A medium voltage feeder cable and its preparation method and application

Abstract

The present invention provides a medium-voltage feeder cable and a preparation method and application thereof. The medium-voltage feeder cable comprises a core conductor, a conductor shielding layer, an insulating layer, an insulating shielding layer, a copper wire shielding layer and an outer sheath which are stacked in sequence from the inside to the outside; the core conductor has a structure of 1+6+12+18+24; each of the 24 conductors in the outermost layer of the core conductor independently comprises a conductive monofilament and a reinforcing wire. The present invention designs the structure of the medium-voltage feeder cable and further designs the core conductor structure of the medium-voltage feeder cable, so that each of the 24 conductors in the outermost layer of the core conductor independently comprises a conductive monofilament and a reinforcing wire, thereby preparing a medium-voltage feeder cable which meets the requirements of a withstand voltage of 35kV, a voltage drop of 5V / m, a temperature rise not exceeding 100K / 10s, and a cable outer diameter of ≤42mm, while having a low conductor resistance and a low conductor broken wire rate.

Description

Technical Field

[0001] The invention belongs to the technical field of cables, and in particular relates to a medium voltage feeder cable and a preparation method and application thereof. Background Art

[0002] The high-speed railway maglev system has many advantages such as contactless operation, high speed, fast start-up, low energy consumption, and small environmental impact. As a new type of transportation, maglev transportation is a high-tech transportation tool that uses the attraction and repulsion between magnetic poles. It mainly relies on electromagnetic force to achieve the support, guidance, traction and braking functions of traditional railways. This electromagnetic force will generate a strong electromagnetic field, which will cause strong electromagnetic interference to the surrounding environment.

[0003] The special cable for magnetic levitation is a special flexible medium voltage cable designed and manufactured for the magnetic levitation system, with a rated voltage of 10 / 17.5 (20) kV and a frequency range of 0 to 50 Hz. Since it works in a variable frequency strong magnetic field, it is usually laid outdoors along the tracks on both sides. The cable not only has extremely high flexibility requirements, but also must have weather resistance, corrosion resistance, flame retardancy and self-lubrication. Therefore, high requirements are placed on the mechanical, electrical and environmental resistance properties of the cable structure, insulation and sheath materials.

[0004] However, the conventional medium-voltage cables provided by the prior art have a ground voltage of 8.7kV or 12kV, and a withstand voltage of 30.5kV or 42kV respectively. However, these two types of cables cannot simultaneously meet the requirements of withstand voltage of 35kV, voltage drop of 5V / m, temperature rise not exceeding 100K / 10s, and cable outer diameter ≤42mm. In addition, the conductor breakage rate is high after repeated bending of the cable, and the effect is not ideal when applied to high-speed magnetic levitation systems.

[0005] Therefore, how to provide a medium-voltage feeder cable that meets the requirements of 35kV withstand voltage, 5V / m voltage drop, temperature rise not exceeding 100K / 10s, cable outer diameter ≤42mm, while having low conductor resistance (≤0.0659Ω / km) and low conductor breakage rate has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the deficiencies of the prior art, the object of the present invention is to provide a medium-voltage feeder cable and a preparation method and application thereof. The present invention designs the structure of the medium-voltage feeder cable, and further designs the core conductor structure of the medium-voltage feeder cable, so that each of the outermost 24 conductors of the core conductor independently includes a conductive monofilament and a reinforcing wire, thereby preparing a medium-voltage feeder cable that meets the requirements of 35kV withstand voltage, 5V / m voltage drop, temperature rise not exceeding 100K / 10s, and cable outer diameter ≤42mm, while having a low conductor resistance (≤0.0659Ω / km) and a low conductor broken wire rate.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a medium voltage feeder cable, wherein the medium voltage feeder cable comprises, from the inside to the outside, a core conductor, a conductor shielding layer, an insulating layer, an insulating shielding layer, a copper wire shielding layer and an outer sheath which are stacked in sequence;

[0009] The core conductor has a structure of 1+6+12+18+24;

[0010] Each of the 24 outermost conductors of the battery core conductors independently comprises a conductive monofilament and a reinforcing wire.

[0011] The present invention designs the structure of a medium-voltage feeder cable and further designs the core conductor structure of the medium-voltage feeder cable, so that each of the outermost 24 conductors of the core conductor independently includes a conductive monofilament and a reinforcing wire, thereby preparing a medium-voltage feeder cable that meets the requirements of a withstand voltage of 35 kV, a voltage drop of 5 V / m, a temperature rise not exceeding 100 K / 10 s, and a cable outer diameter of ≤42 mm, while having a low conductor resistance (≤0.0659 Ω / km) and a low conductor broken wire rate.

[0012] In the present invention, each of the outermost 24 conductors of the core conductor is designed to independently include a conductive monofilament and a reinforcing wire, so as to prepare a medium-voltage feeder cable with low conductor resistance and low conductor wire breakage rate. If each conductor of the core conductor is provided with a conductive monofilament and a reinforcing wire, the conductor outer diameter of the prepared medium-voltage feeder cable is large, the resistance is high, and the conductor wire breakage rate will not be further reduced.

[0013] In the present invention, the structure of the battery core conductor being 1+6+12+18+24 means that 6 conductors are arranged on the outer surface of the conductor at the center of the battery core conductor, 12 conductors are arranged on the outer surface of the 6 conductors, 18 conductors are arranged on the outer surface of the 12 conductors, and 24 conductors are arranged on the outer surface of the 18 conductors.

[0014] The present invention has no limitation on the preparation method of the battery core conductor having a structure of 1+6+12+18+24. The commonly used preparation methods in the art are applicable. The preparation method can be prepared by referring to the cable conductor twisting method provided in CN104091654A, which includes but is not limited to twisting. The twisting method includes the following steps:

[0015] S1: Cable core traction device; one end of the cable core is fixedly connected to the traction device of the production line for stranding large-section cables, and 6 conductors are stranded on the central conductor to form a 1+6 structure conductor;

[0016] S2: Twisting the 12 conductors of the second layer; first prepare 12 conductors, and then twist the 12 conductors on the conductors of the 1+6 structure in the 12-reel twisting cage of the large-section cable production line to form a conductor of the 1+6+12 structure;

[0017] S3: Stranding 18 conductors of the third layer; first prepare 18 conductors, then through the pulling action of the tension traction wheel, pass the stranded 1+6+12 structure conductors through the 18-drum stranding cage of the production line of the large-section cable, and strand the 18 conductors on the 1+6+12 structure conductors to form a 1+6+12+18 structure conductor;

[0018] S4: stranding 24 conductors of the fourth layer; first prepare 24 conductors, and then through the pulling action of the tension traction wheel, pass the stranded 1+6+12+18 structure conductors through the 24-drum stranding cage of the production line of the large-section cable, and strand the 24 conductors on the 1+6+12+18 structure conductor to obtain a core conductor with a 1+6+12+18+24 structure.

[0019] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0020] As a preferred technical solution of the present invention, among the outermost 24 conductors of the battery core conductor, each conductor independently includes 38-42 (for example, 38, 39, 40, 41 or 42) conductive monofilaments and 8-12 (for example, 8, 9, 10, 11 or 12) reinforcing wires.

[0021] The present invention controls the number of reinforcing wires in each of the outermost 24 conductors of the core conductor within a specific range, thereby preparing a core conductor with both low resistance and low wire breakage rate. If the number of reinforcing wires in each of the outermost 24 conductors is too small, the prepared core conductor has a high wire breakage rate; if the number of reinforcing wires in each of the outermost 24 conductors is too large, the prepared core conductor has a high resistance.

[0022] The present invention controls the number of conductive monofilaments and reinforcing wires of each conductor in the outermost 24 conductors of the core conductor within a specific range, thereby preparing a core conductor with a diameter within a specific range, and further preparing a medium-voltage feeder cable that meets the requirements of a withstand voltage of 35 kV, a voltage drop of 5 V / m, a temperature rise not exceeding 100 K / 10s, and a cable outer diameter of ≤42 mm.

[0023] As a preferred technical solution of the present invention, the fineness of the reinforcing wire is ≥1500D, for example, it can be 1500D, 1610D or 1670D.

[0024] The present invention controls the fineness of the reinforcing wire within a specific range to prepare a medium-voltage feeder cable with excellent comprehensive performance. If the fineness of the reinforcing wire is too small, the wire breakage rate of the prepared medium-voltage feeder cable cannot be effectively reduced; if the fineness of the reinforcing wire is too large, the outer diameter of the prepared medium-voltage feeder cable is too large, the resistance is too large, and the cost is increased without significantly improving the wire breakage rate.

[0025] Preferably, the fineness of the conductive monofilament is 0.398-0.401 mm, for example, it can be 0.398 mm, 0.399 mm, 0.400 mm or 0.401 mm.

[0026] As a preferred technical solution of the present invention, the reinforcing yarn is selected from aramid yarn.

[0027] The present invention prepares a medium-voltage feeder cable with excellent comprehensive performance by using specific reinforcing wires.

[0028] Based on cost considerations, aramid yarn is preferred as the reinforcing yarn.

[0029] Preferably, the conductive monofilaments include tinned copper wires.

[0030] As a preferred technical solution of the present invention, except for the outermost 24 conductors of the battery core conductor, the other conductors independently include 38-42 (for example, 38, 39, 40, 41 or 42) conductive monofilaments;

[0031] The conductive monofilament comprises a tinned copper wire;

[0032] The fineness of the conductive monofilament is 0.398-0.401 mm, for example, it can be 0.398 mm, 0.399 mm, 0.400 mm or 0.401 mm.

[0033] As a preferred technical solution of the present invention, the diameter of the battery core conductor is 23.5-24.5 mm, for example, it can be 23.5 mm, 23.6 mm, 23.7 mm, 23.8 mm, 23.9 mm, 24.0 mm, 24.1 mm, 24.2 mm, 24.3 mm, 24.4 mm or 24.5 mm.

[0034] As a preferred technical solution of the present invention, the thickness of the conductor shielding layer is 0.3-0.5 mm, for example, it can be 0.3 mm, 0.32 mm, 0.34 mm, 0.36 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm or 0.5 mm.

[0035] Preferably, the material of the conductor shielding layer comprises semiconductor extrusion material or semiconductor electrical wrapping tape.

[0036] As a preferred technical solution of the present invention, the thickness of the insulating layer is 3.44-4.2 mm, for example, it can be 3.44 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4.0 mm, 4.1 mm or 4.2 mm.

[0037] Preferably, the material of the insulating layer includes an ethylene-propylene rubber composition.

[0038] Preferably, the EPDM rubber composition comprises the following components in parts by weight: 40-60 parts of EPDM rubber, 8-12 parts of low-density polyethylene resin, 40-60 parts of modified calcined kaolin, 2-3 parts of zinc oxide, 3-4 parts of microcrystalline wax, 0.8-1.2 parts of titanium dioxide and 3-5 parts of paraffin oil.

[0039] In the present invention, the EPDM rubber in the EPDM rubber composition may be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts or 60 parts.

[0040] The low-density polyethylene resin in the EPDM rubber composition can be 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, 10.5 parts, 11 parts, 11.5 parts or 12 parts.

[0041] The modified calcined kaolin in the EPDM rubber composition may be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts or 60 parts, etc.

[0042] The zinc oxide in the EPDM rubber composition can be 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts or 3 parts.

[0043] The microcrystalline wax in the EPDM rubber composition can be 3 parts, 3.1 parts, 3.2 parts, 3.3 parts, 3.4 parts, 3.5 parts, 3.6 parts, 3.7 parts, 3.8 parts, 3.9 parts or 4 parts.

[0044] The titanium dioxide in the EPDM rubber composition may be 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, 1 parts, 1.05 parts, 1.1 parts, 1.15 parts or 1.2 parts.

[0045] The paraffin oil in the EPDM rubber composition can be 3 parts, 3.2 parts, 3.4 parts, 3.6 parts, 3.8 parts, 4 parts, 4.2 parts, 4.4 parts, 4.6 parts, 4.8 parts or 5 parts.

[0046] The EPDM rubber composition further comprises any one or a combination of at least two of an antioxidant, an antioxidant synergist, a coupling agent, a crosslinking agent or a crosslinking aid;

[0047] Preferably, the content of the antioxidant in the EPDM rubber composition is 0.3 to 0.7 parts by weight, for example, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight or 0.7 parts by weight.

[0048] Preferably, the content of the antioxidant synergist in the EPDM rubber composition is 0.3 to 0.7 parts by weight, for example, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight or 0.7 parts by weight.

[0049] Preferably, the content of the coupling agent in the EPDM rubber composition is 0.3 to 0.7 parts by weight, for example, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight or 0.7 parts by weight.

[0050] Preferably, the content of the crosslinking agent in the EPDM rubber composition is 1 to 3 parts by weight, for example, it can be 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight or 3 parts by weight, etc.

[0051] Preferably, the content of the crosslinking aid in the EPDM rubber composition is 0.3 to 0.7 parts by weight, for example, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight or 0.7 parts by weight.

[0052] As a preferred technical solution of the present invention, the thickness of the insulating shielding layer is 0.3-0.5 mm, for example, it can be 0.3 mm, 0.32 mm, 0.34 mm, 0.36 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm or 0.5 mm.

[0053] Preferably, the insulating shielding layer is made of semiconductor material.

[0054] Preferably, the semiconductor material comprises a semiconductor extruded material or a semiconductor electrical wrapping tape.

[0055] As a preferred technical solution of the present invention, the material of the copper wire shielding layer is tinned copper wire.

[0056] Preferably, the single wire diameter of the tinned copper wire is 0.2-0.25 mm, for example, it can be 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm or 0.25 mm.

[0057] As a preferred technical solution of the present invention, the thickness of the outer sheath is 1.8-2.2 mm, for example, it can be 1.8 mm, 1.85 mm, 1.9 mm, 2 mm, 2.05 mm, 2.1 mm, 2.15 mm or 2.2 mm.

[0058] Preferably, the outer sheath is a low-smoke halogen-free elastomer sheath.

[0059] In a second aspect, the present invention provides a method for preparing a medium voltage feeder cable as described in the first aspect, the method comprising the following steps:

[0060] (1) extruding the materials of the conductor shielding layer, the insulating layer and the insulating shielding layer sequentially on the surface of the battery core conductor to obtain a composite layer;

[0061] (2) The material of the copper wire shielding layer is woven onto the outer surface of the composite layer and connected to the outer sheath to obtain the medium voltage feeder cable.

[0062] In a third aspect, the present invention provides an application of the medium voltage feeder cable as described in the first aspect in high-speed maglev.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] The present invention designs the structure of a medium-voltage feeder cable and further designs the core conductor structure of the medium-voltage feeder cable, so that each of the outermost 24 conductors of the core conductor independently includes a conductive monofilament and a reinforcing wire, and the amount and fineness of the reinforcing wire are controlled within a specific range. A medium-voltage feeder cable is prepared which meets the requirements of a withstand voltage of 35 kV, a voltage drop of 5 V / m, a temperature rise not exceeding 100 K / 10 s, and a cable outer diameter of ≤42 mm, while having a low conductor resistance (≤0.0659 Ω / km) and a low conductor broken wire rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 is a schematic structural diagram of a medium voltage feeder cable provided in Embodiment 1 of the present invention;

[0066] Figure 2 It is a schematic structural diagram of a core conductor in a medium voltage feeder cable provided in Embodiment 1 of the present invention;

[0067] Among them, 1-core conductor, 2-conductor shielding layer, 3-insulating layer, 4-insulating shielding layer, 5-copper wire shielding layer, 6-outer sheath. DETAILED DESCRIPTION

[0068] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0069] The sources of some components in the following examples and comparative examples are as follows:

[0070] The material of the insulating layer is an ethylene-propylene rubber composition, and the specific composition is referred to Preparation Example 1 of CN113793729A.

[0071] Example 1

[0072] This embodiment provides a medium voltage feeder cable and a preparation method thereof. The structural schematic diagram of the medium voltage feeder cable is shown in FIG. Figure 1 As shown, from the inside to the outside, it includes a core conductor 1, a conductor shielding layer 2, an insulating layer 3, an insulating shielding layer 4, a copper wire shielding layer 5 and an outer sheath 6 which are stacked in sequence;

[0073] The structural schematic diagram of the battery core conductor 1 is as follows Figure 2 As shown, it has a structure of 1+6+12+18+24 and a diameter of 24.0 mm;

[0074] Each of the 24 outermost conductors of the battery core conductor 1 includes 39 tinned copper wires (fineness is 0.399 mm) and 10 aramid wires (each aramid wire has a fineness of 0.30 mm after twisting, purchased from Taihe New Materials, brand aramid, 1500D), except for the 24 outermost conductors, the other conductors each independently include 39 tinned copper wires (fineness is 0.399 mm), which are prepared by a twisting method;

[0075] The conductor shielding layer 2 has a thickness of 0.4 mm and is made of peroxide cross-linked semiconductor material for EPDM insulated cables (purchased from Shandong Zhanxin New Materials Co., Ltd., with a brand name of PEJD).

[0076] The thickness of the insulating layer 3 is 3.8 mm, and the material is an ethylene-propylene rubber composition;

[0077] The thickness of the insulating shielding layer 4 is 0.5 mm, and the material is a peroxide cross-linked semiconductor material for conductive EPDM insulated cables (purchased from Shandong Zhanxin New Materials Co., Ltd., brand PEJD);

[0078] The single wire diameter of the copper wire shielding layer 5 is 0.2 mm, and the material is tinned copper wire;

[0079] The thickness of the outer sheath 6 is 2.0 mm, and the material is low-smoke halogen-free elastomer (purchased from Mafu Rubber & Plastic (Zhenjiang) Co., Ltd., brand LSOH-90).

[0080] The preparation method of the above medium voltage feeder cable is as follows:

[0081] (1) extruding the materials of the conductor shielding layer, the insulating layer and the insulating shielding layer sequentially on the surface of the battery core conductor to obtain a composite layer;

[0082] (2) The material of the copper wire shielding layer is woven onto the outer surface of the composite layer and connected to the outer sheath to obtain the medium voltage feeder cable.

[0083] Example 2

[0084] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0085] The diameter of the core conductor is 24.5 mm; each of the outermost 24 conductors of the core conductor independently includes 42 tinned copper wires (fineness is 0.398 mm) and 10 twisted aramid wires (the fineness of each aramid wire after twisting is 0.33 mm, purchased from Taihe New Materials, brand aramid, 1610D), and except for the outermost 24 conductors, the other conductors independently include 42 tinned copper wires (fineness is 0.398 mm), which are prepared by a twisting method;

[0086] The thickness of the conductor shielding layer is 0.5 mm;

[0087] The thickness of the insulation layer is 4.2mm;

[0088] The thickness of the insulation shielding layer is 0.4mm;

[0089] The single wire diameter of the copper wire shield is 0.25mm;

[0090] The thickness of the outer sheath is 2.2mm;

[0091] Other conditions are the same as in Example 1.

[0092] Example 3

[0093] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0094] The diameter of the core conductor is 24.3 mm; each of the outermost 24 conductors of the core conductor independently includes 40 tinned copper wires (fineness is 0.401) and 11 aramid wires (the fineness of each aramid wire after twisting is 0.30 mm, purchased from Taihe New Materials, brand aramid, 1500D), except for the outermost 24 conductors, the other conductors independently include 40 tinned copper wires (fineness is 0.401 mm), which are prepared by a twisting method;

[0095] The thickness of the conductor shielding layer is 0.3 mm;

[0096] The thickness of the insulation layer is 3.5mm;

[0097] The thickness of the insulation shielding layer is 0.3mm;

[0098] The single wire diameter of the copper wire shield is 0.23mm;

[0099] The thickness of the outer sheath is 1.8mm;

[0100] Other conditions are the same as in Example 1.

[0101] Example 4

[0102] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0103] The diameter of the battery core conductor is 24.0 mm;

[0104] Each of the outermost 24 conductors of the core conductor is independently wrapped with 39 tinned copper wires (fineness is 0.399 mm) and 8 aramid wires (each aramid wire has a fineness of 0.30 mm after twisting, purchased from Taihe New Materials, brand aramid, 1500D)

[0105] Other conditions are the same as in Example 1.

[0106] Example 5

[0107] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0108] The diameter of the battery core conductor is 24.0 mm;

[0109] Each of the outermost 24 conductors of the core conductor is independently wrapped with 39 tinned copper wires (fineness is 0.399 mm) and 12 aramid wires (each aramid wire has a fineness of 0.30 mm after twisting, purchased from Taihe New Materials, brand aramid, 1500D)

[0110] Other conditions are the same as in Example 1.

[0111] Example 6

[0112] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0113] The diameter of the battery core conductor is 24.0 mm;

[0114] Each of the outermost 24 conductors of the core conductor is independently wrapped with 39 tinned copper wires (fineness is 0.399 mm) and 7 aramid wires (each aramid wire has a fineness of 0.30 mm after twisting, purchased from Taihe New Materials, brand aramid, 1500D)

[0115] Other conditions are the same as in Example 1.

[0116] Example 7

[0117] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0118] The diameter of the battery core conductor is 24.0 mm;

[0119] Each of the outermost 24 conductors of the core conductor is independently wrapped with 39 tinned copper wires (fineness is 0.399 mm) and 14 aramid wires (each aramid wire has a fineness of 0.30 mm after twisting, purchased from Taihe New Materials, brand aramid, 1500D)

[0120] Other conditions are the same as in Example 1.

[0121] Example 8

[0122] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0123] The diameter of the battery core conductor is 24.0 mm;

[0124] Each of the outermost 24 conductors of the core conductor is independently wrapped with 39 tinned copper wires (fineness is 0.399 mm) and 12 aramid yarns (each aramid yarn has a fineness of 0.33 mm after twisting, purchased from Taihe New Materials, brand aramid, 1610D)

[0125] Other conditions are the same as in Example 1.

[0126] Example 9

[0127] This embodiment provides a medium voltage feeder cable and a preparation method thereof, which is different from Embodiment 1 only in that;

[0128] The diameter of the battery core conductor is 24.0 mm;

[0129] Each of the outermost 24 conductors of the core conductor is independently wrapped with 39 tinned copper wires (fineness is 0.399 mm) and 12 aramid yarns (each aramid yarn has a fineness of 0.2 mm after twisting, purchased from Taihe New Materials, brand aramid, 1100D)

[0130] Other conditions are the same as in Example 1.

[0131] Comparative Example 1

[0132] This comparative example provides a medium voltage feeder cable and a preparation method thereof, which differs from Example 1 only in that;

[0133] The diameter of the battery core conductor is 23.5 mm;

[0134] The outermost 24 conductors of the battery core conductor do not include aramid wires, and each conductor is composed of 46 tinned copper wires (fineness is 0.399 mm). Except for the outermost 24 conductors, the other conductors each independently include 42 tinned copper wires (fineness is 0.399 mm), which are prepared by a twisting method;

[0135] Other conditions are the same as in Example 1.

[0136] Comparative Example 2

[0137] This comparative example provides a medium voltage feeder cable and a preparation method thereof, which differs from Example 1 only in that;

[0138] The core conductor 1 has a structure of 1+6+12+18+24, and each of the 61 conductors of the core conductor includes 39 tinned copper wires (fineness is 0.399 mm) and 10 aramid wires (the fineness of each aramid wire after twisting is 0.2 mm, purchased from Taihe New Materials, brand aramid, 1100D);

[0139] Other conditions are the same as in Example 1.

[0140] Comparative Example 3

[0141] This comparative example provides a medium voltage feeder cable and a preparation method thereof, which differs from Example 1 only in that;

[0142] The core conductor has a structure of 1+6+12+18+24 and a diameter of 24.2 mm;

[0143] Among the 18 conductors of the secondary outer layer of the battery core conductor, each conductor includes 39 tinned copper wires (fineness is 0.399 mm) and 10 aramid wires (each aramid wire has a fineness of 0.2 mm after twisting, purchased from Taihe New Materials, brand aramid, 1100D), except for the 18 conductors of the secondary outer layer, the other conductors each independently include 39 tinned copper wires (fineness is 0.399 mm), which are prepared by a twisting method;

[0144] Other conditions are the same as in Example 1.

[0145] The performance of the medium voltage feeder cables provided in the above embodiments and comparative examples was tested, and the specific testing method is as follows:

[0146] (1) Withstand voltage: Tested in accordance with the test method provided in GB / T 3048.8;

[0147] (2) Voltage drop: Connect the tested cable to a three-phase variable frequency adjustable AC power supply in a three-phase star connection. Adjust the output current of the three-phase variable frequency adjustable AC power supply to I, the output voltage to U, the cable test length to L, the cable impedance Z = U / I / L, and △U (voltage drop) = Z × 5000;

[0148] (3) Temperature rise: Connect the tested cable to the variable frequency AC power supply circuit through a switch, adjust the output current of the variable frequency AC power supply, continuously energize the tested cable, and record the temperature of the key parts of the cable conductor. When the temperature rises by 10K, record the time it takes to reach the corresponding temperature. The test ends when the temperature of the internal conductor of the cable rises to 100K or the temperature stops rising.

[0149] (4) Flame retardant: Tested in accordance with the test method provided in GB / T 12706.2.

[0150] (5) Broken wire rate of core conductor: The test is carried out according to the torsion test method provided in GB / T 33606. After the test, the broken wire rate is calculated as the number of broken wires / total number of wires × 100%;

[0151] (6) Core conductor resistance: Tested according to the test method provided in GB / T 3048.4;

[0152] (7) Cell conductor resistance margin: (measured resistance / standard resistance-1)*100%.

[0153] The above performance test results are shown in Table 1 below:

[0154] Table 1

[0155]

[0156] It can be seen from the above content that the present invention designs the structure of the medium-voltage feeder cable, and further designs the core conductor structure of the medium-voltage feeder cable, so that each of the outermost 24 conductors of the core conductor independently includes a conductive monofilament and a reinforcing wire, and prepares a medium-voltage feeder cable that meets the requirements of withstand voltage 35kV / 5min, voltage drop ≤5V / m, specifically 4.3-4.9V / m, temperature rise of no more than 100K / 10s, specifically 29-37K / 10s, and cable outer diameter ≤42mm, while the core conductor resistance is ≤0.0659Ω / km, specifically 0.0604-0.0655Ω / km, the margin is -0.6--8.4%, and the conductor broken wire rate is ≤2.1%, specifically 1.1-2.1%.

[0157] It can be seen from Examples 1 and 4-9 that the present invention further optimizes the comprehensive performance of the medium voltage feeder cable by designing the number and fineness of the reinforcing wires in the outermost 24 conductors of the core conductor, and the core conductor resistance is ≤0.0652Ω / km, specifically 0.0604-0.0652Ω / km, the margin is -1.1 to -8.4%, and the conductor broken wire rate is ≤1.9%, specifically 1.1-1.9% of the medium voltage feeder cable.

[0158] It can be seen from Example 1 and Comparative Examples 1-3 that the present invention designs the structure of the medium-voltage feeder cable, and further designs the core conductor structure of the medium-voltage feeder cable, so that each of the outermost 24 conductors of the core conductor independently includes a conductive monofilament and a reinforcing wire, thereby preparing a medium-voltage feeder cable with excellent comprehensive performance.

[0159] In summary, the present invention designs the structure of a medium-voltage feeder cable, and further designs the core conductor structure of the medium-voltage feeder cable, so that each of the outermost 24 conductors of the core conductor independently includes a conductive monofilament and a reinforcing wire, and the amount and fineness of the reinforcing wire are controlled within a specific range, thereby preparing a medium-voltage feeder cable with excellent comprehensive performance.

[0160] The applicant declares that the present invention illustrates the detailed structural features and detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features and detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features and detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of the components selected by the present invention, the addition of auxiliary components, the selection of specific methods, etc., the equivalent replacement of the raw materials of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A medium voltage feeder cable, characterized in that: The medium voltage feeder cable comprises, from the inside to the outside, a core conductor, a conductor shielding layer, an insulating layer, an insulating shielding layer, a copper wire shielding layer and an outer sheath which are stacked in sequence; The core conductor has a structure of 1+6+12+18+24; Each of the outermost 24 conductors of the battery core conductor independently comprises a conductive monofilament and a reinforcing wire.

2. The medium voltage feeder cable according to claim 1, characterized in that: Among the outermost 24 conductors of the battery core conductor, each conductor independently includes 38-42 conductive monofilaments and 8-12 reinforcing wires.

3. The medium voltage feeder cable according to claim 2, characterized in that: The fineness of the reinforcing wire is ≥1500D; Preferably, the fineness of the conductive monofilament is 0.398-0.401 mm.

4. The medium voltage feeder cable according to any one of claims 1 to 3, characterized in that: The reinforcing yarn is selected from aramid yarn; Preferably, the conductive monofilaments include tinned copper wires.

5. The medium voltage feeder cable according to any one of claims 1 to 4, characterized in that: Except for the outermost 24 conductors, the other conductors of the battery core conductor independently include 38-42 conductive monofilaments; The conductive monofilament comprises a tinned copper wire; The fineness of the conductive monofilament is 0.398-0.401 mm.

6. The medium voltage feeder cable according to any one of claims 1 to 5, characterized in that: The diameter of the battery core conductor is 23.5-24.5 mm.

7. The medium voltage feeder cable according to any one of claims 1 to 6, characterized in that: The thickness of the conductor shielding layer is 0.3-0.5 mm; Preferably, the thickness of the insulating layer is 3.44-4.2 mm; Preferably, the thickness of the insulating shielding layer is 0.3-0.5 mm.

8. The medium voltage feeder cable according to any one of claims 1 to 7, characterized in that: The material of the copper wire shielding layer is tinned copper wire; Preferably, the single wire diameter of the tinned copper wire is 0.2-0.25 mm; Preferably, the thickness of the outer sheath is 1.8-2.2 mm.

9. A method for preparing a medium voltage feeder cable according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) extruding the materials of the conductor shielding layer, the insulating layer and the insulating shielding layer sequentially on the surface of the battery core conductor to obtain a composite layer; (2) The material of the copper wire shielding layer is woven onto the outer surface of the composite layer and connected to the outer sheath to obtain the medium voltage feeder cable.

10. Application of the medium voltage feeder cable according to any one of claims 1 to 8 in high-speed maglev.

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