Cable multi-effect combined injection type repairing method, repairing liquid and preparation method

Abstract

The invention provides a cable multi-effect combined injection type repairing method, repairing liquid and a preparation method, and relates to the technical field of cable repairing. The method comprises the steps that a repairing groove is formed in a specific section of the cable, and a water blocking buffer layer and a main insulating layer of the specific section have defects; repairing liquid is injected into the cable through the repairing groove in a pressurization mode, and the repairing liquid has the conductive characteristic, the targeted induction characteristic and the permeability characteristic; after the repairing groove is blocked, under the condition that the power transmission state of the cable is recovered, the repairing liquid permeates and diffuses through the water-blocking buffer layer, and then the main insulating layer is infiltrated, so that the defects of the water-blocking buffer layer and the main insulating layer are repaired at the same time. According to the mode, the repairing liquid can permeate and diffuse in the water-blocking buffer layer and the main insulating layer in sequence, so that the main insulating layer is repaired by the main insulating repairing component while the water-blocking buffer layer is repaired by the buffer layer repairing component, the effects of local accurate repairing and simultaneous multi-effect repairing are achieved, and the service life of the water-blocking buffer layer and the main insulating layer is prolonged. And the construction efficiency and the action effect of cable repair can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of cable repair technology, and more specifically, to a multi-effect combined injection repair method and apparatus for cables. Background Technology

[0002] As an indispensable and crucial component of power transmission lines, the reliability of power cables plays a decisive role in the stability and safety of the entire power system. Cross-linked polyethylene (XLPE) power cables, due to their excellent electrical and mechanical properties, are widely used in my country's power system, accounting for a large proportion of the market, with many cable lines having been in operation for over 20 years. To ensure the safe operation of transmission lines, cables with severe insulation problems can be replaced entirely, or hidden defects in the XLPE insulation can be repaired to extend the service life of the cable insulation. However, replacing the entire cable would consume enormous human, material, and financial resources, failing to meet the requirements of cost reduction and efficiency improvement. Power cable insulation repair technology, under limited cost conditions, can effectively repair defects in cables, enhance the insulation of existing aging power cable lines, and significantly extend their service life, possessing significant economic and social value.

[0003] Currently, erosion defects in the buffer layer of high-voltage power cables and the resulting cable breakdown faults occur frequently. Some studies have reported injection-type repair methods using graphite powder or organic solvents to carry conductive media. These repair methods involve drilling several small holes through the cable's outer sheath and metal sheath, and then injecting the repair fluid into the buffer layer under pressure. However, this method only works on the buffer layer and has limited effect on the overall insulation of old high-voltage cables. Summary of the Invention

[0004] Firstly, the purpose of this application is to provide a multi-effect combined injection repair method for cables, which can overcome the defects of the existing methods.

[0005] Secondly, another objective of this application is to provide a repair fluid that enables the aforementioned multi-effect combined injection repair method for cables via external injection.

[0006] Thirdly, another objective of this application is to provide a method for preparing the above-mentioned repair liquid, which enables the repair liquid to simultaneously repair defects in both the water-blocking buffer layer and the main insulating layer.

[0007] The embodiments of this application are implemented as follows: Firstly, this application provides a multi-effect combined injection repair method for cables, mainly including: A repair groove is provided in a specific section of the cable. Both the water-blocking buffer layer and the main insulation layer at the specific section location have defects. The repair groove passes through the outer sheath and the metal sheath in sequence. The groove sidewall away from the outer sheath is located on the side of the water-blocking buffer layer close to the metal sheath. Repair fluid is injected into the cable through the repair groove under pressure. The repair fluid has conductive, targeted induction and penetrating properties. The repair fluid contains a main insulation repair component and a buffer layer repair component. The main insulation repair component and the buffer layer repair component are mutually stable under given conditions. After sealing the repair groove, when the cable is put back into use and powered on, the repair liquid permeates and diffuses through the water-blocking buffer layer and then wets the main insulation layer, thus simultaneously repairing the defects in the water-blocking buffer layer and the main insulation layer.

[0008] Secondly, this application provides a repair solution, which comprises the following components by weight: The main insulation repair component comprises 35 to 40 parts, the buffer layer repair component comprises 25 to 30 parts, the flowability modification component comprises 10 to 15 parts, the conductivity improvement component comprises 8 to 12 parts, the main insulation repair catalyst comprises 1 to 3 parts, and the buffer layer repair catalyst comprises 1 to 2 parts; the main insulation repair component has targeted induction characteristics and penetration characteristics.

[0009] Thirdly, this application provides a method for preparing a repair solution, mainly comprising: Mix the main insulation repair component, buffer layer repair component, flowability modification component, and conductivity improvement component according to the weight proportions to obtain mixture one; According to the preset mixing time, the main insulation repair catalyst and the buffer layer repair catalyst are added sequentially in parts by weight to the mixture to obtain the repair solution.

[0010] The embodiments of this application have at least the following advantages or beneficial effects: This multi-effect injection-type cable repair method involves drilling holes from the outside of the cable inward to form a repair groove, injecting repair fluid into the cable. Under the action of a specific electric field, the dielectric induces the repair fluid to penetrate and diffuse sequentially in the water-blocking buffer layer and the main insulation layer. This allows the buffer layer repair component to repair the water-blocking buffer layer while the main insulation repair component repairs the main insulation layer, achieving both localized precise repair and simultaneous multi-effect repair. This method can effectively improve the construction efficiency and effectiveness of cable repair. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 A schematic diagram of the multi-effect combined injection repair method for cables provided in this application; Figure 2 A schematic diagram of the high-voltage cross-linked polyethylene power cable structure and a schematic diagram of the repair groove setting method provided in this application; Figure 3 This is a schematic diagram showing the location of the repair groove provided in this application; Figure 4 A schematic diagram of the multi-effect combined injection repair device for cables provided in this application; Figure 5 A schematic diagram of the cable multi-effect combined injection repair device provided in this application in its use state.

[0013] Icons: 1. Injection nozzle; 2. Control valve; 3. Flow meter; 4. Protection valve; 5. Liquid storage tank; 6. Air compressor; 7. Repair tank; 8. Outer sheath; 9. Metal sheath; 10. Water-blocking buffer layer; 11. Main insulation layer; 111. Insulation shielding layer; 112. Cross-linked polyethylene layer; 113. Conductor shielding layer; 12. Cable core. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Generally, the components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0015] Please refer to Figures 1 to 3 One embodiment of this application provides a method for repairing the main insulation of a high-voltage power cable via external injection, mainly including: Step 102: A repair groove is set in a specific section of the cable. Both the water-blocking buffer layer and the main insulation layer at the specific section location have defects. The repair groove passes through the outer sheath and the metal sheath in sequence. The groove sidewall away from the outer sheath is set on the side of the water-blocking buffer layer close to the metal sheath. Step 104: Inject repair fluid into the cable through the repair groove under pressure. The repair fluid has conductive, targeted induction and penetrating properties. The repair fluid contains a main insulation repair component and a buffer layer repair component. The main insulation repair component and the buffer layer repair component are in a stable state under given conditions. Step 106: After sealing the repair groove, when the cable is in a powered-on state for use, the repair liquid permeates and diffuses through the water-blocking buffer layer and then wets the main insulation layer to simultaneously repair the defects in the water-blocking buffer layer and the main insulation layer.

[0016] It should be noted that, to avoid confusion between parameters and structural labels, no labels are used in this embodiment.

[0017] In this embodiment, the cable includes, from the inside out, a cable core, a main insulation layer, a water-blocking buffer layer, a metal sheath, and an outer sheath.

[0018] In this embodiment, the main insulation repair component has targeted induction characteristics. Specifically, under a specific electric field, the main insulation repair component can concentrate and diffuse into areas with higher electric fields. In other words, under specific electric field conditions, the main insulation repair component can gradually penetrate into the main insulation layer through the water-blocking buffer layer. When it encounters water or active groups in damp, cracked, or water-tree areas, it undergoes a condensation reaction, eliminating moisture in the main insulation layer and filling insulation defects, thereby repairing the insulation layer of old cables and extending the cable's lifespan.

[0019] Specifically, the above method involves drilling holes from the outside of the cable inward to form a repair groove, injecting repair fluid into the cable. Under the action of a specific electric field, the dielectric induces the repair fluid to penetrate and diffuse sequentially in the water-blocking buffer layer and the main insulation layer. This allows the buffer layer repair component to repair the water-blocking buffer layer while the main insulation repair component repairs the main insulation layer, achieving both localized precise repair and simultaneous multi-effect repair. This effectively improves the construction efficiency and effectiveness of cable repair.

[0020] It should be noted that, compared with existing technologies, the above method does not require the cable to be out of service; that is, the method can be used to repair the cable in situ. The cable only needs to be de-energized during repair, significantly shortening the time required to restore the cable to a usable state. Furthermore, the pressurization area of ​​the above method is a localized area of ​​the defective main insulation layer, rather than the entire cable or a section of cable. Therefore, when repairing cables using this method, it is not necessary to remove both ends of the cable. Moreover, the pressurization repair method will not cause irreversible structural damage to old or micro-cracked areas of the cable. In addition, the above method can simultaneously repair defects in localized areas of both the main insulation layer and the water-blocking buffer layer, providing multi-effect repair.

[0021] In this embodiment, the defects in the main insulation layer and the water-blocking buffer layer do not need to be defects in the same vertical position. They can be defects in different locations that are not vertically corresponding within a certain area (i.e., a specific section of the cable).

[0022] In this embodiment, the sidewall of the repair groove away from the outer sheath is located at a depth of 1 / 3 to 1 / 2 of the water-blocking buffer layer from the outer sheath toward the cable core.

[0023] In this embodiment, the pressurization pressure is 0.15 MPa to 0.18 MPa, and the injection time of the repair fluid is 20 min to 30 min. In this embodiment, the main insulation layer, from the outside to the inside (from the outer sheath to the cable core), sequentially includes an insulating shielding layer, a cross-linked polyethylene layer, and a conductor shielding layer. Under the action of dielectric properties, the main insulation repair component diffuses from the water-blocking buffer layer toward the conductor shielding layer. Under the action of penetration concentration difference and pressure, the buffer layer repair component diffuses from the side of the water-blocking buffer layer near the metal sheath toward the side of the water-blocking buffer layer near the main insulation layer.

[0024] In this embodiment, the above-mentioned repair fluid can be induced to diffuse in an electric field with a working frequency of 50Hz, or it can be induced to diffuse in an electric field under normal power supply to locally repair the main insulation layer of the cable.

[0025] In this embodiment, the above-mentioned repair method of injecting repair fluid on the outside of the cable can carry out high-voltage tests under normal power transmission procedures, and can be put into power transmission after passing the test. Based on the previous embodiment, another embodiment of this application provides a repairing night, which comprises the following components by weight: The main insulation repair component comprises 35 to 40 parts, the buffer layer repair component comprises 25 to 30 parts, the flowability modification component comprises 10 to 15 parts, the conductivity improvement component comprises 8 to 12 parts, the main insulation repair catalyst comprises 1 to 3 parts, and the buffer layer repair catalyst comprises 1 to 2 parts; the main insulation repair component has targeted induction characteristics and penetration characteristics.

[0026] Specifically, the aforementioned main insulation repair component and the aforementioned buffer layer repair component do not react under mixing and injection conditions and are both in a stable state. The aforementioned main insulation repair component can penetrate and diffuse sequentially in the water-blocking buffer layer and the main insulation layer. The aforementioned flowability modification component can further improve the penetration characteristics of the main insulation repair component. The aforementioned buffer layer repair component can meet the requirements of good flowability to ensure a smooth injection process. Moreover, the aforementioned buffer layer repair component can gradually form a product with higher viscosity through a condensation reaction after a certain injection time, which adheres to the relatively loose buffer layer (fiber woven material). The aforementioned conductivity improvement component can effectively improve the conductivity of the repaired water-blocking buffer layer to meet the conductivity requirements of the buffer layer.

[0027] In this embodiment, after the catalyst for main insulation repair and the catalyst for buffer layer repair are added sequentially, the catalyst for main insulation repair reacts with the main insulation repair component, and the catalyst for buffer layer repair reacts with the buffer layer repair component. The two reactions do not interfere with each other. In this embodiment, the main insulation repair component is composed of trimethylmethoxysilane, or of trimethylmethoxysilane and methylphenyldimethoxysilane. The mass percentage of trimethylmethoxysilane in the main insulation repair component is not less than 70%, and the mass percentage of trimethylmethoxysilane in the repair solution is not less than 30%.

[0028] By setting a content of small-molecule siloxane at a predetermined mass ratio, the main insulation repair component can possess good penetration and diffusion characteristics. This ensures that the main insulation repair component can penetrate through the water-blocking buffer layer to the insulation shielding layer, and then penetrate to the defect locations in the insulation shielding layer, cross-linked polyethylene layer, and conductor shielding layer through wetting, achieving the desired repair effect. Simultaneously, it avoids the need for stringent electric field conditions during repair, thus offering greater potential for practical applications.

[0029] In some embodiments of this example, the flowability modifying component is at least one or a combination of at least two of the following in any mass ratio: methyl silicone oil, ethyl silicone oil, dimethyldichlorosilane, dimethyldibutoxysilane, dipropylene glycol butyl ether, p-tert-butylcatechol, tert-butyl-p-hydroxyanisole, methyldimethoxyethylphenylsilane, and cyanomethyldimethoxysilane. The flowability modifying component is preferably a small-molecule silicone oil component to further improve the flow characteristics of the main insulation repair component and increase its penetration and diffusion efficiency.

[0030] In this embodiment, the buffer layer repair component is one or at least two of the following in any mass ratio: methyl hydroxyacrylate, ethyl hydroxyacrylate, aromatic or alicyclic epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate.

[0031] In this embodiment, the conductivity-improving components include carbon black particles with a particle size of 500 μm or less, carbon fibers, carbon nanotubes, graphene, metal particles, or alloy particles.

[0032] The aforementioned metal particles are preferably metals such as platinum, gold, silver, copper, aluminum, zinc, and magnesium with a particle size of 500 μm or less.

[0033] In this embodiment, the catalyst for main insulation repair is one or a combination of at least two of the following in any mass ratio: titanium isopropoxide, titanium isopropoxy, titanium ethanol, titanium isopropoxide, titanium n-butoxide, titanium methanol, tetraisopropyl titanate, potassium hydroxide, and hydrochloric acid; the catalyst for buffer layer repair is one or a combination of at least two of the following in any mass ratio: hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, tertiary amine promoters, imidazole, boronyl halide complexes, zinc organic acid salts, and methylnadic anhydride.

[0034] In this embodiment, the components of the above-mentioned repair solution are exemplified as follows: Example 1: The repair solution comprises the following components by weight: 35 parts of main insulation repair component, 25 parts of buffer layer repair component, 10 parts of flowability modification component, 8 parts of conductivity improvement component, 1 part of catalyst for main insulation repair, and 1 part of catalyst for buffer layer repair. The main insulation repair component consists of trimethylmethoxysilane, the flowability modification component is methyl silicone oil, the buffer layer repair component is methyl hydroxyacrylate, the conductivity improvement component includes carbon black particles with a particle size of 500μm and below, the catalyst for main insulation repair is titanium isopropoxide, and the catalyst for buffer layer repair is hexahydrophthalic anhydride.

[0035] Example 2: The repair solution comprises the following components by weight: 40 parts of main insulation repair component, 30 parts of buffer layer repair component, 15 parts of flowability modification component, 12 parts of conductivity improvement component, 3 parts of catalyst for main insulation repair, and 2 parts of catalyst for buffer layer repair. The main insulation repair component consists of trimethylmethoxysilane and methylphenyldimethoxysilane; the flowability modification component consists of methyl silicone oil and ethyl silicone oil (mass percentage 1:1); the buffer layer repair component consists of methyl hydroxyacrylate and ethyl hydroxyacrylate (mass percentage 1:1); the conductivity improvement component includes platinum metal particles with a particle size of 500 μm and below; the catalyst for main insulation repair is titanium isopropoxide and titanium isopropoxy (mass percentage 1:1); and the catalyst for buffer layer repair is hexahydrophthalic anhydride and methylhexahydrophthalic anhydride (mass percentage 1:1).

[0036] Example 3: The repair solution comprises the following components by weight: The main insulation repair component consists of 37 parts, the buffer layer repair component consists of 28 parts, the flowability modification component consists of 13 parts, the conductivity improvement component consists of 10 parts, the main insulation repair catalyst consists of 2 parts, and the buffer layer repair catalyst consists of 1.5 parts. The main insulation repair component consists of trimethylmethoxysilane and methylphenyldimethoxysilane; the flowability modification component consists of methyl silicone oil, ethyl silicone oil, and p-tert-butylcatechol (mass percentage 1:1:1); the buffer layer repair component consists of methyl hydroxyacrylate, bisphenol A epoxy resin, and ethyl hydroxyacrylate (mass percentage 1:1:1); the conductivity improvement component includes alloy microparticles (Au-Cu alloy) with a particle size of 500 μm and below; the catalyst for main insulation repair consists of titanium isopropoxide, titanium ethanolate, and titanium isopropoxy (mass percentage 1:1:1); and the catalyst for buffer layer repair consists of hexahydrophthalic anhydride, imidazole, and methylhexahydrophthalic anhydride (mass percentage 1:1:1).

[0037] The repair solutions prepared in Examples 1-3 above were used for multi-effect repair of cables. A 110kV power cable that had been decommissioned due to an accident after 16 years of operation was selected. Three 1.5-meter sections of cable with intact insulation were cut. Following the repair steps described above, a hole was drilled in the middle for repair. Injection was carried out at a pressure of 0.15 MPa for 30 minutes, followed by a 120-hour settling period. The performance of the repaired cable was then tested, and the insulation resistance and dielectric loss of the three selected cable sections showed improvement. Further analysis of the diffusion of the main components of the repair solution in the main insulation of the repaired cable was conducted. The cable was cut approximately 0.5 meters from the injection hole, and infrared spectroscopy analysis revealed characteristic peaks of the siloxane component. Finally, a sample was taken from the buffer layer approximately 0.5 meters from the injection hole, and the conductivity of the buffer layer showed a significant improvement. Based on the previous embodiment, another embodiment of this application provides a method for preparing a repair liquid, which includes mixing a main insulation repair component, a buffer layer repair component, a flowability modification component, and a conductivity improvement component in proportion by weight to obtain a mixture one; According to the preset mixing time, the main insulation repair catalyst and the buffer layer repair catalyst are added sequentially in parts by weight to the mixture to obtain the repair solution.

[0038] In this embodiment, the conductivity-improving component can be added to the mixture after the main insulation repair component, buffer layer repair component, and flowability-modifying component are mixed. The above method has higher mixing efficiency.

[0039] In this application, the conductivity-improving component can be added to the mixture after the main insulation repair component, buffer layer repair component, and flowability-modifying component are mixed. The above method has a higher mixing efficiency.

[0040] In this embodiment, the above mixing method is achieved by a stirring device with a rotation speed of 60 rpm to 120 rpm.

[0041] In this embodiment, the mixing temperature of the above-mentioned mixture one is preferably room temperature, the mixing time is not less than 20 min, the mixing time after adding the above-mentioned main insulation repair catalyst is not less than 10 min, and the mixing time after adding the above-mentioned buffer layer repair catalyst is not less than 10 min. After mixing the catalyst, the mixture is allowed to stand for at least 30 min under room temperature and vacuum conditions to obtain the above-mentioned repair solution.

[0042] In this embodiment, the above-mentioned mixture 1 can be used for storage and long-distance transportation (land transport). It can be stored in a sealed environment for no more than 7 days. After transporting the above-mentioned mixture 1 to the repair site, the main insulation repair catalyst and the buffer layer repair catalyst can be added sequentially according to a preset time. The prepared repair solution can be stored for no more than 8 hours.

[0043] In this embodiment, adding the components and catalyst in the above order can effectively delay the curing reaction of the buffer layer repair component and avoid the situation where the main insulation layer is not repaired because the buffer layer repair component has already cured before the main insulation repair component has penetrated and diffused to the defect location. Please refer to Figure 4 and Figure 5 Based on the previous embodiment, another embodiment of this application provides a cable multi-effect combined injection repair device, which mainly includes a pressurizing device, a liquid storage device and an injection device connected in sequence. The liquid storage device is used to store repair liquid, and the pressurizing device can output a preset injection pressure to the liquid storage device. The injection end of the injection device is located on the side wall of the repair tank 7 away from the outer sheath. The repair fluid stored in the liquid storage device can be injected into the cable through the injection device at a preset injection pressure.

[0044] In this embodiment, the cable includes, from the inside out, a cable core 12, a main insulation layer 11, a water-blocking buffer layer 10, a metal sheath 9, and an outer sheath 8. The main insulation layer 11 includes, from the outside in (from the outer sheath to the cable core), an insulating shielding layer 111, a cross-linked polyethylene layer 112, and a conductor shielding layer 113.

[0045] In this embodiment, the injection device includes an injection nozzle 1. When injecting the repair fluid, the injection end of the injection nozzle 1 can be embedded in the water-blocking buffer layer 10 and can pass through the water-blocking buffer layer 10 at the bottom of the repair groove 7. It is located on the main insulation layer (i.e., on the side of the main insulation layer 11 close to the water-blocking buffer layer 10), specifically on the side of the insulating shield layer 111 close to the water-blocking buffer layer. The injection end of the injection nozzle 1 does not cause structural damage to the main insulation layer 11 (specifically the insulating shield layer 111).

[0046] In this embodiment, the liquid storage device is preferably a liquid storage tank 5. Similarly, a liquid storage tank with a pressure measuring component or a liquid storage tank with a flow rate control component can be selected according to actual application requirements.

[0047] In this embodiment, the pressurization device is preferably an air compressor 6, and the air compressor 6, the liquid storage tank 5, and the injection nozzle 1 are all connected by hoses.

[0048] In this embodiment, the air pressure output by the pressurizing device is preferably 0.15 MPa to 0.18 MPa.

[0049] In this embodiment, the above-mentioned device further includes a control valve 2, a flow meter 3, and a protection valve 4; the protection valve 4, the flow meter 3, and the control valve 2 are sequentially arranged on the connection link between the liquid storage device and the injection device, and the protection valve 4 is arranged on the connection link between the pressurizing device and the liquid storage device.

[0050] In this embodiment, the injection state of the repair fluid in the injection nozzle 1 can be controlled by setting the control valve 2, and the flow meter 3 can control the flow rate and velocity of the repair fluid.

[0051] In this embodiment, a pressure relief valve or a pressure regulating valve may be provided between the air compressor 6 and the liquid storage tank 5 to control the pressurization pressure in real time, and at the same time improve the safety performance of the device.

[0052] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of this application.

Claims

1. A multi-effect combined injection-type repair method for cables, used to repair cables, wherein the cable comprises, from the inside out, a cable core, a main insulation layer, a water-blocking buffer layer, a metal sheath, and an outer sheath, characterized in that, include: A repair groove is provided in a specific section of the cable. Both the water-blocking buffer layer and the main insulation layer at the location of the specific section are defective. The repair groove passes through the outer sheath and the metal sheath in sequence. The groove sidewall away from the outer sheath is located on the side of the water-blocking buffer layer close to the metal sheath. Repair fluid is injected into the cable through the repair groove under pressure. The repair fluid has conductive, targeted induction and penetrating properties. The repair fluid contains a main insulation repair component and a buffer layer repair component. The main insulation repair component and the buffer layer repair component are mutually stable under given conditions. After sealing the repair groove, when the cable is put back into use and powered on, the repair liquid permeates and diffuses through the water-blocking buffer layer and then wets the main insulation layer, thus simultaneously repairing the defects in the water-blocking buffer layer and the main insulation layer.

2. The cable multi-effect combined injection repair method according to claim 1, characterized in that, The repair groove is located on the sidewall away from the outer sheath at a depth of 1 / 3 to 1 / 2 of the depth of the water-blocking buffer layer from the outer sheath toward the cable core.

3. The cable multi-effect combined injection repair method according to claim 1, characterized in that, The pressurization pressure is 0.15 MPa to 0.18 MPa, and the injection time of the repair fluid is 20 min to 30 min.

4. A repair fluid for use in the multi-effect combined injection repair method for cables according to any one of claims 1-3, characterized in that, The following components are included by weight: The main insulation repair component comprises 35 to 40 parts, the buffer layer repair component comprises 25 to 30 parts, the flowability modification component comprises 10 to 15 parts, the conductivity improvement component comprises 8 to 12 parts, the main insulation repair catalyst comprises 1 to 3 parts, and the buffer layer repair catalyst comprises 1 to 2 parts; the main insulation repair component has targeted induction characteristics and penetration characteristics.

5. The repair solution according to claim 4, characterized in that, The main insulation repair component is composed of trimethylmethoxysilane, or of trimethylmethoxysilane and methylphenyldimethoxysilane, wherein the mass percentage of trimethylmethoxysilane in the main insulation repair component is not less than 70%, and the mass percentage of trimethylmethoxysilane in the repair solution is not less than 30%.

6. The repair solution according to claim 5, characterized in that, The flowability-modifying component is one or at least two of the following in any mass ratio: methyl silicone oil, ethyl silicone oil, dimethyl dichlorosilane, dimethyl dibutoxysilane, dipropylene glycol butyl ether, p-tert-butylcatechol, tert-butyl-p-hydroxyanisole, methyl dimethoxyethylphenylsilane, and cyanomethyl dimethoxysilane.

7. The repair solution according to claim 4, characterized in that, The buffer layer repair component is one or at least two of the following in any mass ratio: methyl hydroxyacrylate, ethyl hydroxyacrylate, aromatic or alicyclic epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate.

8. The repair solution according to claim 7, characterized in that, The conductivity-enhancing components include carbon black particles with a particle size of 500 μm or less, carbon fibers, carbon nanotubes, graphene, metal microparticles, or alloy microparticles.

9. The repair solution according to claim 4, characterized in that, The catalyst for main insulation repair is one or a combination of at least two of the following in any mass ratio: titanium isopropoxide, titanium isopropoxy, titanium ethanol, titanium isopropoxide, titanium n-butoxide, titanium methyl methoxide, tetraisopropyl titanate, potassium hydroxide, and hydrochloric acid; the catalyst for buffer layer repair is one or a combination of at least two of the following in any mass ratio: hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, tertiary amine promoters, imidazole, boronyl halide complexes, zinc organic acid salts, and methylnadic anhydride.

10. A method for preparing a repair solution as described in any one of claims 4-9, characterized in that, include: Mix the main insulation repair component, buffer layer repair component, flowability modification component, and conductivity improvement component according to the weight proportions to obtain mixture one; According to the preset mixing time, the main insulation repair catalyst and the buffer layer repair catalyst are added sequentially in parts by weight to the mixture to obtain the repair solution.

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