A crosslinked insulated medium voltage power cable

Abstract

The application relates to the technical field of cables, and discloses a cross-linked insulation medium-voltage power cable which is composed of a shielding wire core and a sheath layer wrapped outside the shielding wire core; the shielding wire core comprises, from inside to outside, a conductive wire core, a conductor shielding layer, a cross-linked insulation layer, an insulation shielding layer and a metal shielding layer; the sheath layer comprises 50-60 parts of thermoplastic polyurethane, 35-40 parts of low-density polyethylene, 15-20 parts of wear-resistant filler, 2-4 parts of antioxidant, 1-3 parts of lubricant and 2-4 parts of plasticizer; the wear-resistant filler comprises molybdenum disulfide composite attapulgite; the molybdenum disulfide composite attapulgite comprises the following components: molybdenum salt, thiourea, attapulgite and a surfactant. Through the technical scheme, the problem of poor wear resistance of the medium-voltage power cable in the related art is solved.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more specifically, to a cross-linked insulated medium-voltage power cable. Background Technology

[0002] Medium-voltage cross-linked polyethylene insulated power cables are widely used in key power supply scenarios such as urban power grids, industrial and mining power distribution, and rail transit. The cable laying environment is complex, often facing outdoor sun and rain, soil and rock scraping, ground dragging and crushing conditions. Therefore, in addition to basic insulation and weather resistance, the cable outer sheath must have excellent wear resistance, which is a key indicator to ensure the long-term safe service of the cable. The sheath layer is an important structure to improve the wear resistance of the cable.

[0003] Therefore, to improve the insufficient wear resistance of cable sheaths, existing technologies generally employ modification methods by adding inorganic fillers to the sheath matrix. However, the optimization effect of existing filler modification schemes is limited. After the cable has been in use for a period of time, the surface of the sheath suffers severe wear, and localized damage occurs frequently. Moisture and impurities can easily penetrate into the interior through the damaged areas, damaging the insulation structure and shortening the cable's service life. Therefore, there is an urgent need to develop a highly wear-resistant medium-voltage power cable. Summary of the Invention

[0004] This invention proposes a cross-linked insulated medium-voltage power cable to solve or alleviate at least one of the aforementioned problems.

[0005] The technical solution of the present invention is as follows: This invention proposes a cross-linked insulated medium-voltage power cable, comprising a shielded core and a sheath layer covering the shielded core; the shielded core, from the inside out, includes a conductive core, a conductor shielding layer, a cross-linked insulation layer, an insulating shielding layer, and a metallic shielding layer; the sheath layer comprises 50-60 parts of thermoplastic polyurethane, 35-40 parts of low-density polyethylene, 15-20 parts of abrasion-resistant filler, 2-4 parts of antioxidant, 1-3 parts of lubricant, and 2-4 parts of plasticizer; The wear-resistant filler includes a molybdenum disulfide composite attapulgite; The molybdenum disulfide composite attapulgite comprises the following components: molybdenum salt, thiourea, attapulgite, and surfactant.

[0006] Preferably, the material of the cross-linked insulating layer is cross-linked polyethylene.

[0007] Preferably, the metal shielding layer is obtained by wrapping metal foil or weaving metal wire; The metal includes any one of copper, tin-plated copper, aluminum, and aluminum alloys.

[0008] Preferably, the method for preparing the molybdenum disulfide composite attapulgite includes the following steps: The attapulgite rods were milled and dispersed in water. Molybdenum salt and thiourea were added and completely dissolved. Then, a surfactant was added and dissolved. The reaction system was transferred to a reaction vessel for hydrothermal reaction. After filtration, washing, and vacuum drying, the molybdenum disulfide composite attapulgite rods were obtained.

[0009] Preferably, the mass molar ratio of the attapulgite and sodium molybdate dihydrate is 1g:5~10mmol; The molar ratio of the molybdenum salt to thiourea is 1:4.5~6.

[0010] Preferably, the ball mill rotates at a speed of 250-350 rpm and the milling time is 4-6 hours.

[0011] Preferably, the surfactant comprises sodium fatty alcohol polyoxyethylene ether carboxylate and / or potassium monododecyl phosphate.

[0012] Preferably, when the surfactant is composed of sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate, the mass ratio of sodium fatty alcohol polyoxyethylene ether carboxylate to potassium monododecyl phosphate is 6:3~5.

[0013] Preferably, the wear-resistant filler also includes magnesium borate whiskers.

[0014] Preferably, the mass ratio of the molybdenum disulfide composite attapulgite to magnesium borate whiskers is 8:1~3.

[0015] The beneficial effects of this invention are as follows: This invention improves the wear resistance of the sheath layer by adding a molybdenum disulfide composite attapulgite prepared from molybdenum salt, thiourea, attapulgite, and surfactant. The wear-resistant filler uses attapulgite as a carrier, and utilizes the hydrothermal reaction of molybdenum salt and thiourea to generate molybdenum disulfide active components in situ, thus loading molybdenum disulfide onto the surface of the attapulgite. The attapulgite itself possesses excellent rigid structure and mechanical stability. When uniformly dispersed in the TPU / LDPE sheath matrix, it can construct a dense, rigid support skeleton within the resin, effectively resisting external impacts from friction, scratching, and extrusion, and limiting resin matrix deformation and wear. Simultaneously, the in-situ generated molybdenum disulfide possesses excellent solid lubrication properties, forming a lubricating protective layer at the sheath friction interface, reducing frictional loss of the sheath surface resin. Furthermore, the composite significantly reduces the phenomenon of molybdenum disulfide peeling or pull-out during friction, and the composite filler exhibits better dispersion. The synergistic effect of rigid anti-wear support from attapulgite and lubrication and friction reduction from molybdenum disulfide significantly improves the wear resistance of the cable sheath layer and effectively extends the service life of medium-voltage power cables. Detailed Implementation

[0016] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0017] A specific embodiment of the first aspect of the present invention provides a cross-linked insulated medium-voltage power cable, which consists of a shielded core and a sheath covering the shielded core; the shielded core includes, from the inside out, a conductive core, a conductor shielding layer, a cross-linked insulation layer, an insulating shielding layer and a metal shielding layer; The sheath layer comprises 50-60 parts of thermoplastic polyurethane, 35-40 parts of low-density polyethylene, 15-20 parts of wear-resistant filler, 2-4 parts of antioxidant, 1-3 parts of lubricant and 2-4 parts of plasticizer; Wear-resistant fillers include molybdenum disulfide composite attapulgite; Molybdenum disulfide composite attapulgite comprises the following components: molybdenum salt, thiourea, attapulgite, and surfactant.

[0018] In one embodiment of the present invention, the material of the cross-linked insulating layer is cross-linked polyethylene.

[0019] In one embodiment of the present invention, the metal shielding layer is obtained by wrapping metal foil or weaving metal wires; Metals include any one of copper, tin-plated copper, aluminum, and aluminum alloys.

[0020] In this invention, the metal shielding layer is a tin-plated copper wire braided layer; the tin plating layer can effectively prevent the copper material from oxidizing and rusting, and improve the shielding layer's resistance to damp heat.

[0021] In one embodiment of the present invention, the method for preparing a molybdenum disulfide composite attapulgite includes the following steps: After grinding and dispersing the attapulgite rods in water, molybdenum salt and thiourea were added to completely dissolve the molybdenum salt and thiourea. Then, a surfactant was added and dissolved. The reaction system was then transferred to a reactor for hydrothermal reaction, filtered, washed, and vacuum dried to obtain molybdenum disulfide composite attapulgite rods.

[0022] In one embodiment of the present invention, the mass molar ratio of attapulgite and sodium molybdate dihydrate is 1g:5~10mmol.

[0023] In one embodiment of the present invention, the molar ratio of molybdenum salt to thiourea is 1:4.5~6.

[0024] In one embodiment of the present invention, the ball mill rotation speed is 250~350 rpm, and the ball milling time is 4~6 hours.

[0025] In this invention, the molybdenum salt includes sodium molybdate dihydrate.

[0026] In this invention, the concentration of the surfactant in the reaction system is 0.5~3 mmol / L, for example, it can be any value or range between any two values ​​from 0.5 mmol / L, 0.8 mmol / L, 1 mmol / L, 1.2 mmol / L, 1.5 mmol / L, 1.8 mmol / L, 2 mmol / L, 2.2 mmol / L, 2.5 mmol / L, 2.8 mmol / L, to 3 mmol / L. This range ensures both stable loading of molybdenum disulfide and uniform dispersion of the filler in the thermoplastic polyurethane / low-density polyethylene system, thus stably achieving the synergistic effect of wear resistance.

[0027] In one embodiment of the invention, the surfactant comprises sodium fatty alcohol polyoxyethylene ether carboxylate and / or potassium monododecyl phosphate.

[0028] In one embodiment of the present invention, when the surfactant is composed of sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate, the mass ratio of sodium fatty alcohol polyoxyethylene ether carboxylate to potassium monododecyl phosphate is 6:3~5.

[0029] In this invention, the preferred surfactants are sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate. The synergistic effect of these two surfactants facilitates the stable adhesion of molybdenum disulfide to the attapulgite surface, reducing the probability of free molybdenum disulfide agglomeration. Simultaneously, the phosphate groups in potassium monododecyl phosphate can interact with the polar groups in thermoplastic polyurethane. Sodium fatty alcohol polyoxyethylene ether carboxylate, with its own flexible polyoxyethylene alkoxy chain, exhibits affinity and compatibility with the non-polar segments of low-density polyethylene, improving the wetting and dispersibility of the attapulgite / molybdenum disulfide composite filler in the polymer. Therefore, when this composite filler is applied to cable sheaths, its excellent compatibility and dispersibility further enhance the cable's abrasion resistance. Furthermore, within this mass ratio range, the synergistic effect of the two surfactants is optimal.

[0030] In one embodiment of the present invention, the wear-resistant filler further includes magnesium borate whiskers.

[0031] In this invention, the molybdenum disulfide composite attapulgite mainly plays a self-lubricating and load-bearing role, while the magnesium borate whiskers, as a one-dimensional rigid reinforcement, can penetrate into the polymer matrix to form a dense three-dimensional reinforcement network, effectively sharing the shear stress during the friction process and inhibiting the plastic deformation and crack propagation of the matrix. Therefore, by combining magnesium borate whiskers and molybdenum disulfide composite attapulgite together as wear-resistant fillers, the wear resistance of the sheath layer can be further improved.

[0032] In one embodiment of the present invention, the mass ratio of molybdenum disulfide composite attapulgite to magnesium borate whiskers is 8:1~3.

[0033] In this invention, the synergistic effect of the two materials is best when the mass ratio of molybdenum disulfide composite attapulgite to magnesium borate whiskers is limited to 8:1~3. When the proportion of molybdenum disulfide composite attapulgite is too high, the reinforcing skeleton effect of magnesium borate whiskers is insufficient, and the improvement of wear resistance is limited; when the proportion of magnesium borate whiskers is too high, it is easy to cause agglomeration and increase the brittleness of the material.

[0034] In this invention, the antioxidant includes one or more of phenolic antioxidants, phosphite antioxidants, and thioether antioxidants. Phenolic antioxidants may be, for example, at least one of antioxidant 1010, antioxidant 330, antioxidant 1076, and antioxidant BHT; phosphite antioxidants may be, for example, at least one of antioxidant 168, triphenyl phosphite, and antioxidant 626; thioether antioxidants may be, for example, at least one of dilauryl thiodipropionate and dioctadecyl thiodipropionate. The antioxidants can inhibit the thermo-oxidative degradation of thermoplastic polyurethane and low-density polyethylene during high-temperature extrusion processing and long-term outdoor use, delaying sheath cracking, mechanical and abrasion resistance degradation, and extending the service life of the cable sheath layer.

[0035] In this invention, the lubricant includes one or more of fatty acid lubricants, polyethylene wax, oxidized polyethylene wax, and stearate lubricants. Fatty acid lubricants may be, for example, at least one of stearic acid and palmitic acid; fatty acid ester lubricants may be, for example, at least one of pentaerythritol stearate and glyceryl monostearate; stearate lubricants may be, for example, at least one of zinc stearate and calcium stearate. The lubricant improves the flowability of the sheath material during extrusion processing, reduces molding friction defects, ensures uniform dispersion of fillers, and stabilizes the wear resistance of the sheath.

[0036] In this invention, the plasticizer includes one or more of phthalate esters, aliphatic diester esters, and epoxy plasticizers; phthalate esters may be, for example, at least one of dibutyl phthalate and dioctyl phthalate; aliphatic diester esters may be, for example, at least one of dioctyl adipate and dibutyl sebacate; and epoxy plasticizers may be, for example, at least one of epoxidized soybean oil and epoxidized fatty acid methyl esters. The plasticizer can improve the resin processing fluidity, enhance the dispersion effect of wear-resistant fillers in the matrix, and balance the flexibility and wear resistance stability of the sheath.

[0037] A second aspect of the present invention provides a method for preparing a cross-linked insulated medium-voltage power cable, used to prepare the cross-linked insulated medium-voltage power cable provided in the first aspect of the present invention, comprising the following steps: S1. A conductor shielding layer is set outside the conductor core. Cross-linked polyethylene material is extruded outside the conductor shielding layer to form a cross-linked insulation layer. Tinned copper wire is braided outside the cross-linked insulation layer to form a metal shielding layer, thereby obtaining a shielded core. S2. Thermoplastic polyurethane, low-density polyethylene, wear-resistant filler, antioxidant, lubricant and plasticizer are mixed evenly to obtain a uniformly dispersed sheathing composite material. The sheathing composite material is fed into an extruder and, after being melted and plasticized, is uniformly extruded to cover the outside of the metal shielding layer of the shielding core to form a sheathing layer. After cooling and shaping, and traction winding, a cross-linked insulated medium-voltage power cable is obtained.

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will be described through embodiments.

[0039] In the following examples and comparative examples, the thermoplastic polyurethane is Elastollan® 1385 A; the low-density polyethylene is 2102TN00; the average particle size of the attapulgite is 3 μm; and the length of the magnesium borate whiskers is 20 μm with an aspect ratio of 30.

[0040] Example 1 The cross-linked insulated medium-voltage power cable consists of a shielded core and a sheath covering the shielded core. The shielded core, from the inside out, includes a conductive core, a conductor shielding layer, a cross-linked insulation layer, an insulating shielding layer, and a metallic shielding layer. The sheath layer includes 50 parts of thermoplastic polyurethane, 35 parts of low-density polyethylene, 15 parts of abrasion-resistant filler, 1 part of antioxidant 1010, 1 part of antioxidant 168, 1 part of pentaerythritol stearate, and 2 parts of epoxidized soybean oil. The abrasion-resistant filler includes molybdenum disulfide composite attapulgite. The preparation method of molybdenum disulfide composite attapulgite includes the following steps: After ball milling attapulgite at 250 rpm for 6 h, it was dispersed in water (attapulgite to water mass-volume ratio of 1 g: 150 mL). Sodium molybdate dihydrate and thiourea (molar ratio of attapulgite to sodium molybdate dihydrate of 1 g: 5 mmol) were added in a molar ratio of 1:4.5 to completely dissolve the molybdenum salt and thiourea. Then, sodium fatty alcohol polyoxyethylene ether carboxylate was added, and the surfactant was dissolved by sonication (the concentration of surfactant in the reaction system was 1.5 mmol / L). The reaction system was then transferred to a reaction vessel and hydrothermally reacted at 180 °C for 24 h. After filtration, washing, and vacuum drying, molybdenum disulfide composite attapulgite was obtained. A method for preparing cross-linked insulated medium-voltage power cables includes the following steps: S1. A conductor shielding layer is set outside the conductor core. Cross-linked polyethylene material is extruded outside the conductor shielding layer to form a cross-linked insulation layer. Tinned copper wire is braided outside the cross-linked insulation layer to form a metal shielding layer, thereby obtaining a shielded core. S2. Thermoplastic polyurethane, low-density polyethylene, abrasion-resistant filler, antioxidant 1010, antioxidant 168, pentaerythritol stearate and epoxidized soybean oil are mixed evenly to obtain a uniformly dispersed sheathing composite material. The sheathing composite material is fed into an extruder, melted and plasticized, and then uniformly extruded to cover the outside of the metal shielding layer of the shielded core to form a sheathing layer. After cooling and shaping, and traction winding, a cross-linked insulated medium-voltage power cable is obtained.

[0041] Example 2 The cross-linked insulated medium-voltage power cable consists of a shielded core and a sheath covering the shielded core. The shielded core, from the inside out, includes a conductive core, a conductor shielding layer, a cross-linked insulation layer, an insulating shielding layer, and a metallic shielding layer. The sheath layer includes 60 parts of thermoplastic polyurethane, 40 parts of low-density polyethylene, 20 parts of abrasion-resistant filler, 2 parts of antioxidant 1010, 2 parts of antioxidant 168, 3 parts of pentaerythritol stearate, and 4 parts of epoxidized soybean oil. The abrasion-resistant filler includes molybdenum disulfide composite attapulgite. The preparation method of molybdenum disulfide composite attapulgite includes the following steps: After ball milling attapulgite at 350 rpm for 4 h, it was dispersed in water (attapulgite to water mass-volume ratio of 1 g: 150 mL). Sodium molybdate dihydrate and thiourea in a molar ratio of 1:6 (attapulgite to sodium molybdate dihydrate mass-volume ratio of 1 g: 10 mmol) were added to completely dissolve the molybdenum salt and thiourea. Then, sodium fatty alcohol polyoxyethylene ether carboxylate was added, and the surfactant was dissolved by sonication (the surfactant concentration in the reaction system was 1.5 mmol / L). The reaction system was then transferred to a reaction vessel and hydrothermally reacted at 180 °C for 24 h. After filtration, washing, and vacuum drying, molybdenum disulfide composite attapulgite was obtained. A method for preparing cross-linked insulated medium-voltage power cables includes the following steps: S1. A conductor shielding layer is set outside the conductor core. Cross-linked polyethylene material is extruded outside the conductor shielding layer to form a cross-linked insulation layer. Tinned copper wire is braided outside the cross-linked insulation layer to form a metal shielding layer, thereby obtaining a shielded core. S2. Thermoplastic polyurethane, low-density polyethylene, abrasion-resistant filler, antioxidant 1010, antioxidant 168, pentaerythritol stearate and epoxidized soybean oil are mixed evenly to obtain a uniformly dispersed sheathing composite material. The sheathing composite material is fed into an extruder, melted and plasticized, and then uniformly extruded to cover the outside of the metal shielding layer of the shielded core to form a sheathing layer. After cooling and shaping, and traction winding, a cross-linked insulated medium-voltage power cable is obtained.

[0042] Example 3 The cross-linked insulated medium-voltage power cable consists of a shielded core and a sheath covering the shielded core. The shielded core, from the inside out, includes a conductive core, a conductor shielding layer, a cross-linked insulation layer, an insulating shielding layer, and a metallic shielding layer. The sheath layer includes 55 parts of thermoplastic polyurethane, 38 parts of low-density polyethylene, 18 parts of abrasion-resistant filler, 1.5 parts of antioxidant 1010, 1.5 parts of antioxidant 168, 2 parts of pentaerythritol stearate, and 3 parts of epoxidized soybean oil. The abrasion-resistant filler includes molybdenum disulfide composite attapulgite. The preparation method of molybdenum disulfide composite attapulgite includes the following steps: After ball milling attapulgite at 300 rpm for 3 h, it was dispersed in water (attapulgite to water mass-volume ratio of 1 g: 150 mL). Sodium molybdate dihydrate and thiourea in a molar ratio of 1:5 (attapulgite to sodium molybdate dihydrate mass-volume ratio of 1 g: 8 mmol) were added to completely dissolve the molybdenum salt and thiourea. Then, sodium fatty alcohol polyoxyethylene ether carboxylate was added, and the surfactant was dissolved by sonication (the surfactant concentration in the reaction system was 1.5 mmol / L). The reaction system was then transferred to a reaction vessel and hydrothermally reacted at 180 °C for 24 h. After filtration, washing, and vacuum drying, molybdenum disulfide composite attapulgite was obtained. A method for preparing cross-linked insulated medium-voltage power cables includes the following steps: S1. A conductor shielding layer is set outside the conductor core. Cross-linked polyethylene material is extruded outside the conductor shielding layer to form a cross-linked insulation layer. Tinned copper wire is braided outside the cross-linked insulation layer to form a metal shielding layer, thereby obtaining a shielded core. S2. Thermoplastic polyurethane, low-density polyethylene, abrasion-resistant filler, antioxidant 1010, antioxidant 168, pentaerythritol stearate and epoxidized soybean oil are mixed evenly to obtain a uniformly dispersed sheathing composite material. The sheathing composite material is fed into an extruder, melted and plasticized, and then uniformly extruded to cover the outside of the metal shielding layer of the shielded core to form a sheathing layer. After cooling and shaping, and traction winding, a cross-linked insulated medium-voltage power cable is obtained.

[0043] Example 4 Except for replacing sodium fatty alcohol polyoxyethylene ether carboxylate with an equal amount of potassium monododecyl phosphate, the rest is the same as in Example 2.

[0044] Example 5 Except for replacing sodium fatty alcohol polyoxyethylene ether carboxylate with sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate in a mass ratio of 6:3, the rest is the same as in Example 2.

[0045] Example 6 Except for replacing sodium fatty alcohol polyoxyethylene ether carboxylate with sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate in a mass ratio of 6:5, the rest is the same as in Example 2.

[0046] Example 7 Except for the fact that the wear-resistant filler is composed of molybdenum disulfide composite attapulgite and magnesium borate whiskers in a mass ratio of 16:1, the rest is the same as in Example 5.

[0047] Example 8 Except for the fact that the wear-resistant filler is composed of molybdenum disulfide composite attapulgite and magnesium borate whiskers in a mass ratio of 2:1, the rest is the same as in Example 5.

[0048] Example 9 Except for the fact that the wear-resistant filler is composed of molybdenum disulfide composite attapulgite and magnesium borate whiskers in a mass ratio of 8:1, the rest is the same as in Example 5.

[0049] Example 10 Except for the fact that the wear-resistant filler is composed of molybdenum disulfide composite attapulgite and magnesium borate whiskers in a mass ratio of 8:3, the rest is the same as in Example 5.

[0050] Comparative Example 1 Except that the wear-resistant filler is composed of attapulgite and molybdenum disulfide in a mass ratio of 1:1.6, the rest is the same as in Example 2.

[0051] Comparative Example 2 Except for the fact that the wear-resistant filler is magnesium borate whiskers, everything else is the same as in Example 2.

[0052] The following performance tests were performed on the sheath layers of Examples 1-10 and Comparative Examples 1-2: Wear resistance: The mass wear of the sheath specimen was tested according to GB / T 3960-2016 "Test Method for Sliding Friction and Wear of Plastics"; The test results are shown in Table 1 below.

[0053] Table 1 Test Results

[0054] Examples 1-6 show that by adding the prepared molybdenum disulfide composite attapulgite to the cable sheath layer, the wear quality of the resulting sheath layer is less than that of Comparative Example 1. This indicates that adding molybdenum disulfide composite attapulgite to the sheath layer can improve the wear resistance of the cable. Furthermore, in Examples 5-6, when preparing the molybdenum disulfide composite attapulgite, the surfactant is preferably a combination of sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate. The wear quality of the resulting sheath layer is less than that of Examples 1-4. This indicates that the combination of sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate can further improve the wear resistance of the cable.

[0055] Examples 9-10 use a combination of molybdenum disulfide composite attapulgite and magnesium borate whiskers as wear-resistant fillers. Through the synergistic effect of the two and by optimizing their mass ratio to 8:1-3, the wear mass of the sheath layer is less than that of Examples 5, 7-8 and Comparative Example 2. This shows that adding molybdenum disulfide composite attapulgite and magnesium borate whiskers in a mass ratio of 8:1-3 to the sheath layer can improve the wear resistance of the cable.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cross-linked insulated medium-voltage power cable, characterized in that, It consists of a shielded core and a sheath layer covering the shielded core; the shielded core includes, from the inside out, a conductive core, a conductor shielding layer, a cross-linked insulation layer, an insulating shielding layer, and a metal shielding layer; the sheath layer includes 50-60 parts of thermoplastic polyurethane, 35-40 parts of low-density polyethylene, 15-20 parts of wear-resistant filler, 2-4 parts of antioxidant, 1-3 parts of lubricant, and 2-4 parts of plasticizer; The wear-resistant filler includes a molybdenum disulfide composite attapulgite; The molybdenum disulfide composite attapulgite comprises the following components: molybdenum salt, thiourea, attapulgite, and surfactant.

2. The cross-linked insulated medium-voltage power cable according to claim 1, characterized in that, The material of the cross-linked insulating layer is cross-linked polyethylene.

3. The cross-linked insulated medium-voltage power cable according to claim 1, characterized in that, The metal shielding layer is made by wrapping metal foil or weaving metal wire; The metal includes any one of copper, tin-plated copper, aluminum, and aluminum alloys.

4. A cross-linked insulated medium-voltage power cable according to claim 1, characterized in that, The preparation method of the molybdenum disulfide composite attapulgite includes the following steps: The attapulgite rods were milled and dispersed in water. Molybdenum salt and thiourea were added and completely dissolved. Then, a surfactant was added and dissolved. The reaction system was transferred to a reaction vessel for hydrothermal reaction. After filtration, washing, and vacuum drying, the molybdenum disulfide composite attapulgite rods were obtained.

5. A cross-linked insulated medium-voltage power cable according to claim 4, characterized in that, The mass molar ratio of the attapulgite and sodium molybdate dihydrate is 1g:5~10mmol; The molar ratio of the molybdenum salt to thiourea is 1:4.5~6.

6. A cross-linked insulated medium-voltage power cable according to claim 4, characterized in that, The ball mill rotates at 250-350 rpm and the milling time is 4-6 hours.

7. A cross-linked insulated medium-voltage power cable according to claim 4, characterized in that, The surfactants include sodium fatty alcohol polyoxyethylene ether carboxylate and / or potassium monododecyl phosphate.

8. A cross-linked insulated medium-voltage power cable according to claim 7, characterized in that, When the surfactant is composed of sodium fatty alcohol polyoxyethylene ether carboxylate and potassium monododecyl phosphate, the mass ratio of sodium fatty alcohol polyoxyethylene ether carboxylate to potassium monododecyl phosphate is 6:3~5.

9. A cross-linked insulated medium-voltage power cable according to claim 1, characterized in that, The wear-resistant filler also includes magnesium borate whiskers.

10. A cross-linked insulated medium-voltage power cable according to claim 9, characterized in that, The mass ratio of the molybdenum disulfide composite attapulgite to magnesium borate whiskers is 8:1~3.

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