Rapid laying method for submarine transmission cable with multi-branch structure

Abstract

The invention discloses a laying method of a submarine cable with a multi-branch structure, belongs to the technical field of ocean engineering, and is particularly suitable for a scene in which multi-node underwater measurement and test equipment need to carry out power transmission and signal transmission on multiple points. The method is characterized in that a corresponding point of an underwater pre-laying position is calibrated at a ship side by using a guide rope, so that an operator can clearly know the laying position of each branch of the submarine cable. Through traction of the guide rope, a simultaneous laying mode is adopted, so that the whole submarine cable falls to a preset laying position of the seabed by utilizing gravity. The submarine cable laying method has the advantages that a traditional method that submarine cables are laid underwater by divers in one-time laying is improved, the underwater working time of the divers is greatly shortened, the underwater working intensity of the divers is greatly reduced, the laying efficiency of the submarine cables of the multi-branch structure is improved, and meanwhile the probability that the submarine cables are damaged in the laying process is reduced.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering technology and relates to a method for laying multi-branch submarine cables, which is particularly suitable for scenarios where multi-node underwater measurement and testing equipment needs to transmit power and signals to multiple points. Background Technology

[0002] With the development of marine resources and underwater technology, especially the large-scale and clustered development of offshore wind power, traditional point-to-point submarine cable systems can no longer meet the demand for efficient and economical connections between multiple underwater devices. Multi-branch submarine cables have emerged to address this need. They connect multiple branch submarine cables through a main cable and a hub, forming a tree-like or star-shaped network, which greatly reduces the total amount of submarine cables used and the amount of laying work.

[0003] Branched submarine cables and their laying technology are the cornerstone of modern marine energy and communication development. Through innovative cable structures and sophisticated marine engineering methods, they have achieved a leap from "point-to-point" to "point-to-multi-faceted," significantly improving the economics and feasibility of projects. The reliable installation of the branch units is crucial to the success of the entire project, typically requiring the coordinated operation of specialized laying vessels, dynamic positioning systems, and underwater robots, representing a concentrated embodiment of cutting-edge technology in the field of marine engineering.

[0004] For laying branch cables for precision equipment with closely spaced underwater nodes, the common method is to deploy the multi-node branch cable to the designated location all at once, with divers or underwater robots laying it node by node underwater. While these methods involve relatively little work for the deployment vessels and personnel, the main challenge lies in the underwater operations of the divers and underwater robots. The underwater workload is particularly heavy, requiring long-distance towing of the cable while carrying it, and there is also the risk of damaging the branch cables. Therefore, for this type of multi-branch cable structure, a stable and safe laying method is urgently needed to reduce the underwater workload for divers and the probability of branch cable damage during the laying process. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a rapid laying method for multi-branch submarine cables, thereby solving the problem of difficult laying of multi-branch submarine cables.

[0006] The technical solution adopted by this invention to solve its technical problem is a method of simultaneously laying multi-branch submarine cables using guide ropes. The main steps are as follows:

[0007] Step 1: Prepare the submarine cable. Attach each branch cable of the submarine cable to the main laying cable, making the branch cables and the main laying cable a whole, which facilitates transportation and storage and is also safer;

[0008] Step 2: Prepare the deployment vessel. Select a vessel with a hull length sufficient to cover the deployment points of each branch cable on the seabed, and with sufficient space beside the hull for personnel to operate. Anchor the deployment vessel above the planned deployment points, ensuring that one side of its hull is directly above each branch cable deployment point.

[0009] Step 3: Laying the guide rope. One end of the guide rope is fixedly connected to the laying point of the branch cable on the seabed, and the other end is connected to a fixed point on the ship's side directly above it. The guide rope should have some redundancy so that it does not bear the tension caused by the floating of the laying vessel at sea. The guide ropes of all branch cables are laid using the same method. In this way, the distance between adjacent fixed points on the ship's side is the same as the spacing between the underwater branch cable laying points, as shown in the schematic diagram. Figure 1 As shown;

[0010] Step 4: Connecting the branch cables to the guide ropes. The underwater anchor point of each guide rope is the underwater deployment point of the branch cable. Each branch point of the branch cable is placed beside the ship's side with its corresponding guide rope, and then the guide rope is "sleeved" in place by a "U" shaped buckle.

[0011] Step 5: Deploy the branch cables. Simultaneously lift the branch cables and lower the entire branch cable into the water. Since the density of the branch cables is greater than that of water, each branch cable will sink to the bottom under the pull of the guide rope after entering the water, reaching the vicinity of the pre-deployment point.

[0012] Step Six: Repeatedly loosen and pull the guide rope. Because the guide rope has redundancy in the water and is not connected straight to the bottom, it is necessary to repeatedly loosen and pull the guide rope to prevent the branch cable from getting stuck during the sinking process, and to ensure that the branch cable can fall more accurately to the deployment point.

[0013] Step 7: Retrieve the guide rope and connect the equipment. Once the branch cable has fallen to the designated position, the guide rope can be retrieved. The branch cable can then be used for connecting the equipment or other operations.

[0014] The effects and benefits of this invention are as follows: By using a guide rope to mark the corresponding points of the underwater pre-deployment position at the ship's side, operators can more clearly identify the deployment location of the branch cables. A highlight of this invention is the simultaneous deployment method using the guide rope, allowing the branch cables to fall to their designated seabed positions by gravity. This operation significantly reduces the underwater working time and intensity for divers, improves the deployment efficiency of multi-branch submarine cables, and also reduces the likelihood of damage during the branch cable deployment process. Attached Figure Description

[0015] Appendix Figure 1 This is a diagram showing the connection of the guide rope;

[0016] Appendix Figure 2 It is a diagram of submarine cable preparation.

[0017] Appendix Figure 3 This is a diagram showing submarine cables placed on the ship's side.

[0018] Appendix Figure 4 This is a diagram of a U-shaped buckle connecting the guide rope. Detailed Implementation

[0019] The specific embodiments of the present invention are described in detail below with reference to the technical solution.

[0020] Step 1: Find an open space and fully unwind, break, and straighten all branch cables of the submarine cable. Then, coil each branch cable in a figure-eight pattern, aligning the branching point with the midpoint of the figure-eight. Coiling in a figure-eight pattern involves coiling the cable along the strokes of the figure-eight in the same position. This creates layers of cable, making it easier to manage, and when unwound, the cable is straight and requires no further breaking. Then, use long ropes to support the multi-branched submarine cable structure and secure the main cable, the submarine cable, and the figure-eight branch cables with thin ropes. The actual operation is as follows... Figure 2 As shown;

[0021] Step 2: After finding a suitable deployment vessel, anchor it at the pre-deployment position, with one side of the vessel's side directly above the underwater deployment point;

[0022] Step 3: Based on the spacing of the underwater branch cable deployment points, locate the anchor points for each guide rope at the same spacing along the ship's side. If none are found, a short section of steel can be welded at the planned location as an anchor point for the guide rope on the ship. Divers must find suitable locations near the underwater deployment points of each branch cable to serve as anchor points for the guide ropes and connect them.

[0023] Step 4: Transport the multi-branch submarine cable to the ship's side and unfurl it along the hull. Each person is responsible for one branch cable (e.g., one "8"), placing it at the point on the ship's side where it connects to the underwater deployment points of each branch cable. Use "U"-shaped clips to connect the cables at the midpoints of each "8," simultaneously securing them to the guide rope, allowing the "U"-shaped clips to slide smoothly along the guide rope with the branch cables. Actual operation is as follows... Figure 3 , Figure 4 As shown

[0024] Step 5: Each person is responsible for one figure-eight branch cable. Lift it around the ship's side, ensuring there are no snags on the entire cable, and lower it into the water while giving the command. Then, each person takes a guide rope and slowly pulls it until the cable reaches the seabed.

[0025] Step Six: After the submarine cable reaches the expected position, the diver can perform other operations, such as retrieving the guide rope, opening the figure-eight branch cable, and connecting equipment.

[0026] The above implementation scheme enables the rapid laying of multi-branch submarine cables, achieving a safe and fast laying effect.

Claims

1. A method for rapid laying of a multi-branch submarine cable, characterized by the following steps: Step 1: Prepare the submarine cable. Attach each branch cable of the submarine cable to the main laying cable, making the branch cables and the main laying cable a whole, which facilitates transportation and storage and is also safer; Step 2: Prepare the deployment vessel. Select a vessel with a hull length sufficient to cover the deployment points of each branch cable on the seabed, and with sufficient space beside the hull for personnel to operate. Anchor the deployment vessel above the planned deployment points, ensuring that one side of its hull is directly above each branch cable deployment point. Step 3: Laying the guide rope. One end of the guide rope is fixedly connected to the laying point of the branch cable on the seabed, and the other end is connected to a fixed point on the ship's side directly above it. The guide rope should have some redundancy so that it does not bear the tension caused by the floating of the laying vessel at sea. The guide ropes of each branch cable are laid using the same method. In this way, the distance between adjacent fixed points on the ship's side is the same as the spacing between the underwater branch cable laying points; Step 4: Connecting the branch cables to the guide ropes. The underwater anchor point of each guide rope is the underwater deployment point of the branch cable. Each branch point of the branch cable is placed beside the ship's side with its corresponding guide rope, and then the guide rope is "sleeved" in place by a "U"-shaped buckle. Step 5: Deploy the branch cables. Simultaneously lift the branch cables and lower the entire branch cable into the water. Since the density of the branch cables is greater than that of water, each branch cable will sink to the bottom under the pull of the guide rope after entering the water, reaching the vicinity of the pre-deployment point. Step Six: Repeatedly loosen and pull the guide rope. Because the guide rope has redundancy in the water and is not connected straight to the bottom, it is necessary to repeatedly loosen and pull the guide rope to prevent the branch cable from getting stuck during the sinking process, and to ensure that the branch cable can fall more accurately to the deployment point. Step 7: Retrieve the guide rope and connect the equipment. Once the branch cable has fallen to the designated position, the guide rope can be retrieved. The branch cable can then be used for connecting the equipment or other operations.

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