A method for repairing submarine cables

Abstract

The present invention discloses a submarine cable repair method, which specifically includes the following operating steps: S1: DP positioning and cleaning of cement gangue protection, S2: fault point cutting and processing, S3: dismantling anchoring device, S4: cutting off protection point and recovering protection device, S5: pulling new submarine cable and installing anchoring device, S6: measuring water depth and calculating submarine cable demand, S7: making joints, S8: lowering submarine cable, S9: restoring cement gangue and covering protection, S10: handover test, etc. The present application adopts a self-propelled workboat with DP positioning function, and divers and joint makers cooperate to carry out repairs and use a transport boat as an auxiliary. In the repair process, only divers and technicians of the joint making process need to cooperate. The operation process is short and has the characteristics of safety, efficiency, strong adaptability and low average maintenance price. The repair efficiency is improved on the basis of reducing the number and level of personnel configuration, which can effectively shorten the fault time of submarine cable and improve the stability of power transmission.

Description

Technical Field

[0001] The invention relates to a submarine cable maintenance method and belongs to the technical field of submarine cable maintenance. Background Art

[0002] In offshore wind power projects, submarine cables serve as the lifeblood of offshore wind farms, ensuring power transmission stability and reliability. With the rapid development of offshore wind power projects, the application of submarine cables is expanding. As the number of submarine cables installed increases, so too does the maintenance workload. Maintenance response speed has become a key factor impacting the reliability of submarine cables. Existing submarine cable maintenance methods generally suffer from inefficient maintenance, low adaptability, and significant impact from the construction environment. Summary of the Invention

[0003] In order to solve the problems in the above background technology, the present invention provides a submarine cable maintenance method.

[0004] The technical solution for achieving the purpose of the present invention is: a submarine cable maintenance method, comprising the following steps:

[0005] S1: Drive the DP positioning vessel to the laying location, clean the submarine cable and cover it with cement strips for protection;

[0006] S2: Cut the cable at the fault point, bundle the submarine cable and salvage the submarine cable end to the cable laying vessel;

[0007] S3: Remove the submarine cable anchoring device and pull the submarine cable to the wind turbine;

[0008] S4: Cut off the submarine cable protection point and recycle the protection device of the submarine cable protection point inside and outside the wind turbine. During the recycling process, a pulling wire is reserved on the wind turbine.

[0009] S5: Connect the pulling wire to the new submarine cable protection device and the submarine cable, pull the submarine cable to the set position of the wind turbine, and install the anchoring device;

[0010] S6: Measure the water depth, make the required length of the submarine cable joint, and cut the submarine cable;

[0011] S7: making joints;

[0012] S8: lowering the submarine cable;

[0013] S9: Perform cement joint restoration and cover protection treatment on submarine cables;

[0014] S10: Perform handover test.

[0015] The submarine cable repair method adopted in this application adopts a self-propelled work boat with DP positioning function, and the repair is carried out by divers and joint makers. A transport boat can be used as an auxiliary in the repair process. The submarine cable is connected by pulling and positioning in the repair process. The repair process only requires the cooperation of divers and technicians in the joint making process. Compared with the method of repairing the submarine cable after salvaging the entire cable ashore, the operation process is short, and it is safe, efficient, adaptable, and has low amortized repair costs. It improves the maintenance efficiency on the basis of reducing the number and configuration level of personnel, can effectively shorten the failure time of the submarine cable, and improve the stability of power transmission.

[0016] The method for cleaning the cement bundling protection covering the submarine cable in step S1 is: a diver dives to the laying location, removes the silt covering the submarine cable in the area until the damaged location of the cable is exposed, and then further cleans the damaged location until the debris covering the cable at the damaged location is removed.

[0017] This step is the basis for subsequent operations. It is conducive to effectively locating the fault location and can effectively avoid secondary damage caused by unclear specific circumstances during operation. Compared with large-scale excavation or the use of powerful equipment, it has less impact on the marine environment.

[0018] The specific method for cutting off the fault point in step S4 is as follows: a diver cuts the submarine cable at the fault point, then ties the cable end to a ship crane, and then uses the crane to salvage the cable to a cable-laying vessel; after the cutting process, the cable at the wind turbine end is waterproofed.

[0019] During the above operation, divers precisely cut the fault point and then a crane safely transfers the cut submarine cable to the cable-laying vessel, ensuring the targetedness and effectiveness of subsequent work, avoiding blind operation and the risk of damage during the submarine cable transfer process. Compared with existing solutions, it has stronger stability and lower subsequent maintenance costs.

[0020] During the process of cutting the submarine cable protection point, the diver dives to the corresponding position of the submarine cable protection device to complete the cutting, and then the personnel inside the wind turbine and the diver respectively connect the cut protection joint to the crane, and use the crane to pull the completed split parts to the designated position and then transfer them; after the diver connects the cut protection joint to the crane, he fixes the pulling wire extending from the wind turbine to the position where the submarine cable extends from the wind turbine, and performs preliminary fixation to prevent it from falling off in preparation for the next traction setting.

[0021] During the above-mentioned operation, the divers and the personnel inside the wind turbine worked together to reduce the risk of single-person operation. At the same time, the use of the crane reduced the safety hazards in the process of moving heavy objects. The initial fixing method used steel wire for pulling, which can effectively prevent falling off and further improve the stability of the operation. The collaborative operation of the divers and the operators inside the wind turbine effectively simplified the process, improved the work efficiency, and made the overall operation process transfer smoother. While effectively shortening the construction time, it can also reduce the waste of working hours caused by waiting or repeated operations.

[0022] In step S5, the method for connecting the new submarine cable protection device and the submarine cable by pulling the steel wire is as follows: when the cable-laying vessel travels close to the wind turbine, a temporary fixing point is set under the cable-laying vessel, and after placing a waterproof underwater pulling device at the temporary fixing point, the pulling steel wire of the underwater pulling device is connected to the new submarine cable, and the underwater pulling device is used to pull the new cable and connect the new cable to the wind turbine.

[0023] This operation step uses an underwater pulling device to set the precise laying path of the new submarine cable, effectively avoiding the position deviation that may occur in traditional laying methods. The waterproof function of the underwater pulling device ensures the normal operation of the equipment in complex marine environments and improves the overall reliability of the maintenance process. Its precise pulling path design can effectively improve the maintainability of the laying path and facilitate the subsequent work.

[0024] The method for measuring the water depth and confirming the required length of the submarine cable joint in step S6 is: using sonar or depth meter to obtain water depth data, calculating the required submarine cable length according to the actual water depth and cable laying path of the submarine cable, and setting the reserved amount to 5-10%.

[0025] During the above-mentioned operation, sonar or depth meter is used for data collection. The overall accuracy of data acquisition is relatively high, which can effectively reduce errors caused by inaccurate estimates, thereby effectively improving the overall reliability of the project. The set error of 5-10% not only takes into account the unstable factors in the construction process, but also avoids the waste caused by excessive reservation of resources. In the marine environment, the reserved length can also be used as a mechanical buffer area, ensuring the electrical performance and mechanical strength of the submarine cable in different environments. It is conducive to reducing failures and improving the stability of the system maintenance in the long-term maintenance of the cable.

[0026] The method for making the joint in step S7 is: introducing the two ends of the submarine cables to be connected into a special joint making platform, stripping, cleaning, insulation treatment, material filling, sealing and mechanical strength measurement are carried out in a dry and clean environment, and then testing its electrical performance.

[0027] The above operation process is carried out in a dry and clean environment, which can effectively prevent moisture and impurities from entering the cable, ensure the quality and long-term stability of the joint, and avoid corrosion and electrical failures caused by external contamination; its good joint production environment can improve the safety of the operation process and reduce the risk of workers accidentally contacting high-voltage cables; the joint production process and the electrical performance testing process are well connected, which effectively simplifies the operation process, reduces the conversion time between different processes, and is conducive to improving overall efficiency.

[0028] The specific method for performing the cement interlocking restoration and covering protection treatment in step S9 is as follows: confirming the fixed position of the submarine cable, cleaning the silt and debris at the fixed position, fixing the cement interlocking at the corresponding position, and then fixing the submarine cable tightly against the cement interlocking, and finally providing a protective layer on the surface of the submarine cable; the protective layer is concrete or other covering materials, and the protective layer is evenly provided on the surface of the submarine cable.

[0029] During the above operation, the installation position of the submarine cable can be effectively confirmed by confirming and cleaning the fixed position, avoiding subsequent stability caused by position deviation; the fit and fixation between the cement row and the submarine cable can provide effective support for the submarine cable, reducing the risk of the submarine cable moving in the ocean current; the concrete covering its surface provides an effective physical barrier for the cable, which can effectively remove the impact of environmental factors on the submarine cable and improve the overall life and maintainability.

[0030] The handover test method in step S10 is: after the installation is completed and the protection measures are restored, preliminary functional testing, abnormal problem correction, system-level testing and test data handover are carried out in sequence.

[0031] The preliminary functional test includes at least an insulation resistance test and a DC withstand voltage test, the system-level test includes at least an AC withstand voltage test, an impact test and a signal transmission test, and the test data includes at least the test date, test equipment, test data and conclusion.

[0032] During the above operation, a phased testing method is used to comprehensively verify the electrical performance and mechanical strength of the submarine cable system. When potential problems or anomalies are found, they can be effectively corrected, avoiding these problems from causing more serious consequences during operation, which is beneficial to improving the overall safety and stability of the system. Complete and detailed data records facilitate the simplification of the maintenance process.

[0033] By adopting the above technical solution, the present invention has the following beneficial effects:

[0034] (1) The submarine cable repair method adopted in the application uses a self-propelled workboat with DP positioning function, and the repair is carried out by divers and joint makers. Transport boats can be used as an auxiliary in the repair process. The submarine cable is connected by pulling positioning in the repair process. The repair process only requires the cooperation of divers and technicians in the joint making process. Compared with the method of repairing the submarine cable after salvaging the entire cable ashore, the operation process is short and it is safe, efficient, adaptable and has low average maintenance costs. It improves the maintenance efficiency on the basis of reducing the number and level of personnel, and can effectively shorten the failure time of the submarine cable and improve the stability of power transmission.

[0035] (2) This application uses a fixed-point diving method to accurately locate the fault location, effectively avoiding secondary damage caused by unclear specific circumstances during operation. Compared with large-scale excavation or the use of powerful equipment, it has less impact on the marine environment.

[0036] (3) The method of abnormal fault point in this application is that the diver accurately cuts the fault point and then the cut submarine cable is safely transferred to the cable laying ship by the crane, which ensures the pertinence and effectiveness of subsequent work, avoids blind operation and the risk of damage during the transfer of the submarine cable. Compared with the existing solution, it has stronger stability and lower subsequent maintenance costs.

[0037] (4) In the process of removing the broken cable, the present application uses the cooperation of divers and personnel inside the wind turbine, which reduces the risk of single-person operation. At the same time, the use of the crane reduces the safety hazards in the process of moving heavy objects. The initial fixing method uses steel wire for pulling, which can effectively prevent it from falling off and further improve the stability of the operation. The collaborative operation of the divers and the operators inside the wind turbine effectively simplifies the process, improves the work efficiency, and makes the overall operation process transfer smoother. While effectively shortening the construction time, it can also reduce the waste of labor time caused by waiting or repeated operations.

[0038] (5) This application uses an underwater pulling device to set the precise laying path of the new submarine cable, effectively avoiding the position deviation that may occur in the traditional laying method. The waterproof function of the underwater pulling device ensures the normal operation of the equipment in a complex marine environment and improves the overall reliability of the maintenance process. Its precise pulling path design can effectively improve the maintainability of the laying path and facilitate the subsequent work.

[0039] (6) This application uses sonar or depth meter for data collection, and the overall accuracy of data acquisition is high, which can effectively reduce the errors caused by inaccurate estimation, thereby effectively improving the overall reliability of the project. The set error of 5 to 10% not only takes into account the unstable factors in the construction process, but also avoids the waste caused by excessive reservation of resources. In the marine environment, the reserved length can also be used as a mechanical buffer area, ensuring the electrical performance and mechanical strength of the submarine cable in different environments, which is conducive to reducing failures and improving the stability of the system maintenance in the long-term maintenance of the cable.

[0040] (7) The connector manufacturing process of the present application is carried out in a dry and clean environment, which can effectively prevent moisture and impurities from entering the cable, ensure the quality and long-term stability of the connector, and avoid corrosion and electrical failures caused by external pollution; its good connector manufacturing environment can improve the safety of the operation process and reduce the risk of workers accidentally contacting high-voltage cables; the connector manufacturing process and the electrical performance testing process are well connected, which effectively simplifies the operation process, reduces the conversion time between different processes, and is conducive to improving overall efficiency.

[0041] (8) This application confirms and cleans the fixed position by diving, and uses the bonding fixation between the cement row and the submarine cable to provide effective support for the submarine cable, reducing the risk of the submarine cable moving in the ocean current; the concrete covering its surface provides an effective physical barrier for the cable, which can effectively remove the impact of environmental factors on the submarine cable and improve the overall life and maintainability.

[0042] (9) This application adopts a phased testing method to comprehensively verify the electrical performance and mechanical strength of the submarine cable system. When potential problems or anomalies are found, they can be effectively corrected, avoiding these problems from causing more serious consequences during operation, which is conducive to improving the overall safety and stability of the system. Complete and detailed data records facilitate the simplification of the maintenance process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings, wherein

[0044] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0045] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0048] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0049] In the description of the embodiments of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0050] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The present invention is further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the scope of protection of the present invention.

[0051] (Example 1)

[0052] Figure 1 This is the operational flow chart of this application.

[0053] The specific operation process includes

[0054] S1: Drive the DP positioning vessel to the laying location, clean the submarine cable and cover it with cement strips for protection;

[0055] S2: Cut the cable at the fault point, bundle the submarine cable and salvage the submarine cable end to the cable laying vessel;

[0056] S3: Remove the submarine cable anchoring device and pull the submarine cable to the wind turbine;

[0057] S4: Cut off the submarine cable protection point and recycle the protection device of the submarine cable protection point inside and outside the wind turbine. During the recycling process, a pulling wire is reserved on the wind turbine.

[0058] S5: Connect the pulling wire to the new submarine cable protection device and the submarine cable, pull the submarine cable to the set position of the wind turbine, and install the anchoring device;

[0059] S6: Measure the water depth, make the required length of the submarine cable joint, and cut the submarine cable;

[0060] S7: making joints;

[0061] S8: lowering the submarine cable;

[0062] S9: Perform cement joint restoration and cover protection treatment on submarine cables;

[0063] S10: Perform handover test.

[0064] Cement gang protection is usually located near the vertical body of the wind turbine. After the diver dives to the bottom of the wind turbine, he uses manual or portable machinery to clean the silt and other impurities on the surface of the gang protection, and then uses a mechanical gang protection to remove the cement blocks on the surface to expose the optical cable.

[0065] After the optical cable is effectively exposed, the divers cut the cable along the side wall of the wind turbine and then bundled its ports. The cable-laying ship operator lowered the traction device for salvaging the submarine cable to the diving point. The divers fixed the bundled submarine cable on the salvage traction device. Then the cable-laying ship staff started the crane, and the cut faulty cable was lifted to the cable-laying ship.

[0066] After the diver completes cutting the faulty cable, he connects the pulling wire to the wind turbine end.

[0067] The detailed process is as follows:

[0068] The method for cleaning the cement bundling protection covering the submarine cable in step S1 is: a diver dives to the laying location, removes the silt covering the submarine cable in the area until the damaged location of the cable is exposed, and then further cleans the damaged location until the debris covering the cable at the damaged location is removed.

[0069] The specific method for cutting off the fault point in step S4 is as follows: a diver cuts the submarine cable at the fault point, then ties the cable end to a ship crane, and then uses the crane to salvage the cable to a cable-laying vessel; after the cutting process, the cable at the wind turbine end is waterproofed.

[0070] During the process of cutting the submarine cable protection point, the diver dives to the corresponding position of the submarine cable protection device to complete the cutting, and then the personnel inside the wind turbine and the diver respectively connect the cut protection joint to the crane, and use the crane to pull the completed split parts to the designated position and then transfer them; after the diver connects the cut protection joint to the crane, he fixes the pulling wire extending from the wind turbine to the position where the submarine cable extends from the wind turbine, and performs preliminary fixation to prevent it from falling off in preparation for the next traction setting.

[0071] After the faulty cable is pulled, the new cable is laid.

[0072] First, place the underwater pulling device at the set position. During the placement process, try to arrange it along the original laying path and pay attention to maintaining its waterproof performance during the placement process.

[0073] In step S5, the method for connecting the new submarine cable protection device and the submarine cable by pulling the steel wire is as follows: when the cable-laying vessel travels close to the wind turbine, a temporary fixing point is set under the cable-laying vessel, and after placing a waterproof underwater pulling device at the temporary fixing point, the pulling steel wire of the underwater pulling device is connected to the new submarine cable, and the underwater pulling device is used to pull the new cable and connect the new cable to the wind turbine.

[0074] During the pulling process, the pulling wire at the wind turbine end is first passed through the cavity of the underwater pulling device to expose it, and then the new submarine cable is lowered by a crane. When the new submarine cable is lowered to the corresponding position of the underwater pulling device, the pulling wire of the wind turbine and the new steel wire are connected. Then the operator at the wind turbine end pulls the new cable through the cavity of the underwater pulling device. After it is completely passed through, the new submarine cable section is cut after leaving enough stress margin, and then it is connected to the original cable.

[0075] The specific margin test process needs to be calculated based on the water depth and ocean current conditions, and the specific data needs to be determined based on the test results.

[0076] The method for measuring the water depth and confirming the required length of the submarine cable joint is: use sonar or depth meter to obtain water depth data, calculate the required submarine cable length according to the actual water depth and cable laying path of the submarine cable, set the reserve amount to 5-10%, and use a 5% margin setting when the ocean current disturbance around the wind turbine is small. When the ocean current disturbance around the wind turbine is large, increase the reserve amount. The test results during the actual construction process show that after the reserve amount exceeds 10%, the stress relief effect gradually decreases and the material cost is still within an acceptable range. Therefore, the limit range of the remaining amount is controlled to be 5% to 10%.

[0077] The method for making the joint in step S7 is: introducing the two ends of the submarine cables to be connected into a special joint making platform, stripping, cleaning, insulation treatment, material filling, sealing and mechanical strength measurement are carried out in a dry and clean environment, and then its electrical performance is tested. The operation and testing process is carried out in an operating chamber with a high-precision filter device with negative pressure balance as much as possible to prevent impurities in the air from contaminating the contact surface and causing changes in electrical performance. During the operation, the layers that can be integrated are made in an integrated manner to prevent stratification at the joint position.

[0078] The specific method for performing the cement interlocking restoration and covering protection treatment in step S9 is as follows: confirming the fixed position of the submarine cable, cleaning the silt and debris at the fixed position, fixing the cement interlocking at the corresponding position, and then fixing the submarine cable tightly against the cement interlocking, and finally providing a protective layer on the surface of the submarine cable; the protective layer is concrete or other covering materials, and the protective layer is evenly provided on the surface of the submarine cable.

[0079] The above-mentioned fixing position should be as close as possible to the original fixing position, so that the operation can be carried out on the base of the original cement joint, which can effectively reduce the amount of silt cleaning and thus reduce the working hours. After the cement joint is fixed, the new submarine cable can be fixed with P·F type fast-hardening silicate cement. The fine aggregate is natural river sand (particle size range is controlled within 0.15-5mm), the coarse aggregate is 5-20mm crushed stone or sand and gravel, calcium aluminate is added as a quick-setting agent, and fly ash and slag powder are used for blending. The concrete is placed in a submerged chamber and a conduit. The corrosion resistance of this cement formula in seawater is better than that of ordinary cement, and it is more conducive to the fixation of submarine cables than ordinary materials. If greater construction strength and corrosion resistance are required, polymer fibers can be used for pre-embedded skeletons and anti-corrosion treatment can be performed on the surface of the concrete pile.

[0080] The handover test method in step S10 is: after the installation is completed and the protection measures are restored, preliminary functional testing, abnormal problem correction, system-level testing and test data handover are carried out in sequence.

[0081] The preliminary functional test at least includes insulation resistance test and DC withstand voltage test; the system-level test at least includes AC withstand voltage test, impact test and signal transmission test; the test data at least includes test date, test equipment, test data and conclusion; during the test, attention should be paid to the integrity and accuracy of the signal and data, and efforts should be made to reduce signal attenuation and distortion.

[0082] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A submarine cable maintenance method, characterized in that The following steps are involved: S1: Drive the DP positioning vessel to the laying location, clean the submarine cable and cover it with cement strips for protection; S2: Cut the cable at the fault point, bundle the submarine cable and salvage the submarine cable end to the cable laying vessel; S3: Remove the submarine cable anchoring device and pull the submarine cable to the wind turbine; S4: Cut off the submarine cable protection point and recycle the protection device of the submarine cable protection point inside and outside the wind turbine. During the recycling process, a pulling wire is reserved on the wind turbine. S5: Connect the pulling wire to the new submarine cable protection device and the submarine cable, pull the submarine cable to the set position of the wind turbine, and install the anchoring device; S6: Measure the water depth, make the required length of the submarine cable joint, and cut the submarine cable; S7: making joints; S8: lowering the submarine cable; S9: Perform cement joint restoration and cover protection treatment on submarine cables; S10: Conduct handover test; During the cutting process of the submarine cable protection point, the diver dives to the corresponding position of the submarine cable protection device and completes the cutting. Then, the personnel inside the wind turbine and the diver connect the cut protection joint to the crane, and use the crane to pull the split parts to the designated location for transfer. After the diver connects the cut protective joint to the crane, he fixes the pulling wire extending from the wind turbine to the position where the wind turbine's submarine cable extends, and performs preliminary fixation to prevent it from falling off in preparation for the next traction setting.

2. A submarine cable repair method according to claim 1, characterized in that: The method for cleaning the cement bundling protection covering the submarine cable in step S1 is: a diver dives to the laying location, removes the silt covering the submarine cable in the area until the damaged location of the cable is exposed, and then further cleans the damaged location until the debris covering the cable at the damaged location is removed.

3. A submarine cable repair method according to claim 1, characterized in that: The specific method for cutting off the fault point in step S4 is as follows: a diver cuts the submarine cable at the fault point, then ties the cable end to a ship crane, and then uses the crane to salvage the cable to a cable-laying vessel; after the cutting process, the cable at the wind turbine end is waterproofed.

4. A submarine cable repair method according to claim 1, characterized in that: In step S5, the method for connecting the new submarine cable protection device and the submarine cable by pulling the steel wire is as follows: when the cable-laying vessel travels close to the wind turbine, a temporary fixing point is set under the cable-laying vessel, and after placing a waterproof underwater pulling device at the temporary fixing point, the pulling steel wire of the underwater pulling device is connected to the new submarine cable, and the underwater pulling device is used to pull the new cable and connect the new cable to the wind turbine.

5. A submarine cable repair method according to claim 1, characterized in that: The method for measuring the water depth and confirming the required length of the submarine cable joint in step S6 is: using sonar or depth meter to obtain water depth data, calculating the required submarine cable length according to the actual water depth of the submarine cable laying and the actual cable laying path, and setting the reserved amount to 5-10%.

6. A submarine cable repair method according to claim 1, characterized in that: The method for making the joint in step S7 is: introducing the two ends of the submarine cables to be connected into a special joint making platform, stripping, cleaning, insulation treatment, material filling, sealing and mechanical strength measurement are carried out in a dry and clean environment, and then testing its electrical performance.

7. A submarine cable repair method according to claim 1, characterized in that: The specific method for performing the cement interlocking restoration and covering protection treatment in step S9 is as follows: confirming the fixed position of the submarine cable, cleaning the silt and debris at the fixed position, fixing the cement interlocking at the corresponding position, and then fixing the submarine cable tightly against the cement interlocking, and finally providing a protective layer on the surface of the submarine cable; the protective layer is concrete or other covering materials, and the protective layer is evenly provided on the surface of the submarine cable.

8. A submarine cable repair method according to claim 1, characterized in that: The handover test method in step S10 is: after the installation is completed and the protection measures are restored, preliminary functional testing, abnormal problem correction, system-level testing and test data handover are carried out in sequence.

9. A submarine cable repair method according to claim 8, characterized in that: The preliminary functional test includes at least an insulation resistance test and a DC withstand voltage test, the system-level test includes at least an AC withstand voltage test, an impact test and a signal transmission test, and the test data includes at least the test date, test equipment, test data and conclusion.

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