Cable insulating material for 6-15kV coal mining machinery and cable

Abstract

The invention provides a cable insulating material for 6-15kV coal mining machinery. The cable insulating material is prepared from the following raw materials in parts by weight: 60-80 parts of EPM, 20-40 parts of LDPE, 10-20 parts of zinc oxide, 1-3 parts of stearic acid, 3-6 parts of microcrystalline wax, 10-20 parts of spherical boron nitride, 10-20 parts of modified boron nitride, 20-40 parts of modified kaolin, 2-4 parts of an anti-aging agent, 1-2 parts of a coupling agent, 10-20 parts of paraffin oil, 2-3 parts of a vulcanizing agent and 0.5-1.5 parts of an assistant crosslinking agent. The cable for the intelligent coal mining machinery is prepared by adopting the insulating material, the cable for the coal mining machinery comprises a cable core and a sheath layer wrapping the cable core, and the cable core is formed by twisting three power wire cores and three groups of communication wire cores around a central special-shaped bracket; the center of the special-shaped support comprises multiple optical fibers. According to the cable for the 6-15 kV voltage grade coal mining machinery, the high voltage grade can be safely and stably applied to the severe coal mining working condition, compared with the current highest 3.3 kV, the sectional area of the cable of the coal mining machine can be greatly reduced, the use cost of a user is reduced, and the use experience of the user is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and specifically, to a cable insulating material and a cable for a coal mining machine with a voltage of 6 - 15 kV. Background Art

[0002] The coal mine cable standard MT818 stipulates that the two voltage levels of the shearer cable are 1.14 kV and 3.3 kV respectively. In the past, due to the generally low power of coal mining machinery, the current-carrying capacity of the cable did not need to be too high, and this low-voltage-level shearer cable fully met the mining requirements. With the progress of technology, the power of coal mining machinery has become higher and higher, and accordingly, the cross-sectional area of the cable for coal mining machinery has gradually transitioned from a small cross-section to 240 mm 2 or even 300 mm 2 and above. This brings great inconvenience to coal mine users because the larger the cross-sectional area, the larger the outer diameter of the cable, and the weight of the cable increases significantly, with the weight per meter of the cable reaching more than 15 kg, bringing great inconvenience to the installation, laying, and use of the cable.

[0003] If we want to reduce the cross-sectional area of the cable at the same power, we must increase the system voltage to be equivalent to the commonly used 6 - 15 kV voltage in the mining industry. For example, for a shearer with a total installed power of 1500 kW, calculated according to the highest voltage level of the shearer cable specified in the current MT 818 standard, which is 1.9 / 3.3 kV, the single-phase power line current-carrying capacity is about 310 A. According to Table B.1 in Appendix B of MT818.1 standard, the cross-sectional area of the power line needs to be selected as 150 mm 2 . If the system voltage can be increased to 6 / 10 kV, then the single-phase current-carrying capacity is about 98 A. At this time, the cross-sectional area of the power line only needs to be selected as 25 mm 2 and that's it. This can greatly reduce the cross-sectional area of the cable power line, achieving the effects of cost savings and reducing the weight per unit length of the cable. However, considering the special harsh working conditions of the cable for coal mining machinery, increasing the voltage necessarily requires providing more voltage-resistant and better-performing insulating materials to ensure that the cable is not punctured under mechanical stress such as stretching, bending, impact, and extrusion. Considering that the damage of high-voltage cable insulation is often caused by the decrease in the insulation performance of the cable resulting in being punctured by high voltage, and the decrease in insulation performance is largely related to the temperature rise of the cable during actual use.

[0004] Patent CN 118116650B describes a 10 kV high-performance shearer cable and its manufacturing process, which focuses on the process environmental hygiene during the cable production process. Its insulating material formula has no obvious difference from the traditional insulation for fixed laying, and it cannot solve the problem of high-voltage breakdown of insulation under harsh working conditions. Summary of the Invention

[0005] Aiming at the defects in the prior art, the purpose of the present invention is to provide a cable insulating material and a cable for 6-15 kV coal mining machinery.

[0006] The purpose of the present invention is achieved through the following solutions:

[0007] The first aspect of the present invention provides a cable insulating material for 6-15 kV coal mining machinery, comprising the following raw materials in parts by weight: 60-80 parts of EPM, 20-40 parts of LDPE, 10-20 parts of zinc oxide, 1-3 parts of stearic acid, 3-6 parts of microcrystalline wax, 10-20 parts of spherical boron nitride, 10-20 parts of modified boron nitride, 20-40 parts of modified kaolin, 2-4 parts of antioxidant, 1-2 parts of coupling agent, 10-20 parts of paraffin oil, 2-3 parts of vulcanizing agent, 0.5-1.5 parts of co-crosslinking agent.

[0008] Preferably, the antioxidant is selected from at least one of 1010, MB, and RD, the coupling agent is selected from at least one of silane coupling agent KH550 and A172, the vulcanizing agent is selected from at least one of BIBP and DCP, and the co-crosslinking agent is selected from at least one of TAIC and PL400.

[0009] Preferably, the cable insulating material comprises the following raw materials in parts by weight: 72 parts of EPM, 20 parts of LDPE, 20 parts of zinc oxide, 3 parts of stearic acid, 6 parts of microcrystalline wax, 10 parts of spherical boron nitride, 20 parts of modified boron nitride, 20 parts of modified kaolin, 4 parts of antioxidant, 2 parts of coupling agent, 20 parts of paraffin oil, 3 parts of vulcanizing agent, 0.5 part of co-crosslinking agent.

[0010] The spherical boron nitride S-BN is a polycrystalline sphere composed of boron nitride micron-scale single crystal wafers, with good fluidity and can improve the anisotropic thermal conductivity performance; the surface area of the spherical boron nitride particles is relatively small, which can make the addition amount of boron nitride in the polymer higher, and thus obtain higher thermal conductivity performance.

[0011] The modified boron nitride SM-BN has better compatibility with rubber, plastics, and resins, and can effectively improve the mechanical properties and electrical properties of the insulating material. The addition of the coupling agent A172 can further reduce the surface polarity of boron nitride and improve the compatibility with the matrix material.

[0012] The second aspect of the present invention provides a 6-15 kV coal mining machinery cable comprising the insulating material provided in the first aspect, comprising a cable core and a sheath layer covering the cable core. The cable core is stranded by three power cores and three groups of communication cores around a central special-shaped bracket; the central part of the special-shaped bracket contains multiple optical fibers; preferably 4-12 high-flexibility optical fibers.

[0013] The power cable core includes an insulated core and a composite shielding layer. The insulated core is formed by co-extrusion of a power cable conductor, a conductor shielding layer, an insulating layer, and an insulation shielding layer. The composite shielding layer is wrapped around the outside of the insulation shielding layer. The insulating layer is made of the insulating material provided in the first aspect. The conductor shielding layer is a semiconductive adhesive made by blending ethylene propylene rubber and EVA. The insulation shielding layer is a semiconductive adhesive based on NBR or EVA.

[0014] Preferably, when the sheath is a single-layer sheath, there is no fiber braided reinforcement layer. When there is a large torque during the use of the cable, the sheath layer includes an inner sheath, a fiber braided reinforcement layer, and an outer sheath arranged from inside to outside. The sheath material can be one or several of chlorinated polyethylene rubber, chloroprene rubber, and thermoplastic polyurethane.

[0015] Preferably, the composite shielding layer includes a copper foil wrapped around the insulation shielding layer, a metal braided layer outside the copper foil, and an aluminum foil wrapped around the metal braided layer. The metal braided layer is preferably a copper wire / fiber hybrid braided structure.

[0016] Preferably, the wrapping overlap rates of the copper foil and the aluminum foil are both greater than 20% and less than or equal to 50%.

[0017] Through the above technical solution, copper foil and aluminum foil wrapping layers are arranged on the inner and outer sides of the metal braided layer, greatly improving the shielding efficiency of the cable, enhancing the safety of the cable itself and the internal control and communication components of the equipment, ensuring the stability and accuracy of data transmission, and reducing signal distortion and error rate.

[0018] Preferably, the communication cable core includes a communication cable conductor, a communication cable insulating layer, a communication cable sheath layer, a ground wire conductor, and a ground wire semiconductive adhesive arranged from inside to outside. The ground wire conductor is helically wound around the outside of the communication cable sheath layer. The communication cable insulating layer and the communication cable sheath layer are coated by the rubber extrusion method commonly used in the cable industry.

[0019] Preferably, the covering density of the helical winding of the ground wire conductor is greater than 85% and less than or equal to 100%.

[0020] Through the above technical solution, the ground wire is arranged around the communication cable and the control cable, and is arranged in a helical winding and high-coverage manner, which can effectively shield the electromagnetic interference generated by the power cable and ensure the safe transmission of communication data.

[0021] The lay ratio of the cable prepared by the present invention is 5 to 14 times to meet the use of the cable in frequently bent occasions.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. For the cable insulation material of the present invention, LDPE with a relatively high thermal conductivity in polymers and good compatibility with EPM is selected as the second matrix, and its thermal conductivity is greater than that of the commonly used ethylene - propylene rubber. At the same time, the present invention creatively selects two different structures of boron nitride as the second and third reinforcing filler materials, and their thermal conductivities reach about 300 W·(m·k), which is much higher than the thermal conductivity of conventional clay. Among them, the modified boron nitride has better compatibility and reinforcing effect with EPM, while the spherical boron nitride mainly plays the role of filling and improving the fluidity of the material. With the coupling agent, it has good mechanical property performance in the system. The excellent thermal conductivity of the insulation material of the present invention greatly improves the heat conduction performance of the insulation material and extends the insulation service life. -1 Around, far higher than the thermal conductivity of conventional clay. Among them, the modified boron nitride has better compatibility and reinforcing effect with EPM, while the spherical boron nitride mainly plays the role of filling and improving the fluidity of the material. With the coupling agent, it has good mechanical property performance in the system. The excellent thermal conductivity of the insulation material of the present invention greatly improves the heat conduction performance of the insulation material and extends the insulation service life.

[0024] 2. For the cable of the present invention, on the basis of the structure of ordinary high - voltage cables, copper foil and aluminum foil wrapping layers are added inside and outside the power line braided layer. Compared with ordinary high - voltage cables, the shielding efficiency of the cable of the present invention is greatly improved, which can effectively shield the interference generated by the electromagnetic field under high - voltage conditions, improve the safety of the cable itself and the internal control and communication components of the equipment, ensure the stability and accuracy of data transmission, and reduce signal distortion and bit error rate. At the same time, the present invention arranges the ground wire around the communication line in a winding and high - coverage manner, which can effectively shield the electromagnetic interference generated by the power line and ensure the safe transmission of communication data.

[0025] 3. The cable for coal mining machinery with a voltage grade of 6 - 15 kV provided by the present invention enables high - voltage grades to be safely and stably applied to coal - mining working conditions with harsh working conditions. Without changing the power of the coal - mining machinery, the cross - sectional area of the cable of the coal - mining machine can be greatly reduced, reducing the user's usage cost and improving the user's usage experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the double - layer sheath cable structure of the present invention;

[0027] Figure 2 It is a schematic diagram of the single - layer sheath cable structure of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0029] The object of the present invention is to provide a cable for coal mining machinery with a voltage level of 6 - 15 kV, enabling the high voltage level to be safely and stably applied to the coal mining working conditions with harsh working conditions. Compared with the current highest 3.3 kV, the cross-sectional area of the cable for the shearer can be significantly reduced, the user's usage cost can be lowered, and the user's usage experience can be improved.

[0030] The present invention provides a cable for coal mining machinery with a voltage of 6 - 15 kV, which includes a cable core and a sheath layer wrapped around the cable core. Among them, the cable core is stranded by three power cores 2 and three groups of communication cores 1 around a central special-shaped support 3; the center of the special-shaped support contains 4 - 12 highly flexible optical fibers. Among them, the special-shaped support is made of semiconductive rubber, which can be one or a mixture of EVA, NBR, CPE, and CR. As Figure 2 shown, when the sheath layer is a single-layer sheath, there is no fiber braided reinforcement layer; when there is a large torque during the use of the cable, as Figure 1 shown, the sheath layer includes an inner sheath 51, a fiber braided reinforcement layer 52, and an outer sheath 53 arranged from the inside out. Each layer can adopt the conventional covering method in the cable production process. The materials of the inner sheath and the outer sheath are usually of the same kind, which can be one or a mixture of chlorinated polyethylene rubber, chloroprene rubber, and thermoplastic polyurethane. The material of the fiber braided reinforcement layer is generally polyester fiber or aramid fiber.

[0031] The three power cores 2 include insulated cores and a composite shielding layer 25. The insulated core is formed by co-extrusion of a power conductor 21, a conductor shielding layer 22, an insulating layer 23, and an insulation shielding layer 24. Outside the power conductor 21, the conductor shielding layer 22, the insulating layer 23, and the insulation shielding layer 24 are arranged in sequence from the inside out. The power conductor can be one or a mixture of materials such as copper, aluminum, or aluminum alloy. The conductor shielding layer 22 is a semiconductive rubber made of ethylene propylene rubber or a mixture of ethylene propylene rubber and POE or EVA. The insulation shielding layer 24 can be a semiconductive rubber formed by one or a mixture of EVA, NBR, CPE, and CR. The composite shielding layer 25 includes a copper foil wrapped around the insulation shielding layer 24, a metal braided layer outside the copper foil, and an aluminum foil wrapped around the metal braided layer. Among them, the wrapping overlap rates of the copper foil and the aluminum foil are both greater than 20%, and the metal braided layer is a copper wire / fiber hybrid braided structure.

[0032] The communication wire core 1 includes a communication wire conductor 14, a communication wire insulation layer 15, a communication wire sheath layer 13, a ground wire conductor 12, and a ground wire semi-conductive adhesive 11 arranged from the inside out. Among them, the ground wire conductor 12 is spirally wound outside the communication wire sheath layer 13, and the coverage density is greater than 85%; the communication wire insulation layer 15 can be an insulating material with a small dielectric constant such as fluoroplastics or cross-linked polyethylene, and the communication wire sheath layer 13 is usually one or a mixture of materials such as CPE, CR, or ethylene-propylene rubber, and they are all coated by the rubber extrusion method commonly used in the cable industry. The communication wire conductor and the ground wire conductor can be one or a mixture of materials such as copper, aluminum, or aluminum alloy, and the material of the ground wire semi-conductive adhesive is the same as that of the special-shaped bracket.

[0033] The brief preparation process steps of the cable of the present invention are as follows:

[0034] 1. The power line, communication line, and ground wire conductor are stranded on a high-speed stranding machine and then stranded on a cage stranding machine to obtain a finished conductor.

[0035] 2. The cable insulation is kneaded according to the following process: Pour all other materials except the vulcanizing agent into the internal mixer at one time and knead for 5-7 minutes, lift the upper plug to sweep the material, and repeat twice, then continue to knead until the temperature shows 120°C, discharge the kneaded rubber to the open mill for turning and kneading, and then take out the sheet without cutting.

[0036] After cooling, it is re-invested in the internal mixer to add the vulcanizing agent for kneading, control the kneading time to 1 minute, control the kneading temperature below 90°C, and take out the sheet on a three-roll calender to obtain the finished kneaded rubber.

[0037] 3. After the finished product is placed for 16 hours, it is put into the continuous vulcanization process. During the continuous vulcanization extrusion process, control the temperature of the extruder to be 65-90°C, the vulcanization steam pressure to be 1.5 MPa, and the traction speed to be 10-15 m / min. Outside the power line conductor 21, the raw materials of the conductor shielding layer 22, the finished insulation kneaded rubber, and the raw materials of the insulation shielding layer 24 are co-extruded to obtain an insulated wire core. The communication wire finished product and the central special-shaped bracket are obtained according to the same process parameter conditions. Specifically, outside the communication wire conductor 14, the communication wire insulation layer 15, the communication wire sheath layer 13, the ground wire conductor 12, and the ground wire semi-conductive adhesive 11 are co-extruded to obtain the communication wire core 1.

[0038] 4. A copper foil, a braided copper wire / fiber braided layer, an aluminum foil wrap, etc. are wound outside the insulated wire core as a composite shielding layer to obtain a power line core 2.

[0039] 5. Three power line cores and three groups of communication line cores are assembled around the central special-shaped bracket on a cabling device to obtain a cable core.

[0040] 6. Go back to the continuous vulcanization process again. Extrude the sheath compound around the cable core to obtain the finished cable. If it is a double-sheath structure, first extrude the inner sheath around the cable core, then apply a fiber braided reinforcement layer outside the inner sheath, and finally extrude the outer sheath outside to obtain the finished cable.

[0041] For the cable of the present invention, on the basis of the structure of a common high-voltage cable, copper foil and aluminum foil wrapping layers are added on the inner and outer sides of the power line braided layer. Compared with the common high-voltage cable, the shielding efficiency of the cable of the present invention is greatly improved, and the cable transfer impedance and shielding attenuation meet the standard requirements of vehicle high-voltage cables. It can effectively shield the interference generated by the electromagnetic field under high voltage, improve the safety of the cable itself and the internal control and communication components of the equipment, ensure the stability and accuracy of data transmission, and reduce signal distortion and bit error rate. At the same time, the present invention arranges the ground wire around the communication line in a winding and high-coverage manner, which can effectively shield the electromagnetic interference generated by the power line and ensure the secure transmission of communication data.

[0042] Considering that the damage of the high-voltage cable insulation is often caused by the decrease of the cable insulation performance resulting in breakdown by high voltage, and the decrease of the insulation performance is largely related to the temperature rise of the cable during actual use. Therefore, the purpose of the present invention is to solve how to improve the heat conduction performance of the insulation, so as to ensure that the insulation has a lower temperature rise under the same current-carrying condition of the cable.

[0043] Based on this, the present invention uses the following cable insulation material formula to make the insulation layer of the power line core:

[0044] The power line insulation material formula is as follows: 72260 - 80 parts of EPM (ethylene propylene rubber), 20 - 40 parts of LDPE (low density polyethylene), 10 - 20 parts of zinc oxide, 1 - 3 parts of stearic acid, 3 - 6 parts of microcrystalline wax, 10 - 20 parts of spherical boron nitride S-BN, 10 - 20 parts of modified boron nitride SM-BN, 20 - 40 parts of modified kaolin, 2 - 4 parts of antioxidant, 1 - 2 parts of coupling agent A172, 10 - 20 parts of paraffin oil, 2 - 3 parts of vulcanizing agent BIBP, 0.5 - 1.5 parts of co-crosslinking agent TAIC.

[0045] Among them, the spherical boron nitride S-BN is a polycrystalline sphere composed of boron nitride micron-sized single crystal wafers, with good fluidity and can improve the anisotropic performance of heat conduction; the surface area of the spherical boron nitride particles is smaller, which can make the addition amount of boron nitride in the polymer higher, and thus obtain higher thermal conductivity performance.

[0046] The modified boron nitride SM-BN has better compatibility with rubber, plastic and resin, and can effectively improve the mechanical properties and electrical properties of the insulation material. The addition of the coupling agent A172 can further reduce the surface polarity of boron nitride and improve the compatibility with the matrix material.

[0047] In the above formula, the present invention selects LDPE, which has a relatively high thermal conductivity among polymers and has good compatibility with EPM, as the second matrix. Its thermal conductivity is about 0.3W / (m·k), while the thermal conductivity of conventional EPDM is about 0.15W / (m·k). Because the thermal conductivity of conventional clay used in the prior art is less than 1W·(m·k) -1 , and cannot improve the thermal conductivity of the insulating material. The present invention creatively selects two boron nitrides with different structures as the second and third reinforcing filling materials, and their thermal conductivity reaches 300W·(m·k) -1 The modified boron nitride has better compatibility and reinforcement with EPM, while the spherical boron nitride mainly plays the role of filling and improving the fluidity of the material. With the coupling agent A172, it has good mechanical properties in the system. When there is no boron nitride in the formula system, the 95mm 2 Taking the cable as an example, the current carrying capacity is 278A when the conductor temperature is 90°C. When the insulating material of the present invention is used, the current carrying capacity of the conductor is 325A at 90°C, which indicates that the insulating material of the present invention can greatly improve the thermal conductivity of the insulating material and extend the service life of the insulation.

[0048] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0049] The spherical boron nitride and modified boron nitride used in the following examples were purchased from Suzhou Napu Material Technology Co., Ltd.

[0050] The specifications of spherical boron nitride are as follows:

[0051]

[0052] The specifications of modified boron nitride are as follows:

[0053]

[0054] Modified kaolin was purchased from Shanxi Xinjingtai Technology Co., Ltd. The product information is as follows:

[0055] PH value: 6 Particle size: -2μm; Density: 2.6g / cm 3 ; Screen residue ≤ 325%; Moisture content ≤ 0.5%

[0056] Type: Calcined kaolin; Model: XJT-S1.

[0057] Example 1

[0058] The cable insulation material formula has the following proportions: 72260 parts of EPM, 40 parts of LDPE, 10 parts of zinc oxide, 1 part of stearic acid, 3 parts of microcrystalline wax, 20 parts of spherical boron nitride S-BN, 10 parts of modified boron nitride SM-BN, 40 parts of modified kaolin, 2 parts of antioxidant, 1 part of coupling agent A172, 10 parts of paraffin oil, 2 parts of vulcanizing agent BIBP, and 1.5 parts of co-crosslinking agent TAIC. The insulation core is produced by a three-layer co-extrusion method. The cable voltage grade is 6 / 10 kV, the insulation thickness is 3.5 mm, 4 high-flexibility optical fibers are arranged at the center of the special-shaped support, and three groups of communication lines wrapped with winding ground wires are arranged at the edge gap of the cable core. The relevant performance parameters of the obtained cable are shown in Table 1.

[0059] Example 2

[0060] The cable insulation material formula has the following proportions: 72270 parts of EPM, 30 parts of LDPE, 15 parts of zinc oxide, 2 parts of stearic acid, 4.5 parts of microcrystalline wax, 15 parts of spherical boron nitride S-BN, 15 parts of modified boron nitride SM-BN, 30 parts of modified kaolin, 3 parts of antioxidant, 1.5 parts of coupling agent A172, 15 parts of paraffin oil, 2.5 parts of vulcanizing agent BIBP, and 1 part of co-crosslinking agent TAIC. The insulation core is produced by a three-layer co-extrusion method. The cable voltage grade is 8.7 / 10 kV, the insulation thickness is 4.0 mm, 6 high-flexibility optical fibers are arranged at the center of the special-shaped support, and three groups of communication lines wrapped with winding ground wires are arranged at the edge gap of the cable core. The relevant performance parameters of the obtained cable are shown in Table 1.

[0061] Example 3

[0062] The cable insulation material formula has the following proportions: 72280 parts of EPM, 20 parts of LDPE, 20 parts of zinc oxide, 3 parts of stearic acid, 6 parts of microcrystalline wax, 10 parts of spherical boron nitride S-BN, 20 parts of modified boron nitride SM-BN, 20 parts of modified kaolin, 4 parts of antioxidant, 2 parts of coupling agent A172, 20 parts of paraffin oil, 3 parts of vulcanizing agent BIBP, and 0.5 parts of co-crosslinking agent TAIC. The insulation core is produced by a three-layer co-extrusion method. The cable voltage grade is 8.7 / 15 kV, the insulation thickness is 4.5 mm, 12 high-flexibility optical fibers are arranged at the center of the special-shaped support, and three groups of communication lines wrapped with winding ground wires are arranged at the edge gap of the cable core. The relevant performance parameters of the obtained cable are shown in Table 1.

[0063] Comparative Example

[0064] The cable insulation material formula has the following proportions: 100 parts of EPM 722, 5 parts of zinc oxide, 3 parts of stearic acid, 6 parts of microcrystalline wax, 100 parts of talcum powder, 30 parts of modified kaolin, 4 parts of antioxidant, 2 parts of coupling agent A172, 10 parts of paraffin oil, 3 parts of vulcanizing agent BIBP, and 0.5 parts of co-crosslinking agent TAIC. The production of the insulated wire core is completed by a three-layer co-extrusion method. Only a metal / fiber hybrid braided layer is arranged outside the wire core according to the requirements of MT818. The cable voltage grade is 8.7 / 15 kV, the insulation thickness is 4.5 mm, 12 high-flexibility optical fibers are arranged at the center of the special-shaped support, and three groups of ordinary control wires are arranged at the edge gap of the cable core. The relevant performance parameters of the obtained cable are shown in Table 1.

[0065] Table 1. Relevant parameters of the cables in each embodiment

[0066]

[0067] Note: The current-carrying capacity comparison is to test and record the conductor surface temperature under a current of 278 A.

[0068] It can be seen from the data in Table 1 that compared with the comparative example, the shielding attenuation of the three embodiments is significantly improved, and the transfer impedance is greatly reduced, indicating that the cable shielding structure designed by the present invention achieves a good anti-interference effect and is conducive to the safer and more stable transmission of signals. Compared with the comparative example, when the three embodiments carry the same current, the temperature rise of the conductor is reduced by about 25 °C, indicating that the insulating layer of the present invention has a better heat dissipation effect. At the same time, the lower temperature can ensure that the insulation always remains at a relatively high insulation resistance level, ensuring that it can work continuously and stably under the high-voltage state of the insulation layer.

[0069] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

Claims

1. A cable insulating material for a coal mining machine with a voltage of 6 - 15 kV, characterized in that, It comprises the following raw materials in parts by weight: 60 - 80 parts of EPM, 20 - 40 parts of LDPE, 10 - 20 parts of zinc oxide, 1 - 3 parts of stearic acid, 3 - 6 parts of microcrystalline wax, 10 - 20 parts of spherical boron nitride, 10 - 20 parts of modified boron nitride, 20 - 40 parts of modified kaolin, 2 - 4 parts of antioxidant, 1 - 2 parts of coupling agent, 10 - 20 parts of paraffin oil, 2 - 3 parts of vulcanizing agent, 0.5 - 1.5 parts of co - crosslinking agent.

2. The cable insulating material for 6 - 15 kV coal mining machinery according to claim 1, characterized in that, The antioxidant is selected from at least one of 1010, MB, and RD; the coupling agent is selected from at least one of silane coupling agent KH550 and A172; the vulcanizing agent is selected from at least one of BIBP and DCP; the co - crosslinking agent is selected from at least one of TAIC and PL400.

3. The cable insulating material for 6 - 15 kV coal mining machinery according to claim 1 or 2, characterized in that, It comprises the following raw materials in parts by weight: 72 parts of EPM, 20 parts of LDPE, 20 parts of zinc oxide, 3 parts of stearic acid, 6 parts of microcrystalline wax, 10 parts of spherical boron nitride, 20 parts of modified boron nitride, 20 parts of modified kaolin, 4 parts of antioxidant, 2 parts of coupling agent, 20 parts of paraffin oil, 3 parts of vulcanizing agent, 0.5 parts of co - crosslinking agent.

4. A cable for coal mining machinery with a voltage of 6 - 15 kV, characterized in that, It includes a cable core and a sheath layer covering the cable core. The cable core is stranded by three power cores (2) and three groups of communication cores (1) around a central special - shaped support (3); the center of the special - shaped support (3) contains multiple optical fibers (4); The power core (2) comprises an insulated core and a composite shielding layer (25). The insulated core is formed by co - extruding three layers of a power conductor (21), a conductor shielding layer (22), an insulating layer (23), and an insulation shielding layer (24). The composite shielding layer (25) is wound around the outside of the insulation shielding layer (24), and the insulating layer (23) is made of the cable insulating material described in claim 1.

5. A cable for 6 - 15 kV coal mining machinery according to claim 4, characterized in that, The composite shielding layer (25) comprises a copper foil wound around the insulation shielding layer (24), a metal braided layer outside the copper foil, and an aluminum foil wound around the metal braided layer.

6. The cable for coal mining machinery with a voltage of 6 - 15 kV according to claim 5, characterized in that, The overlapping rates of the copper foil and the aluminum foil winding are both greater than 20% and less than or equal to 50%.

7. A cable for 6 - 15 kV coal mining machinery according to claim 4, characterized in that, The communication core (1) comprises a communication conductor (14), a communication insulating layer (15), a communication sheath layer (13), a ground conductor (12), and a ground semi - conductive adhesive (11) arranged from the inside out. The ground conductor (12) is spirally wound around the outside of the communication sheath layer (13).

8. A cable for 6 - 15 kV coal mining machinery according to claim 7, characterized in that, The covering density of the spiral winding of the ground conductor (12) is greater than 85% and less than or equal to 100%.

9. A cable for 6 - 15 kV coal mining machinery according to claim 4, characterized in that, The center of the special - shaped support (3) contains 4 - 12 high - flexible optical fibers (4).

10. A cable for 6 - 15 kV coal mining machinery according to claim 4, characterized in that, The sheath layer comprises an inner sheath (51), a fiber braided strengthening layer (52), and an outer sheath (53) arranged from the inside out.

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