Oil-filled submarine cable plugging and repair method

Abstract

The present application relates to a method for sealing and repairing an oil-filled submarine cable. The method comprises the following steps: peeling off the outer sheath of the section of the oil-filled submarine cable where the leakage point is located to expose the armor layer; sleeve the main shell of the oil-filled submarine cable sealing device on the outside of the armor layer of the section of the oil-filled submarine cable where the leakage point is located, so that the sealing component in the main shell separates the space between the main shell and the oil-filled submarine cable into an oil leakage zone and at least one sealing zone on both sides of the oil leakage zone along the axial direction of the main shell, and the leakage point is located in the oil leakage zone; opening the oil drain valve located on the lower side of the oil leakage zone; injecting glue into each of the sealing zones until the glue fills the sealing zone; waiting for the glue to solidify; and closing the oil drain valve. The above-mentioned method for sealing and repairing an oil-filled submarine cable can seal the leakage of the oil-filled submarine cable without damaging the armor layer.

Description

Technical Field

[0001] The present application relates to the technical field of oil-filled submarine cable repair, and in particular to a method for sealing and repairing an oil-filled submarine cable. Background Art

[0002] Oil-filled submarine cables are submarine cables that use insulating oil as a pressurized fluid, allowing the oil to flow freely within the cable. Damage to an oil-filled cable can cause leakage, contaminating the seawater and impacting the stable operation of the power grid.

[0003] Currently, there are several methods for repairing oil-filled submarine cables, including splicing repair, water-blocking repair, and plugging repair. Among them, plugging repair is to form a physical blockage on the outside of the damaged point without repairing the main body. Plugging repair has the technical advantages of being simple, fast, and low-cost.

[0004] Currently, the plugging and repair methods for oil-filled submarine cables mostly refer to the plugging and repair methods for submarine oil and gas pipelines. However, the traditional plugging and repair methods for submarine oil and gas pipelines are not ideal for the plugging and repair of oil-filled submarine cables. Summary of the Invention

[0005] Based on this, it is necessary to provide a method for sealing and repairing oil-filled submarine cables in order to improve the effect of sealing and repairing oil-filled submarine cables.

[0006] The present application provides a method for sealing and repairing an oil-filled submarine cable, comprising the following steps:

[0007] The outer sheath of the oil-filled submarine cable at the leaking point is peeled off to expose the armor layer;

[0008] The main housing of the oil-filled submarine cable plugging device is sleeved over the armor layer of the oil-filled submarine cable at the leakage point, so that the sealing assembly in the main housing separates the space between the main housing and the oil-filled submarine cable into an oil leakage zone and at least one sealing zone located on both sides of the oil leakage zone along the axial direction of the main housing, and the leakage point is located within the oil leakage zone;

[0009] Opening the oil drain valve located at the lower side of the oil drain area;

[0010] injecting glue into each of the sealing areas until the glue fills the sealing area;

[0011] Waiting for the glue to cure;

[0012] Close the oil drain valve.

[0013] The technical solution is further described below:

[0014] In one embodiment, the step of injecting glue into each of the sealing areas until the glue fills the sealing area includes:

[0015] Connecting the glue injection valve located on the lower side of the sealing area to the glue injection system;

[0016] Open the glue injection valve and the glue discharge valve located on the upper side of the sealing area;

[0017] The glue injection system injects glue into the sealing area at a first preset pressure through the glue injection valve;

[0018] When the glue discharge valve continues to discharge the glue for a first period of time, closing the glue discharge valve;

[0019] After the glue injection system maintains the pressure of the sealing area at a second preset pressure for a second period of time, the glue injection valve is closed.

[0020] In one embodiment, the glue includes a high-penetration agent and a low-penetration agent, and the glue injection system injects glue into the sealing area through the glue injection valve at the first preset pressure; when the glue discharge valve continuously flows out the glue for a first time period, the glue discharge valve is closed; after the glue injection system continuously maintains the pressure of the sealing area at the second preset pressure for a second time period, the glue injection valve is closed. The steps include:

[0021] The glue injection system first injects the high-penetration agent into the sealing area at the first preset pressure;

[0022] When the high permeability agent continues to flow out of the glue discharge valve for the first time period, closing the glue discharge valve;

[0023] The glue injection system maintains the pressure of the sealing area at the second preset pressure for the second time period, and then opens the glue discharge valve;

[0024] The glue injection system then injects the low-permeability agent into the sealing area at the first preset pressure;

[0025] When the low-permeability agent continues to flow out of the debonding valve for the first period of time, closing the debonding valve;

[0026] The glue injection system maintains the pressure of the sealing area at the second preset pressure for the second period of time, and then closes the glue injection valve.

[0027] In one embodiment, the first preset pressure ranges from 0.2 MPa to 0.4 MPa; and / or the second preset pressure ranges from 0.5 MPa to 1 MPa.

[0028] In one embodiment, the first time period is 10s-15s; and / or the second time period is 1min-3min.

[0029] In one embodiment, the high permeability agent is fluorosilicone rubber, organic silica gel or polyurethane glue; and / or the low permeability agent is fluorosilicone rubber or silicone rubber.

[0030] In one embodiment, the step of waiting for the glue to solidify comprises:

[0031] The time for waiting for the glue to cure is greater than or equal to 4 hours.

[0032] In one embodiment, the step of closing the oil drain valve further includes the following steps:

[0033] Check the leakage of oil-filled submarine cables;

[0034] If leakage still occurs, add connecting shells at both ends of the main shell so that the connecting shells are sheathed outside the armor layer of the oil-filled submarine cable, and the space between the connecting shells and the oil-filled submarine cable forms a sealed area;

[0035] Injecting glue into the sealing area of the connection housing until the glue fills the sealing area;

[0036] Wait for the glue in the connection housing to solidify.

[0037] In one embodiment, after the step of waiting for the glue in the connection housing to solidify, the method further includes the following steps:

[0038] Check the oil-filled submarine cable for leakage again;

[0039] If leakage still occurs, install another connecting shell at the end of the connecting shell away from the main shell;

[0040] Injecting glue into the sealing area of the added connection housing until the glue fills the sealing area;

[0041] Wait for the glue in the installed connection housing to solidify.

[0042] In one embodiment, before the step of injecting glue into each of the sealing areas until the glue fills the sealing area, the oil-filled submarine cable plugging and repairing method further comprises:

[0043] Connecting the glue injection valve located on the lower side of the sealing area to the cleaning system;

[0044] Open the glue injection valve and the glue discharge valve located on the upper side of the sealing area;

[0045] The cleaning system introduces dry air into the sealing area through the glue injection valve to clean the insulating oil and seawater in the sealing area;

[0046] Close the glue discharge valve and the glue injection valve in sequence, and disconnect the cleaning system from the glue injection valve.

[0047] The above-mentioned method for sealing and repairing an oil-filled submarine cable is centered. The outer sheath of the section of the oil-filled submarine cable where the leakage point is located is first peeled off to expose the armor layer, and then a main shell is arranged outside the armor layer, so that the sealing component in the main shell separates the space between the main shell and the oil-filled submarine cable into an oil leakage area and at least one sealing area located on both sides of the oil leakage area. At the same time, the leakage point is located in the oil leakage area, so that the leaked insulating oil can be discharged from the oil leakage area through the oil drain valve, greatly reducing the possibility of insulating oil leaking into the sealing area, thereby preventing the glue in the sealing area from being washed away by the oil, ensuring the stability of the subsequent glue injection process into the sealing area, so that glue injection can be carried out simultaneously during the oil discharge process, thereby improving the efficiency of sealing and repair. At the same time, by applying glue to the sealing area with a certain pressure, the glue can penetrate into the outside of the PE layer along the copper strip gaps in the armor layer and the gaps between the armor layer and the PE layer under pressure to fill the copper strip gaps in the armor layer and the gaps between the armor layer and the PE layer, thereby avoiding the possibility of axial leakage of insulating oil along the copper strip gaps in the armor layer and the gaps between the armor layer and the PE layer, thereby achieving leakage sealing of the oil-filled submarine cable outside the PE layer without damaging the armor layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings that constitute a part of this application are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] In addition, the drawings are not drawn to a 1:1 scale, and the relative sizes of the various elements are drawn only for illustrative purposes and are not necessarily drawn to true scale.

[0051] Figure 1 Schematic diagram of the structure of an oil-filled submarine cable according to one embodiment.

[0052] Figure 2 The figure is a schematic structural diagram of an oil-filled submarine cable plugging and repairing device according to one embodiment.

[0053] Figure 3This is a cross-sectional view of an oil-filled submarine cable plugging and repairing device according to one embodiment.

[0054] Figure 4 The figure is a flow chart of a method for sealing and repairing an oil-filled submarine cable according to one embodiment.

[0055] Description of reference numerals:

[0056] 10. Oil-filled submarine cable; 11. Oil channel; 12. Conductor layer; 13. Insulation layer; 14. Lead sheath; 15. First non-woven fabric layer; 16. PE layer; 17. Second non-woven fabric layer; 18. Armor layer; 21. Main shell; 211. First half shell; 212. Second half shell; 213. Oil drain area; 214. Sealing area; 22. Sealing assembly; 221. Sealing strip; 222. Ring-shaped sealing gasket; 23. Oil drain valve; 251. Glue injection valve; 252. Glue discharge valve; 30. Connection shell. DETAILED DESCRIPTION

[0057] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0058] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0059] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0060] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0061] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0062] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0063] As mentioned above, the traditional plugging and repairing method for submarine oil and gas pipelines is not ideal for plugging and repairing the oil-filled submarine cable 10. After extensive research, the inventors found that the reason is that the structure of the oil-filled submarine cable 10 is very different from that of the submarine oil and gas pipeline. Figure 1 The through-groove oil-filled submarine cable 10 includes an oil channel 11, a conductor layer 12, an insulating layer 13, a lead sheath 14, a first non-woven fabric layer 15, a PE layer 16, a second non-woven fabric layer 17, an armor layer 18, and an outer sheath (not shown), which are arranged in sequence from the inside out. The gaps between the armor layer 18, the PE layer 16, and the outer sheath are relatively large, and the armor layer 18 is a cylindrical structure composed of multiple copper bars tightly arranged along the circumference, with axial gaps between the copper bars. Therefore, if the oil-filled submarine cable 10 is damaged and the insulating oil inside the oil channel 11 leaks to the outside of the oil-filled submarine cable 10, the insulating oil can leak axially between the armor layer 18, the PE layer 16, and the outer sheath, as well as between the gaps between the copper bars in the armor layer 18.

[0064] Current sealing and repair methods are unable to seal the gaps between the armor layer 18, PE layer 16, and outer sheath, and are unable to resolve the axial leakage problem of the oil-filled submarine cable 10. To achieve sealing, the only way is to destroy the cable armor layer 18 and seal the gaps from the surface of the cable PE layer 16. Damage to the cable armor layer 18 will cause the oil-filled submarine cable 10 to lose its ability to withstand tensile loads. Considering the actual operating conditions of the oil-filled submarine cable 10, axial loads on the oil-filled submarine cable 10 are inevitable. Therefore, it is urgent to develop an effective method for sealing insulating oil leaks in the oil-filled submarine cable 10.

[0065] Based on this, an embodiment of the present application provides a method for sealing and repairing an oil-filled submarine cable 10, which is used to solve the axial leakage problem of the oil-filled submarine cable 10 without damaging the submarine cable armor layer 18. First, in order to better understand the technical solution of the present application, a brief introduction is first given to the oil-filled submarine cable 10 sealing and repairing device used in the method for sealing and repairing an oil-filled submarine cable 10 in one embodiment. Specifically, see Figure 2 as well as Figure 3 In one embodiment, a device for plugging and repairing an oil-filled submarine cable 10 includes a main housing 21 and a sealing assembly 22. The main housing 21 is configured to be mounted on the section of the oil-filled submarine cable 10 where the leak is located. The sealing assembly 22 is disposed within the main housing 21 and is configured to separate the space between the main housing 21 and the oil-filled submarine cable 10 axially into an oil drain area 213 corresponding to the leak point and at least one sealing area 214 located on either side of the oil drain area 213. The oil drain area 213 is connected to an oil drain valve 23. Exemplarily, two drain valves are provided, one of which is located below the oil drain area 213. Each sealing area 214 is provided with a glue injection valve 251 and a glue discharge valve 252. The glue injection valves 251 and the glue discharge valves 252 are radially opposed to each other along the main housing 21, with the glue injection valve 251 located below the glue discharge valve 252.

[0066] Specifically, see Figure 4 A method for repairing an oil-filled submarine cable 10 according to an embodiment of the present invention includes the following steps:

[0067] S110: peeling off the outer sheath of the oil-filled submarine cable 10 at the leak point to expose the armor layer 18;

[0068] S120: The main housing 21 is placed over the armor layer 18 of the oil-filled submarine cable 10 at the leakage point, so that the sealing assembly 22 in the main housing 21 divides the space between the main housing 21 and the oil-filled submarine cable 10 into an oil leakage area 213 and at least one sealing area 214 located on both sides of the oil leakage area 213 along the axial direction of the main housing 21, and the leakage point is located within the oil leakage area 213;

[0069] Specifically, see Figure 1In one embodiment, the main housing 21 comprises a first half-shell 211 and a second half-shell 212. The first half-shell 211 and the second half-shell 212 are connected to form a cylindrical structure. During installation, the first half-shell 211 and the second half-shell 212 are placed opposite each other over the leaking section of the oil-filled submarine cable 10. The first half-shell 211 and the second half-shell 212 are then tightened together to complete the installation of the main housing 21.

[0070] Combine Figure 2 The sealing assembly 22 includes a sealing strip 221 and at least two annular sealing gaskets 222. The sealing strip 221 is disposed in the joint gap between the first and second half shells 211, 212, thereby sealing the gap and preventing leakage of insulating oil or glue. Furthermore, all annular sealing gaskets 222 are spaced apart along the axial direction of the main housing 21, between the main housing 21 and the oil-filled submarine cable 10, and sealably engage with the main housing 21 and the oil-filled submarine cable 10, thereby separating the space between the main housing 21 and the oil-filled submarine cable 10 into an oil drain zone 213 and at least one sealing zone 214 located on either side of the oil drain zone 213.

[0071] S130: Open the oil drain valve 23 located at the lower side of the oil drain area 213;

[0072] Specifically, the oil drain area 213 is connected to two oil drain valves 23, which are arranged radially opposite each other in the main housing 21. When draining the oil, the lower drain valve 23 is opened. Since the density of insulating oil is lower than that of seawater, the seawater can be drained simultaneously with the insulating oil.

[0073] S140: injecting glue into each sealing area 214 until the glue fills the sealing area 214;

[0074] Specifically, glue may be injected into the sealing area 214 through an underwater glue injection system.

[0075] S150: Wait for the glue to solidify;

[0076] S160: Close the oil drain valve 23.

[0077] The above-mentioned method for sealing and repairing the oil-filled submarine cable 10 is centered. The outer sheath of the section where the leak point is located in the oil-filled submarine cable 10 is first peeled off to expose the armor layer 18. Then, a main shell 21 is arranged outside the armor layer 18, so that the sealing assembly 22 in the main shell 21 separates the space between the main shell 21 and the oil-filled submarine cable 10 into an oil leakage area 213 and at least one sealing area 214 located on both sides of the oil leakage area 213. At the same time, the leak point is located in the oil leakage area 213, so that the leaked insulating oil can be discharged from the oil leakage area 213 through the oil discharge valve 23, greatly reducing the possibility of insulating oil leaking into the sealing area 214, thereby preventing the glue in the sealing area 214 from being washed away by the oil, ensuring the stability of the subsequent glue injection process into the sealing area 214, so that glue injection can be carried out simultaneously during the oil discharge process, thereby improving the efficiency of sealing and repair. At the same time, by applying glue to the sealing area 214 with a certain pressure, the glue can penetrate into the outside of the PE layer 16 along the copper strip gaps of the armor layer 18 and the gap between the armor layer 18 and the PE layer 16 under pressure to fill the copper strip gaps of the armor layer 18 and the gap between the armor layer 18 and the PE layer 16, thereby avoiding the possibility of axial leakage of insulating oil along the copper strip gaps of the armor layer 18 and the gap between the armor layer 18 and the PE layer 16, thereby achieving leakage sealing of the part outside the PE layer 16 of the oil-filled submarine cable 10 without damaging the armor layer 18.

[0078] In one embodiment, the steps of step S140 include the following steps:

[0079] S141: Connect the glue injection valve 251 located at the lower side of the sealing area 214 to the glue injection system;

[0080] S142: Open the glue injection valve 251 and the glue discharge valve 252 located on the upper side of the sealing area 214;

[0081] S143: The glue injection system injects glue into the sealing area 214 at a first preset pressure through the glue injection valve 251;

[0082] Specifically, each sealing area 214 is equipped with a glue injection valve 251 and a glue discharge valve 252. The glue injection valves 251 and the glue discharge valves 252 are arranged radially opposite each other in the main housing 21, with the glue injection valves 251 located below the glue discharge valves 252. The glue injection system injects glue into the sealing area 214 from bottom to top through the glue injection valves 251. Since the density of the sealant is greater than that of seawater, the glue is injected from bottom to top, ensuring that the seawater in the sealing area 214 can be discharged through the glue discharge valves.

[0083] For example, in one embodiment, the first preset pressure is in the range of 0.2 MPa to 0.4 MPa. Specifically, if the first preset pressure is too low, the glue cannot be injected into the sealing area 214. If the first preset pressure is too high, it is likely to exceed the safe pressure range of the oil-filled submarine cable 10 and increase costs. By configuring the first preset pressure range to be 0.2 MPa to 0.4 MPa, the glue can be smoothly injected into the sealing area 214 at a lower cost.

[0084] S144: When glue continues to flow out of the glue discharge valve 252 for a first period of time, the glue discharge valve 252 is closed;

[0085] For example, in one embodiment, the first time period is 10s-15s. When the glue drain valve 252 continues to drain glue for 10s-15s, it indicates that the sealing area 214 is filled with glue, ensuring that all seawater is drained, thereby improving the sealing effect of the glue in the sealing area 214.

[0086] S145 : After the glue injection system maintains the pressure of the sealing area 214 at the second preset pressure for a second period of time, the glue injection valve 251 is closed.

[0087] Specifically, after closing the glue discharge valve 252, by continuing to maintain pressure in the sealing area 214 for a period of time, it can be ensured that the glue fully penetrates into the copper strip gaps of the armor layer 18 and the gaps between the armor layer 18 and the PE layer 16, so as to fill the copper strip gaps of the armor layer 18 and the gaps between the armor layer 18 and the PE layer 16, thereby avoiding the possibility of axial leakage of insulating oil along the copper strip gaps of the armor layer 18 and the gaps between the armor layer 18 and the PE layer 16, and at the same time ensuring that the sealing area 214 still has a large internal pressure after the glue solidifies, thereby improving the sealing effect.

[0088] For example, in one embodiment, the range of the second preset pressure is 0.5Mpa-1Mpa. Specifically, after the plugging device of the oil-filled submarine cable 10 is installed, it will have a certain squeezing effect on the oil-filled submarine cable 10. In order to ensure that the external pressure applied to the oil-filled submarine cable 10 is within its safe bearing range, it is necessary to analyze the safe pressure-bearing stability range of the oil-filled submarine cable 10 through theory and experiments. According to simulation analysis, when the external pressure applied to the oil-filled submarine cable 10 is 2MPa, the maximum equivalent stress of the PE layer 16 of the oil-filled submarine cable exceeds the yield limit of the material. At this time, the PE layer 16 of the oil-filled submarine cable 10 may yield. At the same time, according to experimental analysis, when the radially uneven pressure on the oil-filled submarine cable 10 reaches 2.0MPa, the lead sheath 14 of the oil-filled submarine cable 10 will reach the yield limit and deform. Therefore, the inventor of the present application, based on theoretical and experimental analysis, sets the upper limit of the second preset pressure to no more than 1Mpa. At the same time, if the second preset pressure is too low, the glue cannot penetrate into the gaps between the copper bars of the armor layer 18 and the gap between the armor layer 18 and the PE layer 16, and the pressure in the sealing area 214 cannot be guaranteed after the sealant is cured, resulting in a poor sealing effect. Therefore, the inventors of this application combined theoretical and experimental analysis to set the lower limit value of the second preset pressure to greater than 0.5 MPa.

[0089] Furthermore, the second time period, i.e., the time for maintaining pressure in the sealing area 214, is 1-3 minutes. Specifically, if the pressure holding time is too short, good effects will not be achieved, while if the pressure holding time is too long, costs will increase. By configuring the pressure holding time to be 1-3 minutes, costs can be reasonably controlled while ensuring the pressure holding effect.

[0090] Optionally, in one embodiment, the glue used in the method for plugging and repairing the oil-filled submarine cable 10 includes a high-penetration agent and a low-penetration agent. Based on this, in one embodiment, the steps S143 to S145 specifically include the following steps:

[0091] S1431: The glue injection system first injects a high-penetration agent into the sealing area 214 at a first preset pressure;

[0092] S1432: When the high-penetration agent continues to flow out of the glue discharge valve 252 for a first period of time, the glue discharge valve 252 is closed;

[0093] S1433: The glue injection system maintains the pressure of the sealing area 214 at the second preset pressure for a second period of time, and then opens the glue discharge valve 252;

[0094] S1434: The glue injection system injects a low-permeability agent into the sealing area 214 at a first preset pressure;

[0095] S1435: When the glue discharge valve 252 continuously discharges the low-permeability agent for a first period of time, the glue discharge valve 252 is closed;

[0096] S1436: The glue injection system maintains the pressure of the sealing area 214 at the second preset pressure for a second period of time, and then closes the glue injection valve 251.

[0097] Specifically, a high penetrant is a sealant with low viscosity that can penetrate into tiny gaps and achieve the purpose of sealing and leak prevention after solidification. A low penetrant is a material with excellent elasticity and flexibility. A low penetrant is not easy to enter tiny gaps, but has a filling and pressure-maintaining effect, and can balance the pressure of the insulating oil leaking from the oil-filled submarine cable 10. By first injecting a high penetrant into the sealing area 214 and maintaining the pressure for a certain period of time, and then injecting a low penetrant to replace the high penetrant and maintaining the pressure for a certain period of time, the high penetrant injected first can more easily penetrate into the gaps between the copper bars of the armor layer 18 and the gap between the armor layer 18 and the PE layer 16. After the low penetrant is used to replace the high penetrant, the low penetrant can balance the pressure of the insulating oil leaking from the oil-filled submarine cable 10, and at the same time prevent the solidified high penetrant from being squeezed out of the gaps between the layers. This further improves the sealing and repair effect.

[0098] Alternatively, in one embodiment, the high-permeability sealant includes, but is not limited to, fluorosilicone rubber, organic silica gel, or polyurethane glue. For example, in one embodiment, a fluorosilicone gel with a density of approximately 1.27 g / mm3 can be used as the high-permeability sealant. Alternatively, in one embodiment, the low-permeability sealant can be fluorosilicone rubber or silicone rubber.

[0099] Specifically, the steps of waiting for the glue to solidify include:

[0100] S151: Waiting time for the glue to cure is greater than or equal to 4 hours.

[0101] Specifically, a curing time of no less than 4 hours can ensure that the glue is fully cured and ensure the sealing and repair effect after the glue is cured.

[0102] Alternatively, see Figure 2 as well as Figure 3 In one embodiment, the step of closing the oil drain valve 23 further includes the following steps:

[0103] S161: Check the leakage of the oil-filled submarine cable 10;

[0104] Specifically, it is possible to observe with an instrument or with the naked eye whether there is any insulation oil leakage from both ends of the main housing 21 .

[0105] S162: If leakage still occurs, connect the housings 30 to both ends of the main housing 21 so that the connect the housings 30 are sleeved outside the armor layer 18 of the oil-filled submarine cable 10, and the space between the connect the housings 30 and the oil-filled submarine cable 10 forms a sealing area 214.

[0106] Specifically, the structure of the connecting shell 30 is a cylindrical structure, and the connecting shell 30 is sealed with the main shell 21. A sealing assembly 22 is also provided in the connecting shell 30. The sealing assembly 22 seals and encloses the space between the connecting shell 30 and the oil-filled submarine cable 10 to form a sealing area 214.

[0107] S163: Inject glue into the sealing area 214 of the connection housing 30 until the glue fills the sealing area 214;

[0108] Specifically, the sealing area 21433 of each connection housing 30 is also connected to a glue injection valve 251 and a glue discharge valve 252. Furthermore, the steps of injecting glue into the sealing area 214 of the connection housing 30 can refer to the above-mentioned steps S1431 to S1436 of injecting glue into the sealing area 214 of the main housing 21, and are not repeated here.

[0109] S164: Wait for the glue in the connection housing 30 to solidify.

[0110] Specifically, when the sealing effect of the main shell 21 is poor, by adding a connecting shell 30 at the end of the main shell 21, the number of sealing areas 214 in the axial direction of the main shell 21 can be increased, and then by injecting glue into the sealing areas 21433 of the connecting shell 30, the axial sealing effect can be enhanced to avoid axial leakage.

[0111] Furthermore, in one embodiment, the following steps are further included after step S164:

[0112] S165: Check the leakage of the oil-filled submarine cable 10 again:

[0113] S167: If leakage still occurs, install another connection housing at the end of the connection housing 30 away from the main housing 21;

[0114] S168: Inject glue into the sealing area 214 of the attached connection housing 30 until the glue fills the sealing area 214;

[0115] S169: Wait for the glue in the added connection housing 30 to solidify.

[0116] Specifically, the installation method of the additional splicing shell 30 and the method of injecting glue into the additional splicing shell 30 can be referred to the above steps S161 to S164 and will not be described in detail here. Further, steps S165 to S169 are repeated until there is no leakage in the oil-filled submarine cable 10, thereby ensuring that the leakage of the oil-filled submarine cable 10 is completely blocked and repaired.

[0117] Optionally, in one embodiment, before step S140: injecting glue into each sealing area 214 until the glue fills the sealing area 214, the insulating oil and seawater in the sealing area 214 may be cleaned first. Specifically, the following steps are included:

[0118] S131: Connect the glue injection valve 251 located at the lower side of the sealing area 214 to the cleaning system;

[0119] Specifically, in one embodiment, the cleaning system may be a high-pressure air source or an air pump.

[0120] S132: Open the glue injection valve 251 and the glue discharge valve 252 located on the upper side of the sealing area 214;

[0121] S133: The cleaning system introduces dry air into the sealing area 214 through the glue injection valve 251 to clean the insulating oil and seawater in the sealing area 214;

[0122] S134 : Close the glue discharge valve 252 and the glue injection valve 251 in sequence, and disconnect the cleaning system from the glue injection valve 251 .

[0123] Specifically, dry air is first introduced into the sealing area 214 before glue injection, so as to clean out impurities such as insulating oil and seawater in the sealing area 214, avoid affecting subsequent glue injection, ensure the stability of the glue after curing, and thus ensure the sealing and repair effect.

[0124] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for plugging and repairing an oil-filled submarine cable, characterized in that: The following steps are involved: The outer sheath of the oil-filled submarine cable at the leaking point is peeled off to expose the armor layer; The main housing of the oil-filled submarine cable plugging device is sleeved over the armor layer of the oil-filled submarine cable at the leakage point, so that the sealing assembly in the main housing separates the space between the main housing and the oil-filled submarine cable into an oil leakage zone and at least one sealing zone located on both sides of the oil leakage zone along the axial direction of the main housing, and the leakage point is located within the oil leakage zone; Opening the oil drain valve located at the lower side of the oil drain area; injecting glue into each of the sealing areas until the glue fills the sealing area; Waiting for the glue to cure; Close the oil drain valve; The glue includes a high-penetration agent and a low-penetration agent, wherein the step of injecting glue into each of the sealing areas until the glue fills the sealing area includes: Connecting the glue injection valve located on the lower side of the sealing area to the glue injection system; Open the glue injection valve and the glue discharge valve located on the upper side of the sealing area; The glue injection system first injects the high-penetration agent into the sealing area at a first preset pressure; When the high permeability agent continues to flow out of the glue discharge valve for a first period of time, closing the glue discharge valve; The glue injection system maintains the pressure of the sealing area at a second preset pressure for a second period of time, and then opens the glue discharge valve; The glue injection system then injects the low-permeability agent into the sealing area at the first preset pressure; When the low-permeability agent continues to flow out of the debonding valve for the first period of time, closing the debonding valve; The glue injection system maintains the pressure of the sealing area at the second preset pressure for the second period of time, and then closes the glue injection valve.

2. The oil-filled submarine cable plugging and repairing method according to claim 1 is characterized in that ； The first preset pressure ranges from 0.2 MPa to 0.4 MPa; and / or the second preset pressure ranges from 0.5 MPa to 1 MPa.

3. The oil-filled submarine cable plugging and repairing method according to claim 1 is characterized in that ； The first time period is 10s-15s; and / or the second time period is 1min-3min.

4. The oil-filled submarine cable plugging and repairing method according to claim 1, characterized in that: The high permeability agent is fluorosilicone rubber, organic silica gel or polyurethane glue; and / or the low permeability agent is fluorosilicone rubber or silicone rubber.

5. The oil-filled submarine cable plugging and repairing method according to claim 1, characterized in that: The step of waiting for the glue to solidify comprises: The time for waiting for the glue to cure is greater than or equal to 4 hours.

6. The oil-filled submarine cable plugging and repairing method according to claim 5, characterized in that: After the step of closing the oil drain valve, the method further includes the following steps: Check the leakage of oil-filled submarine cables; If leakage still occurs, connecting shells are installed at both ends of the main shell so that the connecting shells are sleeved outside the armor layer of the oil-filled submarine cable, and the space between the connecting shells and the oil-filled submarine cable forms a sealed area; Injecting glue into the sealing area of the connection housing until the glue fills the sealing area; Wait for the glue in the connection housing to solidify.

7. The oil-filled submarine cable plugging and repairing method according to claim 6, characterized in that: After the step of waiting for the glue in the connection housing to solidify, the method further includes the following steps: Check the oil-filled submarine cable for leakage again; If leakage still occurs, install another connecting shell at the end of the connecting shell away from the main shell; Injecting glue into the sealing area of the added connection housing until the glue fills the sealing area; Wait for the glue in the installed connection housing to solidify.

8. The oil-filled submarine cable plugging and repairing method according to claim 1, characterized in that: Before the step of injecting glue into each of the sealing areas until the glue fills the sealing area, the following steps are also included: Connecting the glue injection valve located on the lower side of the sealing area to the cleaning system; Open the glue injection valve and the glue discharge valve located on the upper side of the sealing area; The cleaning system introduces dry air into the sealing area through the glue injection valve to clean the insulating oil and seawater in the sealing area; Close the glue discharge valve and the glue injection valve in sequence, and disconnect the cleaning system from the glue injection valve.

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