Submarine cable

Abstract

The present invention relates to a submarine wherein the shapes of multiple shape-maintaining fillers, which surround multiple power units constituting the submarine while keeping the multiple power units spaced apart from each other, can be modified to prevent damage to metal shielding layers constituting the power units under conditions where the submarine cable is installed underwater and subject to repeated bending and flexing. The present invention may provide a submarine cable for underwater installation, the submarine cable comprising: a conductor; multiple power units, each of which comprises an insulating layer surrounding the conductor, and a metal shielding layer surrounding the insulating layer; multiple shape-maintaining fillers that keep the multiple power units spaced apart from each other and enable the submarine cable to have a circular cross-section; and a cable protection layer provided outside the multiple shape-maintaining fillers, wherein at least one of both circumferential ends of each of the shape-maintaining fillers has a surface which is in contact with a circumferential end of an adjacent shape-maintaining filler.

Description

submarine cables

[0001] The present invention relates to a submarine cable. More specifically, the present invention relates to a submarine cable capable of preventing damage to the metal shielding layer constituting the power units in an environment where the cable is laid underwater and repeatedly bends and flexes by changing the shape of a plurality of shape fillers that maintain the plurality of power units constituting the submarine cable in a mutually spaced state.

[0002] Recently, renewable energy systems that install wind turbines and other devices in the sea at a certain distance from land with sufficient wind power and supply the generated electricity by connecting it to onshore power facilities via power cables have been gaining attention.

[0003] In cases where the sea depth is shallow, wind turbines can be installed on top of a structure built on the seabed. However, in cases where the sea depth is deep, wind turbines can be installed in a floating manner.

[0004] Floating wind turbines and substations are supported by floating materials and float above the sea surface, and the floating materials can be connected to anchors installed on the seabed with support lines to restrict their movement.

[0005] In addition, wind turbines installed at sea or substations connecting the wind turbines and power facilities on land can be connected by submarine cables laid underwater.

[0006] Here, the section from the ground-based power facilities to the seabed near the offshore wind turbine is the section where the submarine cable is laid on the seabed, and since no movement of the cable occurs while transmitting power after the cable is laid, this section is called a static section, and the submarine cable laid in this section is generally called a static submarine cable. On the other hand, the section from the seabed near the wind turbine to the floating wind turbine or substation is subject to a lot of movement of the cable due to ocean currents, waves, etc., so this section is called a dynamic section, and the submarine cable laid in this section is called a dynamic submarine cable.

[0007] Dynamic submarine cables installed in dynamic sections are subjected to long-term, repetitive bending loads due to movement or bending caused by ocean currents or waves. It is difficult to apply a lead-skin shield layer as a metal shield layer that cannot withstand such environments to dynamic submarine cables.

[0008] Therefore, instead of a sheath shield layer, a dynamic submarine cable forms a shield wire layer by spirally winding multiple metal wires spaced apart on top of a bedding layer, and the outer side is wound with a metal tape to conduct current throughout the metal wire layer, thereby forming a metal shield layer.

[0009] In addition, the dynamic submarine cable may be equipped with multiple power units, and the empty spaces between the multiple power units may be filled with multiple spaced shape fillers to form a circular cross-section of the cable, and a cable protection layer may be provided on the outside of the power units and the shape fillers. Accordingly, the cable protection layer alternately wraps around the power units and the shape fillers in a circumferential direction to protect the submarine cable.

[0010] However, the metal tape that is wound horizontally on the outside of the shielding wire that constitutes the metal shielding layer may be made of, for example, a copper tape. The metal shielding layer of this structure may be strongly pressed by the cable protection layer having an armor wire or the like when the submarine cable is repeatedly bent or bent, causing the shielding wire that constitutes the metal shielding layer to be short-circuited or twisted, or the metal tape to be broken. As a result, the metal shielding layer may deteriorate the current-carrying and shielding functions of the fault current.

[0011] The present invention relates to a submarine cable capable of preventing damage to a metal shielding layer constituting a power unit in an environment where bending and flexing occur repeatedly while being laid underwater by changing the shape of a plurality of shape fillers that maintain a plurality of power units constituting the submarine cable in a mutually spaced state.

[0012] In order to solve the above problem, the present invention provides a submarine cable for underwater installation, comprising: a plurality of power units including a conductor, an insulation layer covering the conductor, and a metal shielding layer covering the insulation layer; a plurality of shape fillers that maintain the plurality of power units in a mutually spaced state and make the submarine cable have a circular cross-section; and a cable protection layer provided on the outer side of the plurality of shape fillers; wherein at least one end of each of the circumferential ends of the shape fillers has a surface that contacts the circumferential end of an adjacent shape filler.

[0013] Additionally, the radius of the arc formed by the inner surface of the shape fillers that come into contact with the surface may be larger than the diameter of the power unit.

[0014] In addition, each of the above shape fillers may be additionally provided with a fixing means that is mutually interlocked and fixed to the ends of the shape fillers adjacent to the circumferential ends.

[0015] In addition, the fixing means is configured with a hook provided at one end of each of the two ends of the shape filler and a hook groove in which the hook is received at the other end, so that a hook provided at one end of one of the two adjacent shape fillers can be hooked and fixed to a hook groove provided at the other end of the other shape filler.

[0016] In this case, the catch and catch groove provided in the shape filler may be provided to extend along the length of the power unit.

[0017] In this case, the stumbling block may be configured in a shape that extends from the side of the shape filler and expands in width outward.

[0018] Here, an optical unit receiving portion for receiving an optical unit having at least one optical fiber inside the shape filler may be provided.

[0019] Additionally, an inlet may be formed at the inner end of the shape filler through which a light unit can be inserted.

[0020] In addition, the power unit and the shape filler are each provided in three units, and each of the shape fillers is provided with two inner surfaces in a curved shape, and a pair of adjacent shape fillers are in surface contact with each other so that the inner surfaces form one circular arc, and a placement space in which one power unit is placed can be formed inside the one circular arc.

[0021] In addition, a center pillar having a plurality of concave outer surfaces for supporting a plurality of power units may be additionally provided at the center of the submarine cable.

[0022] In this case, each of the inner ends of the shape filler and the plurality of outer ends of the center filler can be in surface contact.

[0023] Here, a binding tape layer may further be included that wraps a plurality of the above shape fillers.

[0024] Additionally, the cable protection layer may include a bedding layer provided on the outside of the binding tape layer, at least one armor wire layer provided on the outside of the bedding layer, and an outermost layer provided on the outside of the armor wire layer.

[0025] According to the submarine cable according to the present invention, a plurality of power units are kept in a mutually spaced state, and the ends of adjacent shape fillers among a plurality of shape fillers that form a circular cross-sectional shape of the submarine cable are in surface contact, so that damage to the metal shielding layer of the power unit can be minimized by the cable protection layer including an armor layer composed of armor wires on the outside of the shape fillers when the submarine cable is bent or bent underwater.

[0026] In addition, each shape filler is provided at a predetermined interval from each of the plurality of power units, so that damage to the metal shielding layer of the power unit caused by the cable protection layer including the armor layer composed of the armor wire on the outside of the shape filler when the submarine cable is bent or bent underwater can be further minimized.

[0027] In addition, according to the submarine cable according to the present invention, a center filler is additionally provided at the center of a plurality of power units to prevent movement of the power units toward the center of the submarine cable, thereby further minimizing damage to the metal shielding layer of the power units.

[0028] In addition, according to the submarine cable according to the present invention, since a catch is formed at one end of each shape filler in the circumferential or widthwise direction and a catch groove for receiving the catch is additionally formed at the other end, the shape fillers are mutually caught and fixed, so that even if bending or bending of the submarine cable occurs significantly, the support state of the shape fillers is stably maintained, thereby preventing the opening or slipping between the shape fillers, and thus further minimizing damage to the metal shielding layer of the power unit.

[0029] Figure 1 illustrates an example of the configuration of an offshore wind power generation system connected to a submarine cable according to the present invention.

[0030] Figure 2 illustrates a multi-stage stripped perspective view of a dynamic submarine cable for underwater installation according to the present invention.

[0031] Figure 3 shows a cross-sectional view of one embodiment of a submarine cable (100) according to the present invention.

[0032] Figure 4 shows a cross-sectional view of another embodiment of a submarine cable (100) according to the present invention.

[0033] Figure 5 shows a cross-sectional view of another embodiment of a submarine cable (100) according to the present invention.

[0034] Figure 6 shows a cross-sectional view of another embodiment of a submarine cable (100) according to the present invention.

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosure is thorough and complete, and to sufficiently convey the spirit of the invention to those skilled in the art. Like reference numbers designate like elements throughout the specification.

[0036] Figure 1 illustrates an example of the configuration of an offshore wind power generation system connected to a submarine cable (100) according to the present invention.

[0037] The installation of wind turbines (WB) is increasing in remote areas of the sea where there is sufficient wind and a certain distance from land.

[0038] In order to achieve abundant and consistent wind speeds, wind turbines (WB) are often installed in relatively deep seas rather than coastal areas. In the case of wind turbines installed in shallow coastal areas, they are installed on top of structures erected on the seabed. However, in deep seas, it is often impossible to install structures on the seabed. Therefore, wind turbines (WB) are installed in a floating manner, anchored (A) on the seabed, and moored by connecting the wind turbine (WB) with a fixed wire (R).

[0039] In addition, when an offshore wind power generator (wb) is configured as a standalone power generation complex, multiple wind power generators (wb) are installed to form a larger power generation complex, and the power generated by multiple wind power generators (wb) is combined and supplied to a power facility (ps) on land in a form that minimizes power loss through a substation (ts), etc.

[0040] In this case, the onshore power facility (ps) and the offshore substation facility (ts) can be connected through a submarine cable system (1000).

[0041] The submarine cable constituting the submarine cable system (1000) illustrated in Fig. 1 is connected to a power facility (ps) on land and laid on the seabed up to the vicinity of a substation facility on the seabed. However, in order to connect to a substation facility (ts) on the seabed near the substation facility, an underwater laying is required.

[0042] Here, the submarine cable (300) installed on the seabed is generally buried in the seabed or covered with a protective material, whereas the submarine cable (100) in the section from the seabed to the sea surface is exposed underwater and is affected by various external forces such as currents and waves. The installation of the submarine cable from the seabed to the sea surface is called underwater installation. In addition, the submarine cable can be connected to substation facilities installed above the sea surface, and the section above the sea surface can also be treated as an underwater installation section.

[0043] Accordingly, a submarine cable system (1000) for connecting a land-based power facility (ps) and a sea-based substation facility (ts) may be installed in some sections on the seabed (g) and in other sections underwater (w).

[0044] In the case of a submarine cable system (1000), it is desirable to configure cable protection layers differently for sections installed on the seabed (g) and sections installed underwater (w) due to differences in their respective environments. The underwater (w) section is a section where the cable is continuously affected by waves or currents, and thus requires reinforcement of the cable protection layer compared to the cable installed on the seabed (g).

[0045] Depending on the differences in cable protection layers, the submarine cable system (1000) can be classified into a dynamic submarine cable (100) and a static submarine cable (300), and can have a structure in which different cable protection layers are connected at an intermediate connection (200).

[0046] The submarine cable below may mean a dynamic submarine cable (100).

[0047] Figure 2 illustrates a multi-stage stripped perspective view of a dynamic submarine cable for underwater installation according to the present invention.

[0048] A submarine cable (100) according to an embodiment of the present invention may include a cable core portion including one or more power units (10) for power transmission and a cable protection layer surrounding the outer side of the cable core portion. The cable core portion may include three power units (10), an optical unit (20), and a shape filler (30), and the cable protection layer may include a bedding layer (70), an armor layer (80), and an outermost layer (110). A detailed description of each component will be provided below.

[0049] In the embodiment of the present invention, a three-phase cable having three power units (10) is illustrated as an example, but the present invention is not limited thereto and can be applied to cases where one power unit (10) is provided or the number of power units (10) is different.

[0050] Each of the above power units (10) may be configured to include a conductor (11), an inner semiconducting layer (12), an insulating layer (13), an outer semiconducting layer (14), a metal shielding layer (15), and a polymer sheath (16).

[0051] The conductor (11) above serves as a passage through which current flows to transmit power, and may be made of a material having excellent conductivity and strength and flexibility suitable for cable manufacturing and use, such as copper or aluminum, to minimize power loss.

[0052] The conductor (11) above may be a bundle conductor formed by stranding a plurality of circular wires and gathering them into a circle, as illustrated in FIG. 2, and specifically, may be a bundle conductor formed by stranding a plurality of circular wires in an S direction or a Z direction, and further may be a flat conductor having an overall circular cross-section, including a flat wire layer formed by stranding a circular central wire and a flat wire to surround the circular central wire. In the case where the conductor is formed of the latter flat conductor, there is an advantage in that the outer diameter of the cable can be reduced because the space factor is relatively high compared to a circular compressed conductor.

[0053] However, the surface of the conductor (11) is not smooth, so the electric field may be uneven, and corona discharge may easily occur partially. In addition, if a gap is created between the surface of the conductor (11) and the insulating layer (13) described later, the insulating performance may be deteriorated.

[0054] In order to solve the above problem, an internal semiconducting layer (12) may be provided on the outside of the conductor (11). The internal semiconducting layer (12) may have semiconductivity by adding conductive particles such as carbon black, carbon nanotubes, carbon nanoplates, and graphite to an insulating material.

[0055] The above inner semiconducting layer (12) functions to stabilize the insulation performance by preventing a sudden change in electric field between the conductor (11) and the insulating layer (13) described below. In addition, it suppresses uneven charge distribution on the conductor surface to make the electric field uniform, and prevents the formation of a gap between the conductor (11) and the insulating layer (13), thereby suppressing corona discharge, insulation breakdown, etc.

[0056] The above insulating layer (13) is provided on the outside of the inner semiconducting layer (12) to electrically insulate the current flowing along the conductor (11) from the outside so that it does not leak to the outside. In general, the insulating layer (13) must have a high breakdown voltage and must be able to maintain its insulating performance stably for a long period of time. Furthermore, it must have a low dielectric loss and have heat resistance performance such as heat resistance. Therefore, the insulating layer (13) can use a polyolefin resin such as polyethylene and polypropylene, and the polyethylene resin can be made of a crosslinked paper.

[0057] An external semiconducting layer (14) may be provided on the outside of the insulating layer (13). The external semiconducting layer (14) is formed of a semiconducting material by adding conductive particles, such as carbon black, carbon nanotubes, carbon nanoplates, graphite, etc., to an insulating material like the internal semiconducting layer (12), thereby suppressing uneven charge distribution between the insulating layer (13) and a metal shielding layer (15) described below, thereby stabilizing the insulating performance. In addition, the external semiconducting layer (14) may perform the function of smoothing the surface of the insulating layer (13) in the cable, alleviating electric field concentration, preventing corona discharge, and physically protecting the insulating layer (13).

[0058] A metal shielding layer (15) and a polymer sheath (16) may be provided on the outside of the external semiconducting layer (14). The metal shielding layer (15) and the polymer sheath (16) can protect the power unit (10) from various environmental factors such as moisture penetration, mechanical trauma, and corrosion that may affect the power transmission performance of the cable.

[0059] The above metal shielding layer (15) not only protects the power unit (10) from external impact, but also acts as a passage for the fault current to flow in the event of an accident such as a ground fault or short circuit by being grounded at the end of the power unit (10), thereby shielding the electric field from being discharged to the outside of the power unit (10).

[0060] Typically, a lead sheath is used as the metal shielding layer (15), or a shielding wire and a metal tape can be used. In the case of a submarine cable (300) laid in a static section installed on the seabed as shown in FIG. 1, a lead sheath can be used as the metal shielding layer (15). However, in the case of a dynamic submarine cable (100), there is a concern that the lead sheath may be subject to fatigue failure due to cable behavior. Therefore, a plurality of shielding wires made of a material such as copper may be wound horizontally, and a metal tape (153) wound horizontally across the shielding wires (151) may be applied as the metal shielding layer (15).

[0061] On the outside of the above metal shielding layer (15), a polymer sheath (16) composed of a resin such as polyvinyl chloride (PVC), polyethylene, etc. is extruded to improve the corrosion resistance and water resistance of the submarine cable, and to protect the cable from mechanical trauma and other external environmental factors such as heat and ultraviolet rays. In particular, in the case of submarine cables, it is preferable to use a polyethylene resin with excellent water resistance.

[0062] In addition, the power unit (10) may additionally be provided with a copper wire direct insertion tape (not shown) or a moisture absorption layer (not shown) between the metal shielding layer (15) and the external semiconducting layer (14). In addition, a moisture absorption layer (not shown) may additionally be provided between the metal shielding layer (15) and the polymer sheath (16).

[0063] The above copper wire direct tape is composed of copper wire and non-woven tape, etc., and can function to facilitate electrical contact between the external semiconducting layer and the metal shielding layer (15).

[0064] The above moisture-absorbing layer (not shown) may be formed in the form of a powder, tape, coating layer, or film containing a super absorbent polymer (SAP) that rapidly absorbs moisture that has penetrated the cable and has excellent ability to maintain an absorbed swelling state. Accordingly, the moisture-absorbing layer can prevent moisture from penetrating in the longitudinal direction of the cable. In addition, the moisture-absorbing layer may be configured to include a copper wire to prevent rapid electric field changes in the moisture-absorbing layer.

[0065] In particular, when applying a shielding wire and metal tape (153) as a metal shielding layer (15) laid in the dynamic section of Fig. 1, the water-proofing performance is lower than that of a soft skin system, so it is desirable to additionally provide a moisture-absorbing layer (not shown) to improve the water-proofing performance.

[0066] Meanwhile, the above submarine cable (100) may further include an optical unit (20).

[0067] Here, the optical unit (20) may be equipped with at least one optical fiber (21) and a tube (22) that accommodates the optical fiber (21).

[0068] The above optical unit (20) comprises a predetermined number of optical fibers (21) mounted together with fillers (not shown) within a tube (22), and the tube (22) may be made of a rigid material such as stainless steel. In addition, the optical unit (20) may further comprise a metal sheath (23) and a polymer sheath (24) surrounding the tube (22).

[0069] As illustrated in FIG. 2, the submarine cable (100) according to the present invention may include a plurality of shape fillers (30) to maintain the plurality of power units (10) spaced apart from each other and to form the submarine cable (100) into a circular shape overall.

[0070] In the past, fillers were made of yarns made of polypropylene, but the present invention can be provided with a shape filler (3) as a filler that is more advantageous in maintaining the cable shape of the submarine cable and protecting the internal components. The shape filler (30) is provided as a shape insert extruded from a material such as high-density polyethylene (HDPE) or polyethylene (PE) that has excellent chemical resistance, weather resistance (ability to withstand various climates), and water pressure resistance.

[0071] In addition, the shape filler (30) can accommodate a light unit (20) in a light unit receiving portion (35) formed therein. A detailed description of the shape filler (30) will be described later with reference to FIGS. 3 to 6.

[0072] In addition, as illustrated in Fig. 2, a binding tape layer (60) may be further provided to wrap a plurality of shape fillers (30) so that the cable core portion maintains a circular shape. The binding tape layer (60) may enable a plurality of shape fillers (30) to remain in a mutually supported state.

[0073] Meanwhile, the submarine cable (100) illustrated in FIG. 2 may be provided with a cable protection layer to protect internal components even in harsh environments such as seawater and salt in the ocean.

[0074] As illustrated in FIG. 2, according to an embodiment of the present invention, the cable protection layer of the submarine cable may include a bedding layer (70) provided on the outside of the shape filler (30).

[0075] The above bedding layer (70) can serve as a cushion for arranging an armor layer in which armor wires are arranged in at least one layer. The above bedding layer (70) can be provided with two armor layers (80a, 80b) on the outside to enhance the mechanical strength of the submarine cable (100) in a rough underwater environment, and a sheath made of a polymer resin material that serves as the outermost layer (110) of the armor layers (80a, 80b) on the outside to serve as a cable jacket.

[0076] For example, the above-mentioned sheath is made of a polymer resin such as polyvinyl chloride (PVC), polyethylene, etc. by extrusion, and can protect the armor layer (80a, 80b) while minimizing damage to the submarine cable (100) caused by waves and currents in a rough underwater environment, thereby ensuring sufficient durability.

[0077] The above armor layer (80a, 80b) can be configured by spirally winding a plurality of armor wires on the outside of the bedding layer (70), and not only performs the function of reinforcing the mechanical properties and performance of the submarine cable (100), but also additionally protects the submarine cable (100) from external force.

[0078] It is preferable that the armor wire constituting the above armor layer (80a, 80b) is composed of a metallic material, but it may also be composed of a non-metallic material as long as it has high tensile strength.

[0079] In the case of armor wire made of metal, it can be provided in the form of a wire wound horizontally, made of steel, galvanized steel, copper, brass, bronze, etc., and having a cross-sectional shape such as circular or flat, and in the case of non-metal armor wire, it can be provided in the form of a wire made of a material such as aramid fiber or ultra-high molecular weight polyethylene fiber, which is a high-tensile material.

[0080] In the following, the embodiments of the present invention are described as using a metal armor layer formed of metal armor wire, but the present invention is not limited thereto.

[0081] The armor wire constituting the metal armor layer may be spirally wound around the outer surface of the bedding layer (70), and preferably, may be wound in the Z direction or S direction, which is opposite to the assembly direction of the power unit (10).

[0082] And as shown in Fig. 2, in the case of a submarine cable installed in a dynamic section, if multiple armor layers (80) are provided to reinforce rigidity, the transverse winding directions may be different from each other.

[0083] Typically, a submarine cable (300 in Fig. 1) laid in a static section may have a single-layer armor layer and a serving layer as the outermost layer outside the armor layer. However, in the case of a submarine cable (100) laid in a dynamic section, a sheath made of a polymer resin material that serves as a cable jacket may be provided as the outermost layer (110) outside the armor layer.

[0084] The dynamic submarine cable (100) configured in this manner has a stronger cable protection layer than the static submarine cable (300 in Fig. 1) because continuous bending or bending occurs.

[0085] In the process of continuous bending or bending of the submarine cable during underwater installation, the cable protection layer exerts strong pressure on the inside, which can easily damage the metal shielding layer (15) of each power unit (10).

[0086] That is, when bending or bending of the submarine cable (100) occurs, the armor wire constituting the cable protection layer can strongly press the shielding wire (151) or metal tape (153) constituting the metal shielding layer (15) of the power unit (10) placed therein.

[0087] Typically, each power unit (10) constituting a submarine cable (100) is spaced apart from each other, and a plurality of shape fillers (3) are provided to fill the empty space between the power units (10). That is, the power units (10) and the shape fillers (30) are alternately exposed, and the cable protection layer is provided to surround the power units (10) and the shape fillers (30). In a submarine cable (100) having this structure, the power units (10) are provided in contact with the cable protection layer, and the ends of the plurality of shape fillers (30) are provided spaced apart from each other. Therefore, in a bending or bending situation of a submarine cable (100), the power unit (10) may not only be directly compressed by the cable protection layer, but also be strongly compressed by the spaced ends of the shape filler (30), so that the metal shielding layer (15) constituting the power unit (10) may be damaged.

[0088] Damage to the metal shielding layer (15) may mean damage such as a short circuit in the shielding wire (151), a kink in which the shielding wire (151) remains in a twisted state that cannot be recovered, or a tear in the metal tape (153) caused by the shielding wire (151).

[0089] Accordingly, the present invention has changed the shape of the shape filler (30) so as to prevent damage to the metal shielding layer (15) constituting the power unit (10) even when bending and bending of the dynamic submarine cable (100) occur. This will be described in detail with reference to FIG. 3 and below.

[0090] Figure 3 shows a cross-sectional view of one embodiment of a submarine cable (100) according to the present invention.

[0091] The submarine cable illustrated in FIG. 3 can be configured to include three power units (10) and three shape fillers (30).

[0092] Each shape filler (30) maintains a plurality of the power units (10) spaced apart from each other and ensures that the submarine cable (100) has a circular cross-section.

[0093] In addition, the shape filler (30) of the submarine cable (100) according to the present invention has a characteristic that, unlike conventional shape fillers, at least one of the circumferential ends has a surface that contacts the end of an adjacent shape filler (30).

[0094] As shown in FIGS. 2 and 3, each of the power unit (10) and the shape filler (30) is provided in three units.

[0095] Each of the above-described shape fillers (30) is provided with one outer circumferential surface (31) in the form of an outwardly convex circular arc and two inner circumferential surfaces (32) in the form of an inwardly concave circular arc on which the power units (10) are respectively arranged, and both ends (34) of each shape filler (30) are provided with side surfaces having a thickness for being supported by an adjacent shape filler (30), so that a surface may exist that is in contact with and supported by the end side surface of the adjacent shape filler (30). Both circumferential ends (34) of the shape filler (30) may be in surface contact with the circumferential end of the adjacent shape filler (30), but is not limited thereto. That is, only one end of the circumferential ends (34) of the shape filler (30) may be in surface contact with the circumferential end of the adjacent shape filler (30).

[0096] Additionally, the entire longitudinal end portions (34) of the shape filler (30) may be in surface contact with the longitudinal end portion of the adjacent shape filler (30), or only a portion of the longitudinal end portions (34) of the shape filler (30) may be in surface contact with the longitudinal end portion of the adjacent shape filler (30).

[0097] That is, if there is at least a part of the surface where both ends of the shape filler (30) are in contact with the ends of the adjacent shape filler (30) in the circumferential direction or in the longitudinal direction, it should be considered to correspond to this embodiment. Hereinafter, an example in which all ends of the adjacent shape fillers (30) are in surface contact will be described, but as described above, it is not limited thereto. In addition, the radius of the arc formed by the inner circumferential surfaces of the shape fillers in the surface contact submarine cable (100) according to the present invention may be provided to be larger than the diameter of the power unit.

[0098] As an example, a pair of adjacent shape fillers (30) may be in surface contact with each other so that their inner surfaces form an arc, and a space for arranging a power unit (10) may be formed inside one of the arcs. Since the radius of the arc formed by the inner surfaces of the shape fillers (30), i.e., the arrangement space, is larger than the outer diameter of the power unit (10), a gap (d) may exist between the power unit (10) and the shape filler. The gap (d) may be 1 mm or more, but is not limited thereto.

[0099] The gap (d) between the shape filler (30) and the power unit (10) of the submarine cable (100) may vary during the joining process of the power unit (10) and the shape filler (30), the manufacturing process after joining, the underwater laying process, and the use process after the underwater laying. For example, a part of the inner surface of the shape filler (30) may be in contact with the power unit (10) so that the gap is 0, and the gap may gradually increase on another part of the inner surface of the shape filler (30). That is, the power unit (10) of the submarine cable may move in position within the gap space with the shape filler (30) depending on an environment such as bending, and in this case, the gap (d) may vary.

[0100] Therefore, according to the submarine cable (100) according to the present invention, since the plurality of power units (10) are kept in a mutually spaced state and the ends of adjacent shape fillers (30) among the plurality of shape fillers (30) that form the cross-sectional shape of the submarine cable (100) into a circle are in surface contact, the power unit (10) is prevented from being directly pressed by the cable protection layer in a bending or bending situation of the submarine cable (100), and strong pressure by the spaced ends of the shape fillers (30) can be prevented, thereby minimizing damage to the metal shielding layer (15) of the power unit (10).

[0101] In addition, according to the submarine cable (100) according to the present invention, since the power unit (10) is provided at a predetermined distance (d) from the inner surface of a plurality of shape fillers (30) with which it makes surface contact, the frictional force between the shape fillers (30) and the power unit (10) is reduced, thereby minimizing damage to the metal shielding layer (15) that may occur in a bending or bending situation of the submarine cable (100).

[0102] Meanwhile, the inner end (35) of each shape filler (30) may extend toward the center of the submarine cable. Accordingly, power units (10) spaced apart from each other by a preset interval (d) in an arc formed by the inner surfaces of adjacent shape fillers (30) can be accommodated over half of the outer surface, so that a plurality of power units (10) can be maintained spaced apart from each other.

[0103] In addition, an inlet for introducing a light unit into the light unit receiving portion (33) may be formed at the inner end (35) of each shape filler (30). The inlet may be provided by cutting the inner end (35) of the shape filler (30) to the light unit receiving portion (33).

[0104] Figure 4 shows a cross-sectional view of another embodiment of a submarine cable (100) according to the present invention.

[0105] In the embodiment illustrated in FIG. 3, three power units (10) have an empty space (S) in the center, so that when the power units (10) and the shape fillers (30) are connected or when bending or bending of the submarine cable (100) occurs significantly, the power units (10) may move into the empty space (S), and the distance (d) between the shape fillers (30) and the power units (10) may increase due to the movement of the power units (10). In this case, a misalignment may occur between the two ends of the plurality of shape fillers (30) that are in surface contact, so that the support structure between the shape fillers (30) may not be maintained, resulting in damage to the metal shielding layer (15) of the power unit (10).

[0106] To prevent this, as in the embodiment illustrated in FIG. 4, the submarine cable (100) according to the present invention may additionally be provided with a center filler (50a) in the central empty space (S).

[0107] The center filler (50a), like the shape filler (30), may be formed of a shaped member extruded from a material such as high-density polyethylene (HDPE) or polyethylene (PE) that has excellent chemical resistance, weather resistance (ability to withstand various climates), and water pressure resistance. The center filler (50a) may have three concave outer surfaces that support three power units (10) at the center of the submarine cable (100). As illustrated in Fig. 4, the center filler (50a) may not have a hollow portion, but is not limited thereto, and may be formed with one or more hollow portions.

[0108] Accordingly, when the power unit (10) and the shape filler (30) are connected by the center filler (50a) or when bending or bending of the submarine cable (100) occurs significantly, each power unit (10) is prevented from moving toward the center, so that the support structure by the surface contact between the two ends of the plurality of shape fillers (30) can be stably maintained, thereby further minimizing damage to the metal shielding layer (15) of the power unit (10).

[0109] Figure 5 shows a cross-sectional view of another embodiment of a submarine cable (100) according to the present invention.

[0110] In the embodiment shown in FIG. 4, the center filler (50a) has three concave outer surfaces for supporting the outer surface of each power unit (10), and three outer ends (51) provided between the concave outer surfaces are spaced apart from the inner ends (35) of each shape filler (30) so that an empty space may exist therebetween.

[0111] However, the embodiment illustrated in FIG. 5 may be provided such that the plurality of outer ends of the center filler (50b) are supported by making surface contact with the inner ends (35) of each shape filler (30).

[0112] In this case, the inner end (35) of each shape filler (30) or the outer end of each center filler (50b) may be extended so that no empty space exists between the shape filler (30) and the center filler (51b). However, it is preferable that the inner end (35) of each shape filler (30) be provided in an extended manner. While the center filler (50b) is provided in contact with the power unit (10), each shape filler (30) is provided spaced apart from the power unit (10) by a preset distance (d). Therefore, when the inner end (35) of each shape filler (30) is provided in an extended manner, the frictional force between the power unit (10) and the shape filler (30) and the center filler (50b) can be further reduced.

[0113] When the multiple outer ends of the center filler (50b) are provided to be supported by making surface contact with the inner ends (35) of each shape filler (30), the structure between the center filler (50b) and the shape filler (30) is supported more stably, so that damage to the metal shielding layer (15) of the power unit (10) that may occur when the submarine cable (100) is bent or flexed can be further minimized.

[0114] Figure 6 shows a cross-sectional view of another embodiment of a submarine cable (100) according to the present invention.

[0115] In the embodiments illustrated in FIGS. 3 to 5, in order to prevent damage to the metal shielding layer (15) of the power unit (10) of the submarine cable, the circumferential ends of each shape filler (30) are supported by making surface contact with the ends of adjacent shape fillers (30), and each shape filler (30) is provided spaced apart from each of the plurality of power units (10) by a preset interval (d).

[0116] However, even if both ends of adjacent shape fillers (30) are supported by making surface contact, when the submarine cable is bent or bent, both ends of adjacent shape fillers (30) may spread out in the circumferential direction, or a warp may occur between both ends of adjacent shape fillers (30), so that the support structure between the shape fillers (30) may not be maintained.

[0117] Accordingly, in the embodiment illustrated in FIG. 5, each of the shape fillers (30) is supported by having both circumferential ends (34) in surface contact, and the shape filler (30) may additionally be provided with a fixing means that is mutually fixed to the ends of the shape filler (30) adjacent to the both circumferential ends.

[0118] Specifically, the fixing means is configured with a hook (36) provided at one end of each of the two ends of the shape filler (30) and a hook groove (37) in which the hook (36) is received at the other end, so that the hook (36) provided at one end of one of the two adjacent shape fillers (30) can be hooked and fixed to the hook groove (37) of the other shape filler (30).

[0119] The above-mentioned hook (36) may be configured to have a shape that extends from the side of one end of the shape filler (30) and expands in width toward the outside. In this case, the hook groove (37) may be configured as a groove having a shape corresponding to the hook groove (36) so that the hook groove (36) can be hooked and fixed.

[0120] For example, the above-mentioned hook (36) may be configured such that the cross-section extends from one side and the end is circular as shown in FIG. 6, and the hook groove (37) may be configured as a groove having a shape corresponding to the hook groove (36) in which the circular hook (36) is hooked and fixed. However, the shapes of the hook (36) and the hook groove (37) may be variously changed as long as a hooking and fixing function can be provided.

[0121] Meanwhile, the catches (36) and catch grooves (37) provided in the shape filler (30) may be provided to extend along the length of the power unit (10). In this case, when a plurality of power units (10) and a plurality of shape fillers (30) are connected, the catches (36) and catch grooves (37) are continuously caught and fixed, thereby forming a stably supported structure.

[0122] As described above, the shape filler (30) is supported by having both circumferential ends (34) in surface contact, but if the shape filler (30) is additionally provided with a fixing means that is mutually hooked and fixed to the ends of the shape filler (30) adjacent to both circumferential ends, when the submarine cable is bent or curved, the ends of the adjacent shape fillers (30) are prevented from spreading out in the circumferential direction or from twisting between the ends, so that the support structure between the shape fillers (30) can be stably maintained.

[0123] Meanwhile, FIG. 6 illustrates that a center pillar (50b) is provided at the center of the submarine cable (100), and the inner end (35) of each shape pillar (30) and the outer end of the center pillar (50b) are supported by making surface contact, but this is not limited thereto. That is, the center pillar (50b) may not be provided at the center of the submarine cable (100), and only a fixing means may be provided that is mutually hooked and fixed to the ends of the shape pillar (30) adjacent to the circumferential ends of the shape pillar (30). Even if the center pillar (50b) is not provided, if a fixing means is provided on the shape pillar (30), the structure in which the shape pillar (30) is made surface contact and is hooked and fixed can be stably maintained, and thus, the occurrence of twisting between the ends of the shape pillar (30) can be prevented.

[0124] While this specification has described preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims below. Therefore, any modified implementation that fundamentally includes the elements of the claims should be considered within the technical scope of the present invention.

Claims

1. As a submarine cable for underwater installation, A plurality of power units including a conductor, an insulating layer surrounding the conductor, and a metal shielding layer surrounding the insulating layer; A plurality of shape fillers for maintaining the plurality of said power units in a mutually spaced state and for making the submarine cable have a circular cross-section; and A cable protection layer provided on the outer side of a plurality of the above shape fillers; A submarine cable, characterized in that at least one end of each of the above-mentioned shape fillers has a surface that contacts the circumferential end of an adjacent shape filler.

2. In paragraph 1, A submarine cable characterized in that the radius of the arc formed by the inner surface of the shape fillers that are in contact with each other is larger than the diameter of the power unit.

3. In paragraph 2, A submarine cable, characterized in that each of the above-mentioned shape fillers is additionally provided with a fixing means that is mutually engaged with the end of the shape filler adjacent to both ends in the circumferential direction.

4. In paragraph 3, A submarine cable characterized in that the above fixing means comprises a catch provided at one end of each of the two ends of the shape fillers and a catch groove for receiving the catch at the other end, such that the catch provided at one end of one of the two adjacent shape fillers is caught and fixed in the catch groove provided at the other end of the other shape filler.

5. In paragraph 4 A submarine cable characterized in that the catch and catch groove provided on the above shape filler are provided so as to extend along the length direction of the power unit.

6. In paragraph 4 A submarine cable characterized in that the above-mentioned stumbling block is configured in a shape in which the width extends from a side of one end of the shape filler and expands outward.

7. In paragraph 1 A submarine cable characterized in that an optical unit receiving portion is provided inside the shape filler for receiving an optical unit having at least one optical fiber.

8. In Article 7 A submarine cable characterized in that the inner end of the above shape filler is formed with an incision through which an optical unit can be inserted.

9. In paragraph 1 A submarine cable characterized in that each of the power units and the shape fillers is provided in three units, each of the shape fillers is provided with two inner peripheral surfaces in a curved shape, a pair of adjacent shape fillers are in surface contact with each other so that the inner peripheral surfaces form one circular arc, and a placement space in which one power unit is arranged is formed inside one circular arc.

10. In paragraph 1 A submarine cable characterized in that a center pillar having a plurality of concave outer surfaces for supporting a plurality of power units is additionally provided at the center of the submarine cable.

11. In Article 10 A submarine cable characterized in that each of the inner ends of the above-mentioned shape fillers and the plurality of outer ends of the above-mentioned center fillers are in surface contact.

12. In paragraph 1 A submarine cable further characterized by comprising a binding tape layer wrapping a plurality of the above-described shape fillers.

13. In Article 12 A submarine cable, characterized in that the cable protection layer comprises a bedding layer provided on the outside of the binding tape layer, at least one armor wire layer provided on the outside of the bedding layer, and an outermost layer provided on the outside of the armor wire layer.

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