Buffer layer ablation prevention method based on electrochemical anticorrosive coating

Abstract

The invention discloses a buffer layer ablation prevention method based on an electrochemical anti-corrosion coating, and belongs to the field of high-voltage power cable processing, and the method comprises the following steps: wrapping a semi-conductive water-blocking buffer layer on an insulated wire core; spraying conductive anticorrosive paint on the inner surface of the corrugated aluminum sheath to form an electrochemical anticorrosive coating; coating the outer layer of the corrugated aluminum sheath on which the electrochemical anti-corrosion coating is formed with an anti-corrosion agent to obtain an anti-corrosion corrugated aluminum sheath; the high-voltage cable buffer layer is prevented from being ablated based on the semi-conductive water-blocking buffer layer and the anti-corrosion corrugated aluminum sheath. According to the invention, the aluminum sheath and the buffer layer are effectively prevented from electrochemical corrosion, so that the occurrence of an ablation fault of the buffer layer of the high-voltage cable is effectively avoided, and serious loss caused by the ablation fault during operation of the cable can be effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of high-voltage power cable processing, and in particular relates to a method for preventing and controlling ablation of a buffer layer based on an electrochemical anti-corrosion coating. Background Art

[0002] The ablation defect of the buffer layer of high-voltage cables is a type of cable failure that has frequently occurred in recent years, causing huge losses to the power transmission system. The main manifestations of ablation defects are the appearance of a large amount of white powder in the cable aluminum sheath, buffer layer and insulation shielding layer, the presence of ablation holes in the buffer layer, and the corrosion of the aluminum sheath. The water-blocking buffer layer is divided into a three-layer composite structure, with fluffy cotton and non-woven fabric on both sides, and a semi-conductive resistive water powder in the middle layer, which is obtained by impregnating a semi-conductive water-based glue with a highly absorbent resin sodium polyacrylate. A large number of studies on the ablation defect of the buffer layer have shown that the buffer layer of high-voltage cables will be locally damp due to the damage of the outer sheath, and the water-blocking powder will absorb water. When the buffer layer is damp, electrochemical corrosion occurs, generating white powdery high-resistance substances such as Na2CO3, Na2HCO3 and Al2O3. After absorbing water, the water-blocking powder exhibits high resistance characteristics, and expands and precipitates between the buffer layer and the aluminum sheath and between the buffer layer and the insulation shield. The generated high-resistance substances and water-blocking powder will cause the local resistance of the buffer layer to increase significantly, which will lead to excessive local partial pressure of the buffer layer, causing local heat concentration. The heat causes the buffer layer fluffy cotton and the conductive fiber network of the non-woven fabric to overheat and melt, continuously damaging the buffer layer and even the outer insulation shield, causing pits or bulges, etc. After a long period of accumulation, it eventually extends to the main insulation, causing irreversible damage to the main insulation, and further leading to the breakdown failure of the main insulation. It can be seen that the buffer layer ablation defect seriously endangers the safe and stable operation of high-voltage cable lines.

[0003] The buffer layer ablation defect of high-voltage cables is a latent defect of cables. At present, the only way to eliminate the hidden danger of water-blocking buffer layer ablation defect is to replace the entire cable line by power outage. This method is time-consuming and costly. At present, the stock of high-voltage cables with water-blocking buffer layer structure is large, so a method that can prevent buffer layer ablation failure is urgently needed. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a method for preventing and controlling ablation of a buffer layer based on an electrochemical anti-corrosion coating to solve the problems existing in the above prior art.

[0005] To achieve the above object, the present invention provides a method for preventing and controlling ablation of a buffer layer based on an electrochemical anti-corrosion coating, comprising:

[0006] The insulated wire core is wrapped with a semi-conductive water buffer layer;

[0007] Spraying a conductive anti-corrosion coating on the inner surface of the corrugated aluminum sheath to form an electrochemical anti-corrosion coating;

[0008] The outer layer of the corrugated aluminum sheath formed with the electrochemical anti-corrosion coating is coated with an anti-corrosion agent to obtain an anti-corrosion corrugated aluminum sheath;

[0009] The semi-conductive water-resistant buffer layer and the anti-corrosion corrugated aluminum sheath are used to prevent and control the ablation of the buffer layer of the high-voltage cable.

[0010] Optionally, the components of the electrochemical anti-corrosion coating include, by weight: 0 to 15 parts of conductive material; 0 to 10 parts of aniline; 0 to 10 parts of eucommia gum; 0 to 20 parts of additives; 0 to 30 parts of mica powder; 0 to 50 parts of epoxy resin; 0 to 50 parts of solvent; and 0 to 15 parts of film-forming resin.

[0011] Optionally, the graphene is thin-layer graphene, and the sheet diameter of the thin-layer graphene is 1-10 μm and the thickness is 2-3 nm.

[0012] Optionally, the auxiliary agent includes a dispersant and a curing agent.

[0013] Optionally, the dispersant is polyacrylate or sodium dodecylbenzene sulfonate;

[0014] The curing agent is isocyanate or silane.

[0015] Optionally, the solvent is toluene or xylene or a mixture of toluene and xylene.

[0016] Optionally, the film-forming resin is nitrocellulose or polystyrene or polyvinyl chloride or a mixture of nitrocellulose, polystyrene and polyvinyl chloride.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects:

[0018] The present invention provides a method for preventing and controlling ablation of an electrochemical anti-corrosion coating buffer layer, which effectively solves the problem of ablation of a high-voltage cable buffer layer. By wrapping the insulating core with a semi-conductive water-resistant buffer layer, the insulation and waterproof properties of the cable are enhanced. Spraying a conductive anti-corrosion coating to form an electrochemical anti-corrosion coating improves the anti-corrosion ability of the cable. The outer layer is coated with an anti-corrosion agent to further enhance the anti-corrosion effect. The method significantly improves the service life and safety of high-voltage cables and reduces maintenance costs by comprehensively using electrochemical anti-corrosion and physical barrier means. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1 This is a specific flow chart of an embodiment of the present invention when used in cable production;

[0021] Figure 2 This is a schematic diagram of a simulated ablation experimental platform according to an embodiment of the present invention;

[0022] Figure 3 The morphology of each layer after the simulated ablation experiment of the embodiment of the present invention is shown, wherein Figure (a) shows the ablation morphology without spraying the conductive anti-corrosion coating, and Figure (b) shows the ablation morphology after spraying the conductive anti-corrosion coating. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0025] Embodiment 1

[0026] The present embodiment provides a conductive anti-corrosion coating, which includes, by weight: 5 parts of conductive carbon black, 10 parts of additives, 40 parts of epoxy resin, and 10 parts of film-forming resin.

[0027] The above components were weighed in proportion, placed in a vacuum degassing mixer and stirred for 8 minutes at a speed of 1000 r / min, and then vacuum degassed for 2 minutes to obtain the conductive anti-corrosion coating.

[0028] The conductive anti-corrosion coating prepared by this embodiment has low conductivity and anti-corrosion performance and poor coating effect.

[0029] Embodiment 2

[0030] The present embodiment provides a conductive anti-corrosion coating, which includes, by weight: 15 parts of graphite, 10 parts of additives, 40 parts of epoxy resin, 5 parts of aniline, and 10 parts of solvent.

[0031] The above components were weighed in proportion, placed in a vacuum degassing mixer and stirred for 20 minutes at a speed of 1000 r / min, and then vacuum degassed for 4 minutes to obtain the conductive anti-corrosion coating.

[0032] The conductive anti-corrosion coating prepared by this embodiment has good conductivity and anti-corrosion performance, but poor coating effect.

[0033] Embodiment 3

[0034] The present embodiment provides a conductive anti-corrosion coating, which includes, by weight, 10 parts of graphene, 15 parts of an additive, 40 parts of an epoxy resin, 20 parts of a film-forming resin, and 20 parts of a solvent.

[0035] The above components were weighed in proportion, placed in a vacuum degassing mixer and stirred for 25 minutes at a speed of 1000 r / min, and then vacuum degassed for 5 minutes to obtain the conductive anti-corrosion coating.

[0036] The conductive anti-corrosion coating prepared by this embodiment has good conductivity and anti-corrosion properties and a good coating effect.

[0037] Embodiment 4

[0038] The present embodiment provides a conductive anti-corrosion coating, which includes, by weight: 10 parts of carbon nanotubes, 5 parts of eucommia gum, 15 parts of additives, 40 parts of epoxy resin, and 20 parts of film-forming resin.

[0039] The above components were weighed in proportion, placed in a vacuum degassing mixer and stirred for 40 minutes at a speed of 1000 r / min, and then vacuum degassed for 5 minutes to obtain the conductive anti-corrosion coating.

[0040] The conductive anti-corrosion coating prepared by this embodiment has good conductivity and anti-corrosion performance, but poor coating effect.

[0041] Embodiment 5

[0042] The buffer layer ablation failure is caused by electrochemical corrosion between the buffer layer and the aluminum sheath after absorbing water, resulting in the accumulation of high-resistance powder, which leads to uneven current density. The uneven electrical contact leads to radial current concentration, which causes local temperature rise in the buffer layer at the current concentration point, and is more serious when it is damp. The thermal effect of the current causes the buffer layer to ablate, and the ablation extends to the aluminum sheath and the semi-conductive insulation shielding layer, and then further to the main insulation, eventually leading to an irreversible main insulation breakdown accident. Therefore, if the occurrence of electrochemical corrosion can be blocked before the ablation defect occurs, the hidden dangers of the water-blocking buffer layer ablation defect can be eliminated quickly, effectively and at a low cost. At present, there is no method to prevent the occurrence of buffer layer ablation based on the electrochemical corrosion mechanism of the high-voltage cable buffer layer.

[0043] The present embodiment provides a method for preventing and controlling buffer layer ablation based on an electrochemical anti-corrosion coating, the method comprising the following steps: wrapping an insulating core with a semiconductor resistive water-repellent buffer layer; spraying a conductive anti-corrosion coating on the inner surface of a corrugated aluminum sheath to form an electrochemical anti-corrosion coating; coating the outer layer of the corrugated aluminum sheath with the electrochemical anti-corrosion coating with an anti-corrosion agent to obtain an anti-corrosion corrugated aluminum sheath; and preventing and controlling ablation of a high-voltage cable buffer layer based on the semiconductor resistive water-repellent buffer layer and the anti-corrosion corrugated aluminum sheath.

[0044] Step S1: wrapping the insulated wire core with a semi-conductive water buffer layer;

[0045] Step S2: The conductive anti-corrosion coating to be applied is passed through a transmission pipe and sprayed on the inner surface of the corrugated aluminum sheath to form an electrochemical anti-corrosion coating; wherein the components of the conductive anti-corrosion coating include, by weight: 0 to 15 parts of carbon black; 0 to 15 parts of graphite; 0 to 15 parts of carbon nanotubes; 0 to 15 parts of graphene; 0 to 20 parts of aniline; 0 to 10 parts of eucommia gum; 0 to 5 parts of additives; 0 to 30 parts of mica powder; 0 to 50 parts of epoxy resin; 0 to 30 parts of solvent; and 0 to 5 parts of film-forming resin.

[0046] The conductive material is one or more of carbon black, thin-layer graphene, carbon nanotubes or graphite, and the graphene is thin-layer graphene with a sheet diameter of 1-10 μm and a thickness of 2-3 nm;

[0047] The auxiliary agent includes a dispersant and a curing agent; the dispersant includes polyacrylate or sodium dodecylbenzene sulfonate; the curing agent includes isocyanate or silane;

[0048] The solvent is specifically toluene, xylene or a mixture thereof;

[0049] The film-forming resin is specifically one of nitrocellulose, polystyrene, polyvinyl chloride or a mixture thereof;

[0050] Step S3: welding the corrugated aluminum sheath, and coating the outer surface of the corrugated aluminum sheath with an anti-corrosion layer: asphalt;

[0051] Step S4: Install the outer sheath and inspect the cable before leaving the factory.

[0052] As a specific implementation of this embodiment, the conductive anti-corrosion coating in Example 3 is selected in this embodiment. The conductive anti-corrosion coating has good conductivity, anti-corrosion and performance, and has a good coating effect; the conductive anti-corrosion coating is evenly sprayed on the inner surface of the corrugated aluminum sheath through the transmission tube; after the insulating core is wrapped with a semi-conductive water-repellent buffer layer, it is welded to the corrugated aluminum sheath after the inner surface is processed, and the outer layer of the corrugated aluminum sheath is coated with an anti-corrosion layer (asphalt), and the outer sheath is installed and inspected before leaving the factory. The specific process is as follows Figure 1 shown.

[0053] The method for preventing buffer layer ablation disclosed in the present invention improves the cable structure during cable manufacturing and sprays a conductive anti-corrosion coating inside the corrugated aluminum sheath. Among them, the conductive anti-corrosion coating used is graphene through physical corrosion protection and electrochemical corrosion protection. Physical corrosion protection: The physical corrosion protection mechanism of graphene lies in its impermeability and good chemical inertness to all atoms and molecules, and its hydrophobicity, which can increase the contact angle of the coating, thus playing a good physical shielding corrosion role; Electrochemical corrosion protection: The electrochemical corrosion protection mechanism of graphene lies in its excellent electrical conductivity. When the metal substrate is in contact, its self-corrosion potential is high, which can delay electrochemical corrosion. When using this method, the cable anti-corrosion spraying technology is mature and easy to operate. The conductive anti-corrosion coating used has excellent performance in all aspects. This method can effectively prevent the electrochemical corrosion of the aluminum sheath and the buffer layer, thereby effectively avoiding the occurrence of ablation failure of the high-voltage cable buffer layer, and can effectively avoid the serious losses caused by ablation failure during cable operation.

[0054] Embodiment 6

[0055] In this embodiment, a platform is built to simulate the ablation condition in the cable, and a simulated ablation scheme is adopted. Figure 2 As shown, specifically: aluminum sheet-buffer layer-shielding layer three-layer structure, size 2cm×2cm, applied 200g weight, constant current source 200mA, buffer layer injected 1ml deionized water, ablation 20min. Among them, the control group aluminum sheet is not sprayed with conductive anti-corrosion coating, and the experimental group is sprayed with conductive anti-corrosion coating in Example 3.

[0056] The morphology of the three layers in the two groups after ablation is as follows Figure 3 As shown. Figure (a) is the control group, where the conductive anti-corrosion coating was not sprayed. A large number of corrosion marks and pits can be observed on the surface of the aluminum sheet, a large amount of white products are attached to the buffer layer, the shielding layer is burned, and the electrochemical corrosion leads to obvious ablation. Figure (b) is the experimental group, where the coating on the surface of the aluminum sheet adheres well, no electrochemical corrosion marks are observed, no white powder with significant ablation characteristics is observed on the buffer layer, and the shielding layer is not burned. After spraying the conductive anti-corrosion coating, the occurrence of electrochemical corrosion of the aluminum sheet is effectively prevented.

[0057] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preventing and controlling ablation of a buffer layer based on an electrochemical anti-corrosion coating, characterized in that: The following steps are involved: The insulated wire core is wrapped with a semi-conductive water buffer layer; Spraying a conductive anti-corrosion coating on the inner surface of the corrugated aluminum sheath to form an electrochemical anti-corrosion coating; The outer layer of the corrugated aluminum sheath formed with the electrochemical anti-corrosion coating is coated with an anti-corrosion agent to obtain an anti-corrosion corrugated aluminum sheath; The semi-conductive water-resistant buffer layer and the anti-corrosion corrugated aluminum sheath are used to prevent and control the ablation of the buffer layer of the high-voltage cable.

2. The method according to claim 1, characterized in that The components of the electrochemical anti-corrosion coating include, by weight: 0 to 15 parts of carbon black; 0 to 15 parts of graphite; 0 to 15 parts of carbon nanotubes; 0 to 15 parts of graphene; 0 to 20 parts of aniline; 0 to 10 parts of eucommia gum; 0 to 5 parts of additives; 0 to 30 parts of mica powder; 0 to 50 parts of epoxy resin; 0 to 30 parts of solvent; and 0 to 5 parts of film-forming resin.

3. The method according to claim 2, characterized in that The graphene is a thin-layer graphene, and the sheet diameter of the thin-layer graphene is 1-10 μm and the thickness is 2-3 nm.

4. The method according to claim 2, characterized in that: The auxiliary agent includes a dispersant and a curing agent.

5. The method according to claim 4, characterized in that The dispersant is polyacrylate or sodium dodecylbenzene sulfonate; The curing agent is isocyanate or silane.

6. The method according to claim 2, characterized in that The solvent is toluene or xylene or a mixture of toluene and xylene.

7. The method according to claim 2, characterized in that The film-forming resin is nitrocellulose or polystyrene or polyvinyl chloride or a mixture of nitrocellulose, polystyrene and polyvinyl chloride.

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