KR20180111457A - Jointing power cable system using joint box - Google Patents

Abstract

The present invention relates to an intermediate connection system of a DC power cable, capable of precisely controlling the shape of both ends of a junction box. The intermediate connection system of a DC power cable includes a pair of DC power cables including a conductor, an internal semiconducting layer, a cable insulation layer, and an external semiconducting layer, and the junction box for connecting the pair of DC power cables.

Description

[0001] The present invention relates to a DC power cable intermediate connection system,

The present invention relates to a DC power cable intermediate connection system.

Generally, a power cable is used to power a desired location through the ground, ground, or seabed using a power-supplying conductor.

The power cables are connected by a joint box at intervals of several hundreds of meters or tens of kilometers and the ends of the power cables are connected to the processing power transmission lines by a termination connection box. When the power cable is connected to the intermediate junction box, the conductor is first connected in a state where the insulation layer of the cable is exposed, and the reinforcing insulation layer is formed on the surface of the insulation layer by inserting the insulation paper impregnated in the high viscosity insulation oil. In this case, the insulation paper is supported while applying the insulating oil on the way of winding the insulating paper, that is, between the insulating paper, and then the outer semiconductive layer, metal sheath, and the like are restored.

In order to secure a sufficient interface length in consideration of the surface electric field at the interface between the insulating layer of the cable and the connection box insulating layer to be restored in the intermediate connection box, . That is, each end of the cable insulation layer is exposed so as to have an inclined surface, and both end portions of the connection box insulation layer restored in the intermediate connection box are formed to have inclined surfaces corresponding to the respective ends of the cable insulation layer. At this time, since the interface between the cable insulation layer and the insulation layer restored in the intermediate connection has a great influence on the insulation performance of the intermediate connection box, it needs to be formed precisely.

The geometry of the insulation layer restored in the intermediate connection box is closely related to the control of the electric field acting on the intermediate connection box as well as the interface between the cable insulation layer and the insulation layer restored in the intermediate connection, It is necessary to precisely control and form the geometrical shape of the insulating layer restored in the recess.

An object of the present invention is to provide a DC power cable intermediate connection system capable of precisely controlling the shape of both side ends of an intermediate connection box.

A DC power cable intermediate connection system according to an embodiment of the present invention includes a pair of DC power cables having a conductor, an inner semiconductive layer, a cable insulation layer, and an outer semiconductive layer, and a pair of DC power cables In the DC power cable intermediate connection system including the intermediate connection box, the pair of DC power cables are provided such that the respective ends of the conductor, the inner semiconductive layer, the cable insulating layer and the outer semiconductive layer, which are sequentially exposed, The intermediate connection box includes: a conductor connection portion electrically and mechanically connecting the exposed pair of conductors; A first reinforcing insulating layer having an insulating paper wound around the conductor connecting portion, the exposed inner semiconductive layer and the cable insulating layer to form an outer diameter of the cable insulating layer and having inclined surfaces at both ends in the longitudinal direction; A reinforcing insulation layer and a slope portion surrounding the exposed cable insulation layer and having a straight portion having a constant width in the cable longitudinal direction and a slope portion formed at both ends of the straight portion and having a width in the cable longitudinal direction reduced in a radial direction of the cable A reinforcing insulating layer including a second reinforcing insulating layer; And a connection half external conductive layer formed along the outer surface of the slope portion of the second reinforcing insulation layer and having a slope shape by itself and made of a semiconductive material, wherein the first reinforcing insulation layer and the second reinforcing insulation layer Wherein each of the first reinforcing insulating layer and the second reinforcing insulating layer is composed of a plurality of insulating ground layers laminated in the radial direction, and the first reinforcing insulating layer or the second reinforcing insulating layer has a wide width winding portion formed with a wide width and a wide width winding portion contacting the wide width winding portion, And a three-width wind-up portion composed of an insulating paper having a width smaller than that of the insulating paper making up the portion.

In the present invention, each of the insulating layer layers having an outer diameter smaller than that of the insulating layer constituting the outermost layer among the plurality of insulating layer layers of the second reinforcing insulating layer may include at least one or more triangular winding sections and a wide-width winding section.

In the present invention, the triple winding portion is formed so as to be transversely overlapped or spaced in the longitudinal direction of the cable in the same triple winding portion, and may be laminated in the radial direction of the cable.

In the present invention, in each of the insulating layer layers having an outer diameter smaller than that of the insulating layer constituting the outermost layer of the plurality of insulating layer layers of the second reinforcing insulating layer, both side surfaces of the triangular winding portion can be in contact with the light-

Each of the insulation layer layers having an outer diameter larger than that of the insulation layer constituting the innermost layer among the plurality of insulation layer layers of the first reinforcing insulation layer may include at least one or more triangular winding sections and a wide-width winding section.

In the present invention, the cable insulation layer has a slope-shaped end portion, and the first reinforcing insulating layer has a slope surface corresponding to the slope-shaped end portion, and the slope surface Side.

In the present invention, it is preferable that the cable insulation layer has a slope-shaped end portion in a multi-step slope shape, the first reinforcing insulation layer has a plurality of slope surfaces corresponding to the end portions of the slope shape, And an outer surface of the witch winding part

In the present invention, a plurality of insulating layers having an outer diameter smaller than that of the insulating layer constituting the outermost layer of the second reinforcing insulating layer and having an outer diameter larger than that of the insulating layer constituting the outermost layer of the first reinforcing insulating layer Each of the insulating layers has an buttock having an interface formed by contacting the other of the plurality of light-windings in the same insulating layer, and the number of the windings in the insulating layer is the same May be less than or equal to the number.

In the present invention, the insulating layer constituting the innermost layer of the first reinforcing insulating layer may be composed of only the triple winding portion.

In the present invention, the insulation layer constituting the innermost layer of the first reinforcing insulation layer may have a smaller volume resistivity than the insulation layer adjacent thereto.

In the present invention, the insulating layer constituting the innermost layer of the first reinforcing insulating layer may be formed of kraft paper.

In the present invention, the triangular winding portion of the second reinforcing insulating layer may be located in the straight line portion without being located in the slope portion.

In the present invention, the three reinforcing insulation layers of the first reinforcing insulation layer or the second reinforcing insulation layer may be composed of a single narrow width region or a twin narrow width region, and the single narrow width region may have a width And the cross-sectional area of the cross-sectional area may be a cross-sectional area of two or more narrow widths different in width from each other.

In the present invention, the conductor connecting portion may include: a conductor crimping sleeve for holding and electrically connecting the conductors of the pair of power cables; And a copper spill preventing portion formed between the reinforcing insulating layer and the conductor to prevent the copper powder from flowing out of the conductor.

In the present invention, the copper leakage preventing portion may include a copper leakage preventing plate disposed between the conductor pressing sleeve and the conductor, the copper leakage preventing plate comprising a metal or an alloy of the same kind as the conductor; A first electric field smoothing layer disposed between the conductor compression sleeve and the conductor or between the reinforcing insulation layer and the conductor, the first electric field smoothing layer being formed by horizontally inserting a semiconductive tape so as to overlap in a longitudinal direction of the cable at a portion in contact with the conductor; And a second electric field smoothing layer disposed between the reinforcing insulating layer and the conductor compression sleeve, or between the reinforcing insulating layer and the first electric field uniforming layer.

In the present invention, the conductor compression sleeve includes a body portion having at least two corrugated protrusions formed on the inner surface and at least one corrugated bone formed between the corrugated grains, May be disposed between the conductors, and may be disposed beyond the corrugation.

In the present invention, at least a part of the first leakage preventing plate and the first electric field equalizing layer may overlap with each other in the corrugation of the conductor compression sleeve.

In the present invention, the counterflow leakage preventing portion may be formed such that the ends of the first flow field uniforming layer and the first flow field blocking layer overlap each other between the one end of the conductor crimping sleeve and the vertex of the corrugated mountain formed on one side of the conductor crimping sleeve .

According to an embodiment of the present invention, a slope-type interface between the cable insulation layer and the first reinforcing insulation layer is precisely formed, and the slope portion of the second reinforcing insulation layer is precisely controlled to improve the insulation performance of the intermediate connection box have.

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 box;
3 is a cross-sectional view showing the first reinforcing insulating layer and the second reinforcing insulating layer of the intermediate connection box shown in FIG. 2 in more detail.
FIG. 4 is an enlarged view of FIG. 2C. FIG.
Fig. 5 is a cross-sectional view showing a conductor compression sleeve after compression. Fig.
Figure 6 is a cross-sectional view schematically showing the intermediate connection box shown in Figure 2;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals designate like elements throughout the specification.

Generally, the insulating oil impregnated cable is connected by an intermediate connection box at intervals of several hundred meters or several kilometers, and the end of the insulating oil impregnated cable is connected to the working line by the termination connection port. Hereinafter, the construction of the dielectric-oil-impregnated power cable will be described first, and the connection process of the connection box will be described.

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

1, a power cable 100 includes a conductor 11, an inner semiconductive layer 12, a cable insulation layer 14, and an outer semiconductive layer 16, And the cable core portion 10 for preventing electric current from leaking in the cable radial direction.

The conductor 11 serves as a passage through which a current flows to transmit electric power and is made of a material having excellent conductivity and strength and flexibility suitable for cable manufacturing and use such as copper or aluminum ≪ / RTI >

1, the conductor 11 is provided with a circular central wire element 11a and a flat wire element layer 11C composed of a rectangular wire element 11b stranded to surround the circular central wire element 11a May be a rectangular conductor having an entirely circular cross section, and as another example, it may be a circular compression conductor in which a plurality of circular element wires are twisted and compressed in a circular shape. The rectangular conductor has an advantage that the outer diameter of the cable can be reduced because the dot rate is relatively higher than that of the circular compressed conductor.

Since the conductor 11 is formed by twisting a plurality of elemental wires, the surface of the conductor 11 may not be smooth and the 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 cable insulation layer 14 described later, the insulation performance may be deteriorated.

In order to solve the above-mentioned problems, an inner semiconductive layer 12 may be formed outside the conductor 11. The inner semiconductive layer 12 may have semiconducting properties by adding conductive particles such as carbon black, carbon nanotube, carbon nanoplate, or graphite to the insulating material.

The inner semiconductive layer 12 functions to stabilize the insulation performance by preventing a sudden change in the electric field between the conductor 11 and the cable insulation layer 14 described later. In addition, by suppressing the uneven distribution of electric charge on the conductor surface, it is possible to make the electric field uniform and prevent the gap between the conductor 11 and the cable insulation layer 14 from being formed, thereby suppressing the corona discharge and dielectric breakdown do.

The cable insulation layer 14 is provided on the outer side of the inner semiconductive layer 12 to electrically isolate the cable insulation layer 14 from the outside so that a current flowing along the conductor 11 does not leak to the outside.

The cable insulation layer 14 may be formed of insulating paper impregnated with insulating oil. That is, the cable insulation layer 14 may be formed by winding up insulation paper in multiple layers so as to surround the inner semiconductive layer 12 and impregnating the insulation oil after the cable core is formed. As the insulating oil is absorbed by the insulating paper, the insulating property of the cable insulating layer 14 can be improved.

The insulating oil is filled in gaps between the voids inside the insulating paper and the gap formed between the layers formed by winding the insulating paper to improve the insulating property and reduce the frictional force between the insulating paper at the time of bending the cable to improve the bending property of the cable. Although the kind of the insulating oil is not particularly limited, it should be in contact with copper or aluminum constituting the conductor 11 and not be oxidized by heat. It is preferable that the insulating paper be impregnated at an impregnation temperature, for example, It is preferable to use a medium-viscosity insulating oil having a sufficiently low viscosity and a kinematic viscosity at 60 DEG C of 10 to 500 centistokes or a high-viscosity insulating oil having a kinematic viscosity at 60 DEG C of 500 centistokes or more.

In the case of using a low-viscosity insulating oil having a relatively low viscosity, it is necessary to pressurize the insulating oil using a lubricating device or the like in order to keep the insulating paper impregnated with the insulating oil and prevent the gap from being generated in the cable insulating layer due to the flow of the insulating oil There is a need. However, when medium viscosity or high viscosity insulating oil is used, the flow of insulating oil is small, so there is no need for an oil supply device for pressurizing the insulating oil, or the number of required oil supply facilities can be reduced, thereby extending the cable extension length. For example, the insulating oil may be at least one insulating oil selected from the group consisting of naphthenic insulating oil, polystyrene insulating oil, mineral oil, alkylbenzene, polybutene-based synthetic oil, heavy alkaline,

The insulating paper may be a kraft paper in which kraft pulp is used as a raw material and an organic electrolyte in the pulp is removed, or a composite insulating paper in which a kraft paper is adhered to one side or both sides of a plastic film. The plastic film has a resistivity higher than that of the kraft paper adhered to one side or both sides thereof, so that even if bubbles are generated in the kraft paper due to the flow of the insulating oil during the impregnation process or cable operation, the voltage distributed to the bubbles can be relaxed, A polyolefin resin such as polypropylene or polybutylene, a tetrafluoroethylene-hexafluoropropylene copolymer, an ethylene-tetrafluoroethylene copolymer, an ethylene-tetrafluoroethylene copolymer, And a polypropylene homopolymer resin which is excellent in heat resistance.

Specifically, the cable insulation layer 14 can be formed by winding up a kraft and impregnating the insulation oil. In this case, the insulating oil may flow in the direction of the cable load, and the gap may be generated. On the other hand, when the composite insulating paper is wound and impregnated with the insulating oil to form the cable insulating layer 14, the thermoplastic resin such as the polypropylene resin is not impregnated with the insulating oil, and the impregnation temperature at the time of cable production, Thermal expansion is caused by operating temperature. When the thermoplastic resin thermally expands, a surface pressure is applied to the laminated kraft paper, thereby narrowing the passage of the insulating oil. Therefore, the flow of the insulating oil due to the gravity or the shrinkage / expansion of the insulating oil according to the temperature can be suppressed. In addition, the composite insulating paper has an advantage of being able to reduce the outer diameter of the cable because the dielectric insulating strength is higher than that of the craft paper.

On the other hand, when the power cable is energized, heat is generated in the conductor serving as a passage through which the current flows, and the temperature gradually decreases from the inside toward the outside in the cable radial direction, Occurs. Therefore, the insulation oil of the cable insulation layer, that is, the cable insulation layer formed on the inner semiconductive layer 12, which belongs to the conductor directly above the section, moves to the outside due to low viscosity and thermal expansion, The viscosity of the insulating oil is increased and it does not return to the original state, so that voids may be generated in the portion of the cable insulation layer in the region directly above the conductor.

In addition, a high electric field acts on the cable insulation layer, that is, the cable insulation layer formed in the direction of the outer semiconductive layer 16, which belongs to the section under the metal sheath where the electric field gradually increases due to the temperature difference. The conductor straight section and the metal sheath lower section have a high possibility of occurrence of voids and can act as an insulation weak portion which is a starting point of partial discharge and dielectric breakdown as a region where a high electric field acts in accordance with a temperature change in the cable.

In order to solve the above-described problems, only a kraft may be used as an insulating paper in the area of the cable insulation layer 14 including the insulation weak portion. That is, the cable insulation layer 14 is divided into the first cable insulation layer, the second cable insulation layer, and the third cable insulation layer in the direction of the outer semiconductive layer 16 described later from the inner semiconductive layer 12, Only the kraft may be used for the cable insulation layer and / or the third cable insulation layer, and the composite insulation paper may be used for the second cable insulation layer.

In this case, a difference in resistivity occurs between the second cable insulating layer on which the composite insulating paper is wound and the first cable insulating layer and / or the third cable insulating layer on which the kraft paper is wound, and the cable insulation layer The first cable insulation layer and / or the third cable insulation layer of the second insulation layer 14 has a relatively low resistivity and functions to alleviate an electric field shared among the insulation fragile portions. Specifically, a high electric field acts on the second cable insulating layer on which the composite insulating paper having a 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 cable insulating layer and / A relatively low electric field acts on the conductor straight section and / or the metal sheath lower section included in the insulation layer, so that the electric field acting on the insulation weak portion is relaxed and the insulation performance can be stabilized.

In addition, the cable insulation layer 14 may form the third cable insulation layer to be thicker than the first cable insulation layer. In the case of forming a metallic sheath 22 described later on the outside of the cable insulation layer 14 or restoring the metallic sheath 22 after connecting two power cables exposed sequentially from the inside of the cable core portion The second cable insulation layer may be formed to have a larger thickness than the first cable insulation layer so that the second cable insulation layer 14 may be deformed, It is preferable to protect the plastic film from heat. In this case, the thickness of the first cable insulation layer can be selected in consideration of the impulse surge voltage required for the power cable and the like.

The outer semiconductive layer 16 may be provided outside the cable insulation layer 14. The outer semiconductive layer 16 is formed of a material having semiconducting properties by adding conductive particles such as carbon black, carbon nanotube, carbon nanoplate, graphite and the like to an insulating material such as an inner semiconductive layer, Uneven charge distribution between the layer 14 and the metal sheath 22 described later is suppressed to stabilize the insulation performance. In addition, the outer semiconductive layer 16 functions to smooth the surface of the cable insulation layer 14 in the cable so as to prevent corona discharge by alleviating electric field concentration, and to physically protect the cable insulation layer 14 Can be performed. The outer semiconductive layer 16 may further include a metalized paper. The metalized sheet may be formed by laminating an aluminum foil on a kraft paper, and a plurality of perforations may be present to facilitate impregnation of the cable insulating layer 14 with insulating oil.

The cable core portion 10 may further include a water absorbing portion 21 for preventing water from penetrating into the cable. The moisture absorbing portion can be formed between the stranded strands of the conductor 11 and / or the outside of the conductor 11. The water absorbing portion can absorb the moisture penetrated into the cable at a high speed, Tape, a coating layer or a film including a super absorbent polymer (SAP) so as to prevent moisture from penetrating in the longitudinal direction of the cable. In addition, the water absorbing part may have a semiconductive property to prevent a sudden change in the electric field.

A cable protecting portion 20 is provided outside the cable core portion 10 and a power cable installed in the seabed may further include a cable covering portion 30. The cable protector and cable protector protects the core from various environmental factors such as moisture penetration, mechanical trauma, and corrosion which may affect the power transmission performance of the cable.

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

The metallic sheath 22 may be formed so as to surround the core portion 10. In particular, when the power cable is installed in an environment such as a seabed, the cable core portion 10 may be sealed to prevent foreign matter such as moisture from entering the cable core portion 10, The melted metal is extruded outside the cable core portion 10 so as to have a continuous outer surface having no seams, so that the order performance can be improved. Lead or aluminum is used as the above metal. In the case of a power cable installed on the seabed, it is preferable to use lead having excellent corrosion resistance against seawater. To compensate for mechanical properties, It is more preferable to use a lead alloy. The metal sheath 22 serves as a passage through which a fault current flows when a ground fault or a short circuit occurs in the ground at a power cable end, protects the cable from external impacts, and prevents an electric field from being discharged to the outside of the cable .

The metal sheath 22 may be coated with a corrosion inhibiting compound such as a blown asphalt or the like in order to further improve the corrosion resistance, water repellency and the like of the cable and improve the adhesive strength with the polymer sheath 24 .

In addition, a copper wire-directing tape or a moisture absorbing layer 21 may be additionally provided between the metal sheath 22 and the cable core portion 10. The copper wire direct tape is composed of a copper wire and a nonwoven tape and acts to smooth electrical contact between the outer semiconductive layer 16 and the metal sheath 22. The moisture absorbing layer absorbs moisture penetrating the cable A tape, a coating layer or a film including a super absorbent polymer (SAP) excellent in the ability to maintain the absorbent state at a high speed and to prevent moisture from penetrating in the cable longitudinal direction It plays a role. The copper wire-directing tape and the water-absorbing layer preferably have a semiconducting property in order to prevent a sudden change in the electric field, and may include a copper wire in the water-absorbing layer so as to be capable of both conducting and absorbing water.

The polymer sheath 24 is formed outside the metal sheath 22 to improve the corrosion resistance and water repellency of the cable and to protect the cable from mechanical damage and other external environmental factors such as heat and ultraviolet rays . The polymer sheath 24 may be formed of a resin such as polyvinyl chloride (PVC), polyethylene or the like. In the case of a power cable installed in the seabed, it is preferable to use a polyethylene resin having excellent water repellency. In the environment, polyvinyl chloride resin is preferably used.

The power cable 100 includes a metal reinforcing layer 26 made of a steel cap or the like galvanized on the inner side or the outer side of the polymer sheath so that the metal sheath 22 expands due to expansion of the insulating oil . The upper and / or lower portions of the metal reinforcing layer 26 may be provided with a bedding layer (not shown) made of a semiconductive nonwoven tape or the like to buffer an external force applied to the power cable, and may be made of polyvinyl chloride or polyethylene It is possible to further improve the corrosion resistance, water resistance and the like of the power cable, and further protect the cable from other external environmental factors such as mechanical trauma and heat and ultraviolet rays.

In addition, the power cable installed on the seabed may be easily damaged by an anchor or the like of a ship, and may be damaged by a bending force due to currents or waves, a frictional force with the sea floor, etc. Therefore, (30) may be additionally provided.

The cable sheathing may include an armor layer 34 and a covering layer 38. The armor layer 34 may be composed of at least one layer made of steel, zinc-plated steel, copper, brass, bronze, etc., And performance as well as additional protection from external forces.

Polypropylene yarn or the like is formed in one or more layers on the upper and / or lower portions of the armor layer 34 to protect the cable, and the serving layer 34 formed at the outermost portion is formed of a color Can be made of two or more different materials to ensure the visibility of the cable installed at the seabed.

2 and 3 are partial cutaway views schematically showing an intermediate connection box according to the present invention and a DC power cable intermediate connection system connecting a pair of power cables using the same. 1 is a partial cut-away view schematically showing a state in which DC power cables 100A and 100B having the configuration shown in Fig. 1 are connected to each other by an intermediate connection box 200. Fig.

2 and 3, the pair of direct current power cables 100A and 100B (in which the conductors 11a, the inner semiconductive layer 12, the cable insulating layer 14 and the outer semiconductive layer 16 are sequentially exposed) , A reinforcing insulating layer (210) formed so as to surround the conductor connecting portion, a reinforcing insulating layer (210) surrounding the reinforcing insulating layer And a connection hermetic outer semiconductive layer 230 which is electrically connected to the outer semiconductive layer 16 or the metal sheath 22 of the cable.

The conductor connecting portion electrically connects the exposed pair of conductors electrically and mechanically, and connects the pair of conductor ends by a conductor pressing sleeve 1P. Alternatively, the conductor connecting portion may be provided between the pair of conductor ends Filler metal can be filled and connected.

The conductor crimping sleeve 1P fixes the ends of the pair of conductors 11a and 11b to each other so that even if tensile force is applied when the power cable or the power cable intermediate connection system is installed, And firmly supports the electrically connected state. In the case of using the conductor compression sleeve 1P, it is possible to press the outer surface of the conductor compression sleeve after inserting the conductor compression sleeve at each end of the exposed pair of conductors 11a, 11b, The conductor connecting portion can be formed by pressing the outer surface and then machining such as grinding to smooth the outer surface. Further, the outer diameter of the conductor crimping sleeve after being compressed may be a crimp sleeve substantially similar to the outer diameter of the exposed pair of conductors 11a and 11b.

The filler metal may be formed of a filler metal material having a diameter larger than the diameter of the conductors 11a and 11b by a joining process such as brazing or arc welding between a pair of conductor ends, ) Is melted and then machined by grinding or the like, so that it can be filled between the pair of conductor ends.

When the filler metal is filled and the grinding is performed or when the surface of the sleeve is compressed after finishing the compacting sleeve, the conductor connecting portion has substantially the same outer diameter as that of the cable conductor, so that the reinforcing insulating layer The thickness can be reduced.

A reinforcing insulating layer 210 for covering at least a part of the cable insulating layer 14A including the conductor connecting portion after connecting the conductors 11a and 11b of the insulating oil-impregnated cables 100A and 100B by forming the conductor connecting portion, So that a current flowing through the conductor and the conductor connecting portion flows only in the longitudinal direction of the intermediate connection system and prevents leakage in the radial direction.

The cable insulation layer 14A may be exposed by being pen-sled to have a multi-stage structure. As shown in FIGS. 2 and 3, the cable insulation layer 14A has a multi-stage structure including a first pen sling end 14A1, a second pen sling end 14A2, and a third pen sling end 14A3, As shown in FIG. In addition, when the cable insulation layer is composed of the first cable insulation layer, the second cable insulation layer and the third cable insulation layer 14A3 as described above, the first penling end 14A1 is connected to the first cable insulation And the second pen sling end (14A2) is made of the second cable insulating layer, and the third pen sling end (14A3) is made of a part of the second cable insulating layer And the third cable insulation layer.

The reinforcing insulating layer 210 may be formed by winding insulating paper so as to surround the conductor connecting portion, the exposed inner semiconductive layer, or the cable insulating layer. The insulating paper constituting the reinforcing insulating layer 210 may have a high dielectric strength And may further include an insulating paper such as a kraft paper having a volume resistivity lower than that of the composite insulating paper, for example, a kraft paper, so that electric field control using the difference in volume resistivity between the composite insulating paper and the kraft paper can be performed. In addition, the insulating paper is preferably impregnated with insulating oil.

The reinforcing insulating layer 210 includes a first reinforcing insulating layer 2101 on which an insulating paper is wound to surround the conductor connecting portion, the exposed inner semiconductive layer to the cable insulating layer, and the outer diameter of the cable insulating layer is formed, And an insulating layer 2101 and a second reinforcing insulating layer 2102 formed to surround the first reinforcing insulating layer.

The second reinforcing insulating layer 2102 is formed to surround the first reinforcing insulating layer 2101 and the exposed cable insulating layer 14A. That is, the second reinforcing insulating layer 2102 is formed at an outer diameter or greater of the cable insulating layer to improve the insulation performance of the intermediate connection box.

The second reinforcing insulating layer 2102 has a straight portion 2102A having a width in the cable longitudinal direction that is constant in the radial direction of the cable and a second reinforcing insulating layer 2102B formed at both ends of the straight portion, And a slope portion 2102B that decreases in the radial direction of the cable.

The slope portion 2102B is formed at both ends of the rectilinear portion 2102A and functions to control an electric field by determining a shape of a connection case external semiconductive layer 230 to be described later. Specifically, the width in the cable longitudinal direction is formed so as to decrease in the radial direction of the cable, and the thickness of the slope portion increases from the end of the cable toward the end of the straight line side. Further, the rate of increase of the thickness may be increased, and in this case, the slope portion may have an outer surface formed of a curved surface. That is, the slope portion 210B can be formed so that the inclination of the outer surface of the slope portion gradually increases toward the end portions of the cable conductors 11a and 11b.

The second reinforcing insulating layer 2102 may be formed of a plurality of insulating ground layers 2102L stacked in the radial direction as shown in FIG. 3, and the insulating ground layer 2102L may be formed by winding insulating paper, And laminating insulating paper in the radial direction of the connection box.

The plurality of insulating ground layers 2102L means that the insulating paper having a predetermined length is formed of an insulating ground layer which is not continuous in the longitudinal direction of the insulating paper and is divided in the radiation direction of the cable to the intermediate connection port. Specifically, one insulating paper layer may be formed by using one piece of insulating paper roll having a predetermined length and wound in the longitudinal direction of the insulating paper. When all the insulating paper having the predetermined length is wound, A process of winding the insulating paper using a roll to form another insulating paper layer is repeated, and a plurality of insulating paper layers are formed by using a plurality of insulating paper rolls. Therefore, each of the insulating layer layers 2102L is divided into the radial direction of the cable or the intermediate connection box because the wound insulation paper is not continuous. The one insulating paper roll may have a substantially trapezoidal shape in which the width of the insulating paper roll is narrow or wide. The insulating paper making up each of the plurality of insulating paper rolls may have a different rate of change in width or a different length of insulating paper . That is, since a plurality of insulating ground layers 2102L are formed by using insulating paper having various shapes, the shape of the second reinforcing insulating layer 2102, particularly, the shape of the slope portion 2102B can be precisely controlled.

The second reinforcing insulating layer 2102 may include a plurality of insulating paper take-up portions W and N that are not continuous in the longitudinal direction of the cable or the connection box in the same insulating layer. That is, one insulating layer 2102L may be divided into a plurality of insulating paper winding portions W, N in the longitudinal direction of the cable. In the second reinforcing insulating layer 2102 including insulating paper impregnated with insulating oil, the plurality of insulating paper winding portions W, N serve as an insulating oil flow path. Particularly, when the insulating paper is a composite insulating paper including a plastic film, the insulating oil can not flow through the plastic film, so that when the insulating oil is inflated upon impregnation with the insulating oil or heat, There is an advantage.

In the present invention, the insulating paper winding sections (W, N) can be in contact with other insulating paper winding sections on at least one of the upper surface, the lower surface and the side surface. Specifically, the insulator paper take-up portion can be in contact with the insulator winding portion of another insulation layer at the upper surface or lower surface, or can contact the other insulator winding portion of the same insulation layer at the side surface. At this time, the insulating paper wound portion is wound in the longitudinal direction and the radial direction of the cable so that the insulating paper winding portion having a width significantly smaller than that of the other insulating paper winding portion constituting the same layer, particularly the insulating paper winding portion contacting the side surface, (N), and includes an insulating paper having a significantly larger width than the insulating paper constituting the triple winding section (N), the insulating paper The insulating paper take-up unit can be defined as a wide-area take-up unit (W).

The second reinforcing insulating layer 2102 may include the triple winding portion N and the wide portion winding portion W to precisely shape the slope portion 2102B. In particular, among the plurality of insulating ground layers constituting the second reinforcing insulating layer 2102, each of the insulating ground layers having an outer diameter smaller than that of the insulating ground layer forming the outermost layer of the second reinforcing insulating layer, And the shape of the slope portion 2102B of the second reinforcing insulating layer 2102 can be precisely formed by the at least one triple winding winding portion N. [

Specifically, after a plurality of wafers W are formed on the slope portion and a part of the rectilinear portion by winding the wafers, the empty space formed between the wafers W is wound with a small width to form a three- The winding portion N can be formed.

The wide-width take-up portion W can be formed by winding a substantially trapezoidal wide-width paper to form a predetermined shape of the insulator paper take-up portion, in particular, a predetermined shape of the outer surface of the slope surface with a predetermined slope . Therefore, the workability is excellent, and the outer surface shape of the slope portion 2102B can be precisely controlled by forming the slope portion 2102B by winding the wide span.

However, when an error occurs in the process of winding the wide band, it is not possible to form the insulator winding portion having a predetermined shape in the empty space formed between the wide band winding portions W. Therefore, it is preferable that the thin wire winding portion N is formed by winding the thin wire in the longitudinal direction and the radial direction of the cable by horizontally inserting the thin wire in an empty space formed between the wide width winding portions W. [ That is, the three-dimensional winding section N formed between the wide-area winding sections W forming a predetermined type of insulated-sheet winding section is traversed in such a manner that the insulating paper having a small width is overlapped or spaced in the longitudinal direction of the cable, And the area where the insulating paper having a small width is overlapped or spaced is adjusted to compensate an error occurring in forming the optical fiber winding portion W and precisely control the shape of the second reinforcing insulating layer have.

The widthwise winding portion N is formed by winding up an insulating paper having a width smaller than that of the wide width paper in the longitudinal direction and the radial direction of the intermediate connection. The width of the insulating paper wound in the longitudinal direction is large, It is dense. The gap is highly likely to act as a gap which can be a point of time of dielectric breakdown. If the gap is densely packed, there is a possibility that an electric field distortion occurs due to a local change in volume resistivity. Therefore, it is preferable that the triple winding take-up portion N is formed not only on the slope portion 2102B but on the straight portion 2102A in which the insulating paper is wound up relatively thick.

In addition, each insulating layer of the slope portion 2102B may be formed of one wide-width winding portion W. That is, the slope portion 2102B may not be provided with the buttress portion C where the optical fiber winding portion W and the optical fiber winding portion W contacting the optical fiber winding portion W meet. The slope portion 2102B, The winding portion W may extend to the straight portion 2102A of the second reinforcing insulating layer 2102. [ There may be a gap between the insulating paper of the wide-width take-up portion W and the insulating paper of the wide-width paper take-up portion in contact with the insulating paper, and the gap can act as a gap, and the butt portion C is relatively thickly wound It is preferable to form only the straight portion 2102A.

As described above, the triangular winding portion N can form the shape of the second reinforcing insulating layer precisely, but may act as an insulating weak portion. Therefore, each of the insulating layer 2102L of the second reinforcing insulating layer 2102 can minimize the number of the three-corner winding portions N so that the number of the three-corner winding portions N becomes equal to or less than the number of the butted portions C. The butt portion C refers to an interface where different width wirings W contact with each other in the same insulation layer 2102L.

However, the outermost insulation layer of the second reinforcing insulating layer 2102 may not be equal to or less than the number of the counter winding portions C in the number of the winding wirings N. That is, if the length of the outermost insulating layer of the second reinforcing insulating layer 2102 is short, the insulating layer may be formed only by the wider portion W, or the two wider portions W and / And only one triangular winding portion N formed between the two wide-width winding portions.

In other words, each of the insulation layer having an outer diameter smaller than that of the outermost insulation layer of the second reinforcing insulation layer 2102 and having an outer diameter larger than that of the outermost insulation layer of the first reinforcing insulation layer, The number of the three-corner winding portions may be smaller than or equal to the number of the butt portions in the same insulating layer. As described above, the insulation layer 2102L is formed by minimizing the width W of the winding portion N, which is relatively weak in insulation compared with the width W of the windings W, so that the insulation performance of the second reinforcing insulation layer 2102 can be improved have.

The first reinforcing insulating layer 2101 is formed up to the outer diameter of the cable insulating layer so as to surround the conductor connecting portion, the exposed inner semiconductive layer and the cable insulating layer. Specifically, the first reinforcing insulating layer 2101 is formed by horizontally inserting insulating paper in a space between the cable insulating layers exposed in the pair of cables provided so as to face each other, winding the insulating paper in the longitudinal direction of the cable, And the like.

3, the first reinforcing insulating layer 2101 may be formed of a plurality of insulating ground layers 2102L laminated in a radial direction, and the insulating ground layer 2102L may be formed by winding insulating paper, And laminating insulating paper in the radial direction of the connection box.

In addition, the first reinforcing insulating layer 2101 may include a plurality of insulating paper winding portions W, N in which the insulating paper is not continuous in the longitudinal direction of the cable or the connection box in the same insulating paper layer, The reinforcing insulating layer 2102 may include the triple winding portion N and the wide portion winding portion W so that the shape of the slope portion 2102B can be precisely realized.

Specifically, one insulating layer 2102L may be divided into a plurality of insulating paper winding portions W and N in the longitudinal direction of the cable. In the first reinforcing insulating layer 2101 including insulating paper impregnated with insulating oil, the plurality of insulating paper winding portions W, N serve as an insulating oil flow path. Particularly, when the insulating paper is a composite insulating paper including a plastic film, the insulating oil can not flow through the plastic film, so that when the insulating oil is inflated upon impregnation with the insulating oil or heat, There is an advantage.

The insulating paper winding portions W and N can be in contact with other insulating paper winding portions on at least one of the upper surface, the lower surface and the side surface. Specifically, the insulator paper take-up portion can be in contact with the insulator winding portion of another insulation layer at the upper surface or lower surface, or can contact the other insulator winding portion of the same insulation layer at the side surface. At this time, the insulating paper wound portion is wound in the longitudinal direction and the radial direction of the cable so that the insulating paper winding portion having a width significantly smaller than that of the other insulating paper winding portion constituting the same layer, particularly the insulating paper winding portion contacting the side surface, (N), and includes an insulating paper having a significantly larger width than the insulating paper constituting the triple winding section (N), the insulating paper The insulating paper take-up unit can be defined as a wide-area take-up unit (W).

The first reinforcing insulating layer 2102 may include the triple winding portion N and the wide portion winding portion W so that the shape of the slope portion 2102B can be precisely realized. In particular, among the plurality of insulating ground layers constituting the first reinforcing insulating layer 2102, each of the insulating ground layers having an outer diameter larger than that of the insulating layer constituting the innermost layer of the first reinforcing insulating layer, And the slope portion 2102B of the first reinforcing insulating layer 2102 can be precisely formed.

Meanwhile, the first reinforcing insulating layer 2101 may have inclined surfaces S at both ends in the longitudinal direction. Since the first reinforcing insulating layer 2101 is formed in a space between the cable insulating layers exposed in the pair of cables opposing each other, both longitudinal ends of the first reinforcing insulating layer 2101 are exposed And the end of the cable insulation layer may be formed to correspond to the slope shape. When the end portion of the cable insulation layer has a multi-step slope shape as shown in FIGS. 2 and 3, a plurality of inclined surfaces S are formed at the end of the first reinforcing insulation layer 2101 so as to correspond to the multistage slope shape of the cable insulation layer, The interfacial length between the first reinforcing insulating layer 2101 and the cable insulating layer 14A can be increased to improve the insulating performance.

However, the inclined surface S is an insulative weak portion having an insulating performance, and it is necessary to enhance insulation performance by winding the insulating paper with a strong tension. At this time, when a strong tension is applied to the wide insulating paper to form the inclined surface, wrinkles may occur on the wide insulating paper. Therefore, it is preferable to form the three-width wound portion made of the insulating paper having a narrow width, and to wind the insulating paper with a strong tension.

Specifically, the first reinforcing insulating layer 2101 may be formed to be spaced apart from the slope-shaped end of the cable by a predetermined distance, and the thin wire winding portion may be formed in the spaced-apart space. That is, it is preferable that the inclined plane S of the first reinforcing insulating layer corresponding to the slope-shaped end of the cable is formed of the outer surface of the triangular winding portion.

At this time, the wide-width winding portion can form an insulating paper winding portion having a predetermined shape as described above, which is advantageous in workability. However, when an error occurs in the process of forming the wide-width wound portion, an insulated-paper take-up portion having a predetermined shape is formed in the empty space between the inclined face S and the wide- It is difficult to do. Therefore, it is preferable to form the triangular winding portion N by winding the thin wire in the longitudinal direction and the radial direction of the cable in the hollow space.

That is, the triple winding portion N is formed by winding the insulating paper in the radial direction so that the insulating paper overlaps or is spaced apart in the longitudinal direction of the cable, and the area where the insulating paper having the small width is overlapped or spaced is adjusted Thereby correcting an error generated in forming the optical fiber winding portion W and precisely controlling the shape of the second reinforcing insulating layer. In addition, the widthwise winding portion may be formed in a space between the inclined plane S and the wide-width winding portion spaced apart from the inclined plane S by a predetermined distance. As shown in FIGS. 2 to 3, when the first reinforcing insulating layer has a plurality of inclined surfaces, it is preferable that the triangular winding portions are formed on each of the plurality of inclined surfaces.

Therefore, by forming the three-width-wise wind-up portion wound on the slant surface in the longitudinal direction and the radial direction of the cable, the width of which is considerably smaller than that of the wide-width paper, by forming the wide-width winding portion by winding the wide- , The insulating performance can be improved and the shape of the inclined surface can be precisely controlled.

Among the plurality of insulating ground layers forming the first reinforcing insulating layer 2102, the insulating layer forming the innermost layer of the first reinforcing insulating layer may be formed only of the triple winding portion. An insulation layer constituting the innermost layer of the first reinforcing insulation layer is formed at a distance from the conductor connection portion. The conductor connection portion may have a non-smooth surface in the process of connecting the pair of conductors to each other, . In particular, when the conductor connection portion includes a conductor compression sleeve, the conductor compression sleeve may have a thickness greater than a predetermined level to enhance the mechanical performance of the conductor connection portion, thereby causing a height difference from the conductor, Lt; / RTI >

It is very difficult to uniformly wind the non-smooth surface or the insulating paper having a wide width to the stepped portion. If the wide-width winding portion is formed, the insulating oil may not be impregnated or the dielectric fluid There is a possibility of occurrence of voids. Therefore, it is preferable that the insulating layer constituting the innermost layer of the first reinforcing insulating layer is formed only of the triple winding portion.

However, the triangular winding portion can act as an insulation weak portion as described above. When the insulating layer constituting the innermost layer of the first reinforcing insulating layer, which is the portion to which the high electric field is applied when the cable is energized, is formed by only the triangular winding portion, there is a fear that the insulation performance is lowered. Therefore, it is preferable that the insulation layer constituting the innermost layer of the first reinforcing insulation layer has a smaller volume resistivity than the other insulation layer adjacent thereto. Specifically, it is preferable that the insulation layer constituting the innermost layer of the first reinforcing insulation layer is formed of kraft paper, and the other insulation layer adjacent thereto is formed of composite insulation paper.

Due to the characteristics of DC power transmission having a resistive field distribution characteristic in which an electric field is distributed according to the volume resistivity, a large electric field is allocated to another insulation layer adjacent to the insulation layer constituting the innermost layer of the first reinforcing insulation layer having a relatively low resistivity So that the insulation performance can be improved.

The triangular reinforcements of the first reinforcing insulating layer to the second reinforcing insulating layer may be composed of a single narrow width earth and / or a twin narrow width gap. Here, a single three-wide section is a section of a three-width winding section (N), which has a width of a certain width, and a three-wide section is a section of two or more widths different in width. In the case of forming the three different width sections made of the narrow widths different from each other, the gap between the insulating paper is reduced as compared with the case of forming the three-width winding section N with a constant width, It has excellent workability.

On the other hand, as the current flows through the cable, the conductor in the cable is heated to decrease the viscosity of the dielectric oil in the cable, so that the copper between the conductor wires can move in the direction of gravity. The copper particles flowing in the gravity direction can be flowed out to the reinforcing insulating layer. In particular, there is a problem that insulation breakdown occurs in the copper powder flowing out to the insulating layer constituting the innermost layer of the first reinforcing insulating layer composed of only the three- .

Therefore, the conductor connecting portion may further include a counterflow preventing portion PC for preventing the copper from flowing out from the conductor, and the counterflow preventing portion PC may be formed between the reinforcing insulating layer and the conductor . Hereinafter, the above-mentioned copper leakage preventing portion PC will be described in detail with reference to FIGS. 4 and 5. FIG.

The outflow leakage preventing portion PC includes a copper leakage preventing plate 211 disposed between the conductor pressing sleeve and the conductor and made of a metal or an alloy of the same kind as the conductor and between the conductor crimping sleeve and the conductor Or a first electric field uniforming layer (212) disposed between the reinforcing insulating layer and the conductor and formed by horizontally inserting a semiconductive tape in a longitudinal direction of the cable in a portion contacting the conductor, and a reinforcing insulating layer And a second electric field smoothing layer (213) disposed between the sleeve or between the reinforcing insulating layer and the first electric field uniforming layer.

As described above, the outer surface of the conductor compression sleeve 1P is pressed to grip a pair of conductors. Accordingly, it is possible to include a body portion having at least one corrugation 1Pa 'protruding from the inner surface by compression and at least one corrugation 1Pb formed between the corrugation, Can be defined as a ridge (T).

The copper spill preventing plate 211 may be disposed between the conductor crimping sleeve 1P and the conductors 11A and 11B. That is, the copper leakage preventing plate 211 is disposed inside the conductor crimping sleeve 1P and may not extend beyond the end of the conductor crimping sleeve 1P. As another example, the counterflow leakage preventing plate may extend not only between the conductor crimping sleeve 1P and the conductor 11A but also beyond both ends of the conductor crimping sleeve 1P.

The copper leakage preventing plate 211 may be made of a material having a dense structure such that the copper can not permeate, and may preferably be formed of a metal material capable of withstanding a force acting upon pressing the pressing sleeve. The copper leakage preventing plate 211 may be made of copper, aluminum, a copper alloy, or an aluminum alloy so as to correspond to the material of the conductors 11A and 11B of the cables 100A and 100B. As an example, a copper tape may be applied and brazed. In the case where both ends of the copper tape are soldered to form the copper portion leakage preventing plate 211, it is preferable that the soldering portion is smoothly processed so that no edge is generated.

The outflow route of the copper foil generated in the conductor 11A formed so as to enclose the cable conductor 11A by the tangs between the conductor crimping sleeve 1P and the conductor 11A is minimized So that the copper powder can be cut off by the copper spill preventing plate 211.

The copper spill preventing plate 211 which faces the end of the cable conductor 11A is connected to the corrugated web 1Pb 'beyond the corrugated sheet 1Pa' formed on the inner side by pressing the conductor crimp sleeve 1P To the other end a2 of the first cable insulation layer 14A1 starting from the one end a1 of the conductor crimping sleeve 1P to receive the pressing force from the conductor crimping sleeve 1P. For example, as shown in FIG. 5, the flow dividing plate 211 preferably extends beyond the ridge T, which is the highest point in the ridge 1Pa '. The other end a2 of the copper flow-out prevention plate 211 that faces the first cable insulation layer 14A1 of the cable may protrude from the conductor compression sleeve 1P and may not act as an edge.

The first electric field equalization layer 212 may be disposed between the conductor compression sleeve and the conductor, and between the reinforcing insulation layer and the conductor. That is, the first electric field equalizing layer 212 may extend not only between the first reinforcing insulating layer 2101 and the conductor 11A, but also between the conductor crimping sleeve 1P and the conductor 11A, Can be extended to just before the highest ridge (T) in the acid (1 Pa 'in Fig. 5). By extending in this way, a sufficient current path can be ensured between the conductor 11A of the cable and the conductor crimping sleeve 1Pa.

The first electric field equalizing layer 212 may be formed by extending the inner semiconductive layer of the cable 100A as an example. That is, the first electric field uniforming layer 212 can be formed as the inner semiconductive layer itself of the cable 100A and is removed with a predetermined length without being removed together with the cable insulation layer, The conductor 11A is exposed.

The first electric field uniforming layer 212 may be formed of a semiconductive tape and may perform the same function as the inner semiconductive layer of the cable described above. At the same time, the semiconductive tape 212 contacts the conductor in the longitudinal direction of the cable Thereby making it possible to prevent the outflow of the above-mentioned copper powder.

Specifically, at the portion in contact with the conductor, at least one semi-conductive tape is laminated on the conductor 11A by wrapping one semiconductive sheet in the longitudinal direction of the DC power cables 100A and 100B . Further, the plurality of semiconductive tapes may be formed in a cross-wound manner so as to overlap with each other in the longitudinal direction of the cable, thereby improving workability.

The first leakage preventing plate 211 and the first electric field equalizing layer 212 may be overlapped with each other at a corrugated surface T of the conductor crimping sleeve. Preferably, the one end of the conductor crimping sleeve, (T) of corrugated acid (1Pa ') formed on one end side of the sleeve, and more preferably between one end of the conductor crimp sleeve and the corrugated mountain formed on one end side of the conductor crimp sleeve The end portion of the first electric field uniforming layer 212 may overlap with the end portion of the first anti-scattering plate 211 between the ridges T. That is, the first electric field uniforming layer 212 may be formed on the ridge T and the end portion of the first electric field equalization layer and the flow blocking plate 211 are connected to one end of the conductor crimping sleeve and the conductor crimping One end side of the sleeve The first electric field smoothing layer 212 and the conductor compression sleeve 1P are overlapped with each other between the ridges T of the corrugated mountain formed on the first electric field equalization layer 212, And the conductor 11A are strongly adhered to each other.

The second electric field equalizing layer 213 is made of a semiconductive material and is disposed between the first reinforcing insulating layer 2101A and the first electric field equalizing layer 212 or between the first reinforcing insulating layer 2101A, And is formed between the compression sleeve 1P. In particular, the second electric field uniforming layer 213 smoothens the outer surface of the conductor compression sleeve, which becomes non-uniform after finishing, to uniform the electric field acting on the outer surface. The semiconductive tape may be formed by winding the semiconductive tape, the first electric field smoothing layer 212, the conductor compression sleeve 1P, and the conductor 11A, It is possible to minimize the flow of the molten copper that is wound up.

The intermediate connection box and the intermediate connection system using the intermediate connection box may further include a connection box external semiconductive layer 230. The connection box outer semiconductive layer 230 is formed to surround the reinforcing insulation layer 210 and is energized with the outer semiconductive layer 16 or the metal sheath 22 of the cable.

The connection box outer semiconductive layer 230 is formed along the outer surface of the slope portion 2102B of the second reinforcing insulating layer 2102 and has a slope shape itself, Consecutive equipotential lines may be distributed according to the geometric shape of the junction box outer semiconductive layer 230 having a slope shape. In addition, the connection box outer semiconductive layer 230 may have a lower volume resistance than the cable insulation layers 14A and 14B and the reinforcing insulation layer 210. That is, the electric field distribution can be controlled by using the slope shape and the volume resistivity of the connection box external semiconductive layer 230.

The connection box outer semiconductive layer 230 may be formed by winding a semiconductive tape around the outer surface of the slope portion 2102B of the second reinforcing insulating layer and may be energized with the outer semiconductive layer 16 of the cable. And may be formed so as to surround the straight portion 2102A of the second reinforcing insulating layer 2102. [

A metal shielding layer electrically connected to the metal sheath 22 of the cable 100A is restored on the reinforcing insulating layer 210 and the spacer 250 and the protective copper pipe 240 are covered.

The metal shielding layer is formed so as to surround the slope portion 2102B, the straight portion 2102A of the second reinforcing insulating layer, and the connection semiconductive outer layer 230 of the connection port.

The metal shielding layer formed to surround the slope portion 2102B of the second reinforcing insulating layer is preferably formed of a metal wire. The metal wire may be copper wire, peristaltic wire, tinned copper wire or the like, and the metal wire may be wound around the slope part 2102B or may be formed by winding a braid made of the metal wire. Since the slope portion 2102B has a slope-like outer surface whose slope may not be constant, the metal sheath or the braid can be used to smoothly conduct the connection between the connection semiconductive outer semiconductive layer 230 and the metal shielding layer . Further, since the insulating oil can penetrate between the metal wires, it is easy to impregnate the insulating oil, which will be described later.

6, the intermediate connection box may include a metal shielding layer that surrounds the straight portion 2102A of the second reinforcing insulating layer, and the metal shielding layer 250 may include a metal tape, ≪ / RTI > The straight portion 2102B of the second reinforcing insulating layer having a relatively smooth outer surface can be bonded with a metal plate and bonded, or the metal tape can be wound to improve workability. However, the metal tape or the metal plate may be perforated in order to facilitate impregnation with insulating oil to be described later.

The spacer 250 has a disk shape having a through hole therein, may be made of a metal such as aluminum, and is formed on a straight portion of the second reinforcing insulating layer. The spacer may be fitted outside the reinforcing insulating layer 210 through the through hole to maintain a gap between the copper pipe 240 and the reinforcing insulating layer 210, which will be described later. 6, the spacer 250 may have a plurality of recesses 251 spaced apart from one another in the radial direction. The insulating oil in the copper pipe 240 passes through the concave portion 251. That is, the insulating oil injected into the copper pipe 240 when the insulating oil is impregnated can smoothly move in the longitudinal direction of the intermediate connection box 200 through the concave portion 251. In addition, metal wires may be wound on both sides of the spacer 250 to prevent the spacer 250 from moving due to the flow of the insulating oil.

A metal shield layer protecting portion 270 may be further formed between the metal shield layer 260 and the spacer 250. The metal shield layer protecting part 270 is formed by winding an insulating paper on the metal shielding layer 260 and prevents the metal shielding layer 260 from being damaged by the spacer 250. In detail, when the spacer 250 is fitted outside the reinforcing insulating layer 210, scratches may be generated on the surface of the metal shielding layer 260 formed on the reinforcing insulating layer 210, The metal shield layer 260 may be pressed by the spacer 250 to generate an edge portion. Accordingly, the metal shield layer protecting part 270 is formed between the spacer 250 and the metal layer to prevent the metal shield layer 260 from being damaged by the spacer 250, It is possible to prevent the electric field concentration by this.

The protective copper tube 240 is then covered. The protective copper pipe 240 protects the inside of the connection box from the outside and is energized with the metal sheath 22 of the cable 100 to serve as a path for the fault current.

On the other hand, the intermediate connection system needs to inject insulation oil into the intermediate connection box to ensure insulation performance. Specifically, in the case where the space between the reinforcing insulating layer and the protective copper tube is filled with insulating oil, and in particular, when the reinforcing insulating layer is formed by winding the semi-oil immersion, the reinforcing insulating layer is impregnated with insulating oil to improve the insulating performance There is a need.

The protective copper pipe 240 of the present invention may include an insulating oil inflow pipe and an insulating oil discharge pipe. The inlet pipe and the outlet pipe are formed on the outer surface of the protective copper pipe 240 in opposite directions, and serve as passages through which the insulating oil moves.

The insulating oil supplied into the protective copper pipe through the inlet pipe is discharged to the outside through the upper discharge pipe while impregnating the reinforcing insulating layer 210 through the outer semiconductive layer and the metal shielding layer. Further, by pressurizing the insulating oil using nitrogen gas or the like, the reinforcing insulating layer can be impregnated smoothly, thereby improving the insulating performance.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

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

The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: Cable
11: Conductor
12: inner semiconductive layer
14: Insulating layer
16: outer semiconductive layer
200: Medium connection
210: reinforced insulation layer
230: Outer sheath layer

Claims (18)

1. A direct current power cable intermediate connection system comprising a pair of direct current power cables each having a conductor, an inner semiconductive layer, a cable insulation layer and an outer semiconductive layer, and an intermediate connection box connecting the pair of direct power cables to each other,
Wherein the pair of DC power cables are provided such that the respective ends of the conductor, the inner semiconductive layer, the cable insulating layer, and the outer semiconductive layer, which are sequentially exposed,
The intermediate junction box includes:
A conductor connecting portion electrically and mechanically connecting the exposed pair of conductors;
A first reinforcing insulating layer having an insulating paper wound around the conductor connecting portion, the exposed inner semiconductive layer and the cable insulating layer to form an outer diameter of the cable insulating layer and having inclined surfaces at both ends in the longitudinal direction; A reinforcing insulation layer and a slope portion surrounding the exposed cable insulation layer and having a straight portion having a constant width in the cable longitudinal direction and a slope portion formed at both ends of the straight portion and having a width in the cable longitudinal direction reduced in a radial direction of the cable A reinforcing insulating layer including a second reinforcing insulating layer; And
A second reinforcing insulating layer formed on the outer surface of the slope portion and having a slope shape by itself and having a connection box outer semiconductive layer made of a semiconductive material,
Wherein each of the first reinforcing insulating layer and the second reinforcing insulating layer comprises a plurality of insulating ground layers laminated in the radial direction,
Wherein the first reinforcing insulating layer or the second reinforcing insulating layer comprises a wide width winding portion formed with a wide width and a three width winding portion made of an insulating paper having a width smaller than that of the insulating paper constituting the wide width winding portion, Wherein the DC power cable intermediate connection system comprises: The method according to claim 1,
Wherein each of the insulation layer layers having an outer diameter smaller than that of the insulation layer forming the outermost layer of the plurality of insulation layer layers of the second reinforcing insulation layer includes at least one or more triangular winding sections and a wide- Connection system. 3. The method of claim 2,
Wherein the triple winding portion is formed so as to be transversely overlapped or spaced in the longitudinal direction of the cable within the same triple winding portion, and laminated in the radial direction of the cable. The method of claim 3,
Wherein each of the insulation layer having an outer diameter smaller than that of the insulation layer constituting the outermost layer of the plurality of insulation layer layers of the second reinforcing insulation layer contacts both side surfaces of the thin- Connection system. The method according to claim 1,
Wherein each of the insulation layer layers having an outer diameter larger than that of the insulation layer constituting the innermost layer of the plurality of insulation layer layers of the first reinforcing insulation layer includes at least one or more triangular winding sections and a wide- Connection system. 6. The method of claim 5,
Said cable insulation layer having a sloped end,
Wherein the first reinforcing insulating layer has an inclined surface of a shape corresponding to the end of the slope,
And the inclined surface comprises an outer surface of the triangular winding portion. The method according to claim 6,
Wherein the cable insulation layer has a slope-shaped end portion in a multi-step slope shape,
Wherein the first reinforcing insulating layer has a plurality of inclined surfaces corresponding to the ends of the slope shape,
And each of the plurality of inclined planes comprises an outer surface of the triangular winding portion. 8. The method according to any one of claims 2 to 7,
Each of the plurality of insulating ground layers having an outer diameter smaller than that of the insulating layer constituting the outermost layer of the second reinforcing insulating layer and having an outer diameter larger than that of the insulating layer constituting the outermost layer of the first reinforcing insulating layer, A plurality of buttress winding sections in the same insulation layer are formed in the same insulation layer so that the number of the three winding sections in the same insulation layer is smaller than or equal to the number of the buttocks in the same insulation layer, Wherein the DC power cable is connected to the DC power cable. 9. The method of claim 8,
Wherein the insulation layer constituting the innermost layer of the first reinforcing insulating layer comprises only a triple winding portion. 10. The method of claim 9,
Wherein the insulation layer constituting the innermost layer of the first reinforcing insulation layer has a smaller volume resistivity than the insulation layer adjacent thereto. 11. The method of claim 10,
Wherein the insulating layer constituting the innermost layer of the first reinforcing insulating layer is made of kraft paper. 12. The method of claim 11,
Wherein the third reinforcing insulation portion of the second reinforcing insulation layer is located at the straight line portion, not at the slope portion. 13. The method of claim 12,
Wherein the three reinforcing insulation layers of the first reinforcing insulation layer or the second reinforcing insulation layer are composed of a single narrow width earth or a twin narrow width gap,
The single narrow width region is a section of the three-width winding portion,
Wherein the heterogeneous narrow width region is a section where the width of the triangular winding portion is differentiated by two or more thin widths different from each other. 10. The method of claim 9,
The conductor connecting portion includes:
A conductor crimping sleeve for holding and electrically connecting the conductors of the pair of power cables; And
And a copper leakage preventing portion formed between the reinforcing insulating layer and the conductor to prevent a copper powder from flowing out of the conductor. 15. The method of claim 14,
The above-
A copper leakage preventing plate disposed between the conductor pressing sleeve and the conductor, the copper leakage preventing plate being made of a metal or an alloy of the same kind as the conductor;
A first electric field smoothing layer disposed between the conductor compression sleeve and the conductor or between the reinforcing insulation layer and the conductor, the first electric field smoothing layer being formed by horizontally inserting a semiconductive tape so as to overlap in a longitudinal direction of the cable at a portion in contact with the conductor; And
And a second electric field smoothing layer disposed between the reinforcing insulating layer and the conductor compression sleeve or between the reinforcing insulating layer and the first electric field uniforming layer. 16. The method of claim 15,
Wherein the conductor compression sleeve includes a body portion having at least two corrugated protrusions formed on the inner surface and at least one corrugated portion formed between the corrugated elements,
Wherein the copper leakage preventing plate is disposed between the body portion and the conductor and is disposed to extend beyond the corrugation. 17. The method of claim 16,
Wherein at least part of the first leakage preventing plate is overlapped with at least a part of the first electric field equalizing layer in the corrugation of the conductor crimping sleeve. 18. The method of claim 17,
The counterflow leakage preventing portion is formed such that the end portions of the first flow uniforming layer and the first flow blocking layer overlap with each other between one end portion of the conductor crimp sleeve and the vertex of a corrugated mountain formed on one side of the conductor crimping sleeve. DC power cable intermediate connection system.

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