Submarine cable bend restrictor

Abstract

The present invention relates to a submarine cable bend restrictor and, more specifically, to a submarine cable bend restrictor capable of withstanding stress generated by a submarine cable load or the like. The submarine cable bend restrictor according to the present invention may comprise one adapter flange and a plurality of bend restrictor fasteners fastened to each other so that a submarine cable is introduced into a through-hole. One end of the adapter flange may be fastened to a field restoration connection box, and the other end thereof may be fastened to the bend restrictor fastener at the first location. The front end of the bend restrictor fastener at the first location may be fastened to the adapter flange. The front and rear ends of the adjacent bend restrictor fasteners may be fastened to each other, respectively. The adapter flange and each bend restrictor fastener may be fastened at a predetermined clearance such that a predetermined angle of rotation is possible.

Description

Bending limit device for submarine cables

[0001] The present invention relates to a bending limiting device for submarine cables, and more specifically, to a bending limiting device for submarine cables capable of withstanding stress caused by the load of the submarine cable, etc.

[0002] Generally, submarine cables require vertical installation between wind towers or horizontal installation for power supply.

[0003] Submarine cables for power or communication transmission are connected by connecting intermediate and terminal points.

[0004] The field repair joint method is primarily employed for connecting submarine cables; however, when a submarine cable connected to a field repair joint is installed in the sea after work on land, a load is generated at both ends of the joint due to the cable's own weight.

[0005] At this time, to prevent the cable from coming loose due to the load, it is secured to the junction box using a restraining device.

[0006] Unlike surface cables, submarine cables are difficult to install junction boxes for cable connection, so they are continuously produced on cable laying vessels for long-distance installation. In particular, considering the cable bending radius that inevitably occurs during installation, the manufacturer specifies a Minimum Bending Radius according to each cable specification, and at this time, a Bend Restrictor, which is a device that maintains the minimum bending radius of the cable, is installed at both ends of the junction box.

[0007] The bend restrictor is a key component of field repair joints that can be installed at sea in the event of a cable short circuit; it is an essential part required for moving and installing cables on the water surface after repairing the connection at the site (on a ship at sea) following a submarine cable accident.

[0008] Therefore, although the degree of bending should be minimized during the process of bringing in submarine cables—that is, the work should be carried out in a horizontal form as much as possible—it is practically difficult to satisfy this in a limited space. Furthermore, when installed after connecting the Field Repair Joint (FRJ), the device must withstand the stress caused by the cable's own weight underwater, but conventional anti-bending devices do not have sufficient strength to withstand the stress caused by the cable's own weight, leading to problems such as the repair of the released cable.

[0009] [Prior Art Literature]

[0010] [Patent Literature]

[0011] (Patent Document 1) Republic of Korea Published Patent 10-2024-0133648

[0012] (Patent Document 2) Republic of Korea Registered Patent 10-2636814

[0013] (Patent Document 3) Republic of Korea Registered Patent 10-2133932

[0014] The technical problem that the present invention aims to solve is to propose a bending limiting device for submarine cables capable of withstanding stress caused by the self-weight of the submarine cable during installation after connection to a field recovery junction box (FRJ).

[0015] In addition, since the stress values ​​are designed considering the cable weight and buoyancy according to the cable depth, we propose a bending limiting device for submarine cables that can pass installation and handling tests in accordance with the corresponding specifications.

[0016] The problems to be solved by the present invention are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.

[0017] A bending limiting device for a submarine cable according to the present invention for solving the above-mentioned problem may be characterized by a single adapter flange and a plurality of bending limiting fasteners being connected to each other so that a submarine cable is fed into a penetrating hole, one end of the adapter flange being connected to a field repair connection box and the other end being connected to a first positioned bending limiting fastener, the front end of the first positioned bending limiting fastener being connected to the adapter flange, and adjacent bending limiting fasteners being connected to each other at their front and rear ends, respectively, and being connected such that the adapter flange and the bending limiting fasteners have a predetermined clearance when connected, allowing for rotation by a predetermined angle.

[0018] Here, the adapter flange may be formed by integrally combining a connection box end flange that is connected to the field repair connection box, a binding end flange that can be connected to the first positioned bending limiting binding member, and a flange connection part that connects the connection box end flange and the binding end flange.

[0019] Here, the other end of the flange connection part and one end of the binding end flange can be connected to each other with a predetermined radius of curvature R1.

[0020] Here, the bending limiting fastener may be formed such that one side has a relatively large radius, the other side has a relatively small radius, and a fastener connecting part connecting the large diameter fastener and the small diameter fastener are integrated with each other.

[0021] Here, the large diameter fastener is connected by inserting the small diameter fastener of an adjacent bending limit fastener, and the inner shape of the large diameter fastener can be formed to have the outer shape of the small diameter fastener so that the small diameter fastener can be seated with a gap.

[0022] Here, the interior of the large diameter binding member may have a radius of curvature R2 formed at the part in contact with the small diameter binding member, and the outer part of the small diameter binding member may have a radius of curvature R3 formed at the part in contact with the radius of curvature R2 of the large diameter binding member.

[0023] Here, it is preferable that the radius of curvature R2 is the same as the radius of curvature R3.

[0024] Here, the inner side of the large diameter binding member may be formed as a straight inner wall with a vertical wall structure, and the other side of the small diameter binding member may be formed as an inclined outer wall that slopes toward the outside.

[0025] Here, the large diameter connecting member of the first positioned bending limit connecting member is connected with the connecting member end flange of the adapter flange having a predetermined clearance by being drawn inward, and the inner shape of the large diameter connecting member of the first positioned bending limit connecting member can be formed to have the outer shape of the connecting member end flange so that the connecting member end flange can be seated.

[0026] According to the above configuration, it is possible to propose a bending limiting device for a submarine cable capable of withstanding stress caused by the self-weight of the submarine cable when installed after connecting to a field recovery junction box (FRJ).

[0027] In addition, since the stress values ​​are designed considering the cable weight and buoyancy according to the cable depth, a bending limiting device for submarine cables that can pass installation and handling tests according to the corresponding specifications can be proposed.

[0028] However, the effects of the present invention are not limited to the effects described above, and may be extended in various ways without departing from the spirit and scope of the present invention.

[0029] FIG. 1 is a combined structure diagram of a bending limiting device for submarine cables and a junction box for on-site restoration according to the present invention.

[0030] Figure 2 shows a diagram of a submarine cable connected using a bending limiting device according to the present invention.

[0031] FIG. 3 is a structural diagram of an adapter flange of a bending limiting device for a submarine cable according to the present invention.

[0032] FIG. 4 is a structural diagram of a bending limiting fastener of a bending limiting device for a submarine cable according to the present invention.

[0033] Figure 5 is the result of a stress analysis according to the shape of the bending limiting device for a submarine cable according to the present invention.

[0034] Figure 6 shows the displacement results according to the shape of the bending limiting device for a submarine cable according to the present invention.

[0035] Hereinafter, a bending limiting device for a submarine cable according to the present invention will be described in detail with reference to the drawings.

[0036] The detailed description of specific embodiments illustrated in the attached drawings is to be read in conjunction with the accompanying drawings, and the drawings are considered to be part of the description of the entire invention. References to directions or orientations are for convenience of explanation only and are not intended to limit the scope of the invention in any way.

[0037] It should be noted that when assigning reference numerals to the components of each drawing, the same components are assigned the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the present invention, if it is determined that a detailed description of related known components or functions could obscure the essence of the invention, such detailed description is omitted.

[0038] FIG. 1 is a combined structure diagram of a bending limiting device for submarine cables and a junction box for on-site restoration according to the present invention.

[0039] Generally, when connecting submarine cables, the submarine cables (120a, 120b) are connected to a field repair joint (110) and then installed on the seabed.

[0040] When installing a submarine cable on the seabed, a load is generated at both ends of the field recovery connection box (110) due to the weight of the cable, and the submarine cable may detach due to the load. To prevent this, the cable is fixed to the field recovery connection box (110) using a device with a restraining force.

[0041] In the case of submarine cables (210a, 210b), unlike above-ground ultra-high voltage cables, it is difficult to install junction boxes for cable connection, so they are continuously produced on cable laying vessels for long-distance installation, and the manufacturer specifies a minimum bending radius according to each cable specification, taking into account the cable bending radius that inevitably occurs during installation.

[0042] At this time, in order to maintain the minimum bending radius of the submarine cable (120a, 120b) at both ends of the field recovery connection box (110), a bend limiting device (Bend Restrictor, 130a, 130b) such as the present invention is used.

[0043] These field recovery connection boxes (110) must be able to withstand sufficient stress caused by the weight of the cable in the sea when installed after connection, and the stress value must be designed considering the cable weight and buoyancy according to the cable depth.

[0044] In addition, according to the standards, a handling test must be conducted during installation, and the cable length and load applied to both ends must be calculated; the actual installation must then proceed by applying the required number of load-bearing cycles.

[0045] The bending limiting device (130a, 130b) of the present invention is designed to withstand stress caused by loads on both ends of the submarine cable (120a, 120b) when a cable installed in the sea fails, as described above through the test, and can perform the role of a device that prevents the shear of force generated in the submarine cable (120a, 120b).

[0046] Figure 2 shows a diagram of a submarine cable connected using a bending limiting device according to the present invention.

[0047] As illustrated in FIG. 2, the bending limiting device (130) according to the present invention has a shape in which an adapter flange (210) with an internal opening and a plurality of bending limiting fasteners (220) are connected to each other, and a submarine cable (120) is inserted into the internal opening.

[0048] A plurality of bending limiting fasteners (220) are connected at their beginning and end and have a certain amount of clearance while having flexibility, thereby limiting excessive bending of the submarine cable (120) as it bends according to the load of the submarine cable (120).

[0049] FIG. 3 is a structural diagram of an adapter flange of a bending limiting device for a submarine cable according to the present invention.

[0050] Figure 3 (A) is a perspective view of the adapter flange (210), and (B) is a cross-sectional view of the adapter flange (210).

[0051] Referring to FIG. 3, the adapter flange (210) enables connection between the field recovery connection box (110) and the bending limiting fastener (220) at the tip, and allows for flexibility during connection.

[0052] The adapter flange (210) may be formed by integrating a connection box end flange (211) that can be connected to a field recovery connection box (110), a connection end flange (212) that can be connected to a bending limiting connection member (220) at the tip, and a flange connection part (213) that connects the connection box end flange (211) and the connection end flange (212) to each other, and the interior may have a through hole so that a submarine cable (120) can be inserted through it.

[0053] One end of the flange connection part (213) is connected to the connection end flange (211), and the other end is connected to the binding end flange (212).

[0054] The other end of the flange connection part (213) and the one end of the binding end flange (212) are connected to each other and formed to have a predetermined radius of curvature (R1).

[0055] This radius of curvature (R1) is a very useful design element for meeting design specifications, such as stress due to bending limitation and displacement limitation due to load of the submarine cable (120), when connected with the bending limitation fastener (220).

[0056] FIG. 4 is a structural diagram of a bending limiting fastener of a bending limiting device for a submarine cable according to the present invention.

[0057] (A) of FIG. 4 is a perspective view of a bending limiting fastener (220), and (B) is a cross-sectional view of a bending limiting fastener (220).

[0058] Referring to FIG. 4, the bending limiting fastener (220) allows for connection with the adapter flange (210) and connection between the bending limiting fasteners (220) at the first stage, and enables fluidity due to internal clearance during connection.

[0059] The bending limiting fastener (220) may be formed by integrating a large-diameter fastener (221) with a relatively large radius on one side, a small-diameter fastener (222) with a relatively small radius on the other side, and a fastener connecting part (223) connecting the large-diameter fastener (221) and the small-diameter fastener (222) to each other, and may have a through hole so that a submarine cable (120) can be inserted through it.

[0060] The large diameter binding member (221) has the small diameter binding member (222) of the adjacent bending limit binding member (220) inserted and bound inside, and the small diameter binding member (221) can be bound while being inserted into the inside of the large diameter binding member (221) of the adjacent bending limit binding member (220).

[0061] Meanwhile, the large diameter connecting member (221) of the first stage bending limit connecting member (220) can be connected with the connecting member end flange (212) of the adapter flange (210) retracted inward.

[0062] The interior of the large diameter binding member (221) can be formed such that one side of the inner diameter has the outer shape of the binding member connecting part (223) and the other side has the outer shape of the small diameter binding member (222) so that the small diameter binding member (222) can be seated.

[0063] The inner part of the large diameter binding member (221) has a radius of curvature (R2) formed at the part in contact with the small diameter binding member (222), and the outer part of the small diameter binding member (222) has a radius of curvature (R3) formed at the part in contact with the radius of curvature (R2) of the large diameter binding member (221).

[0064] Preferably, in order to maintain the stress caused by the submarine cable and the displacement due to the weight of the submarine cable at the design value, the radius of curvature R2 and the radius of curvature R3 may be the same, and the radius of curvature R1 of the adapter flange (210) may also be the same as the radius of curvature R2 and R3.

[0065] Additionally, to limit bending and displacement of the submarine cable (120), the inner side of the large diameter binding member (221) may be formed as a straight inner wall (224) with a vertical wall structure, and the outer side of the small diameter binding member (222) may be formed as an inclined outer wall (225) that slopes toward the outside.

[0066] These radii of curvature (R1, R2, R3), the straight inner wall (224), and the inclined outer wall (225) are very useful design elements for meeting design specifications such as stress due to bending limitation and displacement limitation due to load of the submarine cable (120) when connecting between bending limiting fasteners (220).

[0067] Figure 5 is the result of a stress analysis according to the shape of the bending limiting device for a submarine cable according to the present invention.

[0068] Figure 5 is the result of a stress simulation using the nonlinear specialized software Marc Solver, considering the self-weight of the submarine cable, the self-weight of the bending limiting device, and loads caused by additional external elements based on the design values ​​of Figures 1 to 4 described above.

[0069] As a result of the simulation, it was confirmed that a maximum stress occurs at the connection point between the small diameter connection member (222) of the first bending limiting connection member (220) and the large diameter connection member (221) of the second bending limiting connection member (220) in the bending limiting device (130), and that this maximum stress value is within the range of the design safety value.

[0070] Figure 6 shows the displacement results according to the shape of the bending limiting device for a submarine cable according to the present invention.

[0071] Figure 6 is the result of a displacement simulation of a submarine cable using the nonlinear specialized software Marc Solver, taking into account the self-weight of the submarine cable, the self-weight of the bending limiting device, and loads caused by additional external elements based on the design values ​​of Figures 1 to 4 described above.

[0072] Here, 130A is the bending displacement when the self-weight of the bending limiting device (130) and gravity are applied, and 130B is the simulation result representing the bending displacement when the self-weight of the bending limiting device (130), the self-weight of the submarine cable (120), and gravity are applied.

[0073] It was confirmed that the bending displacement in the 130A and 130B states is D with respect to the X-axis, and that this displacement D is within the design displacement criteria.

[0074] Although the present invention, as described in detail above, has been explained based on limited embodiments and drawings, the present invention is not limited thereto, and various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the patent claims by those skilled in the art to which the present invention belongs.

[0075] However, it is evident that such simple modifications and variations cannot fall outside the scope of the rights of the present invention.

[0076] The features, structures, effects, etc. described in the embodiments above are included in one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified and implemented in other embodiments by a person skilled in the art to which the embodiments belong. Therefore, details regarding such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0077] [Explanation of the symbol]

[0078] 110: Field recovery connection

[0079] 120, 120a, 120b: Submarine cable

[0080] 130, 130a, 130b: Bending limit device

[0081] 210 : Adapter flange

[0082] 220 : Bending limit fastener

Claims

1. A single adapter flange and multiple bend limiting fasteners are connected to each other so that a submarine cable is fed into the penetrating hole, and One end of the above adapter flange is connected to a field recovery junction box, and the other end is connected to a first-positioned bending limiter, and The first bending limiting fastener is connected to the adapter flange at its leading end, and adjacent bending limiting fasteners are connected to each other at their leading and trailing ends, respectively. A bending limiting device for submarine cables, wherein the adapter flange and the bending limiting fastener are each connected with a predetermined clearance so as to allow rotation by a predetermined angle.

2. In Paragraph 1, A bending limiting device for a submarine cable, wherein the adapter flange is formed by integrating a connection box end flange that is connected to the field recovery connection box, a binding end flange that can be connected to the first positioned bending limiting binding member, and a flange connection portion that connects the connection box end flange and the binding end flange.

3. In Paragraph 2, A bending limiting device for a submarine cable, wherein the other end of the above-mentioned flange connection part and one end of the above-mentioned binding end flange are connected to each other with a predetermined radius of curvature R1.

4. In Paragraph 1, A bending limiting device for a submarine cable, wherein the above bending limiting member is formed by integrating a large-diameter member with a relatively large radius on one side, a small-diameter member with a relatively small radius on the other side, and a member connecting part that connects the large-diameter member and the small-diameter member.

5. In Paragraph 4, The above large diameter fastener is fastened by inserting the small diameter fastener of an adjacent bending limit fastener, and A bending limiting device for a submarine cable, wherein the inner shape of the large-diameter binding member is formed to have the outer shape of the small-diameter binding member so that the small-diameter binding member can be seated with a gap.

6. In Paragraph 4, The interior of the above-mentioned large-diameter binding member has a radius of curvature R2 formed at the part in contact with the above-mentioned small-diameter binding member, and A bending limiting device for submarine cables, wherein the outer portion of the small diameter binding member has a radius of curvature R3 formed at the portion in contact with the radius of curvature R2 of the large diameter binding member.

7. In Paragraph 6, The above radius of curvature R2 is the same as the above radius of curvature R3, a bending limiting device for submarine cables.

8. In Paragraph 4, The inner other side of the above-mentioned large-diameter binding member is formed as a straight inner wall with a vertical wall structure, and A bending limiting device for submarine cables, wherein the other side of the above-mentioned small-diameter binding member is formed as an inclined outer wall that slopes toward the outside.

9. In Paragraph 4, The large diameter fastener of the first positioned bending limit fastener is fastened with the fastener end flange of the adapter flange being drawn inward and having a predetermined clearance, and A bending limiting device for a submarine cable, wherein the inner shape of the large diameter binding member of the first positioned bending limiting binding member is formed to have the outer shape of the binding member end flange so that the binding member end flange can be seated.

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