High-voltage insulated cable buffer layer structure optimization method

Abstract

The invention discloses a structure optimization method for a buffer layer of a high-voltage insulated cable. The method comprises the following steps: (1) improving the conductivity of the buffer layer of the cable: reducing the surface resistance and volume resistivity of a strip; strictly stipulating the surface resistance deviation of the front and back surfaces and the length direction of the strip; the strip thickness deviation is strictly required; selecting a proper elastic strip; the uniformity of the water-blocking powder and the conductive carbon black in the strip is strictly controlled; (2) optimizing structural parameters of a cable buffer layer, wherein the thickness of the buffer layer is preferably reduced; the gap between the buffer layer and the metal protection layer is effectively controlled or thinned until tight contact; considering the influence of the gravity of the cable, reducing the embossing depth as much as possible, reducing the internal air gap and ensuring the compact structure of the cable; according to the invention, the buffer layer structure of the high-voltage cable can be optimized, the anti-overheating and anti-ablation capabilities of the cable are improved, the ablation probability of the buffer layer is reduced, the occurrence probability of line outage caused by ablation of the buffer layer of the cable is reduced, the operation reliability of the line is improved, and the power supply reliability of a power grid is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of high-voltage cable products, and in particular relates to a method for optimizing the buffer layer structure of a high-voltage insulating cable. Background Art

[0002] High-voltage power cable is an important primary power transmission equipment in the power grid. It plays an important role in the safe and stable operation of power loads. It has the characteristics of small line path width, easy line path selection, concealed burial, not easily affected by the surrounding environment and pollution, and high power transmission reliability.

[0003] In recent years, there have been reports of XPLE (Cross-Linked Polyethyelne) cable buffer layer ablation failures at voltage levels of 110kV and above. According to statistics, between 2010 and 2019, there were 11 cable failures at voltage levels of 110kV and above in Beijing, of which 6 were caused by cable buffer layer ablation, accounting for as high as 54.5%, seriously endangering the safe operation of the cable system. After dissecting the faulty cable, it was found that the cable insulation shielding layer had burn marks and continuous and regular white spots were attached to the buffer layer in many places. These ablation marks were located at the trough of the aluminum sheath at the bottom of the cable. When the buffer layer ablation defect is serious, it will ablate the insulation shielding layer, eventually leading to the breakdown of the body, causing line tripping and power outages, resulting in economic losses.

[0004] like Figure 2 As shown in the figure, most of the high-voltage XLPE cables currently used in China adopt a corrugated (corrugated) aluminum sheath structure, and a semi-conductive buffer water-blocking layer 50 is added between the metal corrugated aluminum sheath 60 and the XLPE insulation 40 layer. The water-blocking buffer layer is composed of semi-conductive non-woven fabric and semi-conductive fluffy cotton, with a layer of water-blocking powder in the middle; if the electrical contact between the buffer layer and the aluminum sheath needs to be enhanced, copper wire braided cloth (commonly known as gold cloth) is wrapped around the buffer layer. The buffer layer can absorb the radial thermal expansion of the insulation, provide longitudinal water blocking, heat insulation and other protective functions, and provide a good electrical contact interface for the insulation shield and the metal sheath.

[0005] During normal operation, the cable buffer layer will gradually burn, develop defects and damage under the influence of heat, electricity, mechanics and other factors. Severe damage will lead to failure. Research has found that the formation mechanism of cable buffer layer ablation defects is: when the cable buffer layer produces white spots due to moisture or the gap between the buffer layer and the aluminum sheath is too large, the electrical contact between the buffer layer and the aluminum sheath is poor, and the electric field there will be distorted. When the field strength is greater than the breakdown voltage of the air, it will cause local discharge, leading to buffer layer ablation. As the discharge continues, it will continue to ablate the insulating shielding layer, eventually causing the cable body to break down. In view of the above defect formation mechanism, it is necessary to develop a high-voltage insulated cable buffer layer structure optimization method. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a method for optimizing the buffer layer structure of a high-voltage insulated cable, which can optimize the buffer layer structure of the high-voltage cable, improve the cable's own anti-overheating and anti-ablation capabilities, reduce the probability of buffer layer ablation, reduce the probability of line shutdown caused by cable buffer layer ablation, improve line operation reliability, and improve power supply reliability of the power grid.

[0007] The object of the present invention is achieved by: a method for optimizing the buffer layer structure of a high-voltage insulated cable, comprising the following steps: S1, improve the conductivity of the cable buffer layer; S11, reducing the surface resistance and volume resistivity of the semi-conductive buffer water-blocking tape; S12, strictly stipulate the surface resistance deviation of the buffer water-blocking tape on both sides and in the length direction, otherwise there will be a potential difference in the buffer water-blocking tape itself; S13, strictly require the thickness deviation of buffer water blocking tape; S14, select a buffer water-blocking tape with appropriate elasticity to meet the insulation thermal expansion requirements and ensure good electrical contact; S15, strictly control the uniformity of water-blocking powder and conductive carbon black in the buffer water-blocking tape to ensure that the electrical performance of the buffer water-blocking tape is consistent along the length of the cable; S2, optimize the structural parameters of the cable buffer layer; S21, the thickness of the buffer layer should be reduced while ensuring that the XLPE insulation layer can expand under the condition of heat, thereby greatly reducing thermal resistance and increasing thermal conductivity; S22, effectively controlling the gap between the buffer layer and the metal sheath or thinning the gap until they are in close contact, will help improve the electric field distribution in the buffer layer and the metal sheath, and avoid the air gap from being subjected to a high electric field strength and causing local discharge with the metal sheath; S23, considering the influence of the cable's own gravity, the stress between the buffer layer and the aluminum sheath is studied. The deeper the spiral corrugation of the metal sheath is, the better it is. Combined with COMSOL simulation, the corrugation depth should be reduced as much as possible to reduce the internal air gap and ensure the compact structure of the cable while being able to withstand external mechanical effects.

[0008] Preferably, in step S11, reducing the surface resistance of the strip is achieved by optimizing the material formula and manufacturing process and selecting raw materials with better conductive properties, wherein optimizing the material formula may be increasing the content of conductive filler; reducing the volume resistivity is achieved by adjusting the microstructure of the material and increasing the number and connectivity of conductive channels, wherein adjusting the microstructure of the material may adopt nanotechnology to improve the dispersion and interface bonding of the material.

[0009] Preferably, in step S12, strictly controlling the surface resistance deviation is achieved by ensuring the consistency and stability of the strip during the production process through strict quality control measures and process management, wherein the quality control measures can use high-precision testing equipment to perform multi-point testing on the surface resistance of the strip, and screen and adjust products that do not meet the requirements.

[0010] Preferably, in step S13, strict control of strip thickness deviation is achieved by adopting advanced production equipment and processes and strengthening quality control of raw materials, ensuring the thickness uniformity of the strip, ensuring the consistency of raw materials, and reducing thickness deviation caused by material changes, wherein the advanced production equipment and processes can be high-precision extrusion equipment and online detection systems.

[0011] Preferably, in step S14, selecting a suitable elastic strip is achieved by material selection and formulation optimization, adjusting the elastic modulus of the strip and strengthening the interface bonding between the strip and the insulation layer and the metal sheath, wherein the elastic modulus of the strip is adjusted by first conducting a mechanical property test and simulation analysis of the material, and then determining the optimal elastic parameters according to the actual operating conditions of the cable.

[0012] Preferably, in step S15, strict control of the uniformity of the additive is achieved by using advanced mixing equipment and processes and performing microstructure analysis and performance testing, while quality control is strengthened and sampling inspection is performed on each batch of products.

[0013] Preferably, in step S21, the thermal resistance is reduced by thinning the thickness of the buffer layer while ensuring that the XLPE insulation layer can expand when heated. Specifically, the minimum buffer layer thickness that meets the thermal expansion requirements of the insulation layer is determined through thermal analysis and simulation calculations, while the operating environment and load conditions of the cable are considered to optimize the design.

[0014] Preferably, in step S22, the close contact is achieved by optimizing the manufacturing process of the cable, and specifically, an extrusion molding or winding process can be used to tightly wrap the buffer layer between the insulating layer and the metal sheath.

[0015] Preferably, in step S23, reducing corrugation is achieved by optimizing corrugation process and parameters, and specifically, mechanical property testing and simulation analysis can be performed to determine the optimal corrugation depth and shape.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention are: The present invention improves the conductive properties of the cable buffer water-blocking tape, reduces the surface resistance and volume resistivity of the semi-conductive buffer water-blocking tape, selects a buffer water-blocking tape with suitable elasticity, and strictly controls the uniformity of the water-blocking powder and the conductive carbon black in the buffer water-blocking tape, so as to optimize the buffer layer structure of the high-voltage cable and enhance the overheating and ablation resistance of the cable itself; The present invention optimizes the structural parameters of the buffer layer and the aluminum sheath. The thickness of the buffer layer should be reduced while ensuring that the XLPE insulation layer can expand when heated. The gap (i.e., air gap) between the buffer layer and the metal sheath is effectively controlled or the gap is reduced until they are in close contact. Considering the influence of the gravity of the cable itself, the corrugation depth should be reduced as much as possible while being able to withstand external mechanical effects. By optimizing the design of the cable structure, the probability of buffer layer ablation is reduced, the probability of line shutdown caused by cable buffer layer ablation is reduced, the line operation reliability is improved, the power supply reliability of the power grid is improved, and significant social benefits are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structural optimization process of the present invention.

[0018] Figure 2 It is a schematic cross-sectional view of a high voltage XLPE cable in the prior art.

[0019] In the figure: 10, conductor 20, conductor shield 30, XLPE insulation layer 40, insulation shield 50, semi-conductive buffer water-blocking layer 60, corrugated aluminum sheath 70, outer sheath. DETAILED DESCRIPTION

[0020] It should be understood that the layer structure of an existing high-voltage XLPE cable (corrugated aluminum sheath structure) mainly includes the following parts from the inside to the outside: 1. Cable conductor: usually composed of multiple strands of copper or aluminum wires twisted together, it is the main path for current transmission and has good conductivity. 2. Conductor inner shielding layer: located outside the cable conductor, its function is to make the insulation layer and the cable conductor have better contact, eliminate the roughness of the conductor surface and the increase of the electric field strength on the conductor surface caused by the sharp points generated by the twisted wires of multiple strands of wires; generally made of semi-conductive materials, such as semi-conductive plastics, semi-conductive rubber, etc. 3. Inner insulation layer: It is the core insulation part of the cable and is made of cross-linked polyethylene (XLPE) material; XLPE has excellent electrical properties, heat resistance, aging resistance and mechanical properties, and can ensure the safe operation of the cable under high voltage. 4. Outer insulation layer (insulation shielding layer): outside the XLPE inner insulation layer, it is also made of semi-conductive material, mainly to make the insulation layer and the metal sheath have better contact and play the role of uniform electric field. 5. Buffer layer: located between the insulation shielding layer and the corrugated aluminum sheath. The buffer layer is usually made of a sponge-like strip of semi-conductive polyester non-woven fiber cloth; the water-blocking buffer layer is made of semi-conductive non-woven fabric and semi-conductive fluffy cotton, with a layer of water-blocking powder in the middle; its function is to absorb the radial thermal expansion of the insulation, provide longitudinal water-blocking, heat-insulating and other protective functions, and provide a good electrical contact interface for the insulation shield and the metal sheath. 6. Corrugated aluminum sheath: It is the metal protective layer of the cable, showing a wavy or wrinkled shape; this structure makes the sheath more flexible, can adapt to the bending deformation of the cable, and can resist external pressure, playing a role in mechanical protection; at the same time, the aluminum sheath, as a shielding layer, can effectively shield external electromagnetic interference and provide a grounding path for fault current. 7. Outer sheath: Generally made of materials such as polyvinyl chloride (PVC), it is mainly used to protect the various layers of the cable structure from the influence of the external environment, such as moisture, corrosion, mechanical damage, etc.

[0021] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0022] like Figure 1 As shown, the present invention provides a method for optimizing the buffer layer structure of a high-voltage insulated cable, comprising the following steps: S1, improve the conductivity of the cable buffer layer.

[0023] S11, reduce the surface resistance and volume resistivity of the semi-conductive buffer water-blocking tape.

[0024] The reduction of the surface resistance of the strip is achieved by optimizing the material formulation and manufacturing process and selecting raw materials with better conductive properties, wherein the optimization of the material formulation may be to increase the content of conductive fillers.

[0025] Specifically, reducing the surface resistance can reduce the accumulation of charge on the surface of the strip and improve the uniformity of conductivity. By optimizing the material formula and manufacturing process, selecting raw materials with better conductivity, such as increasing the content of conductive fillers or using new conductive materials, the surface resistance can be effectively reduced.

[0026] Among them, reducing the volume resistivity is achieved by adjusting the microstructure of the material and increasing the number and connectivity of the conductive channels. Adjusting the microstructure of the material can use nanotechnology to improve the dispersion and interface bonding of the material.

[0027] Specifically, reducing the volume resistivity can enhance the conductivity of the strip and make the current more evenly distributed. This can be achieved by adjusting the microstructure of the material and increasing the number and connectivity of the conductive channels. For example, nanotechnology can be used to improve the dispersion and interface bonding of the material and enhance the conductivity.

[0028] S12, strictly regulate the surface resistance deviation of the buffer water-blocking tape on both sides and in the length direction, otherwise there will be a potential difference in the buffer water-blocking tape itself.

[0029] Among them, strict control of surface resistance deviation is achieved through strict quality control measures and process management to ensure the consistency and stability of the strip during the production process. The quality control measures can use high-precision testing equipment to perform multi-point testing on the surface resistance of the strip, and screen and adjust products that do not meet the requirements.

[0030] Specifically, if there is a surface resistance deviation in the buffer water-blocking tape, it will cause a potential difference between different parts. This may cause local electric field concentration, increase the risk of discharge, and affect the safe operation of the cable. Through strict quality control measures, the consistency of the tape during the production process can be ensured. High-precision testing equipment can be used to perform multi-point testing on the surface resistance of the tape, and products that do not meet the requirements can be screened and adjusted. At the same time, the process management during the production process should be strengthened to improve production stability and reduce the occurrence of resistance deviation.

[0031] S13, strict requirements on the thickness deviation of buffer water-blocking tape.

[0032] Among them, strict control of strip thickness deviation is achieved by adopting advanced production equipment and processes and strengthening quality control of raw materials, ensuring the uniformity of strip thickness, ensuring the consistency of raw materials, and reducing thickness deviation caused by material changes. Advanced production equipment and processes can be high-precision extrusion equipment and online detection systems.

[0033] Specifically, thickness deviation will affect the electrical and mechanical properties of the strip. Uneven thickness may lead to uneven electric field distribution and increase the possibility of partial discharge. At the same time, thickness deviation will also affect the buffering effect and waterproof performance of the strip. Use advanced production equipment and processes to ensure the thickness uniformity of the strip. For example, use high-precision extrusion equipment and online detection systems to monitor the thickness of the strip in real time and make automatic adjustments. Strengthen the quality control of raw materials to ensure the consistency of materials and reduce thickness deviations caused by material changes.

[0034] S14, select a buffer water-blocking tape with appropriate elasticity to meet the insulation thermal expansion requirements and ensure good electrical contact.

[0035] The selection of suitable elastic strip is achieved by material selection and formulation optimization, adjusting the elastic modulus of the strip and strengthening the interface bonding between the strip and the insulation layer and the metal sheath. The adjustment of the elastic modulus of the strip is to first conduct mechanical property tests and simulation analysis of the material, and then determine the optimal elastic parameters according to the actual operating conditions of the cable.

[0036] Specifically, the buffer water-blocking tape needs to meet the insulation thermal expansion requirements and ensure good electrical contact. Appropriate elasticity can adapt to the thermal expansion and contraction of the insulation layer during cable operation to avoid damage due to excessive mechanical stress. The elastic modulus of the tape can be adjusted through material selection and formulation optimization. Mechanical property tests and simulation analysis of the material can be performed to determine the optimal elastic parameters based on the actual operating conditions of the cable. At the same time, the interface bonding between the tape and the insulation layer and the metal sheath is considered to ensure good electrical contact and mechanical connection.

[0037] S15, strictly control the uniformity of water-blocking powder and conductive carbon black in the buffer water-blocking tape to ensure that the electrical performance of the buffer water-blocking tape is consistent along the length of the cable; Among them, strict control of additive uniformity is achieved by using advanced mixing equipment and processes as well as conducting microstructure analysis and performance testing. At the same time, quality control is strengthened and sampling inspection is carried out on each batch of products.

[0038] Specifically, the uniform distribution of water-blocking powder and conductive carbon black is critical to the electrical performance of the strip. Uneven distribution may cause local resistance to increase or decrease, affecting the electric field distribution and conductive properties. During the production process, advanced mixing equipment and processes are used to ensure that the water-blocking powder and conductive carbon black are fully mixed and uniform. Microstructure analysis and performance testing can be performed to verify the uniformity of the material. Strengthen quality control and conduct sampling inspections on each batch of products to ensure compliance with requirements.

[0039] S2, optimize the structural parameters of the cable buffer layer.

[0040] S21. The thickness of the buffer layer should be reduced while ensuring that the XLPE insulation layer can expand when heated, thereby greatly reducing thermal resistance and increasing thermal conductivity.

[0041] Among them, reducing thermal resistance is achieved by thinning the thickness of the buffer layer while ensuring that the XLPE insulation layer can expand due to heat. Specifically, thermal analysis and simulation calculations are used to determine the minimum buffer layer thickness that meets the thermal expansion requirements of the insulation layer. At the same time, the operating environment and load conditions of the cable are considered to optimize the design.

[0042] Specifically, under the premise of ensuring that the XLPE insulation layer can expand when heated, reducing the thickness of the buffer layer can reduce thermal resistance and increase thermal conductivity. This helps to improve the heat dissipation performance of the cable, reduce the operating temperature of the cable, and extend the service life of the cable. Through thermal analysis and simulation calculations, the minimum buffer layer thickness that meets the thermal expansion requirements of the insulation layer is determined. At the same time, the operating environment and load conditions of the cable are considered and optimized. New thermal conductive materials can be used or the structure of the buffer layer can be improved to improve thermal conductivity.

[0043] S22, effectively controlling the gap between the buffer layer and the metal sheath or thinning the gap until it is in close contact will help improve the electric field distribution within the buffer layer and the metal sheath, and avoid the air gap being subjected to a high electric field strength and causing local discharge with the metal sheath.

[0044] Among them, the close contact is achieved by optimizing the manufacturing process of the cable. Specifically, an extrusion molding or winding process can be used to make the buffer layer tightly wrapped between the insulation layer and the metal sheath.

[0045] Specifically, reducing the gap between the buffer layer and the metal sheath can improve the electric field distribution and avoid local discharge caused by the air gap being subjected to a high electric field strength. The closely contacted buffer layer and metal sheath can provide better electrical connection and shielding effect. By optimizing the manufacturing process of the cable, the fit between the buffer layer and the metal sheath can be ensured. The extrusion molding or winding process can be used to tightly wrap the buffer layer between the insulating layer and the metal sheath. At the same time, the flexibility and fit of the buffer layer can be improved by selecting appropriate materials and structures.

[0046] S23, considering the influence of the cable's own gravity, the stress between the buffer layer and the aluminum sheath is studied. The deeper the spiral corrugation of the metal sheath is, the better it is. Combined with COMSOL simulation, the corrugation depth should be reduced as much as possible to reduce the internal air gap and ensure the compact structure of the cable while being able to withstand external mechanical effects.

[0047] Among them, reducing corrugation is achieved by optimizing corrugation processes and parameters. Specifically, mechanical property tests and simulation analyses can be performed to determine the optimal corrugation depth and shape.

[0048] Specifically, the gravity of the cable itself will generate stress between the buffer layer and the aluminum sheath. Excessive stress may cause deformation or damage to the cable structure, affecting the safe operation of the cable. Through mechanical analysis and simulation calculation, the stress distribution of the cable under different installation conditions is studied. Combined with tools such as COMSOL simulation, the structural design of the cable is optimized to reduce stress concentration. Appropriate support structures can be used or the cable laying method can be adjusted to reduce the impact of gravity on the cable.

[0049] Specifically, too deep spiral corrugation will increase the internal air gap, reduce the structural compactness of the cable, and may also affect the electric field distribution and partial discharge performance. Under the premise of being able to withstand external mechanical effects, the corrugation depth can be reduced by optimizing the corrugation process and parameters. Mechanical performance tests and simulation analysis can be performed to determine the optimal corrugation depth and shape. At the same time, considering the installation and use environment of the cable, select the appropriate metal sheath material and thickness to improve the mechanical strength and protection performance of the cable.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for optimizing the buffer layer structure of a high-voltage insulated cable, characterized in that: The steps include: S1, improve the conductivity of the cable buffer layer; S11, reducing the surface resistance and volume resistivity of the semi-conductive buffer water-blocking tape; S12, strictly stipulate the surface resistance deviation of the buffer water-blocking tape on both sides and in the length direction, otherwise there will be a potential difference in the buffer water-blocking tape itself; S13, strictly require the thickness deviation of buffer water blocking tape; S14, select a buffer water-blocking tape with appropriate elasticity to meet the insulation thermal expansion requirements and ensure good electrical contact; S15, strictly control the uniformity of water-blocking powder and conductive carbon black in the buffer water-blocking tape to ensure that the electrical performance of the buffer water-blocking tape is consistent along the length of the cable; S2, optimize the structural parameters of the cable buffer layer; S21, the thickness of the buffer layer should be reduced while ensuring that the XLPE insulation layer can expand under the condition of heat, thereby greatly reducing thermal resistance and increasing thermal conductivity; S22, effectively controlling the gap between the buffer layer and the metal sheath or thinning the gap until they are in close contact, will help improve the electric field distribution in the buffer layer and the metal sheath, and avoid the air gap from being subjected to a high electric field strength and causing local discharge with the metal sheath; S23, considering the influence of the cable's own gravity, the stress between the buffer layer and the aluminum sheath is studied. The deeper the spiral corrugation of the metal sheath is, the better it is. Combined with COMSOL simulation, the corrugation depth should be reduced as much as possible to reduce the internal air gap and ensure the compact structure of the cable while being able to withstand external mechanical effects.

2. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In the step S11, the surface resistance of the strip is reduced by optimizing the material formula and the manufacturing process and selecting raw materials with better conductive properties, wherein the optimization of the material formula may be to increase the content of the conductive filler; the volume resistivity is reduced by adjusting the microstructure of the material and increasing the number and connectivity of the conductive channels, wherein the adjustment of the material microstructure may adopt nanotechnology to improve the dispersion and interface bonding of the material.

3. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In step S12, strictly controlling the surface resistance deviation is achieved by ensuring the consistency and stability of the strip during the production process through strict quality control measures and process management, wherein the quality control measures can use high-precision testing equipment to perform multi-point testing on the surface resistance of the strip, and screen and adjust products that do not meet the requirements.

4. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In step S13, strict control of strip thickness deviation is achieved by adopting advanced production equipment and processes and strengthening quality control of raw materials, ensuring the thickness uniformity of the strip, ensuring the consistency of raw materials, and reducing thickness deviation caused by material changes. The advanced production equipment and processes can be high-precision extrusion equipment and online detection systems.

5. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In step S14, selecting a suitable elastic strip is achieved by material selection and formulation optimization, adjusting the elastic modulus of the strip, and strengthening the interface bonding between the strip and the insulating layer and the metal sheath, wherein the elastic modulus of the strip is adjusted by first conducting a mechanical property test and simulation analysis of the material, and then determining the optimal elastic parameters according to the actual operating conditions of the cable.

6. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In step S15, strict control of the uniformity of the additives is achieved by using advanced mixing equipment and processes and performing microstructure analysis and performance testing. At the same time, quality control is strengthened and sampling inspection is performed on each batch of products.

7. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In step S21, the thermal resistance is reduced by thinning the thickness of the buffer layer while ensuring that the XLPE insulation layer can expand when heated. Specifically, the minimum buffer layer thickness that meets the thermal expansion requirements of the insulation layer is determined through thermal analysis and simulation calculations, while the operating environment and load conditions of the cable are considered to optimize the design.

8. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In step S22, the close contact is achieved by optimizing the manufacturing process of the cable, and specifically, an extrusion molding or winding process can be used to tightly wrap the buffer layer between the insulating layer and the metal sheath.

9. The method for optimizing the buffer layer structure of a high-voltage insulated cable according to claim 1, characterized in that: In step S23, the reduction of corrugation is achieved by optimizing the corrugation process and parameters. Specifically, mechanical property testing and simulation analysis can be performed to determine the optimal corrugation depth and shape.

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