JP7085956B2 - Superconducting cable termination connection and superconducting cable system - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Law (1) Website posting address http: // www. swcc. co. jp / cs / index. http Posting date March 2018 (2) Website posting address http: // www. swcc. co. jp / company / review / review 63. html Publication date March 2018 (3) Meeting name 12th IEEE International Conference (12th International Conference on the Properties and Applications of Dielectric Materials) Date May 21, 2018

The present invention relates to a superconducting cable termination connection and a superconducting cable system.

The present applicant has developed a terminal structure of a "polyphase coaxial type" superconducting cable in which a plurality of superconducting conductor layers are coaxially configured as a terminal connection portion of the superconducting cable, and has filed a prior application (Japanese Patent Application No. 2017). -126667).

In such a developed product, a double structure of an FRP inner pipe and a polymer outer pipe is adopted in a low temperature container in which the terminal portion of the superconducting cable is housed, and the refrigerant is circulated in the internal space of the FRP inner pipe. U-phase, V-phase, and W-phase current leads and shielded connection terminals (shielded electrodes) are arranged in each member of the FRP inner tube and the polymer outer tube so as to divide the current. It is assumed that the shield connection terminal is grounded outside the terminal part by pulling it out from.

“Ｄｅｖｅｌｏｐｍｅｎｔ ｏｆ ２２ ｋＶ ＨＴＳ Ｔｒｉａｘｉａｌ Ｓｕｐｅｒｃｏｎｄｕｃｔｉｎｇ Ｂｕｓ”（Ｋａｚｕｈｉｓａ Ａｄａｃｈｉ ｅｔ ａｌ．）， ＩＥＥＥ Ｔｒａｎｓａｃｔｉｏｎｓ ｏｎ Ａｐｐｌｉｅｄ Ｓｕｐｅｒｃｏｎｄｕｃｔｉｖｉｔｙ（ Ｙｅａｒ： ２０１７， Ｖｏｌｕｍｅ： ２７， Ｉｓｓｕｅ： ４） Ａｒｔｉｃｌｅ Ｓｅｑｕｅｎｃｅ Ｎｕｍｂｅｒ： ５４０１１０５ ＩＥＥＥ Ｊｏｕｒｎａｌｓ ＆ Ｍａｇａｚｉｎｅｓ

"Insulation performance" and "(electrical) insulation performance" are required for the external space between the FRP inner tube and the polymer outer tube.

As shown in Non-Technical Document 1, the applicant fills the external space with a heat insulating material (see III.A. Configuration of Triaxial Bus Termination), investigates the dependence of insulation on the degree of vacuum, and has a constant voltage. In order to guarantee the heat insulation performance and the heat insulation performance, it is concluded that the external space should be at atmospheric pressure (III.B. Insulation Test for Model Sample).

However, simply finding the condition of atmospheric pressure does not make it possible to construct a terminal that can satisfy both heat insulation performance and insulation performance, and it is still possible to create a configuration that can satisfy both performance. Not in.

A main object of the present invention is to provide a terminal connection portion of a superconducting cable and a superconducting cable system capable of simultaneously exhibiting heat insulating performance and insulating performance.

In order to solve the above problems, the inventors of the present invention further study a terminal connection portion of a superconducting cable capable of simultaneously exhibiting heat insulating performance and insulating performance, and between the FRP inner tube and the polymer outer tube. A solid insulator was filled in the external space of the above, and a constant AC / lightning impulse withstand voltage test and partial discharge test were performed (“Development of superconducting triaxial cable” 5-O-8 No.386. 12th IEEE International Conference on the Properties and Applications of Dielectric Materials --Xi'an --China, hereinafter referred to as "references"), newly found that it can withstand the withstand voltage test and that no partial discharge occurs. The invention was completed.

That is, according to one aspect of the present invention.
A terminal connection portion of a superconducting cable for accommodating a terminal portion of the superconducting cable having a superconducting conductor layer and a shield layer.
An inner accommodating pipe filled with a refrigerant for cooling the end portion of the superconducting cable, and an outer accommodating pipe arranged so as to surround the inner accommodating pipe.
Both the inner accommodating pipe and the outer accommodating pipe are arranged so as to be divided in the axial direction, and are connected to the superconducting conductor layer and the shield layer of the superconducting cable stripped inside the inner accommodating pipe, respectively. It has a lead electrode and a shield electrode that are electrically connected to the outside of the outer accommodating tube.
The space between the inner accommodating tube and the outer accommodating tube is provided with a terminal connection of a superconducting cable filled with a solid insulator under atmospheric pressure.

According to another aspect of the invention.
A superconducting cable having a superconducting conductor layer and a shield layer,
Provided is a superconducting cable system having a terminal portion of the superconducting cable inserted through and a terminal connection portion of the superconducting cable accommodating the terminal portion.

According to the present invention, since the space between the inner accommodation pipe and the outer accommodation pipe is filled with a solid insulator, convection of air in the space is suppressed (heat conduction is suppressed), and heat insulation is performed. Performance is demonstrated. In such a case, even if the space is filled with a solid insulator, the insulation performance is exhibited between the lead electrodes and between the lead electrodes and the shield electrodes under atmospheric pressure (see Examples).
From the above, according to the present invention, the heat insulating performance and the insulating performance can be exhibited at the same time.

It is a figure which shows typically the structure of the main part of the terminal connection part of a superconducting cable. It is sectional drawing which shows the schematic structure of the superconducting cable. It is a front view which shows the connection part of the superconducting cable in a lead electrode. FIG. 3 is a cross-sectional view taken along the line AA of FIG. It is sectional drawing of the solid insulator seen from the axial direction. It is a figure which shows typically the main part structure of the modification 1 of the terminal connection part of a superconducting cable. It is a figure which shows typically the main part structure of the modification 2 of the terminal connection part of a superconducting cable. It is a figure which shows typically the main part structure of the modification 3 of the terminal connection part of a superconducting cable. It is a figure which shows typically the main part structure of the modification 4 of the terminal connection part of a superconducting cable.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

First, the terminal connection portion of the superconducting cable to which the present invention is applied will be described.

<Structure of terminal connection part (1)>
FIG. 1 is a diagram schematically showing a configuration of a main part of a terminal connection portion 1 of a superconducting cable.
FIG. 1 is a side view showing a cross section other than the lead electrode 30, and here, for convenience of explanation, the side where the superconducting cable 10 is introduced is the base end side (right side in FIG. 1), and the opposite side is the tip side (FIG. 1). Then, it is explained as the left side and the insertion direction side).

The terminal connection portion 1 shown in FIG. 1 is a lead electrode 30 (30-1 to 30-3) in which the terminal portion of the superconducting cable 10 and the normal temperature portion, which is an external device of the terminal connection portion 1, function as a so-called current lead. ) Is used for connection.
The superconducting cable 10 has a plurality of superconducting conductor layers 112 (112-1 to 112-3). The terminal connection portion 1 has a plurality of lead electrodes 30 in order to connect the plurality of superconducting conductor layers 112 to the normal temperature portion.
Here, the terminal portion of the superconducting cable 10 is a cable core portion in which the heat insulating tube 12 is stripped off.

The terminal connection portion 1 mainly has a lead electrode 30 and a shield electrode 40, a low temperature container 20 having a refrigerant tank 21 and an outer tank 22, and a support leg portion 28.

In the terminal connection portion 1, lead electrodes 30 through which the superconducting cable 10 is inserted are arranged at predetermined intervals. A cylindrical inner accommodating pipe 211 is erected between the lead electrodes 30 so as to surround the superconducting cable 10, and a refrigerant tank 21 is formed. A cylindrical outer accommodating pipe 221 is erected between the lead electrodes 30 so as to surround the refrigerant tank 21, and the outer tank 22 is formed.

The low temperature container 20 has a double structure including an inner refrigerant tank 21 including a lead electrode 30 and an inner storage pipe 211, and an outer outer tank 22 including a lead electrode 30 and an outer storage pipe 221. The space between the inner accommodating pipe 211 and the outer accommodating pipe 221 is filled with the solid insulator 70 under atmospheric pressure.

The terminal portion of the superconducting cable 10 is inserted and accommodated in the low temperature container 20 (specifically, the refrigerant tank 21) configured in this way so as to extend horizontally in a predetermined state.
The "superconducting cable system" means a system in such a state, and is composed of a superconducting cable 10 and a terminal connection portion 1 into which a terminal portion thereof is inserted and accommodated.

At the terminal connection portion 1, the conductor current of the superconducting cable 10 is drawn from the low temperature container 20 to the actual system side of an external power device or the like as a normal temperature portion via the lead electrode 30 (specifically, the extraction terminal portion 37 in FIG. 3). On the other hand, the superconducting cable 10 is energized from the actual system side via the lead electrode 30.

The shield layer 114 (see FIG. 2) of the superconducting cable 10 is connected to the shield electrode 40, and the shield electrode 40 is grounded. The shield electrode 40 has a disk-shaped main body through which the superconducting cable 10 is inserted. The shield electrode 40 has the same function as the lead electrode 30, and the specific configuration will be described later.

The superconducting cable 10 has a plurality of layers of superconducting conductor layers made of superconducting wire, and a conductor current is drawn from the superconducting cable 10 via a lead electrode 30 for each superconducting conductor layer at the terminal connection portion 1.

<Superconducting cable (10)>
FIG. 2 is a cross-sectional view showing a schematic configuration of the superconducting cable 10.

As shown in FIGS. 1 and 2, the superconducting cable 10 has the superconducting conductor layer 112 (112-1 to 112-3) in the heat insulating tube 12 via the electrical insulating layer 113 (113-1 to 113-3). This is a superconducting cable in which a cable core 11 having a plurality of concentric cables is accommodated.

The superconducting cable 10 is a multi-phase superconducting cable in which currents having different phases are passed through the superconducting conductor layers 112. This is a three-phase coaxial type superconducting cable in which conductors that carry three-phase current are arranged coaxially.
The superconducting cable 10 may be configured to have two or four or more superconducting conductor layers, or may be configured to have a single layer of superconducting conductor layers.
The terminal connection portion 1 may also have a structure in which two or four or more superconducting conductor layers are connected to the normal temperature portion via the same number of lead electrodes 30, or a single-layer superconducting conductor layer is 1 The structure may be such that it is connected to a normal temperature portion via one lead electrode 30.

The cable core 11 has, in order from the center, a central cooling tube 111 that functions as an _N2 cooling tube, a first superconductor layer 112-1, a first electrical insulating layer 113-1 (conductor insulating layer), and a second superconductor layer 112-. 2. It has a second electrical insulating layer 113-2 (conductor insulating layer), a third superconducting conductor layer 112-3, a third electrical insulating layer 113-3 (conductor insulating layer), a shield layer 114, and a protective layer 115. There is.

The superconducting conductor layer 112 and the shield layer 114 are composed of, for example, a large number of superconducting tapes (tape-shaped superconducting wires) spirally wound around the outer surface of the lower layer.
The superconducting tapes constituting the superconducting conductor layer 112 are arranged so as not to overlap each other.

The superconducting tape here represents one or more elements selected from the _REBay Cu ₃ Oz system (RE represents Y, Nd, Sm, Eu, Gd and Ho, y ≦ 2 and _z = 6.2. It is an oxide superconducting material provided with a high-temperature superconducting thin film (up to 7).
This superconducting tape is produced by sequentially laminating an oxide superconducting conductor layer and a stabilizing layer, which are tape-shaped superconducting thin films, on an intermediate layer formed on a tape-shaped metal substrate.
The metal substrate of the superconducting tape is composed of, for example, nickel (Ni), nickel alloy or stainless steel.
The intermediate layer is, for example, a first layer made of an aluminum oxide (Al ₂ O ₃ ) layer, a gallium-doped zinc oxide layer (Gd ₂ Zr ₂ O ₇ : GZO), yttria-stabilized zirconia (YSZ), or the like on a metal substrate. A _second layer such as Y2O ₃ or lanthanum oxide (LaMnO ₃ ), a third layer composed of magnesium oxide (MgO) or the like, a fourth layer such as LaMnO ₃ and the like, and cerium oxide (CeO ₂ ). ) The fifth layer, which is a layer, is laminated in order.
The superconducting conductor layer is formed on the intermediate layer by the MOD method (Metal Organic Deposition Processes) without using a vacuum process using an organic metal salt or an organic metal compound as a raw material. .. In the MOD method, a thin film as a superconducting conductor layer is formed on a composite substrate by heating and thermally decomposing a metal organic acid salt on a composite substrate having an intermediate layer on the metal substrate. The stabilizing layer is formed by forming silver (Ag) or the like on the superconducting conductor layer.

The superconducting tape configured in this way is placed on the composite substrate with the central cooling tube 111 and the electrically insulating layer in the lower layer so that the superconducting conductor layer (superconducting thin film) is on the outer peripheral side and the composite substrate (board) is on the inner peripheral side. Each superconducting conductor layer 112 is configured by spirally winding around the outer circumference of 113 (113-1, 113-2).

The electrically insulating layer 113 is configured, for example, by winding a semi-synthetic insulating paper around the outer periphery of each of the lower superconducting conductor layers 112.
The protective layer 115 is configured by, for example, winding kraft paper or the like around the outer periphery of the shield layer 114.

As shown in FIG. 1, in the terminal portion of the superconducting cable 10, the cable core 11 is subjected to a step stripping process, and each layer is exposed in order from the tip side. Lead electrodes 30 (30-1 to 30-3) are electrically connected to each superconducting conductor layer 112 (112-1 to 112-3).

Here, the lead electrode 30 is arranged on the outer periphery of the superconducting conductor layer 112, and forms the refrigerant tank 21 and the outer tank 22 on at least one of the front and back surfaces of the inner accommodating pipe 211 and the outer accommodating pipe 221. Connected like this.

A shield electrode 40 is electrically connected to the outer periphery of the shield layer 114.
An electric field relaxation unit 15 such as a stress cone is arranged on the outer periphery of the electrically insulating layer 113 (113-1 to 113-3) arranged on the outer periphery of the superconducting conductor layer 112 (112-1 to 112-3). ..

The heat insulating pipe 12 is composed of an inner heat insulating inner pipe 121 and an outer heat insulating outer pipe 122, and the heat insulating inner pipe 121 and the heat insulating outer pipe 122 preferably have a corrugated shape. The heat insulating inner pipe 121 and the heat insulating outer pipe 122 are each composed of, for example, a corrugated pipe (corrugated pipe) made of stainless steel (SUS).

The superconducting cable 10 has a superconducting conductor layer 112 and a heat insulating pipe 12 having a double structure consisting of a heat insulating inner pipe 121 and a heat insulating outer pipe 122 in order on the outer peripheral side of the central cooling pipe 111, and has a double structure of heat insulation. A heat insulating material is arranged between the inner pipe 121 and the heat insulating outer pipe 122.

The heat insulating inner tube 121 is airtightly fixed to the inner peripheral portion of the shield electrode 40 on the base end side of the low temperature container 20 via the internal connecting portion 52.
The heat insulating inner pipe 121 airtightly communicates with the inside of the refrigerant tank 21 (mainly the inside of the inner accommodating pipe 211) via the inner peripheral portion of the shield electrode 40 to which the internal connecting portion 52 is fixed.

The heat insulating inner pipe 121 accommodates the cable core 11 and is connected to the refrigerant tank 21.
During operation of the superconducting cable system, the heat insulating inner pipe 121 is filled with a refrigerant (for example, liquid nitrogen), the superconducting conductor layer 112 is maintained in the superconducting state, and the heat insulating between the heat insulating inner pipe 121 and the heat insulating outer pipe 122 is for heat insulation. Is kept in a vacuum state.

The heat insulating outer tube 122 is airtightly fixed to the outer peripheral portion of the shield electrode 40 that functions as the proximal end surface of the outer tank 22 on the proximal end side of the low temperature container 20 via the external connecting portion 54.
A partition wall 56 is erected between the external connection portion 54 and the internal connection portion 52, and the space portion between the heat insulating outer pipe 122 and the heat insulating inner pipe 121 is the inside of the outer tank 22 (mainly the outer accommodating pipe 221). It is isolated from the inside of) and does not communicate.

<Inner storage pipe (211) and outer storage pipe (221)>
The inner accommodating tube 211 is an insulating tube made of FRP (Fiber Reinforced Plastics) having a tubular shape. That is, the terminal portion of the superconducting cable 10 is housed in the insulating pipe which is the refrigerant tank 21.
The inner accommodating pipe 211 has a heat insulating property as well as an insulating property.

The inner accommodating tubes 211 connected via the lead electrode 30 in the axial direction are formed through a through hole 322 (also referred to as “axial direction”) in the lead electrode 30 in the extending direction (also referred to as “axial direction”) of the superconducting cable 10. It is in a state of being communicated via (see FIG. 3).

During operation of the superconducting cable system, the refrigerant is circulated and supplied to the refrigerant tank 21 by a refrigerant circulation device (not shown), and the inside of the heat insulating inner pipe 121 communicating with the refrigerant tank 21 is also filled with the refrigerant.

The outer accommodating pipe 221 is a polymer brazing tube having a fold portion 223 on the outer periphery thereof, and is provided between the lead electrode 30 and between the lead electrode 30 and the shield electrode 40 so as to accommodate the refrigerant tank 21.
The outer accommodating pipe 221 is a tubular member made of, for example, an insulating material such as epoxy resin or FRP, and has folds 223 on the outer periphery thereof, and has insulating and heat insulating properties.
The outer accommodating tube 221 is airtightly fixed to the lead electrode 30.
The tubular body of the outer accommodating tube 221 is formed of FRP having high mechanical strength, and a polymer coating is integrally provided on the outer peripheral surface of the tubular body to provide folds 223. The polymer coating body, which is the fold portion 223, is made of a material having excellent electrical insulation performance, for example, a polymer material such as silicone polymer (silicone rubber), and has a plurality of umbrella-shaped folds separated in the longitudinal direction on the outer peripheral surface. It is composed.

The inside of the outer accommodating pipe 221 is in a state of communicating with the lead electrode 30 via a slot portion 364 (see FIG. 3) formed so as to penetrate in the extending direction of the superconducting cable 10.

When the electric field relaxation unit 15 is attached to the outer surface of the superconducting cable 10 in the refrigerant tank 21, the tubular body of the outer accommodation pipe 221 is arranged at a position surrounding the electric field relaxation unit 15 around the electric field relaxation layer.

<Solid insulator (70)>
The solid insulator 70 is a solid insulator filled in the space between the inner accommodating pipe 211 and the outer accommodating pipe 221.

The solid insulator 70 may be configured in any way as long as it has an insulating function and is arranged so as to be filled between the inner accommodating pipe 211 and the outer accommodating pipe 221. For example, the solid insulator 70 may be integrally formed. It may be composed of one layer, or may be composed of a single layer or a plurality of layers.
The solid insulator 70 is preferably made of a porous material having heat insulating properties and insulating properties.

FIG. 5 is a cross-sectional view of the solid insulator 70 seen from the axial direction.

As shown in FIG. 5, the solid insulator 70 is configured by laminating porous insulating sheets 71 (71-1 to 71-4) having insulating properties and flexibility.
It should be noted that one porous insulating sheet 71 may be arranged so as to be filled between the inner accommodating pipe 211 and the outer accommodating pipe 221 without laminating.

The porous insulating sheet 71 is a porous sheet-like member having a predetermined thickness in which a non-woven fabric glass fiber is impregnated with a porous material having a large number of fine pores and having high heat insulating properties.
The porous insulating sheet 71 is preferably, for example, a blanket obtained by impregnating a glass fiber non-woven fabric with airgel, particularly silica airgel. Silica airgel has a large number of pores with an average of 10 nm, and its thermal conductivity is 10 mW / m-K (38 ° C, 1 atm), which is the lowest thermal conductivity among solids and has extremely high heat insulation. It is known to have sex and to be extremely lightweight. It is preferable to use Pyrogel XT manufactured by Airgel Co., Ltd. as the porous insulating sheet 71.

The solid insulator 70 is formed by winding a porous insulating sheet 71 around the outer peripheral surface of the inner accommodating pipe 211 in a plurality of layers so as to cover the outer peripheral surface.
Each layer formed by the porous insulating sheet 71 is wound and fixed so as to have the same thickness.

In each layer formed by the porous insulating sheets 71-1 to 71-4, the ends 71a and 71b of the laminated porous insulating sheets 71-1 to 71-4 are positioned at positions shifted in the circumferential direction between the upper and lower layers. It is composed of being wound in such a way.
In each of the layers of the porous insulating sheets 71-1 to 71-4, the ends 71a and 71b of the overlapping layers are arranged at positions shifted by 180 ° with respect to the axis of the solid insulator 70. As a result, the ends 71a and 71b overlap in the radial direction between the inner accommodating pipe 211 and the outer accommodating pipe 221 to form a space that becomes an air pool, so that heat conduction is suppressed without convection of air. be able to.
The positions of the ends 71a and 71b of the porous insulating sheet 71 may be displaced many times around the axis of the solid insulator 70, for example, 30 °, 45 °, 90 °, 120 ° and the like. It may be deviated by the angle of. The ends 71a and 71b of the porous insulating sheet 71 are preferably arranged at positions where the joints of the layers overlap each other in the radial direction.

The porous insulating sheets 71-1 to 71-4 are wound around the outer periphery of the inner accommodating pipe 211 layer by layer, the ends 71a are abutted against each other and arranged in a cylindrical shape, and an insulating tape such as silicon tape is wound around the outer periphery. It is fixed in layers.
Here, in the porous insulating sheets 71-1 to 71-4, the portion where the ends 71b of the porous insulating sheet in the upper layer are abutted on the portion where the ends 71a of the porous insulating sheet 71 are butted against each other is formed. It is wound so that it is not positioned and is fixed with silicone tape. As a result, the porous insulating sheet 71 is filled in the space between the inner accommodating pipe 211 and the outer accommodating pipe 221 without shifting each layer.

The space between the inner accommodating pipe 211 and the outer accommodating pipe 221 is composed of at least the inner accommodating pipe 211, the outer accommodating pipe 221 and the lead electrode 30 and the shield electrode 40, and is maintained in the state of atmospheric pressure.

<Lead electrode (30)>
FIG. 3 is a front view showing a connection portion of a superconducting cable in the lead electrode 30, and FIG. 4 is a sectional view taken along line AA of FIG.

The lead electrode 30 shown in FIGS. 3 and 4 electrically connects the superconducting cable 10 to a device on the room temperature side via a drawer terminal portion 37.
Since the lead electrode 30 is similarly connected to each of the superconducting conductor layers 112 which is the outer peripheral surface of the superconducting cable 10, the lead electrode 30-2 of FIG. 1 will be described here as a representative example of the lead electrode 30. ..

The shield electrode 40 is a terminal through which the superconducting cable 10 is inserted at the central portion of the inner peripheral portion and is pulled out to the outside in order to ground the shield layer 114 of the superconducting cable 10, and is formed in the same manner as the lead electrode 30. Therefore, the shield electrode 40 will also be omitted in the description of the lead electrode 30.

In the terminal connection portion 1, the lead electrode 30 includes a superconducting conductor layer 112 located on the outer peripheral surface of the superconducting cable 10 inside the inner accommodating pipe 211 (refrigerant tank 21), and an external device on the normal temperature side of the outer accommodating pipe 221. Is conductive.

The lead electrode 30 has an electrode portion 32, a conductive lead portion 33, and a drawer terminal portion 37, and these members have conductivity and are electrically connected.
The electrode portion 32 is arranged on the outer periphery of the superconducting cable 10 and is connected to the superconducting cable 10. The electrode portion 32 is formed in a cylindrical shape by a conductive member such as copper, and is fixed in a state of being electrically connected to the superconducting conductor layer 112 on the outer periphery of the superconducting cable 10 on the inner peripheral surface.
As shown in FIG. 4, the electrode portion 32 is longer in the extending direction of the superconducting cable 10 than the thickness of the inner lead portion 34 and the outer lead portion 36. A plurality of through holes 322 through which the refrigerant passes, which are formed so as to penetrate along the axial direction, are provided in the peripheral wall portion of the electrode portion 32 in the circumferential direction.

The conductive lead portion 33 is arranged in a flange shape on the outer periphery of the electrode portion 32 and is electrically connected to the electrode portion 32. The conductive lead portion 33 is formed at a portion between the drawer terminal portion 37 and the electrode portion 32, and forms an energization path E from the drawer terminal portion 37 to the electrode portion 32.
The conductive lead portion 33 is an inner lead portion 34 arranged on the outer periphery of the electrode portion 32 and to which the inner accommodating tube 211 is fixed, and an outer lead electrically connected to the inner lead portion 34 and arranged on the outer periphery of the inner lead portion 34. It has a portion 36 and.

The inner lead portion 34 is a conductive member made of copper or the like in the shape of an annular plate, and the superconducting cable 10 and the electrode portion 32 are arranged inside. A multi-contact 35a, which is a contactor, is attached to the inner peripheral surface of the inner lead portion 34, and the inner lead portion 34 is electrically connected to the electrode portion 32 via the multi-contact 35a in the circumferential direction and in a state of being electrically connected. It is fitted so as to be slidable in the axial direction.
The inner lead portion 34 is airtightly fixed at the outer peripheral edge portion on the front and back surfaces so as to close the open end portion of the inner accommodating pipe 211. A fixing hole 342 for fixing the inner accommodating pipe 211 is formed in the outer peripheral edge portion of the inner lead portion 34, and the inner accommodating pipe 211 is fixed via the fixing hole 342 by a fastening material such as a bolt. It is preferable that the central axis of the inner accommodating pipe 211 and the central axis of the inner lead portion 34 are coaxial.

The outer lead portion 36 is formed in an annular shape by a conductive member such as copper, and here, the outer lead portion 36 is formed in the shape of an annular plate having the same thickness as the inner lead portion 34. A multi-contact 35b, which is a contactor, is attached to the inner peripheral surface of the outer lead portion 36, and the outer lead portion 36 is relatively connected to the inner lead portion 34 via the multi-contact 35b. It is slidably connected in the circumferential direction and the axial direction.
A drawer terminal portion 37 is provided on the outer peripheral surface of the outer lead portion 36 so as to project in the radial direction.
The drawer terminal portion 37 has a rectangular plate shape protruding from a part of the outer periphery of the outer lead portion 36, and is integrally formed with the outer lead portion 36.
The outer accommodating pipe 221 (see FIG. 1) is airtightly fixed to the outer lead portion 36 at the outer peripheral portion of at least one of the front and back surfaces. The outer accommodating pipe 221 is fixed to the outer lead portion 36 via a fixing hole 362 by a fastening member such as a bolt.
A cover 24, which is the tip surface of the outer tank 22, is airtightly fixed to the surface of the lead electrode 30-1 shown in FIG. 1 (here, the surface on the tip side), and the lead electrode 30-2 is on the front and back surfaces, respectively. The outer accommodating pipe 221 is attached.

The outer lead portion 36 has a slot portion 364 formed in a region inside the outer accommodating pipe 221 and between the drawer terminal portion 37 and the inner lead portion 34.
The slot portion 364 defines an energization path E for connecting the extraction terminal portion 37 and the electrode portion 32 in the conductive lead portion 33.
The slot portion 364 has a plurality of slots 364a and 364b arranged so as to surround the central superconducting cable 10.
The slot portion 364 determines the length of the energization path E between the outlet terminal portion 37 and the contact portion between the superconducting cable 10 of the electrode portion 32, and the contact between the drawer terminal portion 37 and the superconducting cable 10 of the electrode portion 32. It is specified to be longer than the straight line connecting the parts at least at the shortest.
The slots 364a and 364b are concentric and have different diameters in a missing circle (a shape obtained by cutting a part of a circle with a straight line). The end portion of the slot 364a on the outermost peripheral side that sandwiches the missing circle portion is arranged at a position on the opposite side of the drawer terminal portion 37 and the superconducting cable 10 in the radial direction.

In the concentric slots 364b having different diameters with respect to the slot 364a and adjacent to each other on the inner peripheral side, the end portion sandwiching the missing circle portion of the slot 364b is sandwiched with the end portion sandwiching the missing circle portion in the slot 364a. It is positioned on the opposite side and at a position facing the connection portion of the extraction terminal portion 37 with the slot 364a sandwiched between them.
In these plurality of missing circle-shaped slots 364a and 364b, the ends of the adjacent slots sandwiching the missing circle portion are arranged on opposite sides of the concentric portions.

In the lead electrode 30, the heat conduction path is lengthened by locating the missing circle portion of the outermost slot 364a closest to the drawer terminal portion 37 in the direction facing the drawer terminal portion 37. As a result, as compared with the configuration in which the lead electrode 30 is formed so that the missing circle portion of the outermost peripheral slot 364a closest to the drawer terminal portion 37 is arranged on the drawer terminal portion 37 side, the external dimensions are the same. The amount of heat penetration can also be reduced with the lead electrode.
Here, the "length / cross-sectional area ratio" of the energization path E (the conductive portion in which the conduction heat is conducted in the inner lead portion 34 and the outer lead portion 36 between the drawer terminal portion 37 and the electrode portion 32) is set. The amount of heat penetration (sum of conduction heat and Joule heat generation when energized) is set to the minimum value.

The drawer terminal portion 37 is provided so as to project outward from the outer peripheral surface of the conductive lead portion 33, that is, the outer peripheral surface of the outer lead portion 36, and protrude outward from the outer peripheral surface of the outer tank 22, and is arranged on the room temperature side.

<Summary>
In the above embodiment, the terminal connection portion 1 in which the superconducting conductor layer 112 and the shield layer 114 of the superconducting cable 10 are connected to the lead electrode 30 and the shield electrode 40, respectively, is provided, and the inner accommodating tube 211 surrounding the superconducting cable 10 is provided. The space between the outer accommodating pipe 221 and the outer accommodating pipe 221 is filled with a solid insulator 70 (porous insulating sheet 71) in a state of atmospheric pressure.

According to such a configuration, since the porous insulating sheet 71 is filled in the space portion, the convection of air in the space portion is suppressed (heat conduction is suppressed), and the heat insulating performance is exhibited. Even if the space is filled with the porous insulating sheet 71, the insulating performance is exhibited between the lead electrode 30 and between the lead electrode 30 and the shield electrode 40 under atmospheric pressure (see Examples).
From the above, according to the terminal connection portion 1 of the superconducting cable according to the present embodiment, the heat insulating performance and the insulating performance can be exhibited at the same time.

In the terminal connection portion 1 of the superconducting cable, the solid insulator 70 is composed of the porous insulating sheets 71-1 to 71-4, but instead of this, between the inner accommodating pipe 211 and the outer accommodating pipe 221. The space may be filled with glass wool or other known heat insulating material.

Glass wool is a fiber having heat insulating properties, and is made by blowing off glass melted at a high temperature by centrifugal force or the like and finely fiberizing it into cotton-like fibers.

If the solid insulator 70 is made of glass wool, the same action and effect as described above can be obtained, and recycled glass can be used as the glass to be used, which can improve economic efficiency and environmental friendliness.

<Modifications 1 to 4>
6 to 9 are diagrams schematically showing the main components of the terminal connection portions 1A to 1D according to the modified examples 1 to 4 of the terminal connection portion 1 of the superconducting cable.
Note that FIGS. 6 to 9 are side views having a cross section other than the lead electrode 30 as in FIG. 1, and here, for convenience of explanation, the side where the superconducting cable 10 is introduced is the base end side (FIGS. 6 to 9). In FIG. 9, the right side will be described, and the opposite side will be described as the tip side (the left side in FIGS. 6 to 9 and the insertion direction side).

The terminal connection portions 1A to 1D shown in FIGS. 6 to 9 have a different configuration of the solid insulator 70 as compared with the terminal connection portion 1 shown in FIG. 1, and have the same basic configuration other than that. Therefore, in FIGS. 6 to 9, the same components are designated by the same reference numerals, and the description thereof will be omitted.

<Modification 1>
In the terminal connection portion 1A of the superconducting cable shown in FIG. 6, the solid insulator 70 is made of an FRP vacuum body 72 (FRP: Fiber-Reinforced Plastics).

In the terminal connection portion 1A of the superconducting cable, the space between the lead electrode 30 (30-1 to 30-3) arranged in the axial direction and the lead electrode 30-shield electrode 40 between the inner accommodating tube 211 and the outer accommodating tube 221. The portion is filled with a vacuum body 72 made of FRP in a state of atmospheric pressure.

Each FRP vacuum body 72 is a cylindrical body having a vacuum inside.
In each FRP vacuum body 72, there is no gap in the space between the lead electrode 30 (30-1 to 30-3) and between the lead electrode and the shield electrode 40 between the inner accommodating tube 211 and the outer accommodating tube 221. It is arranged in a filled state.

According to the above modification 1, the lead electrode 30 (30-1 to 30-3) and the lead electrode 30-shield electrode 40 are appropriately insulated and insulated by the FRP vacuum body 72, respectively. It is possible to obtain the same effect as that of the terminal connection portion 1.
In the first modification, the porous insulating sheet is formed in the space between the inner accommodating pipe 211 and the outer accommodating pipe 221 other than the region occupied by the FRP vacuum body 72 (when a gap is formed). 71, glass wool or other known heat insulating material may be filled.

<Modification 2>
In the terminal connection portion 1B of the superconducting cable shown in FIG. 7, the solid insulator 70 is composed of the solid insulator 74.
The solid insulator 74 is composed of a metal vacuum body 742 whose inside is evacuated and a metal shaft 744.

The metal vacuum body 742 is a space between the lead electrodes 30 (30-1 to 30-3) arranged in the axial direction and between the lead electrodes 30 and the shield electrodes 40, between the inner accommodation pipe 211 and the outer accommodation pipe 221. Is located in.

The metal vacuum body 742 cantilevered with respect to one of the lead electrodes 30 (30-1 to 30-3) adjacent in the axial direction to the lead electrode 30 and the shield electrode 40 via a shaft 744 having conductivity. It is connected in a state and is arranged so as to be separated from the other lead electrode 30.
For example, the metal vacuum body 742 arranged between the lead electrodes 30-1 and 30-2 is connected to the lead electrode 30-2 in a state of being close to the lead electrode 30-1 but not in contact with the lead electrode 30-1.

According to the above modification 2, the U-phase, V-phase, and W-phase lead electrodes 30 (30-1 to 30-3) are appropriately insulated and insulated from each other, and have the same effect as the terminal connection portion 1. Can be played.

In the second modification, the metal vacuum body 742 in the terminal connection portion 1B may be replaced with a fiber reinforced plastic tube (vacuum FRP tube) whose inside is evacuated.
Also in the second modification, there is a (gap) in the space between the inner storage pipe 211 and the outer storage pipe 221 other than the region occupied by the solid insulator 74, a porous insulating sheet 71, glass wool and other known materials. Insulation may be filled.

<Modification 3>
In the terminal connection portion 1C of the superconducting cable shown in FIG. 8, the solid insulator 70 is composed of an insulating unit 76.

The insulation unit 76 is arranged in the space between the inner accommodating pipe 211 and the outer accommodating pipe 221 between the lead electrodes 30 (30-1 to 30-3) arranged in the axial direction and between the lead electrodes 30 and the shield electrode 40. It is a tubular unit that is made.

The insulation unit 76 insulates between the lead electrodes 30 (30-1 to 30-3) arranged in the axial direction and between the lead electrodes 30 and the shield electrode 40, and is a space portion between the inner accommodation pipe 211 and the outer accommodation pipe 221. Insulate.

The insulating unit 76 has an insulating portion 766 that insulates between the metal vacuum bodies 762 and 762, the metal shafts 764 and 764, and the metal vacuum bodies 762 and 762.

The metal vacuum bodies 762 and 762 are hollow metal tubular bodies with a vacuum inside.

In the metal vacuum bodies 762 and 762, the lead electrodes 30 (30-1 to 30-3) and the shield electrodes 40 arranged in the axial direction sandwiching the insulating unit 76 are provided via conductive shafts 764 and 764. They are connected so as to project from both sides in the directions facing each other.

A plurality of shafts 764 and 764 are connected between the positions of the metal vacuum bodies 762 and 762 at predetermined intervals in the circumferential direction and the facing lead electrodes 30 (for example, 30-2 and 30-3). There is.
The shafts 764 and 764 support the metal vacuum bodies 762 and 762 on both of the lead electrodes 30 (for example, 30-2 and 30-3) in a cantilevered state.

The insulating portion 766 is interposed between the metal vacuum bodies 762 and 762, and insulates between the metal vacuum bodies 762 and 762.
The insulating portion 766 is a tubular body made of FRP having a peripheral wall having an H-shaped cross section, and the metal vacuum bodies 762 and 762 are inserted and fixed in the recesses opened at both ends in a connected state. There is.

As a result, the opposing portions of the metal vacuum bodies 762 and 762 are covered with the insulating portion 766, and the metal vacuum bodies 762 and 762 are held in a state of not conducting each other.

The insulation unit 76 is provided in a space between the lead electrodes 30 (30-1 to 30-3) arranged in the axial direction and between the lead electrodes 30 and the shield electrode 40, between the inner accommodation pipe 211 and the outer accommodation pipe 221. It is filled under atmospheric pressure.

According to the above modification 3, since the inside of the metal vacuum bodies 762 and 762 of the insulating unit 76 is in a vacuum state, the space between the inner accommodation pipe 211 and the outer accommodation pipe 221 is vacuum-insulated. Insulation performance is demonstrated in the space. Since the metal vacuum bodies 762 and 762 are connected to the lead electrode 30 and the shield electrode 40 via the shafts 764 and 764, they have the same potential as these members, but the metal vacuum bodies 762 and 762 are made of FRP. Since the insulating portion 766 is interposed, the lead electrode 30 and the lead electrode 30-shield electrode 40 are insulated from each other, and the insulating performance is exhibited in the space.
Therefore, even in the modified example 3, the heat insulating performance and the insulating performance can be exhibited at the same time.

<Modification example 4>
In the terminal connection portion 1D of the superconducting cable shown in FIG. 9, the solid insulator 70 is composed of an insulating unit 76 and a heat insulating material 78.
The insulation unit 76 of the terminal connection portion 1D is the same as that of the terminal connection portion 1C according to the modification 3.
The heat insulating material 78 is made of a porous insulating sheet 71, glass wool and other known heat insulating materials, and is made of glass wool here.
The heat insulating material 78 is a space between the inner accommodating pipe 211 and the outer accommodating pipe 221 and is filled in a portion other than the area occupied by the insulating unit 76.
In the terminal connection portion 1D, the heat insulating material 78 is wound around the outer periphery of the inner accommodating pipe 211 to a predetermined thickness, and after the insulating unit 76 is installed, the heat insulating material 78 is further wound around the outer periphery of the insulating unit 76 to form the outer accommodating pipe 221. It is preferable to stack until the thickness is such that it abuts on the inner circumference. At this time, it is preferable that the joints (the portions where both ends abut) of the heat insulating material 78 are arranged at positions shifted in the radial direction.

According to the above modification 4, the portion of the space between the inner accommodating pipe 211 and the outer accommodating pipe 221 other than the region occupied by the insulating unit 76 is filled with the heat insulating material 78. Air convection is suppressed and heat conduction is suppressed.
Therefore, in the modified example 4, the heat insulating performance can be further improved.

(1) Sample production (1.1) Examples 1 and 2
The terminal connection portion 1 of FIG. 1 was manufactured as the terminal connection portion of Examples 1 and 2.
In the terminal connection portion 1 of the first embodiment, between the lead electrodes 30-1 to 30-3, between the lead electrodes 30-3 and the shield electrode 40, and between the inner accommodating pipe 211 and the outer accommodating pipe 221. The solid insulator 70 arranged between the two was made of a porous heat insulating sheet 71 (pyrogel XT).
In the terminal connection portion 1 of the second embodiment, the solid insulator 70 is made of glass wool.

(1.2) Example 3
The terminal connection portion 1D of FIG. 9 was manufactured as the terminal connection portion of the third embodiment.
In the terminal connection portion 1D of Example 3, the solid insulator 70 is composed of an insulating unit 76 and a heat insulating material 78 (glass wool).

(1.3) Comparative Example 1
As the terminal connection portion of Comparative Example 1, the terminal connection portion without the solid insulator 70 was manufactured in the configuration of the terminal connection portion 1 of the first embodiment.

(2) Insulation performance test and insulation performance test In Examples 1 to 3 and Comparative Example 1, the following insulation performance test and insulation performance test were carried out in order to confirm the insulation performance and insulation performance, respectively.
In the adiabatic performance test, the amount of heat penetration was measured by the calorimetric method.
In the insulation performance test, liquid nitrogen (77K, 0.3MPa) is sealed inside the refrigerant tank 21 using a 5m superconducting cable, and it is used as CIGRE TB538 (recommended test standard by the International Conference on High Voltage and High Power Systems). Based on insulation tests were performed (see References III. INSULATION DESIGN OF THE TRIAXIAL TERMINATION and IV. THE TEST OF TRIAXIAL SUPERCONDUCTING CABLE SYSTEM).
The table shows the measurement results of the heat penetration amount based on the heat insulation performance test, and the commercial frequency withstand voltage test (commercial AC), lightning impulse withstand voltage test (lightning impulse) and commercial frequency partial discharge test (partial discharge) based on the insulation performance test. Shown in 1.

(3) Summary In the heat insulation performance test, the heat penetration amount was large and the heat insulation performance was inferior in Comparative Example 1, whereas the heat penetration amount was suppressed to be low in Examples 1 to 3.
In the insulation performance test, Comparative Example 1 and Examples 1 and 2 can withstand 52 kV application for 30 minutes in the commercial frequency withstand voltage test, and can withstand 10 repetitions of ± 125 kV application in the lightning impassle withstand voltage test. In the commercial frequency partial discharge test, no partial discharge occurred when 36 kV was applied (noise level was 5 pC or less).
Example 3 can withstand 26 kV application for 30 minutes in the commercial frequency withstand voltage test, can withstand 10 repetitions of ± 75 kV application in the lightning impass withstand voltage test, and withstand 19 kV application in the commercial frequency partial discharge test. No partial discharge occurred (noise level was 5 pC or less).
As described above, from the comparison between Comparative Example 1 and Examples 1 to 3, it is possible to fill the space between the inner accommodating pipe 211 and the outer accommodating pipe 221 with the solid insulator 70 in the state of atmospheric pressure. It can be seen that it is useful for exerting heat insulation performance and insulation performance. In particular, from the comparison between Example 1 and Examples 2 and 3, the insulation performance when the solid insulator 70 is made of the porous heat insulating sheet 71 (Example 1) and the case where it is made of glass wool (Example 2). ), It can be seen that it has both advantages of the heat insulating performance when composed of the insulating unit 76 and glass wool (Example 3).

As described above, the embodiments and examples disclosed herein should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1, 1A, 1B, 1C, 1D Superconducting cable terminal connection 10 Superconducting cable 11 Cable core 12 Insulation tube 15 Electricity relaxation part 20 Low temperature container 21 Refrigerator tank 22 Outer tank 24 Cover 30 Lead electrode 32 Electrode part 33 Conductive lead part 34 Inner lead 35a, 35b Multi-contact 36 Outer lead 37 Drawer terminal 40 Shield electrode 52 Internal connection 54 External connection 56 Partition 70 Solid insulator 71 Porous insulation sheet 72 FRP vacuum body 74 Metal vacuum body 76 Insulation Unit 78 Insulation material 111 Central cooling pipe 112 Superconducting conductor layer 113 Electrical insulation layer 114 Shield layer 115 Protective layer 121 Insulation inner pipe 122 Insulation outer pipe 211 Inner accommodation pipe 221 Outer accommodation pipe 223 Folds 322 Through hole 742 Metal vacuum body 744 Shaft 762 Metal vacuum body 764 Shaft 766 Insulation

Claims (6)

A terminal connection portion of a superconducting cable for accommodating a terminal portion of the superconducting cable having a superconducting conductor layer and a shield layer.
An inner accommodating pipe filled with a refrigerant for cooling the end portion of the superconducting cable, and an outer accommodating pipe arranged so as to surround the inner accommodating pipe.
Both the inner accommodating pipe and the outer accommodating pipe are arranged so as to be divided in the axial direction, and are connected to the superconducting conductor layer and the shield layer of the superconducting cable stripped inside the inner accommodating pipe, respectively. It has a lead electrode and a shield electrode that are electrically connected to the outside of the outer accommodating tube.
The terminal connection portion of the superconducting cable, in which the space between the inner accommodating pipe and the outer accommodating pipe is filled with a solid insulator under atmospheric pressure. The terminal connection portion of the superconducting cable according to claim 1, wherein the solid insulator is a porous insulating sheet made of a porous material and having flexibility. The terminal connection portion of the superconducting cable according to claim 1, wherein the solid insulator is glass wool. The solid insulator includes a metal vacuum body connected to each of the lead electrodes and shield electrodes facing each other, or the lead electrodes facing each other, and the facing protruding ends of the metal vacuum body. The terminal connection portion of the superconducting cable according to claim 1, further comprising an insulating unit having an insulating portion interposed between the protrusions to insulate the protrusions from each other. The terminal connection portion of the superconducting cable according to claim 4, wherein the solid insulator has the insulating unit and a heat insulating material that fills the space portion. A superconducting cable having a superconducting conductor layer and a shield layer,
A superconducting cable system having a terminal connection portion of the superconducting cable according to any one of claims 1 to 5, wherein an end portion of the superconducting cable is inserted and accommodated therein.

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