Method for plugging and repairing oil-filled submarine cable

Abstract

A method for plugging and repairing an oil-filled submarine cable, comprising the following steps: stripping off an outer sheath of a section of an oil-filled submarine cable (10) where a leakage point is located, so as to expose an armor layer (18); sleeving a main housing (21) of an oil-filled submarine cable plugging device on the armor layer (18) of the section of the oil-filled submarine cable (10) where the leakage point is located, such that a sealing assembly (22) in the main housing (21) separates, in the axial direction of the main housing (21), 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 each of both sides of the oil leakage area (213), and the leakage point is located in the oil leakage area (213); opening an oil discharge valve (23) located at the lower side of the oil leakage area (213); injecting a sealant into each of the sealing areas (214) until the sealing areas are filled with the sealant (214); waiting for the sealant to cure; and closing the oil discharge valve (23). The method for plugging and repairing an oil-filled submarine cable can plug leakages of the oil-filled submarine cable (10) without damaging the armor layer (18).

Description

Oil-filled cable plugging repair method TECHNICAL FIELD

[0001] The present application relates to the technical field of oil-filled cable repair, in particular to an oil-filled cable plugging repair method. BACKGROUND

[0002] The oil-filled cable is a kind of submarine cable that uses insulating oil as a pressurized fluid and enables the insulating oil to flow freely in the cable. After the oil-filled cable is damaged, the insulating oil inside the oil-filled cable will leak, which not only pollutes the seawater but also affects the stable operation of the power grid system.

[0003] At present, there are splicing repair, water isolation repair and plugging repair for repairing the oil-filled cable, among which the plugging repair forms a physical plugging outside the damaged point without repairing the body, and the plugging repair has the technical advantages of being simple, fast and low in cost.

[0004] At present, the plugging repair method for the oil-filled cable mostly refers to the plugging repair method for the submarine oil and gas pipeline. However, the traditional plugging repair method for the submarine oil and gas pipeline is not ideal for the plugging repair of the oil-filled cable. SUMMARY

[0005] Therefore, it is necessary to provide an oil-filled cable plugging repair method for improving the plugging repair effect of the oil-filled cable leakage.

[0006] The present application provides an oil-filled cable plugging repair method, which comprises the following steps:

[0007] The outer sheath of the section where the leakage point of the oil-filled cable is located is peeled off to expose the armored layer;

[0008] The main shell of the oil-filled cable plugging device is sleeved outside the armored layer of the section where the leakage point of the oil-filled cable is located, so that the sealing assembly in the main shell divides the space between the main shell and the oil-filled cable into an oil leakage area and at least one sealing area on each side of the oil leakage area along the axial direction of the main shell, and the leakage point is located in the oil leakage area;

[0009] The oil discharge valve located on the lower side of the oil leakage area is opened;

[0010] Glue is injected into each sealing area until the sealing area is filled with glue;

[0011] The glue is allowed to solidify;

[0012] The oil discharge valve is closed.

[0013] The technical solution is further described as follows:

[0014] In one of the embodiments, the step of injecting glue into each of the sealing areas until the glue fills the sealing areas comprises:

[0015] connecting a glue injection valve located at the lower side of the sealing area with a glue injection system;

[0016] opening the glue injection valve and a glue discharge valve located at the upper side of the sealing area;

[0017] injecting glue into the sealing area by the glue injection valve at a first preset pressure by the glue injection system;

[0018] closing the glue discharge valve after the glue continuously flows out of the glue discharge valve for a first time period;

[0019] closing the glue injection valve after the glue injection system continuously maintains the pressure in the sealing area for a second time period at a second preset pressure.

[0020] In one of the embodiments, the glue comprises a high permeability agent and a low permeability agent, the step of injecting glue into each of the sealing areas until the glue fills the sealing areas, closing the glue discharge valve after the glue continuously flows out of the glue discharge valve for a first time period, and closing the glue injection valve after the glue injection system continuously maintains the pressure in the sealing area for a second time period at a second preset pressure comprises:

[0021] injecting the high permeability agent into the sealing area at the first preset pressure by the glue injection system;

[0022] closing the glue discharge valve after the high permeability agent continuously flows out of the glue discharge valve for the first time period;

[0023] opening the glue discharge valve after the glue injection system continuously maintains the pressure in the sealing area for the second time period at the second preset pressure;

[0024] injecting the low permeability agent into the sealing area at the first preset pressure by the glue injection system;

[0025] closing the glue discharge valve after the low permeability agent continuously flows out of the glue discharge valve for the first time period;

[0026] closing the glue injection valve after the glue injection system continuously maintains the pressure in the sealing area for the second time period at the second preset pressure.

[0027] In one of the embodiments, 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 of the embodiments, the first time period is 10s-15s; and / or, the second time period is 1min-3min.

[0029] In one of the embodiments, the high permeation agent is fluorosilicone rubber, silicone rubber or polyurethane rubber; and / or, the low permeation agent is fluorosilicone rubber or silicone rubber.

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

[0031] The time of waiting for the glue to solidify is greater than or equal to 4h.

[0032] In one of the embodiments, the step of closing the oil discharge valve further comprises the following steps:

[0033] Checking the leakage of the oil-filled submarine cable;

[0034] If there is still leakage, a connecting shell is installed at both ends of the main shell, the connecting shell is sleeved outside the armor layer of the oil-filled submarine cable, and a sealed area is formed between the connecting shell and the oil-filled submarine cable;

[0035] Injecting glue into the sealed area of the connecting shell until the sealed area is filled with the glue;

[0036] Waiting for the glue in the connecting shell to solidify.

[0037] In one of the embodiments, the step of waiting for the glue in the connecting shell to solidify further comprises the following steps:

[0038] Checking the leakage of the oil-filled submarine cable again;

[0039] If there is still leakage, another connecting shell is installed at the end of the connecting shell away from the main shell;

[0040] Injecting glue into the sealed area of the installed connecting shell until the sealed area is filled with the glue;

[0041] Waiting for the glue in the installed connecting shell to solidify.

[0042] In one of the embodiments, before the step of injecting glue into each of the sealed areas until the sealed area is filled with the glue; the oil-filled submarine cable plugging repair method further comprises:

[0043] Connecting the glue injection valve located at the lower side of the sealed area with the cleaning system;

[0044] Opening the glue injection valve and the glue discharge valve located at the upper side of the sealed 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] The glue injection valve and the glue injection valve are closed in sequence, and the connection between the cleaning system and the glue injection valve is disconnected.

[0047] In the above oil-filled submarine cable plugging and repairing method, the outer sheath of the section where the leakage point of the oil-filled submarine cable is located is first stripped to expose the armor layer, and then a main shell is provided outside the armor layer, so that the sealing assembly in the main shell divides the space between the main shell and the oil-filled submarine cable into an oil leakage area and at least one sealing area on each side of the oil leakage area, and the leakage point is located in the oil leakage area. Therefore, the leaked insulating oil can be discharged from the oil leakage area through the oil discharge valve, greatly reducing the possibility of insulating oil leakage into the sealing area, thereby preventing the glue in the sealing area from being washed away by the oil, and ensuring the stability of the subsequent glue injection process into the sealing area. Therefore, the glue injection can be carried out simultaneously during the oil discharge, thereby improving the efficiency of the plugging and repairing. At the same time, by injecting glue into the sealing area at a certain pressure, the glue can penetrate to the outside of the PE layer along the copper strip gap of the armor layer and the gap between the armor layer and the PE layer under pressure to fill the copper strip gap of the armor layer and the gap between the armor layer and the PE layer. Thus, the possibility of axial leakage of insulating oil along the copper strip gap of the armor layer and the gap between the armor layer and the PE layer is avoided, thereby achieving leakage plugging of the part of the oil-filled submarine cable outside the PE layer without damaging the armor layer. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The accompanying drawings do not constitute an inappropriate limitation on the present application.

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0050] In addition, the drawings are not drawn to scale 1:1, and the relative sizes of the various elements are only exemplarily drawn in the drawings, but not necessarily drawn in true proportion. In the drawings:

[0051] Fig. 1 is a structural schematic view of an oil-filled submarine cable according to an embodiment.

[0052] Fig. 2 is a structural schematic view of an oil-filled submarine cable plugging and repairing device according to an embodiment.

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

[0054] FIG. 4 is a flowchart of a method for repairing a blocked oil-filled submarine cable according to an embodiment.

[0055] Reference signs: 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 housing; 211, first half housing; 212, second half housing; 213, oil leakage area; 214, sealing area; 22, sealing assembly; 221, sealing strip; 222, annular sealing gasket; 23, oil discharge valve; 251, glue injection valve; 252, glue discharge valve; 30, joint housing. DETAILED DESCRIPTION

[0056] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the spirit of the present application, and that the present application is not limited to the specific embodiments disclosed below.

[0057] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0058] In addition, if there are terms such as "first", "second", these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In the present application, unless specifically defined otherwise, if there are terms such as "mount", "connect", "connect", "fix" and the like, these terms should be understood in a broad sense. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0060] In the present application, unless specifically defined otherwise, if there are similar descriptions such as "on" or "below" the first feature of the second feature, it means that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0061] It should be noted that if an element is referred to as "fixed to" or "provided to" another element, it can be directly on another element or there can be a middle element. If an element is considered to be "connected" to another element, it can be directly connected to another element or there can be a middle element. If present, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in the present application are for illustrative purposes only and are not the only embodiment.

[0062] As described above, the conventional plugging and repairing method for the subsea oil and gas pipeline is not ideal for the plugging and repairing of the oil-filled submarine cable 10. The inventors have found through extensive research that the reason is that the structure of the oil-filled submarine cable 10 is very different from that of the subsea oil and gas pipeline. Specifically, referring to FIG. 1, the through-slot oil-filled submarine cable 10 includes an oil channel 11, a conductor layer 12, an insulation layer 13, a lead sheath 14, a first non-woven cloth layer 15, a PE layer 16, a second non-woven cloth layer 17, an armor layer 18 and an outer sheath (not shown) which are sequentially sleeved from inside to outside. The gap between the armor layer 18, the PE layer 16 and the outer sheath is large, and the armor layer 18 is a cylindrical structure composed of a plurality of copper strips arranged closely in the circumferential direction, and there are also axial gaps between the copper strips. Thus, when 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, and between the copper strip gaps of the armor layer 18.

[0063] The current plugging repair method cannot plug the gap between the armor layer 18, the PE layer 16 and the outer protective layer, and cannot solve the axial leakage problem of the oil-filled submarine cable 10. To achieve plugging, the submarine cable armor layer 18 can only be damaged to implement plugging from the surface of the submarine cable PE layer 16. After the submarine cable armor layer 18 is damaged, the oil-filled submarine cable 10 loses the ability to withstand tensile load. Considering the actual working condition of the oil-filled submarine cable 10, the axial load of the oil-filled submarine cable 10 is inevitable. Therefore, it is urgent to research an effective plugging method for the oil leakage of the oil-filled submarine cable 10.

[0064] Based on this, an embodiment of the present application provides an oil-filled submarine cable 10 plugging repair method for solving 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, the oil-filled submarine cable 10 plugging repair device used by the oil-filled submarine cable 10 plugging repair method in an embodiment is briefly introduced. Specifically, referring to FIGS. 2 and 3, the oil-filled submarine cable 10 plugging repair device of an embodiment includes a main shell 21 and a sealing assembly 22. The main shell 21 is used to be sleeved on the segment of the oil-filled submarine cable 10 where the leakage point is located. The sealing assembly 22 is arranged in the main shell 21. The sealing assembly 22 is used to divide the space between the main shell 21 and the oil-filled submarine cable 10 into a leakage oil area 213 corresponding to the leakage point and each at least one sealing area 214 located on both sides of the leakage oil area 213 along the axial direction of the main shell 21. The leakage oil area 213 is communicated with an oil discharge valve 23. Exemplarily, the oil discharge valve has two, one of which is located on the lower side of the leakage oil area 213. Each sealing area 214 is provided with a glue injection valve 251 and a glue discharge valve 252, and the glue injection valve 251 and the glue discharge valve 252 are arranged opposite along the radial direction of the main shell 21. The glue injection valve 251 is located below the glue discharge valve 252.

[0065] Specifically, referring to FIG. 4, the oil-filled submarine cable 10 plugging repair method of an embodiment includes the following steps:

[0066] S110: The outer protective layer of the segment of the oil-filled submarine cable 10 where the leakage point is located is peeled off to expose the armor layer 18;

[0067] S120: The main shell 21 is sleeved on the armor layer 18 of the segment of the oil-filled submarine cable 10 where the leakage point is located, so that the sealing assembly 22 in the main shell 21 divides the space between the main shell 21 and the oil-filled submarine cable 10 into the leakage oil area 213 and each at least one sealing area 214 located on both sides of the leakage oil area 213 along the axial direction of the main shell 21, and the leakage point is located in the leakage oil area 213;

[0068] Specifically, referring to FIG. 1, in an embodiment, the main housing 21 comprises a first half housing 211 and a second half housing 212, which are oppositely connected and jointly form a cylindrical structure. During installation, the first half housing 211 and the second half housing 212 are oppositely sleeved on the segment of the oil-filled submarine cable 10 where the leakage point is located. Then, the first half housing 211 and the second half housing 212 are locked, and the installation of the main housing 21 is completed.

[0069] Referring to FIG. 2, the sealing assembly 22 comprises a sealing strip 221 and at least two annular sealing pads 222. The sealing strip 221 is arranged in the joint gap between the first half housing 211 and the second half housing 212, thereby sealing the joint gap between the first half housing 211 and the second half housing 212 and preventing the insulation oil or glue from leaking therefrom. Further, all the annular sealing pads 222 are arranged along the axial direction of the main housing 21 between the main housing 21 and the oil-filled submarine cable 10 and are in sealing cooperation with the main housing 21 and the oil-filled submarine cable 10, so as to divide the space between the main housing 21 and the oil-filled submarine cable 10 into the oil leakage area 213 and at least one sealing area 214 on each side of the oil leakage area 213.

[0070] S130: opening the oil discharge valve 23 located on the lower side of the oil leakage area 213;

[0071] Specifically, the oil leakage area 213 is communicated with two oil discharge valves 23, which are oppositely arranged along the radial direction of the main housing 21. During oil discharge, the lower oil discharge valve 23 is opened. Since the density of the insulation oil is smaller than that of seawater, the seawater can be discharged while the insulation oil is discharged.

[0072] S140: injecting glue into each sealing area 214 until the sealing area 214 is filled with glue;

[0073] Specifically, the glue can be injected into the sealing area 214 by an underwater glue injection system.

[0074] S150: waiting for the glue to solidify;

[0075] S160: closing the oil discharge valve 23.

[0076] In the plugging repair method of the oil-filled submarine cable 10, the outer sheath of the section where the leakage point of the oil-filled submarine cable 10 is located is first stripped to expose the armored layer 18, and then the main shell 21 is sleeved outside the armored layer 18, so that the sealing assembly 22 in the main shell 21 divides the space between the main shell 21 and the oil-filled submarine cable 10 into the oil leakage area 213 and each at least one sealing area 214 located on both sides of the oil leakage area 213, and the leakage 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 leakage into the sealing area 214, thereby preventing the glue in the sealing area 214 from being washed away by oil, ensuring the stability of the subsequent glue injection process in the sealing area 214, and thus enabling synchronous glue injection during oil discharge, thereby improving the efficiency of plugging repair. At the same time, by injecting glue into the sealing area 214 at a certain pressure, the glue can penetrate to the outside of the PE layer 16 along the copper strip gap of the armored layer 18 and the gap between the armored layer 18 and the PE layer 16 under pressure to fill the copper strip gap of the armored layer 18 and the gap between the armored layer 18 and the PE layer 16, thereby avoiding the possibility of axial leakage of insulating oil along the copper strip gap of the armored layer 18 and the gap between the armored layer 18 and the PE layer 16, and achieving leakage plugging of the part of the oil-filled submarine cable 10 outside the PE layer 16 without damaging the armored layer 18.

[0077] In an embodiment, the step of step S140 comprises the following steps:

[0078] S141: connecting the glue injection valve 251 located at the lower side of the sealing area 214 to the glue injection system;

[0079] S142: opening the glue injection valve 251 and the glue discharge valve 252 located at the upper side of the sealing area 214;

[0080] S143: the glue injection system injects glue into the sealing area 214 through the glue injection valve 251 at a first preset pressure;

[0081] Specifically, each sealing area 214 is provided with a glue injection valve 251 and a glue discharge valve 252, and the glue injection valve 251 and the glue discharge valve 252 are oppositely arranged along the radial direction of the main shell 21, and the glue injection valve 251 is located below the glue discharge valve 252. The glue injection system injects glue into the sealing area 214 from bottom to top through the glue injection valve 251, and since the density of the sealing glue is greater than that of seawater, injecting glue from bottom to top can ensure that the seawater in the sealing area 214 can be discharged from the glue discharge valve.

[0082] Exemplarily, in an embodiment, the first preset pressure ranges from 0.2 Mpa to 0.4 Mpa. Specifically, the first preset pressure is too small to inject the glue into the sealing area 214, and the first preset pressure is too large to easily exceed the safe pressure range of the oil-filled submarine cable 10 and increase the cost. By configuring the range of the first preset pressure to be 0.2 Mpa to 0.4 Mpa, the glue can be smoothly injected into the sealing area 214 at a lower cost.

[0083] S144: When the glue outlet valve 252 continuously flows out the glue for a first time period, the glue outlet valve 252 is closed.

[0084] Exemplarily, in an embodiment, the first time period is 10 s to 15 s. When the glue outlet valve 252 continuously flows out the glue for 10 s to 15 s, it indicates that the sealing area 214 has been filled with the glue, ensuring that the seawater is completely discharged, and improving the sealing effect of the glue in the sealing area 214.

[0085] S145: After the glue injection system continuously pressurizes the sealing area 214 at a second preset pressure for a second time period, the glue injection valve 251 is closed.

[0086] Specifically, after the glue outlet valve 252 is closed, by continuing to pressurize the sealing area 214 for a period of time, it can be ensured that the glue fully penetrates into the copper strip gap of the armor layer 18 and the gap between the armor layer 18 and the PE layer 16 to fill the copper strip gap of the armor layer 18 and the gap between the armor layer 18 and the PE layer 16, avoiding the possibility of axial leakage of the insulating oil along the copper strip gap of the armor layer 18 and the gap 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 is solidified, improving the sealing effect.

[0087] Exemplarily, in an embodiment, the second preset pressure ranges from 0.5 MPa to 1 MPa. Specifically, the installation of the oil-filled submarine cable 10 plugging device will have a certain extrusion effect on the oil-filled submarine cable 10. In order to ensure that the externally applied pressure borne by the oil-filled submarine cable 10 is within its safe bearing range, it is necessary to analyze the safe bearing stability range of the oil-filled submarine cable 10 through theory and experiment. Through simulation analysis, when the externally applied pressure of the oil-filled submarine cable 10 is 2 MPa, the maximum equivalent stress of the PE layer 16 of the oil-filled submarine cable 10 exceeds the yield limit of the material, at which time the PE layer 16 of the oil-filled submarine cable 10 may yield. At the same time, through experimental analysis, when the oil-filled submarine cable 10 bears a non-uniform radial pressure of 2.0 MPa, the lead sheath 14 of the oil-filled submarine cable 10 will reach the yield limit and deform. Therefore, the present inventors set the upper limit of the second preset pressure to be no more than 1 MPa in combination with theoretical and experimental analysis. At the same time, if the second preset pressure is too low, the glue cannot penetrate into the gap between the copper strip of the armored layer 18 and the PE layer 16, and the pressure in the sealing area 214 after the curing of the sealing agent cannot be guaranteed, and the plugging effect is poor. Therefore, the present inventors set the lower limit of the second preset pressure to be greater than 0.5 MPa in combination with theoretical and experimental analysis.

[0088] Further, the second time period, i.e., the time for continuously pressurizing the sealing area 214, ranges from 1 min to 3 min. Specifically, if the pressurizing time is too short, it cannot achieve good results, and if the pressurizing time is too long, it will increase the cost. By configuring the pressurizing time to be 1 min to 3 min, the pressurizing effect is guaranteed while the cost is reasonably controlled.

[0089] Optionally, in an embodiment, the glue used in the oil-filled submarine cable 10 plugging and repairing method includes a high-permeability agent and a low-permeability agent. Based on this, in an embodiment, the steps S143 to S145 specifically include the following steps:

[0090] S1431: The glue injection system first injects the high-permeability agent into the sealing area 214 at a first preset pressure;

[0091] S1432: When the glue discharge valve 252 continuously discharges the high-permeability agent for a first time period, the glue discharge valve 252 is closed;

[0092] S1433: After the glue injection system continuously pressurizes the sealing area 214 at a second preset pressure for a second time period, the glue discharge valve 252 is opened again;

[0093] S1434: The glue injection system injects the low-permeability agent into the sealing area 214 at the first preset pressure again;

[0094] S1435: When the glue discharge valve 252 continuously discharges the low-permeability agent for a first time period, the glue discharge valve 252 is closed;

[0095] S1436: The glue injection system continues to pressurize the sealing area 214 at the second preset pressure for a second time period, and then closes the glue injection valve 251.

[0096] Specifically, the high permeation agent is a sealant with low viscosity and can penetrate into the tiny gap, and after solidification, it can achieve the purpose of sealing and preventing leakage. The low permeation agent is a material with excellent elasticity and flexibility, and the low permeation agent is not easy to enter the tiny gap, but has the effect of filling and pressure maintaining, and can balance the pressure of the insulating oil leaked from the oil-filled submarine cable 10. By first injecting the high permeation agent into the sealing area 214 and maintaining the pressure for a certain time, and then injecting the low permeation agent to replace the high permeation agent and maintaining the pressure for a certain time, the high permeation agent injected first is more likely to penetrate into the copper strip gap of the armored layer 18 and the gap between the armored layer 18 and the PE layer 16. After the low permeation agent replaces the high permeation agent, the low permeation agent can balance the pressure of the insulating oil leaked from the oil-filled submarine cable 10, and at the same time, it can prevent the high permeation agent after solidification from being squeezed out of the gap between the layers. In this way, the plugging and repairing effect is further improved.

[0097] Optionally, in an embodiment, the high permeation agent includes but is not limited to fluorosilicone rubber, silicone rubber or polyurethane glue, etc. For example, in an embodiment, fluorosilicone gel with a density of about 1.27 g / mm3 can be used as a high permeation sealant. Optionally, in an embodiment, the low permeation agent can be fluorosilicone rubber or silicone rubber.

[0098] Specifically, the step of waiting for the glue to solidify includes the following steps:

[0099] S151: The waiting time for the glue to solidify is greater than or equal to 4h.

[0100] Specifically, the solidification time of not less than 4h can ensure that the glue is fully solidified, and the plugging and repairing effect after the glue is solidified is guaranteed.

[0101] Optionally, referring to FIG. 2 and FIG. 3, in an embodiment, the step of closing the oil discharge valve 23 further includes the following steps:

[0102] S161: Check the leakage of the oil-filled submarine cable 10;

[0103] Specifically, whether the insulating oil leaks out of the two ends of the main shell 21 can be observed by an instrument or the naked eye.

[0104] S162: If there is still leakage, a joint shell 30 is added at both ends of the main shell 21, so that the joint shell 30 is sleeved outside the armored layer 18 of the oil-filled submarine cable 10, and the space between the joint shell 30 and the oil-filled submarine cable 10 forms a sealing area 214.

[0105] Specifically, the structure of the jointing shell 30 is a cylindrical structure, the jointing shell 30 is sealingly connected with the main shell 21, and the jointing shell 30 is also provided with a sealing assembly 22, which seals and encloses the space between the jointing shell 30 and the oil-filled submarine cable 10 to form a sealed area 214.

[0106] S163: injecting glue into the sealed area 214 of the jointing shell 30 until the glue fills the sealed area 214;

[0107] Specifically, further, the sealed area 21433 of each jointing shell 30 is also communicated with a glue injection valve 251 and a glue discharge valve 252. Further, the step of injecting glue into the sealed area 214 of the jointing shell 30 can refer to the above-mentioned steps S1431 to S1436 of injecting glue into the sealed area 214 of the main shell 21, which will not be repeated here.

[0108] S164: waiting for the glue in the jointing shell 30 to solidify.

[0109] Specifically, when the plugging effect of the main shell 21 is not good, by adding the jointing shell 30 at the end of the main shell 21, the number of sealed areas 214 in the axial direction of the main shell 21 can be increased, and by injecting glue into the sealed area 21433 of the jointing shell 30, the effect of axial sealing can be enhanced, and axial leakage can be avoided.

[0110] Further, in an embodiment, after step S164, the following steps are further included:

[0111] S165: checking the leakage of the oil-filled submarine cable 10 again:

[0112] S167: if there is still leakage, another jointing shell is installed at the end of the jointing shell 30 away from the main shell 21;

[0113] S168: injecting glue into the sealed area 214 of the installed jointing shell 30 until the glue fills the sealed area 214;

[0114] S169: waiting for the glue in the installed jointing shell 30 to solidify.

[0115] Specifically, the installation method of the installed jointing shell 30 and the glue injection method of the installed jointing shell 30 can refer to the above-mentioned steps S161 to S164, which will not be repeated here. Further, the steps S165 to S169 are repeated until there is no leakage of the oil-filled submarine cable 10, so as to ensure that the leakage of the oil-filled submarine cable 10 is completely plugged and repaired.

[0116] Optionally, in an embodiment, before step S140: injecting glue into each sealed area 214 until the glue fills the sealed area 214, the insulating oil and seawater in the sealed area 214 can be cleaned first. Specifically, the following steps are included:

[0117] S131: connecting the glue injection valve 251 located at the lower side of the sealing area 214 with the cleaning system;

[0118] Specifically, in an embodiment, the cleaning system can be a high-pressure air source or an air pump.

[0119] S132: opening the glue injection valve 251 and the glue discharge valve 252 located at the upper side of the sealing area 214;

[0120] 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;

[0121] S134: sequentially closing the glue discharge valve 252 and the glue injection valve 251, and disconnecting the cleaning system from the glue injection valve 251.

[0122] Specifically, before glue injection, dry air is first introduced into the sealing area 214, so that the insulating oil and seawater and other impurities in the sealing area 214 can be cleaned thoroughly, avoiding affecting the subsequent glue injection, ensuring the stability of the glue after solidification, and further ensuring the plugging and repairing effect.

[0123] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not contradict, they should be considered as the scope of the present application.

[0124] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of the patent protection of the present application should be subject to the appended claims.

Claims

1. An oil-filled submarine cable sealing repair method, characterized by, The method comprises the following steps: peeling the outer sheath of the segment where the leakage point of the oil-filled submarine cable is located to expose the armored layer; sleeving the main shell of the oil-filled submarine cable sealing device outside the armored layer of the segment where the leakage point of the oil-filled submarine cable is located, so that the sealing assembly 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 on each side of the oil leakage area along the axial direction of the main shell, and the leakage point is located in the oil leakage area; opening the oil discharge valve located on the lower side of the oil leakage area; injecting glue into each sealing area until the sealing area is filled with glue; waiting for the glue to solidify; closing the oil discharge valve; the glue comprises a high-permeability agent and a low-permeability agent, wherein the step of injecting glue into each sealing area until the sealing area is filled with glue comprises: connecting the glue injection valve located on the lower side of the sealing area to the glue injection system; opening 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-permeability agent into the sealing area at the first preset pressure; when the glue discharge valve continuously discharges the high-permeability agent for the first time period, the glue discharge valve is closed; after the glue injection system continuously pressurizes the sealing area at the second preset pressure for the second time period, the glue discharge valve is opened again; the glue injection system again injects the low-permeability agent into the sealing area at the first preset pressure; when the glue discharge valve continuously discharges the low-permeability agent for the first time period, the glue discharge valve is closed; after the glue injection system continuously pressurizes the sealing area at the second preset pressure for the second time period, the glue injection valve is closed again.

2. The method of claim 1, wherein ； 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 method of claim 1, wherein ； The first time period is 10 s to 15 s; and / or, the second time period is 1 min to 3 min.

4. The oil-filled cable patching and repairing method according to claim 1, characterized by, The high-permeability agent is fluorosilicone rubber, silicone glue, or polyurethane glue; and / or, the low-permeability agent is fluorosilicone rubber or silicone rubber.

5. The method of claim 1, wherein, The step of waiting for the glue to solidify comprises: The waiting time for the glue to solidify is greater than or equal to 4 h.

6. The method of claim 5, wherein the oil-filled submarine cable is a power cable. After the step of closing the oil discharge valve, the following steps are further included: checking the leakage of the oil-filled submarine cable; if there is still leakage, a connecting shell is installed at both ends of the main shell, the connecting shell is sleeved outside the armored layer of the oil-filled submarine cable, and a sealing area is formed between the connecting shell and the oil-filled submarine cable; injecting glue into the sealing area of the connecting shell until the sealing area is filled with glue; waiting for the glue in the connecting shell to solidify.

7. The method of claim 6, wherein the oil-filled submarine cable is a power cable. After the step of waiting for the glue in the connecting shell to solidify, the following steps are further included: checking the leakage of the oil-filled submarine cable again; if there is still leakage, another connecting shell is installed at the end of the connecting shell away from the main shell; injecting glue into the sealing area of the installed connecting shell until the sealing area is filled with glue; waiting for the glue in the installed connecting shell to solidify.

8. The method of claim 1, wherein, Before the step of injecting glue into each of the sealing areas until the glue fills the sealing areas, the method further comprises the steps of: connecting a glue injection valve located at the lower side of the sealing area to a cleaning system; opening the glue injection valve and a glue discharge valve located at the upper side of the sealing area; the cleaning system passing dry air into the sealing area through the glue injection valve to clean the insulating oil and seawater in the sealing area; sequentially closing the glue discharge valve and the glue injection valve, and disconnecting the cleaning system from the glue injection valve.

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