Field repair joint for submarine cable and method of restraining submarine cable thereof

Abstract

The present invention relates to a field recovery junction box, and more specifically, to a field recovery junction box capable of easily and quickly recovering a submarine cable at sea, preventing the detachment of the submarine cable, and stably securing the submarine cable. A field repair connection box according to one embodiment of the present invention comprises: an outer case in the shape of a tube with a hollow interior; and flanges configured to be coupled to each end of the outer case; wherein the flanges comprise: a first part in the shape of a plate disposed inside the outer case and having a first through hole formed therein; a second part comprising a base portion in the shape of a tube having a second through hole and a first ring portion disposed at one end of the base portion and disposed to face the first part; and a third part in the shape of a horn having a volume that can be disposed inside the second through hole and having a third through hole, and which is housed inside the second through hole by the first part.

Description

Technology Field

[0001] The present invention relates to a field repair junction box for a submarine cable and a method for securing a submarine cable using the same. More specifically, the invention relates to a field repair junction box for a submarine cable and a method for securing a submarine cable using the same, which allows for easy and rapid repair of a submarine cable at sea, prevents the submarine cable from falling off due to load, and stably secures the submarine cable. Background Technology

[0002] A submarine cable is a cable installed on the seabed to transmit electricity between two points separated by the sea.

[0003] For submarine cables, it is very important to ensure robust connections between cables and watertightness of the connections during initial installation, and to perform rapid and economical maintenance in the event of damage to the cables caused by seawater currents due to climate change, special fishing gear, or anchors of anchored fishing vessels due to fishing activities.

[0004] When installing a submarine cable, that is, when connecting communication means over a short distance, a single cable can be laid directly on the seabed and connected to each communication means at both ends. However, when connecting areas separated by a long distance of more than tens of kilometers, installation with only a single cable is impossible, so two or more cables are connected using a connecting device and laid on the seabed. In addition, if damage occurs to a submarine cable laid on the seabed as described above due to severe climate change or fishing activities, the damaged part of the cable is repaired by towing it onto a ship, cutting the damaged section of the cable, placing a spare cable in the middle, and connecting it on both sides using a connecting device.

[0005] The core technology for submarine cable connection devices is to maintain a robust connection without deformation due to tension after connecting to the submarine cable, while simultaneously ensuring internal watertightness even during long-term use. Furthermore, convenience for assembly, construction, and relocation during connection work must be guaranteed.

[0006] The average lifespan of a submarine cable is approximately 20 to 25 years, but submarine cables can be damaged due to unexpected conditions on the seabed. Damaged submarine cables can be repaired on board a ship at sea using a Field Repair Joint.

[0007] When a damaged submarine cable is repaired at the on-site repair junction box on the aforementioned vessel and then installed in the sea, a load is generated at both ends of the on-site repair junction box due to the self-load of the submarine cable. To prevent the submarine cable from detaching due to this load, conventionally, the submarine cable was secured to the on-site repair junction box using a specific device with a restraining force. Prior art literature

[0008] Republic of Korea Published Patent No. 10-2014-0115509 (October 1, 2014) The problem to be solved

[0009] The problem that the present invention aims to solve is to provide a field recovery junction box for a submarine cable and a method for securing the submarine cable thereof, which can prevent the submarine cable from falling off due to its own weight.

[0010] In addition, the invention provides a field recovery junction box for a submarine cable capable of stably securing an installed submarine cable, and a method for securing a submarine cable using the same.

[0011] In addition, the invention provides a field recovery junction box for submarine cables capable of preventing the penetration of moisture, such as seawater, from the outside to the inside, and a method for securing the submarine cables thereof. means of solving the problem

[0012] A field repair connection box according to one embodiment of the present invention comprises: an outer case in the shape of a tube with a hollow interior; and flanges configured to be coupled to each end of the outer case; wherein the flanges comprise: a first part in the shape of a plate disposed inside the outer case and having a first through hole formed therein; a second part comprising a base portion in the shape of a tube having a second through hole and a first ring portion disposed at one end of the base portion and disposed to face the first part; and a third part in the shape of a horn having a volume that can be disposed inside the second through hole and having a third through hole, and which is housed inside the second through hole by the first part.

[0013] A field repair connection box according to another embodiment of the present invention comprises: a cylindrical outer case; and a flange configured to be coupled to openings at both ends of the outer case; wherein the flange comprises a disc, a cylindrical portion, and a truncated cone for fixing a plurality of steel wires of the submarine cable, and each of the disc, the cylindrical portion, and the truncated cone has a through hole into which the submarine cable can be inserted, and the truncated cone is positioned inside the through hole of the cylindrical portion through an opening on one side of the cylindrical portion, and the disc is positioned to block the opening on one side of the cylindrical portion, and a portion of the plurality of steel wires of the submarine cable is configured to be inserted between the inner surface of the cylindrical portion defining the through hole of the cylindrical portion and the outer surface of the truncated cone, and another portion of the plurality of steel wires of the submarine cable is configured to be inserted between one end of the cylindrical portion and the disc.

[0014] A method according to another embodiment of the present invention is a method for securing a submarine cable comprising a plurality of steel wires and an outer sheath layer surrounding the plurality of steel wires to a field recovery junction box of claim 1, comprising the steps of: removing the outer sheath layer at the end of the submarine cable to expose the plurality of steel wires to the outside; passing the submarine cable through a second through-hole of the second part and then bending the plurality of steel wires outward; passing the submarine cable through a third through-hole of the third part and then inserting the third part into the second through-hole so that the plurality of steel wires are sandwiched between the second part and the third part; passing the submarine cable through a first through-hole of the first part and then pressing the first part toward the first ring portion of the second part; and joining the first part and the first ring portion through a fastening means so that the first part is in maximum contact with the first ring portion and the plurality of steel wires are sandwiched between the first part and the first ring portion. The method includes the step of cutting off the externally exposed ends of the plurality of steel wires sandwiched between the first part and the first ring part; and the step of injecting a liquid compound into an injection hole connected to a second through hole of the base part and curing it. Effects of the invention

[0015] By using the field recovery junction box for a submarine cable and the submarine cable restraint method according to the present invention, the detachment of the submarine cable due to the self-weight of the submarine cable can be prevented.

[0016] In addition, it can stably secure installed submarine cables.

[0017] In addition, it can prevent the penetration of moisture, such as seawater, from the outside to the inside. Brief explanation of the drawing

[0018] FIG. 1 (a) and (b) are drawings illustrating examples of submarine cables that can be installed in a field recovery junction box according to one embodiment of the present invention. FIG. 2 is a perspective view of an on-site repair junction box according to one embodiment of the present invention, which can repair or restore the submarine cable illustrated in FIG. 1 on board a ship at sea. FIG. 3 is an enlarged perspective view of a part of a field recovery connection box according to one embodiment of the present invention shown in FIG. 2. FIG. 4 is an exploded perspective view of only the first flange (300a) shown in FIG. 3. FIG. 5 is a cross-sectional perspective view of the second part (330) and the third part (350) shown in FIG. 4 combined. Figure 6 is an enlarged view of A in Figure 5. FIG. 7 is a perspective view of the end portion of the submarine cable shown in FIG. 1 (b) to be coupled to the first flange (300a) shown in FIG. 2 to 6. FIGS. 8 to 13 are drawings for explaining a method of securing the submarine cable shown in FIG. 7 to the first flange (300a) shown in FIGS. 2 to 6. FIG. 14 is a conceptual diagram showing the state in which a submarine cable is restored inside a field recovery junction box according to one embodiment of the present invention illustrated in FIG. 2. Specific details for implementing the invention

[0019] The following detailed description of the invention refers to the accompanying drawings, which illustrate specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that various embodiments of the invention are different but need not be mutually exclusive.

[0020] There are alternating current (AC) submarine cables and direct current (DC) submarine cables.

[0021] AC submarine cables are primarily used for medium to long distances (100 km or less) due to the advantage of not incurring additional costs when connected to existing underground systems, and 3-core or single-core submarine cables can be applied. Typically, XLPE insulation is applied, and XLPE insulated cables are widely used for submarine cables due to their advantages such as easy installation and maintenance, simple connection and repair, and excellent chemical and electrical properties.

[0022] Because DC submarine cables have a lower peak voltage compared to AC, they allow for thinner insulation, enabling cost reduction; furthermore, unlike AC, they do not have frequency-related losses (such as external loss and dielectric loss). Additionally, since they can be interconnected with other power systems having different frequencies and voltages, they offer the advantage of being free from electrical and technical constraints during international interconnections.

[0023] Below, with reference to Fig. 1, we will examine the structure of a submarine cable.

[0024] FIGS. 1 (a) and (b) are drawings illustrating examples of submarine cables that can be installed in a Field Repair Joint (FRJ) according to one embodiment of the present invention.

[0025] The submarine cable shown in Fig. 1(a) is an example of a DC submarine cable.

[0026] Referring to FIG. 1 (a), the DC submarine cable includes a conductor (10), an inner semiconducting layer (12), an insulating layer (14), an outer semiconducting layer (16), a steel wire layer (18), and an outer sheath layer (20).

[0027] A conductor (10) is positioned in the center and serves as a passage for current flow. For example, the conductor (10) is made of copper or aluminum. The conductor (10) may also be composed of multiple strands.

[0028] The inner semiconducting layer (12) surrounds the conductor (10) and evenly distributes the charge on the surface of the conductor to make the electric field uniform, thereby improving the dielectric strength of the insulating layer (14) described later. Furthermore, it prevents the formation of a gap between the conductor (10) and the insulating layer (14), thereby preventing corona discharge and ionization. In addition, the inner semiconducting layer (12) also serves to prevent the insulating layer (14) from penetrating into the conductor (10) during the production of the DC submarine cable.

[0029] The insulating layer (14) surrounds the inner semiconducting layer (12) and electrically insulates the conductor (10) from the outside. The insulating layer (14) may be made of a material such as, for example, XLPE (Cross-linked Polyethylene).

[0030] The outer semiconducting layer (16) surrounds the insulating layer (14) and creates an equipotential distribution of electric field lines between it and the inner semiconducting layer (12), thereby improving the dielectric strength of the insulating layer (14).

[0031] On the outside of the outer semiconducting layer (16), a shielding layer (not shown) or a steel wire layer (18) made of a metal sheath is provided depending on the type of cable. The shielding layer or steel wire layer (18) is provided for electrical shielding and for the return path of short-circuit current.

[0032] An outer sheath layer (20) is provided on the outermost part of the DC submarine cable. The outer sheath layer (20) serves to protect the components located on the inside. The outer sheath (20) is made of a material with excellent weather resistance to withstand various natural environments, including light, wind and rain, moisture, and gases in the air, chemical resistance to withstand chemicals, and mechanical strength. For example, it may be made of PVC (Polyvinyl chloride) or PE (Polyethylene).

[0033] The submarine cable shown in Fig. 1(b) is an example of an alternating current submarine cable.

[0034] Referring to Fig. 1(b), the AC submarine cable includes three internal cables and an optical cable (30).

[0035] Each of the above inner cables comprises a conductor (10), an inner semiconducting layer (12), an insulating layer (14), an outer semiconducting layer (15), a metal sheath layer (17), and a protective layer (19). Additionally, it comprises a bedding layer (21) surrounding the three inner cables and the optical cable (30), a plurality of steel wires (18) surrounding the bedding layer (21), and an outer sheath layer (20) surrounding the plurality of steel wires (18).

[0036] A field repair junction box according to one embodiment of the present invention is a junction box for connecting a faulty submarine cable at sea when a fault occurs in a submarine cable illustrated in FIG. 1 (a) or (b) installed in the sea. Such a field repair junction box can prevent shear of force in the connection material by fixing axial stress generated by loads, etc., during installation. Compared to conventional ground junction boxes installed on land, it is intended for connecting submarine cables at sea where the installation environment and external conditions are poor.

[0037] Hereinafter, with reference to FIGS. 2 to 14, we will examine a field recovery connection box according to one embodiment of the present invention.

[0038] FIG. 2 is a perspective view of an on-site repair junction box according to one embodiment of the present invention, which can repair or restore the submarine cable illustrated in FIG. 1 on board a ship at sea.

[0039] Referring to FIG. 2, a field repair connection box according to one embodiment of the present invention includes an outer case (100) and a flange (300).

[0040] The outer case (100) has a hollow, tubular shape. For example, the outer case (100) may be cylindrical, polygonal, elliptical, etc. In the drawing, it is typically depicted as cylindrical. Both ends of the outer case (100) are open, and flanges (300) are attached to each end.

[0041] The outer case (100) is a device that withstands mechanical stress caused by external force and may not have a waterproof function itself.

[0042] The outer case (100) includes a plurality of outer cases (100a, 100b, 100c, 100d). For example, the outer case (100) may be composed of four first to fourth outer cases (100a, 100b, 100c, 100d). The first to fourth outer cases (100a, 100b, 100c, 100d) may be combined to form a cylindrical outer case (100).

[0043] A third outer case (100c) may be disposed on one side of the first outer case (100a), a fourth outer case (100d) may be disposed on one side of the second outer case (100b), the second outer case (100b) may be disposed below the first outer case (100a), and the fourth outer case (100b) may be disposed below the third outer case (100c). These may be firmly fastened together using fastening means such as bolts and nuts.

[0044] When the outer case (100) is composed of first to fourth outer cases (100a, 100b, 100c, 100d), it is easy to surround the repaired submarine cable with the first to fourth outer cases (100a, 100b, 100c, 100d) after electrically and physically connecting the damaged or severed submarine cable. Thus, the repair of the submarine cable can be completed quickly and easily.

[0045] The material of the outer case (100) can be composed of a material that can mitigate or prevent rust formation and withstand high external water pressure on the seabed.

[0046] A flange (300) is attached to each of the two ends of a cylindrical outer case (100). The flange (300) includes a first flange (300a) attached to one end of the outer case (100) and a second flange (300b) attached to the other end of the outer case (100).

[0047] A submarine cable is securely and stably connected to each of the first and second flanges (300a, 300b). The end of the first submarine cable is connected to the first flange (300a), and the end of the second submarine cable is connected to the flange (300b). Here, the first submarine cable and the second submarine cable may be different submarine cables. Alternatively, the first submarine cable and the second submarine cable may have originally been a single submarine cable, but a part of it was separated by an external force and divided into two.

[0048] Referring to FIGS. 3 to 6, the detailed configuration of each flange (300) is examined. Here, since the first flange (300a) and the second flange (300b) are identical to each other, only the first flange (300a) is described below, and the second flange (300b) is replaced by the description of the first flange (300a).

[0049] FIG. 3 is an enlarged perspective view of a part of a field repair connection box according to an embodiment of the present invention shown in FIG. 2, FIG. 4 is an exploded perspective view of only the first flange (300a) shown in FIG. 3, FIG. 5 is a cross-sectional perspective view of the second part (330) and the third part (350) shown in FIG. 4 combined, and FIG. 6 is an enlarged view of A in FIG. 5.

[0050] Referring to FIGS. 2 through 6, the first flange (300a) includes a first part (310), a second part (330), and a third part (350).

[0051] The first part (310) has a plate shape with a first through hole (310h) formed in the center. Here, the plate may be a circular plate. A submarine cable illustrated in FIG. 1 may be placed in the first through hole (310h). The cross-sectional shape of the first through hole (310h) may be circular, corresponding to the outer shape of the submarine cable.

[0052] The first part (310) is placed inside the outer case (100). The first part (310) may have a shape and size corresponding to the inner diameter of the outer case.

[0053] A plurality of fastening holes (310B) are formed at the edge of the first part (310). Fastening means, such as a bolt inserted into the fastening hole (333B) of the first ring portion (333) of the second part (330), may be disposed in the fastening holes (310B).

[0054] The second part (330) includes a base part (331), a first ring part (333), a second ring part (335), and a third ring part (337).

[0055] The base portion (331) has a second through hole (330h) into which the submarine cable shown in FIG. 1 can be placed. The cross-sectional shape of the second through hole (330h) may be circular, corresponding to the outer shape of the submarine cable.

[0056] The base part (331) may have a cylindrical shape.

[0057] The base portion (331) has one or more injection holes (331j1, 331j2) connected to the second through hole (330h). The injection holes (331j1, 331j2) are holes used for injecting a liquid waterproofing compound. The liquid compound serves to fill the space or gap between the first flange (300a) and the submarine cable after the submarine cable shown in FIG. 1 is joined to the first flange (300a). The liquid compound hardens over time to prevent moisture from penetrating into the space or gap between the first flange (300a) and the submarine cable.

[0058] The first ring portion (333) is positioned at one end of the base portion (331) and is positioned to face the first part (310). The first ring portion (333) has a width or diameter greater than that of the base portion (331). The first ring portion (333) is positioned inside the outer case (100) together with the first part (310). The first ring portion (333) has a shape corresponding to the outer surface shape of the base portion (331). If the base portion (331) is cylindrical, the first ring portion (333) is a circular ring shape.

[0059] A plurality of fastening holes (333B) are formed at the edge of the first ring portion (333). Fastening means, such as a bolt inserted into the fastening hole (310B) of the first part (310), can be inserted through the fastening holes (333B).

[0060] The second ring portion (335) is positioned in the middle between one end and the other end of the base portion (331) and has a larger width or diameter than the first ring portion (333) and the third ring portion (335).

[0061] The second ring portion (335) is directly connected to the outer case (100). The second ring portion (335) and the outer case (100) can be connected to each other through fastening means such as bolts and nuts. A plurality of fastening holes (335B) are formed at the edge of the second ring portion (335). Fastening means, such as bolts inserted into the fastening holes of the outer case (100), can be inserted through the fastening holes (335B).

[0062] The third ring portion (337) is positioned at the other end of the base portion (331). The third ring portion (337) has a greater width or diameter than the base portion (331).

[0063] The third ring portion (337) may be connected to a bending adjuster (not shown) that controls the degree of bending of the submarine cable, although this is not shown in the drawing. The bending adjuster (not shown) may be connected to a bend stiffener or a bend restrictor. The third ring portion (337) and the bending adjuster (not shown) may be connected to each other through fastening means such as bolts and nuts. A plurality of fastening holes (337B) are formed at the edge of the third ring portion (337). Fastening means, such as bolts inserted into the fastening holes of the bending adjuster (not shown), may be inserted through the fastening holes (337B).

[0064] The third part (350) is placed inside the second through hole (330h) of the second part (330). The third part (350) may be placed inside one end of the base portion (331) of the second part (330).

[0065] The third part (350) has a frustum shape. Here, the frustum may be a truncated cone.

[0066] The third part (350) has a third through hole (350h) in which a submarine cable illustrated in FIG. 1 can be placed. The diameter of the third through hole (350h) is constant, but smaller than the diameter of the second through hole (330h) of the base part (331).

[0067] The thickness of one end of the base portion (331) surrounding the third part (350) increases from the first ring portion (333) toward the second ring portion (335). This shape prevents the third part (350) from slipping out through the second through hole (330h) of the second part (330) when the third part (350), which has a horn-shaped form, is inserted into the second through hole (330h) of the second part (330).

[0068] The third part (350) has a shape corresponding to the internal space of one end of the base part (331), but its volume is smaller than the volume of the internal space. Accordingly, a predetermined gap (G) is formed between the inner surface of the base part (331) of the second part (330) and the outer surface of the third part (350). A plurality of steel wires (18) of the submarine cable shown in FIG. 1 are placed in the gap (G).

[0069] FIG. 7 is a perspective view of the end portion of the submarine cable shown in FIG. 1 (b) to be coupled to the first flange (300a) shown in FIG. 2 to 6.

[0070] Referring to FIG. 7, when the outer sheath layer (20) of the end portion of the submarine cable shown in FIG. 1 (b) is removed, a plurality of steel wires (18) are exposed, and when the ends of the plurality of steel wires (18) are removed, a bedding layer (21) is exposed to the outside, and when the ends of the bedding layer (21) are removed, the protective layer (19) of the inner cable is exposed.

[0071] FIGS. 8 to 13 are drawings for explaining a method of securing the submarine cable shown in FIG. 7 to the first flange (300a) shown in FIGS. 2 to 6.

[0072] Referring to FIG. 8, the end portion of the submarine cable is passed through the through hole (330h, see FIG. 4) of the second part (330) so that the second part (330) is positioned on the outer sheath layer (20) of the submarine cable. Then, each of the externally exposed steel wires (18) is bent outward. The bent steel wires (18) are arranged in a radial pattern.

[0073] Next, referring to FIG. 9, the third part (350) is inserted into the end portion of the submarine cable, and likewise the first part (310) is inserted into the end portion of the submarine cable. The third part (350) and the first part (310) are positioned on the bedding layer (21) of the submarine cable.

[0074] Next, referring to FIG. 10, the third part (350) and the first part (310) are pushed toward the second part (330) so that the third part (350) enters the base portion (331) of the second part (330) and the first part (310) comes close to the first ring portion (333) of the second part (330).

[0075] When the first part (310) is brought somewhat close to the first ring portion (333) of the second part (330), a bolt (510B) is sequentially inserted into the fastening hole (310B) of the first part (310) and the fastening hole (333B) of the second part (330), and a nut (not shown) is fastened to the end of the bolt (510B). Bolts (510B) are also inserted into other fastening holes and nuts (not shown) are fastened.

[0076] Next, referring to FIG. 11, each bolt (510B) and nut (510N) is tightened as much as possible so that the first part (310) is as close as possible to the first ring portion (333) of the second part (330). Steel wires (18) are tightly fitted between the first part (310) and the second part (330).

[0077] Next, referring to FIG. 12, the portion exposed to the outside in each steel wire (18) is cut off as much as possible. Meanwhile, to block the gap between the first part (310) and the bedding layer (21) of the submarine cable, a shielding plate (700) may be further placed.

[0078] Next, referring to FIG. 13, a liquid compound (900) is injected into injection holes (331j1, 331j2) formed in the base portion (331) of the second part (330). The liquid compound (900) has adhesive properties upon curing and is intended to strengthen bonding (mechanical performance) with other components in contact. The liquid compound (900) can be injected into the injection holes (331j1, 331j2) using a funnel (950). The injected liquid compound (900) can fill the gaps and spaces between the steel wires (18) of the submarine cable inside the second through hole (330h) of the second part (330), the gap (G) between the second part (330) and the third part (350) into which the steel wires (18) are inserted, and the gaps and spaces between the first part (310) and the second part (330) into which the steel wires (18) are inserted. Afterward, when the liquid compound (900) hardens, it shrinks and the bonding strength with the steel wires (18) of the submarine cable is improved.

[0079] Meanwhile, to block the gap between the second part (330) and the outer layer (20) of the submarine cable, an additional shielding plate (750) may be placed.

[0080] FIG. 14 is a conceptual diagram showing the state in which a submarine cable is restored inside a field recovery junction box according to one embodiment of the present invention illustrated in FIG. 2.

[0081] Referring to FIG. 14, one side internal cable (1a) and the other side internal cable (1b) are electrically and physically connected inside the inner case (1900), and one side optical cable (30a) and the other side optical cable (30b) are electrically and physically connected inside the optical connection housing (3000).

[0082] Three internal cables (1a) and one optical cable (30a) placed on one side are included in one submarine cable (or first submarine cable), and three internal cables (1b) and one optical cable (30b) placed on the other side are included in another submarine cable (or second submarine cable).

[0083] Inside the inner case (1900), the conductor of the inner cable (1a) on one side and the conductor of the inner cable (1b) on the other side are electrically and physically connected to each other.

[0084] The inner case (1900) may be a structure that is separated into at least two or more parts and may be made of copper. The inner case (1900) may maintain waterproofing through lead smoke.

[0085] The inner case (1900) can be taped to the outside with multiple tapes.

[0086] The optical connection housing (3000) may include an inner housing made of resin material and an outer housing made of metal material. The optical connection housing (3000) uses a double housing to reliably electrically and physically connect optical cables to each other and prevent moisture penetration from the outside. Inside the inner housing, an optical cable (30a) on one side and an optical cable (30b) on the other side can be electrically connected to each other.

[0087] The optical connection housing (300) can be taped with multiple tapes on the outside.

[0088] A waterproofing compound (CP) may be filled inside the outer case (100d, 100b). The compound (CP) may be a polyurethane compound rather than an epoxy compound. Epoxy materials have the disadvantages of being weaker against pressure than polyurethane materials, relatively prone to cracking, and requiring a long installation time. Since the field repair junction box according to the embodiment of the present invention is subjected to high pressure underwater, there is a high possibility of water penetrating into the interior when cracks occur, and installation must be as fast as possible at sea, it is preferable that the compound (CP) be a polyurethane material. The polyurethane compound (CP) may be manufactured through performance tests of various material properties (pressure, strength, and contact force) according to special environments such as underwater.

[0089] By using the field recovery connection box according to one embodiment of the present invention illustrated in FIGS. 2 to 14 described above, if damage or an accident occurs to a submarine cable, the damaged submarine cable can be quickly and easily restored or repaired on board a ship at sea (a laying vessel or a recovery vessel).

[0090] In addition, the submarine cable connected to the field recovery junction box according to the embodiment of the present invention can withstand axial stress caused by the self-weight of the submarine cable even when installed in the sea. In particular, it can withstand various external forces generated when the field recovery junction box is lowered into the sea by a crane after being installed on board.

[0091] In addition, the field repair junction box according to an embodiment of the present invention can prevent water penetration into the interior due to external water pressure caused by sea depth. In particular, to prevent water penetration due to the external water pressure, water penetration can be prevented by injecting a compound with excellent interfacial contact force into the field repair junction box.

[0092] In addition, the field repair junction box according to an embodiment of the present invention can maintain a state of being immersed in seawater for a long period of at least 20 years. In particular, rust on the exterior can be prevented unless electrically significant moisture penetration occurs.

[0093] Although embodiments of the present invention have been described above with reference to the attached drawings, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims. Explanation of the symbols

[0094] 100: External case 300: Flange

Claims

Claim 1 A field recovery connection box comprising: an outer case in the shape of a hollow tube; and flanges configured to be coupled to each end of the outer case; wherein the flanges comprise: a first part in the shape of a plate disposed inside the outer case and having a first through hole formed therein; a second part comprising a base portion in the shape of a tube having a second through hole and a first ring portion disposed at one end of the base portion and facing the first part; and a third part in the shape of a horn having a volume that can be disposed inside the second through hole and having a third through hole, and which is housed inside the second through hole by the first part; wherein the second part comprises: a second ring portion disposed in the middle part of the base portion and coupled to the outer case; and a third ring portion disposed at the other end of the base portion and coupled to a bending adjuster configured to adjust the degree of bending of a submarine cable. Claim 2 In claim 1, the external case comprises first to fourth external cases joined together, the second external case is disposed below the first external case, the fourth external case is disposed below the third external case, and the third external case is disposed on one side of the first external case, forming a field recovery connection box. Claim 3 In claim 1, the field repair connection box, wherein the first part and the first ring part are joined through a plurality of fastening means. Claim 4 In claim 1, when the first part is coupled to the first ring part, the third part is disposed inside one end of the base part, and the thickness of one end of the base part becomes thicker as it goes from one end of the base part to the other end, field repair connection box. Claim 5 In claim 4, when the first part is coupled to the first ring part, the third part is sealed inside the second through hole, and a predetermined gap is formed between the third part and the base part, forming a field repair connection. Claim 6 In claim 1, the base portion has at least one injection hole connected to the second through hole and into which a liquid compound can be injected, and the liquid compound is for improving the bonding strength with a plurality of steel wires of the submarine cable, field repair connection. Claim 7 delete Claim 8 In claim 1, the width or diameter of the second ring portion is larger than the width or diameter of the first part and the first ring portion, forming a field repair connection. Claim 9 It comprises: a cylindrical outer case; and a flange configured to be coupled to openings at both ends of the outer case; wherein the flange comprises a disc, a cylindrical part, and a truncated cone for fixing a plurality of steel wires of a submarine cable, wherein each of the disc, the cylindrical part, and the truncated cone has a through hole into which the submarine cable can be inserted, and the truncated cone is positioned inside the through hole of the cylindrical part through an opening on one side of the cylindrical part, and the disc is positioned to block the opening on one side of the cylindrical part, and a portion of the plurality of steel wires of the submarine cable is configured to be inserted between the inner surface of the cylindrical part defining the through hole of the cylindrical part and the outer surface of the truncated cone, and another portion of the plurality of steel wires of the submarine cable is configured to be inserted between one end of the cylindrical part and the disc, and the flange comprises: a first ring portion positioned on the side of the opening on one side of the cylindrical part; and a second ring portion positioned between the opening on one side of the cylindrical part and the other opening on the cylindrical part and coupled to the outer case. A field recovery connection comprising: a third ring portion coupled to a bending adjuster disposed on the other side of the opening of the cylindrical portion and configured to adjust the degree of bending of the submarine cable; and Claim 10 In claim 9, the external case comprises first to fourth external cases having a semi-cylindrical shape, the second external case is disposed below the first external case, the fourth external case is disposed below the third external case, and the third external case is disposed on one side of the first external case, forming a field recovery connection box. Claim 11 In claim 9, the field repair connection is formed such that one end of the disc and the cylindrical part are joined through a plurality of fastening means. Claim 12 In claim 9, the thickness of the cylindrical portion surrounding the truncated cone becomes thicker as it goes from one side opening of the cylindrical portion to the other side opening, forming a field repair connection. Claim 13 In claim 9, the cylindrical part has at least one injection hole connected to the through hole of the cylindrical part and into which a liquid compound can be injected, and the liquid compound is for improving the bonding strength with a plurality of steel wires of the submarine cable, field repair connection. Claim 14 delete Claim 15 In claim 9, the diameter of the second ring portion is larger than the diameter of the first ring portion, for the field repair connection. Claim 16 A method for securing a submarine cable comprising a plurality of steel wires and an outer sheath layer surrounding the plurality of steel wires to a field recovery junction box of claim 1, comprising: removing the outer sheath layer at the end of the submarine cable to expose the plurality of steel wires to the outside; passing the submarine cable through a second through-hole of the second part and then bending the plurality of steel wires outward; passing the submarine cable through a third through-hole of the third part and then inserting the third part into the second through-hole so that the plurality of steel wires are sandwiched between the second part and the third part; passing the submarine cable through a first through-hole of the first part and then pressing the first part toward the first ring portion of the second part; joining the first part and the first ring portion through a fastening means to bring the first part as close as possible to the first ring portion so that the plurality of steel wires are sandwiched between the first part and the first ring portion; and the plurality of steel wires exposed to the outside from the plurality of steel wires sandwiched between the first part and the first ring portion. A method for securing a submarine cable to a field recovery junction box, comprising: a step of cutting off the ends; a step of injecting and curing a liquid compound to improve the bonding strength with a plurality of steel wires of the submarine cable into an injection hole connected to a second through hole of the base part; and a step of placing a cover plate to block the gap between the first through hole of the first part and the submarine cable, and between the other end of the second part and the submarine cable. Claim 17 delete

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