in the shielding portion 18 which surrounds the outer side of the conductor core wires 10a, 10b, 10c.

The inner surface of the copper mylar tape 100 can be in contact with the shielding portions 18 disposed outside of the conductor cores 10a, 10b and 10c, respectively. The inner surface of the copper mylar tape 100 contacts the shielding portion 18 formed at the outermost portion of the first conductor core wire 10a, the second conductor core wire 10b and the third conductor core wire 10c Thereby preventing an induced current generated in accordance with each phase-to-phase unbalanced current (that is, a three-phase unbalanced current flowing through each core wire) from being deflected.

A sheath layer 20 may be formed on the outer side of the copper mylar tape 100. The sheath layer 20 may cover the outside of the copper mylar tape 100 as the outermost layer of the underground high voltage cable 10.

The copper mylar tape 100 and the sheath layer 20 can be bonded. Water may penetrate between the copper mylar tape 100 and the sheath layer 20 to weaken the durability of the cable when the copper mylar tape 100 and the sheath layer 20 are not fully adhered to each other. In particular, when water flows into an underground tunnel or a protective pipe in which an underground buried high-voltage cable 10 is embedded due to heavy rain or flood, the copper mylar tape 100 of the underground high-voltage cable 10 and the sheath layer 20 There is a possibility that water may be introduced and the high-voltage cable 10 may be blown. The copper mylar tape 100 of the present invention can be completely bonded to the sheath layer 20 without any gaps and the watertightness of the high-voltage cable 10 can be enhanced.

Also, since the outer surface of the copper Mylar tape 100 and the sheath layer 20 are fusion-bonded to each other, the three conductive core wires 10a, 10b, and 10c can be firmly fixed so as not to move.

Although the shielding and grounding portions 18 formed at the outermost portions of the conductor cores 10a, 10b and 10c are shown as being separated from the inner surface of the copper mylar tape 100 for convenience, in FIGS. 2 and 3, They are actually formed in close contact with each other.

When the conductor wires 10a, 10b and 10c are in close contact with each other in the shape of a triangle, since the conductor wires 10a, 10b and 10c are cylindrical (circular in cross section) Lt; / RTI > Therefore, the underground high-voltage cable 10 is connected to the hollow space 62 of the triangular shape formed at the center portion of the conductor core wires 10a, 10b, 10c so as to come in contact with each other in a triangular shape, (The three cores) can be prevented from being shaken by inserting the cores 63 and the braided cores 63 and the braided cores 63 constituting the shielding and grounding portions 18, which will be described later, It is possible to prevent a phenomenon of pushing or tilting to one side).

In addition, void spaces 61 are formed between any two of the conductor wires 10a, 10b and 10c and the copper mylar tapes 100. In this embodiment, however, The respective core wires (i.e., the three cores) are fixed in a triangular shape by the copper mylar tape 100 and the sheath layer 20 so that no flow of each core wire occurs, There is an effect of reducing the weight of the underground high voltage cable 10 having the copper mylar tape 100 according to the present invention.

The copper mylar tape 100 for an underground embedded high voltage cable includes an oxidation preventing layer 110, a first copper layer 120, a base layer 130, a second copper layer 140, a laminate layer 150, , And an adhesive layer (160).

The first copper layer 120 is adhered to the first surface 130a of the base layer 130 by the adhesive layer 160 and the second copper layer 140 is adhered to the second surface 130b of the base layer 130 Can be adhered by the adhesive layer (160). The first copper layer 120, the base layer 130, and the second copper layer 140 may be sequentially stacked.

The first copper layer 120 faces the core portion of the cable and the three conductor cores 10a, 10b and 10c and is in contact with the shielding portion 18 disposed at the outermost portion of the conductor cores 10a, 10b and 10c have. The second copper layer 140 may be directed to the sheath layer 20 of the cable. The first copper layer 120, the second copper layer 140, and the shield 18 may be electrically connected to each other by a ground. The leakage current or the fault current of the cable flows through the first copper layer 120, the second copper foil layer 140, and the shielding portion 18, thereby enhancing the electrical shielding effect of the cable.

The base layer 130 is disposed between the first copper foil layer 120 and the second copper foil layer 140 and bonded to the first copper foil layer 120 and the second copper foil layer 140 by the adhesive layer 160. [ .

The adhesive layer 160 is formed on one surface 130a of the base layer 130 and the opposite surface 130b of the base layer 130 and the first copper layer 120 is adhered to one surface 130a of the base layer 130. [ And the second copper layer 140 may be adhered to the other surface 130b of the base layer 130.

The base layer 130 may be made of polyester.

The base layer 130 may be disposed on the first copper layer 120 and the second copper layer 140 to increase the flexibility of the underground high voltage cable 10.

In detail, since a high voltage of 22.9 KV is applied to the underground high-voltage cable 10, the copper mylar tape 100 is attached to the copper mylar tape 100 together with the shield 18 to prevent electric accidents due to unbalanced currents and leakage currents between the phases. Layer. The copper foil layer of the copper mylar tape 100 must have a predetermined thickness or more for shielding the unbalanced current or the leakage current between each phase. However, when the thickness of the copper foil layer is increased, the elongation is decreased and the flexibility of the high-voltage cable 10 is reduced, which makes the installation process difficult. In other words, the underground high-voltage cable 10 is wound on a reel, moves to a place where it is installed, and is then reeled from the reel. If the flexibility and elongation of the cable are low, It is difficult to straighten them again.

The present invention can ensure the flexibility of the high-voltage cable 10 by placing the base layer 130 between the first copper foil layer 120 and the second copper foil layer 140. The thickness t0 of the base layer 130 is larger than the thicknesses t1 and t2 of the first copper layer 120 and the second copper layer 140 and the thickness t1 of the first copper layer 120 t1) of the first copper layer 140 and the thickness t2 of the second copper layer 140 (t2).

If the thickness t0 of the base layer 130 is thinner than the thicknesses t1 and t2 of the first copper layer 120 and the second copper layer 140 respectively, the flexibility and elongation of the high- If the thickness t0 of the base layer 130 is greater than the sum of the thicknesses t1 and t2 of the first copper layer 120 and the second copper layer 140, the first copper layer 120 and the second copper layer 140, There is a problem that the shielded ground effect for eliminating the unbalanced current between phases and suppressing the generation of leakage current is deteriorated.

The flexibility of the high-voltage cable and the shielding grounding effect can not be achieved at the same time when the base layer and the single-layer copper foil layer are formed. However, in the present invention, the thickness t0 of the base layer 130 is larger than the thicknesses t1 and t2 of the first and second copper layers 120 and 140, 2 copper foil layer 140, the flexibility and shielding effect of the high-voltage cable can be achieved at the same time.

In addition, the underground high-voltage cable (10) may flow through a very large fault current instantaneously in the event of a short circuit due to insulation breakdown, causing the cable to melt or fire. The fault current flows not only through the conductor but also through the ground to the shield 18. Therefore, if the shielding portion 18 does not endure a certain short-circuit capacity (the breakdown current and the breakdown duration that it can sustain), the whole cable will be damaged. Since the underground high-voltage cable 10 is applied with a high voltage, it is difficult to safely shield the fault current with the shielding portion 18 alone.

The first copper layer 120 and the second copper layer 140 having a predetermined thickness can secure a short-circuit capacity together with the shielding portion 18 through the ground to prevent breakage of the high-voltage cable due to a fault current .

The first copper layer 120 adhered to the first surface 130a of the base layer 130 when the first surface 130a of the base layer 130 faces the conductor cores 10a, 10b, and 10c of the high- The antioxidant layer 110 may be formed on one surface 120a of the substrate 120a. The antioxidant layer 110 may be formed on one surface 120a of the first copper layer 120 facing the conductor cores 10a, 10b, and 10c.

In one example, the antioxidant layer 110 comprises 7-12% by weight of cellulose selected from the group consisting of hydroxyalkylcellulose, hydroxymethylcellulose and hydroxyethylcellulose, 4-6% by weight of polyamide, 6% by weight of vinyl resin 6 1 to 3 weight% of acrylic resin, 5 to 9 weight% of urethane resin, 11 to 17 weight% of conductive pigment, 6 to 10 weight% of pigment, 8 to 12 weight% of pearl content, 1 to 3 weight of synthetic mica , 8-12 wt% toluene, 12-18 wt% methyl ethyl ketone, 4-6 wt% ethyl acetate, and 3-5 wt% cyclohexane.

As another example, the antioxidant layer 110 may comprise from 9 to 9.5% by weight of cellulose, from 5 to 5.5% by weight of amide copolymer, from 8 to 8.5% by weight of vinyl resin, from 2 to 2.5% by weight of acrylic resin, 14 to 15 wt% of conductive pigment, 8 to 8.5 wt% of pigment, 10 to 11 wt% of pearl powder, 2 to 2.5 wt% of macanite, 10 to 11 wt% of toluene, 15 to 16 wt% of methyl ethyl ketone, To 5.5 wt%, and cyclohexane (4 to 4.5 wt%).

The antioxidant layer 110 is formed on the insulating coating 15 of the rubber product such as chloroprene rubber CR in the cable (for example, the insulating portion 15, the second electric field relieving portion 16, the third electric field relieving portion 17 ) And the like, gas, oxygen, and sodium chloride (NaCl) can prevent the tape 100 from being damaged.

The oxidation preventing layer 110 can maintain the conductivity at 99.8 to 103%. Accordingly, the anti-oxidation layer 110 is in contact with the shielding portion 18, thereby preventing an induced current generated according to each phase-to-phase unbalanced current (that is, a three-phase unbalanced current flowing through each core wire) from being deflected.

The leakage current or the fault current of the cable flows to the first copper foil layer 120 and the shielding portion 18 due to the high conductivity of the oxidation preventing layer 110 to further enhance the electric shielding effect of the cable.

The laminate layer 150 may be formed on one surface 140a of the second copper layer 140 facing the sheath layer 20 of the high voltage cable 10. [

The laminate layer 150 may be formed of a material that can be welded to the sheath layer 20. The laminate layer 150 is melted and bonded to the second copper foil layer 140 on one side and adhered to the sheath layer 20 on the other side so that water is drawn toward the conductor cores 10a, 10b and 10c inside the laminate layer 150 You can prevent it from penetrating.

As an example, the laminate layer 150 may be made of ethylene acrylic acid (EAA). EAA may be composed of 70% by weight of PE (polyethylene), 20% by weight of a binder and 10% by weight of an acid. EAA may be exposed to an acid in the EAA by heating at a temperature of 60 占 폚 or higher to partially corrode the surface of the second copper layer 140. [ The PE penetrates into the corroded surface and solidifies, so that the laminate layer 150 can be melt-adhered to the second copper foil layer 140. The laminate layer 150 may be bonded to the newly formed sheath layer 20 by melting the outer surface of the laminate layer 150 during the sheath layer forming process.

The sheath layer 20 may be made of a material having water-tightness (property of not penetrating water into the conductor), weather resistance (property corresponding to environmental stress cracking), and flame retardant property (e.g., LLDPE). For example, the sheath layer 20 is extrusion-coated with at least 2 mm thick weather-resistant black LLDPE (Linear Low Density Polyethylene Film). In this case, the color is not necessarily limited to black.

Each of the conductor cores 10a, 10b, and 10c wrapped by the sheath layer 20 may be twisted together in a concentric manner. Accordingly, it is possible to improve the rigidity of the underground high-voltage cable 10 by preventing the conductor wires 10a, 10b, and 10c from being widened (that is, the phenomenon that the core wires expand and fall away from each other).

Each of the conductor cores 10a, 10b and 10c includes a first conductor 11 formed of a single conductor at the center thereof, a conductor 11 surrounding the first conductor 11, A third conductor section 13 for covering the periphery of the second conductor section 12 in a longitudinal direction with a plurality of conductors in close contact with each other and a third conductor section 13 surrounding the periphery of the third conductor section 13 in the longitudinal direction An insulating portion 15 for covering the periphery of the first electric field relieving portion 14 so as to closely contact with each other in the longitudinal direction, a first electric field reducing portion 14 for covering the periphery of the insulating portion 15 in a longitudinal direction A third electric field relieving portion 17 that surrounds the second electric field relieving portion 16 so as to closely adhere to the circumference of the second electric field relieving portion 16 in a longitudinal direction, a second electric field relieving portion 16 that surrounds the third electric field relieving portion 17, And a shielding and grounding portion 18 tightly wrapped in the longitudinal direction.

4 to 7 are cross-sectional views of a copper mylar tape for an underground embedded high voltage cable according to an embodiment of the present invention.

Referring to FIG. 4, the base layer 130 may be joined to the first copper layer 120. The first copper layer 120 may be adhered to the base layer 130 by an adhesive layer 160. An adhesive layer 160 is applied on one side 130a of the base layer 130 and a first copper layer 120 is disposed on the adhesive layer 160 to form a first copper layer 120 and a second copper layer 120. [ The base layer 130 is bonded.

Referring to FIG. 5, a second copper layer 140 may be laminated on the base layer 130 in opposition to the first copper layer 120. The adhesive layer 160 is coated on the other surface 130b of the base layer 130 and the second copper layer 140 is disposed on the adhesive layer 160 to form the second copper layer 120 and the base layer 130 may be bonded. That is, the first copper layer 120 and the second copper layer 140 may be bonded to the base layer 130 with the base layer 130 interposed therebetween.

Referring to FIG. 6, an anti-oxidation layer 110 may be formed on one surface 120a of the first copper layer 120. Referring to FIG. One surface 120a of the first copper layer 120 faces the conductor cores 10a, 10b and 10c of the high voltage cable 10. [ The antioxidant layer 110 may be formed on one surface 120a of the first copper layer 120 facing the conductor cores 10a, 10b, and 10c.

Next, referring to FIG. 7, a laminate layer 150 may be formed on one surface 140a of the second copper foil layer 140. FIG. One surface 140a of the second copper foil layer 140 is a surface facing the sheath layer 20 of the high-voltage cable 10. [ The laminate layer 150 may be formed on one surface 140a of the second copper layer 140 facing the sheath layer 20 of the high voltage cable 10. [

The laminate layer 150 may be formed of a material that can be welded to the sheath layer 20. The laminate layer 150 is melted and bonded to the second copper foil layer 140 on one side and adhered to the sheath layer 20 on the other side so that water is drawn toward the conductor cores 10a, 10b and 10c inside the laminate layer 150 You can prevent it from penetrating.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that various modifications and changes may be made thereto without departing from the scope of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

100: Copper mylar tape for underground embedded high voltage cable
110: oxidation preventing layer
120: first copper layer
130: base layer
140: second copper foil layer
150: Laminate layer

Claims (7)

1. A copper mylar tape for underground embedded high-voltage cable which surrounds the core portion inside the sheath layer in an underground embedded high-voltage cable having a core portion made up of three conductor cores and a sheath layer surrounding the core portion,
A first copper layer adjacent to the core portion;
A second copper layer adjacent to the sheath layer;
A base layer disposed between the first copper layer and the second copper layer and adhered to the first copper layer and the second copper layer by an adhesive layer;
An antioxidant layer formed on one surface of the first copper foil layer facing the core portion; And
A laminate layer formed on one surface of the second copper foil layer facing the sheath layer; And,
The laminate layer is melt-adhered to the second copper foil layer on one side and adhered to the sheath layer on the other side to prevent water from penetrating into the core part inside the laminate layer,
The laminate layer is made of EAA (ethylene acrylic acid) containing 70% by weight of PE, 20% by weight of a binder and 10% by weight of an acid,
The laminate layer is heated to a temperature of 60 占 폚 or higher so that an acid is exposed and melted and bonded to the second copper foil layer,
The laminate layer is partially melted and joined to the sheath layer in the sheath layer forming process,
Wherein the thickness of the base layer is larger than the thickness of the first copper foil layer and the thickness of the second copper foil layer and is smaller than the sum of the thickness of the first copper foil layer and the thickness of the second copper foil layer. Copper mylar tape for cable. delete delete delete delete delete The method according to claim 1,
Wherein the base layer is made of polyester. ≪ RTI ID = 0.0 > 11. < / RTI >

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