CN111987685A

CN111987685A - Terminal structure of superconducting cable

Info

Publication number: CN111987685A
Application number: CN202010851124.6A
Authority: CN
Inventors: 宗曦华; 张喜泽; 张大义; 喻志广; 张智勇; 韩云武; 王京; 程雪雪
Original assignee: Shanghai International Superconducting Technology Co ltd
Current assignee: Shanghai International Superconducting Technology Co ltd
Priority date: 2020-08-21
Filing date: 2020-08-21
Publication date: 2020-11-24
Anticipated expiration: 2040-08-21
Also published as: CN111987685B

Abstract

The invention discloses a terminal structure of a superconducting cable, which comprises a current lead-out pipe arranged in a terminal sleeve, wherein one end of the current lead-out pipe is in conductive connection with the superconducting cable, the other end of the current lead-out pipe is exposed from the end part of the terminal sleeve to form an exposed end, a cavity is arranged in the current lead-out pipe, the exposed end of the current lead-out pipe is provided with a lead-out hole communicated with the cavity, a sealing cover is arranged on the lead-out hole, a signal lead is arranged in the cavity of the current lead-out pipe in a penetrating manner, and the tail end of the signal lead is led out from the sealing cover. The invention not only ensures the electric field balance of the superconducting cable terminal, but also realizes the leading-out of the signal lead from the low-temperature, high-voltage and high-pressure environment, and can realize the measurement of the temperature of the cable conductor and other non-electric quantity measurement of a high-voltage area under the condition of the net hanging operation of a superconducting cable system.

Description

Terminal structure of superconducting cable

Technical Field

The present invention relates to a superconducting cable, and more particularly, to a terminal structure of a superconducting cable.

Background

The superconducting cable is a power cable made of superconducting materials, is used for transmitting high-density electric energy, and has the advantages of low resistance, low loss, environmental protection and the like. Whether the superconducting material is in a superconducting state or not is the most critical index for safe operation of the superconducting cable, and when the superconducting material is in a deep superconducting state, the superconducting cable is the strongest in electric energy transmission capacity, and can be determined to be in a safe state basically. The most direct method for monitoring whether the superconducting material is in a superconducting state is to measure the temperature of the superconducting material of the conductor layer, however, the characteristics of the superconducting material, the low-temperature insulation and the like of the superconducting cable have hard requirements on the operating environments such as low temperature, high voltage, high pressure and the like, and it is difficult to arrange a temperature measuring sensor in the conductor layer or the high voltage area and lead out a signal lead to the external normal temperature environment.

With the application and development of the superconducting cable technology, the real-time monitoring of the state of the superconducting cable by arranging various probes or sensors in the superconducting cable also becomes an increasingly urgent need, but no good solution is provided for how the probes or sensors are arranged, particularly how the signal leads of the probes or sensors are led out in the low-temperature, high-voltage and high-pressure environments.

The chinese invention patent CN109855759B discloses a temperature measurement system for high temperature superconducting cable, which is to install optical fiber into the superconducting cable in advance when the superconducting cable is manufactured, and arrange a thermal resistor at the terminal (terminal cooling system) of the superconducting cable to form a composite temperature measurement component of optical fiber temperature measurement and thermal resistor temperature measurement, so as to measure the temperature along the high temperature superconducting cable and the temperature of the terminal cooling system. However, the patent does not mention how to lead the signal lead of the low-temperature optical fiber and the thermal resistor out of the low-temperature, high-voltage and high-pressure environment.

Chinese patent application CN103247995A discloses a terminal structure of a superconducting cable, which includes a hollow tubular conductor lead-out rod, the conductor lead-out rod can lead current into or out of the superconducting cable, and the hollow tubular conductor lead-out rod is cooled from the inside by liquid nitrogen, so that heat can be reliably prevented from flowing into the superconducting cable at ultralow temperature from the normal temperature region through the conductor lead-out rod. The purpose of the conductor lead-out rod is only limited to optimizing the heat transfer performance of the current lead tube, and the lead-out mode of the signal lead is not involved.

Disclosure of Invention

The invention provides a terminal structure of a superconducting cable, which can reliably lead out a signal lead.

In order to solve the technical problems, the invention adopts the following technical scheme: a terminal structure of a superconducting cable comprises a current leading-out pipe arranged in a terminal sleeve, wherein one end of the current leading-out pipe is in conductive connection with the superconducting cable, the other end of the current leading-out pipe is exposed from the end part of the terminal sleeve to form an exposed end, a cavity is arranged in the current leading-out pipe, the exposed end of the current leading-out pipe is provided with a leading-out hole communicated with the cavity, a sealing cover is arranged on the leading-out hole, a signal lead is arranged in the cavity of the current leading-out pipe in a penetrating mode, and the tail end of the signal lead is led out from the sealing cover.

Preferably, the superconducting cable includes a conductor layer and an insulation layer disposed outside the conductor layer, an end portion of the superconducting cable is located inside the terminal bushing, an end portion of the conductor layer is exposed from the insulation layer, and the current lead-out pipe is connected to the conductor layer through a connector.

Preferably, a voltage-sharing cover is sleeved outside the connector.

Preferably, the signal lead is connected to a thermal resistor or thermocouple disposed at an end of the conductor layer within the terminal sleeve.

Preferably, the signal lead is connected with an acquisition module positioned outside the sealing cover, and the acquisition module is in signal connection with a control module.

Preferably, the acquisition module is connected with a wireless module, and the control module is connected with a receiving module.

Preferably, the end of the terminal sleeve is provided with a grading ring, and the acquisition module and the wireless module are arranged on the inner side of the grading ring.

Preferably, the conductor layer includes a supporting conductor and a superconducting layer formed by a superconducting tape, the signal lead is connected with a temperature measuring optical fiber, and the temperature measuring optical fiber and the superconducting tape are wound on the outer side of the supporting conductor in parallel.

Preferably, the signal lead is connected with a distributed optical fiber measurer outside the sealing cover.

Preferably, the superconducting layers comprise a first superconducting layer, a second superconducting layer and a third superconducting layer which are coaxially arranged, the end parts of the first superconducting layer, the second superconducting layer and the third superconducting layer are sequentially arranged in a staggered manner from inside to outside and are respectively in conductive connection with the first current outlet pipe, the second current outlet pipe and the third current outlet pipe; a first temperature measuring optical fiber, a second temperature measuring optical fiber and a third temperature measuring optical fiber are respectively arranged in the first superconducting layer, the second superconducting layer and the third superconducting layer, and a first signal lead, a second signal lead and a third signal lead which are connected with the first temperature measuring optical fiber, the second temperature measuring optical fiber and the third temperature measuring optical fiber are respectively arranged in the cavities of the first current leading-out tube, the second current leading-out tube and the third current leading-out tube in a penetrating manner; and a first insulating layer, a second insulating layer and a third insulating layer are respectively arranged outside the first superconducting layer, the second superconducting layer and the third superconducting layer.

The terminal structure of the superconducting cable adopts the hollow current lead-out pipe, the cavity of the current lead-out pipe is penetrated with the signal lead wire for connecting the sensor for monitoring the state of the superconducting cable, and the cavity of the current lead-out pipe is filled with liquid nitrogen and forms vaporized nitrogen at the upper normal temperature section, thereby realizing the reliable transmission of power current and sensor signals from low-temperature, high-voltage and high-pressure environments to external normal-temperature and normal-pressure environments. The invention not only ensures the electric field balance of the superconducting cable terminal, but also realizes the leading-out of the signal lead, and can realize the measurement of the temperature of the cable conductor and other non-electric quantity measurement of a high-voltage area under the condition of the net hanging operation of the superconducting cable system.

The invention can realize temperature measurement of key components in the superconducting cable and the superconducting cable terminal under low temperature, high voltage and high pressure environment, or temperature measurement and vibration measurement distributed along the length of the superconducting cable, effectively maintains the balance and stability of the electric field in the superconducting cable terminal, reduces the risk of electrical breakdown caused by the cross-over from a high voltage area to a low voltage area, enables the temperature monitoring of the most core superconducting material of the superconducting cable to be possible, can acquire and monitor the core operation parameters of the superconducting cable system, and greatly ensures the safe operation of the superconducting cable system.

Drawings

Fig. 1 is a schematic view of a terminal structure of a superconducting cable of the present invention.

Fig. 2 is a schematic diagram of a lead-out mode of a signal lead wire in the invention.

Fig. 3 is a schematic cross-sectional view of a superconducting cable relating to the present invention.

Fig. 4 is a schematic diagram of another lead-out mode of the signal lead wire in the invention.

Fig. 5 is a schematic view of a sealing cap according to the present invention.

Fig. 6 is a schematic view of a terminal structure of a three-phase coaxial superconducting cable of the present invention.

Fig. 7 is a schematic cross-sectional view of a three-phase coaxial superconducting cable according to the present invention.

In the figure:

i Normal temperature section

II transition section

III low temperature stage

1. Current leading-out tube

2. Signal lead

3. Thermal resistance or thermocouple

4. Sealing cover

5. Terminal sleeve

7. Superconducting cable

8. Connector with a locking member

9. Voltage-equalizing cover

10. Hollow cavity

11. Connecting terminal

12. Exposed end

13. Lead-out hole

40. Sealing ring

41. Cover plate

42. Leading-out terminal

43. Insulating seal

51. Grading ring

61. Acquisition module

62. Power supply module

63. Wireless module

64. Current induction coil

65. Receiving module

66. Control module

67. Connecting optical fibers

68. Distributed optical fiber measurer

70. Conductive layer

71. Supporting conductor

72. Superconducting layer

73. Temperature measuring optical fiber

74. Insulating layer

75. Protective layer

76. Stress cone

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and are not intended to limit the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

As shown in fig. 1, the terminal structure of a superconducting cable of the present invention includes a terminal sleeve 5 disposed at the end of a superconducting cable 7, a current outlet tube 1 is disposed in the terminal sleeve 5, a cavity 10 is disposed inside the current outlet tube 1, a signal lead 2 is disposed in the cavity 10 of the current outlet tube, one end of the current outlet tube 1 is conductively connected to the superconducting cable 7, the other end of the current outlet tube 1 is exposed from the upper end of the terminal sleeve 5 to be a bare end, and a connection terminal 11 is disposed on the bare end for connecting a conventional cable or a power bus. The terminal sleeve 5 can be divided into a normal temperature section I, a transition section II and a low temperature section III in sequence from top to bottom, the low temperature section III of the terminal sleeve 5 is filled with a low temperature medium, such as liquid nitrogen, and the cavity 10 of the current lead-out pipe 1 is also partially filled with liquid nitrogen, so that the current lead-out pipe 1 can be prevented from conducting external heat to the superconducting cable 7.

As shown in fig. 2, the exposed end 12 of the current lead-out tube 1 is provided with a lead-out hole 13 communicated with the cavity 10, the lead-out hole 13 is provided with a sealing cover 4, and the tail end of the signal lead-out tube 2 is led out from the sealing cover 4.

Referring to fig. 1, a superconducting cable 7 includes a conductor layer 70 and an insulation layer 74 disposed outside the conductor layer, the conductor layer 70 generally includes a supporting conductor and a superconducting layer, an end portion of the superconducting cable 7 is positioned inside a terminal bushing 5, the insulation layer 74 is exposed from a rear end of a stress cone 76, an end portion of the conductor layer 70 is exposed from a rear end of the insulation layer 74, and a current lead-out pipe 1 is connected to the conductor layer 70 through a connector 8. The signal lead 2 is connected to a thermal resistor or thermocouple 3, which is arranged at the end of the conductor layer 70 in the terminal bushing, and which is used for measuring the temperature of the conductor layer 70 or of the area where the conductor layer 70 is connected to the connector 8. In order to equalize the electric field, a voltage equalizing cover 9 is provided around the connector 8, and a thermal resistor or thermocouple 3 is also provided inside the voltage equalizing cover 9.

Referring to fig. 2, an electrical signal generated by a thermal resistor or thermocouple (or other type of sensor) is transmitted from a low temperature, high voltage, high pressure, low temperature section to a normal temperature, normal pressure environment outside the superconducting cable terminal through a signal lead 2. Therefore, the end of the signal lead 2 led out from the sealing cover 4 can be connected with the collecting module 61 located outside the sealing cover 4, and the collecting module 61 is in signal connection with a control module 66. In a preferred embodiment, the acquisition module 61 is connected to a wireless module 63, the wireless module 63 is preferably a wifi module, and the control module 66 is connected to a receiving module 65. In this way, the sensor signal collected by the collection module 61 can be transmitted to the control module 66 of the remote zero-potential safety zone in a wireless communication manner. The control module 66 processes the collected signals and passes them up to the superconducting cable monitoring system to evaluate and identify the operating condition of the superconducting cable. A grading ring 51 is provided at the end of the terminal sleeve 5, and the collection module 61 and the wireless module 63 are provided inside the grading ring 51. In addition, a current induction coil 64 can be sleeved outside the current leading-out tube 1 to generate induction current and transmit the induction current to the power module 62, and the power module 62 provides working power for the acquisition module 61 and the wireless module 63.

Referring to fig. 5, the sealing cover 4 includes a cover plate 41 capable of being fixed on the outlet hole 13 of the current outlet pipe, and a sealing ring 40 is provided between the cover plate 41 and the current outlet pipe 1; one or more leading-out terminals 42 penetrate through the cover plate 41, are inwards used for being connected with the signal lead 2, and are outwards used for being connected with the acquisition module 61; the insulating seal 43 is used to seal and fix the terminals 42 to the cover plate 41, and the insulating seal 43 can be made by, for example, a glass sintering process.

In another embodiment of the invention, a temperature measuring optical fiber is arranged in the superconducting cable, so that the temperature distribution in the whole length range of the superconducting cable can be measured. As shown in fig. 3, the superconducting cable sequentially includes a conductor layer, an insulating layer 74 and a protective layer 75 from inside to outside, wherein the conductor layer further includes a supporting conductor 71 and a superconducting layer 72 made of a superconducting tape, a temperature measuring fiber 73 is disposed outside the supporting conductor 71, and the temperature measuring fiber 73 and the superconducting tape are wound in parallel on the outside of the supporting conductor 71.

As shown in fig. 4, the signal lead 2 connected to the temperature measuring fiber 73 is also an optical fiber, the temperature measuring fiber 73 and the signal lead 2 can be fused by a fusion splicer, the signal lead 2 passes through the sealing cover 4 and is connected to a distributed fiber measurer 68 in a far-end zero-potential safety zone by a connecting fiber 67, the distributed fiber measurer 68 processes and analyzes the collected optical fiber signal, and transmits the collected signal upward to a superconducting cable monitoring system to evaluate and identify the operating state of the superconducting cable. Thus, the optical signal in the temperature measuring fiber 73 is transmitted from the low-temperature section of low temperature, high voltage, and high pressure to the normal temperature and normal pressure environment outside the superconducting cable terminal through the signal lead 2. The raman temperature measurement principle employed by the temperature measuring fiber 73 and the distributed fiber optic measuring device 68 is a well-known technique.

Referring to fig. 5, when a temperature measuring optical fiber is used as the temperature measuring sensor, the signal lead and the leading-out terminal 42 in fig. 5 are both optical fibers, and the insulating seal 43 may be made of polyolefin.

The present invention is also applicable to a three-phase coaxial superconducting cable. As shown in fig. 7, the three-phase coaxial superconducting cable includes, in order from inside to outside, a support conductor 71, a first superconducting layer 72A, a first insulating layer 74A, a second superconducting layer 72B, a second insulating layer 74B, a third superconducting layer 72C, a third insulating layer 74C, and a protective layer 75, which are coaxially arranged, as viewed in cross section. In the first superconducting layer 72A, a first temperature measuring fiber 73A is wound outside the supporting conductor 71 in parallel with the superconducting tape; in the second superconducting layer 72B, a second temperature measuring fiber 73B is wound outside the first insulating layer 74A in parallel with the superconducting tape; in the third superconducting layer 72C, a third temperature measuring fiber 73C is wound outside the second insulating layer 74B in parallel with the superconducting tape.

As shown in fig. 6, at the terminal end of the superconducting cable 7, the first superconducting layer 72A, the second superconducting layer 72B and the third superconducting layer 72C are arranged in layers in sequence from inside to outside, that is, the first superconducting layer 72A, the second superconducting layer 72B and the third superconducting layer 72C are shortened in sequence, the first superconducting layer 72A is conductively connected to the first current lead-out pipe 1A through the first connector 8A, the second superconducting layer 72B is conductively connected to the second current lead-out pipe 1B through the second connector 8B, and the third superconducting layer 72C is conductively connected to the third current lead-out pipe 1C through the third connector 8C; the first current lead-out pipe 1A, the second current lead-out pipe 1B, and the third current lead-out pipe 1C are arranged side by side in this order along the longitudinal direction of the superconducting cable 7. A first temperature measuring optical fiber 73A embedded in the first superconducting layer 72A is connected with the first signal lead 2A; a second temperature measuring optical fiber 73B embedded in the second superconducting layer 72B is connected with the second signal lead 2B; a third temperature measuring optical fiber 73C embedded in the third superconducting layer 72C is connected with the third signal lead 2C; the first signal lead 2A, the second signal lead 2B and the third signal lead 2C are all optical fibers and are respectively arranged in the cavities of the first current leading-out tube 1A, the second current leading-out tube 1B and the third current leading-out tube 1C in a penetrating way, and can be led out through respective sealing covers (not shown).

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A terminal structure of a superconducting cable comprises a current leading-out pipe (1) arranged in a terminal sleeve (5), one end of the current leading-out pipe (1) is in conductive connection with a superconducting cable (7), the other end of the current leading-out pipe (1) is exposed from the end part of the terminal sleeve (5) to form an exposed end (12), a cavity (10) is arranged inside the current leading-out pipe (1), the terminal structure is characterized in that a leading-out hole (13) communicated with the cavity (10) is formed in the exposed end (12) of the current leading-out pipe (1), a sealing cover (4) is fixed on the leading-out hole (13), a signal lead (2) penetrates through the cavity (10) of the current leading-out pipe, and the tail end of the signal lead (2) is led out from the sealing cover (4).

2. A terminal structure of a superconducting cable according to claim 1, wherein the superconducting cable (7) includes a conductor layer (70) and an insulating layer (74) provided outside the conductor layer (70), an end portion of the superconducting cable (7) is located inside the terminal bushing (5), an end portion of the conductor layer (70) is exposed from the insulating layer (74), and the current lead-out tube (1) is connected to the conductor layer (70) through a connector (8).

3. A termination structure for a superconducting cable according to claim 2, wherein a voltage-equalizing jacket (9) is provided around the outside of said connector (8).

4. A termination structure for a superconducting cable according to claim 2, wherein said signal lead (2) is connected to a thermal resistor or thermocouple (3), said thermal resistor or thermocouple (3) being arranged at the end of the conductor layer (70) in the termination sleeve (5).

5. Terminal structure of a superconducting cable according to claim 4, characterized in that the signal lead (2) is connected to a pick-up module (61) located outside the sealing cover (4), the pick-up module (61) being in signal connection with a control module (66).

6. Terminal structure of a superconducting cable according to claim 5, characterized in that said acquisition module (61) is connected to a radio module (63), said control module (63) being connected to a reception module (65).

7. A termination structure for a superconducting cable according to claim 6, wherein the end of the termination sleeve (5) is provided with a grading ring (51), and the collection module (61) and the radio module (63) are arranged inside the grading ring (51).

8. A terminal structure of a superconducting cable according to claim 2, wherein the conductor layer (70) includes a supporting conductor (71) and a superconducting layer (72) made of a superconducting tape, the signal lead (2) is connected to a temperature measuring fiber (73), and the temperature measuring fiber (73) is wound outside the supporting conductor (71) in parallel with the superconducting tape.

9. Terminal structure of a superconducting cable according to claim 8, characterized in that the signal lead (2) is connected to a distributed optical fiber measurer (68) located outside the sealing cover (4).

10. The termination structure of a superconducting cable according to claim 8, wherein the superconducting layer (72) includes a first superconducting layer (72A), a second superconducting layer (72B) and a third superconducting layer (72C) which are coaxially arranged, and end portions of the first superconducting layer (72A), the second superconducting layer (72B) and the third superconducting layer (72C) are sequentially arranged in layers from inside to outside and are conductively connected to the first current lead-out tube (1A), the second current lead-out tube (1B) and the third current lead-out tube (1C), respectively; a first temperature measuring optical fiber (73A), a second temperature measuring optical fiber (73B) and a third temperature measuring optical fiber (73C) are respectively arranged in the first superconducting layer (72A), the second superconducting layer (72B) and the third superconducting layer (72C), and a first signal lead (2A), a second signal lead (2B) and a third signal lead (2C) which are connected with the first temperature measuring optical fiber (73A), the second temperature measuring optical fiber (73B) and the third temperature measuring optical fiber (73C) are respectively arranged in the cavities of the first current leading-out tube (1A), the second current leading-out tube (1B) and the third current leading-out tube (1C) in a penetrating manner; a first insulating layer (74A), a second insulating layer (74B) and a third insulating layer (74C) are provided outside the first superconducting layer (72A), the second superconducting layer (72B) and the third superconducting layer (72C), respectively.