WO2018182076A1 - Direct current power cable joining system using joint box for power cable and direct current power cable joint method - Google Patents

Direct current power cable joining system using joint box for power cable and direct current power cable joint method Download PDF

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Publication number
WO2018182076A1
WO2018182076A1 PCT/KR2017/003604 KR2017003604W WO2018182076A1 WO 2018182076 A1 WO2018182076 A1 WO 2018182076A1 KR 2017003604 W KR2017003604 W KR 2017003604W WO 2018182076 A1 WO2018182076 A1 WO 2018182076A1
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WO
WIPO (PCT)
Prior art keywords
layer
insulating
paper
cable
insulating layer
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PCT/KR2017/003604
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French (fr)
Korean (ko)
Inventor
채병하
Original Assignee
엘에스전선 주식회사
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Publication of WO2018182076A1 publication Critical patent/WO2018182076A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G15/00—Cable fittings
    • H02G15/08—Cable junctions
    • H02G15/10—Cable junctions protected by boxes, e.g. by distribution, connection or junction boxes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/20—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/02—Disposition of insulation
    • H01B7/0208—Cables with several layers of insulating material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B9/00—Power cables
    • H01B9/02—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients
    • H01B9/027—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients composed of semi-conducting layers

Definitions

  • the present invention relates to a DC power cable intermediate connection system and a DC power cable connection method using an intermediate junction box for power cables.
  • 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.
  • Junction box intermediate junction box
  • the conductors 41A and 41B are first connected in a state where the insulation layer of the cable is exposed and the insulation paper is supported on the surface of the insulation layer. 50), and then the outer semiconducting layer 46, the metal sheath 47, and the like are restored.
  • the first reinforcing insulating layer 51 may be formed up to the outer diameter of the cable insulating layer 44, and the second reinforcing insulating layer 52 may be formed above the outer diameter of the cable for reinforcing insulation performance. have.
  • a protective copper tube 60 is provided to protect the inside of the intermediate junction box from the outside.
  • the intermediate junction box having such a structure is filled with a large amount of insulating oil in the protective copper tube (60).
  • the cable connection system may vibrate as current flows through the cable at high voltage.
  • the intermediate junction box may be gripped and fixed.
  • the length of the intermediate junction box that is, the length of the protective copper tube
  • the space E in which the reinforcing insulation layer is not formed in the protective copper tube increases. This empty space is filled with insulating oil. That is, when the intermediate junction box is gripped than when the intermediate junction box is not held, the length of the protective copper tube 60 must be formed longer to stably hold the intermediate junction box. This increase increases the amount of insulating oil filled in the protective copper tube (60).
  • Insulating oil in the protective copper tube 60 repeatedly causes expansion and contraction of the volume according to the heating cycle of the cable connection system, thereby causing a change in the internal pressure of the intermediate junction box.
  • the protective copper tube 60 or the soft portion protective copper tube and cable Part of the metal sheath joined
  • the protective copper tube 60 or the soft portion is destroyed due to excessive pressure rise or fatigue breakdown of the protective copper tube 60 or the soft portion 61 occurs due to repeated expansion and contraction of the insulating oil, resulting in leakage of the insulating oil and the insulation thereof. There is a problem of being destroyed.
  • the height of the reinforcing insulating layer 50 may be lowered and the height of the protective copper tube 60 may be lowered.
  • the reinforcement insulating layer of the intermediate junction box and the insulating layer 44 of the cable is higher than the case where the reinforcing insulating layer 50 is formed to increase the insulation performance. Since the length of the interface between the 50 must be formed longer, there is a problem in that the length of the intermediate junction as a whole.
  • An intermediate junction box for a power cable includes a pair of DC power cables having a conductor, an inner semiconducting layer, a cable insulation layer, and an outer semiconducting layer and connecting the pair of DC power cables to each other.
  • a DC power cable intermediate connection system comprising an intermediate junction, the pair of DC power cables are provided so that each end of the conductor, the inner semiconducting layer, the cable insulation layer and the outer semiconducting layer are sequentially exposed to each other.
  • the intermediate junction box may include: a conductor connection part for electrically and mechanically connecting the exposed pair of conductors; A first reinforcing insulating layer wound around the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer, and formed up to an outer diameter of the cable insulating layer, and having a sloped surface at both ends in the longitudinal direction, and the first reinforcing layer A straight line portion surrounding the exposed insulation layer and the exposed cable insulation layer and having a constant width in the longitudinal direction of the cable and a slope portion having a width in the longitudinal direction of the cable reduced in the radial direction of the cable are formed at both ends.
  • a reinforcing insulating layer including a second reinforcing insulating layer provided; And a junction box outer semiconducting layer formed along the outer surface of the slope portion of the second reinforcing insulating layer and having a slope shape by itself, and made of a semiconductive material, between the first reinforcing insulating layer and the cable insulating layer.
  • the interface of is made of a single inclined surface
  • the second reinforcement insulating layer is composed of a plurality of insulating paper layer laminated on the first reinforcing insulating layer
  • each of the insulating paper layer is formed of at least one narrow paper is supported by the narrow paper
  • a wide paper winding portion formed by winding a wide paper wider than the narrow paper
  • the insulating paper wound on the first reinforcing insulating layer forms a narrow paper winding portion of the second reinforcing insulating layer. It may be larger than the width of the insulating paper, and may be smaller than the width of the insulating paper forming the wide paper winding of the reinforcing insulating layer.
  • the number of insulating paper layers supported on the first reinforcement insulating layer may be 80% or more of the number of insulating paper layers supported on the cable insulating layer.
  • the narrow paper winding of one of the insulating paper layers in the second reinforcing insulating layer may be spaced apart from the narrow paper winding of the insulating paper layer adjacent to the insulating paper layer by a predetermined distance.
  • the narrow paper winding portion of one insulating paper layer in the second reinforcing insulating layer does not overlap with the narrow paper winding portion of another insulating paper layer positioned on or in contact with the insulating paper layer in the vertical direction. Can be.
  • the distance from the narrow paper winding portion of the insulating paper layer in the second reinforcing insulating layer to the narrow paper winding portion of the other insulating paper layer which is located on or in contact with the insulating paper layer It may be greater than or equal to the shortest distance between the butt portion formed by contacting the wide paper winding portions adjacent to each other in the insulating paper layer in contact with the insulating paper layer and the narrow paper winding portion of the insulating paper layer.
  • the narrow paper winding portion may be located on the straight portion without being located on the slope portion.
  • the slope portion may be made of the wide paper winding portion.
  • the conductor connection portion is a pair of conductors are cut diagonally and the ends are provided facing each other; And it may include a filler metal formed between the end of the conductor.
  • a pair of conductors exposed from the cable and the ends are provided facing each other; And a conductor crimp sleeve surrounding the pair of conductor ends, wherein the conductor crimp sleeve may have the same outer diameter as the outer diameter of the conductor.
  • the DC power cable connecting method includes a conductor, an inner semiconducting layer, a cable insulation layer, and an outer semiconducting layer, and the conductor, the inner semiconducting layer, the cable insulation layer, and the outer semiconducting layer are sequentially exposed.
  • a method of connecting a pair of DC power cables provided so that the respective ends thereof face each other comprising: electrically and mechanically connecting the exposed pair of conductors to each other to form a conductor connection; Forming a first reinforcing insulating layer by winding insulating paper to the outer diameter of the cable insulating layer so as to surround the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer; Forming a second reinforcing insulating layer by winding insulating paper to surround the first reinforcing insulating layer and the exposed cable insulating layer; And forming a junction box outer semiconducting layer surrounding the outer surface of the second reinforcing insulating layer, wherein the forming of the second reinforcing insulating layer comprises: a narrow paper winding part on the first reinforcing insulating layer; Stacking a plurality of insulating paper layers including a wide paper winding portion formed of an insulating paper having a width larger than that of the narrow paper wind
  • the forming of the first reinforcing insulating layer, the insulating paper is semi-immersion immersion, it can be wound at least 80% of the number of layers of the insulating paper wound on the cable insulation layer.
  • the forming of the second reinforcement insulating layer may include: forming a narrow paper winding portion of the insulating paper layer of the second reinforcing insulating layer by a predetermined distance from the narrow paper winding portion of the insulating paper layer adjacent to the insulating paper layer. Can be spaced apart.
  • the forming of the second reinforcing insulating layer may include forming a narrow paper winding portion of one of the insulating paper layers of the second reinforcing insulating layer and the narrow paper winding portion of the other insulating paper layer positioned in contact with the insulating paper layer. It can be arranged so that they do not overlap.
  • the forming of the second reinforcement insulating layer may include: forming a third paper winding portion of one of the insulating paper layers of the second reinforcing insulating layer on the insulating paper layer or below the other insulating paper layer.
  • the spaced distance to the winding paper winding portion may be arranged to be greater than or equal to the shortest distance between the butt portion formed by the adjacent wide paper winding portions in contact with the insulating paper layer and the narrow paper winding portion of the insulating paper layer. Can be.
  • the forming of the second reinforcement insulating layer may not include the narrow paper winding part on the slope part.
  • the forming of the second reinforcement insulating layer may include disposing only the wide winding portion in the slope portion.
  • the forming of the metal shielding layer may include forming a metal wire to surround the slope of the second reinforcing insulating layer, and forming the perforated metal plate to surround the straight portion of the second reinforcing insulating layer. It may include.
  • the forming of the metal shielding layer may be terminated and joined so that the perforated metal plate surrounds the straight portion.
  • the forming of the spacer may include a through hole having an inner diameter larger than an outer diameter of the second reinforcement insulating layer therein, and a recessed portion facing the through hole at an outer portion thereof,
  • the insulating oil in the copper pipe can flow in the longitudinal direction of the intermediate junction can be arranged in a straight portion of the second reinforcing insulating layer.
  • the forming of the conductor connection may include filling filler metal between a pair of conductor ends exposed from the cable so that the ends thereof face each other.
  • the step of forming the conductor connecting portion, the conductor crimp sleeve is disposed so as to surround each end of the pair of conductors exposed from the cable so that the ends are opposed to each other, and crimp the outer surface of the conductor crimp sleeve
  • the outer diameter of the conductor crimp sleeve may be the same as the outer diameter of the conductor.
  • the height of the second reinforcing insulating layer to reduce the size of the copper tube to reduce the amount of insulating oil in the protective copper tube can be.
  • FIG. 1 is a cross-sectional view schematically showing a cable connected by a conventional intermediate junction box.
  • FIG. 2 is a perspective view showing an internal configuration of a power cable.
  • FIG 3 is a partial cutaway view schematically showing a cable connected by an intermediate connection.
  • FIG. 4 is a cross-sectional view illustrating in detail the first reinforcing insulating layer and the second reinforcing insulating layer of the intermediate junction box shown in FIG. 3.
  • FIG. 5 is a cross-sectional view schematically illustrating the intermediate junction box shown in FIG. 3.
  • 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.
  • 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.
  • FIG. 2 is a partially cutaway perspective view illustrating an internal configuration of an ultra high voltage direct current power cable.
  • the power cable 100 includes a conductor 11, an inner semiconducting layer 12, a cable insulation layer 14, and an outer semiconducting layer 16, along a cable length direction along the conductor 11. It is provided with a cable core portion 10 that transmits power only in such a way that a current does not leak in the cable radial direction.
  • 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.
  • 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 surround 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.
  • 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.
  • the insulation performance may be reduced.
  • 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 functions to stabilize the insulation performance by preventing a sudden electric field change between the conductor 11 and the cable insulation layer 14 to be 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 cable insulation layer 14 is prevented from forming so as to suppress corona discharge and insulation breakdown. do.
  • the cable insulation layer 14 is provided outside the inner semiconducting layer 12 to electrically insulate the outside from the current flowing along the conductor 11 so as not to leak to the outside.
  • the cable insulating layer 14 may be formed of insulating paper impregnated with insulating oil. That is, the cable insulating layer 14 may be formed by winding insulating paper in multiple layers so as to surround the internal semiconducting layer 12, and then impregnating the cable core with an insulating oil. As the insulating oil is absorbed into the insulating paper as described above, the insulating property of the cable insulating layer 14 may be improved.
  • the insulating oil is filled in the gaps 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.
  • 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.
  • 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.
  • the cable insulation layer 14 may be formed by winding only the kraft and impregnating the insulation oil.
  • the insulating oil flows in the cable load direction, and voids may occur.
  • the thermoplastic resin such as the polypropylene resin is not impregnated with the insulating oil, the impregnation temperature at the time of cable production or at the time of cable operation Thermal expansion occurs depending on the operating temperature.
  • 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.
  • the composite insulating paper has a higher insulation strength than kraft paper has the advantage of reducing the cable outer diameter.
  • the insulating oil of the cable insulating layer ie, the cable insulating layer formed on the inner semiconducting layer 12, which belongs to the upper section of the conductor is lowered in viscosity and thermally expands to move outward, and moves when the cable temperature falls.
  • the viscosity of the insulating oil becomes high and does not return to the original state, voids may occur in a portion of the cable insulating layer in the section immediately above the conductor.
  • a high electric field acts on the cable insulation layer formed in the direction of the outer semiconducting layer 16, which belongs to the cable insulation layer directly below the metal sheath, in which the electric field is gradually reversed according to the temperature difference and the electric field gradually increases.
  • 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.
  • the kraft may be used as the insulating paper in the area including the weak insulation of the cable insulating layer (14). That is, the cable insulation layer 14 is divided into a first cable insulation layer, a second cable insulation layer, and a third cable insulation layer in a direction from the inner semiconducting layer 12 to the outer semiconducting layer 16 described later. Only kraft may be used for the cable insulation layer and / or the third cable insulation layer, and the composite insulation may be used for the second cable insulation layer.
  • a resistivity difference occurs between the second cable insulation layer wound with the composite insulation paper and the first cable insulation layer and / or the third cable insulation layer wound with the kraft paper, and the cable insulation layer wound with the kraft paper having a low resistivity (
  • the first cable insulation layer and / or the third cable insulation layer of 14) has a relatively low resistivity, and serves to alleviate an electric field distributed to the weak insulation portion.
  • a high electric field acts on the second cable 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 cable insulating layer and / or the third cable Since a relatively low electric field acts on the section immediately above the conductor and / or the section directly below the metal sheath included in the insulating layer, the electric field acting on the weak part of the insulation can be alleviated to stabilize the insulation performance.
  • the cable insulation layer 14 may form a third cable insulation layer thicker than the first cable insulation layer.
  • the metal sheath 22, which will be described later, is formed on the outside of the cable insulation 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 losing heat is applied to the second cable insulating layer of the cable insulating layer 14 to cause deformation of the plastic film, the second cable insulating layer is formed by forming a second cable insulating layer thicker than the first cable insulating layer. It is desirable to protect the plastic film from heat. In this case, the thickness of the first cable insulation 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 cable insulation 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. The nonuniform charge distribution between the layer 14 and the metal sheath 22 described later is suppressed to stabilize the insulation performance.
  • the outer semiconducting layer 16 smoothes the surface of the cable insulating layer 14 in the cable to mitigate electric field concentration to prevent corona discharge, and also physically protects the cable insulating layer 14. Can be done.
  • the outer semiconducting layer 16 may further include a metallized paper.
  • the metallized paper may be formed by stacking a thin aluminum film on kraft paper, and a plurality of perforations may exist to facilitate the impregnation of the insulating film of the cable 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.
  • 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.
  • the power cable when 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.
  • 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.
  • 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.
  • an anti-corrosion compound for example, blown asphalt, etc.
  • 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.
  • 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 formed of a galvanized steel tape or the like on the inside or the outside of the polymer sheath so that the metal sheath 22 is expanded by the expansion of the insulating oil. You can prevent it.
  • 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.
  • 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. 3 is a partial cutaway view schematically showing an intermediate junction box according to the present invention and a DC power cable intermediate connection system connecting a pair of power cables using the same.
  • it is a partial cutaway view schematically showing a state in which the DC power cables 100A and 100B having the configuration as shown in FIG. 1 are connected to each other by the intermediate junction box 200.
  • ends of the pair of DC power cables 100A and 100B in which the conductor 11A, the inner semiconducting layer 12, the cable insulation layer 14, and the outer semiconducting layer 16 are sequentially exposed are provided to face each other, a conductor connecting portion connecting the ends of the pair of conductors 11A and 11B to each other, a reinforcing insulating layer 210 formed to surround the conductor connecting portion, and formed to surround the reinforcing insulating layer.
  • An intermediate junction box including a junction box outer semiconducting layer 230 that is energized with the outer semiconducting layer 16 to the metal sheath 22 of the cable is formed.
  • the conductor connection part electrically connects the exposed pair of conductors electrically and mechanically, and fills and connects the filler metal (M) between the pair of conductor ends, or connects the pair of conductors using a conductor crimp sleeve.
  • the conductor end can be gripped and connected.
  • the filler metal (M) is larger than the diameter of the conductors (11A, 11B) by using a bonding process such as brazing or arc welding between the pair of conductor ends provided with diagonally cut ends facing each other. (Filler metal) can be melted and glued and then machined such as grinding to fill between the pair of conductor ends.
  • the conductor crimp sleeve may be a copper crimp sleeve whose outer diameter after being crimped is approximately similar to that of the exposed pair of conductors 11A and 11B, and the exposed pair of conductors ( 11A, 11B) by inserting a conductor crimp sleeve at each end of the conductor crimp sleeve can be formed by crimping the outer surface of the conductor crimp sleeve, and the outer surface of the conductor crimp sleeve is crimped and then machined such as grinding to smooth the outer surface. Can be.
  • the conductor crimp sleeve fixes the ends of the pair of conductors 11A and 11B to each other so that the pair of conductors are electrically connected to each other even when tension is applied when the power cable to the power cable intermediate connection system are installed. I firmly support the state which was made.
  • the conductor connecting portion When the filler metal (M) is filled and ground or the surface is compressed after compressing the copper crimping sleeve, the conductor connecting portion has the same outer diameter as the cable conductor, so the reinforcement formed on the conductor connecting portion The thickness of the insulating layer can be reduced.
  • the exposed cable insulation layer 14A may be penciled to have a single slope.
  • the cable insulation layer 14A may have a single inclined surface S whose angle with the exposed conductor 11A is an obtuse angle.
  • the conductor connecting portion is formed to connect the respective conductors 11A and 11B of the insulating oil impregnated cable 100A and 100B, and then a reinforcing insulating layer 210 covering at least a part of the cable insulating layer 14A including the conductor connecting portion is formed.
  • the current flowing through the conductor and the conductor connecting portion flows only in the longitudinal direction of the intermediate connecting system and prevents leakage in the radial direction.
  • the reinforcing insulating layer 210 may be formed by winding insulating paper to surround the conductor connecting portion, the exposed inner semiconducting layer or the cable insulating layer, and the insulating paper forming the reinforcing insulating layer 210 has excellent insulating strength.
  • the composite insulating paper may further include an insulating paper having a lower volume resistivity than the composite insulating paper, for example, kraft paper, so that electric field control may be performed using a difference in volume resistivity between the composite insulating paper and the kraft paper.
  • the reinforcement insulating layer 210 may include a first reinforcement insulating layer 2101 and a first reinforcement formed by winding insulating paper to surround the conductor connecting portion, the exposed inner semiconducting layer or the cable insulating layer.
  • the insulating layer 2101 and the second reinforcing insulating layer 2102 formed to surround the first reinforcing insulating layer may be formed.
  • the second reinforcement insulating layer 2102 is formed to surround the first reinforcement insulating layer 2101 and the exposed cable insulating layer 14A. That is, the second reinforcement insulating layer 2102 is formed above the outer diameter of the cable insulating layer to improve the insulation performance of the intermediate junction box.
  • the second reinforcement 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 is formed at both ends of the straight portion, and the width of the second reinforcement insulating layer 2102 is in the cable length direction. It may have a slope portion 2102B which decreases in the radial direction of the cable.
  • the slope portion 2102B is formed at both ends of the straight portion 2102A and serves to control the electric field by determining the shape of the junction box outer semiconducting layer 230 to be described later.
  • the width in the longitudinal direction of the cable is formed to decrease in the radial direction of the cable so that the thickness of the slope portion becomes thicker from the end of the cable side toward the end of the straight portion side.
  • the increase rate of the thickness may be increased, and in this case, the slope part may have an outer surface formed as a curved surface. That is, the slope portion 210B may be formed such that the slope of the outer surface of the slope portion increases gradually toward the end direction of the cable conductors 11A and 11B.
  • the second reinforcement insulating layer 2102 may be formed of a plurality of insulating paper layers 2102L stacked in a radial direction, and the insulating paper layer 2102L may be wound around the insulating paper. It can be formed by laminating insulating paper in the radial direction of the cable to the intermediate junction box.
  • the plurality of insulating paper layers 2102L means that the insulating paper having a predetermined length is not formed in the longitudinal direction and is formed of an insulating paper layer which is divided in the radial direction of the cable to the intermediate junction box.
  • one insulating paper layer can be formed by winding the insulating paper using an insulating paper roll in which the insulating paper having a predetermined length is wound in the longitudinal direction. When all the insulating paper having the predetermined length is wound, a new insulating paper roll is again. Repeating the process of forming another insulating paper layer by winding the insulating paper using, to form a plurality of insulating paper layers using a plurality of insulating paper rolls.
  • each of the insulating paper layers 2102L is divided in the radial direction of the cable to the intermediate junction bar because the wound insulating paper is not continuous.
  • the one sheet of insulating paper roll may have an insulating paper having a substantially trapezoidal shape in which the width of the insulating paper roll is narrowed or large, and the insulating paper forming each of the plurality of insulating paper rolls may have a different rate of change of the width or length of the insulating paper.
  • the second reinforcement insulating layer 2102 may include a plurality of insulating paper windings W and N which are separated from each other because the insulating paper is not continuous in the longitudinal direction of the cable or the junction box in the same insulating paper layer. That is, one insulating paper layer 2102L may be divided into a plurality of insulating paper windings W and N in the longitudinal direction of the cable. In the second reinforcement insulating layer 2102 including insulating paper impregnated with insulating oil, the plurality of insulating paper windings W and N serve as an insulating oil flow path.
  • the insulating oil when the insulating paper is a composite insulating paper containing a plastic film, the insulating oil does not flow through the plastic film, the insulating oil may flow between the plurality of insulating paper winding when the insulating oil impregnated to expand the insulating oil by heat.
  • the insulating paper winding portion (W, N) may be in contact with the other insulating paper winding portion on at least one of the upper surface, the lower surface to the side.
  • the insulating paper winding portion may be in contact with the insulating paper winding portion of the other insulating paper layer from the upper surface to the lower surface, or may be in contact with other insulating paper winding portion of the same insulating paper layer from the side.
  • an insulated paper winding part of which an insulated paper winding part constitutes the same layer especially an insulated paper winding having a significantly smaller width than that of the insulated paper winding part which is in contact with the side, is wound in the longitudinal direction and the radial direction of the cable.
  • the insulating paper winding portion may be defined as narrow paper winding portion (N), including an insulating paper having a significantly larger width than the insulating paper forming the narrow paper winding portion (N).
  • the insulated paper winding portion may be defined as the wide paper winding portion (W).
  • the second reinforcement insulating layer 2102 may include the narrow winding portion N and the wide winding portion W to precisely implement the shape of the slope portion 2102B.
  • each of the insulating paper layers having a smaller outer diameter than the insulating paper layer forming the outermost layer of the second reinforcing insulating layer among the plurality of insulating paper layers constituting the second reinforcing insulating layer 2102 is at least one of the wide-wound winding W;
  • One or more narrow paper winding parts N may be formed to precisely implement the shape of the slope part 2102B of the second reinforcement insulating layer 2102.
  • the winding part N can be formed.
  • the wide paper winding portion W may form an insulated paper winding portion having a predetermined shape by winding a wide trapezoidal shape, particularly an insulated paper winding portion having a predetermined slope so that an outer surface of the slope surface has a predetermined slope. . Therefore, it is excellent in workability and can form the slope part 2102B by winding the said wide paper, and can control the external shape of the slope part 2102B precisely.
  • the insulating paper winding portion having a predetermined shape may not be formed in the empty space formed between the wide paper winding portions W. Therefore, it is preferable to form the narrow paper winding portion N by winding the narrow paper horizontally and winding in the longitudinal direction and the radial direction of the cable in the empty space formed between the wide paper winding portions W. That is, unlike the wide paper winding portion W which forms the insulating paper winding portion of a predetermined shape, the narrow paper winding portion N is formed by winding a small width of the insulating paper in the longitudinal direction of the cable and winding in the radial direction.
  • the shape of the second reinforcement insulating layer may be precisely controlled by compensating for an error generated when the wide area winding unit W is formed.
  • the narrow paper winding portion (N) is formed by winding an insulating paper having a relatively smaller width than that of a wide paper paper in the longitudinal and radial directions of the intermediate junction box, and has a large gap between the insulating paper wound in the longitudinal direction. It is concentrated.
  • the gap is likely to act as a gap that can be the point of breakdown, and when the gap is dense, there is a risk of electric field distortion due to a local volume resistivity change may act as an insulation weakening. Therefore, it is preferable that the narrow paper winding portion N is formed only in the straight portion 2102A in which the insulation paper is relatively thickly wound, not the slope portion 2102B.
  • each insulating paper layer of the slope part 2102B may be formed of one wide paper winding part (W). That is, the butt portion C, in which the wide paper winding portion W and the wide paper winding portion W contacting each other, may not be formed in the slope portion 2102B, and the wide paper forming the slope portion 2102B may be formed.
  • the winding part W may extend to the straight portion 2102A of the second reinforcing insulating layer 2102.
  • the narrow paper winding portion N may precisely form the shape of the second reinforcement insulating layer, but may act as an insulating weakening portion. Accordingly, each of the insulating paper layers 2102L of the second reinforcement insulating layer 2102 may have the number of narrow paper winding portions N less than or equal to the butt portion C, thereby minimizing the number of narrow paper winding portions.
  • the butt portion C means an interface where different wide-area winding portions W contact each other in the same insulating tooth layer 2102L.
  • the number of narrow paper winding portions N may not be equal to or less than the number of butt portions C.
  • the insulating paper layer is formed only by the wide paper winding part W, or two wide paper winding parts W and not including butt parts are formed. It may include only one narrow paper winding portion (N) formed between the two wide paper winding portion.
  • the insulation performance of the second reinforcing insulation layer 2102 may be improved by forming the insulation paper layer 2102L with a minimum width of the narrow paper winding portion N, which is relatively weak to insulation, compared to the wide paper winding portion W. have.
  • the second reinforcement insulating layers 2102 are spaced apart from each other by a predetermined distance D1 without overlapping the narrow paper winding portions N1 and N2 formed in the insulating paper layers 212L1 and 212L2 adjacent to each other in the vertical direction. By forming it, it is possible to prevent overlapping of void density generated by winding narrow paper, thereby further improving the insulation performance of the intermediate junction box.
  • the distance D1 spaced apart from each other is a distance D2 between the narrow paper winding portion N1 of the insulating paper layer 2102L1 and the butt portions C1 and C2 of the adjacent insulating paper layer 2102L2. It may be greater than or equal to the shortest distance D2 of D3).
  • the narrow paper of the insulating paper layer 2102L1 is formed.
  • the distance D1 between the winding portion N1 and the narrow paper winding portion N2 of the insulating paper layer 2102L2 adjacent to the insulating paper layer 2102L1 is equal to the narrow paper winding portion N1 of the insulating paper layer 2102L1.
  • the distance may be greater than or equal to the distance between the narrow paper winding of one of the insulating paper layers and the butt portion of the adjacent insulating paper layer.
  • the narrow winding portions of the different insulating paper layers do not overlap each other, but the butt which may serve as the insulating oil flow path is formed close to the narrow paper winding portion, so that the insulating oil is well impregnated in the narrow paper portion. have.
  • the first reinforcing insulating layer 2101 is formed by winding insulating paper to surround the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer, and formed to the outer diameter of the cable insulating layer. Specifically, the first reinforcing insulating layer 2101 is rolled up the insulating paper in the space between the cable insulating layer exposed from the pair of cables provided to face each other, wound the insulating paper in the longitudinal direction of the cable and insulated in the radial direction It can form by laminating
  • the first reinforcement insulating layer 2101 may have slopes S at both ends in the longitudinal direction. Since the first reinforcing insulating layer 2101 is formed in a space between the exposed cable insulating layers of the pair of cables provided to face each other, both ends of the first reinforcing insulating layer 2101 in the longitudinal direction are exposed. It may be formed to correspond to the end shape of the cable insulation layer. 3 and 4, when a single inclined surface is formed at the end of the cable insulation layer, a single inclined surface S is formed at the end of the first reinforcing insulation layer 2101 to correspond to the single inclined surface of the cable insulation layer. By forming, the interface length between the first reinforcing insulating layer 2101 and the cable insulating layer 14A can be increased as compared with the case where there is no inclined surface, so that the insulating performance is improved.
  • the length of the intermediate junction box becomes long, and the length of the intermediate junction box according to the specifications of the customer or the manufacturing unit price cannot be long.
  • the cable insulation layer is penciled to form a multistage inclined surface at the end, and a first reinforcement insulating layer having a multistage inclined surface at the end thereof is provided.
  • the conventional intermediate junction box having a multi-stage inclined surface it has excellent workability, including a wide paper winding unit formed by winding a wide wide paper, and a narrow paper having a significantly smaller width than the wide paper in the longitudinal direction and the radial direction of the cable.
  • the shape of the multi-stage inclined surface can be precisely controlled by forming the wound narrow paper winding portion in the multi-stage inclined surface.
  • the narrow paper winding part is formed by winding an insulating paper having a significantly smaller width than that of a wide paper paper in the longitudinal and radial directions of the intermediate junction box, and there are many gaps between the insulating paper wound in the longitudinal direction, and the gap is densified. .
  • the gap is likely to act as a gap that can be the point of breakdown, and when the gap is densified, the gap may be an insulation weakness that may cause electric field distortion due to a local volume resistivity change. Therefore, the conventional intermediate junction box may have a difference in volume resistivity between the narrow paper winding portion formed along the inclined surface and the portion where the wide paper winding portion is formed, so that the electric field is locally distorted in the multi-stage inclined surface, which may cause insulation breakdown.
  • Intermediate junction may have an inclined surface formed precisely without including a narrow paper winding portion in the first reinforcing insulating layer, it is also excellent workability.
  • the intermediate junction box for a DC power cable can maintain the creeping electric field characteristic of the interface between the inclined surface, in particular, the interface between the cable insulation layer and the first reinforcement insulation layer, while having a relatively short length, and has excellent insulation performance. You can provide the system.
  • the insulating paper forming the first reinforcing insulating layer 2101 is larger than the width of the insulating paper forming the narrow paper winding portion N of the second reinforcing insulating layer 2102, and the second reinforcing insulating layer It may be smaller than the width of the insulating paper forming the wide paper winding W of 2102.
  • the insulating paper may be formed by lateral winding so as to be spaced apart in the cable longitudinal direction.
  • the workability of the insulating paper roll is not only poor.
  • the chance of voids is very high.
  • the wide reinforcement winding portion W of the second reinforcement insulating layer 2102 is larger than the width of the insulating paper forming the narrow paper winding portion N of the second reinforcement insulating layer 2102.
  • the first reinforcement insulating layer 2101 is larger than the width of the insulating paper forming the narrow paper winding portion N of the second reinforcement insulating layer 2102 and the wide paper winding portion of the second reinforcement insulating layer 2102.
  • the insulating paper smaller than the width of the insulating paper forming (W) may be spaced apart in the longitudinal direction of the cable and wound in the longitudinal and radial directions of the cable. That is, a gap Gap is formed between the insulating papers spaced apart in the longitudinal direction of the cable, and the insulating paper is also wound in the cable radial direction to cover the upper and / or lower portions of the gap.
  • the first reinforcing insulating layer 2101 can be formed while controlling the gap between the insulating papers generated when the insulating paper is spaced in the longitudinal direction of the cable, the shape of the first reinforcing insulating layer can be precisely formed. While controllable, since there is no narrow paper winding portion N, it is possible to disperse the voids without crowding, thereby preventing local electric field distortion and improving insulation stability.
  • the insulating paper layer forming the first reinforcing insulating layer 2101 may be 90% or more of the number of insulating paper layers supported on the cable insulating layer 14A, and the insulating paper forming the first reinforcing insulating layer 2101 is half impregnated. Can be.
  • the half impregnation refers to insulating paper in which insulating paper is impregnated with insulating oil and then drained.
  • the intermediate junction box is an insulating paper which is not impregnated with insulating oil because it includes a weak mechanical property such as a softened portion formed at a portion where the metal sheath 22 and the metal shielding layer described later contact the cable. 1
  • a weak mechanical property such as a softened portion formed at a portion where the metal sheath 22 and the metal shielding layer described later contact the cable. 1
  • the insulation performance can be improved because In addition, by improving the dielectric strength of the first reinforcing insulating layer 2101, the height of the second reinforcing insulating layer 2102 is reduced and the size of the protective copper tube 240 is reduced to reduce the amount of insulating oil in the protective copper tube 240. Can be.
  • the junction box outer semiconducting layer 230 may be further formed.
  • the junction box outer semiconducting layer 230 is formed to surround the reinforcing insulating layer 210 and is energized with the outer semiconducting layer 16 to the metal sheath 22 of the cable.
  • the junction box outer semiconducting layer 230 is formed along the outer surface of the slope portion 2102B of the second reinforcement insulating layer 2102 and has a slope shape by itself. Continuous equipotential lines may be distributed according to the geometric shape of the junction box outer semiconducting layer 230 having a slope shape.
  • the junction box outer semiconducting layer 230 may have a lower volume resistance than the cable insulating layers 14A and 14B and the reinforcing insulating layer 210. That is, the electric field distribution may be controlled using the slope shape and the volume resistivity of the junction box external semiconducting layer 230.
  • the junction box outer semiconducting layer 230 may be formed by winding a semiconducting tape on the outer surface of the slope portion 2102B of the second reinforcement insulating layer, and may be energized with the outer semiconducting layer 16 of the cable.
  • the second reinforcement insulating layer 2102 may be formed to surround the straight portion 2102A.
  • the metal shielding layer which is energized with the metal sheath 22 of the cable 100A is restored on the reinforcing insulating layer 210, and the spacer 250 and the protective copper tube 240 are covered.
  • the metal shielding layer is formed to surround the slope portion 2102B and the straight portion 2102A and the junction box outer semiconducting layer 230 of the second reinforcement insulating layer.
  • the metal shielding layer formed to surround the slope portion 2102B of the second reinforcement insulating layer is preferably formed of a metal wire.
  • the metal wire may be a copper wire, a copper wire, a tin-plated copper wire, or the like, and may be formed by winding the metal wire to surround the slope portion 2102B or winding a braid made of the metal wire. Since the slope portion 2102B has a slope-shaped outer surface where the slope may not be constant, the junction outer semiconducting layer 230 and the metal shielding layer may be smoothly energized using the metal wire or braid. . In addition, since the insulating oil can penetrate between the metal wires, there is an advantage that the insulating oil impregnation to be described later is easy.
  • the intermediate junction box may include a metal shielding layer 250 formed to surround the straight portion 2102A of the second reinforcement insulating layer, and the metal shielding layer 250 may be formed of metal. It may be made of a tape to a metal plate. The workability can be improved by attaching a metal plate to the straight portion 2102B of the second reinforcement insulating layer having a relatively smooth outer surface or by winding a metal tape. However, the metal tape or the metal plate may be perforated to facilitate the impregnation of the insulating oil described later.
  • the spacer has a disk shape having a through hole therein, and may be made of a metal material such as aluminum, and formed on a straight portion of the second reinforcement insulating layer.
  • the spacer may be inserted outside the reinforcing insulating layer 210 through the through hole to maintain a gap between the copper tube 240 to be described later and the reinforcing insulating layer 210.
  • the spacer 250 may have a plurality of recesses 251 spaced apart from each other in the radial direction on the outer surface as shown in FIG. 5.
  • the insulating oil in the copper tube 240 passes through the recess 251.
  • the insulating oil injected into the copper tube 240 when the insulating oil is impregnated can be smoothly moved in the longitudinal direction of the intermediate junction box 200 through the recess 251.
  • metal wires may be wound and fixed on both sides of the spacer 250.
  • a metal shielding layer protection part 270 may be further formed between the metal shielding layer 260 and the spacer 250.
  • the metal shielding layer protection unit 270 is formed by winding an insulating paper on the metal shielding layer 260, and may prevent the metal shielding layer 260 from being damaged by the spacer 250.
  • a scratch occurs on the surface of the metal shielding layer 260 formed on the reinforcing insulating layer 210, or a load of an intermediate junction box is applied.
  • the metal shielding layer 260 may be pressed by the spacer 250 to generate an edge portion.
  • the metal shielding layer protection part 270 is formed between the spacer 250 and the metal shielding layer to prevent the metal shielding layer 260 from being damaged by the spacer 250, and to prevent surface damage such as edge generation and the like. This can prevent electric field concentration.
  • 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 intermediate connection system needs to ensure insulating performance by lubricating insulating oil in the intermediate junction box. Specifically, when the insulating oil is filled in the space between the reinforcing insulating layer and the protective copper tube, and particularly when the reinforcing insulating layer is formed by winding anti-oil immersion, the reinforcing insulating layer is impregnated with the insulating oil to improve the insulating performance. There is a need.
  • the protective copper tube 240 of the present invention may be provided with an insulating oil inlet pipe and an insulating oil discharge pipe.
  • the inlet pipe and the discharge pipe are formed on the outer surface of the protective copper tube 240 in opposite directions, and serve as a passage through which the insulating oil moves.
  • the insulating oil supplied into the protective copper tube through the inlet pipe is discharged to the outside through the upper discharge pipe while impregnating the reinforcing insulating layer 210 through the junction box outer semiconducting layer and the metal shielding layer.
  • the reinforcement insulating layer may be smoothly impregnated to improve the insulating performance.

Abstract

The present invention relates to: a direct current power cable joining system using a joint box for a power cable and improved in a surface electric field characteristic and an insulation performance; and a direct current power cable joint method.

Description

전력 케이블용 중간접속함을 이용한 직류 전력케이블 중간접속 시스템 및 직류 전력케이블 접속 방법DC power cable intermediate connection system and DC power cable connection method using power junction box
본 발명은 전력 케이블용 중간접속함을 이용한 직류 전력케이블 중간접속 시스템 및 직류 전력케이블 접속 방법에 관한 것이다. The present invention relates to a DC power cable intermediate connection system and a DC power cable connection method using an intermediate junction box for power cables.
일반적으로 전력케이블은 전력을 공급하는 도체를 이용하여 지중, 지상 또는 해저를 통하여 원하는 장소로 전력을 공급하도록 사용된다. 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.
상기 전력케이블은 수백m 또는 수십km 간격으로 중간접속함(Joint box)에 의해 접속이 이루어지며, 상기 전력케이블의 말단은 종단접속함(Termination connection box)에 의해 가공선과 접속이 이루어지게 된다. 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.
도 1을 참조하면, 상기 중간접속함에서 전력케이블을 연결하는 경우에 케이블의 절연층이 노출된 상태에서 도체(41A, 41B)를 먼저 연결하고 상기 절연층 표면에 절연지를 지권하여 보강절연층(50)을 형성하며, 이어서 외부반도전층(46), 금속시스(47) 등을 복원하게 된다.Referring to FIG. 1, when connecting a power cable in the intermediate junction box, the conductors 41A and 41B are first connected in a state where the insulation layer of the cable is exposed and the insulation paper is supported on the surface of the insulation layer. 50), and then the outer semiconducting layer 46, the metal sheath 47, and the like are restored.
상기 절연지를 지권하여 복원하는 경우, 케이블 절연층(44) 외경까지 제1 보강절연층(51)을 형성하고, 절연성능 보강을 위해 케이블 외경 이상에 제2 보강절연층(52)을 형성할 수 있다. 상기 제2 보강절연층(52) 형성 후에는 외부로부터 중간접속함 내부를 보호하는 보호동관(60)이 씌워진다. In the case of restoring the insulating paper, the first reinforcing insulating layer 51 may be formed up to the outer diameter of the cable insulating layer 44, and the second reinforcing insulating layer 52 may be formed above the outer diameter of the cable for reinforcing insulation performance. have. After the second reinforcement insulating layer 52 is formed, a protective copper tube 60 is provided to protect the inside of the intermediate junction box from the outside.
이와 같은 구조를 갖는 중간접속함은 상기 보호동관(60) 내부에 많은 양의 절연유가 주유된다. 케이블이 중간접속함에 의해 접속되는 케이블 접속 시스템이 작동하는 경우, 고전압에서 전류가 케이블에 흐르면서 케이블 접속 시스템이 진동할 수 있다. 상기 진동에 의한 중간접속함의 움직임을 막기 위해 상기 중간접속함을 파지하여 고정할 수 있다. 중간접속함을 충분히 파지하기 위해서는 중간접속함의 길이, 즉 보호동관의 길이가 확보되어야 하며, 보호동관의 길이가 길어짐에 따라 보호동관 내에 보강절연층이 형성되지 않는 공간(E)이 증가하게 되고, 이와 같은 빈 공간에는 절연유가 충진된다. 즉 중간접속함을 파지하지 않는 경우보다 중간접속함을 파지하는 경우에는 중간접속함을 안정적으로 파지하기 위해 보호동관(60)의 길이를 보다 길게 형성하여야 하며, 이에 따라 보호동관(60) 내에 공간이 증가하게 되어 보호동관(60) 내에 보다 많은 양의 절연유가 충진된다. The intermediate junction box having such a structure is filled with a large amount of insulating oil in the protective copper tube (60). When a cable connection system is operated in which the cable is connected by intermediate connection, the cable connection system may vibrate as current flows through the cable at high voltage. In order to prevent movement of the intermediate junction box caused by the vibration, the intermediate junction box may be gripped and fixed. In order to sufficiently hold the intermediate junction box, the length of the intermediate junction box, that is, the length of the protective copper tube, must be secured. As the length of the protective copper tube becomes longer, the space E in which the reinforcing insulation layer is not formed in the protective copper tube increases. This empty space is filled with insulating oil. That is, when the intermediate junction box is gripped than when the intermediate junction box is not held, the length of the protective copper tube 60 must be formed longer to stably hold the intermediate junction box. This increase increases the amount of insulating oil filled in the protective copper tube (60).
보호동관(60) 내의 절연유는 케이블 접속 시스템의 히팅(heating) 사이클에 따라 부피의 팽창 및 수축이 반복적으로 발생하며, 이에 따라 중간접속함의 내압의 변화를 야기시킬 수 있다. 상술한 바와 같이 중간접속함을 파지하기 위해 보호동관(60)의 길이를 길게 형상에 따라 보호동관(60) 내 절연유의 양이 증가하게 되면, 보호동관(60) 또는 연공부(보호동관과 케이블의 금속시스가 접합하는 부분)(61)가 지나친 내압상승으로 파괴되거나 반복적인 절연유의 팽창 및 수축에 의한 보호동관(60) 또는 연공부(61)의 피로파괴가 발생하여 절연유 유출 및 이에 따른 절연파괴가 되는 문제점이 있다. Insulating oil in the protective copper tube 60 repeatedly causes expansion and contraction of the volume according to the heating cycle of the cable connection system, thereby causing a change in the internal pressure of the intermediate junction box. As described above, if the amount of insulating oil in the protective copper tube 60 increases according to the shape of the length of the protective copper tube 60 to hold the intermediate junction box, the protective copper tube 60 or the soft portion (protective copper tube and cable Part of the metal sheath joined) is destroyed due to excessive pressure rise or fatigue breakdown of the protective copper tube 60 or the soft portion 61 occurs due to repeated expansion and contraction of the insulating oil, resulting in leakage of the insulating oil and the insulation thereof. There is a problem of being destroyed.
상기 보호동관(60) 내에 중입되는 절연유의 양을 줄이기 위하여 보강절연층(50)의 높이를 낮추고 보호동관(60)의 높이를 낮출 수 있다. 그러나, 보강절연층(50)의 높이를 낮게 형성한 경우에는 절연성능을 강화하기 위해 보강절연층(50)을 높게 형성하는 경우에 비하여 케이블의 절연층(44)과 중간접속함의 보강절연층 (50)사이의 계면의 길이를 보다 길게 형성하여야 하므로 전체적으로 중간접속함의 길이가 길어지는 문제점이 있다. In order to reduce the amount of insulating oil injected into the protective copper tube 60, the height of the reinforcing insulating layer 50 may be lowered and the height of the protective copper tube 60 may be lowered. However, when the height of the reinforcement insulating layer 50 is formed low, the reinforcement insulating layer of the intermediate junction box and the insulating layer 44 of the cable is higher than the case where the reinforcing insulating layer 50 is formed to increase the insulation performance. Since the length of the interface between the 50 must be formed longer, there is a problem in that the length of the intermediate junction as a whole.
본 발명의 목적은 중간접속함 내에 주입되는 절연유의 양을 최소화하면서 중간접속함의 길이를 컴팩트화할 수 있는 전력 케이블용 중간접속함을 이용한 직류 전력케이블 중간접속 시스템 및 직류 전력케이블 접속 방법을 제공하는 것이다.It is an object of the present invention to provide a DC power cable intermediate connection system and a DC power cable connection method using an intermediate junction box for a power cable capable of compacting the length of the intermediate junction box while minimizing the amount of insulating oil injected into the intermediate junction box. .
본 발명의 일 실시예에 따른 전력 케이블용 중간 접속함은, 도체, 내부반도전층, 케이블 절연층 및 외부반도전층을 구비하는 한 쌍의 직류 전력케이블과 상기 한 쌍의 직류 전력케이블을 서로 연결시키는 중간접속함을 포함하는 직류 전력케이블 중간접속 시스템에 있어서, 상기 한 쌍의 직류 전력케이블은 상기 도체, 내부반도전층, 케이블 절연층 및 외부반도전층이 순차적으로 노출된 각 단부가 서로 대향하도록 구비되고, 상기 중간접속함은, 상기 노출된 한 쌍의 도체를 전기적, 기계적으로 연결하는 도체 접속부; 상기 도체 접속부, 상기 노출된 내부반도전층 및 케이블 절연층을 둘러싸도록 절연지가 권취되어 상기 케이블 절연층 외경까지 형성되고, 길이방향에서의 양 단부에 경사면을 갖는 제1 보강절연층과, 상기 제1 보강절연층 및 상기 노출된 케이블 절연층을 둘러싸며 상기 케이블 길이방향으로의 폭이 일정한 직선부와 상기 직선부의 양단에 형성되며 상기 케이블 길이방향으로의 폭이 상기 케이블의 방사방향으로 감소하는 슬로프부를 구비한 제2 보강절연층을 포함하는 보강절연층; 및 상기 제2 보강절연층의 슬로프부의 외측면을 따라 형성되어 그 자체로 슬로프 형상을 가지며, 반도전성 재질로 이루어진 접속함 외부반도전층을 구비하며, 상기 제1 보강절연층과 상기 케이블 절연층 사이의 계면은 단일 경사면으로 이루어지고, 상기 제2 보강절연층은 상기 제1 보강절연층 상에 적층되는 복수 개의 절연지층으로 이루어지며, 상기 절연지층 각각은 세폭지가 지권되어 형성되는 적어도 하나의 세폭지 권취부 및 상기 세폭지 보다 폭이 더 넓은 광폭지가 지권되어 형성되는 광폭지 권취부로 이루어지고, 상기 제1 보강절연층에 권취된 절연지는 그 폭이 상기 제2 보강절연층의 세폭지 권취부를 형성하는 절연지의 폭보다는 크고, 보강절연층의 광폭지 권취부를 형성하는 절연지의 폭보다는 작을 수 있다.An intermediate junction box for a power cable according to an embodiment of the present invention includes a pair of DC power cables having a conductor, an inner semiconducting layer, a cable insulation layer, and an outer semiconducting layer and connecting the pair of DC power cables to each other. In a DC power cable intermediate connection system comprising an intermediate junction, the pair of DC power cables are provided so that each end of the conductor, the inner semiconducting layer, the cable insulation layer and the outer semiconducting layer are sequentially exposed to each other. The intermediate junction box may include: a conductor connection part for electrically and mechanically connecting the exposed pair of conductors; A first reinforcing insulating layer wound around the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer, and formed up to an outer diameter of the cable insulating layer, and having a sloped surface at both ends in the longitudinal direction, and the first reinforcing layer A straight line portion surrounding the exposed insulation layer and the exposed cable insulation layer and having a constant width in the longitudinal direction of the cable and a slope portion having a width in the longitudinal direction of the cable reduced in the radial direction of the cable are formed at both ends. A reinforcing insulating layer including a second reinforcing insulating layer provided; And a junction box outer semiconducting layer formed along the outer surface of the slope portion of the second reinforcing insulating layer and having a slope shape by itself, and made of a semiconductive material, between the first reinforcing insulating layer and the cable insulating layer. The interface of is made of a single inclined surface, the second reinforcement insulating layer is composed of a plurality of insulating paper layer laminated on the first reinforcing insulating layer, each of the insulating paper layer is formed of at least one narrow paper is supported by the narrow paper And a wide paper winding portion formed by winding a wide paper wider than the narrow paper, and the insulating paper wound on the first reinforcing insulating layer forms a narrow paper winding portion of the second reinforcing insulating layer. It may be larger than the width of the insulating paper, and may be smaller than the width of the insulating paper forming the wide paper winding of the reinforcing insulating layer.
본 발명에 있어서, 상기 제1 보강절연층에 지권된 절연지 층수는 상기 케이블 절연층에 지권된 절연지 층수의 80% 이상일 수 있다.In the present invention, the number of insulating paper layers supported on the first reinforcement insulating layer may be 80% or more of the number of insulating paper layers supported on the cable insulating layer.
본 발명에 있어서, 상기 제2 보강절연층에서의 어느 한 절연지층의 세폭지 권취부는 상기 절연지층에 인접한 절연지층의 세폭지 권취부와 소정의 거리만큼 이격되어 배치될 수 있다. In the present invention, the narrow paper winding of one of the insulating paper layers in the second reinforcing insulating layer may be spaced apart from the narrow paper winding of the insulating paper layer adjacent to the insulating paper layer by a predetermined distance.
본 발명에 있어서, 상기 제2 보강절연층에서의 어느 한 절연지층의 세폭지 권취부는 상기 절연지층 상에 접하여 위치하거나 아래 접하여 위치하는 다른 절연지층의 세폭지 권취부와 상하 방향에서 서로 중첩되지 않을 수 있다. In the present invention, the narrow paper winding portion of one insulating paper layer in the second reinforcing insulating layer does not overlap with the narrow paper winding portion of another insulating paper layer positioned on or in contact with the insulating paper layer in the vertical direction. Can be.
본 발명에 있어서, 상기 제2 보강절연층에서의 어느 한 절연지층의 세폭지 권취부에서 상기 절연지층 상에 접하여 위치하거나 아래 접하여 위치하는 다른 절연지층의 세폭지 권취부까지의 이격된 거리는, 상기 절연지층에 접하는 절연지층 내에서 서로 인접한 광폭지 권취부들이 접하여 형성되는 맞대기부와 상기 절연지층의 세폭지 권취부 사이의 최단 거리보다 크거나 같을 수 있다. In the present invention, the distance from the narrow paper winding portion of the insulating paper layer in the second reinforcing insulating layer to the narrow paper winding portion of the other insulating paper layer which is located on or in contact with the insulating paper layer, It may be greater than or equal to the shortest distance between the butt portion formed by contacting the wide paper winding portions adjacent to each other in the insulating paper layer in contact with the insulating paper layer and the narrow paper winding portion of the insulating paper layer.
본 발명에 있어서, 상기 세폭지 권취부는 상기 슬로프부에는 위치하지 않고 상기 직선부에 위치할 수 있다. In the present invention, the narrow paper winding portion may be located on the straight portion without being located on the slope portion.
본 발명에 있어서, 상기 슬로프부는 상기 광폭지 권취부로 이루어질 수 있다. In the present invention, the slope portion may be made of the wide paper winding portion.
본 발명에 있어서, 상기 중간접속함은, 상기 접속함 외부반도전층 상에 형성되는 금속차폐층; 상기 보강절연층 및 상기 전력 케이블의 일부를 감싸며 그 내부에 절연유를 포함하는 동관; 및 상기 동관과 상기 금속차폐층 사이의 간격을 유지시키는 스페이서; 를 포함할 수 있다. In the present invention, the intermediate junction box, the metal shielding layer formed on the junction box outer semiconducting layer; A copper tube surrounding the reinforcement insulating layer and a part of the power cable and including insulating oil therein; And a spacer for maintaining a gap between the copper tube and the metal shielding layer. It may include.
본 발명에 있어서, 상기 도체접속부는, 사선으로 절단되어 단부가 서로 대향하도록 구비된 한 쌍의 도체; 및 상기 도체의 단부 사이에 형성된 필러금속을 포함할 수 있다. In the present invention, the conductor connection portion is a pair of conductors are cut diagonally and the ends are provided facing each other; And it may include a filler metal formed between the end of the conductor.
본 발명에 있어서, 상기 케이블에서 노출되어 단부가 서로 대향하도록 구비된 한 쌍의 도체; 및 상기 한 쌍의 도체 단부를 둘러싸는 도체 압착슬리브;를 구비하며, 상기 도체 압착슬리브는 외경이 상기 도체의 외경이 동일할 수 있다. In the present invention, a pair of conductors exposed from the cable and the ends are provided facing each other; And a conductor crimp sleeve surrounding the pair of conductor ends, wherein the conductor crimp sleeve may have the same outer diameter as the outer diameter of the conductor.
본 발명의 일 실시예에 따른 직류 전력케이블 접속 방법은, 도체, 내부반도전층, 케이블 절연층 및 외부반도전층을 구비하며, 상기 도체, 내부반도전층, 케이블 절연층 및 외부반도전층이 순차적으로 노출된 각 단부가 대향하도록 구비된 한 쌍의 직류 전력 케이블을 서로 접속하는 방법에 있어서, 상기 노출된 한 쌍의 도체를 서로 전기적, 기계적으로 연결하여 도체 접속부를 형성하는 단계; 상기 도체 접속부, 상기 노출된 내부반도전층 및 케이블 절연층을 둘러싸도록 절연지를 상기 케이블 절연층 외경까지 권취하여 제1 보강절연층을 형성하는 단계; 상기 제1 보강절연층 및 상기 노출된 케이블 절연층을 둘러싸도록 절연지를 권취하여 제2 보강절연층을 형성하는 단계; 및 상기 제2 보강절연층의 외면을 둘러싸는 접속함 외부반도전층을 형성하는 단계;를 구비하며, 상기 제2 보강절연층을 형성하는 단계는 상기 제1 보강절연층 상에 세폭지 권취부 및 상기 세폭지 권취부를 이루는 절연지보다 폭이 큰 절연지로 이루어진 광폭지 권취부를 포함하는 절연지층을 복수개 적층하는 단계를 포함하고, 상기 제1 보강절연층을 형성하는 단계는, 상기 노출된 케이블 절연층의 단부 형상에 대응하도록 상기 제1 보강절연층 단부에 단일 경사면을 형성하는 단계와, 상기 세폭지 권취부의 절연지보다 폭이 크고 보다 크고, 광폭지 권취부의 절연지보다 폭이 작은 절연지를 권취하는 단계를 포함할 수 있다. The DC power cable connecting method according to an embodiment of the present invention includes a conductor, an inner semiconducting layer, a cable insulation layer, and an outer semiconducting layer, and the conductor, the inner semiconducting layer, the cable insulation layer, and the outer semiconducting layer are sequentially exposed. A method of connecting a pair of DC power cables provided so that the respective ends thereof face each other, the method comprising: electrically and mechanically connecting the exposed pair of conductors to each other to form a conductor connection; Forming a first reinforcing insulating layer by winding insulating paper to the outer diameter of the cable insulating layer so as to surround the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer; Forming a second reinforcing insulating layer by winding insulating paper to surround the first reinforcing insulating layer and the exposed cable insulating layer; And forming a junction box outer semiconducting layer surrounding the outer surface of the second reinforcing insulating layer, wherein the forming of the second reinforcing insulating layer comprises: a narrow paper winding part on the first reinforcing insulating layer; Stacking a plurality of insulating paper layers including a wide paper winding portion formed of an insulating paper having a width larger than that of the narrow paper winding portion, wherein the forming of the first reinforcing insulating layer includes: Forming a single inclined surface at the end of the first reinforcing insulating layer so as to correspond to an end shape; and winding an insulating paper having a width larger and larger than that of the narrow paper winding portion and having a width smaller than that of the wide paper winding portion. It may include.
본 발명에 있어서, 상기 제1 보강절연층을 형성하는 단계는, 상기 절연지는 반유침지이며, 상기 케이블 절연층에 권취된 절연지의 층수의 80% 이상 상기 반유침지를 권취할 수 있다. In the present invention, the forming of the first reinforcing insulating layer, the insulating paper is semi-immersion immersion, it can be wound at least 80% of the number of layers of the insulating paper wound on the cable insulation layer.
본 발명에 있어서, 상기 제2 보강절연층을 형성하는 단계는, 상기 제2 보강절연층의 어느 한 절연지층의 세폭지 권취부를 상기 절연지층에 인접한 절연지층의 세폭지 권취부와 소정의 거리만큼 이격시켜 배치할 수 있다. In the present invention, the forming of the second reinforcement insulating layer may include: forming a narrow paper winding portion of the insulating paper layer of the second reinforcing insulating layer by a predetermined distance from the narrow paper winding portion of the insulating paper layer adjacent to the insulating paper layer. Can be spaced apart.
본 발명에 있어서, 상기 제2 보강절연층을 형성하는 단계는, 상기 제2 보강절연층의 어느 한 절연지층의 세폭지 권취부를 상기 절연지층에 접하여 위치하는 다른 절연지층의 세폭지 권취부와 서로 중첩되지 않도록 배치할 수 있다. In the present invention, the forming of the second reinforcing insulating layer may include forming a narrow paper winding portion of one of the insulating paper layers of the second reinforcing insulating layer and the narrow paper winding portion of the other insulating paper layer positioned in contact with the insulating paper layer. It can be arranged so that they do not overlap.
본 발명에 있어서, 상기 제2 보강절연층을 형성하는 단계는, 상기 제2 보강절연층의 어느 한 절연지층의 세폭지 권취부를 상기 절연지층 상에 접하여 위치하거나 아래 접하여 위치하는 다른 절연지층의 세폭지 권취부까지의 이격된 거리는, 상기 절연지층에 접하는 절연지층 내에서 서로 인접한 광폭지 권취부들이 접하여 형성되는 맞대기부와 상기 절연지층의 세폭지 권취부 사이의 최단 거리보다 크거나 같도록 배치할 수 있다. In the present invention, the forming of the second reinforcement insulating layer may include: forming a third paper winding portion of one of the insulating paper layers of the second reinforcing insulating layer on the insulating paper layer or below the other insulating paper layer. The spaced distance to the winding paper winding portion may be arranged to be greater than or equal to the shortest distance between the butt portion formed by the adjacent wide paper winding portions in contact with the insulating paper layer and the narrow paper winding portion of the insulating paper layer. Can be.
본 발명에 있어서, 상기 제2 보강절연층을 형성하는 단계는, 상기 슬로프부에는 상기 세폭지 권취부를 배치하지 않을 수 있다. In the present invention, the forming of the second reinforcement insulating layer may not include the narrow paper winding part on the slope part.
본 발명에 있어서, 상기 제2 보강절연층을 형성하는 단계는, 상기 슬로프부에 상기 광폭지 권취부만을 배치할 수 있다. In the present invention, the forming of the second reinforcement insulating layer may include disposing only the wide winding portion in the slope portion.
본 발명에 있어서, 상기 접속함 외부반도전층을 둘러싸도록 금속차폐층을 형성하는 단계; 상기 제2 보강절연층의 직선부의 일부를 둘러싸도록 스페이서를 형성하는 단계; 상기 보강절연층 및 상기 전력 케이블의 일부를 감싸는 동관을 설치하는 단계; 및 상기 동관에 절연유를 주입하고 가압하여 상기 보강절연층의 절연지를 함침시키는 단계를 포함할 수 있다. Forming a metal shielding layer to surround the junction box outer semiconducting layer; Forming a spacer to surround a portion of the straight portion of the second reinforcement insulating layer; Installing a copper tube surrounding the reinforcement insulating layer and a part of the power cable; And impregnating and insulating the insulating paper of the reinforcing insulating layer by injecting and pressing the insulating oil into the copper tube.
본 발명에 있어서, 상기 금속차폐층을 형성하는 단계는, 금속선재가 상기 제2 보강절연층의 슬로프부를 둘러싸도록 권취하며, 천공된 금속판이 상기 제2 보강절연층의 직선부를 둘러싸도록 형성하는 단계를 포함할 수 있다. In the present invention, the forming of the metal shielding layer may include forming a metal wire to surround the slope of the second reinforcing insulating layer, and forming the perforated metal plate to surround the straight portion of the second reinforcing insulating layer. It may include.
본 발명에 있어서, 상기 금속차폐층을 형성하는 단계는, 상기 천공된 금속판이 상기 직선부를 둘러싸도록 종첨하고 접합할 수 있다. In the present invention, the forming of the metal shielding layer may be terminated and joined so that the perforated metal plate surrounds the straight portion.
본 발명에 있어서, 상기 스페이서를 형성하는 단계는, 내부에 상기 제2 보강절연층의 외경보다 더 큰 내경을 갖는 관통공과, 그 외측부에는 상기 관통공을 향하는 오목부를 포함하며, 상기 오목부를 통해 상기 동관 내의 상기 절연유가 상기 중간접속함의 길이 방향으로 유동할 수 있는 것을 특징으로 하는 스페이서를 상기 제2 보강절연층의 직선부에 배치할 수 있다. In the present invention, the forming of the spacer may include a through hole having an inner diameter larger than an outer diameter of the second reinforcement insulating layer therein, and a recessed portion facing the through hole at an outer portion thereof, The insulating oil in the copper pipe can flow in the longitudinal direction of the intermediate junction can be arranged in a straight portion of the second reinforcing insulating layer.
본 발명에 있어서, 상기 도체 접속부를 형성하는 단계는, 상기 케이블에서 노출되어 단부가 서로 대향하도록 구비된 한 쌍의 도체 단부 사이에 필러금속을 충진할 수 있다. In the present invention, the forming of the conductor connection may include filling filler metal between a pair of conductor ends exposed from the cable so that the ends thereof face each other.
본 발명에 있어서, 상기 도체 접속부를 형성하는 단계는, 상기 케이블에서 노출되어 단부가 서로 대향하도록 구비된 한 쌍의 도체의 각 단부를 둘러싸도록 도체 압착슬리브 배치하고, 상기 도체압착슬리브의 외면을 압착하며, 상기 도체압착슬리브의 외경과 상기 도체의 외경이 동일하도록 형성할 수 있다. In the present invention, the step of forming the conductor connecting portion, the conductor crimp sleeve is disposed so as to surround each end of the pair of conductors exposed from the cable so that the ends are opposed to each other, and crimp the outer surface of the conductor crimp sleeve The outer diameter of the conductor crimp sleeve may be the same as the outer diameter of the conductor.
본 발명의 일 실시예에 따르면, 제1 보강절연층의 절연내력을 향상시킴으로써 절연성능을 확보하여, 제2 보강 절연층의 높이를 낮추고 동관의 크기를 축소시켜 보호동관 내 절연유의 양을 감소시킬 수 있다. According to an embodiment of the present invention, by improving the insulation strength of the first reinforcement insulating layer to ensure the insulating performance, the height of the second reinforcing insulating layer to reduce the size of the copper tube to reduce the amount of insulating oil in the protective copper tube Can be.
도 1은 종래의 중간접속함에 의해 접속된 케이블을 개략적으로 나타내는 단면도이다. 1 is a cross-sectional view schematically showing a cable connected by a conventional intermediate junction box.
도 2는 전력케이블의 내부 구성을 도시한 사시도이다.2 is a perspective view showing an internal configuration of a power cable.
도 3은 중간접속함에 의해 접속된 케이블을 개략적으로 나타내는 부분 절개도이다.3 is a partial cutaway view schematically showing a cable connected by an intermediate connection.
도 4는 도 3에 도시된 중간접속함의 제1 보강절연층과 제2 보강절연층을 보다 상세하게 도시한 단면도이다.4 is a cross-sectional view illustrating in detail the first reinforcing insulating layer and the second reinforcing insulating layer of the intermediate junction box shown in FIG. 3.
도 5는 도 3에 도시된 중간접속함을 개략적으로 나타내는 횡단면도이다.FIG. 5 is a cross-sectional view schematically illustrating the intermediate junction box shown in FIG. 3.
이하, 첨부된 도면들을 참조하여 본 발명의 바람직한 실시예들을 상세히 설명하기로 한다. 그러나, 본 발명은 여기서 설명된 실시예들에 한정되지 않고 다른 형태로 구체화될 수도 있다. 오히려, 여기서 소개되는 실시예들은 개시된 내용이 철저하고 완전해질 수 있도록, 그리고 당업자에게 본 발명의 사상이 충분히 전달될 수 있도록 하기 위해 제공되는 것이다. 명세서 전체에 걸쳐서 동일한 참조번호들은 동일한 구성요소들을 나타낸다.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.
일반적으로 절연유 함침 케이블은 수백m 내지는 수km 간격으로 중간접속함에 의해 접속이 이루어지며, 절연유 함침 케이블의 말단은 종단접속함에 의해 가공선과 접속이 이루어지게 된다. 이하에서는 먼저 절연유 함침 전력케이블의 구성에 대해서 살펴보고, 이어서 접속함의 연결과정을 살펴보기로 한다.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.
도 2는 초고압 직류 전력케이블의 내부 구성을 도시한 일부 절개 사시도이다.2 is a partially cutaway perspective view illustrating an internal configuration of an ultra high voltage direct current power cable.
도 2를 참조하면, 전력케이블(100)은 도체(11), 내부반도전층(12), 케이블 절연층(14), 외부반도전층(16)을 포함하여, 도체(11)를 따라 케이블 길이 방향으로만 전력을 전송하고, 케이블 반경 방향으로는 전류가 누설되지 않도록 하는 케이블 코어부(10)를 구비한다.Referring to FIG. 2, the power cable 100 includes a conductor 11, an inner semiconducting layer 12, a cable insulation layer 14, and an outer semiconducting layer 16, along a cable length direction along the conductor 11. It is provided with a cable core portion 10 that transmits power only in such a way that a current does not leak in the cable radial direction.
상기 도체(11)는 전력을 전송하기 위해 전류가 흐르는 통로 역할을 하며, 전력 손실을 최소화할 수 있도록 도전율이 우수하고 케이블 제조 및 사용에 적절한 강도와 유연성을 가진 소재, 예를 들어 구리 또는 알루미늄 등으로 이루어질 수 있다.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.
상기 도체(11)는 도 2에 도시된 바와 같이, 원형의 중심소선(11a)과 상기 원형 중심소선(11a)을 감싸도록 연선된 평각소선(11b)으로 이루어진 평각소선층(11C)을 구비하며 전체적으로 원형의 단면을 가지는 평각도체일 수 있으며, 다른 예로서 복수개의 원형소선을 연선하여 원형으로 압축한 원형 압축도체일 수 있다. 상기 평각도체는 원형 압축도체에 비하여 점적율이 상대적으로 높아 케이블 외경을 축소할 수 있는 장점이 있다.As shown in FIG. 2, 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 surround 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.
상기 도체(11)는 복수개의 소선이 연선되어 형성되므로 그 표면이 평활하지 않아 전계가 불균일할 수 있으며, 부분적으로 코로나 방전이 일어나기 쉽다. 또한, 도체(11) 표면과 후술하는 케이블 절연층(14) 사이에 공극이 생기게 되면 절연성능이 저하될 수 있다.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 cable insulation layer 14 described later, the insulation performance may be reduced.
상기와 같은 문제점을 해결하기 위하여 상기 도체(11) 외부에는 내부반도전층(12)이 형성될 수 있다. 상기 내부반도전층(12)은 절연성 물질에 카본블랙, 카본 나노튜브, 카본나노플레이트, 그라파이트 등의 도전성 입자가 첨가되어 반도전성을 가질 수 있다.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.
상기 내부반도전층(12)은 상기 도체(11)와 후술하는 케이블 절연층(14) 사이에서 급격한 전계변화가 발생하는 것을 방지하여 절연성능을 안정화하는 기능을 수행한다. 또한, 도체면의 불균일한 전하분포를 억제함으로써 전계를 균일하게 하고, 도체(11)와 케이블 절연층(14) 사이에 간격이 형성되는 것을 방지하여 코로나 방전, 절연파괴 등을 억제하는 역할도 하게 된다.The inner semiconducting layer 12 functions to stabilize the insulation performance by preventing a sudden electric field change between the conductor 11 and the cable insulation layer 14 to be 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 cable insulation layer 14 is prevented from forming so as to suppress corona discharge and insulation breakdown. do.
상기 케이블 절연층(14)은 상기 내부반도전층(12)의 바깥쪽에 구비되어 도체(11)를 따라 흐르는 전류가 외부로 누설되지 않도록 외부와 전기적으로 절연시켜 준다.The cable insulation layer 14 is provided outside the inner semiconducting layer 12 to electrically insulate the outside from the current flowing along the conductor 11 so as not to leak to the outside.
상기 케이블 절연층(14)은 절연유에 함침된 절연지로 형성될 수 있다. 즉, 상기 케이블 절연층(14)은 상기 내부반도전층(12)을 둘러싸도록 절연지가 다층으로 권취되고, 상기 케이블 코어부가 형성된 후 절연유에 함침시킴으로써 형성될 수 있다. 이와 같이 절연유가 절연지에 흡수되는바, 케이블 절연층(14)의 절연 특성이 향상될 수 있다.The cable insulating layer 14 may be formed of insulating paper impregnated with insulating oil. That is, the cable insulating layer 14 may be formed by winding insulating paper in multiple layers so as to surround the internal semiconducting layer 12, and then impregnating the cable core with an insulating oil. As the insulating oil is absorbed into the insulating paper as described above, the insulating property of the cable insulating layer 14 may be improved.
상기 절연유는 상기 절연지 내부의 공극 및 상기 절연지를 권취하여 형성된 층간의 틈에 충진되어 절연특성을 향상시키며, 케이블의 굽힘시 상기 절연지 간의 마찰력을 저감시켜 케이블의 굴곡 특성을 향상시킨다. 상기 절연유는 그 종류가 특별히 제한되지는 않지만, 상기 도체(11)를 구성하는 구리 또는 알루미늄과 접촉하여 열에 의해 산화되지 않아야 하며, 상기 절연지를 용이하게 함침할 수 있도록 함침온도, 예를 들어 100℃에서는 충분히 낮은 점도를 가지며, 60℃에서의 동점도가 10~500 센티스토크(centistoke)인 중점도 절연유 또는 60℃에서의 동점도가 500 센티스토크 이상인 고점도의 절연유를 사용하는 것이 바람직하다.The insulating oil is filled in the gaps 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.
상대적으로 점도가 낮은 저점도 절연유를 사용하는 경우, 절연지가 절연유에 함침된 상태를 유지시키고, 절연유의 유동에 의해 케이블 절연층에 공극이 생기는 것을 방지하기 위해 급유설비 등을 사용하여 절연유를 가압할 필요가 있다. 하지만, 중점도 또는 고점도 절연유를 사용하는 경우에는 절연유의 유동이 적기 때문에 절연유를 가압하기 위한 급유설비가 필요 없거나, 필요한 급유설비의 수를 줄일 수 있어 케이블 연장길이를 길게 할 수 있는 장점이 있다. 예를 들어, 상기 절연유는 나프텐계 절연유, 폴리스틸렌계 절연유, 광유, 알킬 벤젠이나 폴리부텐계 합성유, 중질 알켈레이트 등으로 이루어진 그룹으로부터 선택된 1종 이상의 절연유를 사용할 수 있다.When using a low viscosity insulating oil having a relatively low viscosity, pressurizing 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 cable insulating layer due to the flow of the insulating oil. There is a need. However, in the case of using a medium viscosity or high viscosity insulating oil, since the flow of the insulating oil is small, it is not necessary to supply the oil supply equipment for pressurizing the insulating oil, or the number of necessary oil supply equipment can be reduced, thereby extending the cable 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.
상기 절연지는 크래프트 펄프(Kraft pulp)를 원료로 하여 펄프 중의 유기 전해질을 제거한 크래프트지(Kraft paper) 또는 플라스틱 필름의 일면 또는 양면에 크래프트지를 접착한 복합절연지일 수 있다. 상기 플라스틱 필름은 그 일면 또는 양면에 접착되는 크래프트지 보다 큰 저항률을 가져 함침공정 또는 케이블 작동시 절연유의 유동에 따라 크래프트지에 기포가 생성되더라도 그 기포에 분담되는 전압을 완화할 수 있으며, 폴리에틸렌(Polyethylen), 폴리프로필렌(Polypropylene), 폴리부틸렌(Polybutylen) 등의 폴리올레핀계 수지나 테트라플루오로에틸렌-헥사플루오로폴리프로필렌(Tetrafluoroethylene-Hexafluoropropylene) 공중합체, 에틸렌-테트라플루오로에틸렌(Ethylen-tetrafluoroethylene) 공중합체 등의 불소 수지로 이루어질 수 있고, 바람직하게는 내열성이 우수한 폴리프로필렌 단독중합체 수지로 이루어질 수 있다.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.
구체적으로, 상기 케이블 절연층(14)은 크래프트지만을 권취하고, 절연유에 함침시켜 형성될 수 있다. 이 경우 상기 절연유가 케이블 하중방향으로 절연유가 유동하여 공극이 발생할 수 있다. 반면, 복합 절연지를 권취하고, 절연유에 함침시켜 상기 케이블 절연층(14)을 형성하는 경우, 상기 폴리프로필렌 수지 등과 같은 열가소성 수지는 절연유에 함침되지 않으며, 케이블 제조시의 함침 온도 또는 케이블 작동시의 작동 온도에 따라 열팽창을 하게 된다. 열가소성 수지가 열팽창을 하게 되면 이에 적층된 크래프트지에 면압을 가하게 되어 절연유의 이동 통로를 협소하게 하므로 중력에 따른 절연유 유동 또는 온도에 따른 절연유의 수축/팽창에 유동을 억제할 수 있는 효과가 있다. 뿐만 아니라, 상기 복합 절연지는 크래프트지 보다 절연내력이 높아 케이블 외경을 축소할 수 있는 장점이 있다.Specifically, the cable insulation layer 14 may be formed by winding only the kraft and impregnating the insulation 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 cable 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 production or at the time of cable operation Thermal expansion occurs depending on the operating 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.
한편, 상기 전력 케이블을 통전시키는 경우, 전류가 흐르는 통로 역할을 하는 도체에 열이 발생하며, 케이블 반경방향으로 내측에서 외측을 향해 온도가 점차 낮아지게 되어 상기 케이블 절연층(14)에서도 온도 차이가 발생한다. 따라서, 상기 도체 직상구간에 속하는 케이블 절연층, 즉 내부반도전층(12) 상에 형성되는 케이블 절연층의 절연유는 점도가 낮아지고 열팽창을 하여 바깥방향으로 이동하게 되며, 케이블 온도 하강시에는 이동한 절연유의 점도가 높아지고 원래대로 되돌아가지 않게 되어 도체 직상 구간의 케이블 절연층 부분에 공극이 발생하게 될 수 있다.On the other hand, when the power cable is energized, heat is generated in the conductor that serves 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 the temperature difference also occurs in the cable insulation layer 14. Occurs. Therefore, the insulating oil of the cable insulating layer, ie, the cable insulating layer formed on the inner semiconducting layer 12, which belongs to the upper section of the conductor is lowered in viscosity and thermally expands to move outward, and moves when the cable temperature falls. As the viscosity of the insulating oil becomes high and does not return to the original state, voids may occur in a portion of the cable insulating layer in the section immediately above the conductor.
또한, 상기 온도 차이에 따라 점차 전계가 역전되어 작용하는 전계가 점차 높아지는 금속시스 직하구간에 속하는 케이블 절연층, 즉 외부반도전층(16) 방향으로 형성되는 케이블 절연층에는 높은 전계가 작용하게 된다. 상기 도체 직상구간 및 금속시스 직하구간은 공극이 발생할 가능성이 높고, 케이블 내부의 온도 변화에 따라 고전계가 작용하는 영역으로 부분방전, 절연파괴 등의 기점이 되는 절연 취약부로 작용할 수 있다.In addition, a high electric field acts on the cable insulation layer formed in the direction of the outer semiconducting layer 16, which belongs to the cable insulation layer directly below the metal sheath, in which the electric field is gradually reversed according to the temperature difference and the electric field gradually increases. 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.
상술한 문제점을 해결하기 위해, 상기 케이블 절연층(14) 중 상기 절연 취약부를 포함하는 영역에는 절연지로 크래프트지만을 사용할 수 있다. 즉, 상기 케이블 절연층(14)을 상기 내부반도전층(12)에서 후술하는 외부반도전층(16) 방향으로 제1 케이블 절연층, 제2 케이블 절연층 및 제3 케이블 절연층으로 구분하여 제1 케이블 절연층 및/또는 제3 케이블 절연층에는 크래프트지만을 사용하며, 제2 케이블 절연층에는 상기 복합 절연지를 사용할 수 있다.In order to solve the above problems, only the kraft may be used as the insulating paper in the area including the weak insulation of the cable insulating layer (14). That is, the cable insulation layer 14 is divided into a first cable insulation layer, a second cable insulation layer, and a third cable insulation layer in a direction from the inner semiconducting layer 12 to the outer semiconducting layer 16 described later. Only kraft may be used for the cable insulation layer and / or the third cable insulation layer, and the composite insulation may be used for the second cable insulation layer.
이 경우, 복합절연지가 권취된 제2 케이블 절연층과 크래프트지가 권취된 제1 케이블 절연층 및/또는 제3 케이블 절연층 간에 저항률 차이가 발생하며, 저항률이 낮은 크래프트지가 권취된 상기 케이블 절연층(14)의 제1 케이블 절연층 및/또는 제3 케이블 절연층은 저항률이 상대적으로 낮아 상기 절연 취약부에 분담되는 전계를 완화하는 작용을 한다. 구체적으로, 저항률에 따라 전계가 분포되는 직류 케이블의 저항성 전계분포 특성상 저항률이 높은 복합 절연지가 권취된 상기 제2 케이블 절연층에 높은 전계가 작용하며, 상기 제1 케이블 절연층 및/또는 제3 케이블 절연층에 포함된 도체 직상구간 및/또는 금속시스 직하구간에 상대적으로 낮은 전계가 작용하므로 절연 취약부에 작용하는 전계가 완화되어 절연 성능을 안정화할 수 있다.In this case, a resistivity difference occurs between the second cable insulation layer wound with the composite insulation paper and the first cable insulation layer and / or the third cable insulation layer wound with the kraft paper, and the cable insulation layer wound with the kraft paper having a low resistivity ( The first cable insulation layer and / or the third cable insulation layer of 14) has a relatively low resistivity, and serves to alleviate an electric field distributed to the weak insulation portion. Specifically, a high electric field acts on the second cable 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 cable insulating layer and / or the third cable Since a relatively low electric field acts on the section immediately above the conductor and / or the section directly below the metal sheath included in the insulating layer, the electric field acting on the weak part of the insulation can be alleviated to stabilize the insulation performance.
또한, 상기 케이블 절연층(14)은 제3 케이블 절연층을 제1 케이블 절연층 보다 두껍게 형성할 수 있다. 상기 케이블 절연층(14)의 외부에 후술하는 금속시스(22)를 형성하거나, 케이블 코어부가 내측부터 순차적으로 노출된 두 개의 전력 케이블을 접속한 후 금속시스(22)을 복원하는 경우 등에 있어서 가해지는 열이 상기 케이블 절연층(14)의 제2 케이블 절연층에 인가되어 상기 플라스틱 필름의 변형이 발생할 수 있기 때문에 상기 제1 케이블 절연층보다 제2 케이블 절연층을 두껍게 형성하여 제2 케이블 절연층의 플라스틱 필름을 열로부터 보호하는 것이 바람직하다. 이 경우, 상기 제1 케이블 절연층의 두께는 전력 케이블에 요구되는 임펄스 서지 전압 등을 고려하여 선정할 수 있다.In addition, the cable insulation layer 14 may form a third cable insulation layer thicker than the first cable insulation layer. The metal sheath 22, which will be described later, is formed on the outside of the cable insulation 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 losing heat is applied to the second cable insulating layer of the cable insulating layer 14 to cause deformation of the plastic film, the second cable insulating layer is formed by forming a second cable insulating layer thicker than the first cable insulating layer. It is desirable to protect the plastic film from heat. In this case, the thickness of the first cable insulation layer may be selected in consideration of the impulse surge voltage required for the power cable.
상기 케이블 절연층(14)의 외부에는 외부반도전층(16)이 구비될 수 있다. 상기 외부반도전층(16)은 내부반도전층과 같이 절연성 물질에 도전성 입자, 예를 들면 카본블랙, 카본나뉴튜브, 카본나노플레이트, 그라파이트 등이 첨가되어 반도전성을 가지는 물질로 형성되어, 상기 케이블 절연층(14)과 후술하는 금속시스(22) 사이의 불균일한 전하 분포를 억제하여 절연 성능을 안정화한다. 또한, 상기 외부반도전층(16)은 케이블에 있어서 케이블 절연층(14)의 표면을 평활하게 하여 전계집중을 완화시켜 코로나 방전을 방지하며, 상기 케이블 절연층(14)을 물리적으로 보호하는 기능도 수행할 수 있다. 또한, 상기 외부반도전층(16)은 금속화지를 추가로 구비할 수 있다. 상기 금속화지는 크래프트지에 알루미늄 박막을 적층하여 형성할 수 있으며, 상기 케이블 절연층(14)의 절연유 함침이 용이하도록 복수개의 천공이 존재할 수 있다.An external semiconducting layer 16 may be provided outside the cable insulation 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. The nonuniform charge distribution between the layer 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 cable insulating layer 14 in the cable to mitigate electric field concentration to prevent corona discharge, and also physically protects the cable insulating layer 14. Can be done. In addition, the outer semiconducting layer 16 may further include a metallized paper. The metallized paper may be formed by stacking a thin aluminum film on kraft paper, and a plurality of perforations may exist to facilitate the impregnation of the insulating film of the cable insulating layer 14.
상기 케이블 코어부(10)는 케이블에 수분이 침투하는 것을 방지하기 위한 수분 흡수부(21)를 추가적으로 구비할 수 있다. 상기 수분 흡수부는 상기 도체(11)의 연선된 소선 사이 및/또는 상기 도체(11)의 외부에 형성될 수 있으며, 케이블에 침투한 수분을 흡수하는 속도가 빠르고, 흡수 상태를 유지하는 능력이 우수한 고흡수성 수지(super absorbent polymer; SAP)를 포함하는 분말, 테이프, 코팅층 또는 필름 등의 형태로 구성되어 케이블 길이방향으로 수분이 침투하는 것을 방지하는 역할을 한다. 또한, 상기 수분 흡수부는 급격한 전계 변화를 방지하기 위하여 반도전성을 가질 수 있다.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.
상기 케이블 코어부(10)의 외부에는 케이블 보호부(20)가 구비되며, 해저에 포설되는 전력케이블은 케이블 외장부(30)를 추가적으로 구비할 수 있다. 상기 케이블 보호부 및 케이블 외장부는 케이블의 전력 전송 성능에 영향을 미칠 수 있는 수분침투, 기계적 외상, 부식 등의 다양한 환경요인으로부터 코어부를 보호한다.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.
상기 케이블 보호부(20)는 금속시스(22)와 고분자 시스(24)를 포함하여, 사고전류, 외력 내지 기타 외부환경 요인으로부터 케이블을 보호한다.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.
상기 금속시스(22)는 상기 코어부(10)를 둘러싸도록 형성할 수 있다. 특히, 상기 전력 케이블이 해저와 같은 환경에 포설되는 경우, 수분과 같은 이물질이 상기 케이블 코어부(10)에 침입하는 것을 방지하기 위해 상기 케이블 코어부(10)를 실링하도록 형성할 수 있으며, 상기 케이블 코어부(10) 외부에 용융된 금속을 압출하여 이음새가 없는 연속적인 외면을 가지도록 형성하여 차수성능이 우수하게 할 수 있다. 상기 금속으로는 납(Lead) 또는 알루미늄을 사용하며, 해저에 포설되는 전력 케이블의 경우에는 해수에 대한 내식성이 우수한 납을 사용하는 것이 바람직하고, 기계적 성질을 보완하기 위해 금속 원소를 첨가한 합금연(Lead alloy)을 사용하는 것이더욱 바람직하다. 또한, 상기 금속시스(22)는 전력 케이블 단부에서의 접지되어 지락 또는 단락 등의 사고 발생시 사고 전류가 흐르는 통로 역할을 하며, 외부의 충격으로부터 케이블을 보호하고, 전계가 케이블 외부로 방전되지 못하도록 할 수 있다.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.
또한, 상기 금속시스(22)는 케이블의 내식성, 차수성 등을 추가로 향상시키고 상기 고분자 시스(24)와의 접착력을 향상시키기 위해 표면에 부식 방지 컴파운드, 예를 들어, 블로운 아스팔트 등이 도포될 수 있다.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.
뿐만 아니라, 상기 금속 시스(22)와 상기 케이블 코어부(10) 사이에는 동선직입 테이프 내지 수분 흡수층(21)이 추가적으로 구비될 수 있다. 상기 동선직입 테이프는 동선(Copper wire)과 부직포 테이프 등으로 구성되어 외부반도전층(16)과 금속시스(22)간의 전기적 접촉을 원활히 하는 작용을 하며, 상기 수분흡수층은 케이블에 침투한 수분을 흡수하는 속도가 빠르고, 흡수 상태를 유지하는 능력이 우수한 고흡수성 수지(super absorbent polymer; SAP)를 포함하는 분말, 테이프, 코팅층 또는 필름 등의 형태로 구성되어 케이블 길이방향으로 수분이 침투하는 것을 방지하는 역할을 한다. 또한, 상기 동선직입 테이프와 수분 흡수층은 급격한 전계 변화를 방지하기 위해 반도전성을 가지는 것이 바람직하며, 통전 및 수분흡수 작용을 모두 할 수 있도록, 수분 흡수층에 동선을 포함시켜 구성할 수도 있다.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.
상기 고분자 시스(24)는 상기 금속시스(22)의 외부에 형성되어 케이블의 내식성, 차수성 등을 향상시키고, 기계적 외상 및 열, 자외선 등의 기타 외부 환경 요인으로부터 케이블을 보호하는 기능을 수행할 수 있다. 상기 고분자 시스(24)는 폴리염화비닐(PVC), 폴리에틸렌 등과 같은 수지로 형성될 수 있으며, 해저에 포설되는 전력 케이블의 경우에는 차수성이 우수한 폴리에틸렌 수지를 사용하는 것이 바람직하며, 난연성이 요구되는 환경에서는 폴리염화비닐 수지를 사용하는 것이 바람직하다.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.
상기 전력 케이블(100)은 상기 고분자 시스의 내측 또는 외측에 아연도금 처리된 강철 테이프 등으로 구성되는 금속 보강층(26)을 구비하여, 상기 절연유의 팽창에 의해 상기 금속시스(22)가 팽창하는 것을 방지할 수 있다. 또한, 상기 금속 보강층(26)의 상부 및/또는 하부에는 반도전성 부직포 테이프 등으로 이루어져 전력 케이블에 가해지는 외력을 완충하는 베딩층(미도시)을 구비할 수 있으며, 폴리염화비닐 내지 폴리에틸렌 등의 수지로 구성되는 외부 시스(28)를 더 구비하여 전력 케이블의 내식성, 차수성 등을 더욱 향상시키고, 기계적 외상 및 열, 자외선 등의 기타 외부 환경 요인으로부터 케이블을 추가적으로 보호할 수 있다.The power cable 100 includes a metal reinforcing layer 26 formed of a galvanized steel tape or the like on the inside or the outside of the polymer sheath so that the metal sheath 22 is expanded by the expansion of the insulating oil. You can prevent it. 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.
또한, 해저에 포설되는 전력 케이블은 선박의 닻 등에 의해 외상을 입기 쉬우며, 해류나 파랑 등에 의한 굽힘력, 해저면과의 마찰력 등에 의해서도 파손될 수 있으므로 이를 막기 위하여 상기 케이블 보호부의 외부에 케이블 외장부(30)를 추가로 구비할 수 있다.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.
상기 케이블 외장부는 아머층(34) 및 써빙층(38)을 포함할 수 있다. 상기 아머층(34)은 강철, 아연도금강, 구리, 황동, 청동 등으로 이루어지고 단면 형태가 원형, 평각형 등인 와이어를 횡권하여 적어도 1층 이상으로 구성할 수 있으며, 상기 전력 케이블의 기계적 특성과 성능을 강화하는 기능을 수행할 뿐만아니라 외력으로부터 케이블을 추가적으로 보호한다.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.
폴리프로필렌 얀 등으로 구성되는 상기 써빙층(38)은 상기 아머층(34)의 상부 및/또는 하부에 1층 이상으로 형성되어 케이블을 보호하며, 최외곽에 형성되는 써빙층(34)은 색상이 다른 2종 이상의 재료로 구성되어 해저에서 포설된 케이블의 가시성을 확보할 수 있다.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.
도 3은 본 발명에 따른 중간접속함 및 이를 이용하여 한 쌍의 전력 케이블을 접속한 직류 전력케이블 중간접속시스템을 개략적으로 나타내는 부분 절개도이다. 상세하게는 중간접속함(200)에 의해 도 1과 같은 구성을 가지는 직류 전력 케이블(100A, 100B)이 서로 접속된 상태를 개략적으로 도시한 부분절개도이다.3 is a partial cutaway view schematically showing an intermediate junction box according to the present invention and a DC power cable intermediate connection system connecting a pair of power cables using the same. In detail, it is a partial cutaway view schematically showing a state in which the DC power cables 100A and 100B having the configuration as shown in FIG. 1 are connected to each other by the intermediate junction box 200.
도 3를 참조하면, 도체(11A), 내부반도전층(12), 케이블 절연층(14) 및 외부반도전층(16)이 순차적으로 노출된 상기 한 쌍의 직류 전력케이블(100A, 100B)의 단부가 서로 대향하도록 구비되고, 상기 한 쌍의 도체(11A, 11B)의 단부를 서로 연결하는 도체 접속부, 상기 도체 접속부를 둘러싸도록 형성되는 보강절연층(210), 상기 보강절연층을 둘러싸도록 형성되며 상기 케이블의 외부반도전층(16) 내지 금속시스(22)와 통전되는 접속함 외부반도전층(230)을 포함하는 중간접속함이 형성된다.Referring to FIG. 3, ends of the pair of DC power cables 100A and 100B in which the conductor 11A, the inner semiconducting layer 12, the cable insulation layer 14, and the outer semiconducting layer 16 are sequentially exposed. Are provided to face each other, a conductor connecting portion connecting the ends of the pair of conductors 11A and 11B to each other, a reinforcing insulating layer 210 formed to surround the conductor connecting portion, and formed to surround the reinforcing insulating layer. An intermediate junction box including a junction box outer semiconducting layer 230 that is energized with the outer semiconducting layer 16 to the metal sheath 22 of the cable is formed.
상기 도체접속부는 상기 노출된 한 쌍의 도체를 전기적, 기계적으로 연결하여 접속하며, 상기 한 쌍의 도체 단부 사이에 필러금속(M)을 충진하여 접속하거나, 도체 압착슬리브를 이용하여 상기 한 쌍의 도체 단부를 파지하여 접속할 수 있다.The conductor connection part electrically connects the exposed pair of conductors electrically and mechanically, and fills and connects the filler metal (M) between the pair of conductor ends, or connects the pair of conductors using a conductor crimp sleeve. The conductor end can be gripped and connected.
상기 필러금속(M)은 사선으로 절단된 단부가 서로 대향하도록 구비된 한 쌍의 도체 단부 사이에 브레이징 또는 아크 용접 등의 접합 공정을 이용하여 상기 도체(11A, 11B)의 직경에 비해 크게 필러 금속(Filler metal)을 녹여 붙인 후 그라인딩 등의 기계 가공을 하여 상기 한 쌍의 도체 단부 사이에 충진시킬 수 있다.The filler metal (M) is larger than the diameter of the conductors (11A, 11B) by using a bonding process such as brazing or arc welding between the pair of conductor ends provided with diagonally cut ends facing each other. (Filler metal) can be melted and glued and then machined such as grinding to fill between the pair of conductor ends.
상기 도체 압착슬리브를 이용하는 경우, 상기 도체 압착슬리브는 압착된 후의 외경이 상기 노출된 한 쌍의 도체(11A, 11B)의 외경과 대략 유사한 동경압착슬리브일 수 있으며, 상기 노출된 한 쌍의 도체(11A, 11B)의 각 단부에 도체 압착슬리브를 끼운 후 상기 도체 압착슬리브의 외면을 압착하여 형성할 수 있고, 상기 도체 압착슬리브의 외면을 압착한 후 그라인딩 등의 기계 가공을 하여 외면을 평활하게 할 수 있다. 상기 도체 압착슬리브는 상기 한 쌍의 도체(11A, 11B) 단부를 서로 고정하여, 상기 전력케이블 내지 상기 전력케이블 중간접속시스템이 포설되는 경우에 장력이 작용하더라도 상기 한 쌍의 도체가 서로 전기적으로 접속된 상태를 견고히 지지한다. When the conductor crimp sleeve is used, the conductor crimp sleeve may be a copper crimp sleeve whose outer diameter after being crimped is approximately similar to that of the exposed pair of conductors 11A and 11B, and the exposed pair of conductors ( 11A, 11B) by inserting a conductor crimp sleeve at each end of the conductor crimp sleeve can be formed by crimping the outer surface of the conductor crimp sleeve, and the outer surface of the conductor crimp sleeve is crimped and then machined such as grinding to smooth the outer surface. Can be. The conductor crimp sleeve fixes the ends of the pair of conductors 11A and 11B to each other so that the pair of conductors are electrically connected to each other even when tension is applied when the power cable to the power cable intermediate connection system are installed. I firmly support the state which was made.
필러금속(M)을 충진한 후 그라인딩을 하거나, 상기 동경압착슬리브를 압축한 후 표면을 다듬질하는 경우에는 상기 도체접속부가 상기 케이블 도체와 대략 동일한 외경을 가지게 되므로 상기 도체접속부 상에 형성되는 상기 보강절연층의 두께를 줄일 수 있다. When the filler metal (M) is filled and ground or the surface is compressed after compressing the copper crimping sleeve, the conductor connecting portion has the same outer diameter as the cable conductor, so the reinforcement formed on the conductor connecting portion The thickness of the insulating layer can be reduced.
상기 노출된 케이블 절연층(14A)은 단일 경사면을 갖도록 펜슬링될 수 있다. 일 예로서 도 3 및 4에 도시된 바와 같이 케이블 절연층(14A)은 노출된 도체(11A)와의 각도가 둔각이 되는 단일 경사면(S)을 가질 수 있다.The exposed cable insulation layer 14A may be penciled to have a single slope. As an example, as shown in FIGS. 3 and 4, the cable insulation layer 14A may have a single inclined surface S whose angle with the exposed conductor 11A is an obtuse angle.
상기 도체접속부를 형성하여 상기 절연유 함침 케이블(100A, 100B)의 각 도체(11A, 11B)를 접속한 후 상기 도체접속부를 비롯한 케이블 절연층(14A)의 적어도 일부를 감싸는 보강절연층(210)을 형성하여 상기 도체 및 도체접속부를 통해 흐르는 전류가 상기 중간접속시스템의 길이방향으로만 흐르고, 반경방향으로 누설되는 것을 방지한다. The conductor connecting portion is formed to connect the respective conductors 11A and 11B of the insulating oil impregnated cable 100A and 100B, and then a reinforcing insulating layer 210 covering at least a part of the cable insulating layer 14A including the conductor connecting portion is formed. The current flowing through the conductor and the conductor connecting portion flows only in the longitudinal direction of the intermediate connecting system and prevents leakage in the radial direction.
상기 보강절연층(210)은 상기 도체 접속부, 상기 노출된 내부반도전층 내지 케이블 절연층을 둘러싸도록 절연지를 권취하여 형성할 수 있으며, 상기 보강절연층(210)을 이루는 상기 절연지는 절연내력이 우수한 복합 절연지일 수 있고, 상기 복합 절연지보다 체적저항률이 낮은 절연지, 예를 들면 크래프트지를 더 포함하여 복합 절연지와 크래프트지의 체적저항률 차이를 이용한 전계제어를 할 수 있다.The reinforcing insulating layer 210 may be formed by winding insulating paper to surround the conductor connecting portion, the exposed inner semiconducting layer or the cable insulating layer, and the insulating paper forming the reinforcing insulating layer 210 has excellent insulating strength. The composite insulating paper may further include an insulating paper having a lower volume resistivity than the composite insulating paper, for example, kraft paper, so that electric field control may be performed using a difference in volume resistivity between the composite insulating paper and the kraft paper.
상기 보강절연층(210)은 상기 도체 접속부, 상기 노출된 내부반도전층 내지 케이블 절연층을 둘러싸도록 절연지가 권취되어 상기 케이블 절연층 외경까지 형성되는 제1 보강절연층(2101) 및 상기 제1 보강절연층(2101)과 상기 제1 보강절연층을 둘러싸도록 형성되는 제2 보강절연층(2102)으로 이루어질 수 있다. The reinforcement insulating layer 210 may include a first reinforcement insulating layer 2101 and a first reinforcement formed by winding insulating paper to surround the conductor connecting portion, the exposed inner semiconducting layer or the cable insulating layer. The insulating layer 2101 and the second reinforcing insulating layer 2102 formed to surround the first reinforcing insulating layer may be formed.
상기 제2 보강절연층(2102)은 상기 제1 보강절연층(2101) 및 상기 노출된 케이블 절연층(14A)을 둘러싸도록 형성된다. 즉, 상기 제2 보강절연층(2102)은 케이블 절연층 외경 이상에 형성되어 상기 중간접속함의 절연 성능을 향상시킨다. The second reinforcement insulating layer 2102 is formed to surround the first reinforcement insulating layer 2101 and the exposed cable insulating layer 14A. That is, the second reinforcement insulating layer 2102 is formed above the outer diameter of the cable insulating layer to improve the insulation performance of the intermediate junction box.
또한, 상기 제2 보강절연층(2102)은 상기 케이블 길이방향으로의 폭이 상기 케이블의 방사방향으로 일정한 직선부(2102A)와, 상기 직선부의 양단에 형성되며 상기 케이블 길이방향으로의 폭이 상기 케이블의 방사방향으로 감소하는 슬로프부(2102B)를 구비할 수 있다.In addition, the second reinforcement 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 is formed at both ends of the straight portion, and the width of the second reinforcement insulating layer 2102 is in the cable length direction. It may have a slope portion 2102B which decreases in the radial direction of the cable.
상기 슬로프부(2102B)는 상기 직선부(2102A)의 양단에 형성되며 후술하는 접속함 외부반도전층(230)의 형상을 결정하여 전계를 제어하는 역할을 한다. 구체적으로, 상기 케이블 길이방향으로의 폭이 상기 케이블의 방사방향으로 감소하도록 형성되어 상기 케이블 측의 단부에서 상기 직선부 측의 단부를 향하여 상기 슬로프부의 두께가 두꺼워진다. 또한, 상기 두께의 증가율이 커질 수 있으며, 이 경우, 슬로프부는 곡면으로 형성되는 외면을 가질 수 있다. 즉, 상기 슬로프부(210B)는 케이블 도체(11A, 11B) 단부 방향으로 갈수록 슬로프부 외면의 기울기가 점점 커지도록 형성할 수 있다.The slope portion 2102B is formed at both ends of the straight portion 2102A and serves to control the electric field by determining the shape of the junction box outer semiconducting layer 230 to be described later. Specifically, the width in the longitudinal direction of the cable is formed to decrease in the radial direction of the cable so that the thickness of the slope portion becomes thicker from the end of the cable side toward the end of the straight portion side. In addition, the increase rate of the thickness may be increased, and in this case, the slope part may have an outer surface formed as a curved surface. That is, the slope portion 210B may be formed such that the slope of the outer surface of the slope portion increases gradually toward the end direction of the cable conductors 11A and 11B.
상기 제2 보강절연층(2102)은 도 3 내지 도 4에 도시된 바와 같이 방사방향으로 적층된 복수의 절연지층(2102L)으로 형성될 수 있으며, 상기 절연지층(2102L)은 절연지를 권취하여 상기 케이블 내지 중간접속함의 방사방향으로 절연지를 적층함으로써 형성될 수 있다.As shown in FIGS. 3 to 4, the second reinforcement insulating layer 2102 may be formed of a plurality of insulating paper layers 2102L stacked in a radial direction, and the insulating paper layer 2102L may be wound around the insulating paper. It can be formed by laminating insulating paper in the radial direction of the cable to the intermediate junction box.
상기 복수개의 절연지층(2102L)은 소정의 길이를 가지는 절연지가 길이 방향으로 연속되지 않아서 상기 케이블 내지 상기 중간접속함 방사방향으로 구분되어지는 절연지층으로 형성된 것을 의미한다. 구체적으로, 소정의 길이를 가지는 절연지가 길이방향으로 감겨진 절연지롤을 사용하여 절연지를 지권함으로써 하나의 절연지층을 형성할 수 있으며, 상기 소정의 길이를 가지는 절연지를 모두 권취하면, 다시 새로운 절연지롤을 사용하여 절연지를 권취하여 다른 절연지층을 형성하는 과정을 반복하며, 복수개의 절연지롤을 이용하여 복수개의 절연지층을 형성한다. 따라서, 상기 각각의 절연지층(2102L)은 권취된 절연지가 연속되지 않는바 상기 케이블 내지 중간접속함의 방사방향으로 구분지어 진다. 상기 하나의 절연지롤은 폭이 좁아지거나 커지는, 대략 사다리꼴의 형상을 가지는 절연지가 길이방향으로 감겨있을 수 있으며, 상기 복수개의 절연지롤 각각을 이루는 절연지는 서로 상기 폭의 변화율 또는 절연지의 길이가 상이할 수 있다. 즉 다양한 형상을 가지는 절연지를 사용하여 복수개의 절연지층(212L)을 형성하므로 상기 제2 보강절연층(2102)의 형상, 특히 상기 슬로프부(2102B)의 형상을 정밀하게 제어할 수 있다. The plurality of insulating paper layers 2102L means that the insulating paper having a predetermined length is not formed in the longitudinal direction and is formed of an insulating paper layer which is divided in the radial direction of the cable to the intermediate junction box. Specifically, one insulating paper layer can be formed by winding the insulating paper using an insulating paper roll in which the insulating paper having a predetermined length is wound in the longitudinal direction. When all the insulating paper having the predetermined length is wound, a new insulating paper roll is again. Repeating the process of forming another insulating paper layer by winding the insulating paper using, to form a plurality of insulating paper layers using a plurality of insulating paper rolls. Thus, each of the insulating paper layers 2102L is divided in the radial direction of the cable to the intermediate junction bar because the wound insulating paper is not continuous. The one sheet of insulating paper roll may have an insulating paper having a substantially trapezoidal shape in which the width of the insulating paper roll is narrowed or large, and the insulating paper forming each of the plurality of insulating paper rolls may have a different rate of change of the width or length of the insulating paper. Can be. That is, since the plurality of insulating paper layers 212L are formed by using insulating paper having various shapes, the shape of the second reinforcing insulating layer 2102, in particular, the shape of the slope portion 2102B can be precisely controlled.
상기 제2 보강절연층(2102)은 동일한 절연지층 내에서 절연지는 케이블 내지 접속함의 길이방향으로 연속되지 않아 구분되는 복수개의 절연지 권취부(W, N)를 포함할 수 있다. 즉, 하나의 절연지층(2102L)은 케이블의 길이방향으로 복수개의 절연지 권취부(W, N)로 구분될 수 있다. 절연유에 함침된 절연지를 포함하는 상기 제2 보강절연층(2102)에 있어서, 상기 복수개의 절연지 권취부(W, N)는 절연유 유동로의 역할을 한다. 특히, 상기 절연지가 플라스틱 필름을 포함하는 복합 절연지인 경우, 상기 절연유가 상기 플라스틱 필름을 통과하여 유동하지 못하므로, 절연유 함침시 내지 열에 의한 절연유 팽창시 상기 복수개의 절연지 권취부 사이로 절연유가 유동할 수 있는 장점이 있다.The second reinforcement insulating layer 2102 may include a plurality of insulating paper windings W and N which are separated from each other because the insulating paper is not continuous in the longitudinal direction of the cable or the junction box in the same insulating paper layer. That is, one insulating paper layer 2102L may be divided into a plurality of insulating paper windings W and N in the longitudinal direction of the cable. In the second reinforcement insulating layer 2102 including insulating paper impregnated with insulating oil, the plurality of insulating paper windings W and N serve as an insulating oil flow path. In particular, when the insulating paper is a composite insulating paper containing a plastic film, the insulating oil does not flow through the plastic film, the insulating oil may flow between the plurality of insulating paper winding when the insulating oil impregnated to expand the insulating oil by heat. There is an advantage.
본 발명에 있어서, 상기 절연지 권취부(W, N)는 상면, 하면 내지 측면 중 적어도 한 부분에서 다른 절연지 권취부와 접할 수 있다. 구체적으로, 상기 절연지 권취부는 상면 내지 하면에서 다른 절연지층의 절연지 권취부와 접할 수 있거나, 측면에서 동일한 절연지층의 다른 절연지 권취부와 접할 수 있다. 이 때 임의의 절연지 권취부가 동일한 층을 구성하는 다른 절연지 권취부, 특히 측면에 접하고 있는 절연지 권취부에 비하여 폭이 현저히 작은 절연지가 횡권되어 케이블의 길이방향 및 방사방향으로 권취되어 있고, 상면 내지 하면 중 적어도 어느 한 부분에서 하나의 절연지 권취부와 접하고 있으면 이를 세폭지 권취부(N)라고 정의할 수 있으며, 상기 세폭지 권취부(N)를 이루고 있는 절연지 보다 현저히 큰 폭을 가지는 절연지를 포함하는 절연지 권취부를 광폭지 권취부(W)로 정의할 수 있다. In the present invention, the insulating paper winding portion (W, N) may be in contact with the other insulating paper winding portion on at least one of the upper surface, the lower surface to the side. Specifically, the insulating paper winding portion may be in contact with the insulating paper winding portion of the other insulating paper layer from the upper surface to the lower surface, or may be in contact with other insulating paper winding portion of the same insulating paper layer from the side. At this time, an insulated paper winding part of which an insulated paper winding part constitutes the same layer, especially an insulated paper winding having a significantly smaller width than that of the insulated paper winding part which is in contact with the side, is wound in the longitudinal direction and the radial direction of the cable. If it is in contact with at least one of the insulating paper winding portion may be defined as narrow paper winding portion (N), including an insulating paper having a significantly larger width than the insulating paper forming the narrow paper winding portion (N). The insulated paper winding portion may be defined as the wide paper winding portion (W).
상기 제2 보강절연층(2102)은 상기 세폭지 권취부(N)와 광폭지 권취부(W)를 포함하여 상기 슬로프부(2102B)의 형상을 정밀하게 구현할 수 있다. 특히, 상기 제2 보강절연층(2102)을 이루는 복수개의 절연지층 중 상기 제2 보강절연층의 최외곽층을 이루는 절연지층 보다 작은 외경을 가지는 절연지층 각각은 광폭지 권취부(W)와 적어도 하나 이상의 세폭지 권취부(N)로 형성되어 제2 보강절연층(2102)의 슬로프부(2102B)의 형상을 정밀하게 구현할 수 있다. The second reinforcement insulating layer 2102 may include the narrow winding portion N and the wide winding portion W to precisely implement the shape of the slope portion 2102B. In particular, each of the insulating paper layers having a smaller outer diameter than the insulating paper layer forming the outermost layer of the second reinforcing insulating layer among the plurality of insulating paper layers constituting the second reinforcing insulating layer 2102 is at least one of the wide-wound winding W; One or more narrow paper winding parts N may be formed to precisely implement the shape of the slope part 2102B of the second reinforcement insulating layer 2102.
구체적으로, 광폭지를 권취하여 상기 슬로프부 및 상기 직선부의 일부에 복수 개의 광폭지 권취부(W)를 형성한 후 상기 광폭지 권취부(W)들 사이의 형성된 빈 공간을 세폭지로 권취하여 세폭지 권취부(N)를 형성할 수 있다.Specifically, after winding the wide paper to form a plurality of wide paper winding portion (W) on the slope portion and the portion of the straight portion, and then winding the empty space formed between the wide paper winding portion (W) by narrow paper to narrow paper The winding part N can be formed.
상기 광폭지 권취부(W)는 대략 사다리꼴 모양의 광폭지를 권취하여 미리 결정된 모양의 절연지 권취부, 특히 상기 슬로프면의 외면이 소정의 기울기를 가지도록 하는 미리 결정된 모양의 절연지 권취부를 형성할 수 있다. 따라서, 작업성이 우수하며, 상기 광폭지를 권취하여 상기 슬로프부(2102B)를 형성함으로써, 상기 슬로프부(2102B)의 외면 형상을 정밀하게 제어할 수 있다.The wide paper winding portion W may form an insulated paper winding portion having a predetermined shape by winding a wide trapezoidal shape, particularly an insulated paper winding portion having a predetermined slope so that an outer surface of the slope surface has a predetermined slope. . Therefore, it is excellent in workability and can form the slope part 2102B by winding the said wide paper, and can control the external shape of the slope part 2102B precisely.
다만, 광폭지를 권취하는 과정에서 오차가 발생하는 경우, 상기 광폭지 권취부(W)들 사이에 형성된 빈 공간에는 미리 결정된 모양을 가지는 절연지 권취부를 형성할 수 없다. 따라서, 상기 광폭지 권취부(W)들 사이에 형성된 빈 공간에는 상기 세폭지를 횡권하여 상기 케이블의 길이방향 및 방사방향으로 권취하여 세폭지 권취부(N)를 형성하는 것이 바람직하다. 즉, 미리 결정된 형태의 절연지 권취부를 형성하는 광폭지 권취부(W)와는 달리, 상기 세폭지 권취부(N)는 폭이 작은 절연지를 상기 케이블의 길이방향으로 횡권하며 방사방향으로 권취하여 형성되는바 상기 광폭지 권취부(W) 형성시 발생한 오차를 보상하여 상기 제2 보강절연층의 형상을 정밀하게 제어할 수 있다. However, when an error occurs in the process of winding the wide paper, the insulating paper winding portion having a predetermined shape may not be formed in the empty space formed between the wide paper winding portions W. Therefore, it is preferable to form the narrow paper winding portion N by winding the narrow paper horizontally and winding in the longitudinal direction and the radial direction of the cable in the empty space formed between the wide paper winding portions W. That is, unlike the wide paper winding portion W which forms the insulating paper winding portion of a predetermined shape, the narrow paper winding portion N is formed by winding a small width of the insulating paper in the longitudinal direction of the cable and winding in the radial direction. The shape of the second reinforcement insulating layer may be precisely controlled by compensating for an error generated when the wide area winding unit W is formed.
상기 세폭지 권취부(N)는 광폭지에 비하여 상대적으로 그 폭이 작은 절연지를 중간접속함 길이방향 및 방사 방향으로 권취하여 형성하는바, 길이방향으로 권취된 절연지 사이의 틈이 많으며, 상기 틈이 밀집되어 있다. 상기 틈은 절연파괴의 시점이 될 수 있는 공극으로 작용할 가능성이 크며, 상기 공극이 밀집되는 경우에는 국부적인 체적저항률 변화로 전계왜곡이 발생할 우려가 있어 절연취약부로 작용할 수 있다. 따라서, 세폭지 권취부(N)는 슬로프부(2102B)가 아닌 상대적으로 절연지가 두껍게 권취되어 있는 직선부(2102A)에만 형성되는 것이 바람직하다. The narrow paper winding portion (N) is formed by winding an insulating paper having a relatively smaller width than that of a wide paper paper in the longitudinal and radial directions of the intermediate junction box, and has a large gap between the insulating paper wound in the longitudinal direction. It is concentrated. The gap is likely to act as a gap that can be the point of breakdown, and when the gap is dense, there is a risk of electric field distortion due to a local volume resistivity change may act as an insulation weakening. Therefore, it is preferable that the narrow paper winding portion N is formed only in the straight portion 2102A in which the insulation paper is relatively thickly wound, not the slope portion 2102B.
또한, 상기 슬로프부(2102B)의 각 절연지층은 하나의 광폭지 권취부(W)로 이루어질 수 있다. 즉 상기 슬로프부(2102B)에는 광폭지 권취부(W)와 그에 접하는 광폭지 권취부(W)가 만나는 맞대기부(C)가 형성되지 않을 수 있으며, 상기 슬로프부(2102B)를 형성하는 광폭지 권취부(W)는 제2 보강절연층(2102)의 직선부(2102A)로 연장될 수 있다. 광폭지 권취부(W)의 절연지 및 그에 접하는 광폭지 권취부의 절연지 사이에는 틈이 있을 수 있으며, 상기 틈은 공극으로 작용할 수 있는바, 상기 맞대기부(C)는 상대적으로 절연지가 두껍게 권취되어 있는 직선부(2102A)에만 형성되는 것이 바람직하다. In addition, each insulating paper layer of the slope part 2102B may be formed of one wide paper winding part (W). That is, the butt portion C, in which the wide paper winding portion W and the wide paper winding portion W contacting each other, may not be formed in the slope portion 2102B, and the wide paper forming the slope portion 2102B may be formed. The winding part 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 paper winding portion W and the insulating paper in contact with the wide paper winding portion, and the gap may act as a gap, and the butt portion C may be relatively wound with a thick insulating paper. It is preferable to be formed only in the straight line portion 2102A.
상술한 바와 같이 상기 세폭지 권취부(N)는 상기 제2 보강절연층의 형상을 정밀하게 형성할 수 있는 반면, 절연취약부로 작용할 우려가 있다. 따라서, 제2 보강절연층(2102)의 절연지층(2102L) 각각은 세폭지 권취부(N)의 개수가 맞대기부(C) 개수 이하가 되도록 하여 세폭지 권취부의 개수를 최소화할 수 있다. 상기 맞대기부(C)는 같은 절연치층(2102L) 내에서 서로 다른 광폭지 권취부(W)가 접하는 계면을 의미한다.As described above, the narrow paper winding portion N may precisely form the shape of the second reinforcement insulating layer, but may act as an insulating weakening portion. Accordingly, each of the insulating paper layers 2102L of the second reinforcement insulating layer 2102 may have the number of narrow paper winding portions N less than or equal to the butt portion C, thereby minimizing the number of narrow paper winding portions. The butt portion C means an interface where different wide-area winding portions W contact each other in the same insulating tooth layer 2102L.
다만, 상기 제2 보강절연층(2102)의 최외곽 절연지층은 세폭지 권취부(N)의 개수가 맞대기부(C) 개수 이하가 아닐 수 있다. 즉, 제2 보강절연층(2102)의 최외곽 절연지층의 길이가 짧은 경우에는 광폭지 권취부(W)만으로 절연지층을 형성하거나, 맞대기부를 포함하지 않고 2개의 광폭지 권취부(W) 및 상기 2개의 광폭지 권취부 사이에 형성된 하나의 세폭지 권취부(N)만을 포함할 수도 있다.However, in the outermost insulating paper layer of the second reinforcing insulating layer 2102, the number of narrow paper winding portions N may not be equal to or less than the number of butt portions C. FIG. That is, when the length of the outermost insulating paper layer of the second reinforcing insulating layer 2102 is short, the insulating paper layer is formed only by the wide paper winding part W, or two wide paper winding parts W and not including butt parts are formed. It may include only one narrow paper winding portion (N) formed between the two wide paper winding portion.
이와 같이 광폭지 권취부(W)에 비해 상대적으로 절연에 취약한 세폭지 권취부(N)를 최소로 하여 절연지층(2102L)을 형성함으로써 제2 보강절연층(2102)의 절연 성능을 향상시킬 수 있다. As such, the insulation performance of the second reinforcing insulation layer 2102 may be improved by forming the insulation paper layer 2102L with a minimum width of the narrow paper winding portion N, which is relatively weak to insulation, compared to the wide paper winding portion W. have.
또한, 상기 제2 보강절연층(2102)은 서로 인접한 절연지층(212L1, 212L2) 각각에 형성된 세폭지 권취부(N1, N2)를 상하방향으로 중첩시키지 않고 소정의 거리(D1)만큼 서로 이격시켜 형성함으로써, 세폭지를 권취함으로써 발생할 수 있는 공극 밀집이 중첩되는 것을 방지하여 중간접속함의 절연성능을 보다 향상시킬 수 있다. In addition, the second reinforcement insulating layers 2102 are spaced apart from each other by a predetermined distance D1 without overlapping the narrow paper winding portions N1 and N2 formed in the insulating paper layers 212L1 and 212L2 adjacent to each other in the vertical direction. By forming it, it is possible to prevent overlapping of void density generated by winding narrow paper, thereby further improving the insulation performance of the intermediate junction box.
구체적으로, 도 4에서와 같이 제2 보강절연층(2102)의 어느 한 절연지층(2102L)의 세폭지 권취부(N1)와 상기 어느 한 절연지층과 인접한 절연지층(2102L2)의 세폭지 권취부(N2)가 서로 이격된 거리(D1)는 상기 어느 한 절연지층(2102L1)의 세폭지 권취부(N1)와 상기 인접합 절연지층(2102L2)의 맞대기부(C1, C2)간의 거리(D2, D3) 중 최단거리(D2) 보다 크거나 같을 수 있다. 즉, 상기 절연지층(2102L1)에 인접한 절연지층(2102L2) 상에 한 개의 세폭지 권취부(N2)와 두 개의 맞대기부(C1, C2)가 존재하는 경우, 상기 절연지층(2102L1)의 세폭지 권취부(N1)와 상기 절연지층(2102L1)에 인접한 절연지층(2102L2)의 세폭지 권취부(N2) 사이의 거리(D1)는, 상기 절연지층(2102L1)의 세폭지 권취부(N1)와 상기 인접한 절연지층(2102L2)의 맞대기부(C1) 사이의 거리(D2)와, 상기 절연지층(2102L1)의 세폭지 권취부(N1)와 상기 인접한 절연지층(2102L2)의 맞대기부(C2) 사이의 거리(D3) 중 작은 거리보다 크거나 같을 수 있다. Specifically, as shown in FIG. 4, the narrow paper winding portion N1 of the insulating paper layer 2102L of the second reinforcing insulating layer 2102 and the narrow paper winding portion of the insulating paper layer 2102L2 adjacent to the insulating paper layer. The distance D1 spaced apart from each other is a distance D2 between the narrow paper winding portion N1 of the insulating paper layer 2102L1 and the butt portions C1 and C2 of the adjacent insulating paper layer 2102L2. It may be greater than or equal to the shortest distance D2 of D3). That is, when one narrow paper winding portion N2 and two butt portions C1 and C2 exist on the insulating paper layer 2102L2 adjacent to the insulating paper layer 2102L1, the narrow paper of the insulating paper layer 2102L1 is formed. The distance D1 between the winding portion N1 and the narrow paper winding portion N2 of the insulating paper layer 2102L2 adjacent to the insulating paper layer 2102L1 is equal to the narrow paper winding portion N1 of the insulating paper layer 2102L1. Between the distance D2 between the butt portion C1 of the adjacent insulating paper layer 2102L2, between the narrow paper winding portion N1 of the insulating paper layer 2102L1 and the butt portion C2 of the adjacent insulating paper layer 2102L2. It may be greater than or equal to the smaller of the distance (D3) of.
또한, 상기 어느 한 절연지층에 인접한 절연지층에 한 개의 세폭지 권취부와 한 개의 맞대기부만 존재하는 경우, 상기 어느 한 절연지층의 세폭지 권취부와 상기 인접한 절연지층의 세폭지 권취부 사이의 거리는 상기 어느 한 절연지층의 세폭지 권취부와 상기 인접한 절연지층의 맞대기부 사이의 거리보다 크거나 같을 수 있다.In addition, when there is only one narrow paper winding portion and one butt portion in the insulating paper layer adjacent to any one of the insulating paper layers, between the narrow paper winding portion of the one insulating paper layer and the narrow paper winding portion of the adjacent insulating paper layer. The distance may be greater than or equal to the distance between the narrow paper winding of one of the insulating paper layers and the butt portion of the adjacent insulating paper layer.
상술한 바와 같이, 서로 다른 절연지 층의 세폭지 권취부가 서로 중첩되지 않도록 하되, 절연유 유동로 역할을 할 수 있는 맞대기부를 세폭지 권취부에 근접하여 형성함으로써, 세폭지부에 절연유가 잘 함침되도록 할 수 있다. As described above, the narrow winding portions of the different insulating paper layers do not overlap each other, but the butt which may serve as the insulating oil flow path is formed close to the narrow paper winding portion, so that the insulating oil is well impregnated in the narrow paper portion. have.
상기 제1 보강절연층(2101)은 상기 도체 접속부, 상기 노출된 내부반도전층 및 케이블 절연층을 둘러싸도록 절연지가 권취되어 상기 케이블 절연층 외경까지 형성된다. 구체적으로 상기 제1 보강절연층(2101)은 서로 대향하도록 구비된 상기 한 쌍의 케이블에서 노출된 케이블 절연층 사이의 공간에 절연지를 횡권하여 상기 케이블의 길이방향으로 절연지를 권취하고 방사방향으로 절연지를 적층시킴으로써 형성할 수 있다.The first reinforcing insulating layer 2101 is formed by winding insulating paper to surround the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer, and formed to the outer diameter of the cable insulating layer. Specifically, the first reinforcing insulating layer 2101 is rolled up the insulating paper in the space between the cable insulating layer exposed from the pair of cables provided to face each other, wound the insulating paper in the longitudinal direction of the cable and insulated in the radial direction It can form by laminating | stacking.
상기 제1 보강절연층(2101)은 길이방향에서의 양 단부에 경사면(S)을 가질 수 있다. 상기 제1 보강절연층(2101)은 서로 대향하도록 구비된 상기 한 쌍의 케이블에서 노출된 케이블 절연층 사이의 공간에 형성되므로, 상기 제1 보강절연층(2101)의 길이방향 양단부는 상기 노출된 케이블 절연층의 단부 형상에 대응하도록 형성될 수 있다. 도3 및 도4에 도시된 바와 같이 케이블 절연층의 단부에 단일 경사면을 형성한 경우, 상기 케이블 절연층의 단일 경사면에 대응하도록 제1 보강절연층(2101)의 단부에 단일 경사면(S)을 형성함으로써 상기 제1 보강절연층(2101)과 케이블 절연층(14A) 사이의 계면길이를 경사면이 없는 경우에 비해 증가시킬 수 있으므로 절연성능이 향상된다.The first reinforcement insulating layer 2101 may have slopes S at both ends in the longitudinal direction. Since the first reinforcing insulating layer 2101 is formed in a space between the exposed cable insulating layers of the pair of cables provided to face each other, both ends of the first reinforcing insulating layer 2101 in the longitudinal direction are exposed. It may be formed to correspond to the end shape of the cable insulation layer. 3 and 4, when a single inclined surface is formed at the end of the cable insulation layer, a single inclined surface S is formed at the end of the first reinforcing insulation layer 2101 to correspond to the single inclined surface of the cable insulation layer. By forming, the interface length between the first reinforcing insulating layer 2101 and the cable insulating layer 14A can be increased as compared with the case where there is no inclined surface, so that the insulating performance is improved.
다만, 상기한 바와 같이 계면 길이를 증가시키는 경우에는 상기 중간 접속함의 길이가 길어지게 되며, 고객사의 요구 스팩, 또는 제조 단가 상 중간접속함의 길이를 제한없이 길게 구성할 수 없다. However, when the interface length is increased as described above, the length of the intermediate junction box becomes long, and the length of the intermediate junction box according to the specifications of the customer or the manufacturing unit price cannot be long.
또한, 계면 길이를 증가시키기 위해서 도 1에 도시된 종래 중간접속함에서와 같이 케이블 절연층을 펜슬링하여 단부에 다단 경사면을 형성하고, 이에 대응하는 다단 경사면을 단부에 가지는 제1 보강절연층을 형성할 수 있다. 다단 경사면을 가지는 상기 종래 중간접속함의 경우, 폭이 넓은 광폭지를 권취하여 형성하는 광폭지 권취부를 포함하여 작업성이 우수하며, 상기 광폭지에 비해 폭이 현저히 작은 세폭지가 케이블의 길이방향 및 방사방향으로 권취된 세폭지 권취부를 상기 다단 경사면에 형성함으로써, 상기 다단 경사면의 형상을 정밀하게 제어할 수 있다.In addition, in order to increase the interface length, as in the conventional intermediate junction box shown in FIG. 1, the cable insulation layer is penciled to form a multistage inclined surface at the end, and a first reinforcement insulating layer having a multistage inclined surface at the end thereof is provided. Can be formed. In the case of the conventional intermediate junction box having a multi-stage inclined surface, it has excellent workability, including a wide paper winding unit formed by winding a wide wide paper, and a narrow paper having a significantly smaller width than the wide paper in the longitudinal direction and the radial direction of the cable. The shape of the multi-stage inclined surface can be precisely controlled by forming the wound narrow paper winding portion in the multi-stage inclined surface.
하지만, 상기 세폭지 권취부는 광폭지에 비하여 그 폭이 현저히 작은 절연지를 중간접속함 길이방향 및 방사 방향으로 권취하여 형성하는바, 길이 방향으로 권취된 절연지 사이의 틈이 많으며, 상기 틈이 밀집되어 있다. 상기 틈은 절연파괴의 시점이 될 수 있는 공극으로 작용할 가능성이 크며, 상기 공극이 밀집되는 경우에는 국부적인 체적저항률 변화로 전계왜곡이 발생할 우려가 있는 절연취약부가 될 수 있다. 따라서, 종래 중간접속함은 경사면을 따라 형성된 세폭지 권취부와 광폭지 권취부가 형성된 부분과의 체적저항률 차이가 발생하여 다단 경사면에서 국부적으로 전계가 왜곡되어 절연파괴가 발생할 우려가 있다. However, the narrow paper winding part is formed by winding an insulating paper having a significantly smaller width than that of a wide paper paper in the longitudinal and radial directions of the intermediate junction box, and there are many gaps between the insulating paper wound in the longitudinal direction, and the gap is densified. . The gap is likely to act as a gap that can be the point of breakdown, and when the gap is densified, the gap may be an insulation weakness that may cause electric field distortion due to a local volume resistivity change. Therefore, the conventional intermediate junction box may have a difference in volume resistivity between the narrow paper winding portion formed along the inclined surface and the portion where the wide paper winding portion is formed, so that the electric field is locally distorted in the multi-stage inclined surface, which may cause insulation breakdown.
본 발명의 일 실시예에 따른 중간접속함은 상기 제1 보강절연층에 세폭지 권취부를 포함하지 않으면서도 정밀하게 형성된 경사면을 구비할 수 있으며, 작업성도 우수하다. 또한, 직류 전력케이블용 중간접속함의 길이가 비교적 짧으면서도 상기 경사면, 특히 상기 케이블 절연층과 상기 제1 보강절연층간의 계면의 연면전계 특성을 일정 수준으로 유지할 수 있고, 절연성능이 우수한 중간 접속시템을 제공할 수 있다.Intermediate junction according to an embodiment of the present invention may have an inclined surface formed precisely without including a narrow paper winding portion in the first reinforcing insulating layer, it is also excellent workability. In addition, the intermediate junction box for a DC power cable can maintain the creeping electric field characteristic of the interface between the inclined surface, in particular, the interface between the cable insulation layer and the first reinforcement insulation layer, while having a relatively short length, and has excellent insulation performance. You can provide the system.
구체적으로, 상기 제1 보강절연층(2101)을 형성하는 절연지는 그 폭이 제2 보강절연층(2102)의 세폭지 권취부(N)를 형성하는 절연지의 폭보다는 크고, 제2 보강절연층(2102)의 광폭지 권취부(W)를 형성하는 절연지의 폭보다는 작을 수 있다. 또한, 상기 절연지를 케이블 길이방향으로 이격되도록 횡권하여 형성할 수 있다.Specifically, the insulating paper forming the first reinforcing insulating layer 2101 is larger than the width of the insulating paper forming the narrow paper winding portion N of the second reinforcing insulating layer 2102, and the second reinforcing insulating layer It may be smaller than the width of the insulating paper forming the wide paper winding W of 2102. In addition, the insulating paper may be formed by lateral winding so as to be spaced apart in the cable longitudinal direction.
상기 제1 보강절연층(2101)을 제2 보강절연층(2102)의 세폭지 권취부(N)에서와 같이 지나치게 폭이 좁은 절연지를 사용하여 형성하는 경우에는 절연지 지권의 작업성이 떨어질 뿐만 아니라 공극이 발생할 확률이 매우 높다. 상기 제1 보강절연층(2101)을 상기 제2 보강절연층(2102)의 세폭지 권취부(N)를 형성하는 절연지의 폭보다는 크고 제2 보강절연층(2102)의 광폭지 권취부(W)를 형성하는 절연지의 폭보다는 작은 절연지로 형성함에 따라 세폭지로 형성하는 경우에 비해 공극이 발생할 가능성을 낮춤으로써 절연성능을 향상시킬 수 있다.When the first reinforcement insulating layer 2101 is formed using an insulating paper that is too narrow, such as in the narrow paper winding portion N of the second reinforcement insulating layer 2102, the workability of the insulating paper roll is not only poor. The chance of voids is very high. The wide reinforcement winding portion W of the second reinforcement insulating layer 2102 is larger than the width of the insulating paper forming the narrow paper winding portion N of the second reinforcement insulating layer 2102. By forming the insulating paper smaller than the width of the insulating paper forming the), it is possible to improve the insulation performance by reducing the possibility of voids compared to the case of forming a narrow paper.
또한, 상기 제1 보강절연층(2101)은 상기 제2 보강절연층(2102)의 세폭지 권취부(N)를 형성하는 절연지의 폭보다는 크고 제2 보강절연층(2102)의 광폭지 권취부(W)를 형성하는 절연지의 폭보다는 작은 절연지를 상기 케이블의 길이방향으로 이격시켜 횡권하며 상기 케이블의 길이방향 및 방사방향으로 권취하여 형성할 수 있다. 즉, 케이블의 길이방향으로 이격되어 횡권되는 절연지 사이 사이에 갭(Gap)이 형성되고, 상기 절연지가 상기 케이블 방사방향으로도 권취되어 상기 갭의 상부 및/또는 하부를 덮게 된다. 따라서, 상기 절연지를 상기 케이블의 길이방향으로 이격시켜 횡권할 때 발생하는 상기 절연지 간의 갭을 조절하며 상기 제1 보강절연층(2101)을 형성할 수 있으므로 상기 제1 보강절연층의 형상을 정밀하게 제어할 수 있으면서도, 상기 세폭지 권취부(N)가 없으므로 공극을 밀집시키지 않고 분산시킬 수 있는바 국부적인 전계왜곡을 방지하여 절연 안정성을 향상시킬 수 있다.In addition, the first reinforcement insulating layer 2101 is larger than the width of the insulating paper forming the narrow paper winding portion N of the second reinforcement insulating layer 2102 and the wide paper winding portion of the second reinforcement insulating layer 2102. The insulating paper smaller than the width of the insulating paper forming (W) may be spaced apart in the longitudinal direction of the cable and wound in the longitudinal and radial directions of the cable. That is, a gap Gap is formed between the insulating papers spaced apart in the longitudinal direction of the cable, and the insulating paper is also wound in the cable radial direction to cover the upper and / or lower portions of the gap. Accordingly, since the first reinforcing insulating layer 2101 can be formed while controlling the gap between the insulating papers generated when the insulating paper is spaced in the longitudinal direction of the cable, the shape of the first reinforcing insulating layer can be precisely formed. While controllable, since there is no narrow paper winding portion N, it is possible to disperse the voids without crowding, thereby preventing local electric field distortion and improving insulation stability.
상기 제1 보강절연층(2101)을 이루는 상기 절연지 층수는 케이블 절연층(14A)에 지권된 절연지 층수의 90% 이상일 수 있으며, 상기 제1 보강절연층(2101)을 이루는 상기 절연지는 반함침지일 수 있다. 여기서 반함침지는 절연지를 절연유에 함침한 후 절연유를 드레인(drain)시킨 절연지를 의미한다.The insulating paper layer forming the first reinforcing insulating layer 2101 may be 90% or more of the number of insulating paper layers supported on the cable insulating layer 14A, and the insulating paper forming the first reinforcing insulating layer 2101 is half impregnated. Can be. Here, the half impregnation refers to insulating paper in which insulating paper is impregnated with insulating oil and then drained.
상기 중간접속함은 상기 케이블의 금속시스(22)와 후술하는 금속차폐층이 접하는 부분에 형성되는 연공부 등 기계적인 성질이 취약한 부분을 포함하고 있기 때문에 절연유에 함침되지 않은 절연지인 건지로 상기 제1 보강절연층(2101)을 형성하는 경우, 고점도의 절연유를 함침시키기 위한 충분한 압력을 가하는데 어려움이 있으며, 충분한 압력을 가하지 못함에 따라 미함침으로 절연파괴가 발생할 우려가 있다.The intermediate junction box is an insulating paper which is not impregnated with insulating oil because it includes a weak mechanical property such as a softened portion formed at a portion where the metal sheath 22 and the metal shielding layer described later contact the cable. 1 When the reinforcing insulating layer 2101 is formed, it is difficult to apply sufficient pressure to impregnate the high-viscosity insulating oil, and there is a fear that insulation breakdown may occur due to unimpregnation due to insufficient pressure.
또한, 고점도의 절연유를 도포하며 상기 건지를 지권하거나, 고점도 절연유에 함침된 절연지인 유침지를 지권하는 경우, 기포 발생의 우려가 있을 뿐만 아니라, 권취된 절연지의 층수가 건지를 지권한 경우 대비 80% 수준으로 절연내력이 저하되는 문제가 있었다. In addition, if the application of high viscosity insulating oil is applied and the oil paper is impregnated, or the oil impregnated paper is impregnated with high viscosity insulating oil, not only there is a risk of bubbles, but the number of layers of wound insulation paper is 80% compared to the case of supporting the paper. There was a problem that the insulation strength is reduced to a level.
본 발명에 따르면, 유침지에서 1차적으로 기름을 제거한 반유침지를 지권하여 제1 보강절연층을 형성함으로써 건지를 권취한 경우에 비해 미함침 우려가 적고, 유침지를 권취한 경우 대비 상대적으로 많은 절연지를 지권할 수 있으므로 절연성능을 향상시킬 수 있다. 또한 상기 제1 보강절연층(2101)의 절연내력을 향상시킴으로써 상기 제2 보강절연층(2102)의 높이를 낮추고 보호동관(240)의 크기를 축소시켜 보호동관(240) 내 절연유 양을 감소시킬 수 있다. According to the present invention, there is less fear of impregnation compared to the case of winding dry paper by winding the semi-oil immersed oil which is primarily oil-depleted in the oil-impregnated paper to form the first reinforcement insulating layer. The insulation performance can be improved because In addition, by improving the dielectric strength of the first reinforcing insulating layer 2101, the height of the second reinforcing insulating layer 2102 is reduced and the size of the protective copper tube 240 is reduced to reduce the amount of insulating oil in the protective copper tube 240. Can be.
상기 중간접속함 및 이를 이용한 중간접속 시스템은 접속함 외부반도전층(230)이 더 형성될 수 있다. 상기 접속함 외부반도전층(230)은 상기 보강절연층(210)을 둘러싸도록 형성되며, 상기 케이블의 외부반도전층(16) 내지 금속시스(22)와 통전된다.In the intermediate junction box and the intermediate junction system using the same, the junction box outer semiconducting layer 230 may be further formed. The junction box outer semiconducting layer 230 is formed to surround the reinforcing insulating layer 210 and is energized with the outer semiconducting layer 16 to the metal sheath 22 of the cable.
상기 접속함 외부반도전층(230)은 제2 보강절연층(2102)의 슬로프부(2102B)의 외측면을 따라 형성되어 그 자체로 슬로프 형상을 가지는바, 케이블 절연층(14A)에서 중간접속함으로 연속되는 등전위선이 슬로프 형상을 갖는 상기 접속함 외부반도전층(230)의 기하학적인 형상에 따라 분포될 수 있다. 또한, 상기 접속함 외부반도층(230)은 케이블 절연층(14A, 14B), 보강절연층(210)에 비해 체적 저항이 낮을 수 있다. 즉, 접속함 외부반도전층(230)의 슬로프 형상 및 체적저항률을 이용하여 전계 분포를 제어할 수 있다.The junction box outer semiconducting layer 230 is formed along the outer surface of the slope portion 2102B of the second reinforcement insulating layer 2102 and has a slope shape by itself. Continuous equipotential lines may be distributed according to the geometric shape of the junction box outer semiconducting layer 230 having a slope shape. In addition, the junction box outer semiconducting layer 230 may have a lower volume resistance than the cable insulating layers 14A and 14B and the reinforcing insulating layer 210. That is, the electric field distribution may be controlled using the slope shape and the volume resistivity of the junction box external semiconducting layer 230.
상기 접속함 외부반도전층(230)은 상기 제2 보강절연층의 슬로프부(2102B) 외면에 반도전테이프를 권취함으로써 형성될 수 있으며, 상기 케이블의 외부반도전층(16)과 통전될 수 있다. 또한 상기 제2 보강절연층(2102)의 직선부(2102A)를 둘러싸도록 형성될 수도 있다.The junction box outer semiconducting layer 230 may be formed by winding a semiconducting tape on the outer surface of the slope portion 2102B of the second reinforcement insulating layer, and may be energized with the outer semiconducting layer 16 of the cable. In addition, the second reinforcement insulating layer 2102 may be formed to surround the straight portion 2102A.
이어서, 상기 케이블(100A)의 금속시스(22)와 통전되는 금속차폐층이 상기 보강절연층(210) 상에 복원되고, 스페이서(250) 및 보호동관(240)이 씌워진다. Subsequently, the metal shielding layer which is energized with the metal sheath 22 of the cable 100A is restored on the reinforcing insulating layer 210, and the spacer 250 and the protective copper tube 240 are covered.
상기 금속차폐층은 상기 제2 보강절연층의 슬로프부(2102B)와 직선부(2102A) 및 상기 접속함 외부반도전층(230)을 둘러싸도록 형성된다. The metal shielding layer is formed to surround the slope portion 2102B and the straight portion 2102A and the junction box outer semiconducting layer 230 of the second reinforcement insulating layer.
상기 제2 보강절연층의 슬로프부(2102B)를 둘러싸도록 형성되는 금속차폐층은 금속선재로 형성되는 것이 바람직하다. 상기 금속선재는 상기 금속선재는 동선, 연동선 내지 주석도금연동선 등일 수 있으며, 상기 슬로프부(2102B)를 둘러싸도록 상기 금속선재를 권취하거나 상기 금속선재로 이루어진 편조체를 감아 형성할 수 있다. 상기 슬로프부(2102B)는 기울기가 일정하지 않을 수 있는 슬로프 형상의 외면을 가지므로 상기 금속선재 내지 편조체를 사용하여 상기 접속함 외부반도전층(230)과 상기 금속차폐층을 원활히 통전시킬 수 있다. 또한, 상기 금속선재 사이 사이로 절연유가 침투할 수 있으므로 후술하는 절연유 함침이 용이한 장점이 있다.The metal shielding layer formed to surround the slope portion 2102B of the second reinforcement insulating layer is preferably formed of a metal wire. The metal wire may be a copper wire, a copper wire, a tin-plated copper wire, or the like, and may be formed by winding the metal wire to surround the slope portion 2102B or winding a braid made of the metal wire. Since the slope portion 2102B has a slope-shaped outer surface where the slope may not be constant, the junction outer semiconducting layer 230 and the metal shielding layer may be smoothly energized using the metal wire or braid. . In addition, since the insulating oil can penetrate between the metal wires, there is an advantage that the insulating oil impregnation to be described later is easy.
또한, 도 5에서와 같이 상기 중간접속함은 상기 제2 보강절연층의 직선부(2102A)를 둘러싸도록 형성되는 금속차폐층(250)을 포함할 수 있으며, 상기 금속차폐층(250)은 금속테이프 내지 금속판으로 이루어질 수 있다. 비교적 평활한 외면을 가지는 상기 제2 보강절연층의 직선부(2102B)에는 금속판을 종첨하여 접합하거나, 금속테이프를 권취함으로써 작업성을 향상시킬 수 있다. 다만, 후술하는 절연유 함침이 용이하도록 하기 위하여 상기 금속테이프 내지 금속판은 천공이 되어 있을 수 있다.In addition, as shown in FIG. 5, the intermediate junction box may include a metal shielding layer 250 formed to surround the straight portion 2102A of the second reinforcement insulating layer, and the metal shielding layer 250 may be formed of metal. It may be made of a tape to a metal plate. The workability can be improved by attaching a metal plate to the straight portion 2102B of the second reinforcement insulating layer having a relatively smooth outer surface or by winding a metal tape. However, the metal tape or the metal plate may be perforated to facilitate the impregnation of the insulating oil described later.
상기 스페이서는 내부에 관통공을 갖는 디스크 형상을 가지며, 알루미늄 등의 금속재질로 이루어질 수 있으며, 상기 제2 보강절연층의 직선부에 형성된다. 상기 스페이서는 상기 관통공을 통해 보강절연층(210) 외측에 끼워져서 후술하는 동관(240)과 상기 보강절연층(210) 사이의 간격을 유지시킬 수 있다. 특히, 스페이서(250)는 도 5에 도시된 바와 같이 외측면에는 반경방향으로 복수 개의 오목부(251)가 서로 이격되어 형성될 수 있다. 상기 오목부(251)를 통해 동관(240) 내의 절연유가 통과하게 된다. 즉 절연유 함침시 상기 동관(240)에 주입되는 절연유가 상기 오목부(251)를 통해 중간접속함(200)의 길이방향으로 원활히 이동할 수 있다. 또한, 절연유의 유동에 의해 상기 스페이서(250)가 움직이는 것을 방지하기 위해 상기 스페이서(250) 양측에 금속선재를 감아 고정시킬 수 있다. The spacer has a disk shape having a through hole therein, and may be made of a metal material such as aluminum, and formed on a straight portion of the second reinforcement insulating layer. The spacer may be inserted outside the reinforcing insulating layer 210 through the through hole to maintain a gap between the copper tube 240 to be described later and the reinforcing insulating layer 210. In particular, the spacer 250 may have a plurality of recesses 251 spaced apart from each other in the radial direction on the outer surface as shown in FIG. 5. The insulating oil in the copper tube 240 passes through the recess 251. That is, the insulating oil injected into the copper tube 240 when the insulating oil is impregnated can be smoothly moved in the longitudinal direction of the intermediate junction box 200 through the recess 251. In addition, in order to prevent the spacer 250 from moving by the flow of insulating oil, metal wires may be wound and fixed on both sides of the spacer 250.
상기 금속차폐층(260)과 스페이서(250) 사이에 금속차폐층 보호부(270)가 더 형성될 수 있다. 상기 금속차폐층 보호부(270)은 절연지를 상기 금속차폐층(260) 상에 권취하여 형성되며, 상기 스페이서(250)에 의해 금속차폐층(260)이 손상되는 것을 방지할 수 있다. 상세하게, 상기 스페이서(250)가 보강절연층(210) 외측에 끼워질 때 상기 보강절연층(210) 상에 형성된 금속차폐층(260)의 표면에 스크레치가 발생하거나, 중간접속함의 하중이 작용하여 스페이서(250)에 의해 금속차폐층(260)이 눌려 에지부가 발생할 수 있다. 이에 따라 스페이서(250)와 금속차페층 사이에 상기 금속차폐층 보호부(270)를 형성하여 스페이서(250)에 의한 금속차폐층(260)의 손상을 방지하고, 에지부 발생 등과 같은 표면 손상 및 이에 의한 전계집중을 방지할 수 있다.A metal shielding layer protection part 270 may be further formed between the metal shielding layer 260 and the spacer 250. The metal shielding layer protection unit 270 is formed by winding an insulating paper on the metal shielding layer 260, and may prevent the metal shielding layer 260 from being damaged by the spacer 250. In detail, when the spacer 250 is fitted to the outside of the reinforcing insulating layer 210, a scratch occurs on the surface of the metal shielding layer 260 formed on the reinforcing insulating layer 210, or a load of an intermediate junction box is applied. As a result, the metal shielding layer 260 may be pressed by the spacer 250 to generate an edge portion. Accordingly, the metal shielding layer protection part 270 is formed between the spacer 250 and the metal shielding layer to prevent the metal shielding layer 260 from being damaged by the spacer 250, and to prevent surface damage such as edge generation and the like. This can prevent electric field concentration.
이어서, 보호동관(240)이 씌워진다. 상기 보호동관(240)은 외부로부터 접속함 내부를 보호하고, 상기 케이블(100)의 금속시스(22)와 통전되어 사고 전류의 통로 역할을 할 수 있다.Subsequently, 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.
한편, 상기 중간접속 시스템은 상기 중간접속함에 절연유를 주유하여 절연성능을 담보할 필요가 있다. 구체적으로, 상기 보강절연층과 상기 보호동관 사이의 공간에 절연유를 충진하고, 특히, 반유침지를 권취하여 상기 보강절연층을 형성한 경우에는 상기 보강절연층을 절연유로 함침시켜 절연성능을 향상시킬 필요가 있다.On the other hand, the intermediate connection system needs to ensure insulating performance by lubricating insulating oil in the intermediate junction box. Specifically, when the insulating oil is filled in the space between the reinforcing insulating layer and the protective copper tube, and particularly when the reinforcing insulating layer is formed by winding anti-oil immersion, the reinforcing insulating layer is impregnated with the insulating oil to improve the insulating performance. There is a need.
본 발명의 상기 보호동관(240)은 절연유 유입관과 절연유 배출관을 구비할 수 있다. 상기 유입관 및 배출관은 상기 보호동관(240)의 외면에 서로 반대방향으로 형성되며, 절연유가 이동하는 통로역할을 한다.The protective copper tube 240 of the present invention may be provided with an insulating oil inlet pipe and an insulating oil discharge pipe. The inlet pipe and the discharge pipe are formed on the outer surface of the protective copper tube 240 in opposite directions, and serve as a passage through which the insulating oil moves.
상기 유입관을 통해 상기 보호동관 내부로 공급되는 절연유가 상기 접속함 외부반도전층 및 금속차폐층을 통해 보강절연층(210)을 함침시키면서 상부의 배출관을 통해 외부로 배출된다. 또한, 질소 가스 등을 이용하여 상기 절연유를 가압함으로써, 보강절연층이 원활히 함침되도록 하여 절연성능을 향상시킬 수 있다.The insulating oil supplied into the protective copper tube through the inlet pipe is discharged to the outside through the upper discharge pipe while impregnating the reinforcing insulating layer 210 through the junction box outer semiconducting layer and the metal shielding layer. In addition, by pressurizing the insulating oil using nitrogen gas or the like, the reinforcement insulating layer may be smoothly impregnated to improve the insulating performance.
이상의 설명은 본 발명의 기술 사상을 예시적으로 설명한 것에 불과한 것으로서, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자라면 본 발명의 본질적인 특성에서 벗어나지 않는 범위에서 다양한 수정 및 변형이 가능할 것이다.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.
따라서, 본 발명에 개시된 실시 예들은 본 발명의 기술 사상을 한정하기 위한 것이 아니라 설명하기 위한 것이고, 이러한 실시 예에 의하여 본 발명의 기술 사상의 범위가 한정되는 것은 아니다.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.
본 발명의 보호 범위는 아래의 청구범위에 의하여 해석되어야 하며, 그와 동등한 범위 내에 있는 모든 기술 사상은 본 발명의 권리범위에 포함되는 것으로 해석되어야 할 것이다. 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 (23)

  1. 도체, 내부반도전층, 케이블 절연층 및 외부반도전층을 구비하는 한 쌍의 직류 전력케이블과 상기 한 쌍의 직류 전력케이블을 서로 연결시키는 중간접속함을 포함하는 직류 전력케이블 중간접속 시스템에 있어서,A DC power cable intermediate connection system comprising a pair of DC power cables having a conductor, an inner semiconducting layer, a cable insulation layer, and an outer semiconducting layer and an intermediate junction box connecting the pair of DC power cables to each other.
    상기 한 쌍의 직류 전력케이블은 상기 도체, 내부반도전층, 케이블 절연층 및 외부반도전층이 순차적으로 노출된 각 단부가 서로 대향하도록 구비되고,The pair of DC power cables are provided such that the ends of the conductor, the inner semiconducting layer, the cable insulation layer, and the outer semiconducting layer sequentially expose each other.
    상기 중간접속함은,The intermediate junction box,
    상기 노출된 한 쌍의 도체를 전기적, 기계적으로 연결하는 도체 접속부;A conductor connecting portion for electrically and mechanically connecting the exposed pair of conductors;
    상기 도체 접속부, 상기 노출된 내부반도전층 및 케이블 절연층을 둘러싸도록 절연지가 권취되어 상기 케이블 절연층 외경까지 형성되고, 길이방향에서의 양 단부에 경사면을 갖는 제1 보강절연층과, 상기 제1 보강절연층 및 상기 노출된 케이블 절연층을 둘러싸며 상기 케이블 길이방향으로의 폭이 일정한 직선부와 상기 직선부의 양단에 형성되며 상기 케이블 길이방향으로의 폭이 상기 케이블의 방사방향으로 감소하는 슬로프부를 구비한 제2 보강절연층을 포함하는 보강절연층; 및A first reinforcing insulating layer wound around the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer, and formed up to an outer diameter of the cable insulating layer, and having a sloped surface at both ends in the longitudinal direction, and the first reinforcing layer A straight line portion surrounding the exposed insulation layer and the exposed cable insulation layer and having a constant width in the longitudinal direction of the cable and a slope portion having a width in the longitudinal direction of the cable reduced in the radial direction of the cable are formed at both ends. A reinforcing insulating layer including a second reinforcing insulating layer provided; And
    상기 제2 보강절연층의 슬로프부의 외측면을 따라 형성되어 그 자체로 슬로프 형상을 가지며, 반도전성 재질로 이루어진 접속함 외부반도전층을 구비하며,It is formed along the outer surface of the slope portion of the second reinforcing insulating layer and has a slope shape by itself, provided with a junction box outer semiconductive layer made of a semiconductive material,
    상기 제1 보강절연층과 상기 케이블 절연층 사이의 계면은 단일 경사면으로 이루어지고,The interface between the first reinforcing insulation layer and the cable insulation layer is made of a single sloped surface,
    상기 제2 보강절연층은 상기 제1 보강절연층 상에 적층되는 복수 개의 절연지층으로 이루어지며, The second reinforcement insulating layer is formed of a plurality of insulating paper layers stacked on the first reinforcement insulating layer,
    상기 절연지층 각각은 세폭지가 지권되어 형성되는 적어도 하나의 세폭지 권취부 및 상기 세폭지 보다 폭이 더 넓은 광폭지가 지권되어 형성되는 광폭지 권취부로 이루어지고, Each of the insulating paper layers may include at least one narrow paper winding part formed by narrow paper and wide paper winding part formed by wide paper being wider than the narrow paper.
    상기 제1 보강절연층에 권취된 절연지는 그 폭이 상기 제2 보강절연층의 세폭지 권취부를 형성하는 절연지의 폭보다는 크고, 보강절연층의 광폭지 권취부를 형성하는 절연지의 폭보다는 작은 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.The insulating paper wound on the first reinforcing insulating layer has a width larger than that of the insulating paper forming the narrow paper winding of the second reinforcing insulating layer and smaller than the width of the insulating paper forming the wide paper winding of the reinforcing insulating layer. DC power cable intermediate connection system.
  2. 제1항에 있어서, The method of claim 1,
    상기 제1 보강절연층에 지권된 절연지 층수는 상기 케이블 절연층에 지권된 절연지 층수의 80% 이상인 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.And the number of insulating paper layers supported on the first reinforcement insulating layer is 80% or more of the number of insulating paper layers supported on the cable insulating layer.
  3. 제1항에 있어서, The method of claim 1,
    상기 제2 보강절연층에서의 어느 한 절연지층의 세폭지 권취부는 상기 절연지층에 인접한 절연지층의 세폭지 권취부와 소정의 거리만큼 이격되어 배치되는 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.And the narrow paper winding part of the insulating paper layer in the second reinforcing insulating layer is spaced apart from the narrow paper winding part of the insulating paper layer adjacent to the insulating paper layer by a predetermined distance.
  4. 제1항에 있어서, The method of claim 1,
    상기 제2 보강절연층에서의 어느 한 절연지층의 세폭지 권취부는 상기 절연지층 상에 접하여 위치하거나 아래 접하여 위치하는 다른 절연지층의 세폭지 권취부와 상하 방향에서 서로 중첩되지 않는 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.The narrow paper winding portion of one of the insulating paper layers in the second reinforcement insulating layer is characterized in that the direct current does not overlap with the narrow paper winding portion of the other insulating paper layer positioned on or in contact with the insulating paper layer in the vertical direction. Power cable intermediate connection system.
  5. 제1항에 있어서, The method of claim 1,
    상기 제2 보강절연층에서의 어느 한 절연지층의 세폭지 권취부에서 상기 절연지층 상에 접하여 위치하거나 아래 접하여 위치하는 다른 절연지층의 세폭지 권취부까지의 이격된 거리는, 상기 절연지층에 접하는 절연지층 내에서 서로 인접한 광폭지 권취부들이 접하여 형성되는 맞대기부와 상기 절연지층의 세폭지 권취부 사이의 최단 거리보다 크거나 같은 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.The distance from the narrow paper winding of one insulating paper layer in the second reinforcing insulating layer to the narrow paper winding portion of another insulating paper layer which is in contact with or below the insulating paper layer is insulated in contact with the insulating paper layer. A DC power cable intermediate connection system, characterized in that it is greater than or equal to the shortest distance between the butt portion formed by the adjacent wide winding portions in the strata and the narrow winding portion of the insulating layer.
  6. 제1항에 있어서, The method of claim 1,
    상기 세폭지 권취부는 상기 슬로프부에는 위치하지 않고 상기 직선부에 위치하는 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.And the narrow paper winding part is located not in the slope part but in the straight part.
  7. 제1항에 있어서, The method of claim 1,
    상기 슬로프부는 상기 광폭지 권취부로 이루어지는 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.And said slope portion comprises said wide paper winding portion.
  8. 제1항에 있어서, The method of claim 1,
    상기 중간접속함은The intermediate junction box
    상기 접속함 외부반도전층 상에 형성되는 금속차폐층; A metal shielding layer formed on the junction box outer semiconducting layer;
    상기 보강절연층 및 상기 전력 케이블의 일부를 감싸며 그 내부에 절연유를 포함하는 동관; 및A copper tube surrounding the reinforcement insulating layer and a part of the power cable and including insulating oil therein; And
    상기 동관과 상기 금속차폐층 사이의 간격을 유지시키는 스페이서; 를 포함하는 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.A spacer for maintaining a gap between the copper tube and the metal shielding layer; DC power cable intermediate connection system comprising a.
  9. 제1항에 있어서, The method of claim 1,
    상기 도체접속부는,The conductor connecting portion,
    사선으로 절단되어 단부가 서로 대향하도록 구비된 한 쌍의 도체; 및A pair of conductors which are cut in diagonal lines so that the ends thereof face each other; And
    상기 도체의 단부 사이에 형성된 필러금속을 포함하는 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.DC power cable intermediate connection system comprising a filler metal formed between the ends of the conductor.
  10. 제1항에 있어서, The method of claim 1,
    상기 도체접속부는,The conductor connecting portion,
    상기 케이블에서 노출되어 단부가 서로 대향하도록 구비된 한 쌍의 도체; 및A pair of conductors exposed from the cable and provided with their ends facing each other; And
    상기 한 쌍의 도체 단부를 둘러싸는 도체 압착슬리브;를 구비하며,And a conductor crimp sleeve surrounding the pair of conductor ends,
    상기 도체 압착슬리브는 외경이 상기 도체의 외경이 동일한 것을 특징으로 하는 직류 전력케이블 중간접속 시스템.The conductor crimp sleeve has an outer diameter equal to the outer diameter of the conductor, DC power cable intermediate connection system.
  11. 도체, 내부반도전층, 케이블 절연층 및 외부반도전층을 구비하며, 상기 도체, 내부반도전층, 케이블 절연층 및 외부반도전층이 순차적으로 노출된 각 단부가 대향하도록 구비된 한 쌍의 직류 전력 케이블을 서로 접속하는 방법에 있어서,A pair of DC power cables including a conductor, an inner semiconducting layer, a cable insulation layer, and an outer semiconducting layer, the ends of which the conductor, the inner semiconducting layer, the cable insulation layer, and the outer semiconducting layer are sequentially exposed. In the method of connecting to each other,
    상기 노출된 한 쌍의 도체를 서로 전기적, 기계적으로 연결하여 도체 접속부를 형성하는 단계;Forming a conductor connection by electrically and mechanically connecting the exposed pair of conductors to each other;
    상기 도체 접속부, 상기 노출된 내부반도전층 및 케이블 절연층을 둘러싸도록 절연지를 상기 케이블 절연층 외경까지 권취하여 제1 보강절연층을 형성하는 단계;Forming a first reinforcing insulating layer by winding insulating paper to the outer diameter of the cable insulating layer so as to surround the conductor connecting portion, the exposed inner semiconducting layer and the cable insulating layer;
    상기 제1 보강절연층 및 상기 노출된 케이블 절연층을 둘러싸도록 절연지를 권취하여 제2 보강절연층을 형성하는 단계; 및Forming a second reinforcing insulating layer by winding insulating paper to surround the first reinforcing insulating layer and the exposed cable insulating layer; And
    상기 제2 보강절연층의 외면을 둘러싸는 접속함 외부반도전층을 형성하는 단계;를 구비하며,And forming a junction box outer semiconducting layer surrounding an outer surface of the second reinforcing insulating layer.
    상기 제2 보강절연층을 형성하는 단계는 상기 제1 보강절연층 상에 세폭지 권취부 및 상기 세폭지 권취부를 이루는 절연지보다 폭이 큰 절연지로 이루어진 광폭지 권취부를 포함하는 절연지층을 복수개 적층하는 단계를 포함하고, The forming of the second reinforcement insulating layer may include stacking a plurality of insulating paper layers including a wide paper winding portion formed of a narrow paper winding portion and an insulating paper having a width larger than that of the insulating paper forming the narrow paper winding portion on the first reinforcing insulating layer. Including steps
    상기 제1 보강절연층을 형성하는 단계는,Forming the first reinforcement insulating layer,
    상기 노출된 케이블 절연층의 단부 형상에 대응하도록 상기 제1 보강절연층 단부에 단일 경사면을 형성하는 단계와, 상기 세폭지 권취부의 절연지보다 폭이 크고 보다 크고, 광폭지 권취부의 절연지보다 폭이 작은 절연지를 권취하는 단계를 포함하는 것을 특징으로 하는 직류 전력케이블 접속 방법.Forming a single inclined surface at the end of the first reinforcing insulating layer to correspond to the end shape of the exposed cable insulating layer, and having a width larger and larger than that of the narrow paper winding portion, and wider than the insulating paper of the wide paper winding portion. DC power cable connection method comprising the step of winding the small insulating paper.
  12. 제 11항에 있어서, The method of claim 11,
    상기 제1 보강절연층을 형성하는 단계는Forming the first reinforcement insulating layer is
    상기 절연지는 반유침지이며,The insulating paper is semi-oil immersed,
    상기 케이블 절연층에 권취된 절연지의 층수의 80% 이상 상기 반유침지를 권취하는 것을 특징으로 하는 직류 전력케이블 접속 방법.A method for connecting a direct current power cable, characterized in that the semi-impregnated paper is wound at least 80% of the number of layers of the insulating paper wound on the cable insulation layer.
  13. 제11항에 있어서, The method of claim 11,
    상기 제2 보강절연층을 형성하는 단계는,Forming the second reinforcement insulating layer,
    상기 제2 보강절연층의 어느 한 절연지층의 세폭지 권취부를 상기 절연지층에 인접한 절연지층의 세폭지 권취부와 소정의 거리만큼 이격시켜 배치하는 것을 특징으로 하는 직류 전력케이블 접속 방법.And the narrow paper winding portion of one of the insulating paper layers of the second reinforcing insulating layer is spaced apart from the narrow paper winding portion of the insulating paper layer adjacent to the insulating paper layer by a predetermined distance.
  14. 제11항에 있어서, The method of claim 11,
    상기 제2 보강절연층을 형성하는 단계는,Forming the second reinforcement insulating layer,
    상기 제2 보강절연층의 어느 한 절연지층의 세폭지 권취부를 상기 절연지층에 접하여 위치하는 다른 절연지층의 세폭지 권취부와 서로 중첩되지 않도록 배치하는 것을 특징으로 하는 직류 전력케이블 접속 방법.And a narrow paper winding portion of one of the insulating paper layers of the second reinforcing insulating layer so as not to overlap with the narrow paper winding portion of another insulating paper layer positioned in contact with the insulating paper layer.
  15. 제11항에 있어서, The method of claim 11,
    상기 제2 보강절연층을 형성하는 단계는,Forming the second reinforcement insulating layer,
    상기 제2 보강절연층의 어느 한 절연지층의 세폭지 권취부를 상기 절연지층 상에 접하여 위치하거나 아래 접하여 위치하는 다른 절연지층의 세폭지 권취부까지의 이격된 거리는, 상기 절연지층에 접하는 절연지층 내에서 서로 인접한 광폭지 권취부들이 접하여 형성되는 맞대기부와 상기 절연지층의 세폭지 권취부 사이의 최단 거리보다 크거나 같도록 배치하는 것을 특징으로 하는 직류 전력케이블 접속 방법.The spaced distance to the narrow paper winding portion of the other insulating paper layer positioned in contact with or below the narrow paper winding portion of the insulating paper layer of the second reinforcement insulating layer is in the insulating paper layer in contact with the insulating paper layer. DC power cable connection method characterized in that arranged so that the width of the butt portion formed adjacent to each other adjacent to each other in contact with each other and the shortest distance between the narrow paper winding portion of the insulating paper layer.
  16. 제11항에 있어서, The method of claim 11,
    상기 제2 보강절연층을 형성하는 단계는,Forming the second reinforcement insulating layer,
    상기 슬로프부에는 상기 세폭지 권취부를 배치하지 않는 것을 특징으로 하는 직류 전력케이블 접속 방법.And the narrow paper winding portion is not disposed on the slope portion.
  17. 제11항에 있어서, The method of claim 11,
    상기 제2 보강절연층을 형성하는 단계는,Forming the second reinforcement insulating layer,
    상기 슬로프부에 상기 광폭지 권취부만을 배치하는 것을 특징으로 하는 직류 전력케이블 접속 방법.DC power cable connection method characterized in that only the wide winding portion is disposed in the slope portion.
  18. 제11항에 있어서, The method of claim 11,
    상기 접속함 외부반도전층을 둘러싸도록 금속차폐층을 형성하는 단계;Forming a metal shielding layer to surround the junction box outer semiconducting layer;
    상기 제2 보강절연층의 직선부의 일부를 둘러싸도록 스페이서를 형성하는 단계;Forming a spacer to surround a portion of the straight portion of the second reinforcement insulating layer;
    상기 보강절연층 및 상기 전력 케이블의 일부를 감싸는 동관을 설치하는 단계; 및Installing a copper tube surrounding the reinforcement insulating layer and a part of the power cable; And
    상기 동관에 절연유를 주입하고 가압하여 상기 보강절연층의 절연지를 함침시키는 단계를 포함하는 것을 특징으로 하는 직류 전력케이블 접속 방법.Injecting and pressurizing insulating oil into the copper pipe to impregnate the insulating paper of the reinforcing insulating layer.
  19. 제18항에 있어서, The method of claim 18,
    상기 금속차폐층을 형성하는 단계는,Forming the metal shielding layer,
    금속선재가 상기 제2 보강절연층의 슬로프부를 둘러싸도록 권취하며, 천공된 금속판이 상기 제2 보강절연층의 직선부를 둘러싸도록 형성하는 단계를 포함하는 것을 특징으로 하는 직류 전력케이블 접속 방법.And winding a metal wire to surround the slope portion of the second reinforcement insulating layer, and forming the perforated metal plate to surround the straight portion of the second reinforcement insulating layer.
  20. 제19항에 있어서, The method of claim 19,
    상기 금속차폐층을 형성하는 단계는,Forming the metal shielding layer,
    상기 천공된 금속판이 상기 직선부를 둘러싸도록 종첨하고 접합하는 것을 특징으로 하는 직류 전력케이블 접속 방법.And the perforated metal plate is terminated and joined to surround the straight portion.
  21. 제18항에 있어서, The method of claim 18,
    상기 스페이서를 형성하는 단계는,Forming the spacers,
    내부에 상기 제2 보강절연층의 외경보다 더 큰 내경을 갖는 관통공과, 그 외측부에는 상기 관통공을 향하는 오목부를 포함하며, 상기 오목부를 통해 상기 동관 내의 상기 절연유가 상기 중간접속함의 길이 방향으로 유동할 수 있는 것을 특징으로 하는 스페이서를 상기 제2 보강절연층의 직선부에 배치하는 것을 특징으로 하는 직류 전력케이블 접속 방법.A through hole having an inner diameter larger than an outer diameter of the second reinforcing insulating layer therein, and an outer portion thereof having a recess facing the through hole, through which the insulating oil in the copper tube flows in the longitudinal direction of the intermediate junction box. And a spacer arranged in a straight portion of the second reinforcement insulating layer.
  22. 제11항에 있어서,The method of claim 11,
    상기 도체 접속부를 형성하는 단계는,Forming the conductor connecting portion,
    상기 케이블에서 노출되어 단부가 서로 대향하도록 구비된 한 쌍의 도체 단부 사이에 필러금속을 충진하는 것을 특징으로 하는 직류 전력케이블 접속 방법.The method of connecting a DC power cable, characterized in that the filler metal is filled between a pair of conductor ends exposed from the cable so that the ends thereof face each other.
  23. 제11항에 있어서, The method of claim 11,
    상기 도체 접속부를 형성하는 단계는,Forming the conductor connecting portion,
    상기 케이블에서 노출되어 단부가 서로 대향하도록 구비된 한 쌍의 도체의 각 단부를 둘러싸도록 도체 압착슬리브 배치하고, 상기 도체압착슬리브의 외면을 압착하며, 상기 도체압착슬리브의 외경과 상기 도체의 외경이 동일하도록 형성하는 것을 특징으로 하는 직류 전력케이블 중간접속 방법.Conductor crimp sleeves are disposed so as to surround each end of the pair of conductors exposed from the cable so that the end faces each other, the outer surface of the conductor crimp sleeve is crimped, and the outer diameter of the conductor crimp sleeve and the outer diameter of the conductor are DC power cable intermediate connection method characterized in that formed to be the same.
PCT/KR2017/003604 2017-03-30 2017-03-31 Direct current power cable joining system using joint box for power cable and direct current power cable joint method WO2018182076A1 (en)

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JP2005353379A (en) * 2004-06-09 2005-12-22 Sumitomo Electric Ind Ltd Intermediate connection structure of superconductive cable
JP2006196418A (en) * 2005-01-17 2006-07-27 Sumitomo Electric Ind Ltd Electric wire workpiece and its manufacturing method
WO2013157513A1 (en) * 2012-04-19 2013-10-24 古河電気工業株式会社 Connection structure for superconducting cable
KR20150106639A (en) * 2014-03-12 2015-09-22 엘에스전선 주식회사 Termination connection box
KR20160084920A (en) * 2015-01-06 2016-07-15 엘에스전선 주식회사 Joint box

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* Cited by examiner, † Cited by third party
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JP2005353379A (en) * 2004-06-09 2005-12-22 Sumitomo Electric Ind Ltd Intermediate connection structure of superconductive cable
JP2006196418A (en) * 2005-01-17 2006-07-27 Sumitomo Electric Ind Ltd Electric wire workpiece and its manufacturing method
WO2013157513A1 (en) * 2012-04-19 2013-10-24 古河電気工業株式会社 Connection structure for superconducting cable
KR20150106639A (en) * 2014-03-12 2015-09-22 엘에스전선 주식회사 Termination connection box
KR20160084920A (en) * 2015-01-06 2016-07-15 엘에스전선 주식회사 Joint box

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