A device for testing the bending characteristics of a high-temperature superconducting cable and a testing method thereof

Abstract

The application discloses a device for testing bending characteristics of high-temperature superconducting cables and a testing method thereof, and belongs to the technical field of high-temperature superconducting technology. The device comprises a bending plate, a plurality of coaxial and different-radius circular-arc grooves are formed in the bending plate, and the circular-arc grooves are used for bending cables; and a conductive clamping module is arranged on the bending plate and located at both ends of the groove opening of the circular-arc groove. The conductive clamping module comprises a connected conductive column and a sample clamp, the conductive column is connected with a power cable, and the sample clamp is used for fixing the bent cable. The device for testing the bending characteristics of the high-temperature superconducting cables is used in cooperation with the bending plate and the conductive clamping module, effectively solves the inconvenience of repeatedly disassembling and assembling the external cable during the experiment and the external cable when the high-temperature superconducting cable is tested under different bending radii, simplifies the testing steps, effectively improves the testing efficiency, and reduces the sample damage risk caused by disassembling and assembling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature superconducting materials, and particularly relates to a device for testing bending characteristics of a high-temperature superconducting cable and a testing method thereof. BACKGROUND

[0002] At present, high-temperature superconducting cables carrying tens of kiloamperes of current are expected to replace low-temperature NbTi and Nb3Sn cables and be applied to the magnet systems of large scientific devices such as high-field (>20T) tokamaks and large accelerators. Massachusetts Institute of Technology in the United States first proposed a stacked twisted (TSTC) high-temperature superconducting cable with simple preparation process and strong current-carrying capacity. Subsequently, the American Advanced Superconductivity Technology Company (ACT) proposed a coiled (CORC) high-temperature superconducting cable, and the German KIT proposed a Roebel high-temperature superconducting cable. In addition, based on the TSTC cable in the United States, the Italian ENEA, the Swiss SPC, the German KIT, the Japanese NIFS, the North China Electric Power University in China, the Shanghai Jiaotong University, and the Institute of Plasma Physics, Chinese Academy of Sciences, and other institutions have made further development and research on it.

[0003] High-temperature superconducting cables with different structures will not only be subjected to tensile, torsional, bending, and transverse stress during the twisting of multi-stage cables and the winding of magnets, but also be subjected to huge low-temperature shrinkage stress and electromagnetic stress under high field and large current during the operation of the magnet. These will affect the critical current and mechanical stability of the high-temperature superconducting cable, and even threaten the safety of the entire device. Therefore, the accuracy of the mechanical experimental parameters of the high-temperature superconducting cable is one of the key factors affecting the twisting of the cable, the design and manufacture of the magnet, and the safe operation thereof. The bending characteristic test is the most common test in high-temperature superconducting cables, which will provide experimental data support for the design, manufacture, and safe operation of the multi-stage cable and the magnet.

[0004] However, the current device for testing the bending characteristics of the high-temperature superconducting cable is relatively rough, and usually draws an arc line on an epoxy plate and then nails a few nails as bending support points, which leads to uneven and inadequate bending of the cable test, and easily causes the cable test to be subjected to concentrated force at the support points, resulting in damage to the cable test and affecting the test results and test efficiency. In addition, after the sample clamp and the cable are connected, they need to be fixed again separately, which makes the installation, fixation, and replacement of the test radius of the clamps at both ends of the sample extremely inconvenient, and often causes damage to the cable test due to improper operation, further reducing the effectiveness and efficiency of the test. SUMMARY

[0005] The present application aims to provide a device for testing the bending characteristics of high-temperature superconducting cables and a testing method thereof, so as to solve the problem of unevenness, incompleteness, low effectiveness and low efficiency of the existing device for testing the bending characteristics of high-temperature superconducting cables. The device is used to test the change rule of the critical current of the cable under different bending radius conditions, thereby providing important guidance for the design and manufacture of high-temperature superconducting magnets, cables or conductors.

[0006] The technical solution of the present application to solve the above technical problems is as follows:

[0007] The present application provides a device for testing the bending characteristics of high-temperature superconducting cables, comprising:

[0008] A bending plate is provided, and a plurality of coaxial and different radius circular arc grooves are formed in the bending plate, and the circular arc grooves are used to bend the cable.

[0009] A conductive clamping module is provided on the bending plate and located at both ends of the groove opening of the circular arc groove.

[0010] The conductive clamping module comprises a conductive column and a sample clamp, one end of the conductive column is connected to a power cable, the other end of the conductive column is connected to the sample clamp, and the sample clamp is used to fix the bent cable.

[0011] Further, in the device for testing the bending characteristics of high-temperature superconducting cables, the conductive clamping module further comprises a fixing column connected below the sample clamp, and the fixing column is arranged in the circular arc groove on the bending plate.

[0012] Further, in the device for testing the bending characteristics of high-temperature superconducting cables, the sample clamp comprises a matched upper cover plate and a lower cover plate, and the upper cover plate and the lower cover plate are provided with semicircular arc grooves for fixing the cable.

[0013] Further, in the device for testing the bending characteristics of high-temperature superconducting cables, the conductive column and the sample clamp are connected and fixed by a U-shaped clamping groove.

[0014] Further, in the device for testing the bending characteristics of high-temperature superconducting cables, the conductive column and the fixing column are arranged on one side of the sample clamp.

[0015] Further, in the device for testing the bending characteristics of high-temperature superconducting cables, a trapezoidal boss is provided on the bending plate, and a plurality of coaxial and different radius circular arc grooves are formed on the trapezoidal boss.

[0016] Further, in the device for testing the bending property of a high-temperature superconducting cable, the bending plate is provided with a circular arc through slot corresponding to the extension direction of the two ends of the circular arc slot on the trapezoidal boss.

[0017] Further, in the device for testing the bending property of a high-temperature superconducting cable, the bottom of the bending plate is provided with an insulating foot.

[0018] Further, in the device for testing the bending property of a high-temperature superconducting cable, the two sides of the bending plate are provided with a circular through hole for mounting a lifting ring.

[0019] The application also provides a testing method based on the above-mentioned device for testing the bending property of a high-temperature superconducting cable, comprising:

[0020] Prepare the high-temperature superconducting cable sample to be tested, and install the voltage lead.

[0021] Install the conductive clamping module at both ends of the cable sample, then place the cable sample in the test Dewar, and fill liquid nitrogen to immerse the entire cable sample;

[0022] Connect the external power line to the conductive column, and connect the voltage signal line to the collector thereof, turn on the power supply to start the test;

[0023] Before the bending test starts, measure the initial critical current of the current;

[0024] Install the cable sample on the bending plate through the fixing column of the conductive clamping module, and place the entire device in the Dewar to complete the critical current measurement under the bending radius;

[0025] Pull out the cable sample together with the conductive clamping module, install it in the next bending circular arc slot, and complete the critical current measurement;

[0026] Repeat the previous step, and sequentially apply the bending test radii from large to small until the critical current of the sample decays to less than 95% of the initial value and stops.

[0027] The application has the following beneficial effects:

[0028] The device for testing the bending property of a high-temperature superconducting cable provided by the application is used to test the bending property of a high-temperature superconducting cable at low temperature, and provides reliable parameter support for the design and manufacture of high-temperature superconducting multi-stage cables and magnets. The device bends the cable sample through the bending plate, and fixes the bent cable sample through the conductive clamping module, which are used in cooperation to effectively solve the inconvenience of repeated disassembly and installation of external cables during the test of the high-temperature superconducting cable under different bending radii, simplify the test steps, effectively improve the test efficiency, and reduce the risk of sample damage caused by disassembly and installation.

[0029] The device for testing the bending property of the high-temperature superconducting cable provided by the application is characterized in that the bending plate is provided with a circular-arc through slot, and the conductive clamping module is provided with a fixing column matched with the circular-arc through slot, which together constitute the main body of the plug-in test method, so that the sample can be quickly installed and fixed in the circular-arc slot with different bending radii, and the test steps are further simplified and the test efficiency is improved.

[0030] The device for testing the bending property of the high-temperature superconducting cable provided by the application is characterized in that the bending plate is provided with a circular-arc through slot, and the conductive clamping module is provided with a fixing column matched with the circular-arc through slot, which together constitute the main body of the plug-in test method, so that the sample can be quickly installed and fixed in the circular-arc slot with different bending radii, and the test steps are further simplified and the test efficiency is improved.

[0031] The device for testing the bending property of the high-temperature superconducting cable provided by the application is characterized in that the bending plate is provided with a circular-arc through slot, and the conductive clamping module is provided with a fixing column matched with the circular-arc through slot, which together constitute the main body of the plug-in test method, so that the sample can be quickly installed and fixed in the circular-arc slot with different bending radii, and the test steps are further simplified and the test efficiency is improved.

[0032] The device for testing the bending property of the high-temperature superconducting cable provided by the application is characterized in that the bending plate is provided with a circular-arc through slot, and the conductive clamping module is provided with a fixing column matched with the circular-arc through slot, which together constitute the main body of the plug-in test method, so that the sample can be quickly installed and fixed in the circular-arc slot with different bending radii, and the test steps are further simplified and the test efficiency is improved.

[0033] The device for testing the bending property of the high-temperature superconducting cable provided by the application is characterized in that the bending plate is provided with a circular-arc through slot, and the conductive clamping module is provided with a fixing column matched with the circular-arc through slot, which together constitute the main body of the plug-in test method, so that the sample can be quickly installed and fixed in the circular-arc slot with different bending radii, and the test steps are further simplified and the test efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the embodiments of the application, constitute a part of the application, and do not constitute a limitation on the embodiments of the application. In the drawings:

[0035] Figure 1 It is a structural schematic view of the device for testing the bending property of the high-temperature superconducting cable of the application;

[0036] Figure 2 It is a top view schematic view of the device for testing the bending property of the high-temperature superconducting cable of the application;

[0037] Figure 3 It is a structural schematic view of the conductive clamping module in the device for testing the bending property of the high-temperature superconducting cable of the application;

[0038] Figure 4 It is experimental data of the test example of the application Figure 1 ;

[0039] Figure 5 It is experimental data of the test example of the applicationFigure 2 .

[0040] Markings in the drawings and corresponding component names:

[0041] In the figure: 10-bending plate, 11-circular arc groove, 12-trapezoidal boss, 13-circular arc through groove, 14-insulating foot, 15-circular through hole, 20-conductive clamping module, 21-conductive column, 22-fixing column, 23-upper cover plate, 24-lower cover plate, 25-U-shaped clamping groove. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0044] Embodiment 1

[0045] Please refer to Figure 1 , Figure 2 and Figure 3 , the embodiments of the present application provide a device for testing the bending characteristics of high-temperature superconducting cables, which is suitable for liquid nitrogen environment, preferably for liquid nitrogen 77K environment, comprising:

[0046] Bending plate 10, a plurality of coaxial and different radius circular arc grooves 11 are arranged on the bending plate 10, and the circular arc grooves 11 are used for bending the cable. The radii of the circular arc grooves 11 are arranged in order from large to small, and the radii of the circular arc grooves 11 can be customized in different sizes according to different specifications of the test, which is used to bend the cable to a specified bending radius.

[0047] Conductive clamping module 20, the conductive clamping module 20 is arranged on the bending plate 10 and located at both ends of the circular arc groove 11; the conductive clamping module 20 comprises: a conductive column 21 and a sample clamp, one end of the conductive column 21 is connected with a power cable, the other end of the conductive column 21 is connected with the sample clamp, and the sample clamp is used to fix the bent cable.

[0048] Compared with the prior art, the high-temperature superconducting cable will be inevitably bent when being bent, and is prone to over-bending or under-bending during the bending process, thereby causing damage to the cable sample or inaccuracy of the test result.

[0049] If the cable test is bent according to the current document, an arc line is usually drawn on an epoxy board, and then several nails are nailed as bending support points, so that the cable sample is unevenly and incompletely bent, and the cable is easily subjected to concentrated force at the support points, thereby causing damage to the cable test and affecting the test result and test efficiency. In addition, such a test method causes great inconvenience in the installation and fixation of the clamps at both ends of the cable test, and often causes damage to the cable test due to improper operation, thereby further reducing the effectiveness and efficiency of the test.

[0050] Therefore, the embodiment of the present application provides a device for testing the bending characteristics of a high-temperature superconducting cable, which is used to test the bending characteristics of the high-temperature superconducting cable at low temperature, and provides reliable parameter support for the design and manufacture of high-temperature superconducting multi-stage cables and magnets. The device is matched with a bending plate 10 and a conductive clamping module 20, the conductive clamping module 20 is used to fix the left and right ends of the high-temperature superconducting cable sample, and is symmetrically distributed, and forms a plug-in fixed structure with the circular arc through slot 13 on the bending plate 10 through the fixed column 22, so that the cable sample can be quickly fixed in the curved circular arc slot 11, thereby realizing the bending characteristic test of the cable test.

[0051] In some schemes of the embodiment, the conductive clamping module 20 further comprises a fixed column 22 connected below the sample clamp, and the fixed column 22 is arranged in the circular arc slot 11 of the bending plate 10.

[0052] In some schemes of the embodiment, the sample clamp comprises a matched upper cover plate 23 and lower cover plate 24, the upper cover plate 23 is provided with through holes arranged in a matrix and a semicircular slot for fixing the cable, and the lower cover plate 24 is provided with threaded holes arranged in a matrix and a semicircular slot for fixing the cable. The shape and size of the upper cover plate 23 and the lower cover plate 24 are matched, and the upper cover plate 23 and the lower cover plate 24 are matched to clamp the cable sample together. Specifically, the lower end of the lower cover plate 24 is provided with a threaded hole for connecting with the fixed column 22.

[0053] In some schemes of the embodiment, the conductive column 21 and the sample clamp are connected and fixed through the U-shaped clamping groove 25. Specifically, the upper end of the conductive column 21 is provided with a through hole for connecting with the power cable, and the lower end is provided with a through hole connected with the U-shaped clamping groove 25. The lower cover plate 24 is provided with a through hole connected with the U-shaped clamping groove 25 on the outer side, the U-shaped clamping groove 25 is connected to the lower end of the conductive column 21, and is connected to the outer side of the lower cover plate 24.

[0054] In order to facilitate sample fixation and ensure that there is sufficient current transfer length after the test sample is electrified, and to ensure that the current has completely flowed into the superconducting layer in the effective test length, thereby ensuring the effectiveness of the test, the conductive column 21 and the fixing column 22 in the conductive clamping module 20 are arranged at the end part close to the cable test.

[0055] In some schemes of the embodiment, the conductive column 21 and the fixing column 22 are arranged on one side of the sample clamp. The conductive column 21 and the fixing column 22 are not arranged in the middle of the sample clamp, but close to one end. In this way, the sample can be fixed more conveniently, and at the same time, it is ensured that the clamped sample has sufficient current flow length, thereby reducing the current transfer length in the non-clamped part of the sample and ensuring the effectiveness of the test.

[0056] In some schemes of the embodiment, the curved plate 10 is provided with a trapezoidal boss 12, and a plurality of coaxial and different-radius circular arc grooves 11 are arranged on the trapezoidal boss 12. By arranging the circular arc grooves 11 on the trapezoidal boss 12, the purpose is to ensure that the circular arc length under different radii is less than the effective length of the sample, thereby ensuring the installation of the sample and the effectiveness of the test.

[0057] In some schemes of the embodiment, the curved plate 10 is provided with a trapezoidal boss 12, and a plurality of coaxial and different-radius circular arc grooves 11 are arranged on the trapezoidal boss 12. By arranging the circular arc grooves 11 on the trapezoidal boss 12, the purpose is to ensure that the circular arc length under different radii is less than the effective length of the sample, thereby ensuring the installation of the sample and the effectiveness of the test.

[0058] In some schemes of the embodiment, the curved plate 10 is provided with a trapezoidal boss 12, and a plurality of coaxial and different-radius circular arc grooves 11 are arranged on the trapezoidal boss 12. By arranging the circular arc grooves 11 on the trapezoidal boss 12, the purpose is to ensure that the circular arc length under different radii is less than the effective length of the sample, thereby ensuring the installation of the sample and the effectiveness of the test.

[0059] In some schemes of the embodiment, the curved plate 10 is provided with a trapezoidal boss 12, and a plurality of coaxial and different-radius circular arc grooves 11 are arranged on the trapezoidal boss 12. By arranging the circular arc grooves 11 on the trapezoidal boss 12, the purpose is to ensure that the circular arc length under different radii is less than the effective length of the sample, thereby ensuring the installation of the sample and the effectiveness of the test.

[0060] In the embodiment, each part of the conductive clamping module 20 is connected as a whole by screws or bolts, and all the materials thereof are made of red copper with good conductivity.

[0061] Embodiment 2

[0062] The embodiment of the application provides a test method for testing the bending characteristic of a high-temperature superconducting cable, adopts the device for testing the bending characteristic of the high-temperature superconducting cable in the embodiment 1, and comprises the following steps.

[0063] Step one: preparing a high-temperature superconducting cable sample to be tested; first, the installation of voltage leads is completed through spot welding at a proper position of the sample.

[0064] Step two: installing two conductive clamping modules 20 at two ends of the sample through screws, then placing the sample into a test Dewar, and filling liquid nitrogen to immerse the whole sample.

[0065] Step three: connecting the external power line with the conductive column 21, connecting the voltage signal line with a collector thereof, and turning on the power supply to start the test.

[0066] Step four: completing the measurement of the initial critical current of the current before the bending test starts.

[0067] Step five: installing the sample on the bending plate 10 through the fixing column 22 of the conductive module, and placing the whole device into the Dewar to complete the measurement of the critical current under the bending radius.

[0068] Step six: pulling out the sample together with the conductive clamping module 20, installing into the next bending circular groove 11, and completing the measurement of the critical current.

[0069] Step seven: repeating step six, and the bending radii tested in the process are sequentially applied in the order from large to small. Until the critical current of the sample is degraded to below 95% of the initial value, the process is stopped.

[0070] Test example

[0071] The test method in the embodiment 2 is adopted, the high-temperature superconducting cable sample is prepared by selecting the high-temperature superconducting tapes provided by Suzhou New Material. The sample is a high-temperature superconducting cable with a diameter of 4 mm, which is composed of 20 high-temperature superconducting tapes with a width of 2 mm, filler solder and an oxygen-free copper tube. The sample has a length of 50 cm and an effective length of 30 cm. The voltage lead spacing is set to 5 cm for one test section, and there are totally three test sections. The test sample number is 9, different bending angles 0°, 45° and 90° are tested, three samples are tested for each angle, the test temperature is liquid nitrogen 77 K, and the obtained normalized critical power curves with different bending radii are respectively shown in Figure 4 and Figure 5 (Note: the bending radius is defined as 0° when it is perpendicular to the tape width, and 90° when it is parallel to the tape width)

[0072] It can be seen from the above examples that the bending characteristic test of the high-temperature superconducting cable is carried out by using the patent and the test method, the minimum bending radius of the cable bending is 8 cm, at this time the critical current of all samples is still more than 70% of the initial value. At the same time, the experimental results show that the current-carrying capacity of each single cable sample on different test sections changes simultaneously and with the same amplitude with the change of the bending radius, and the results of the three samples at the same angle are consistent in repeatability, which shows that the sample is not damaged in the bending process; in addition, the sample is changed quickly and smoothly under different bending radii in the test process, and the high-temperature superconducting cable is not damaged, and a good normalized critical current curve with the change of the bending radius is obtained, the results show that the device and the test method of the application obtain good and reliable test results, have good practicability, and can be popularized.

[0073] The above specific embodiments further illustrate the purposes, technical solutions and beneficial effects of the application, and it should be understood that the above are only specific embodiments of the application and are not used to limit the protection scope of the application, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A device for testing the bending characteristics of high-temperature superconducting cables, characterized in that, include: A bending plate (10) is provided with a trapezoidal boss (12), and a plurality of coaxial circular arc grooves (11) with different radii are provided on the trapezoidal boss (12). The circular arc grooves (11) are used to bend the cable. Conductive clamping module (20), the conductive clamping module (20) is disposed on the bending plate (10) and located at both ends of the groove of the arc groove (11); The conductive clamping module (20) includes: a conductive post (21), a sample clamp and a fixing post (22). One end of the conductive post (21) is connected to a power cable, and the other end of the conductive post (21) is connected to the sample clamp. The sample clamp is used to fix the bent cable. The fixing post (22) is connected below the sample clamp and is located in the arc groove (11) on the bending plate (10).

2. The apparatus for testing the bending characteristics of high-temperature superconducting cables according to claim 1, characterized in that, The sample fixture includes a matching upper cover plate (23) and a lower cover plate (24), both the upper cover plate (23) and the lower cover plate (24) being provided with semi-circular grooves for fixing cables.

3. The apparatus for testing the bending characteristics of high-temperature superconducting cables according to claim 1, characterized in that, The conductive post (21) is connected and fixed to the sample clamp via a U-shaped groove (25).

4. The apparatus for testing the bending characteristics of high-temperature superconducting cables according to claim 1, characterized in that, The conductive post (21) and the fixing post (22) are disposed on one side of the sample holder.

5. The apparatus for testing the bending characteristics of high-temperature superconducting cables according to claim 1, characterized in that, The curved plate (10) has an arc through groove (13) extending from both ends of the arc groove (11) on the trapezoidal boss (12).

6. The apparatus for testing the bending characteristics of high-temperature superconducting cables according to claim 1, characterized in that, The bottom of the curved plate (10) is provided with insulating pads (14).

7. The apparatus for testing the bending characteristics of high-temperature superconducting cables according to claim 1, characterized in that, The curved plate (10) has circular through holes (15) on both sides for installing lifting rings.

8. A test method based on the apparatus for testing the bending characteristics of high-temperature superconducting cables according to any one of claims 1-7, characterized in that, include: Prepare the high-temperature superconducting cable sample to be tested and complete the installation of the voltage leads; The conductive clamping module (20) is installed at both ends of the cable sample, and then the cable sample is placed in the test Dewar and filled with liquid nitrogen until the entire cable sample is submerged. Connect the external power cord to the conductive post (21) and connect the voltage signal line to its acquisition unit. Turn on the power to start the test. Before the bending test begins, the initial critical current is measured. The cable sample is mounted on the bending plate (10) through the fixing post (22) of the conductive clamping module (20), and the entire device is placed inside the Dewar to complete the critical current measurement under the bending radius. The cable sample, along with the conductive clamping module (20), is pulled out and installed into the next curved arc groove (11), and the critical current measurement is completed. Repeat the previous step, applying bending test radii from large to small, until the critical current of the sample decays to less than 95% of the initial value.

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