Turnable superconducting current device with variable power-on length and adjusting method thereof

Abstract

The invention relates to a breakable superconducting current device with variable power-on length and an adjusting method thereof, the device comprises a superconducting container, a current lead, a sealing ring, a conductive spring, a connector, a high-voltage connecting rod and a superconducting connecting line, the current lead passes through the superconducting container, and the current lead and the superconducting container are sealed through the sealing ring; the high-voltage connecting rod is connected or disconnected with the connector through the conductive spring; the current lead, the conductive spring and the connector are tightly connected in sequence to form an electrical path, compression of the conductive spring is achieved by pressing the current lead, and then the power-on length is adjusted. And the high-voltage connecting rod is connected with the superconducting connecting wire to form an electrical path. Compared with the prior art, the superconducting magnet only electrifies the current lead when needed, heat leakage caused by the current lead is reduced, the heat loss of the current lead is reduced, the use of a cooling medium is reduced, and the energy utilization efficiency of a system is improved.

Description

Technical Field

[0001] The invention relates to the field of electric power technology, and in particular to a superconducting current device with variable and disconnectable current-carrying length and a regulating method thereof. Background Art

[0002] A current lead is a conductive line that connects a power source and a load and is widely used in the electric power field. In the superconducting field, many superconducting power equipment applications such as superconducting power transmission, superconducting substations, and superconducting magnets require the use of current leads to connect external power sources and internal loads. However, since superconductors only have superconducting properties at low temperatures, in the superconducting field, the temperature difference between the two sections of the current lead is extremely large, usually exceeding 200°C, and can even reach 300°C. Conventional superconducting current leads use metals with good conductivity such as copper and aluminum as conductors, and conductors with good conductivity usually have good thermal conductivity, so the heat leakage of the current lead is also extremely large. The currently commonly used method is to calculate the optimal aspect ratio of the current lead to minimize heat leakage.

[0003] However, the optimal aspect ratio is only applicable when the current is constant. In the actual application of superconducting magnets, the current lead is usually not energized for a long time. Normally, the current lead is only used for magnetization in superconducting magnets. If the current lead is connected for a long time, the current lead will become a very large source of heat leakage. When the power is first turned on, the superconducting magnet needs to be magnetized, so a large current is required; if magnetization is required during maintenance, a smaller current is required; after magnetization, the current lead needs to be disconnected to reduce the heat leakage caused by the current lead. For example, Chinese patent CN101446598B discloses a variable-section current lead suitable for a high-temperature superconducting tape critical current characteristic test system, including: a straight copper rod variable-section current lead, which uses an improved air-cooled current lead segmentation calculation method to optimize the geometric parameters of the variable-section current lead; a mixed lead segment in which copper strands are welded in parallel with BSCCO strips, which is used to connect the end of the straight copper rod variable-section lead with the YBCO strip, and the current lead cannot be disconnected. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a superconducting current device with variable and disconnectable power-on length and its adjustment method, so that the superconducting magnet can energize the current lead only when needed, thereby reducing the heat leakage caused by the current lead itself, reducing the heat loss of the current lead, reducing the use of cooling medium, and improving the energy utilization efficiency of the system.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A superconducting current device with a variable and disconnectable energized length comprises: a superconducting container, a current lead, a sealing ring, a conductive spring, a connector, a high-voltage connecting rod and a superconducting connecting wire, wherein the current lead passes through the superconducting container and is sealed between the current lead and the superconducting container by the sealing ring; the high-voltage connecting rod is connected or disconnected with the connector by the conductive spring; the current lead, the conductive spring and the connector are tightly connected in sequence to form an electrical path, and the conductive spring is compressed by pressing the current lead to adjust the energized length; the high-voltage connecting rod is connected to the superconducting connecting wire to form an electrical path.

[0007] Furthermore, the current lead can slide in the sealing ring, and the sealing effect does not fail during the sliding process.

[0008] Furthermore, the states of the conductive spring include a free state, a compressed state and an extreme compressed state;

[0009] When the conductive spring is in the free state, the high-voltage connecting rod is disconnected from the connecting head, and the current lead is not energized;

[0010] When the conductive spring is in the compressed state, the high-voltage connecting rod is tightly connected to the connecting head, and a small current passes through the current lead;

[0011] When the conductive spring is in the ultimate compression state, the conductive spring's current-carrying cross-section increases, the high-voltage connecting rod is tightly connected to the connecting head, and a large current passes through the current lead.

[0012] Furthermore, the superconducting connecting wire is immersed in a low-temperature medium.

[0013] Furthermore, the liquid level of the cryogenic medium is higher than the upper end of the superconducting connecting wire and lower than the upper end of the high-voltage connecting rod.

[0014] Furthermore, the material of the superconducting connecting wire is a conductive element that requires a cooling medium, and the low-temperature medium includes multiple types of liquid nitrogen and liquid helium.

[0015] Furthermore, the shape and size of the connecting head match the high-voltage connecting rod.

[0016] Furthermore, the material of the current lead, the conductive spring, the connector and the high-voltage connecting rod is the material used to make conductive elements.

[0017] Furthermore, the material used to make the conductive element includes multiple materials selected from copper and aluminum.

[0018] According to another aspect of the present invention, there is provided a method for regulating a superconducting current device with a variable and disconnectable current-carrying length, comprising the following steps:

[0019] Designing an optimal length-to-diameter ratio of the current lead according to the maximum current, producing the current lead according to the optimal length-to-diameter ratio, determining that the conductive spring is in a free state according to the depth of the superconducting container where the current lead is located and the fixed position of the high-voltage connecting rod, and measuring the length of the current lead;

[0020] Marking scales on the current lead according to the length of the current lead to determine the position of the current lead when the conductive spring is in a free state, a compressed state, and an extreme compressed state;

[0021] When the conductive spring is in a free state, the current when power is applied is estimated. When the current changes, the state of the conductive spring is adjusted according to the current. If the current is small, the current lead is pressed downward so that the conductive spring is in a compressed state. If the current is very large, the current lead is continued to be pressed downward so that the conductive spring is in an extreme compression state.

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

[0023] 1. The present invention connects or disconnects the high-voltage connecting rod with the connector according to actual application conditions by arranging a conductive spring. When power is on, the high-voltage connecting rod is connected to the connector to form an electrical path. When power is not on, the conductive spring is in a free state, the high-voltage connecting rod is disconnected from the connector, and the current lead is not energized. By pressing the current lead to switch the energized and disconnected states, the superconducting magnet energizes the current lead only when needed, thereby reducing the heat leakage caused by the current lead itself, reducing the heat loss of the current lead, reducing the use of cooling medium, and improving the energy utilization efficiency of the system.

[0024] 2. The present invention provides a conductive spring, and compresses the conductive spring according to the current size to switch the compression state of the conductive spring. When the conductive spring is in the compressed state, the high-voltage connecting rod is connected to the connecting head, and the current lead can pass a small current; when the conductive spring is in the extreme compression state, the conductive cross-section of the conductive spring increases, and the current lead can pass a large current, thereby adapting to different currents, realizing the adjustment of the length of the current lead, and adapting to the particularity of the superconducting magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a superconducting current device with a variable and disconnectable current-carrying length proposed by the present invention;

[0026] Figure 2 Schematic diagrams of the states of a conductive spring, wherein (2a) is a schematic diagram of the compressed state of the conductive spring, and (2b) is a schematic diagram of the ultimate compressed state of the conductive spring;

[0027] Figure 3Schematic diagrams of the structures of the connectors in the embodiments, wherein (3a) is a schematic diagram of the bismuth telluride connector and the connector being connected side by side, and (3b) is a schematic diagram of the bismuth telluride connector being directly connected to the conductive spring.

[0028] Legend: 1. Superconducting container; 2. Current lead; 3. Sealing ring; 4. Conductive spring; 5. Connector; 51. Bismuth telluride connector; 6. High-voltage connecting rod; 61. Bismuth telluride high-voltage connecting rod; 7. Superconducting connecting wire. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0030] Example 1

[0031] This embodiment provides a superconducting current device with variable and disconnectable current length, such as Figure 1 As shown, it includes: a superconducting container 1, a current lead 2, a sealing ring 3, a conductive spring 4, a connector 5, a high-voltage connecting rod 6 and a superconducting connecting wire 7. The current lead 2 passes through the superconducting container 1, and the sealing ring 3 is used to seal the current lead 2 and the superconducting container 1; the high-voltage connecting rod 6 is connected or disconnected with the connector 5 through the conductive spring 4; the current lead 2, the conductive spring 4 and the connector 5 are tightly connected in sequence to form an electrical path, and the conductive spring 4 is compressed by pressing the current lead 2, thereby adjusting the energized length; the high-voltage connecting rod 6 is connected to the superconducting connecting wire 7 to form an electrical path.

[0032] The current lead 2, the conductive spring 4, the connector 5, and the high-voltage connecting rod 6 are made of copper, aluminum, or other common materials with good conductivity that can be used to make conductive elements.

[0033] The current lead 2 can slide in the sealing ring 3, and the sealing effect does not fail during the sliding process. Other conductive elements can be connected above the current lead 2, and the sealing structure formed with the superconducting container 1 and the sealing ring 3 can also be implemented by the conductive element;

[0034] The conductive spring 4 must have spring properties, i.e., compressible and resettable, and when the conductive spring 4 is extremely compressed, the conductive spring 4 must be cylindrical; the states of the conductive spring 4 include a free state, a compressed state, and an extremely compressed state. When the conductive spring 4 is in a free state, the high-voltage connecting rod 6 is disconnected from the connector 5, and the current lead 2 is not energized. When the conductive spring 4 is in a compressed state, the high-voltage connecting rod 6 is tightly connected to the connector 5, and a small current passes through the current lead 2. When the conductive spring 4 is in an extremely compressed state, the energized cross-section of the conductive spring 4 increases, the high-voltage connecting rod 6 is tightly connected to the connector 5, and a large current passes through the current lead 2.

[0035] The superconducting connecting wire 7 is immersed in a cryogenic medium 8, and the liquid level of the cryogenic medium 8 is higher than the upper end of the superconducting connecting wire 7 and lower than the upper end of the high-voltage connecting rod 6. The cryogenic medium 8 is usually liquid nitrogen. When using a low-temperature superconducting connecting wire, the cryogenic medium 8 can be replaced with liquid helium. The superconducting connecting wire 7 can be replaced with any other conductive element that may appear in the future and requires a cooling medium, and the cryogenic medium 8 includes the types of cryogenic media required by the above conductive elements.

[0036] The shape and size of the connector 5 match those of the high-voltage connecting rod 6 . When the conductive spring 4 is compressed, the connector 5 and the high-voltage connecting rod 6 are in close contact.

[0037] The present embodiment provides a method for regulating a superconducting current device with a variable and disconnectable current length, comprising the following steps:

[0038] S1. Design an optimal aspect ratio of the current lead 2 according to the maximum current, produce the current lead 2 according to the optimal aspect ratio, determine that the conductive spring 4 is in a free state according to the depth of the superconducting container 1 where the current lead 2 is located and the fixed position of the high-voltage connecting rod, and measure the length of the current lead 2;

[0039] S2. Mark the scale on the current lead 2 according to the length of the current lead 2 to determine the position of the current lead 2 when the conductive spring 4 is in a free state, a compressed state and an extreme compressed state;

[0040] S3, when the conductive spring 4 is in a free state, the current when the power is on is estimated. When the current changes, the state of the conductive spring 4 is adjusted according to the current. If the current is small, the current lead 2 is pressed downward to make the conductive spring 4 in a compressed state, such as Figure 2 If the current is very large, the current lead 2 is pressed downward, so that the conductive spring 4 is in an extreme compression state, as shown in (2a); Figure 2 as shown in (2b).

[0041] Example 2

[0042] This embodiment provides a structure of a connector 5. In this embodiment, the connector 5 and the high-voltage connecting rod 6 are made of copper, and a bismuth telluride connector 51 is provided on the connector 5, and the bismuth telluride connector 51 is connected to the connector 5 by means of crimping or friction welding to ensure electrical performance. A bismuth telluride high-voltage connecting rod 61 is provided on the high-voltage connecting rod 6, and the bismuth telluride high-voltage connecting rod 61 is connected to the high-voltage connecting rod 6 by means of crimping or friction welding to ensure electrical performance.

[0043] like Figure 3As shown in (3a), the bismuth telluride connector 51 and the connector 5 can be connected side by side; the bismuth telluride high-voltage connecting rod 61 and the high-voltage connecting rod 6 can be connected side by side. As long as the connection strength between the two material connectors can be guaranteed, and the current can pass through the bismuth telluride connector 51 and the connector 5 in sequence. There is no restriction on the order in which the current passes through the bismuth telluride connector 51 and the connector 5. It can pass through the bismuth telluride connector 51 first, or it can pass through the connector 5 first, but it cannot pass through both at the same time. There is no restriction on the order in which the current passes through the bismuth telluride high-voltage connecting rod 61 and the high-voltage connecting rod 6. It can pass through the bismuth telluride high-voltage connecting rod 61 first, or it can pass through the high-voltage connecting rod 6 first, but it cannot pass through both at the same time.

[0044] The connector 5 and the high-voltage conductive rod 6 can be made of aluminum or other common materials with good conductivity that can be used to make conductive elements; the bismuth telluride connector 51 and the bismuth telluride high-voltage connecting rod 61 can be made of other new materials with good conductivity but poor thermal conductivity.

[0045] The rest is the same as in Example 1.

[0046] Example 3

[0047] This embodiment provides a connection method between a connector 5 and a conductive spring, such as Figure 3 As shown in (3b), the bismuth telluride connector 51 is directly connected to the conductive spring 4, so that the current passes through the conductive spring 4, the bismuth telluride connector 51 and the connector 5 in sequence. This structure needs to ensure that the conductive spring 4 and the bismuth telluride connector 51 will not be peeled off during use. The conductive spring 4 can be connected to the bismuth telluride connector 51 or the connector 5, but it must be ensured that the current passes through the bismuth telluride connector 51 and the connector 5 in sequence.

[0048] The rest is the same as in Example 1.

[0049] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A superconducting current device with variable and disconnectable current-carrying length, characterized in that: include: A superconducting container (1), a current lead (2), a sealing ring (3), a conductive spring (4), a connector (5), a high-voltage connecting rod (6) and a superconducting connecting wire (7); the current lead (2) passes through the superconducting container (1), and the sealing ring (3) seals the current lead (2) and the superconducting container (1); the high-voltage connecting rod (6) is connected or disconnected with the connector (5) through the conductive spring (4); the current lead (2), the conductive spring (4) and the connector (5) are tightly connected in sequence to form an electrical path; the conductive spring (4) is compressed by pressing the current lead (2), thereby adjusting the energized length; the high-voltage connecting rod (6) is connected to the superconducting connecting wire (7) to form an electrical path.

2. The superconducting current device with variable and disconnectable current-carrying length according to claim 1, characterized in that: The current lead (2) can slide inside the sealing ring (3), and the sealing effect does not fail during the sliding process.

3. The superconducting current device with variable and disconnectable current-carrying length according to claim 1, characterized in that: The states of the conductive spring (4) include a free state, a compressed state and an extreme compressed state; When the conductive spring (4) is in the free state, the high-voltage connecting rod (6) is disconnected from the connecting head (5), and the current lead (2) is not energized; When the conductive spring (4) is in the compressed state, the high-voltage connecting rod (6) is tightly connected to the connecting head (5), and a small current passes through the current lead (2); When the conductive spring (4) is in the extreme compression state, the conductive cross-section of the conductive spring (4) increases, the high-voltage connecting rod (6) is tightly connected to the connecting head (5), and a large current passes through the current lead (2).

4. The superconducting current device with variable and disconnectable current-carrying length according to claim 1, characterized in that: The superconducting connecting wire (7) is immersed in a low-temperature medium (8).

5. The superconducting current device with variable and disconnectable current-carrying length according to claim 4, characterized in that: The liquid level of the low-temperature medium (8) is higher than the upper end of the superconducting connecting wire (7) and lower than the upper end of the high-voltage connecting rod (6).

6. The superconducting current device with variable and disconnectable current-carrying length according to claim 4, characterized in that: The material of the superconducting connecting wire (7) is a conductive element that requires a cooling medium, and the low-temperature medium (8) includes multiple types of liquid nitrogen and liquid helium.

7. The superconducting current device with variable and disconnectable current-carrying length according to claim 1, characterized in that: The shape and size of the connecting head (5) match those of the high-voltage connecting rod (6).

8. The superconducting current device with variable and disconnectable current-carrying length according to claim 1, characterized in that: The materials of the current lead (2), the conductive spring (4), the connector (5) and the high-voltage connecting rod (6) are materials used for making conductive elements.

9. The superconducting current device with variable and disconnectable current-carrying length according to claim 8, characterized in that: The material used to make the conductive element includes copper and aluminum.

10. A method for regulating a superconducting current device with a variable and disconnectable current-carrying length according to any one of claims 1 to 9, characterized in that: The following steps are involved: Designing an optimal length-to-diameter ratio of the current lead (2) according to the maximum current, producing the current lead (2) according to the optimal length-to-diameter ratio, determining that the conductive spring (4) is in a free state according to the depth of the superconducting container (1) where the current lead (2) is located and the fixed position of the high-voltage connecting rod, and measuring the length of the current lead (2); Marking scales on the current lead (2) according to the length of the current lead (2) to determine the position of the current lead (2) when the conductive spring (4) is in a free state, a compressed state, and an extreme compressed state; When the conductive spring (4) is in a free state, the current when power is applied is estimated. When the current changes, the state of the conductive spring (4) is adjusted according to the current. If the current applied is small, the current lead (2) is pressed downward, so that the conductive spring (4) is in a compressed state. If the current applied is very large, the current lead (2) is further pressed downward, so that the conductive spring (4) is in an extreme compressed state.

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