Superconducting cable, method for preparing insulating layer on surface of superconducting cable and application

Abstract

The invention belongs to the technical field of superconducting cables, and relates to a superconducting cable, a method for preparing an insulating layer on the surface of the superconducting cable and application. The invention provides a superconducting cable which comprises a superconducting wire core and an insulating layer arranged on the surface of the superconducting wire core, and the insulating layer sequentially comprises a first spiral winding layer, a second spiral winding layer and a weaving layer from inside to outside; the direction of the first spiral winding layer is opposite to that of the second spiral winding layer. According to the superconducting cable provided by the invention, the bending resistance of the cable can be improved, and a certain compression strength can be maintained at a higher sintering temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of superconducting cables and relates to a superconducting cable and a method and application of preparing an insulating layer on the surface of a superconducting cable. Background Art

[0002] The structure of high-temperature superconducting cable can be mainly divided into supporting skeleton, superconducting layer, insulating layer, grounding layer (shielding layer) and protective layer from inside to outside. When air gap defects appear in the insulation layer of superconducting cable, the local discharge model can be regarded as the conductor layer discharging the insulating layer. According to the structure of the superconducting cable conductor, the mechanical structure of high-temperature superconducting cable is mainly divided into two forms: rigid cable and flexible cable. In rigid cable, the superconductor is arranged parallel to the axis of the rigid skeleton. The advantage is that the structure is simple and can avoid bending and causing the performance degradation of the superconducting tape; the disadvantage is that the thermal shrinkage caused by cooling from room temperature to liquid nitrogen temperature will bring adverse effects, especially when the cable is long, the thermal shrinkage may damage the entire cable. Flexible cable uses multi-core silver-sheathed superconducting tape to wind a multi-layer spiral structure with a fixed pitch on the supporting skeleton, and a certain narrow gap is left between the same layer of superconducting tape. This structure can avoid the adverse effects of thermal shrinkage, can be bent, and is suitable for winding longer cables to meet the needs of transportation and installation. The axial magnetic flux in the cable can also be offset by the different current winding directions between the layers of strips, reducing the degradation of the strip performance in the conductor layer. The existing commonly used cables are usually rigid cables, consisting of a conductive copper core and an outer insulating layer, and the outer insulating layer is mostly wrapped around the outside of the conductive copper core in the form of a multi-strand linear insulating material weaving method. However, under this cable structure, once the cable is bent, the warp and weft of the outer insulating layer will have gaps or breaks due to bending and stretching, thereby affecting the insulation effect and compressive strength of the entire cable. In addition, when preparing common superconducting cables (such as CN116598063A), the insulation layer is first twisted and then heat-treated, which effectively avoids the damage to the brittle superconducting phase caused by external forces such as bending, torsion, and shearing during subsequent use, ensuring the integrity of the multi-core subcomponent wires and the continuous and uniform distribution of the superconducting phase, thereby obtaining a high-performance superconducting cable. Due to the popularization of superconducting cable application scenarios, superconducting cables have to face more bending scenarios. However, after the insulation layer of superconducting cables is twisted and then heat treated, their bending resistance drops sharply, and the performance of superconducting cables is affected. Summary of the invention

[0003] The purpose of the present invention is to improve the structure of the insulation layer of a superconducting cable so that its bending resistance, especially the bending resistance after high-temperature sintering, is improved. To this end, the present invention provides a superconducting cable and a method and application for preparing an insulation layer on the surface of a superconducting cable to solve this need in the art.

[0004] In one aspect, the present invention relates to a superconducting cable, comprising a superconducting wire core and an insulating layer arranged on the surface of the superconducting wire core, wherein the insulating layer is a first spiral winding layer, a second spiral winding layer and a braided layer from inside to outside; The first helically wound layer is in an opposite direction to the second helically wound layer.

[0005] Furthermore, in the superconducting cable provided by the present invention, the first helically wound layer, the second helically wound layer or the braided layer are made of insulating fibers.

[0006] Furthermore, in the superconducting cable provided by the present invention, the insulating fiber is glass fiber and / or polyester fiber.

[0007] Furthermore, in the superconducting cable provided by the present invention, the thickness of the insulating layer is 0.1-0.2 mm.

[0008] On the other hand, the present invention relates to a method for preparing an insulating layer on the surface of a superconducting cable, which comprises: preparing the superconducting cable.

[0009] Furthermore, in the method for preparing an insulating layer on the surface of a superconducting cable provided by the present invention, it comprises: using N insulating fibers arranged in parallel to be spirally wound on the surface of the superconducting wire core along the center line of its axis in a first direction to prepare the first spirally wound layer; Using n parallelly arranged insulating fibers to spirally wind the first spirally wound layer along the center line of the axis toward a second direction to obtain the second spirally wound layer; installing the braided layer on the surface of the second spirally wound layer; The braided layer is woven by warp and weft in a staggered manner; The N or the n is independently selected from positive integers.

[0010] Specifically, the present invention does not particularly limit the angle of the first direction or the second direction, and the angle of the first direction or the second direction is independently selected from 30 to 60 degrees.

[0011] Furthermore, in the method for preparing an insulating layer on the surface of a superconducting cable provided by the present invention, the thickness of the braided layer is 0.03-0.08 mm.

[0012] Furthermore, in the method for preparing an insulating layer on the surface of a superconducting cable provided by the present invention, the spiral winding speed of the first spiral winding layer or the second spiral winding layer is independently selected from 150 to 300 turns / minute, and the spiral winding thickness is independently selected from 0.03 to 0.06 mm.

[0013] Furthermore, in the method for preparing an insulating layer on the surface of a superconducting cable provided by the present invention, the braiding pitch of the braided layer is 8 to 12 mm.

[0014] On the other hand, the present invention relates to the application of the method for preparing an insulating layer on the surface of a superconducting cable in improving the compressive strength of the superconducting cable after sintering.

[0015] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages: The superconducting cable manufactured by the present invention has two layers of reverse spirally wrapped insulation layers, which can effectively improve the performance of the cable, thereby avoiding the problem of gaps or breaks in the external insulation protection structure when the cable is bent. Specifically, the heat-resistant temperature of the superconducting cable provided by the present invention can reach 650°C and the withstand voltage strength can reach 2300V. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the preparation process of the superconducting cable provided by the present invention. DETAILED DESCRIPTION

[0018] The technical scheme of the present invention is described below in conjunction with the embodiments, but the present invention is not limited to the following embodiments. The experimental methods and detection methods described in each embodiment are conventional methods unless otherwise specified; the reagents and materials can be purchased on the market unless otherwise specified. The % in the following embodiments, unless otherwise specified, are all mass percentages. The ratios in the following embodiments, unless otherwise specified, are all mass ratios.

[0019] The glass fiber was purchased from Chongqing Tianze New Materials Co., Ltd. The specifications are D450 Y5, E225 Y3 and G150 Y1. The specific parameters are as follows:

[0020] Polyester fiber was purchased from Zhejiang Hailide New Materials Co., Ltd. with the specification of T712-226dtex-72f. The specific parameters are as follows: white, Denier 200, Dtex 226, fiber mesh 72, and dry heat shrinkage (117°C-2min-0.05cn / dtex) of 2.5%.

[0021] Example 1 This embodiment provides a method for preparing a superconducting cable.

[0022] The specific steps are as follows: S1, take a superconducting wire core; S2, using N insulating fibers arranged in parallel to be spirally wound on the surface of the superconducting wire core along the center line of the axis thereof in a first direction to obtain the first spirally wound layer (forward spirally wound layer); S3, using n parallel arranged insulating fibers to spirally wind the first spiral winding layer along the center line of the axis in a second direction to obtain the second spiral winding layer (reverse spiral winding layer), the first spiral winding layer and the second spiral winding layer being in opposite directions; S4. Insulating fibers are used on the surface of the second spiral winding layer, and the surface is covered by weaving with warp and weft threads in an offset manner, so as to form an insulating braided layer (braided layer).

[0023] Exemplarily, the N or the n is independently selected from positive integers.

[0024] Exemplarily, the spiral winding speed of the first spiral winding layer or the second spiral winding layer is independently selected from 150 to 300 turns / minute, and the spiral winding thickness is independently selected from 0.03 to 0.06 mm.

[0025] Exemplarily, the thickness of the braided layer is 0.03-0.08 mm.

[0026] Exemplarily, the braiding pitch of the braided layer is 8-12 mm.

[0027] Generally, the angle of the first direction or the second direction is independently selected from 30 to 60 degrees.

[0028] Example 2 This embodiment provides a process for preparing a superconducting cable.

[0029] This embodiment uses glass fiber D450 Y5.

[0030] The specific steps are as follows: S1. Take a superconducting wire core, and the diameter of the superconducting wire core is 0.8 mm; S2, winding four parallel-arranged glass fibers in a forward spiral direction on the surface of the superconducting wire core at a spiral winding speed of 200 turns / minute, thereby forming a first insulating layer (forward spiral winding layer); S3, winding four parallel arranged glass fibers in a reverse spiral around the surface of the first insulating layer at a spiral winding speed of 200 turns / minute, thereby forming a second insulating layer (reverse spiral winding layer); S4. The surface of the second insulating layer is covered with glass fiber braiding with a braiding pitch of 10 mm, thereby forming an insulating braided layer (braided layer).

[0031] The angles in the first direction or the second direction are both 45°, and the diameter of the insulated cable prepared in this embodiment is 0.95 mm.

[0032] Comparative Example 1 This comparative example provides a process for preparing a superconducting cable having a braided layer.

[0033] This comparative example uses glass fiber D450 Y5.

[0034] The specific steps are as follows: S1. Take a superconducting wire core, and the diameter of the superconducting wire core is 0.8 mm; S2. The surface of the superconducting wire core is covered with a braided coating using glass fibers for staggered weaving of warp and weft threads, with a weaving pitch of 10 mm, thereby forming an insulating braided layer (braided layer).

[0035] The number of braids of the insulating braided layer (braided layer) in this comparative example is one layer.

[0036] The diameter of the insulated cable prepared in this comparative example is 0.85 mm.

[0037] Comparative Example 2 This comparative example provides a process for preparing a superconducting cable with three braided layers.

[0038] This comparative example uses glass fiber D450 Y5.

[0039] S1. Take a superconducting wire core, and the diameter of the superconducting wire core is 0.8 mm; S2. The surface of the superconducting wire core is covered with a braided coating using glass fibers for staggered weaving of warp and weft threads, with a weaving pitch of 10 mm, thereby forming an insulating braided layer (braided layer).

[0040] S3. Repeat S2 to make multiple layers of insulating braided layers.

[0041] In this comparative example, the insulating braided layer (braided layer) has three braided layers, and the three braided layers realize staggered braiding of warp and weft.

[0042] The diameter of the insulated cable prepared in this comparative example is 0.95 mm.

[0043] The insulated cables prepared in Example 2 and Comparative Examples 1-2 were sintered and bent at 120° to test the compressive strength (refer to GB / T 4074.5-2008 Winding Wire Test Method Part 5: Electrical Properties). The test results are shown in the following table: Table 1: Same sintering temperature

[0044] Table 2: Same sintering time

[0045] The cables with a final withstand voltage greater than 500V are regarded as qualified products. Based on Tables 1 and 2 above, it can be seen that the withstand voltage of the insulated cable produced in Example 2 is significantly higher than the withstand voltage of the insulated cables produced in Comparative Examples 1 and 2. It can be seen from Comparative Examples 1 and 2 that simply increasing the number and thickness of the insulating layers can also improve the withstand voltage of the insulated cable, but the improvement is not high.

[0046] Example 3 This embodiment provides a process for preparing a superconducting cable.

[0047] This embodiment uses glass fiber E225 Y3.

[0048] The specific steps are as follows: S1. Take a superconducting wire core, and the diameter of the superconducting wire core is 1.0 mm; S2, winding a parallel arranged glass fiber in a forward spiral direction on the surface of the superconducting wire core at a spiral winding speed of 200 turns / minute, thereby forming a first insulating layer (forward spiral winding layer); S3, winding five glass fibers arranged in parallel in a reverse spiral on the surface of the first insulating layer at a spiral winding speed of 200 turns / minute, thereby forming a second insulating layer (reverse spiral winding layer); S4. The surface of the second insulating layer is covered with glass fiber braiding with a braiding pitch of 10 mm, thereby forming an insulating braided layer (braided layer).

[0049] The angles in the first direction or the second direction are both 45°, and the diameter of the insulated cable prepared in this embodiment is 1.15 mm.

[0050] Example 4 This embodiment provides a process for preparing a superconducting cable.

[0051] This embodiment uses polyester fiber T712-226dtex-72f.

[0052] The specific steps are as follows: S1. Take a superconducting wire core, and the diameter of the superconducting wire core is 1.0 mm; S2, winding three parallel-arranged polyester fibers in a forward spiral direction on the surface of the superconducting wire core at a spiral winding speed of 200 turns / minute, thereby forming a first insulating layer (forward spiral winding layer); S3, winding two parallel polyester fibers in a reverse spiral around the surface of the first insulating layer at a spiral winding speed of 200 turns / minute, thereby forming a second insulating layer (reverse spiral winding layer); S4. The second insulating layer is covered with polyester fibers by weaving, with a weaving pitch of 10 mm, so as to form an insulating braided layer (braided layer).

[0053] The angles in the first direction or the second direction are both 30°, and the diameter of the insulated cable prepared in this embodiment is 1.2 mm.

[0054] Example 5 This embodiment provides a process for preparing a superconducting cable.

[0055] This embodiment uses glass fiber G150 Y1.

[0056] The specific steps are as follows: S1. Take a superconducting wire core, and the diameter of the superconducting wire core is 0.8 mm; S2, winding four parallel-arranged glass fibers in a forward spiral direction on the surface of the superconducting wire core at a spiral winding speed of 200 turns / minute, thereby forming a first insulating layer (forward spiral winding layer); S3, winding four parallel arranged glass fibers in a reverse spiral around the surface of the first insulating layer at a spiral winding speed of 200 turns / minute, thereby forming a second insulating layer (reverse spiral winding layer); S4. The surface of the second insulating layer is covered with glass fiber braiding with a braiding pitch of 10 mm, thereby forming an insulating braided layer (braided layer).

[0057] The angles in the first direction or the second direction are both 60°, and the diameter of the insulated cable prepared in this embodiment is 1.0 mm.

[0058] For the insulated cables manufactured in the above-mentioned Examples 2 to 5, they were sintered, bent at 120° and then tested for compressive strength (refer to GB / T 4074.5-2008 Winding Wire Test Method Part 5: Electrical Properties). The test results are shown in the following table: Table 3: Compressive strength

[0059] As can be seen from Table 3, in the superconducting cable produced by the present invention, two layers of reverse spirally wrapped insulation layers are added, which can effectively improve the performance of the cable, thereby avoiding gaps or breaks in the external insulation protection structure when the cable is bent. The heat-resistant temperature can reach at least 650°C, and the compressive strength can reach 2300V.

[0060] As described above, the basic principle, main features and advantages of the present invention are well described. The above embodiments and descriptions are only descriptions of the preferred implementation modes of the present invention, and the present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, various changes and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the protection scope determined by the present invention.

Claims

1. A superconducting cable, comprising a superconducting wire core and an insulating layer arranged on the surface of the superconducting wire core, characterized in that: The insulating layer comprises, from the inside to the outside, a first spirally wound layer, a second spirally wound layer and a braided layer; The first helically wound layer is in an opposite direction to the second helically wound layer.

2. The superconducting cable according to claim 1, characterized in that: The first helically wound layer, the second helically wound layer or the braided layer are made of insulating fibers.

3. The superconducting cable according to claim 2, characterized in that: The insulating fibers are glass fibers and / or polyester fibers.

4. The superconducting cable according to claim 1, characterized in that: The thickness of the insulating layer is 0.1-0.2 mm.

5. A method for preparing an insulating layer on the surface of a superconducting cable, characterized in that: include: Prepare the superconducting cable according to any one of claims 1 to 4.

6. The method for preparing an insulating layer on the surface of a superconducting cable according to claim 5, characterized in that: include: The first spiral winding layer is prepared by spirally winding N insulating fibers arranged in parallel on the surface of the superconducting wire core along the center line of the axis thereof in a first direction; Using n parallelly arranged insulating fibers to spirally wind the first spirally wound layer along the center line of the axis toward a second direction to obtain the second spirally wound layer; installing the braided layer on the surface of the second spirally wound layer; The braided layer is woven by warp and weft in a staggered manner; The N or the n is independently selected from positive integers.

7. The method for preparing an insulating layer on the surface of a superconducting cable according to claim 6, characterized in that: The thickness of the braided layer is 0.03-0.08 mm.

8. The method for preparing an insulating layer on the surface of a superconducting cable according to claim 6, characterized in that: The spiral winding speed of the first spiral winding layer or the second spiral winding layer is independently selected from 150 to 300 turns / minute, and the spiral winding thickness is independently selected from 0.03 to 0.06 mm.

9. The method for preparing an insulating layer on the surface of a superconducting cable according to claim 6, characterized in that: The braiding pitch of the braided layer is 8-12 mm.

10. Use of the method for preparing an insulating layer on the surface of a superconducting cable according to any one of claims 5 to 9 in improving the compressive strength of the superconducting cable after sintering.

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