A novel composite insulated aerospace cable, its manufacturing method and application

Abstract

This invention belongs to the field of aerospace power transmission technology, specifically relating to a novel composite insulated aerospace cable, its manufacturing method, and its application. The novel composite insulated aerospace cable includes a conductor core, an inner shielding layer, an insulation layer, a metal shielding braided layer, and an outer sheath. Both the inner shielding layer and the insulation layer are made of irradiated crosslinked modified ETFE material doped with 0.05% hydrophobic nano-silica, wherein the nano-silica has a purity >99% metals basis, a particle size of 15nm, and a specific surface area of ​​300±50m². 2 / g; the insulation layer thickness is 18mm; the conductor core adopts a two-stage concentric stranded structure, the inner shielding layer thickness is 0.8mm, the metal shielding braided layer adopts a silver-plated copper wire braided structure, and the outer sheath is made of radiation cross-linked modified ETFE material. This cable can stably carry 200kV voltage and 200A current, and its electrical and mechanical properties are stable in environments ranging from -183℃ to 230℃ and under strong radiation, making it suitable for high-voltage power transmission systems in spacecraft.

Description

Technical Field

[0001] This invention belongs to the field of aerospace power transmission technology, specifically relating to a novel composite insulated aerospace cable, its manufacturing method, and its application. Background Technology

[0002] As humanity's exploration of space accelerates, the power demands of space missions on energy systems are increasing daily. New-generation large spacecraft, such as space solar power stations, nuclear-powered satellites, deep space probes, and large electric propulsion spacecraft, have seen their transmission power leap from the traditional kilowatt level to the megawatt level. Taking a space solar power station as an example, its on-orbit solar array can have an area of ​​several thousand square meters or more, with a single solar panel output power ranging from hundreds of kilowatts to megawatts. Since solar arrays are typically deployed on large-scale structures outside the spacecraft, while the energy management system, propulsion system, and payload equipment are located inside the cabin, high-power electrical transmission requires long-distance cables. In traditional low-voltage transmission modes, Joule losses in the cables increase significantly with transmission distance. Continuing to use traditional hundreds of volts of transmission would require an extremely large transmission current, leading not only to a sharp increase in cable weight but also to serious heat buildup problems. Therefore, there is an urgent need to develop space cables capable of stable operation under high voltage (e.g., 200kV) and high current (e.g., 200A) conditions.

[0003] Currently, ETFE (ethylene-tetrafluoroethylene copolymer) has long held a core position in cable insulation materials due to its unique molecular structure and extremely high tear strength and abrasion resistance. However, the specifications of currently maturely applied aerospace cables are mostly limited to 28VDC, 115VAC, or 270VDC systems. This is because during spacecraft launch and on-orbit operation, the air pressure undergoes changes from atmospheric pressure to high vacuum. Once it enters the kilovolt range (kV), traditional ETFE insulation cannot effectively suppress partial discharge and surface flashover. In addition, the space environment also faces extreme conditions such as large temperature differences (-183℃ to 230℃), strong radiation (total dose > 50Mrad), and difficulties in vacuum heat dissipation. In low-pressure and vacuum environments, the mean free path of gas molecules increases, and the breakdown voltage drops sharply. In a vacuum, the lack of gas insulation results in a surface flashover voltage that is much lower than in an atmospheric environment. In a vacuum environment, convective heat dissipation fails, and the Joule heat generated by the large current can easily cause the temperature of the cable core to exceed the material limit. Long-term irradiation by high-energy particles can cause polymer materials to break down or cross-link and degrade, making the insulation brittle and cracked, ultimately leading to electrical failure.

[0004] To address the aforementioned technical bottlenecks, existing insulation design theories for ground-based high-voltage equipment do not fully consider the coupling effects of extreme aerospace environments such as vacuum, wide temperature variations, and intense radiation. Consequently, the technical system of low- and medium-voltage aerospace systems cannot be directly adapted to ultra-high-voltage scenarios. Therefore, there is an urgent need to develop a new type of composite insulated aerospace cable that can inherit the advantages of existing aerospace cable materials, such as lightweight and high-temperature resistance, while also overcoming voltage and current limits through material modification and structural innovation. This will allow it to adapt to extreme aerospace environments and drive the development of aerospace systems towards higher power and higher efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a novel composite insulated aerospace cable, its manufacturing method, and its applications. Through a multi-layer electric field-controlled structural design, the cable can stably carry 200kV DC or equivalent AC voltage. Under a continuous current carrying capacity of 200A, the temperature rise of the cable core is controllable, effectively avoiding the risk of thermal runaway. It significantly improves the surface flashover and breakdown thresholds under vacuum and low-pressure conditions, exhibits strong adaptability to vacuum environments, and maintains stable electrical and mechanical properties within a temperature range of -183℃ to 230℃. It can withstand cumulative high-energy particle radiation exceeding 50Mrad, extending its on-orbit service life. It is suitable for aerospace system integration, balancing lightweight design and flexibility, and is applicable to the power systems of next-generation high-power spacecraft.

[0006] The specific technical solution adopted by this invention is as follows: A novel composite insulated aerospace cable includes a conductor core, an inner shielding layer, an insulation layer, a metallic shielding layer, and an outer sheath. The inner shielding layer, insulating layer, and outer sheath are all made of modified ETFE (ethylene-tetrafluoroethylene copolymer) material and are cross-linked by radiation to achieve 200kV electric field homogenization and partial discharge suppression. The modified ETFE material is doped with 0.05% hydrophobic nano-silica (purity >99% metals basis, particle size 15nm, specific surface area 300±50m²). 2 / g); Combining a high-coverage metal braided shielding layer with a wear-resistant and radiation-resistant cross-linked modified ETFE outer sheath, this composite insulated aerospace cable possesses both electromagnetic shielding and heat dissipation capabilities. This allows it to maintain stable electrical and mechanical properties in environments ranging from -183℃ to 230℃ and under strong radiation, meeting requirements for 200A current carrying capacity, lightweight design, and high flexibility. It is suitable for highly reliable power transmission under complex wiring conditions in spacecraft.

[0007] The conductor core adopts a large-section, high-purity silver-plated copper stranded wire structure, preferably with multiple fine filaments concentrically stranded. A silver plating layer is applied to the outer side of each filament, which significantly reduces surface contact resistance and suppresses the high-frequency skin effect, while also improving the conductor's oxidation resistance under high temperature and radiation environments. The conductor cross-sectional area is preferably optimized based on a 200A continuous current carrying capacity requirement, ensuring current carrying capacity while also considering cable flexibility and weight control.

[0008] The inner shielding layer covers the outside of the conductor core wire. This inner shielding layer is made of irradiated cross-linked modified ETFE material, enabling uniform control of the electric field on the conductor surface. This layer effectively reduces electric field distortion on the conductor surface, suppresses local electric field concentration, and reduces partial discharge and vacuum surface flashover phenomena under ultra-high voltage conditions.

[0009] The insulating layer, which covers the outer surface of the inner shielding layer, is made of irradiated cross-linked modified ETFE. High-energy electron beam irradiation forms a stable three-dimensional cross-linked network between the ETFE molecular chains, significantly improving the material's thermal stability, creep resistance, and radiation resistance, while also enhancing its mechanical retention over a wide temperature range. The introduction of nano-silica filler into the insulating layer effectively suppresses space charge migration and reduces the probability of electron avalanche formation through the interfacial polarization and deep trapping effects of inorganic nanoparticles, thereby improving the partial discharge initiation voltage and breakdown strength in a vacuum environment. This insulating layer possesses high dielectric strength, low dielectric loss, and excellent radiation resistance, maintaining stable electrical and mechanical properties over a wide temperature range from -183℃ to 230℃. Its insulation thickness is graded according to a 200kV voltage level to ensure sufficient electrical safety margin.

[0010] The metal shielding braided layer covers the outside of the insulation layer. The metal shielding layer adopts a high coverage copper wire braided structure, which can serve as an electromagnetic shield and grounding channel to suppress external electromagnetic interference and leakage of internal electric field. It can also serve as a heat diffusion channel to a certain extent, which is beneficial to the radial conduction of heat generated by the conductor and insulation layer.

[0011] The outer sheath covers the outside of the metal shielding braided layer. The outer sheath is made of irradiated cross-linked modified ETFE material, which is wear-resistant and radiation-resistant. Its resistance to atomic oxygen erosion, micrometeorite impact, and mechanical wear is improved through formula optimization. The outer sheath also has a high surface emissivity, which is beneficial for improving the overall heat dissipation capacity of the cable through thermal radiation in a vacuum environment.

[0012] A method for manufacturing a novel composite insulated aerospace cable includes the following steps: S1. Preparation of conductor core wire: The oxygen-free copper rod is drawn in multiple passes, annealed, and then electroplated with a silver layer. The conductor core wire is then formed by multiple strands concentrically twisted together. S2. Extrusion of inner shielding layer: ETFE material doped with hydrophobic nano-silica is extruded and coated on the outside of the conductor core wire to form an inner shielding layer; S3. Molding the insulating layer and irradiating crosslinking: ETFE material doped with hydrophobic nano-silica is extruded and coated on the outside of the inner shielding layer. After cooling and shaping, it is crosslinked by electron beam irradiation. S4. Braided metal shielding layer: Silver-plated copper wire is braided on the outside of the insulation layer; S5. Extruded outer sheath: Irradiated cross-linked modified ETFE material is extruded and coated on the outside of the metal shielding braided layer.

[0013] An application of a novel composite insulated aerospace cable, which is used in the high-voltage power transmission system of spacecraft. The voltage level of the spacecraft's high-voltage power transmission system is 200kV, and the current carrying capacity is 200A. The spacecraft is a space-based solar power station.

[0014] The technical effects achieved by this invention are as follows: This invention discloses a novel composite insulated aerospace cable. Through a multi-layer electric field regulation structure design, the cable can stably carry 200kV DC or equivalent AC voltage. Under a continuous current carrying condition of 200A, the temperature rise of the cable core is controllable, effectively avoiding the risk of thermal runaway. It significantly improves the surface flashover and breakdown threshold under vacuum and low pressure conditions, exhibits strong adaptability to vacuum environments, and maintains stable electrical and mechanical properties within the range of -183℃ to 230℃. It can withstand high-energy particle radiation exceeding 50Mrad cumulatively, extending its on-orbit service life. It is suitable for aerospace system integration: balancing lightweight and flexibility, it is applicable to the power systems of next-generation high-power spacecraft. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention; Figure 3 This is a flowchart of the manufacturing method of the present invention; Figure 4 This is a side view flowchart of the present invention; Figure 5 This is a display diagram of the magnetic flux density modulus distribution of the aerospace cable of the present invention; Figure 6 This is a potential distribution diagram of the aerospace cable of the present invention; Figure 7 This is a diagram showing the electric field mode distribution of the aerospace cable of the present invention; Figure 8 This is a temperature distribution display diagram of the aerospace cable of the present invention.

[0016] The attached diagram lists the components represented by each number as follows: 1. Conductor core wire; 2. Inner shielding layer; 3. Insulation layer; 4. Metallic shielding layer; 5. Outer sheath. Detailed Implementation

[0017] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0018] Example 1: like Figures 1-2 As shown in Table 1, a novel composite insulated aerospace cable includes a conductor core 1, an inner shielding layer 2, an insulation layer 3, a metal shielding layer 4, and an outer sheath 5. The structural dimensions of the aerospace cable are shown in Table 1.

[0019] The conductor core 1 employs a high-purity oxygen-free copper silver-plated multi-strand fine filament structure to enhance conductivity and high-frequency transmission stability. A uniform silver layer of 2–3 μm thickness is plated onto the surface of each filament to reduce the skin effect and improve oxidation resistance. The conductor core 1 adopts a two-stage concentric stranding structure: the first layer is a sub-bundle structure, consisting of 19 filaments concentrically stranded in a 1+6+12 configuration to form a single-strand bundle; the second layer is a total stranding structure, further stranding more than 70 sub-bundles in a concentric layered manner to form the overall conductor. The nominal outer diameter of the conductor is 11.735 mm, with an allowable deviation range controlled between 11.176 and 12.065 mm to ensure structural consistency and electrical performance stability.

[0020] The inner shielding layer 2 is made of 0.05% hydrophobic nano-silica (purity >99% metal basis, particle size 15nm, specific surface area 300±50m²). 2 Radiation-crosslinked modified ETFE material ( / g) is used to achieve electric field homogenization and interface charge regulation by introducing silica. Based on GB / T31489.2-2020 and GJB 773B-2015, the thickness of the semiconductive shielding layer is designed to be 0.8mm, which not only meets the current carrying requirements of high-voltage, high-current cables, but also considers the lightweight requirements of aviation cables. At the same time, it can effectively cover the surface undulation structure formed by conductor stranding, eliminate local electric field distortion, thereby improving the overall electric field distribution uniformity and suppressing the risk of partial discharge.

[0021] The insulating layer 3 uses irradiated crosslinked modified ETFE as the insulating layer 3 and sheath material, and the thickness of the insulating layer 3 is 18mm. When designing the insulation structure, we considered that pure ETFE material is prone to macromolecular chain breakage and degradation under long-term high temperature and strong radiation environments. By introducing a multifunctional crosslinking agent and performing crosslinking modification, ETFE acquires excellent high-temperature mechanical elasticity and wear resistance, ensuring high flexibility under 200A high-current heating conditions. In addition, by uniformly dispersing nano-silica particles into the ETFE matrix through a melt blending process, the trapping effect of the organic-inorganic interface is utilized to effectively reduce the mean free path of high-energy electrons in the vacuum, significantly improving the macroscopic dielectric strength of the insulation system. Furthermore, the overall ETFE material is radiation-crosslinked modified, thereby significantly improving the material's thermal stability and anti-aging properties.

[0022] After pure ETFE is doped with nano-silica, the nanoparticles can achieve relatively uniform dispersion in the polymer matrix under low doping concentration conditions. Their huge specific surface area introduces a large number of deep traps in the interface region, which can effectively capture and bind charge carriers and suppress the accumulation and migration of space charge. At the same time, the uniformly distributed nanoparticles act as a microscopic barrier, which can enhance the scattering of high-energy electrons and restrict the movement of polymer molecular chain segments, thereby improving the material's resistance to electrical tree development and electrical breakdown, ultimately resulting in a significant increase in breakdown field strength.

[0023] However, when the doping concentration of nanoparticles exceeds a critical threshold, their high surface energy leads to agglomeration, resulting in decreased interfacial structural uniformity. On one hand, micropores and interfacial debonding easily form in and around the agglomerated regions, providing favorable conditions for partial discharge and electric field concentration. On the other hand, excessively dense interfacial traps overlap and gradually connect, transforming the trap network, originally designed for charge trapping, into carrier migration channels, thereby promoting charge transport. Furthermore, the significant difference in dielectric constant between the agglomerates and the matrix further causes local electric field distortion, enhancing the electric field concentration effect. These factors combined make it easier for breakdown initiation points to form within the material, ultimately leading to a significant decrease in the macroscopic breakdown field strength.

[0024] Experiments have verified that, under normal temperature and pressure, the breakdown electric field strength of pure ETFE is 119 kV / mm. However, after doping with 0.05% nano-silica, the breakdown electric field strength increases the most, reaching 127.4 kV / mm, an improvement of approximately 7.06%. Nano-silica can also improve the thermal conductivity of the material, alleviate the problem of local heat accumulation under high-power transmission conditions, and further improve the long-term operational reliability of the cable.

[0025] Experimental results show that the intrinsic breakdown field strength of the modified ETFE material at room temperature is 127.4 kV / mm. However, in actual aerospace applications, the material will be exposed to extreme environments such as vacuum and temperature fluctuations for extended periods, inevitably leading to a degradation in its insulation performance. To ensure design margin and reliability, it is necessary to derating the intrinsic breakdown field strength; therefore, the following relationship is introduced: (1) In the formula This is the corrected breakdown field strength obtained after considering environmental factors such as vacuum and high temperature. The breakdown field strength at room temperature and pressure. This is the melting temperature of the material (529.25K in the calculation). For ambient temperature, At atmospheric pressure (101.3 kPa), This refers to ambient air pressure.

[0026] The electric field distribution model of this aerospace cable is equivalent to a coaxial cylindrical electrode model. Under ultra-high voltage operating conditions, the electric field distribution inside insulation layer 3 is extremely non-uniform, with the maximum electric field intensity appearing on the outer surface of inner shielding layer 2. Its theoretical electric field formula is: (2) In the formula The voltage applied to the cable (to ensure absolute safety during long-term service, substitute the system power frequency withstand voltage and DC withstand test voltage of 250kV). The inner radius of insulation layer 3 is 6.6675 mm. This refers to the insulation thickness.

[0027] (3) Based on the calculation results of the above insulation design model, at a vacuum degree of 10... -4 Under extreme aerospace environmental conditions with a temperature range of -183℃ to 230℃, the theoretical minimum thickness of insulation layer 3 should not be less than 17.84mm. Considering factors such as manufacturing tolerances, material performance variability, and performance degradation at the end of the cable's life, the total insulation thickness was ultimately designed to be 18mm. This design ensures that the cable maintains stable insulation performance under long-term operation at 200kV and meets the requirements of the 250kV withstand voltage test, verifying its good insulation reliability and feasibility for engineering applications.

[0028] It can be further explained that this technical solution combines national standards, military standards, and gas discharge theory to comprehensively analyze key factors such as temperature, air pressure, vacuum degree, and electric field derating in the insulation structure design process. By combining relevant design equations, an insulation thickness calculation model under different temperature and air pressure conditions was established, and the insulation thickness optimization design and engineering design verification of the target high-voltage aerospace cable were completed.

[0029] The metal shielding layer 4 adopts a double-layer cross-woven structure of silver-plated copper wire, with a single wire diameter of 0.16 mm and a total thickness of approximately 1 mm. By optimizing the weaving process parameters, the shielding coverage rate reaches no less than 85%, while the weaving angle is controlled within the range of 50° to 72° to balance flexibility, mechanical strength, and electromagnetic shielding effectiveness, thereby achieving effective suppression of external electromagnetic interference and stable transmission of internal signals.

[0030] The outer sheath 5 is made of radiation-crosslinked modified ETFE material with a thickness of 1.5mm, which has excellent mechanical protection performance, radiation resistance, and environmental adaptability. At the same time, this structure also has a certain thermal management function, which can help dissipate heat from the cable under complex operating conditions, thereby improving the overall operational reliability and service life.

[0031] In summary, this embodiment improves the internal trap distribution and electric field uniformity of the material by introducing nano-silica filler into the ETFE matrix, effectively enhancing the breakdown field strength and insulation reliability of the insulating material under vacuum conditions, and providing a new technical route for the insulation design of aerospace high-voltage power transmission cables.

[0032] Example 2: like Figures 1-8 As shown, this embodiment discloses a method for manufacturing a novel composite insulated aerospace cable, including the following steps: Step S1, conductor core wire 1 preparation process: First, the oxygen-free copper rod is drawn in multiple passes to gradually reduce the wire diameter to about 0.25mm; then, it is annealed at about 450℃ in a continuous annealing furnace to restore the material's ductility and reduce internal stress; then, a uniform silver plating layer is formed on the surface of the copper wire through an electroplating process to improve the conductor's oxidation resistance and conductivity; finally, it is layered and formed by multi-strand concentric stranding equipment to form the flexible conductor core wire 1 structure.

[0033] Step S2, inner shielding layer 2 extrusion process: The inner shielding material is extruded and coated on the outer layer of the conductor core wire 1 using a single screw extruder, wherein the extrusion temperature is controlled at 250-300℃; the die head temperature is about 300℃; the extrusion speed is 10-20m / min; a uniform and continuous electric field control layer is formed through a stable extrusion process.

[0034] Step S3, Insulation Layer 3 Molding and Irradiation Crosslinking: Insulation Layer 3 is extruded using a plastic extruder, with the extrusion temperature controlled between 280 and 310°C, and then shaped using a cooling water bath. After molding, Insulation Layer 3 undergoes electron beam irradiation crosslinking treatment. The improved radiation resistance is mainly due to the high-energy electron beam bombardment of the ETFE macromolecular chain, which excites the generation of macromolecular free radicals and their recombination, transforming the original linear molecular structure into a dense three-dimensional network structure. This fundamentally locks the molecular chains and inhibits chain breakage and degradation under long-term high-energy particle bombardment in space.

[0035] Irradiation Process and Dosage Calculation: The cross-linking process utilizes a high-frequency, high-voltage electron accelerator. To reduce the risk of cable heating or even material degradation caused by a single large-dose, high-energy electron injection, a low-dose-rate, multi-scan irradiation method is employed. The irradiation dose is set by considering both the material's cross-linking degree requirements and the irradiation dose requirements of the aerospace environment. The specific irradiation dose calculation formula is derived as follows: According to the strict design specifications for long-term service and non-maintainable power systems in aerospace (refer to GJB 773B-2015 and GJB 1027A-2005), the design of aerospace cables must incorporate a radiation design margin.

[0036] (4) In the formula The maximum absorbed dose at the end of the cable's design life. The radiation dose to the space environment is 50 Mrad according to GJB 773B-2015. The safety margin factor is set to 2 according to GJB 1027A-2005.

[0037] When aerospace cables are cross-linked by a certain dose of electron beam irradiation, the density of cross-linking points formed inside the material is approximately proportional to the irradiation dose: (5) In the formula The initial crosslinking density during irradiation crosslinking. This is the cross-linking irradiation dose. is the radiation crosslinking efficiency constant of the material.

[0038] When space cables accumulate a certain dose of radiation in space, high-energy particles cause random breakage of the molecular backbone. The backbone breakage density is also directly proportional to the absorbed radiation dose in space. (6) In the formula This represents the molecular chain breakage density under space irradiation. denoted as the radiation chain-breaking efficiency constant of the material.

[0039] Whether aerospace cables will embrittle and fail at the end of their lifespan depends on the remaining effective cross-linking density within the material. When the fracture density caused by space radiation begins to offset the cross-linking density, the remaining effective cross-linking density is: (7) In the formula This represents the residual effective crosslinking density at the end of the product's lifespan.

[0040] To ensure that the insulating material retains the required mechanical properties at the end of its lifespan, its residual effective cross-linking density must be greater than 85%, thus providing the constraint conditions for radiation dose calculation: (8) According to the Charlesby-Pinner theory, the radiation resistance of fluoropolymers depends on their crosslinking-degradation ratio. Pure ETFE... While the potential value is limited, in systems incorporating nano-silica, the steric hindrance and deep trapping effect of the nano-inorganic interface significantly suppress the diffusion and chain-breaking reactions of free radicals. The value is significantly improved. Referring to research results on similar modified fluoropolymer systems, this type of system... The lifespan is typically distributed in the range of 30 to 50. For rigorous lifespan limit derivation, this model takes... The typical value is 40.

[0041] (9) In the formula The cross-linking-degradation ratio of the material.

[0042] By performing simultaneous analysis and derivation of the above model equations, a quantitative relationship between irradiation requirements and initial crosslinking dose can be established, thereby determining the minimum initial crosslinking irradiation dose required for insulating materials under different irradiation conditions.

[0043] (10) By introducing actual engineering parameters and combining them with the material irradiation crosslinking and radiation aging mechanisms for systematic derivation, the results show that when cables need to meet the lifespan requirement of a total radiation dose of 50 Mrad and the mechanical performance retention rate at the end of their lifespan is not less than 85%, the initial crosslinking irradiation dose of the modified ETFE insulation material should be greater than 166.67 kGy. This threshold is not only a necessary condition to ensure the long-term reliability of the material, but also provides an important design basis for the subsequent optimization of irradiation crosslinking process parameters.

[0044] Based on the irradiation damage mechanism, the evolution law of crosslinking degree, and the performance retention rate requirements at the end of the life, this technical solution theoretically derives the initial irradiation crosslinking dose of insulating materials, establishes a quantitative relationship between irradiation environment parameters and crosslinking dose, obtains a general calculation formula for irradiation crosslinking dose applicable to engineering design, and realizes the quantitative design of irradiation process parameters for insulating materials.

[0045] Step S4, Metal Shielding Braiding Process: Copper wire is braided on the outside of insulation layer 3 using high-speed braiding equipment, with a braiding angle of approximately 45°; coverage ≥90%; braiding tension is stably controlled.

[0046] Step S5, Extrusion and Post-processing of Outer Sheath 5: The outer sheath 5 is coated by extrusion equipment, with the extrusion temperature controlled at 260-300℃; the sheath thickness is controlled at about 1.5mm. After extrusion, heat setting treatment (150℃, 4 hours) is carried out to release residual stress and improve structural stability and flexibility.

[0047]

[0048] Example 3: To evaluate the performance of the composite insulated aerospace cable prepared above, we conducted the following tests on it: Test 1. Electrical Performance Test: Perform power frequency withstand voltage test, partial discharge test, and insulation resistance test on the cable to ensure that the cable can withstand 250kV voltage for 5 minutes without breakdown; partial discharge quantity ≤5pC; insulation resistance ≥10 15 The Ω·cm indicates that the cable has good electrical performance.

[0049] Test 2. Current carrying and thermal performance test: Under continuous current carrying conditions of 200A, a temperature rise test was conducted. The temperature rise of the conductor core was measured to be no more than 45℃, and there was no thermal runaway phenomenon, indicating that the cable has good thermal diffusion capability.

[0050] Test 3. Electrical performance test in a vacuum environment: at ≤10 -4 The surface flashover characteristics were tested under vacuum conditions. The flashover voltage was significantly increased and no surface discharge phenomenon was observed, indicating that the cable has good adaptability to vacuum environment.

[0051] Test 4. Wide Temperature Range and Mechanical Reliability Test: The cable was subjected to a cyclic test from -183℃ to 230℃ and a vibration test. No cracks were found in insulation layer 3, no degradation in electrical performance, and stable mechanical structure, indicating that the cable has good mechanical reliability in a wide temperature range.

[0052] Test 5. Radiation tolerance test: Under the condition of cumulative radiation dose ≥50Mrad, the mechanical properties of the insulation material retain ≥85%, and the electrical properties are stable without significant attenuation, indicating that the cable has good radiation resistance.

[0053]

[0054] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A novel composite insulated aerospace cable, its manufacturing method, and its application, characterized in that: include: Conductor core (1); An inner shielding layer (2) covers the outside of the conductor core (1); An insulating layer (3) is wrapped around the outside of the inner shielding layer (2); A metal shielding braided layer is wrapped around the outside of the insulating layer (3); The outer sheath (5) covers the outside of the metal shielding braided layer; Both the inner shielding layer (2) and the insulating layer (3) are made of irradiated crosslinked modified ETFE material doped with hydrophobic nano-silica.

2. The novel composite insulated aerospace cable according to claim 1, its manufacturing method and application, characterized in that: The modified ETFE material is doped with 0.05% hydrophobic nano-silica, wherein the hydrophobic nano-silica has a purity >99% metals basis, a particle size of 15 nm, and a specific surface area of ​​300±50 m². 2 / g.

3. The novel composite insulated aerospace cable according to claim 1, its manufacturing method and application, characterized in that: The formula for calculating the thickness of the insulating layer (3) is as follows: ； in, For insulation thickness, The voltage applied to the cable, The inner radius of the insulating layer (3) is This is the corrected breakdown field strength obtained after considering environmental factors such as vacuum and high temperature.

4. The novel composite insulated aerospace cable according to claim 2, characterized in that: At a vacuum degree of 10 -4 Under extreme aerospace environmental conditions with a temperature range of -183℃ to 230℃, the theoretical minimum thickness of the insulation layer (3) should not be less than 17.84mm.

5. A novel composite insulated aerospace cable according to claim 1, characterized in that: The conductor core (1) adopts a silver-plated copper stranded wire structure, which is formed by multiple silver-plated copper monofilaments concentrically twisted together; the thickness of the silver plating layer on the surface of the silver-plated copper monofilament is 2-3 μm; The inner shielding layer (2) has a thickness of 0.8 mm; The metal shielding braided layer adopts a silver-plated copper wire braided structure with a single wire diameter of 0.16 mm, a braiding coverage of 85% to 90%, and a braiding angle of 50° to 72°.

6. A novel composite insulated aerospace cable according to claim 5, characterized in that: The conductor core (1) adopts a two-stage concentric stranding structure: the first layer is a sub-bundle formed by concentrically stranding 19 single wires in a 1+6+12 pattern; the second layer is an integral conductor formed by further stranding more than 70 sub-bundles in a concentric layering manner; the outer diameter of the conductor core (1) is 11.176~12.065mm.

7. A novel composite insulated aerospace cable according to any one of claims 1-6, characterized in that: The outer sheath (5) is made of irradiated crosslinked modified ETFE material with a thickness of 1.5 mm.

8. A method for manufacturing a novel composite insulated aerospace cable, used to prepare the composite insulated aerospace cable according to claim 7, characterized in that: Includes the following steps: S1. Preparation of conductor core wire (1): The oxygen-free copper rod is drawn in multiple passes, then annealed and electroplated with silver layer, and then formed into conductor core wire by multiple strands concentrically twisted (1). S2, Extrusion of inner shielding layer (2): ETFE material doped with hydrophobic nano-silica is extruded and coated on the outside of the conductor core wire (1) to form inner shielding layer (2). S3, forming an insulating layer (3) and irradiating crosslinking: ETFE material doped with hydrophobic nano-silica is extruded and coated on the outside of the inner shielding layer (2), and after cooling and shaping, it is crosslinked by electron beam irradiation. S4, Braided metal shielding layer (4): Silver-plated copper wire is braided on the outside of the insulating layer (3); S5, Extruded outer sheath (5): Extruded and coated with irradiated crosslinked modified ETFE material on the outside of the metal shielding braided layer.

9. The manufacturing method of a novel composite insulated aerospace cable according to claim 8, characterized in that: The formula for calculating the irradiation dose in step 3 is: ； in, This is the cross-linking irradiation dose. The cross-linking-degradation ratio of the material. This refers to the maximum absorbed dose at the end of the cable's design life.

10. An application of a novel composite insulated aerospace cable, characterized in that: The composite insulated aerospace cable of claim 7 is applied to the high-voltage power transmission system of spacecraft. The voltage level of the spacecraft's high-voltage power transmission system is 200kV, and the current carrying capacity is 200A. The spacecraft is a space-based solar power station.

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