Submarine cable traction test method and system

Abstract

The invention relates to the technical field of submarine cable testing, in particular to a submarine cable traction testing method and system. According to the submarine cable traction test method, for a submarine cable which is sleeved with a plurality of ball resistance reduction modules to reduce traction friction resistance, a section of cable guide pipe placed on the ground is used for carrying out traction test; and a friction coefficient equation corresponding to the moment is constructed based on the corresponding out-of-pipe ball load, in-pipe ball load, submarine cable head end tension and submarine cable tail end tension when each ball resistance reduction module leaves the fairlead, and then a friction coefficient model is constructed according to the corresponding friction coefficient equation when each ball resistance reduction module leaves the fairlead. And finally, solving the friction coefficient model by using a least square method to obtain an in-pipe friction coefficient as a traction test result, so that a standardized measurement means is provided for the equivalent friction coefficient between the submarine cable and the fairlead after the drag reduction module is additionally arranged, and the solving result of the in-pipe friction coefficient is closer to the optimal estimation of real physical parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of submarine cable testing, and particularly to a submarine cable traction testing method and system. Background Art

[0002] Currently, in the power transmission system of an offshore wind farm, the submarine cable responsible for power transmission needs to achieve the sea-land transition through a dike-piercing project. Most of the existing dike-piercing projects adopt a non-excavation cable guiding technology, that is, a submarine cable protection steel pipe is buried along a predetermined cable guiding path as a cable guiding pipe. The cable guiding pipe penetrates into the seabed at an inclined angle from the mud entry point in the open sea, passes through the sea dike, and emerges from the ground at the onshore booster station to form a closed submarine cable channel. During dike-piercing, a traction device is used to tow the submarine cable along the inside of the cable guiding pipe to a predetermined position.

[0003] Technical practice shows that the frictional resistance between the cable guiding pipe and the submarine cable in the submarine cable dike-piercing project is a key physical parameter for protecting the submarine cable and designing the traction device. To protect the submarine cable, the prior art installs a drag reduction module with a low friction coefficient on the surface of the submarine cable to reduce the frictional loss between the submarine cable and the cable guiding pipe. However, there is a lack of a standardized measurement method for the equivalent friction coefficient between the submarine cable with the drag reduction module installed and the cable guiding pipe, resulting in difficulty in calculating the optimal pulling force for towing the submarine cable and being unable to provide reliable data for the submarine cable dike-piercing. Summary of the Invention

[0004] The present invention aims to provide a submarine cable traction testing method and system to provide a standardized measurement method for the equivalent friction coefficient between the submarine cable with a drag reduction module installed and the cable guiding pipe.

[0005] To achieve the above object, in a first aspect of the present invention, a submarine cable traction testing method is provided, which is applied to the traction testing of a submarine cable. The submarine cable is sleeved with a plurality of ball drag reduction modules and placed inside a cable guiding pipe. The submarine cable traction testing method includes: towing the submarine cable, and then when each of the ball drag reduction modules leaves the cable guiding pipe, obtaining the external ball load, the internal ball load, the pulling force at the head end of the submarine cable, and the pulling force at the tail end of the submarine cable; constructing a friction coefficient model based on the external ball load, the internal ball load, the pulling force at the head end of the submarine cable, and the pulling force at the tail end of the submarine cable corresponding to when each of the ball drag reduction modules leaves the cable guiding pipe; obtaining the internal friction coefficient based on the friction coefficient model, and taking the internal friction coefficient as the test result.

[0006] For the above-mentioned submarine cable traction test method, for a submarine cable sleeved with a number of ball friction reduction modules to reduce the traction friction resistance, a cable guide pipe placed on the ground is used for traction test, and a corresponding friction coefficient equation at this moment is constructed based on the external pipe ball load, internal pipe ball load, submarine cable head tension and submarine cable end tension corresponding to each ball friction reduction module when it leaves the cable guide pipe. Then, a friction coefficient model is constructed according to the friction coefficient equations corresponding to each ball friction reduction module when it leaves the cable guide pipe. Finally, the least square method is used to solve the friction coefficient model to obtain the in-pipe friction coefficient as the traction test result, providing a standardized measurement method for the equivalent friction coefficient between the submarine cable and the cable guide pipe after installing the friction reduction module. In addition, the friction coefficient model solves the in-pipe friction coefficient by comprehensively considering the load conditions of each ball friction reduction module when it leaves the cable guide pipe. Compared with obtaining single data and using a single equation to solve, it can effectively reduce the influence of measurement outliers, make the calculation result of the in-pipe friction coefficient closer to the optimal estimate of the true physical parameters, thereby reducing random errors and improving the accuracy of the in-pipe friction coefficient test result.

[0007] Preferably, before towing the submarine cable and obtaining the external pipe ball load, internal pipe ball load, submarine cable head tension and submarine cable end tension when each ball friction reduction module leaves the cable guide pipe, it includes:

[0008] For any of the ball friction reduction modules, obtain the initial vertical load of the ball friction reduction module, and then obtain the corresponding initial vertical load for each ball friction reduction module;

[0009] Towing the submarine cable and obtaining the external pipe ball load, internal pipe ball load, submarine cable head tension and submarine cable end tension when each ball friction reduction module leaves the cable guide pipe includes:

[0010] Based on the initial vertical load corresponding to each ball friction reduction module, obtain the external pipe ball load and the internal pipe ball load.

[0011] Preferably, for any of the ball friction reduction modules, obtaining the initial vertical load of the ball friction reduction module and then obtaining the corresponding initial vertical load for each ball friction reduction module includes:

[0012] For any of the ball friction reduction modules, obtain the weight of the submarine cable borne by the ball friction reduction module and the weight of the ball friction reduction module, and use the weight of the submarine cable and the weight of the ball friction reduction module as the initial vertical load of the ball friction reduction module.

[0013] In the above embodiments, by obtaining the initial vertical load of each ball drag reduction module under the initial static condition, the initial vertical load can be used as the force analysis data during the traction test. Furthermore, during the traction test, based on the initial vertical load corresponding to each ball drag reduction module, the vertical load of all the ball drag reduction modules outside the cable guide pipe is obtained as the external pipe ball load, and the vertical load of all the ball drag reduction modules inside the cable guide pipe is obtained as the internal pipe ball load.

[0014] Preferably, in the construction of the friction coefficient model based on the external pipe ball load, internal pipe ball load, tension at the head end of the submarine cable, and tension at the tail end of the submarine cable corresponding to each ball drag reduction module when it leaves the cable guide pipe, the friction coefficient model is specifically:

[0015]

[0016] Where n is the total number of the several ball drag reduction modules, Ma1 is the internal pipe ball load when the first ball drag reduction module leaves the cable guide pipe, Ma2 is the internal pipe ball load when the second ball drag reduction module leaves the cable guide pipe, Ma n is the internal pipe ball load when the nth ball drag reduction module leaves the cable guide pipe, Mb1 is the external pipe ball load when the first ball drag reduction module leaves the cable guide pipe, Mb2 is the external pipe ball load when the second ball drag reduction module leaves the cable guide pipe, Mb n is the external pipe ball load when the nth ball drag reduction module leaves the cable guide pipe, Fa1 is the tension at the head end of the submarine cable when the first ball drag reduction module leaves the cable guide pipe, Fa2 is the tension at the head end of the submarine cable when the second ball drag reduction module leaves the cable guide pipe, Fa n is the tension at the head end of the submarine cable when the nth ball drag reduction module leaves the cable guide pipe, Fb1 is the tension at the tail end of the submarine cable when the first ball drag reduction module leaves the cable guide pipe, Fb2 is the tension at the tail end of the submarine cable when the second ball drag reduction module leaves the cable guide pipe, Fb n is the tension at the tail end of the submarine cable when the nth ball drag reduction module leaves the cable guide pipe, fa is the internal pipe friction coefficient, and fb is the external pipe friction coefficient.

[0017] In this embodiment, since the process of towing the submarine cable can be approximately equivalent to a uniform linear motion process, it can be analyzed that the total value of the traction force on the submarine cable is equal to the total value of the resistance on the submarine cable, that is, the difference between the tension at the head end of the submarine cable and the tension at the tail end of the submarine cable is equal to the sum of the external pipe friction resistance and the internal pipe friction resistance of the submarine cable. Among them, the external pipe friction resistance on the submarine cable is equal to the external pipe ball load multiplied by the external pipe friction coefficient; the internal pipe friction resistance on the submarine cable is equal to the internal pipe ball load multiplied by the internal pipe friction coefficient.

[0018] It should also be noted that for the convenience of testing, the cable guide pipe in the above-mentioned embodiments is arranged on the ground of the test site. Therefore, when the submarine cable is pulled out of the cable guide pipe, the ball friction reduction module on the submarine cable will contact the test site, thereby generating external friction resistance to hinder the movement of the submarine cable.

[0019] Preferably, the submarine cable traction test method further includes: setting a plurality of groups of test conditions to traction the submarine cable under each group of test conditions and obtaining the corresponding in-pipe friction coefficient under each group of test conditions; solving the mean value based on the in-pipe friction coefficient corresponding to each group of test conditions to obtain the average friction coefficient, and taking the average friction coefficient as the test result.

[0020] In this embodiment, by repeatedly conducting multiple submarine cable traction tests and solving the mean value of the friction coefficients obtained from the multiple traction test results, the random error in a single test is reduced, the influence of measurement outliers is effectively reduced, thereby improving the accuracy and reliability of the obtained test results.

[0021] The second aspect of the present invention provides a submarine cable traction test system, which is applicable to the submarine cable traction test method as described in any one of the first aspects of the present invention and is used for the traction test of the submarine cable. The submarine cable is sleeved with a plurality of ball friction reduction modules and placed in the cable guide pipe. The submarine cable traction test system includes a head-end traction device, a tail-end traction device, a model construction module and a solution module, wherein:

[0022] The head-end traction device is used to traction the submarine cable, and when each ball friction reduction module leaves the cable guide pipe, obtain the head-end tension of the submarine cable;

[0023] The tail-end traction device is used to assist the head-end traction device to traction the submarine cable, and when each ball friction reduction module leaves the cable guide pipe, obtain the tail-end tension of the submarine cable;

[0024] The model construction module is used to obtain the external-ball load and in-pipe ball load when each ball friction reduction module leaves the cable guide pipe, and thus construct a friction coefficient model based on the external-ball load, in-pipe ball load, head-end tension of the submarine cable and tail-end tension of the submarine cable corresponding to when each ball friction reduction module leaves the cable guide pipe;

[0025] The solution module is used to obtain the in-pipe friction coefficient according to the friction coefficient model and take the in-pipe friction coefficient as the test result.

[0026] The above-mentioned submarine cable traction test system implements the submarine cable traction test method described in the first aspect of the present invention. For a submarine cable sleeved with a number of ball friction reduction modules to reduce the traction friction resistance, a cable guide tube placed on the ground is used for traction testing, and a friction coefficient equation corresponding to this moment is constructed based on the external tube ball load, internal tube ball load, submarine cable head tension, and submarine cable end tension corresponding to each ball friction reduction module leaving the cable guide tube. Then, a friction coefficient model is constructed according to the friction coefficient equations corresponding to each ball friction reduction module leaving the cable guide tube. Finally, the least squares method is used to solve the friction coefficient model to obtain the in-tube friction coefficient as the traction test result, providing a standardized measurement method for the equivalent friction coefficient between the submarine cable and the cable guide tube after installing the friction reduction module. In addition, the friction coefficient model solves the in-tube friction coefficient by comprehensively considering the load conditions when each ball friction reduction module leaves the cable guide tube. Compared with obtaining single data and using a single equation to solve, it can effectively reduce the influence of measurement outliers, make the calculation result of the in-tube friction coefficient closer to the optimal estimate of the true physical parameters, thereby reducing random errors and improving the accuracy of the in-tube friction coefficient test result.

[0027] It should be noted that, in order to improve the accuracy of the test results, in some possible implementation manners, it is necessary to repeat the submarine cable traction test on the same section of the test submarine cable multiple times. During the process of the end of the test submarine cable being dragged by the traction force multiple times, it is easy to exceed its load fatigue limit and break.

[0028] To solve the above technical problems, in a preferred implementation manner, it further includes a traction protection module and a number of prestressed steel cables, where: the traction protection module is sleeved on the head end of the submarine cable and is connected to the head end traction device and the galvanized copper wire of the submarine cable; each prestressed steel cable passes through a number of ball friction reduction modules and is connected to the traction protection module.

[0029] In this implementation manner, the traction protection module is connected to the galvanized copper wire of the submarine cable. The galvanized copper wire of the submarine cable serves as a stress-bearing member to share the traction load at the end of the submarine cable, reducing the stress load at the end of the submarine cable. At the same time, the prestressed steel cable is used as an auxiliary stress-bearing member. While sharing the traction load at the end of the submarine cable, the prestressed steel cable distributes the traction load at the end of the submarine cable to each ball friction reduction module distributed along the length direction of the submarine cable, thereby preventing the end of the submarine cable from exceeding its load fatigue limit and breaking during multiple traction tests, so as to enhance the protection effect of the traction test system on the submarine cable.

[0030] Furthermore, using this submarine cable traction test system can perform multiple repeated tests on the submarine cable without damaging the submarine cable, improving the test efficiency of the submarine cable traction test and avoiding errors in the test results caused by replacing the submarine cable, thereby improving the accuracy of the submarine cable traction test.

[0031] Preferably, the traction protection module includes a pulling sub-module, a load sharing sub-module, and a circular sleeve; the pulling sub-module and the circular sleeve are respectively connected to the load sharing sub-module, and the load sharing sub-module is provided with a plurality of uniformly distributed through holes, where:

[0032] The circular sleeve is sleeved on the head end of the submarine cable;

[0033] After the galvanized copper wires of the submarine cable are grouped and stranded into a plurality of groups of galvanized wire ropes, each group of the galvanized wire ropes passes through the corresponding through hole and is bound and connected to the load sharing sub-module, so that a plurality of groups of the galvanized wire ropes are bound and connected to the load sharing sub-module;

[0034] The pulling sub-module is connected to the head end traction device and the prestressed steel cable.

[0035] In this embodiment, each group of galvanized copper wires is stranded and bound into a group of galvanized wire ropes. The galvanized wire ropes are tougher and more resistant to breakage than single galvanized copper wires, improving the structural reliability of the submarine cable traction test system. In addition, the through holes in the load sharing sub-module are evenly distributed in a circle, enabling the galvanized wire ropes to bear force synergistically and evenly share the traction load at the end of the submarine cable, improving the effect of the galvanized wire ropes sharing the component force of the traction force at the end of the submarine cable. The circular sleeve is tightly sleeved on the end of the submarine cable, enabling the galvanized copper wires to be evenly stressed and bear force synergistically.

[0036] Preferably, each group of the galvanized wire ropes is provided with a strain gauge for detecting the stress condition of the corresponding galvanized wire rope.

[0037] In this embodiment, the stress condition of the galvanized copper wires in the submarine cable is detected by the strain gauge, so as to judge whether the galvanized copper wires of the submarine cable are evenly stressed and cooperate with the prestressed steel cable to bear force, enabling the tester to adjust the test system in time according to the strain gauge data, improving the reliability of the test system and the accuracy of the test results.

[0038] Preferably, the traction protection module includes a sleeve part, a traction part, a fastening part, and a transition part; the sleeve part is connected to the transition part, and the transition part is connected to the traction part, where:

[0039] The sleeve part is sleeved on the head end of the submarine cable and is used to connect the prestressed steel cable;

[0040] The transition part includes a strip hole. After the galvanized copper wires of the submarine cable pass through the strip hole, they are clamped on the outer side surface of the sleeve part through the cooperation of the sleeve part and the fastening part;

[0041] The traction part is connected to the head end traction device.

[0042] Specifically, the width of the strip-shaped hole is slightly larger than the diameter of the galvanized copper wire.

[0043] In this embodiment, the fastening portion is installed on the outer side surface of the sleeve portion, so as to cooperate with the sleeve portion to clamp the part of the galvanized copper wire that is closely attached to the outer side surface of the sleeve portion, thereby ensuring the firmness of the connection between the traction portion and the galvanized copper wire. Among them, the galvanized copper wire passes through the strip-shaped hole and then closely adheres to the outer side surface of the sleeve portion. In addition, the galvanized copper wires passing through the same strip-shaped hole in the transition portion are closely and neatly arranged, and can evenly share the traction load; the width of the strip-shaped hole is slightly larger than the diameter of the galvanized copper wire, which can limit the galvanized copper wire passing through the strip-shaped hole and prevent the galvanized copper wire from being stacked or disordered. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic cross-sectional view of an undersea cable provided by an embodiment of the present invention;

[0045] Figure 2 is a schematic flow chart of a method for testing the traction of an undersea cable provided by an embodiment of the present invention;

[0046] Figure 3 is a schematic diagram of the initial vertical load received by a ball bearing drag reduction module provided by an embodiment of the present invention;

[0047] Figure 4 is a data chart of the tension at the head end and the tension at the tail end of an undersea cable provided by an embodiment of the present invention;

[0048] Figure 5 is a schematic structural diagram of an undersea cable traction test system provided by an embodiment of the present invention;

[0049] Figure 6 is a schematic structural diagram of a traction protection module provided by an embodiment of the present invention;

[0050] Figure 7 is a schematic structural diagram of another traction protection module provided by an embodiment of the present invention;

[0051] Figure 8 is a schematic structural diagram of another traction protection module provided by an embodiment of the present invention;

[0052] Figure 9 is a side view of another traction protection module provided by an embodiment of the present invention;

[0053] Wherein: 1. Ball bearing drag reduction module; 2. Cable guide pipe; 3. Submarine cable; 4. Traction protection module; 5. Prestressed steel cable; 6. First tension sensor; 7. Second tension sensor; 8. Loading connector; 9. Head end traction device; 10. Tail end traction device; 11. Sleeve part; 12. Traction part; 13. Fastening part; 14. Transition part; 15. Strip hole; 16. Load equalizing sub-module; 17. Pulling sub-module; 18. Perforation; 19. Round sleeve ring; 20. Strain gauge; A1. Water-blocking conductor; A2. Conductor shield; A3. XLPE insulation; A4. Insulation shield; A5. Semiconductor water-blocking tape; A6. Alloy lead sheath; A7. Polyethylene (PE) sheath; A8. Filler strip; A9. Optical unit; A10. Tape; A11. Inner cushion layer; A12. Galvanized copper wire; A13. Outer covering layer. Detailed implementation mode

[0054] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that the following detailed descriptions are all exemplary descriptions, aiming to provide further detailed descriptions of the present invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the description of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description, claims and drawings of this application are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description, claims or drawings of this application are used to distinguish different objects and are not used to describe a specific order.

[0055] It should be understood that although the steps in the flowchart of the drawings are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit and can be executed in other orders. Moreover, at least some of the steps in the flowchart of the drawings may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or sub-steps or stages of other steps.

[0056] At present, in the power transmission system of an offshore wind farm, the submarine cable responsible for power transmission needs to achieve the land-sea transition through a dike-piercing project. Most of the existing dike-piercing projects adopt the non-excavation cable guiding technology, that is, a submarine cable protection steel pipe is buried along the predetermined cable guiding path as a cable guiding pipe. The cable guiding pipe penetrates into the seabed at an inclined angle from the mud entry point in the open sea, passes through the sea dike, and emerges from the ground at the onshore booster station, forming a closed submarine cable channel. When piercing the dike, a traction device is used to tow the submarine cable along the inside of the cable guiding pipe to the predetermined position. As Figure 1 shown, the existing submarine cable structure includes a water conductor A1, a conductor shield A2, an XLPE insulation A3, an insulation shield A4, a semiconductive water-resistant tape A5, an alloy lead sheath A6, a polyethylene (PE) sheath A7, a filling strip A8, an optical unit A9, a tape A10, an inner cushion layer A11, galvanized copper wires A12, and an outer covering layer A13.

[0057] Technical practice shows that the frictional resistance between the cable guiding pipe and the submarine cable in the submarine cable dike-piercing project is a key physical parameter for protecting the submarine cable and designing the traction device. To protect the submarine cable, the prior art installs a drag reduction module with a low friction coefficient on the surface of the submarine cable to reduce the frictional loss between the submarine cable and the cable guiding pipe. However, there is a lack of a standardized measurement method for the equivalent friction coefficient between the submarine cable with the drag reduction module installed and the cable guiding pipe, resulting in difficulty in calculating the optimal pulling force for towing the submarine cable and inability to provide reliable data for the submarine cable dike-piercing.

[0058] To solve the above technical problems, referring to Figure 2 , an embodiment of the present invention provides a method for testing the traction of a submarine cable 3, which is applied to the traction test of the submarine cable 3. The submarine cable 3 is sleeved with a plurality of ball drag reduction modules 1 and placed inside the cable guiding pipe 2. This method for testing the traction of the submarine cable 3 includes:

[0059] S101. Traction the submarine cable 3, and then when each of the ball drag reduction modules 1 leaves the cable guiding pipe 2, obtain the external ball load, the internal ball load, the tension at the head end of the submarine cable 3, and the tension at the tail end of the submarine cable 3.

[0060] S102. Based on the external ball load, the internal ball load, the tension at the head end of the submarine cable 3, and the tension at the tail end of the submarine cable 3 corresponding to when each of the ball drag reduction modules 1 leaves the cable guiding pipe 2, construct a friction coefficient model.

[0061] Specifically, the first tension sensor 6 is used to measure the tension at the head end of the submarine cable 3, and the second tension sensor 7 is used to measure the tension at the tail end of the submarine cable 3. Record the time when the head end traction device 9 and the tail end traction device start to traction the submarine cable 3, the time when the first ball friction reduction module 1 leaves the cable guide tube 2, the time when the second ball friction reduction module 1 leaves the cable guide tube 2, …, the time when the last ball friction reduction module 1 leaves the cable guide tube 2, and the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 detected by the first tension sensor 6 and the second tension sensor 7 corresponding to each time, so as to obtain the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 corresponding to each ball friction reduction module 1 leaving the cable guide tube 2.

[0062] S103. Obtain the in-pipe friction coefficient based on the friction coefficient model, and use the in-pipe friction coefficient as the test result.

[0063] For the submarine cable 3 sleeved with a plurality of ball friction reduction modules 1 to reduce the traction friction resistance, the above-mentioned submarine cable 3 traction test method uses a cable guide tube 2 placed on the ground for traction test, and constructs a friction coefficient equation corresponding to each moment based on the external pipe ball load, the internal pipe ball load, the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 corresponding to each ball friction reduction module 1 leaving the cable guide tube 2. Then, a friction coefficient model is constructed according to the friction coefficient equation corresponding to each ball friction reduction module 1 leaving the cable guide tube 2. Finally, the least squares method is used to solve the friction coefficient model to obtain the in-pipe friction coefficient as the traction test result, providing a standardized measurement method for the equivalent friction coefficient between the submarine cable 3 and the cable guide tube 2 after installing the friction reduction module. In addition, the friction coefficient model solves the in-pipe friction coefficient by comprehensively considering the load conditions when each ball friction reduction module 1 leaves the cable guide tube 2. Compared with obtaining single data and using a single equation to solve, it can effectively reduce the influence of measurement outliers, make the calculation result of the in-pipe friction coefficient closer to the optimal estimate of the true physical parameters, thereby reducing random errors and improving the accuracy of the in-pipe friction coefficient test result.

[0064] Preferably, before the submarine cable 3 is tractioned and the external pipe ball load, the internal pipe ball load, the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 are obtained when each ball friction reduction module 1 leaves the cable guide tube 2, it includes:

[0065] For any ball friction reduction module 1, obtain the initial vertical load of the ball friction reduction module 1, and then obtain the corresponding initial vertical load for each ball friction reduction module 1;

[0066] When the submarine cable 3 is tractioned and the external pipe ball load, the internal pipe ball load, the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 are obtained when each ball friction reduction module 1 leaves the cable guide tube 2, it includes:

[0067] Based on the initial vertical load corresponding to each of the ball friction reduction modules 1, obtain the external pipe ball load and the internal pipe ball load.

[0068] Preferably, for any one of the ball friction reduction modules 1, obtaining the initial vertical load of this ball friction reduction module 1, and further obtaining the initial vertical load corresponding to each of the ball friction reduction modules 1, includes:

[0069] For any one of the ball friction reduction modules 1, obtain the weight of the submarine cable 3 borne by this ball friction reduction module 1 and the weight of the ball friction reduction module 1, and use the weight of the submarine cable 3 and the weight of the ball friction reduction module 1 as the initial vertical load of this ball friction reduction module 1.

[0070] Specifically, calculate the actual vertical load borne by each ball friction reduction module 1 through a computer, and the calculation formula is as follows: A = B + C.

[0071] Wherein, B is the weight of (a section of) the submarine cable 3 borne by the ball friction reduction module 1, and C is the weight of the ball friction reduction module 1 itself. Through the above formula, the actual vertical loads borne by the first, second,..., ninth ball friction reduction modules 1 are calculated to be 144 kg, 207 kg, 264 kg, 264 kg, 267 kg, 217 kg, 214 kg, 264 kg, 332 kg respectively, as Figure 3 shown.

[0072] In the above embodiment, by obtaining the initial vertical load of each ball friction reduction module 1 under the initial static condition, this initial vertical load can be used as the force analysis data during the traction test. Furthermore, during the traction test, based on the initial vertical load corresponding to each of the ball friction reduction modules 1, obtain the vertical load of all the ball friction reduction modules 1 outside the cable guide pipe 2 as the external pipe ball load, and obtain the vertical load of all the ball friction reduction modules 1 inside the cable guide pipe 2 as the internal pipe ball load.

[0073] Preferably, in the construction of the friction coefficient model based on the external pipe ball load, internal pipe ball load, cable head tension at the head end of the submarine cable 3, and cable end tension at the tail end of the submarine cable 3 corresponding to each of the ball friction reduction modules 1 when leaving the cable guide pipe 2, the friction coefficient model is specifically:

[0074]

[0075] Wherein, n is the total number of several ball friction reduction modules 1, Ma1 is the internal pipe ball load when the first ball friction reduction module 1 leaves the cable guide pipe 2, Ma2 is the internal pipe ball load when the second ball friction reduction module 1 leaves the cable guide pipe 2, Ma nLet \(M_{b0}\) be the in - pipe ball load when the \(n\)th ball - resistance - reducing module 1 leaves the fairlead 2, \(M_{b1}\) be the out - of - pipe ball load when the first ball - resistance - reducing module 1 leaves the fairlead 2, \(M_{b2}\) be the out - of - pipe ball load when the second ball - resistance - reducing module 1 leaves the fairlead 2, and \(M_{b}\) n be the out - of - pipe ball load when the \(n\)th ball - resistance - reducing module 1 leaves the fairlead 2, \(F_{a1}\) be the tension at the head end of the submarine cable 3 when the first ball - resistance - reducing module 1 leaves the fairlead 2, \(F_{a2}\) be the tension at the head end of the submarine cable 3 when the second ball - resistance - reducing module 1 leaves the fairlead 2, and \(F_{a}\) n be the tension at the head end of the submarine cable 3 when the \(n\)th ball - resistance - reducing module 1 leaves the fairlead 2, \(F_{b1}\) be the tension at the tail end of the submarine cable 3 when the first ball - resistance - reducing module 1 leaves the fairlead 2, \(F_{b2}\) be the tension at the tail end of the submarine cable 3 when the second ball - resistance - reducing module 1 leaves the fairlead 2, and \(F_{b}\) n be the tension at the tail end of the submarine cable 3 when the \(n\)th ball - resistance - reducing module 1 leaves the fairlead 2, \(f_{a}\) be the in - pipe friction coefficient, and \(f_{b}\) be the out - of - pipe friction coefficient.

[0076] Specifically, referring to Figure 4 , in a possible embodiment, there are nine ball - resistance - reducing modules 1 in total. The first tension sensor 6 is used to measure the tension at the head end of the submarine cable 3, and the second tension sensor 7 is used to measure the tension at the tail end of the submarine cable 3; the 11s, 20s, 33s, 49s, 64s, 80s, 90s, 107s, 113s are the times when the first, second, …, ninth ball - resistance - reducing modules 1 leave the fairlead 2 in sequence. Based on the data as Figure 4 shown, a friction - coefficient model including the in - pipe friction coefficient and the out - of - pipe friction coefficient is established as follows:

[0077]

[0078] Among them, n is the total number of several of the ball friction reduction modules 1, 20290 is the in-pipe ball load when the first ball friction reduction module 1 leaves the cable guide pipe 2, 18220 is the in-pipe ball load when the second ball friction reduction module 1 leaves the cable guide pipe 2, 15580 is the in-pipe ball load when the third ball friction reduction module 1 leaves the cable guide pipe 2, 12970 is the in-pipe ball load when the fourth ball friction reduction module 1 leaves the cable guide pipe 2, 11460 is the in-pipe ball load when the fifth ball friction reduction module 1 leaves the cable guide pipe 2, 8100 is the in-pipe ball load when the sixth ball friction reduction module 1 leaves the cable guide pipe 2, 5960 is the in-pipe ball load when the seventh ball friction reduction module 1 leaves the cable guide pipe 2, 3320 is the in-pipe ball load when the eighth ball friction reduction module 1 leaves the cable guide pipe 2, and 0 is the in-pipe ball load when the ninth ball friction reduction module 1 leaves the cable guide pipe 2.

[0079] 1440 is the out-of-pipe ball load when the first ball friction reduction module 1 leaves the cable guide pipe 2, 3510 is the out-of-pipe ball load when the second ball friction reduction module 1 leaves the cable guide pipe 2, 6150 is the out-of-pipe ball load when the third ball friction reduction module 1 leaves the cable guide pipe 2, 8790 is the out-of-pipe ball load when the fourth ball friction reduction module 1 leaves the cable guide pipe 2, 11460 is the out-of-pipe ball load when the fifth ball friction reduction module 1 leaves the cable guide pipe 2, 13630 is the out-of-pipe ball load when the sixth ball friction reduction module 1 leaves the cable guide pipe 2, 15770 is the out-of-pipe ball load when the seventh ball friction reduction module 1 leaves the cable guide pipe 2, 18410 is the out-of-pipe ball load when the eighth ball friction reduction module 1 leaves the cable guide pipe 2, and 27130 is the out-of-pipe ball load when the ninth ball friction reduction module 1 leaves the cable guide pipe 2.

[0080] 8750 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the first ball friction reduction module 1 leaves the fairlead 2. 4420 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the second ball friction reduction module 1 leaves the fairlead 2. 6440 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the third ball friction reduction module 1 leaves the fairlead 2. 7240 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the fourth ball friction reduction module 1 leaves the fairlead 2. 5900 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the fifth ball friction reduction module 1 leaves the fairlead 2. 6780 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the sixth ball friction reduction module 1 leaves the fairlead 2. 5880 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the seventh ball friction reduction module 1 leaves the fairlead 2. 6980 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the eighth ball friction reduction module 1 leaves the fairlead 2. 6880 is the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 when the ninth ball friction reduction module 1 leaves the fairlead 2.

[0081] It should be noted that the unit of the acting force in the above system of equations for the friction coefficient is N. The above friction coefficient model is solved using the least squares method, and the friction coefficient inside the pipe fa is obtained as 0.318, and the friction coefficient outside the pipe fb (i.e., the friction coefficient between the ball friction reduction module 1 and the test ground) is 0.269.

[0082] In this embodiment, since the process of towing the submarine cable 3 to move can be approximately equivalent to a uniform linear motion process, it can be analyzed that the total value of the traction force received by the submarine cable 3 is equal to the total value of the resistance force received by the submarine cable 3, that is, the difference between the tension at the head end of the submarine cable 3 and the tension at the tail end of the submarine cable 3 is equal to the sum of the external pipe friction resistance and the internal pipe friction resistance of the submarine cable 3. Among them, the external pipe friction resistance received by the submarine cable 3 is equal to the external pipe ball load multiplied by the external pipe friction coefficient; the internal pipe friction resistance received by the submarine cable 3 is equal to the internal pipe ball load multiplied by the internal pipe friction coefficient.

[0083] It should also be noted that for the convenience of testing, the fairlead 2 in the above embodiment is arranged on the ground of the test site. Therefore, when the submarine cable 3 is towed out of the fairlead 2, the ball friction reduction module 1 on the submarine cable 3 will contact the test site, thereby generating an external pipe friction resistance to hinder the movement of the submarine cable 3.

[0084] Preferably, the method for traction test of the submarine cable 3 further includes: setting a plurality of groups of test conditions, traction-testing the submarine cable 3 under each group of the test conditions, and obtaining the corresponding friction coefficient inside the pipe under each group of the test conditions; solving the mean value based on the friction coefficient inside the pipe corresponding to each group of the test conditions to obtain an average friction coefficient, and taking the average friction coefficient as the test result.

[0085] In this embodiment, by repeatedly conducting the traction test of the submarine cable 3 and solving the mean value of the friction coefficients obtained from the results of multiple traction tests, the random error in a single test is reduced, the influence of measurement outliers is effectively reduced, thereby improving the accuracy and reliability of the obtained test results.

[0086] See Figure 5 , an embodiment of the present invention provides a traction test system for a submarine cable 3, which is applicable to the method for traction test of the submarine cable 3 according to any one of the first aspects of the present invention and is used for the traction test of the submarine cable 3. The submarine cable 3 is sleeved with a plurality of ball friction reduction modules 1 and placed inside a cable guide pipe 2. The traction test system for the submarine cable 3 includes a head-end traction device 9, a tail-end traction device 10, a model construction module, and a solution module, wherein:

[0087] The head-end traction device 9 is used to traction the submarine cable 3, and further obtain the head-end tension of the submarine cable 3 when each ball friction reduction module 1 leaves the cable guide pipe 2;

[0088] The tail-end traction device 10 is used to assist the head-end traction device 9 in traction the submarine cable 3, and further obtain the tail-end tension of the submarine cable 3 when each ball friction reduction module 1 leaves the cable guide pipe 2;

[0089] The model construction module is used to obtain the external-ball load and the internal-ball load when each ball friction reduction module 1 leaves the cable guide pipe 2, and thus construct a friction coefficient model based on the external-ball load, the internal-ball load, the head-end tension of the submarine cable 3, and the tail-end tension of the submarine cable 3 corresponding to each ball friction reduction module 1 leaving the cable guide pipe 2;

[0090] The solution module is used to obtain the friction coefficient inside the pipe according to the friction coefficient model, and take the friction coefficient inside the pipe as the test result.

[0091] Specifically, a loading connector 8 is provided at the end of the submarine cable 3, and the submarine cable 3 is connected to the end traction device 10 through the loading connector 8; the head-end traction device 9 further includes a first tension sensor 6, and the first tension sensor 6 is arranged on the connecting steel wire rope between the head-end traction device 9 and the submarine cable 3; the end traction device 10 further includes a second tension sensor 7, and the second tension sensor 7 is arranged on the connecting steel wire rope between the end traction device 10 and the loading connector 8; the model construction module is connected to the first tension sensor 6 and the second tension sensor 7; the model construction module uses the first tension sensor 6 to measure the head-end tension of the submarine cable 3 and uses the second tension sensor 7 to measure the end tension of the submarine cable 3.

[0092] The above-mentioned submarine cable 3 traction test system realizes the submarine cable 3 traction test method described in the first aspect of the present invention. For the submarine cable 3 sleeved with a plurality of ball drag reduction modules 1 to reduce the traction friction resistance, a cable guide pipe 2 placed on the ground is used for traction test, and a friction coefficient equation corresponding to this moment is constructed based on the external pipe ball load, internal pipe ball load, head-end tension of the submarine cable 3, and end tension of the submarine cable 3 corresponding to each ball drag reduction module 1 when it leaves the cable guide pipe 2. Then, a friction coefficient model is constructed according to the friction coefficient equations corresponding to each ball drag reduction module 1 when it leaves the cable guide pipe 2. Finally, the least squares method is used to solve the friction coefficient model to obtain the internal pipe friction coefficient as the traction test result, providing a standardized measurement method for the equivalent friction coefficient between the submarine cable 3 and the cable guide pipe 2 after installing the drag reduction module. In addition, the friction coefficient model solves the internal pipe friction coefficient by comprehensively considering the load conditions of each ball drag reduction module 1 when it leaves the cable guide pipe 2. Compared with obtaining single data and using a single equation to solve, it can effectively reduce the influence of measurement outliers, make the calculation result of the internal pipe friction coefficient closer to the optimal estimate of the true physical parameters, thereby reducing random errors and improving the accuracy of the internal pipe friction coefficient test result.

[0093] In a possible embodiment, the head-end traction device 9 and the end traction device 10 are winches.

[0094] In a possible embodiment, the test site is paved with steel plates, and the cable guide pipe 2 is arranged on the steel plates; the external pipe ball load is the sum of the vertical loads borne by all the ball drag reduction modules 1 rolling on the steel plates after the ball drag reduction module 1 leaves the cable guide pipe 2; the internal pipe ball load is the sum of the vertical loads borne by all the ball drag reduction modules 1 rolling in the cable guide pipe 2 before the ball drag reduction module 1 leaves the cable guide pipe 2.

[0095] In a possible embodiment, an auxiliary supporting device is further provided, and a rubber layer is further laid between the cable guide pipe 2 and the end traction device 10. The auxiliary supporting device is a movable trolley with a supporting and protecting structure. The movable trolley is equipped with a second tension sensor 7 and travels on the rubber layer, so as to prevent the second tension sensor 7 from being damaged due to contact friction with the test ground during the traction test.

[0096] It should be noted that, in order to improve the accuracy of the test results, in some possible implementation manners, it is necessary to repeatedly perform the cable 3 traction test on the same section of the test submarine cable 3. However, during the process of the end of the test submarine cable 3 being pulled by the traction force multiple times, it is easy to exceed its load fatigue limit and break.

[0097] See Figure 6 , to solve the above technical problems, in a preferred implementation manner, it further includes a traction protection module 4 and a plurality of prestressed steel cables 5, wherein: the traction protection module 4 is sleeved on the head end of the cable 3 and is connected to the head end traction device 9 and the galvanized copper wire of the cable 3; each prestressed steel cable 5 passes through a plurality of the ball friction reduction modules 1 and is connected to the traction protection module 4.

[0098] In this embodiment, the traction protection module 4 is connected to the galvanized copper wire of the cable 3. The galvanized copper wire of the cable 3 serves as a stress-bearing member to share and bear the traction load at the end of the cable 3, reducing the stress load at the end of the cable 3. At the same time, the prestressed steel cable 5 is used as an auxiliary stress-bearing member. While sharing the traction load at the end of the cable 3, the prestressed steel cable 5 distributes the traction load at the end of the cable 3 to each ball friction reduction module 1 distributed along the length direction of the cable 3, so as to prevent the end of the cable 3 from exceeding its load fatigue limit and breaking during multiple traction tests, thereby enhancing the protection effect of the traction test system on the cable 3.

[0099] Furthermore, using this cable 3 traction test system can perform multiple repeated tests on the cable 3 without damaging the cable 3, improving the test efficiency of the cable 3 traction test, and avoiding errors in the test results caused by replacing the cable 3, thereby enhancing the accuracy of the cable 3 traction test.

[0100] See Figure 6 , preferably, the traction protection module 4 includes a pulling sub-module 17, an equalizing load sub-module 16 and a circular sleeve 19; the pulling sub-module 17 and the circular sleeve 19 are respectively connected to the equalizing load sub-module 16, and the equalizing load sub-module 16 is provided with a plurality of uniformly distributed through holes 18, wherein:

[0101] The circular sleeve 19 is sleeved on the head end of the cable 3;

[0102] After the galvanized copper wires of the submarine cable 3 are grouped and stranded into several groups of galvanized wire ropes, each group of the galvanized wire ropes passes through the corresponding perforation 18 and is fixedly connected to the load-sharing sub-module 16, so that several groups of the galvanized wire ropes are fixedly connected to the load-sharing sub-module 16;

[0103] The pulling sub-module 17 is connected to the head-end traction device 9 and the prestressed steel cable 5.

[0104] In this embodiment, each group of galvanized copper wires is stranded and tied into a group of galvanized wire ropes. The galvanized wire ropes are tougher and more resistant to breakage than single galvanized copper wires, improving the structural reliability of the traction test system for the submarine cable 3. In addition, the perforations 18 in the load-sharing sub-module 16 are evenly distributed in a circle, enabling the galvanized wire ropes to bear force cooperatively and evenly share the traction load at the end of the submarine cable 3, improving the effect of the galvanized copper wires sharing the component force of the traction force at the end of the submarine cable 3. The round sleeve 19 is tightly sleeved on the end of the submarine cable 3, enabling the galvanized copper wires to be evenly stressed and bear force cooperatively.

[0105] See Figure 6 Preferably, each group of the galvanized wire ropes is provided with a strain gauge 20, and the strain gauge 20 is used to detect the force condition of the corresponding galvanized wire rope.

[0106] In this embodiment, the force condition of the galvanized copper wires in the submarine cable 3 is detected by the strain gauge 20, so as to judge whether the galvanized copper wires of the submarine cable 3 are evenly stressed and cooperate with the prestressed steel cable 5 to bear force, enabling the tester to adjust the test system in time according to the data of the strain gauge 20 and improving the reliability of the test system and the accuracy of the test results.

[0107] See Figures 7 to 9 Preferably, the traction protection module 4 includes a sleeve part 11, a traction part 12, a fastening part 13 and a transition part 14; the sleeve part 11 is connected to the transition part 14, and the transition part 14 is connected to the traction part 12, wherein:

[0108] The sleeve part 11 is sleeved on the head end of the submarine cable 3, and it is used to connect the prestressed steel cable 5;

[0109] The transition part 14 includes a strip-shaped hole 15. After the galvanized copper wires of the submarine cable 3 pass through the strip-shaped hole 15, they are clamped on the outer side surface of the sleeve part 11 through the cooperation of the sleeve part 11 and the fastening part 13;

[0110] The traction part 12 is connected to the head-end traction device 9.

[0111] Specifically, the width of the strip-shaped hole 15 is slightly larger than the diameter of the galvanized copper wire.

[0112] In this embodiment, the fastening part 13 is installed on the outer side surface of the sleeve part 11, so as to cooperate with the sleeve part 11 to clamp the part of the galvanized copper wire that is closely attached to the outer side surface of the sleeve part 11, thereby ensuring the firmness of the connection between the traction part 12 and the galvanized copper wire. Among them, the galvanized copper wire passes through the strip-shaped hole 15 and then is closely attached to the outer side surface of the sleeve part 11. In addition, the galvanized copper wires passing through the same strip-shaped hole 15 in the transition part 14 are closely and neatly arranged, which can evenly share the traction load; the width of the strip-shaped hole 15 is slightly larger than the diameter of the galvanized copper wire, which can limit the galvanized copper wire passing through the strip-shaped hole 15 to prevent the galvanized copper wire from being stacked or disordered.

[0113] A submarine cable 3 traction test method and system provided by the present invention has at least the following advantages compared with the prior art:

[0114] 1. The traction protection module 4 is connected to the galvanized copper wire of the submarine cable 3. The galvanized copper wire of the submarine cable 3 serves as a stress-bearing member to share the traction load at the end of the submarine cable 3, reducing the stress load at the end of the submarine cable 3. At the same time, the prestressed steel cable 5 is used as an auxiliary stress-bearing member. While sharing the traction load at the end of the submarine cable 3, the prestressed steel cable 5 disperses the traction load at the end of the submarine cable 3 to each ball friction reduction module 1 distributed along the length direction of the submarine cable 3, thereby preventing the end of the submarine cable 3 from breaking beyond its load fatigue limit during multiple traction tests, so as to enhance the protection effect of the traction test system on the submarine cable 3. Further, using this submarine cable 3 traction test system can perform multiple repeated tests on the submarine cable 3 without causing damage to the submarine cable 3, improving the test efficiency of the submarine cable 3 traction test, and avoiding errors in the test results caused by replacing the submarine cable 3, improving the accuracy of the submarine cable 3 traction test.

[0115] 2. For a submarine cable 3 sleeved with a number of ball friction reduction modules 1 to reduce the traction friction resistance, a guiding cable pipe 2 placed on the ground is used for traction test, and a corresponding friction coefficient equation at this moment is constructed based on the external ball load, internal ball load, the tension at the head end of the submarine cable 3, and the tension at the tail end of the submarine cable 3 corresponding to each ball friction reduction module 1 when it leaves the guiding cable pipe 2. Then, a friction coefficient model is constructed according to the corresponding friction coefficient equations of each ball friction reduction module 1 when it leaves the guiding cable pipe 2. Finally, the least squares method is used to solve the friction coefficient model to obtain the in-pipe friction coefficient as the traction test result, providing a standardized measurement method for the equivalent friction coefficient between the submarine cable 3 and the guiding cable pipe 2 after installing the friction reduction module. In addition, the friction coefficient model comprehensively considers the load conditions of each ball friction reduction module 1 when it leaves the guiding cable pipe 2 to solve the in-pipe friction coefficient. Compared with obtaining single data and using a single equation to solve, it can effectively reduce the influence of measurement outliers, make the calculation result of the in-pipe friction coefficient closer to the optimal estimate of the true physical parameters, thereby reducing random errors and improving the accuracy of the in-pipe friction coefficient test result.

[0116] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0117] As used herein, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments. For the sake of brevity of description, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0118] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several improvements and substitutions can still be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A method for testing the traction of a submarine cable, characterized in that, Applied to the traction test of submarine cables, several ball bearing drag reduction modules are sleeved on the submarine cable and placed in a cable guide pipe. The submarine cable traction test method includes: Traction is applied to the submarine cable, and when each ball bearing drag reduction module leaves the cable guide pipe, the external pipe ball load, the internal pipe ball load, the tension at the head end of the cable, and the tension at the tail end of the cable are obtained; Based on the external pipe ball load, the internal pipe ball load, the tension at the head end of the cable, and the tension at the tail end of the cable corresponding to when each ball bearing drag reduction module leaves the cable guide pipe, a friction coefficient model is constructed; Based on the friction coefficient model, the internal pipe friction coefficient is obtained and used as the test result.

2. The submarine cable traction test method according to claim 1, characterized in that, Before the step of applying traction to the submarine cable and obtaining the external pipe ball load, the internal pipe ball load, the tension at the head end of the cable, and the tension at the tail end of the cable when each ball bearing drag reduction module leaves the cable guide pipe, it includes: For any ball bearing drag reduction module, the initial vertical load of the ball bearing drag reduction module is obtained, and thus the initial vertical load corresponding to each ball bearing drag reduction module is obtained; The step of applying traction to the submarine cable and obtaining the external pipe ball load, the internal pipe ball load, the tension at the head end of the cable, and the tension at the tail end of the cable when each ball bearing drag reduction module leaves the cable guide pipe includes: Based on the initial vertical load corresponding to each ball bearing drag reduction module, the external pipe ball load and the internal pipe ball load are obtained.

3. The submarine cable traction test method according to claim 2, wherein The step of obtaining the initial vertical load of any ball bearing drag reduction module and thus obtaining the initial vertical load corresponding to each ball bearing drag reduction module includes: For any ball bearing drag reduction module, the weight of the submarine cable borne by the ball bearing drag reduction module and the weight of the ball bearing drag reduction module are obtained, and the weight of the submarine cable and the weight of the ball bearing drag reduction module are used as the initial vertical load of the ball bearing drag reduction module.

4. The submarine cable traction test method according to claim 1, characterized in that, In the step of constructing the friction coefficient model based on the external pipe ball load, the internal pipe ball load, the tension at the head end of the cable, and the tension at the tail end of the cable corresponding to when each ball bearing drag reduction module leaves the cable guide pipe, the friction coefficient model is specifically: Among them, n is the total number of several of the ball friction reduction modules, Ma1 is the in-pipe ball load when the first ball friction reduction module leaves the fairlead, Ma2 is the in-pipe ball load when the second ball friction reduction module leaves the fairlead, and Ma n is the in-pipe ball load when the nth ball friction reduction module leaves the fairlead, Mb1 is the out-of-pipe ball load when the first ball friction reduction module leaves the fairlead, Mb2 is the out-of-pipe ball load when the second ball friction reduction module leaves the fairlead, and Mb n is the out-of-pipe ball load when the nth ball friction reduction module leaves the fairlead, Fa1 is the cable head tension at the sea cable end when the first ball friction reduction module leaves the fairlead, Fa2 is the cable head tension at the sea cable end when the second ball friction reduction module leaves the fairlead, and Fa n is the cable head tension at the sea cable end when the nth ball friction reduction module leaves the fairlead, Fb1 is the cable end tension at the sea cable end when the first ball friction reduction module leaves the fairlead, Fb2 is the cable end tension at the sea cable end when the second ball friction reduction module leaves the fairlead, and Fb n is the cable end tension at the sea cable end when the nth ball friction reduction module leaves the fairlead, fa is the in-pipe friction coefficient, and fb is the out-of-pipe friction coefficient.

5. A method for testing the traction of a submarine cable according to claim 1, characterized in that, It further includes: Several groups of test conditions are set to apply traction to the submarine cable under each group of test conditions and obtain the corresponding internal pipe friction coefficient under each group of test conditions; Based on the internal pipe friction coefficients corresponding to each group of test conditions, the average friction coefficient is obtained by averaging, and the average friction coefficient is used as the test result.

6. A submarine cable traction test system, characterized in that, Applicable to a submarine cable traction test method as described in any one of claims 1 - 5 for the traction test of submarine cables. Several ball bearing drag reduction modules are sleeved on the submarine cable and placed in a cable guide pipe. The submarine cable traction test system includes a head end traction device, a tail end traction device, a model construction module, and a solution module, where: The head end traction device is used to apply traction to the submarine cable and obtain the tension at the head end of the cable when each ball bearing drag reduction module leaves the cable guide pipe; The tail end traction device is used to assist the head end traction device in applying traction to the submarine cable and obtain the tension at the tail end of the cable when each ball bearing drag reduction module leaves the cable guide pipe; The model construction module is used to obtain the external pipe ball load and the internal pipe ball load when each of the ball drag reduction modules leaves the cable guide pipe, and thus construct a friction coefficient model based on the corresponding external pipe ball load, internal pipe ball load, the tension at the head end of the submarine cable, and the tension at the tail end of the submarine cable when each of the ball drag reduction modules leaves the cable guide pipe; The solution module is used to obtain the internal pipe friction coefficient according to the friction coefficient model and use the internal pipe friction coefficient as the test result.

7. A submarine cable traction test system according to claim 6, characterized in that, It further includes a traction protection module and a number of prestressed steel cables, where: The traction protection module is sleeved on the head end of the submarine cable and is connected to the head end traction device and the galvanized copper wire of the submarine cable; After each prestressed steel cable passes through a number of the ball drag reduction modules, it is connected to the traction protection module.

8. A submarine cable traction test system according to claim 7, characterized in that, The traction protection module includes a pulling sub-module, a load sharing sub-module, and a circular collar; the pulling sub-module and the circular collar are respectively connected to the load sharing sub-module, and the load sharing sub-module is provided with a number of uniformly distributed through holes, where: The circular collar is sleeved on the head end of the submarine cable; The galvanized copper wires of the submarine cable are grouped and stranded into a number of groups of galvanized copper wire ropes, and each group of the galvanized copper wire ropes passes through the corresponding through hole and is bound and connected to the load sharing sub-module, so that a number of groups of the galvanized copper wire ropes are bound and connected to the load sharing sub-module; The pulling sub-module is connected to the head end traction device and the prestressed steel cable.

9. The submarine cable traction test system according to claim 8, wherein Each group of the galvanized copper wire ropes is provided with a strain gauge, and the strain gauge is used to detect the stress condition of the corresponding galvanized copper wire rope.

10. A submarine cable traction test system according to claim 7, characterized in that, The traction protection module includes a sleeve part, a traction part, a fastening part, and a transition part; the sleeve part is connected to the transition part, and the transition part is connected to the traction part, where: The sleeve part is sleeved on the head end of the submarine cable and is used to connect the prestressed steel cable; The transition part includes a strip-shaped hole, and after the galvanized copper wire of the submarine cable passes through the strip-shaped hole, it is clamped on the outer side of the sleeve part through the cooperation of the sleeve part and the fastening part; The traction part is connected to the head end traction device.

Images