WO2018182078A1 - Direct current power cable joining system - Google Patents

Abstract

Provided is a direct current power cable joining system capable of preventing copper powder from leaking out of a cable.

Description

DC power cable intermediate connection system

The present invention relates to a DC power cable intermediate connection system. More particularly, the present invention relates to a DC power cable intermediate connection system capable of preventing copper leakage from power cables.

In general, a power cable is used to supply power to a desired place through the ground, the ground or the sea floor by using a conductor that supplies the power.

The power cable is connected by an intermediate junction box (Joint box) at intervals of several hundred meters or tens of kilometers, and the end of the power cable is connected to the overhead line by a termination connection box. In the case of connecting the power cable in the intermediate junction box or the termination box, the conductor is first connected while the insulation layer of the cable is exposed, and the reinforcement insulation layer is formed by winding the insulation paper impregnated with high viscosity insulation oil on the surface of the insulation layer. . In this case, during the winding of the insulating paper, that is, applying the insulating oil between the insulating papers, the insulating paper is supported, and then the outer semiconducting layer, the metal sheath and / or the anticorrosive layer are restored.

When a pair of cables, for example, insulated oil-impregnated power cables are connected by intermediate connection, as the current flows through the cable, the conductors in the cable heat up, and the viscosity of the insulating oil in the cable decreases, so that the copper content between the conductor wires is gravity Can move in the direction. Copper moving in the direction of gravity flows into the reinforcing insulation layer, there is a problem that the breakdown occurs in the copper flows out of the reinforcing insulation layer.

An object of the present invention is to provide a DC power cable intermediate connection system that can prevent copper from leaking out of the cable.

An intermediate junction box according to an embodiment of the present invention includes a conductor, an inner semiconducting layer, an insulating layer, and an outer semiconducting layer, and connects a pair of cables in which the inner semiconducting layer, the insulating layer, and the outer semiconducting layer are sequentially peeled off. In the intermediate connection, the conductor crimp sleeve for electrically connecting the conductors of the pair of cables; A reinforcement insulating layer having an innermost layer made of kraft paper and an outermost layer made of composite insulating paper, and covering at least a portion of the conductor, the conductor crimp sleeve, and the insulating layer of the power cable; And a copper outflow prevention part disposed between the conductor crimp sleeve and the conductor to prevent the outflow of copper powder that may be generated from the conductor. It may be provided.

In the present invention, the insulating layer of the cable, the inner semiconductive layer, the first insulating layer made of kraft paper impregnated with insulating oil; A second insulating layer surrounding the first insulating layer and made of a composite insulating paper impregnated with insulating oil; And a third insulating layer surrounding the second insulating layer, the third insulating layer comprising kraft paper impregnated with insulating oil, wherein the copper powder leakage preventing part is disposed on the conductor exposed between the first insulating layer and the conductor pressing sleeve. Carbon base layer; And a copper plate disposed between the conductor crimp sleeve and the conductor. It includes, the carbon paper layer may be located between the conductor crimp sleeve and the conductor.

In the present invention, the carbon paper layer may be made by extending the inner semiconducting layer of the cable.

In the present invention, the carbon paper layer may wind a plurality of sheets of carbon paper on the conductor, and may be formed of a gap winding after the voiding.

In the present invention, the copper powder leakage preventing unit may further include a carbon creep paper layer surrounding the carbon paper layer, the copper plate, and the conductor pressing sleeve.

In the present invention, the copper powder leakage preventing unit may further include an insulating paper wound on the carbon creep paper layer.

In the present invention, the conductor crimping sleeve includes a body portion having at least two corrugations formed to protrude from an inner surface and at least one corrugation bone formed between the corrugations, wherein the copper plate is formed at one end of the conductor crimping sleeve. It may be disposed up to the corrugated acid and not exceed the vertex of the corrugated acid.

A method of connecting a pair of cables using an intermediate junction box for a cable according to an embodiment of the present invention includes a conductor, an inner semiconducting layer, an insulating layer, and an outer semiconducting layer, and the inner semiconducting layer, the insulating layer, and the outside. CLAIMS What is claimed is: 1. A method of connecting a pair of cables in which a semiconducting layer is sequentially peeled off using an intermediate junction box for cable, the method comprising: wrapping the conductor with a copper plate including a portion of the inner semiconducting layer exposed; Holding each end of the pair of conductors exposed by the pair of cables with a conductor crimp sleeve to connect the pair of conductors; Surrounding the exposed inner semiconducting layer and the conductor crimp sleeve with a carbon creep paper layer; Winding insulating paper on the carbon creep paper layer; Wrapping at least a portion of the insulating paper and the insulating layer of the cable with a reinforcing insulating layer; It may be provided.

In the present invention, the inner semiconducting layer may be made of a plurality of carbon paper winding on the conductor, and the gap winding after the winding.

In the present invention, the inner semiconducting layer may extend from the cable so that one end thereof extends between the copper plate and the conductor corresponding to the crimp sleeve.

In the present invention, the copper plate may be disposed inside one end of the conductor pressing sleeve without deviating from the position corresponding to the inner circumferential surface of the conductor pressing sleeve.

In the present invention, the conductor pressing sleeve has at least two or more protrusions formed on the outer surface of the conductor before the gripping and at least one concave portion formed between the protrusions on the outer surface, the conductor connecting step, the protrusion Pressing a region in which the recess is formed to form a wrinkle acid projecting into the conductor pressing sleeve to hold the conductor; And smoothing the outer surface of the conductor pressing sleeve. It may include.

In the present invention, the copper plate may be disposed from one end of the conductor crimp sleeve to the corrugated acid, and may not exceed the vertex of the corrugated acid.

In the present invention, the insulating layer of the cable, the inner semiconductive layer, the first insulating layer made of kraft paper impregnated with insulating oil; A second insulating layer surrounding the first insulating layer and made of a composite insulating paper impregnated with insulating oil; And a third insulating layer surrounding the second insulating layer and made of kraft paper impregnated with insulating oil, wherein the step of enclosing the carbon creep paper layer includes: exposing the first insulating layer and the conductor crimp sleeve; Carbon creep paper may be formed in a wrap wound to surround the inner semiconducting layer and the conductor crimp sleeve.

In the present invention, the reinforcing insulating layer, the first reinforcing insulating layer formed on the insulating paper to the outer diameter of the third insulating layer; And a second reinforcing insulating layer formed on the first reinforcing insulating layer. Can be made.

In the present invention, the width of the second reinforcement insulating layer in the longitudinal direction of the first reinforcement insulating layer is narrow in the radial direction can be formed slopes at both ends.

According to the present invention, in the conductor of a pair of cables connected by an intermediate connection, the copper powder leaked out by preventing the copper powder between conductor wires from moving in the gravity direction and outflowing to the reinforcing insulation layer due to the decrease in the viscosity of the insulating oil caused by the conductor heating. It is possible to prevent the dielectric breakdown of the reinforcement insulating layer due to.

1 is a perspective view showing an internal configuration of a power cable.

2 is a partial cutaway view schematically showing a cable connected by an intermediate connection.

3 is an enlarged view of a portion C of FIG. 2.

4 is a cross-sectional view showing a conductor crimp sleeve before crimping.

5 is a cross-sectional view showing a conductor crimp sleeve after crimping.

6 to 10 are cross-sectional views of various embodiments showing the conductor pressing sleeve after the pressing.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. Like numbers refer to like elements throughout.

In general, the oil-impregnated cable is connected by intermediate connection at intervals of several hundred m or several km, and the end of the insulation-impregnated cable is connected to the overhead line by terminating the connection. Hereinafter, the configuration of the insulation oil-impregnated power cable will be described first, and then the connection process of the junction box will be described.

1 is a partially cutaway perspective view illustrating an internal configuration of an ultra high voltage direct current power cable.

Referring to FIG. 1, the power cable 100 includes a conductor 11, an inner semiconducting layer 12, an insulating layer 14, and an outer semiconducting layer 16, along the conductor 11 in the cable length direction. Only the cable core portion 10 which transmits electric power and prevents leakage of current in the cable radial direction is provided.

The conductor 11 serves as a passage through which current flows to transmit power, and has a high conductivity to minimize power loss, and a material having strength and flexibility suitable for cable production and use, for example, copper or aluminum. Can be made.

As shown in FIG. 1, the conductor 11 includes a flat element wire layer 11c including a circular center element line 11a and a flat element line 11b twisted to enclose the circular center element line 11a. It may be a flat conductor having a circular cross section as a whole, and may be a circular compressed conductor compressed in a circular shape by twisting a plurality of circular wires as another example. The flat conductor has an advantage of reducing the outer diameter of the cable due to a relatively high drop ratio compared to the circular compression conductor.

Since the conductor 11 is formed by stranding a plurality of element wires, the surface thereof is not smooth, so that an electric field may be uneven, and corona discharge is likely to occur partially. In addition, when a gap is formed between the surface of the conductor 11 and the insulating layer 14 described later, the insulating performance may be reduced.

In order to solve the above problems, an inner semiconducting layer 12 may be formed outside the conductor 11. The inner semiconducting layer 12 may have semiconductivity by adding conductive particles such as carbon black, carbon nanotubes, carbon nanoplates, and graphite to an insulating material.

The inner semiconducting layer 12 serves to stabilize the insulation performance by preventing a sudden electric field change between the conductor 11 and the insulating layer 14 described later. In addition, by suppressing uneven charge distribution on the conductor surface, the electric field is made uniform and the gap between the conductor 11 and the insulating layer 14 is prevented from forming, thereby also acting to suppress corona discharge and insulation breakdown. .

The insulating layer 14 is provided on the outside of the inner semiconducting layer 12 to electrically insulate the outside from the current flowing along the conductor 11 to prevent leakage.

The insulating layer 14 may be formed of insulating paper impregnated with insulating oil. That is, the insulating layer 14 may be formed by winding insulating paper in multiple layers so as to surround the inner semiconducting layer 12, and then impregnating the insulating layer with the cable core part. As the insulating oil is absorbed into the insulating paper as described above, the insulating property of the insulating layer 14 may be improved.

The insulating oil is filled in the gap between the inside of the insulating paper and the gap formed by winding the insulating paper to improve the insulating property, and to reduce the frictional force between the insulating paper during bending of the cable to improve the bending characteristics of the cable. Although the type of the insulating oil is not particularly limited, the insulating oil should not be oxidized by heat in contact with the copper or aluminum constituting the conductor 11, and the impregnation temperature, for example, 100 ° C., may be used to easily impregnate the insulating paper. Is preferably a medium viscosity insulating oil having a sufficiently low viscosity and having a kinematic viscosity of 10 to 500 centistokes at 60 ° C or a high viscosity insulating oil having a kinematic viscosity of at least 500 centistokes at 60 ° C.

When using a low viscosity insulating oil having a relatively low viscosity, it is necessary to pressurize the insulating oil by using a lubrication facility, etc., in order to keep the insulating paper impregnated with the insulating oil and to prevent voids in the insulating layer due to the flow of the insulating oil. There is. However, in the case of using a medium viscosity or high viscosity insulating oil, since the flow of the insulating oil is small, there is no need for the oil supply equipment for pressurizing the insulation oil, or the number of necessary oil supply equipment can be reduced, thereby extending the cable extension length. For example, the insulating oil may be one or more insulating oils selected from the group consisting of naphthenic insulating oils, polystyrene insulating oils, mineral oils, alkyl benzene or polybutene synthetic oils, heavy alkates, and the like.

The insulating paper may be kraft paper from which the organic electrolyte in the pulp is removed using kraft pulp as a raw material, or a composite insulating paper in which kraft paper is adhered to one or both surfaces of a plastic film. The plastic film has a higher resistivity than kraft paper adhered to one or both sides thereof, so that even if bubbles are generated in kraft paper according to the flow of insulating oil during an impregnation process or a cable operation, the voltage applied to the bubbles can be alleviated, and polyethylene (Polyethylen) ), Polypropylene resins such as polypropylene, polybutylene, tetrafluoroethylene-hexaxafluoropropylene copolymer, ethylene-tetrafluoroethylene air It may be made of a fluororesin such as coalescing, and preferably made of a polypropylene homopolymer resin having excellent heat resistance.

Specifically, the insulating layer 14 may be formed by winding only kraft and impregnating the insulating oil. In this case, the insulating oil flows in the cable load direction, and voids may occur. On the other hand, in the case of winding the composite insulating paper and impregnating the insulating oil to form the insulating layer 14, the thermoplastic resin such as the polypropylene resin is not impregnated with the insulating oil, the impregnation temperature at the time of cable manufacture or operation at the time of cable operation Thermal expansion occurs depending on the temperature. When the thermoplastic resin is thermally expanded, the surface pressure is applied to the kraft paper stacked thereon to narrow the passage of the insulating oil, so that the flow of the insulating oil may be suppressed in the contraction / expansion of the insulating oil due to gravity or the temperature of the insulating oil. In addition, the composite insulating paper has a higher insulation strength than kraft paper has the advantage of reducing the cable outer diameter.

On the other hand, when the power cable is energized, heat is generated in the conductor that acts as a passage through which the current flows, and the temperature gradually decreases from the inner side to the outer side in the radial direction of the cable so that a temperature difference occurs in the insulating layer 14. do. Therefore, the insulating oil of the insulating layer belonging to the upper section of the conductor, that is, the insulating layer formed on the inner semiconducting layer 12 has a low viscosity and undergoes thermal expansion, and moves outwards. As the viscosity increases and does not return to the original state, voids may occur in the portion of the insulating layer in the section immediately above the conductor.

In addition, a high electric field is applied to the insulating layer formed in the direction of the outer semiconducting layer 16, that is, the insulating layer belonging to the section immediately below the metal sheath, in which the electric field is gradually reversed in response to the temperature difference. The upper section of the conductor and the lower section of the metal sheath may have a high possibility of voids, and may act as a weak part of insulation, which is a starting point of partial discharge, insulation breakdown, etc., as a region in which a high electric field acts according to a temperature change inside the cable.

In order to solve the above-described problem, only kraft may be used as insulating paper in the region including the weak insulation of the insulating layer 14. That is, the insulating layer 14 is divided into a first insulating layer, a second insulating layer, and a third insulating layer in the direction of the outer semiconducting layer 16 which will be described later from the inner semiconducting layer 12. Alternatively, only kraft may be used for the third insulating layer, and the composite insulating paper may be used for the second insulating layer.

In this case, a resistivity difference occurs between the second insulating layer on which the composite insulating paper is wound and the first insulating layer and / or the third insulating layer on which the kraft paper is wound, and the low-resistance of the insulating layer 14 on which the kraft paper is wound The first insulating layer and / or the third insulating layer has a relatively low resistivity, and serves to alleviate an electric field shared in the weak insulation portion. Specifically, a high electric field acts on the second insulating layer on which the composite insulating paper having high resistivity is wound due to the resistive electric field distribution characteristic of the DC cable in which the electric field is distributed according to the resistivity, and the first insulating layer and / or the third insulating layer Since a relatively low electric field acts on the directly included section of the conductor and / or the section immediately below the metal sheath, the electric field acting on the weak insulation part can be alleviated to stabilize the insulation performance.

In addition, the insulating layer 14 may form a third insulating layer thicker than the first insulating layer. The metal sheath 22, which will be described later, is formed on the outside of the insulating layer 14, or when the cable core part is connected to two power cables sequentially exposed from the inside, and then the metal sheath 22 is restored. Since heat may be applied to the second insulating layer of the insulating layer 14 to cause deformation of the plastic film, a second insulating layer is formed thicker than the first insulating layer so that the plastic film of the second insulating layer is removed from the heat. It is desirable to protect. In this case, the thickness of the first insulating layer may be selected in consideration of the impulse surge voltage required for the power cable.

An external semiconducting layer 16 may be provided outside the insulating layer 14. The outer semiconducting layer 16 is formed of a material having semiconductivity by adding conductive particles, such as carbon black, carbon nanotubes, carbon nanoplates, graphite, etc., to an insulating material like the inner semiconducting layer. Non-uniform charge distribution between (14) and the metal sheath 22 described later is suppressed to stabilize the insulation performance. In addition, the outer semiconducting layer 16 smoothes the surface of the insulating layer 14 in the cable to alleviate electric field concentration, thereby preventing corona discharge, and also physically protects the insulating layer 14. Can be. In addition, the outer semiconducting layer 16 may further include a metallized paper. The metallized paper may be formed by laminating an aluminum thin film on kraft paper, and a plurality of perforations may exist to facilitate the impregnation of the insulating layer 14.

The cable core part 10 may further include a moisture absorbing part 21 for preventing moisture from penetrating into the cable. The moisture absorbing portion may be formed between the stranded wires of the conductor 11 and / or outside of the conductor 11, and has a high speed of absorbing moisture penetrating into the cable and excellent ability to maintain the absorption state. It is configured in the form of powder, tape, coating layer or film including a super absorbent polymer (SAP), and serves to prevent moisture from penetrating in the longitudinal direction of the cable. In addition, the moisture absorbing portion may have a semiconductivity to prevent a sudden electric field change.

The cable protection part 20 is provided outside the cable core part 10, and the power cable laid on the sea floor may further include a cable outer part 30. The cable protector and the cable sheath protect the core from various environmental factors such as moisture penetration, mechanical trauma, and corrosion, which can affect the power transmission performance of the cable.

The cable protection unit 20 includes a metal sheath 22 and a polymer sheath 24 to protect the cable from accidental current, external force or other external environmental factors.

The metal sheath 22 may be formed to surround the core part 10. In particular, when the power cable is installed in an environment such as the seabed, it may be formed to seal the cable core portion 10 in order to prevent foreign substances such as moisture from entering the cable core portion 10, The molten metal is extruded to the outside of the cable core 10 so as to have a seamless outer surface so that the ordering performance can be excellent. Lead or aluminum is used as the metal, and in the case of a power cable installed on the sea floor, it is preferable to use lead having excellent corrosion resistance to seawater, and alloy lead containing a metal element to supplement mechanical properties. It is even more preferable to use lead alloys. In addition, the metal sheath 22 is grounded at the end of the power cable and serves as a passage through which an accident current flows in case of an accident such as a ground fault or a short circuit, and protects the cable from external shocks and prevents the electric field from being discharged to the outside of the cable. Can be.

In addition, the metal sheath 22 may be coated with an anti-corrosion compound, for example, blown asphalt, etc. on the surface to further improve the corrosion resistance, water resistance, and the like of the cable and to improve adhesion to the polymer sheath 24. Can be.

In addition, the copper sheath tape or the moisture absorbing layer 21 may be additionally provided between the metal sheath 22 and the cable core 10. The copper wire direct tape consists of a copper wire and a nonwoven tape to facilitate electrical contact between the outer semiconducting layer 16 and the metal sheath 22, and the moisture absorbing layer absorbs moisture that has penetrated the cable. It is formed in the form of powder, tape, coating layer or film including super absorbent polymer (SAP) which has a high speed and excellent ability to maintain an absorbent state. Play a role. In addition, the copper wire direct tape and the water absorbing layer preferably has a semi-conductivity in order to prevent a sudden electric field change, it may be configured to include a copper wire in the water absorbing layer so that both conduction and water absorption.

The polymer sheath 24 is formed on the outside of the metal sheath 22 to improve the corrosion resistance, degree of ordering, etc. of the cable, and to protect the cable from mechanical trauma and other external environmental factors such as heat and ultraviolet rays. Can be. The polymer sheath 24 may be formed of a resin such as polyvinyl chloride (PVC), polyethylene, or the like, and in the case of a power cable installed on the sea floor, it is preferable to use a polyethylene resin having excellent water repellency, and flame retardancy is required. It is preferable to use polyvinyl chloride resin in an environment.

The power cable 100 includes a metal reinforcing layer 26 made of a galvanized steel cape or the like inside or outside the polymer sheath, and the metal sheath 22 is expanded by the expansion of the insulating oil. It can prevent. In addition, the upper and / or lower portion of the metal reinforcing layer 26 may be provided with a bedding layer (not shown) made of a semi-conductive nonwoven tape or the like to buffer the external force applied to the power cable, polyvinyl chloride to polyethylene, etc. The outer sheath 28 made of resin can be further provided to further improve the corrosion resistance, water resistance, etc. of the power cable, and further protect the cable from mechanical trauma and other external environmental factors such as heat and ultraviolet rays.

In addition, the power cable installed on the seabed is easy to be traumatized by the anchor of the ship, and may be damaged by bending force caused by currents or waves, friction with the sea bottom, etc. 30 may be further provided.

The cable sheath may include an armor layer 34 and a serving layer 38. The armor layer 34 may be made of steel, galvanized steel, copper, brass, bronze, and the like, and may be configured by at least one layer by cross winding a wire having a circular cross section or the like, and the mechanical characteristics of the power cable It not only functions to enhance performance, but also protects cables from external forces.

The serving layer 38 formed of polypropylene yarn or the like is formed in one or more layers on the upper and / or lower portion of the armor layer 34 to protect the cable, and the serving layer 34 formed on the outermost part is colored. It is composed of two or more different materials to ensure visibility of cables laid on the sea floor.

FIG. 2 is a partial cutaway view schematically showing a cable connected by an intermediate connection. In detail, the insulating oil-impregnated cables 100A and 100B having the configuration as shown in FIG. 1 are connected to each other by the intermediate junction box 200. It is a partial cutaway view schematically showing. 3 is an enlarged view of a portion C of FIG. 2.

2 and 3, first, the conductor of the insulating oil impregnated cables 100A and 100B in a state in which the insulating layers 14A and 14B and the conductors 11A and 11B are exposed in the pair of insulating oil impregnated cables 100A and 100B. Each end of 11A, 11B can be electrically connected. The electrically connected conductors 11A and 11B serve as passages of current, through which power can be transferred. The conductors 11A and 11B are electrically connected to each other by crimping or welding with the conductor crimp sleeve 1P.

As described above, the cable insulation layer 14A may include the first cable insulation layer 14A1, the second cable insulation layer 14A2, and the third cable insulation layer 14A3. The cable insulation layer 14A can be penciled to have a multi-stage structure. As an example, as shown in FIGS. 2 and 6, the cable insulation layer 14A may have a multistage structure of a first fencing stage 14a1, a second fencing stage 14a2, and a third fencing stage 14a3. It can be penciled. The first penciling end 14a1 is composed of an inner semiconducting layer 12, a first cable insulating layer 14A1, and a part of the second cable insulating layer 14A2, and the second penciling end 14a2 is a second cable. The insulating layer 14A2 may be formed, and the third penciling end 14a3 may include a portion of the second cable insulating layer 14A2 and the third cable insulating layer 14A3. This will be described later together with the reinforcement insulating layer.

Between the conductor crimp sleeve 1P and the conductors 11A and 11B, a copper powder leakage preventing part PC may be disposed to prevent the copper powder from the conductors 11A and 11B from flowing out.

When a pair of cables, for example, an oil-impregnated cable is connected by an intermediate connection, as the current flows through the cable, the conductors in the cable heat up, and the viscosity of the insulating oil in the cable decreases, so that the copper content between the conductor wires is in the direction of gravity Can be moved. Copper moving in the direction of gravity flows into the reinforcing insulation layer, there is a problem that the breakdown occurs in the copper flows out of the reinforcing insulation layer.

According to one embodiment of the present invention, the copper powder leakage preventing part (PC) is between the conductor crimp sleeve (1P) and the conductor (11A, 11B), and / or the innermost layer (2101A) of the first reinforcing insulating layer (2101) and By being disposed between the conductors 11A and 11B, it is possible to prevent the copper generated in the conductors 11A and 11B from leaking into the reinforcing insulating layer 210.

The copper powder leakage preventing part PC is, for example, a first electric field uniformization layer 12 positioned on the conductor 11A exposed between the first penciling end 14a1 of the cable 100A and the conductor crimp sleeve 1P. ), And a copper powder leakage preventing plate 211 disposed between the conductor pressing sleeve 1P and the conductor 11A.

The first electric field uniformization layer 12 may be disposed between the conductor crimp sleeve and the conductor, and between the reinforcement insulating layer and the conductor. That is, the first electric field uniformization layer 12 may extend not only between the first cable insulation layer 14A1 and the conductor crimp sleeve 1P but also extend between the conductor crimp sleeve 1P and the conductor 11A.

For example, the first electric field homogenization layer 12 may be formed by extending the inner semiconducting layer of the cable 100A. That is, the first electric field homogenization layer 12 is formed by removing the inner semiconducting layer itself as the inner semiconducting layer itself with the first cable insulation layer 14A1 and leaving a predetermined length. After this removal, the conductor 11A is exposed.

The first field homogenization layer 12 may be formed by winding at least one insulating sheet on the conductor 11A, but the first two sheets may be formed as a void and then as a gap winding.

In detail, the first electric field uniformization layer 12 has a plurality of semiconducting properties so as to overlap the innermost layer adjacent to the conductors 11A and 11B of the DC power cables 100A and 100B in the air, that is, in the longitudinal direction of the cable. It is formed by winding the tape, and after the winding, it can be made by the gap winding, that is, by winding the semiconducting tape which is a kind of insulating paper so as to be spaced apart in the longitudinal direction of the DC power cables 100A, 100B.

As another example, the first electric field uniformization layer 12 wraps the innermost layer adjacent to the conductors of the DC power cables 100A and 100B, that is, on the conductors 11A and 11B of the DC power cables 100A and 100B. A sheet of carbon paper, which is a kind of insulating paper, is superposed on one side of the DC power cables 100A and 100B to form a transverse winding in the longitudinal direction of the DC power cables. It is formed by the air space, and can be made by the side winding so that the gap winding, that is, a semi-conducting tape (carbon paper), which is a kind of insulating paper, is spaced apart in the longitudinal direction of the DC power cables 100A and 100B.

Since the first electric field uniformization layer 12 is formed as a gap winding after the voiding space, it is possible to minimize the leakage of copper powder by minimizing the voids of the plurality of insulating papers (carbon paper). In addition, since a plurality of insulating papers (carbon papers) are blanked and then supported by a gap winding, bending characteristics can be improved.

The first electric field homogenization layer 12 may be extended between the conductor crimp sleeve 1P and the conductor 11A by exposing the inner semiconducting layer of the exposed cable 100A by removing the first cable insulation layer 14A1. . That is, one end of the first electric field uniformization layer 12 may be located between the conductor crimp sleeve 1P and the conductor 11A.

The first electric field homogenization layer 12 is, for example, a position at which a crimp (1Pa 'in FIG. 5) of the inner surface of the conductor crimp sleeve 1P formed by crimping the conductor crimp sleeve 1P starts, that is, conductor crimping. It may extend to one end of the sleeve 1P. As another example, as shown in FIG. 5, the first field homogenization layer 12 may extend to just before the highest ridge T in the corrugated acid (1Pa ′ in FIG. 5). This extension ensures a sufficient current path between the conductor 11A of the cable and the conductor crimp sleeve 1Pa. As another example, as shown in FIG. 6, the first field homogenization layer 12 may extend beyond the highest ridge T in the corrugated acid (1Pa ′ in FIG. 5). This will be described later.

The copper powder leakage preventing plate 211 may be disposed between the conductor crimp sleeve 1P and the conductor 11A. That is, the copper powder leakage preventing plate 211 may be disposed to correspond to the inside of the conductor compression sleeve 1P and may not exceed the conductor compression sleeve 1P. As another example, as shown in FIGS. 9 and 10, the copper flux leakage preventing plate 211 ″ may extend beyond both ends of the conductor compression sleeve 1P as well as between the conductor compression sleeve 1P and the conductor 11A. .

The copper powder leakage preventing plate 211 may be formed of a material having a structure that is dense so that copper powder may not penetrate, and preferably, may be formed of a metal material capable of withstanding the force acting when the compression sleeve is pressed. The copper powder leakage preventing plate 211 may be made of copper, aluminum, a copper alloy, or an aluminum alloy to correspond to the material of the conductors 11A and 11B of the cables 100A and 100B.

The copper powder leakage preventing plate 211 may be formed by, for example, wrapping a portion of the first electric field homogenization layer 12 and the conductor 11A with copper tape and ending or soldering the end portions of the copper tape which are in contact with each other. When both ends of the copper tape are soldered to form the copper leakage prevention plate 211, it is preferable to smoothly process the connection part of the solder so that no edge is generated.

In this way, the copper leakage prevention plate 211 is formed between the conductor pressing sleeve 1P and the conductor 11A so as to surround the cable conductor 11A by the end, so that the outflow path of the copper generated in the conductor 11A is minimized. As a result, the copper powder may be blocked by the copper powder leakage preventing plate 211.

One end of the copper powder leakage preventing plate 211 facing the end of the cable conductor 11A is over the corrugated peak 1Pa 'formed on its inner side by crimping the conductor crimp sleeve 1P to the corrugated bone 1Pb'. Starting from the adjacent position a1 and extending toward the first cable insulation layer 14A1, the pressing force to the conductor crimp sleeve 1P can be applied. As an example, as shown in FIG. 5, the copper flow-out prevention plate 211 preferably extends beyond the ridgeline T, which is the highest point in the corrugated mountain 1Pa '.

In addition, the other end a2 of the copper powder leakage preventing plate 211 toward the first cable insulation layer 14A1 of the cable may protrude from the conductor crimp sleeve 1P and may not act as an edge.

Referring to FIGS. 4 and 5, the arrangement of the first electric field homogenization layer 12 and the copper powder leakage preventing plate 211 will be described below.

4 and 5 are cross-sectional views showing a state in which a pair of conductors 11A and 11B are electrically connected to each other by a conductor crimp sleeve. 4 is a cross-sectional view showing a conductor crimp sleeve before the crimping, and FIG. 5 is a cross-sectional view showing a conductor crimp sleeve after the crimping.

Referring to FIG. 4, when electrically connecting the pair of conductors 11A and 11B, each end of the pair of conductors 11A and 11B is fitted to the conductor receiving portion of the conductor crimp sleeve 1P. As shown in FIG. 5, the outer surface of the conductor pressing sleeve is crimped by a crimping device to firmly support the connection state by holding the pair of conductors, and after pressing, the outer surface of the conductor pressing sleeve is smoothly trimmed to obtain a flat surface. Is formed.

Specifically, the conductor crimp sleeve 1P has at least two protrusions 1Pa protruding from the outer surface and at least one recess 1Pb formed between the protrusions 1Pa, as shown in FIG. 5. And a region in which the protrusion 1Pa is formed as shown in FIG. 5 is compressed by the pressing device to protrude to the inside of the conductor pressing sleeve 1P to form a wrinkled peak 1Pa '. As a result, the end of each conductor is gripped, and the outer surface of the conductor pressing sleeve 1P which is uneven by pressing can be smoothed to prevent electric field concentration, corona discharge, etc. of the outer surface of the conductor pressing sleeve.

As described above, the first electric field homogenization layer 12 extends in the direction from the inner semiconducting layer of the cable 100A toward the conductor crimp sleeve 1P so that one end thereof is between the conductor crimp sleeve 1P and the conductor 11A. The copper powder leakage preventing plate 211 has one end portion facing the end of the conductor 11A and the other end portion facing the first cable insulation layer 14A1 of the cable 100A does not protrude from the conductor crimp sleeve 1P. It can extend to the length of.

By crimping the conductor crimp sleeve 1P, a wrinkle acid 1Pa 'is formed on the inner surface of the conductor crimp sleeve 1P, and the first electric field uniformization layer 12 is formed of the crimp acid ( 5, 1Pa ') extends to just before the highest ridge T, and the copper flow prevention plate 211 extends beyond the ridge T which is the highest point of the corrugated mountain 1Pa'. Can be.

6 to 10 are views showing various modifications of the first electric field homogenization layer and the copper powder leakage preventing plate.

Referring to FIG. 6, the first electric field uniformization layer 121 extends from the inner semiconducting layer of the cable 100A toward the conductor crimp sleeve 1P so that one end thereof is the conductor crimp sleeve 1P and the conductor 11A. Disposed between the two parts, the one end portion of the copper leakage preventing plate 211 facing the first cable insulation layer 14A1 of the cable 100A does not protrude from the conductor crimp sleeve 1P and faces the end of the conductor 11A. The portion may extend to a predetermined length.

By crimping the conductor crimping sleeve 1P, a wrinkle acid 1Pa 'is formed on the inner surface of the conductor crimping sleeve 1P, and the first electric field uniformizing layer 121 is formed of the corrugated acid ( In FIG. 6Pa '), it extends beyond the highest ridge T, and the copper flow-out prevention plate 211 may extend beyond the ridge T which is the highest point in the corrugated acid 1Pa'.

Referring to FIG. 7, the first electric field uniformization layer 122 extends from the inner semiconducting layer of the cable 100A toward the conductor pressing sleeve 1P so that one end thereof is the conductor pressing sleeve 1P and the conductor 11A. It is disposed between, and the copper powder outflow prevention plate 211 'may be disposed over the entire surface between the conductor pressing sleeve (1P) and the conductor (11A). In other words, in Figs. 5 and 6, one copper leakage preventing plate 211 is disposed between the conductor 11A and the conductor pressing sleeve 1P, and another one between the conductor 11B and the conductor pressing sleeve 1P. The copper powder leakage preventing plate 211 is arranged, but in the embodiment shown in FIG. 7, one copper powder leakage preventing plate 211 'is disposed between the conductor crimp sleeve 1P and the conductors 11A and 11B. The copper leakage preventing plate 211 'has both ends, that is, an end facing the first cable insulation layer 14A1 of the cable 100A and an end facing the first cable insulation layer 14B1 of the cable 100A. It may be disposed between the conductor crimp sleeve 1P and the conductors 11A and 11B without protruding from the sleeve 1P.

By crimping the conductor crimp sleeve 1P, a wrinkle acid 1Pa 'is formed on the inner surface of the conductor crimp sleeve 1P, and the first electric field homogenization layer 122 is formed of the crimp acid ( It may extend beyond the highest ridge T in 1Pa 'of FIG. 7.

Referring to FIG. 8, the first electric field uniformization layer 123 extends from the inner semiconducting layer of the cable 100A toward the conductor crimp sleeve 1P so that one end thereof is the conductor crimp sleeve 1P and the conductor 11A. It is disposed between, and the copper powder outflow prevention plate 211 'may be disposed over the entire surface between the conductor pressing sleeve (1P) and the conductor (11A). In other words, in Figs. 5 and 6, one copper leakage preventing plate 211 is disposed between the conductor 11A and the conductor pressing sleeve 1P, and another one between the conductor 11B and the conductor pressing sleeve 1P. Although the copper powder leakage preventing plate 211 is disposed, in the embodiment shown in FIG. 8, one copper powder leakage preventing plate 211 'is disposed between the conductor crimp sleeve 1P and the conductors 11A and 11B. The copper leakage preventing plate 211 'has both ends, that is, an end facing the first cable insulation layer 14A1 of the cable 100A and an end facing the first cable insulation layer 14B1 of the cable 100A. It may be disposed between the conductor crimp sleeve 1P and the conductors 11A and 11B without protruding from the sleeve 1P.

By crimping the conductor crimp sleeve 1P, a wrinkle acid 1Pa 'is formed on the inner surface of the conductor crimp sleeve 1P, and the first electric field homogenization layer 123 is formed of the crimp acid ( In 1Pa 'of FIG. 8, it may extend to just before the highest ridge T.

Referring to FIG. 9, the first electric field uniformization layer 124 extends from the inner semiconducting layer of the cable 100A toward the conductor pressing sleeve 1P so that one end thereof is the conductor pressing sleeve 1P and the conductor 11A. Disposed between, the other end portion of the copper leakage preventing plate 211 ", which faces the first cable insulation layer 14A1 of the cable 100A, protrudes from the conductor crimp sleeve 1P and extends to the end of the conductor 11A. The one end facing toward the side may extend to a predetermined length. That is, a portion of the copper flux leakage preventing plate 211 " is disposed between the conductor crimp sleeve 1P and the conductors 11A and 11B and the other portion of the conductor crimp sleeve ( It may extend beyond 1P) toward the cable insulation layer 14A.

By crimping the conductor crimp sleeve 1P, a wrinkle acid 1Pa 'is formed on the inner surface of the conductor crimp sleeve 1P, and the first electric field uniformization layer 124 is formed of the crimp acid ( In FIG. 6Pa '), it extends beyond the highest ridge T, and the copper flow-out prevention plate 211 may extend beyond the ridge T which is the highest point in the corrugated acid 1Pa'. In the region beyond the conductor crimp sleeve 1P, another portion of the copper leakage preventing plate 211 ″ and the first electric field homogenization layer 124 may overlap each other.

Referring to FIG. 10, the first electric field uniformization layer 125 extends from the inner semiconducting layer of the cable 100A toward the conductor crimp sleeve 1P so that one end thereof is the conductor crimp sleeve 1P and the conductor 11A. Disposed between, the other end portion of the copper leakage preventing plate 211 ", which faces the first cable insulation layer 14A1 of the cable 100A, protrudes from the conductor crimp sleeve 1P and extends to the end of the conductor 11A. The one end facing toward the side may extend to a predetermined length. That is, a portion of the copper flux leakage preventing plate 211 " is disposed between the conductor crimp sleeve 1P and the conductors 11A and 11B and the other portion of the conductor crimp sleeve ( It may extend beyond 1P) toward the cable insulation layer 14A.

By crimping the conductor crimping sleeve 1P, a wrinkle acid 1Pa 'is formed on the inner surface of the conductor crimping sleeve 1P, and the first electric field uniformizing layer 124 is formed of the corrugated acid ( In FIG. 10, the maximum ridge (T) falls short of the highest ridge T, and the copper flow-out prevention plate 211 extends beyond the ridge (T), which is the highest point in the corrugated mountain 1Pa '. Can be. In addition, in the region beyond the conductor pressing sleeve 1P, the other portion of the copper flux leakage preventing plate 211 ″ and the first electric field uniformization layer 125 may overlap each other.

Referring to FIG. 3, the copper outflow prevention part PC may include a second field homogenization layer surrounding the first field uniformization layer 12, the copper outflow prevention plate 211, and the conductor compression sleeve 1P. 212 and a pressure layer 213 wound on the second electric field homogenization layer 212 may be further included.

The second electric field homogenization layer 212 wraps a carbon crepe to surround the first electric field homogenization layer 12, the copper powder leakage preventing plate 211, and the conductor crimp sleeve 1P so as to surround the first electric field homogenization layer 212. By strongly adhering the layer 12, the copper powder outflow prevention plate 211, and the conductor crimp sleeve 1P, it is possible to further prevent the copper outflow. That is, it is difficult to maintain the high degree of smoothness after pressing the conductor crimp sleeve 1P and finishing the surface. The second electric field homogenization layer 212 can uniform the surface by wrapping the outer circumferential surface of the polished conductor crimp sleeve 1P to make the electric field at the outer circumferential surface of the conductor crimp sleeve 1P uniform.

In addition, the second field uniform layer 212 may press the first field uniform layer 212 and the copper powder leakage preventing plate 211.

As an example, the second electric field uniformization layer 212 may support carbon creep paper as a wrap winding. That is, the second electric field uniformization layer 212 may be formed by supporting carbon creep paper so as to overlap in the longitudinal direction of the cable.

The second field homogenization layer 212 may be made of carbon paper as another example. The second electric field homogenization layer 212 is preferably made of corrugated carbon paper when considering the step at both ends of the conductor crimp sleeve 1P.

Since the second electric field uniformization layer 212 is semiconductive, it is possible to prevent a sudden electric field change between the conductor crimp sleeve 1P and the reinforcement insulating layer 210.

The pressure layer 213 may be wound on the second field uniform layer 212. The pressurized layer 213 can be more reliably prevented from leaking copper powder by bringing the first electric field uniformizing layer 12, the copper outflow preventing plate 211, the conductor crimp sleeve 1P, and the second electric field uniformizing layer 212 into close contact with each other. Can be.

The pressing layer 213 is preferably supported on the second field homogenization layer 212 in a gap winding in consideration of bending characteristics. That is, the pressure layer 213 may be formed by transverse winding so that the crafttage overlaps in the longitudinal direction of the cable as an example.

The pressure layer 213 may be wound with insulating paper to relieve the electric field on the conductor crimp sleeve 1P, which takes a high electric field when the cable is energized.

The pressing layer 213 may have a volume resistance of 10 ² or more lower than that of the reinforcing insulating layer 2110.

Each conductor of the insulating oil-impregnated cables 100A and 100B is crimped and connected with a conductor crimp sleeve 1P to form a copper powder leakage preventing part PC, and then a cable including a connection portion of the conductors 11A and 11B. A reinforcement insulating layer 210 is formed to surround at least a portion of the insulating layers 14A1, 14A2, and 14A3.

The reinforcement insulating layer 210 may include first reinforcement insulating layers 210A and 210B and second reinforcement insulating layers 210C and 210D. The first reinforcement insulating layers 210A and 210B are formed up to the outer diameter of the third cable insulation layer 14A3 of the cable 100A, and the second reinforcement insulating layers 210C and 210D are the first reinforcement insulating layers 210A and 210B. It can be formed on. That is, the second reinforcement insulating layers 210C and 210D may be stacked in the radial direction of the first reinforcement insulating layers 210A and 210B.

The reinforcing insulating layer 210 may be made of insulating paper and / or composite insulating paper, the innermost layer 210A of the reinforcing insulating layer 210 may be made of insulating paper, and the outermost layer 210D may be made of composite insulating paper.

Hereinafter, look at in detail. In one embodiment, as shown in FIG. 2, a predetermined space remains between the conductor crimp sleeve 1P and the first insulating layer 14A1 located at the innermost side of the insulating layer 14A of the cable 100. can do. The space remaining between the crimp sleeve 1P and the first insulating layer 14A1 located at the innermost side of the insulating layer 14 of the cable 100 is filled with insulating paper such as kraft paper.

In this case, an outer surface of the innermost layer 210A made of insulating paper of the reinforcing insulating layer 210 may be formed from an outer surface of the first insulating layer 14A1 located at the innermost side of the insulating layer 14 of the cable 100. The cable is positioned at approximately the same distance from the longitudinal center axis of the cable.

In addition, the outer surface of the compression sleeve (1P) may be surrounded by a semi-conductive tape in order to uniform the electric field distribution. At this time, when the outer surface of the semiconducting tape is located closer to the longitudinal axis of the cable than the outer surface of the first insulating layer 14A1 located on the innermost side of the insulating layer 14 of the cable, the reinforcing insulating layer An outer surface of the innermost layer 210A of 210 may be formed at approximately the same distance from the longitudinal central axis of the cable.

If the outer surface of the innermost layer 210A made of the insulating paper of the reinforcement insulating layer 210 and the first insulating layer 14A1 located at the innermost side of the insulating layer 14 of the cable is the central axis in the longitudinal direction of the cable, If a step is generated because it is not located at about the same distance from the part, the step where the step occurs acts as an electric field weakness and the electric field is concentrated to cause breakdown.

Meanwhile, the outermost layer 210D of the reinforcing insulating layer 210 is formed above the outer diameter of the exposed insulating layer 14 of the cable 100. Since the exposed conductor 210 of the cable is connected by the crimping sleeve 1P, not only the height of the conductor section is increased by the thickness of the crimping sleeve 1P but also a lot of heat is generated when the cable is energized. In addition, since the insulation reinforcement layer 310 is formed by winding a plurality of insulation papers or composite insulation paper and is relatively weak to insulation, the outermost layer 210D of the insulation reinforcement layer 310 may be formed at or above the outer diameter of the cable insulation layer 14. It is necessary to reinforce the insulation performance by forming.

The outermost layer 210D of the insulating reinforcing layer 310 is composed of a composite insulating paper having an excellent insulating strength compared to the insulating paper. In this case, the operation of the cable 100 to the region 210A to 210C located inside the insulation layer 14 of the cable 100 and the outermost layer of the reinforcing insulation layer 210 having a relatively high temperature. The concentrated electric field may be dispersed in the outermost layer 210D of the reinforcing insulating layer 210.

Meanwhile, intermediate layers 210B and 210C formed of a composite insulating paper layer may be provided between the innermost layer 210A and the outermost layer 210D of the reinforcing insulating layer 210. In this case, the intermediate layer of the reinforcing insulating layer 210 may include a first intermediate layer 210B and a second intermediate layer 210C sequentially from the inner side to the outer side between the innermost layer 210A and the outermost layer 210D. .

In this embodiment, only the innermost layer 210A of the reinforcing insulating layer 210 is made of insulating paper, and the first intermediate layer 210B, the second intermediate layer 210C, and the outermost layer 210D of the reinforcing insulating layer 210 are formed. All may be made of composite insulating paper.

That is, when the innermost layer 210A of the reinforcement insulating layer 210 is formed of an insulating paper layer, and the first intermediate layer 210B and the second intermediate layer 210C are composed of a composite insulating paper, an electric field is distributed according to resistivity. According to the resistive electric field distribution characteristic of the DC cable, a lot of electric fields are distributed in the first intermediate layer 210B and the second intermediate layer 210C formed of a composite insulating paper having a relatively higher resistivity than the kraft paper of the innermost reinforcing layer 210A. . Therefore, the cable becomes relatively high temperature and shrinks / expands the insulating oil relatively actively, and thus bubbles are likely to occur, and the electric field distributed to the innermost layer 210A of the insulating reinforcing layer, which is relatively vulnerable to insulation due to the large electric field strength, is alleviated. Since it is possible to stabilize the insulation performance.

In addition, since all the remaining regions 210B to 210D except for the innermost layer 210A of the reinforcing insulating layer 210 are supported by the composite insulating paper, the work efficiency can be improved to significantly improve productivity and further reduce the defective rate. .

Meanwhile, in another embodiment, the reinforcing insulating layer 210 may include a first intermediate layer 210B made of composite insulating paper and a second intermediate layer 210C made of insulating paper.

At this time, the first intermediate layer 210B and the second intermediate layer 210C provided between the innermost layer 210A and the outermost layer 210D of the reinforcing insulating layer 210 are respectively formed of the cables 100A and 100B. The second cable insulating layer 14A2 of the insulating layers 14A and 14B and the outer third cable insulating layer 14A3 are disposed at the same distance from the center of the cable 100A. As a result, according to the configuration of the other embodiment, the reinforcement insulating layer 210 is less than the outer diameter of the exposed insulating layer 14A of the cable 100A and the same material as the insulating layer 14A of the cable 100A and / or Or it can be said to have a configuration.

In this case, since the innermost layer 210A of the reinforcement insulating layer 210 is made of an insulating paper layer, and the first intermediate layer 210B is made of a composite insulating paper, a resistive electric field distribution of a DC cable in which electric fields are distributed according to resistivity The electric field is distributed in the first intermediate layer 210B formed of a composite insulating paper having a relatively higher resistivity than the kraft paper of the innermost layer 210A of the reinforcing insulating layer 210, depending on the characteristics. Therefore, as the cable becomes relatively hot and shrinkage / expansion of the insulating oil occurs relatively high, bubbles are likely to occur, and the electric field distributed to the innermost layer 210A of the reinforced insulation layer, which is relatively vulnerable to insulation due to its large electric field strength, is generated. Since it can be alleviated, it is possible to stabilize the insulation performance.

Subsequently, a semiconducting layer which is energized with the outer semiconducting layer 16 of the cable and a metal layer which is energized with the metal sheath 22 of the cable are restored on the reinforcing insulating layer 210 and the protective copper tube 240 is covered. . The protective copper tube 240 may protect the inside of the junction box from the outside, and may be energized with the metal sheath 22 of the cable 100 to serve as a passage for the accident current.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments.

The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (19)

1. In the DC power cable intermediate connection system comprising a pair of DC power cable and the intermediate junction box connecting the DC power cable to each other,

   The DC power cable

   A conductor acting as a passage for current for transmitting power;

   An inner semiconducting layer formed to surround the conductor;

   A cable insulation layer formed on an outer side of the inner semiconducting layer and made of insulating paper impregnated with insulating oil so that current flowing along the conductor does not leak to the outside; And

   An outer semiconducting layer formed to surround the cable insulation layer,

   End portions of the pair of power cables in which the conductor, the inner semiconducting layer, the cable insulation layer and the outer semiconducting layer are sequentially exposed are provided to face each other,

   The intermediate junction box,

   A conductor crimp sleeve that grips the conductors of the pair of power cables and electrically connects each other;

   A reinforcing insulating layer made of insulating paper impregnated with insulating oil and surrounding at least a portion of the conductor or cable insulating layer exposed from the conductor crimp sleeve and the power cable; And

   And a copper powder leakage preventing unit formed between the conductor and the reinforcing insulating layer to prevent copper from flowing out of the conductor.
2. The method of claim 1,

   The copper powder outflow prevention unit,

   A copper powder leakage preventing plate disposed between the conductor compression sleeve and the conductor;

   A first electric field homogenization layer disposed between the conductor crimp sleeve and the conductor or between the reinforcement insulating layer and the conductor;

   A second field uniformity layer disposed between the reinforcement insulating layer and the conductor crimp sleeve, or between the reinforcement insulating layer and the first field uniformity layer; And

   A pressing layer disposed between the reinforcing insulating layer and the conductor crimp sleeve, or between the reinforcing insulating layer and the conductor; DC power cable intermediate connection system comprising a.
3. The method of claim 2,

   The conductor crimp sleeve includes a body portion having at least two wrinkles formed to protrude from an inner surface and at least one wrinkled bone formed between the wrinkles.

   The copper powder leakage preventing plate is disposed between the body portion and the conductor DC power cable intermediate connection system.
4. The method of claim 3,

   The copper powder leakage preventing plate is disposed at one end of the conductor crimp sleeve beyond the corrugated mountain.
5. The method of claim 3,

   The copper powder leakage preventing plate is disposed between the body portion and the conductor so as to extend from one end to the other end of the conductor crimp sleeve.
6. The method of claim 3,

   The copper powder leakage preventing plate is terminated in the longitudinal direction of the conductor DC power cable intermediate connection system.
7. The method of claim 3,

   The copper powder leakage preventing plate is a DC power cable intermediate connection system, characterized in that made of a metal or alloy of the same series as the conductor.
8. The method of claim 3,

   The first electric field uniformization layer is a DC power cable intermediate connection system, characterized in that consisting of a semi-conducting tape transversely spaced apart in the longitudinal direction of the DC power cable.
9. The method of claim 8,

   And the first electric field uniformization layer is formed by transversely winding a semiconductive tape so as to overlap the conductor of the cable in the longitudinal direction of the cable.
10. The method of claim 8,

    And the first electric field uniformizing layer is formed by transversely winding a plurality of semiconductive tapes so as to overlap the conductor of the cable in the longitudinal direction of the cable.
11. The method of claim 2,

    And the at least one portion of the first field homogenization layer and at least a portion of the at least one portion of the same amount of oil leakage preventing plate overlap each other.
12. The method of claim 3,

    And the at least one portion of the at least one portion of the at least one portion of the at least one portion of the at least one portion of the at least one portion of the at least one portion of the first electric field homogenization layer is overlapped with each other in the corrugation of the conductor crimp sleeve.
13. The method of claim 3,

    The copper powder leakage preventing unit overlaps each other between the one end of the conductor crimp sleeve and the vertex of the corrugated mountain formed on one end of the conductor crimp sleeve.
14. The method of claim 2,

    The first electric field uniformization layer is a DC power cable intermediate connection system, characterized in that formed continuously extending from the inner semiconducting layer of the cable.
15. In accordance with claim 2,

    And a second electric field homogenization layer surrounding the first electric field homogenization layer on an outer surface of the conductor crimp sleeve.
16. The method of claim 15,

    The second electric field homogenization layer is a DC power cable intermediate connection system, characterized in that formed of a semi-conducting tape pleated.
17. The method of claim 2,

    The copper powder outflow prevention unit,

    And a pressurized layer formed to surround the first electric field homogenization layer, the copper powder leakage preventing plate, the conductor crimp sleeve, and the second electric field homogenization layer.
18. The method of claim 17,

    DC presser cable intermediate connection system, characterized in that the pressing layer is made of insulating paper.
19. The method of claim 18,

    And the pressurized layer has a volume resistance of 10 ² or more lower than that of the reinforcement insulating layer.

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