CN117790071A - Superconducting cable relay connector connecting system - Google Patents

Abstract

The invention provides a superconducting cable relay joint connection system, which comprises a relay cooling station, a first superconducting cable, a second superconducting cable and a relay joint; the relay connector comprises a connector shell, a plurality of shielding layer superconducting tapes fixed in the connector shell, copper connecting cylinders distributed on the inner peripheral sides of the shielding layer superconducting tapes, insulating partition plates fixed in the copper connecting cylinders and connecting electrodes fixed in the insulating partition plates, wherein the insulating partition plates divide the inner cavity of the connector shell into a first liquid nitrogen cavity and a second liquid nitrogen cavity which are not communicated with each other, a first interface and a liquid nitrogen outlet which are communicated with the first liquid nitrogen cavity, and a second interface and a liquid nitrogen inlet which are communicated with the second liquid nitrogen cavity are formed in the connector shell, and the liquid nitrogen outlet and the liquid nitrogen inlet are connected with a relay cooling station. The method can meet the electrical characteristics of the superconducting cable, can block the loss of liquid nitrogen, and can enhance the cold quantity and flow of the liquid nitrogen by combining the relay cooling station, so that the cold quantity and flow of the liquid nitrogen circulation in the long-length superconducting cable can be enhanced reliably.

Description

Superconducting cable relay connector connecting system

Technical Field

The invention relates to the technical field of superconducting cables, in particular to a superconducting cable relay joint connection system.

Background

The superconducting cable is a cable made of superconductors, has the advantages of large capacity, low loss, energy conservation, environmental protection and the like, and has been widely applied in the power industry. The superconducting cable is operated in a superconducting state using flowing liquid nitrogen as a cooling medium.

Along with the development of superconducting cable technology, a large-length superconducting cable is well applied, the length of the large-length superconducting cable is usually more than 5 km, and a cooling system relay station is required to be configured to enhance the cooling capacity and flow of liquid nitrogen circulation. However, the superconducting cable body is a continuous closed whole, and the splicing of the long-length superconducting cable is realized through the superconducting cable intermediate joint or the superconducting cable terminal, which cannot be well connected with the cooling system relay station, so that the operation of the long-length superconducting cable is not very stable.

Disclosure of Invention

In view of the above-described drawbacks of the prior art, an object of the present invention is to provide a superconducting cable relay joint connection system that reliably enhances the cooling capacity and flow rate of liquid nitrogen circulation in a long length superconducting cable.

In order to achieve the above object, the present invention provides a superconducting cable relay joint connection system including a relay cooling station, a first superconducting cable, a second superconducting cable, and a relay joint connected between the first superconducting cable and the second superconducting cable;

the first superconducting cable and the second superconducting cable both comprise at least one cable core, a heat-insulating pipe surrounding the periphery of the cable core and liquid nitrogen flowing between the periphery of the cable core and the inner periphery of the heat-insulating pipe, and the cable core comprises a core body and a cable shielding layer wrapping the periphery of the core body;

the relay connector comprises a connector shell, copper connecting cylinders, a plurality of shielding layer superconducting tapes, insulating partition boards and connecting electrodes, wherein the copper connecting cylinders are the same as the cable cores in number and are fixed in the connector shell, the shielding layer superconducting tapes are fixedly distributed on the peripheries of the copper connecting cylinders, the insulating partition boards are fixed in the copper connecting cylinders, the connecting electrodes are fixed in the insulating partition boards, the insulating partition boards divide an inner cavity of the connector shell into a first liquid nitrogen cavity and a second liquid nitrogen cavity which are not communicated with each other, and a first interface and a liquid nitrogen outlet which are all communicated with the first liquid nitrogen cavity, and a second interface and a liquid nitrogen inlet which are all communicated with the second liquid nitrogen cavity are formed in the connector shell;

the cable core of the first superconducting cable extends into the first liquid nitrogen cavity through the first interface, the core body of the first superconducting cable is connected with one end of the connecting electrode in the first liquid nitrogen cavity, and the cable shielding layer of the first superconducting cable is connected with one end of the copper connecting cylinder in the first liquid nitrogen cavity;

the cable core of the second superconducting cable stretches into the second liquid nitrogen cavity through the second interface, the core body of the second superconducting cable is connected with the other end of the connecting electrode in the second liquid nitrogen cavity, and the cable shielding layer of the second superconducting cable is connected with the other end of the copper connecting cylinder in the second liquid nitrogen cavity;

and the liquid nitrogen outlet and the liquid nitrogen inlet are respectively connected with the inlet and the outlet of the relay cooling station.

Further, one end of the copper connecting cylinder is a first conical connecting part arranged in the first liquid nitrogen cavity, the other end of the copper connecting cylinder is a second conical connecting part arranged in the second liquid nitrogen cavity, the diameters of the first conical connecting part and the second conical connecting part are gradually reduced along the direction away from the insulating spacer plate, the first conical connecting part is connected with the cable shielding layer of the first superconducting cable, and the second conical connecting part is connected with the cable shielding layer of the second superconducting cable.

Further, the joint housing has an inner-outer double-layer structure, and comprises an inner housing, an outer housing distributed outside the inner housing, and a first vacuum pumping chamber formed between the inner housing and the outer housing.

Further, the inner shell is provided with a connecting port at the copper connecting cylinder; the relay joint further comprises fixed support plates which are arranged at the two ends of the connecting port and are fixed on the inner wall of the joint shell, and fixed cylinders which are sleeved outside the copper connecting cylinders and the superconductive layers of the shielding layers, wherein the two ends of each copper connecting cylinder are respectively and fixedly arranged in the two fixed support plates in a penetrating way, and the two ends of each fixed cylinder are respectively fixed on the end faces of the two fixed support plates;

when the cable cores are multiple, a second vacuum pumping cavity is formed between the fixed supporting plate and the two adjacent fixed cylinders.

Further, the inner shell, the outer shell and the fixed cylinder are all stainless steel shells, and the fixed support plate is a stainless steel plate.

Further, a gap is formed between the fixed cylinder and the plurality of shielding layer superconducting tapes.

Further, the plurality of shielding layer superconducting tapes and the copper connecting cylinder are fixed through soldering.

As described above, the superconducting cable relay joint connection system according to the present invention has the following advantageous effects:

according to the method, the two sections of superconducting cables are spliced through the relay connector, and particularly the electric characteristics of the superconducting cables can be met through the structural arrangement of the relay connector, loss of liquid nitrogen can be blocked, the cooling capacity and the flow of the liquid nitrogen are enhanced by combining the relay cooling station, the circulating cooling capacity and the flow of the liquid nitrogen in the large-length superconducting cable are finally and reliably enhanced, and the stable operation of the large-length superconducting cable is reliably ensured.

Drawings

Fig. 1 is a schematic structural view of a first embodiment of a superconducting cable trunk joint connection system in the present application.

Fig. 2 is a schematic structural diagram of a second embodiment of a superconducting cable trunk joint connection system in the present application.

Fig. 3 is a cross-sectional view of the first superconducting cable or the second superconducting cable of fig. 2.

Description of element reference numerals

10. Relay cooling station

20. First superconducting cable

30. Second superconducting cable

40. Relay joint

41. Joint housing

411. First liquid nitrogen cavity

412. Second liquid nitrogen cavity

413. First interface

414. Liquid nitrogen outlet

415. Second interface

416. Liquid nitrogen inlet

42. Superconductive tape of shielding layer

43. Copper connecting cylinder

431. First conical connecting part

432. Second conical connecting part

44. Insulating partition board

45. Connection electrode

46. Inner shell

461. Connection port

47. Outer casing

48. Fixed support plate

49. Fixing cylinder

50. First vacuumizing cavity

60. Second vacuumizing cavity

Detailed Description

Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present invention, which is described by the following specific examples.

It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the invention to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the invention, are included in the spirit and scope of the invention which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like are used herein for descriptive purposes only and not for purposes of limitation, and are intended to limit the scope of the invention as defined by the claims and the relative terms thereof as construed as corresponding to the claims.

It will also be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected to the other element through intervening elements.

Furthermore, the descriptions of "first," "second," and the like, herein are for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present application.

The invention provides a superconducting cable relay joint connection system. As shown in fig. 1 or 2, the superconducting cable relay joint connection system includes a relay cooling station 10, a first superconducting cable 20, a second superconducting cable 30, and a relay joint 40, the first superconducting cable 20 and the second superconducting cable 30 are two-section spliced superconducting cables, and are connected by the relay joint 40, and the relay joint 40 is connected between the first superconducting cable 20 and the second superconducting cable 30.

As shown in fig. 1 or fig. 2 and 3, the first superconducting cable 20 and the second superconducting cable 30 have the same self-structure, and each of them includes at least one cable core, a heat-insulating pipe surrounding the outer periphery of the cable core, and liquid nitrogen flowing between the outer periphery of the cable core and the inner periphery of the heat-insulating pipe, the liquid nitrogen being a cooling medium, and the cable core further includes a core body and a cable shielding layer surrounding the outer periphery of the core body. The relay joint 40 is made to have two embodiments based on the cable cores according to the differences in the first superconducting cable 20 and the second superconducting cable 30, that is, the superconducting cable relay joint connection system is made to have two embodiments accordingly.

Embodiment one of superconducting Cable Relay Joint connection System

In the first embodiment of the superconducting-cable relay joint connection system, the cable cores in both the first superconducting cable 20 and the second superconducting cable 30 are one. Based on this, as shown in fig. 1, the relay connector 40 includes a connector housing 41 and a cable connection assembly fixed in the connector housing 41, the cable connection assembly divides the inner cavity of the connector housing 41 into two first liquid nitrogen cavities 411 and second liquid nitrogen cavities 412 which are not communicated with each other, a first interface 413 and a liquid nitrogen outlet 414 which are all communicated with the first liquid nitrogen cavities 411 are formed on the connector housing 41, and a second interface 415 and a liquid nitrogen inlet 416 which are all communicated with the second liquid nitrogen cavities 412 are formed on the connector housing 41. The cable connection assembly includes a copper connection cylinder 43 fixed in a connector housing 41, a plurality of shield layer superconducting tapes 42 fixedly distributed on the outer periphery of the copper connection cylinder 43, insulating spacer plates 44 fixed in the copper connection cylinder 43, and connection electrodes 45 fixed in the respective insulating spacer plates 44. The first liquid nitrogen cavity 411 and the second liquid nitrogen cavity 412 are distributed on two sides of the insulating partition plate 44, two ends of the copper connecting cylinder 43 are respectively arranged in the first liquid nitrogen cavity 411 and the second liquid nitrogen cavity 412, and two ends of the connecting electrode 45 are also respectively arranged in the first liquid nitrogen cavity 411 and the second liquid nitrogen cavity 412. In this embodiment, the first liquid nitrogen chamber 411 and the second liquid nitrogen chamber 412 are separated by the insulating partition plate 44 in the cable connection assembly, and then the first liquid nitrogen chamber 411 and the second liquid nitrogen chamber 412 are distributed on both sides of the insulating partition plate 44. The enclosure structure of the plurality of shield layer superconducting tapes 42 and the copper connection cylinder 43 are both cylindrical structures extending in the longitudinal direction of the first superconducting cable 20 and the second superconducting cable 30. The insulating spacer 44 has a circular plate structure.

Further, the connection structure among the relay cooling station 10, the first superconducting cable 20, the second superconducting cable 30, and the relay joint 40 is as follows: the insulating tube of the first superconducting cable 20 is connected with the joint housing 41 at the first interface 413, the cable core of the first superconducting cable 20 extends into the first liquid nitrogen cavity 411 through the first interface 413, the core body of the first superconducting cable 20 is connected with one end of the connecting electrode 45 in the first liquid nitrogen cavity 411, and the cable shielding layer of the first superconducting cable 20 is connected with one end of the copper connecting cylinder 43 in the first liquid nitrogen cavity 411. The insulating tube of the second superconducting cable 30 is connected with the joint housing 41 at the second interface 415, the cable core of the second superconducting cable 30 extends into the second liquid nitrogen cavity 412 through the second interface 415, the core of the second superconducting cable 30 is connected with the other end of the connecting electrode 45 in the second liquid nitrogen cavity 412, and the cable shielding layer of the second superconducting cable 30 is connected with the other end of the copper connecting cylinder 43 in the second liquid nitrogen cavity 412. A liquid nitrogen outlet 414 is connected to the inlet of the relay cooling station 10 and a liquid nitrogen inlet 416 is connected to the outlet of the relay cooling station 10.

In the superconducting cable relay joint connection system according to the present invention, the cable cores of the first superconducting cable 20 and the second superconducting cable 30 are connected by the connection electrode 45 and the copper connection tube 43 in the relay joint 40, and the electrical connection is achieved by the conduction of the copper connection tube 43 and the plurality of shielding layer superconducting tapes 42 on the outer periphery. The flowing liquid nitrogen in the first superconducting cable 20 flows into the first liquid nitrogen cavity 411 at the tail end of the first superconducting cable, flows into the relay cooling station 10 through the liquid nitrogen outlet 414, a flow increasing component and a cooling component are arranged in the relay cooling station 10, flow increasing and cooling treatments are carried out on the flowing liquid nitrogen, the treated liquid nitrogen flows into the second liquid nitrogen cavity 412 through the liquid nitrogen inlet 416, and then flows into the second superconducting cable 30 at the head end of the second superconducting cable 30, so that the circulating flow of the liquid nitrogen in the multi-section superconducting cable is realized. It is apparent that the closed flow structure of the liquid nitrogen at the junction 40 effectively blocks the liquid nitrogen from flowing out of the superconducting cable, avoids the loss of the liquid nitrogen, and particularly can increase the cooling capacity and flow rate of the liquid nitrogen flowing into the next section of superconducting cable and continuously cool the cable core of the subsequent superconducting cable.

Therefore, the two sections of superconducting cables are spliced through the relay connector 40, the electric characteristics of the superconducting cables can be met through the structural arrangement of the relay connector 40, loss of liquid nitrogen can be blocked, the cooling capacity and flow of the liquid nitrogen are enhanced by combining the relay cooling station 10, the circulating cooling capacity and flow of the liquid nitrogen in the long-length superconducting cables are finally and reliably enhanced, and stable operation of the long-length superconducting cables is reliably ensured.

Preferably, the insulating spacer 44 is made of a low temperature insulating material. As shown in fig. 1, the connection electrode 45 is preferably fixed at the center of the insulating partition plate 44, and the connection between the connection electrode 45 and the insulating partition plate 44 is sealed.

Further, as shown in fig. 1, one end of the copper connecting cylinder 43 is a first conical connecting portion 431 disposed in the first liquid nitrogen chamber 411, the other end of the copper connecting cylinder 43 is a second conical connecting portion 432 disposed in the second liquid nitrogen chamber 412, the diameters of the first conical connecting portion 431 and the second conical connecting portion 432 are gradually reduced along the direction away from the insulating spacer 44, the first conical connecting portion 431 is connected with the cable shielding layer of the first superconducting cable 20, the second conical connecting portion 432 is connected with the cable shielding layer of the second superconducting cable 30, and connection of the copper connecting cylinder 43 and the cable shielding layer is facilitated.

Further, as shown in fig. 1, the joint housing 41 has an inner-outer double-layer structure, and the joint housing 41 includes an inner housing 46, an outer housing 47 distributed outside the inner housing 46, and a first vacuum-pumping chamber 50 formed between the inner housing 46 and the outer housing 47, so as to better maintain a low-temperature operation environment and avoid loss of cold energy.

Further, as shown in fig. 1, the inner case 46 is provided with a connection port 461 at the copper connection cylinder 43; the cable connection assembly further includes fixing support plates 48 provided at both ends of the connection port 461 and welded to the inner wall of the joint housing 41, and fixing cylinders 49 provided around the outer circumferences of the copper connection cylinder 43 and the plurality of shield superconducting tapes 42. Wherein, both ends of the copper connecting cylinder 43 are respectively fixedly penetrated in the two fixed support plates 48, and each fixed support plate 48 is provided with a fixed hole, thereby fixing the copper connecting cylinder 43 in the inner shell 46. In the present embodiment, the copper connection cylinder 43 is fixedly fitted with the fixing hole of the fixing support plate 48 at the large diameter ends of the first and second conical connection parts 431 and 432. The two ends of the fixed cylinder 49 are bent with welding step parts extending radially outwards, and the two ends of the fixed cylinder 49 are respectively fixed on the end surfaces of the two fixed support plates 48 through the welding step parts, so that a first vacuumizing cavity 50 at the connecting port 461 is also formed on the outer peripheral side of the fixed cylinder 49.

Preferably, the plurality of shielding layer superconducting tapes 42 and the copper connection cylinder 43 are fixed by soldering, specifically, the plurality of shielding layer superconducting tapes 42 are distributed on the periphery of the copper connection cylinder 43 by low-temperature soldering, so that no gap exists between the plurality of shielding layer superconducting tapes 42 and the copper connection cylinder 43. However, a gap is provided between the plurality of shield superconducting tapes 42 and the fixing cylinder 49.

Preferably, the inner case 46, the outer case 47 and the fixing cylinder 49 are all stainless steel cases, the fixing support plate 48 is a stainless steel plate, and the outer circumference of the inner case 46 may be wrapped with a plurality of layers of heat insulating material. The inner housing 46, the stationary support plate 48 and the stationary cylinder 49 constitute an inner stainless steel seal structure of the joint housing 41.

Superconducting cable relay joint connection system embodiment two

In the second embodiment of the superconducting cable relay joint connection system, as shown in fig. 3, three cable cores in the first superconducting cable 20 and the second superconducting cable 30 are all three, that is, three-phase superconducting cables. Based on this, the relay joint 40 of the second embodiment of the superconducting-cable relay-joint connection system is different from the relay joint 40 of the first embodiment of the superconducting-cable relay-joint connection system in that: as shown in fig. 2, in the relay joint 40 of the second embodiment of the superconducting cable relay joint connection system, there are three units composed of a copper connection cylinder 43, a shielding layer superconducting tape 42, an insulating spacer 44, a connection electrode 45, and a fixing cylinder 49. Specifically, the cable connection assembly includes three copper connection cylinders 43 distributed at 120 ° intervals, a plurality of shield layer superconducting tapes 42 fixedly distributed at the outer periphery of each copper connection cylinder 43, insulating spacer plates 44 fixed in each copper connection cylinder 43, connection electrodes 45 fixed in each insulating spacer plate 44, two fixing support plates 48 both welded and fixed in an inner case 46, and a fixing cylinder 49 sleeved at the outer periphery of each copper connection cylinder 43 and the plurality of shield layer superconducting tapes 42. In this embodiment, the first liquid nitrogen chamber 411 and the second liquid nitrogen chamber 412 are partitioned by the insulating partition plate 44 and the fixed support plate 48, and then the first liquid nitrogen chamber 411 and the second liquid nitrogen chamber 412 are distributed on both sides of the insulating partition plate 44.

The insulating tube of the first superconducting cable 20 is connected with the joint housing 41 at the first interface 413, three cable cores of the first superconducting cable 20 extend into the first liquid nitrogen cavity 411 through the first interface 413, cores of the three cable cores are respectively connected with one ends of the three connecting electrodes 45 in the first liquid nitrogen cavity 411, and cable shielding layers of the three cable cores are respectively connected with one ends of the three copper connecting cylinders 43 in the first liquid nitrogen cavity 411. The insulating tube of the second superconducting cable 30 is connected with the joint housing 41 at the second interface 415, three cable cores of the second superconducting cable 30 extend into the second liquid nitrogen cavity 412 through the second interface 415, cores of the three cable cores are respectively connected with the other ends of the three connecting electrodes 45 in the second liquid nitrogen cavity 412, and cable shielding layers of the three cable cores are respectively connected with the other ends of the three copper connecting cylinders 43 in the second liquid nitrogen cavity 412. Thus, the first superconducting cable 20 and the second superconducting cable 30 of the three-phase structure are connected. In addition, a second vacuumizing cavity 60 is formed between the fixed support plate 48 and the two adjacent fixed cylinders 49, so that the loss of cold energy is avoided.

Preferably, there are three fixing holes on each fixing support plate 48, and the three fixing holes are in one-to-one correspondence with the three copper connecting cylinders 43.

In summary, the present application has the following advantages:

1. the splicing of the two sections of superconducting cables is realized, and the cooling capacity and the flow of liquid nitrogen circulation in the long-length superconducting cable are reliably enhanced, so that the stable operation of the long-length superconducting cable is reliably ensured;

2. the cable shielding layers of two superconducting cables are connected by welding the shielding layer superconducting tapes 42 on the periphery of the copper connecting cylinder 43 in a distributed manner, and the connection resistance is effectively reduced by overlapping the distribution of the shielding layer superconducting tapes 42 on the outer layer; meanwhile, the inner copper connecting cylinder 43 effectively transfers heat, and almost coincides with the liquid nitrogen temperature in the joint housing 41, namely almost coincides with the liquid nitrogen temperature in the superconducting cable, so that the superconductivity of the outer shielding layer superconducting tape 42 at the periphery side is ensured;

3. the insulating partition plate 44 is simple in structure, and reliability is further improved;

4. the annular fixed support plate 48 is adopted as a transition, so that welding heat cannot damage the peripheral side shielding layer superconducting tape 42, and a sealing structure is realized.

In summary, the present invention effectively overcomes the disadvantages of the prior art and has high industrial utility value.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (7)

1. A superconducting cable trunk joint connection system, characterized by: comprises a relay cooling station (10), a first superconducting cable (20), a second superconducting cable (30), and a relay joint (40) connected between the first superconducting cable (20) and the second superconducting cable (30);

the first superconducting cable (20) and the second superconducting cable (30) both comprise at least one cable core, a heat-insulating pipe surrounding the outer periphery of the cable core, and liquid nitrogen flowing between the outer periphery of the cable core and the inner periphery of the heat-insulating pipe, wherein the cable core comprises a core body and a cable shielding layer wrapping the outer periphery of the core body;

the relay connector (40) comprises a connector shell (41), copper connecting cylinders (43) which are the same as the number of cable cores and are fixed in the connector shell (41), a plurality of shielding layer superconducting tapes (42) fixedly distributed on the periphery of each copper connecting cylinder (43), insulating partition boards (44) fixed in each copper connecting cylinder (43) and connecting electrodes (45) fixed in each insulating partition board (44), the inner cavity of the connector shell (41) is divided into a first liquid nitrogen cavity (411) and a second liquid nitrogen cavity (412) which are not communicated with each other by the insulating partition boards (44), a first interface (413) and a liquid nitrogen outlet (414) which are all communicated with the first liquid nitrogen cavity (411), and a second interface (415) and a liquid nitrogen inlet (416) which are all communicated with the second liquid nitrogen cavity (412) are formed on the connector shell (41);

the cable core of the first superconducting cable (20) stretches into the first liquid nitrogen cavity (411) through the first interface (413), the core body of the first superconducting cable (20) is connected with one end of the connecting electrode (45) in the first liquid nitrogen cavity (411), and the cable shielding layer of the first superconducting cable (20) is connected with one end of the copper connecting cylinder (43) in the first liquid nitrogen cavity (411); the cable core of the second superconducting cable (30) stretches into the second liquid nitrogen cavity (412) through the second interface (415), the core body of the second superconducting cable (30) is connected with the other end of the connecting electrode (45) in the second liquid nitrogen cavity (412), and the cable shielding layer of the second superconducting cable (30) is connected with the other end of the copper connecting cylinder (43) in the second liquid nitrogen cavity (412);

the liquid nitrogen outlet (414) and the liquid nitrogen inlet (416) are respectively connected with the inlet and the outlet of the relay cooling station (10).

2. The superconducting cable trunk joint connection system of claim 1, wherein: copper connecting cylinder (43) one end is first circular cone connecting portion (431) of arranging in first liquid nitrogen chamber (411), copper connecting cylinder (43) other end is second circular cone connecting portion (432) of arranging in second liquid nitrogen chamber (412), the diameter of first circular cone connecting portion (431) and second circular cone connecting portion (432) all reduces gradually along the direction of keeping away from insulating division board (44), first circular cone connecting portion (431) links to each other with the cable shielding layer of first superconducting cable (20), second circular cone connecting portion (432) links to each other with the cable shielding layer of second superconducting cable (30).

3. The superconducting cable trunk joint connection system of claim 1, wherein: the connector housing (41) is of an inner-outer double-layer structure, and the connector housing (41) comprises an inner housing (46), an outer housing (47) distributed outside the inner housing (46), and a first vacuum pumping cavity (50) formed between the inner housing (46) and the outer housing (47).

4. The superconducting cable trunk joint connection system of claim 3, wherein: the inner shell (46) is provided with a connecting port (461) at the copper connecting cylinder (43); the relay joint (40) further comprises fixed support plates (48) which are arranged at two ends of the connecting port (461) and are fixed on the inner wall of the joint shell (41), and fixed cylinders (49) which are sleeved on the peripheries of the copper connecting cylinders (43) and the shielding layer superconducting tapes (42), wherein two ends of the copper connecting cylinders (43) are respectively and fixedly arranged in the two fixed support plates (48) in a penetrating way, and two ends of the fixed cylinders (49) are respectively fixed on the end faces of the two fixed support plates (48);

when the cable cores are multiple, a second vacuum pumping cavity (60) is formed between the fixed supporting plate (48) and the two adjacent fixed cylinders (49).

5. The superconducting cable trunk joint connection system of claim 4, wherein: the inner shell (46), the outer shell (47) and the fixed cylinder (49) are all stainless steel shells, and the fixed support plate (48) is a stainless steel plate.

6. The superconducting cable trunk joint connection system of claim 4, wherein: a gap is formed between the fixed cylinder (49) and the plurality of shielding layer superconducting tapes (42).

7. The superconducting cable trunk joint connection system of claim 1, wherein: the shielding layer superconductive tapes (42) and the copper connecting cylinders (43) are fixed by soldering.