WO2016088446A1 - Superconducting cable and cable core for superconducting cable - Google Patents

Abstract

Provided are: a superconducting cable that makes it possible to prevent damage to a heat-insulating pipe during an accident such as a ground fault; and a cable core for a superconducting cable. The cable core for a superconducting cable is provided with a superconducting conductor layer, a ground layer provided to the outer circumference of the superconducting conductor layer with an electrically insulating layer therebetween, and a protective layer provided to the outer circumference of the ground layer. The protective layer comprises an arc-resistant layer configured from one or more materials selected from among high-performance and highly functional fibers, polypropylene resins, polyethylene resins, polytetrafluoroethylene resins, silicone resins, amino resins, aramid resins, polyphenylene sulfide resins, polyimide resins, polyacrylate resins, silicone rubbers, and metal.

Description

Superconducting cable and cable core for superconducting cable

The present invention relates to a superconducting cable used for a power transmission path and the like, and a cable core housed in a heat insulating tube and used for the superconducting cable. In particular, the present invention relates to a superconducting cable and a cable core for a superconducting cable that can prevent the insulation pipe from being damaged in the event of an accident such as a ground fault.

The superconducting cable is expected as an energy-saving technology because it is small and can transmit a large amount of power with low loss. A typical superconducting cable includes a cable core having a superconducting conductor layer, and a heat insulating tube that houses the cable core and is filled with a liquid refrigerant such as liquid nitrogen that maintains the superconducting conductor layer in a superconducting state. Superconducting cables include single-core cables in which only one cable core is accommodated in one heat insulation tube, and multi-core batch cables in which a plurality of cable cores are accommodated in one heat insulation tube (Patent Document 1). .

The cable core typically mechanically protects the former, the superconducting conductor layer, the electrical insulating layer, the outer superconducting layer that is grounded and used as a shield layer, and the outer superconducting layer in order from the inside. A protective layer (Patent Document 1). The said heat insulation pipe | tube is a vacuum heat insulation pipe | tube of a double structure provided with an inner tube and an outer tube | pipe typically (patent document 1). A metal pipe such as a stainless steel pipe is used for the inner pipe and the outer pipe.

In addition, Patent Document 1 discloses that a former supporting a superconducting conductor layer is made of a normal conducting material such as copper in order to divert an accident current in the event of an accident such as a short circuit or a ground fault.

JP 2013-044564 A

It is desirable to be able to prevent damage to the insulation pipe when an accident such as a ground fault occurs in the superconducting cable itself.

Patent Document 1 discloses a configuration that allows an accident current to flow when an accident such as a short circuit or a ground fault occurs as described above. This accident current is assumed to be an excessive current that can flow instantaneously to a superconducting cable due to a short circuit accident that occurs in a normal conducting cable such as an overhead power transmission line that can be laid around the superconducting cable. Yes. The above configuration is for flowing the excessive current on the assumption that the superconducting cable itself is healthy. Since an accident such as a ground fault can occur in the superconducting cable itself, countermeasures are desired.

If an accident such as a ground fault occurs in the superconducting cable itself and an electrical breakdown occurs, an arc can occur from the superconducting conductor layer that is at high potential to the grounding layer such as the outer superconducting layer that is grounded to zero potential There is sex. When this arc reaches the inner tube of the heat insulating tube, there is a possibility that a hole is opened in the inner tube. If a hole is made in the inner tube, the liquid refrigerant leaks into the vacuum heat insulating layer formed between the inner tube and the outer tube, making it impossible to maintain the vacuum, or the liquid refrigerant is vaporized and insulated by the volume expansion at the time of vaporization. The tube may be damaged. In addition, the arc discharge described above may cause a hole in the outer tube as well as the inner tube.

Furthermore, in the case of a multi-core cable as described in Patent Document 1, the cable cores housed in one heat insulating tube are close to each other. Therefore, when a certain cable core breaks down and an arc is generated among a plurality of cable cores housed in one heat insulating tube, the arc may jump to adjacent cable cores, and the cable cores may be short-circuited. .

Therefore, one of the objects of the present invention is to provide a superconducting cable and a cable core for the superconducting cable that can prevent the insulation pipe from being damaged when an accident such as a ground fault occurs in the superconducting cable itself.

A cable core for a superconducting cable according to an aspect of the present invention includes a superconducting conductor layer, a ground layer provided on an outer periphery of the superconducting conductor layer via an electrical insulating layer, and a protective layer provided on the outer periphery of the ground layer. Prepare.
The protective layer is made of high performance / high performance fiber, polypropylene resin, polyethylene resin, polytetrafluoroethylene resin, silicone resin, amino resin, aramid resin, polyphenylene sulfide resin, polyimide resin, polyacrylate resin, silicone rubber and metal. Including an arc resistant layer comprised of one or more selected materials.

A superconducting cable according to an aspect of the present invention includes the above-described cable core for a superconducting cable and a heat insulating tube that houses the cable core for the superconducting cable.

When a superconducting cable is constructed by housing the above-mentioned superconducting cable core in a heat insulating tube, the superconducting cable can prevent the heat insulating tube from being damaged in the event of a ground fault or the like.

∙ The above superconducting cable can prevent the insulation pipe from being damaged in the event of a ground fault.

2 is a transverse cross section showing an outline of the superconducting cable of the first embodiment.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.
(1) A cable core for a superconducting cable according to an aspect of the present invention includes a superconducting conductor layer, a grounding layer provided on the outer periphery of the superconducting conductor layer via an electrical insulating layer, and a protection provided on the outer periphery of the grounding layer. And a layer.
The protective layer is made of high performance / high performance fiber, polypropylene resin, polyethylene resin, polytetrafluoroethylene resin, silicone resin, amino resin, aramid resin, polyphenylene sulfide resin, polyimide resin, polyacrylate resin, silicone rubber and metal. It includes an arc resistant layer composed of one or more selected materials (hereinafter sometimes referred to as a high arc resistant material).

Examples of the high-performance and high-function fiber include high-strength fiber, high-strength and high-modulus fiber, high heat-resistant fiber, and non-combustible fiber. Examples of the high-strength fiber include non-metallic fibers having a tensile strength of about 1 GPa or more. Examples of the high strength / high elastic modulus fiber include non-metallic fibers having a tensile strength of about 2 GPa or more and an elastic modulus of about 50 GPa or more, which are called super fibers. Examples thereof include inorganic fibers composed of non-metallic inorganic materials such as carbon, ceramics such as glass and metal compounds, and organic fibers composed of organic materials such as resins.

The cable core for the above superconducting cable has an arc resistant layer containing a specific high arc resistant material on the outer periphery of the grounding layer. Therefore, the superconducting cable is housed in a heat insulating tube to form a superconducting cable. When it occurs, it is possible to prevent the insulation pipe from being damaged by the arc resulting from this accident. Specifically, even if the electric insulation layer breaks down and an arc is generated from the superconducting conductor layer to the ground layer, an arc-resistant layer is interposed between the ground layer and the heat insulation tube. Can be substantially blocked by the arc-resistant layer. Therefore, the cable core for a superconducting cable can prevent damage to the heat insulating pipe such as a hole formed in the heat insulating pipe due to an arc generated at the time of an accident such as a ground fault that may occur in the superconducting cable.

In the case of a multi-core cable in which a plurality of the above-mentioned superconducting cable cores are housed in one heat insulating tube, an arc-resistant layer is interposed between adjacent cores. Therefore, it is possible to prevent adjacent cores from being short-circuited by an arc from one core provided in the multi-core cable.

(2) As an example of the cable core for the superconducting cable, there is a form in which the arc-resistant layer includes a wound layer formed by winding a tape material composed of the material (high arc-resistant material).

The above form can easily form an arc-resistant layer and is excellent in manufacturability. The winding layer has a multilayer structure in which the tape material is wound with a gap, and includes layers with different winding directions, that is, includes an S winding layer and a Z winding layer, so that the winding to the heat insulating tube and the adjacent cable core can be performed. While preventing arc discharge, a liquid refrigerant impregnation path can be secured, and the superconducting cable can be manufactured with excellent productivity.

(3) As an example of the cable core for the superconducting cable, the arc-resistant layer has a multilayer structure composed of a plurality of different materials, and from a semi-synthetic paper containing polypropylene resin and kraft paper in order from the inner peripheral side. Examples include a semisynthetic paper layer to be formed, an inorganic fiber layer formed from at least one of glass fiber and ceramic fiber, and an organic fiber layer formed from aramid fiber.

In addition to contributing to the construction of a superconducting cable that can prevent damage to the heat insulation pipe at the time of an accident such as a ground fault as described above, the above embodiment has the following effects.
(A) The lower grounding layer can be pressed, smoothed or protected by the semi-synthetic paper layer, and an inorganic fiber layer can be easily formed.
(B) When an inorganic fiber layer composed of at least one of glass fiber and ceramic fiber, which is one of highly arc-resistant materials having excellent arc resistance, is provided, the arc resistance is excellent. As a result, the total thickness of the arc resistant layer can be reduced, and the core diameter can be reduced. In particular, since ceramic fibers have better arc resistance than glass fibers, when an arc-resistant layer containing ceramic fibers is provided, arc resistance is further improved, and the core can be further reduced in diameter. Be expected. When an inorganic fiber layer composed of both glass fibers and ceramic fibers is provided, it is expected to be more excellent in arc resistance.
(C) Aramid fiber, which is one of high arc-resistant materials, has high strength, and mechanical strength can be increased by providing an organic fiber layer made of aramid fiber. This organic fiber layer can function as a high-strength layer described later.

(4) As an example of the cable core for the superconducting cable, the arc-resistant layer includes a high-strength layer composed of fibers having a tensile strength of 1 GPa or more among the high-performance and high-function fibers. It is done.

The above-mentioned configuration can contribute to the construction of a superconducting cable that can prevent damage to the heat insulation pipe at the time of an accident such as a ground fault by providing an arc-resistant layer including a specific high arc-resistant material, and also can withstand arc. By providing a high-strength layer in at least a part of the layer, the strength is also excellent. In particular, when the high-strength layer is made of a fiber having a strength sufficient to withstand the tension when the above-described superconducting cable core is pulled into the heat insulating tube, the high-strength layer is a tension member for pulling in the high-strength layer. Available to: Since the arc-resistant layer can also be used as a tension member and another high-tensile material can be omitted or the constituent material of the high-tensile material can be reduced, the above form is excellent in superconducting cable manufacturability and the like.

(5) A superconducting cable according to an aspect of the present invention includes the cable core for a superconducting cable according to any one of the above (1) to (4), and a heat insulating tube for housing the cable core for the superconducting cable. Prepare.

Since the above superconducting cable is at least one cable core housed in a heat insulating tube, preferably all the cable cores are the above-mentioned superconducting cable cable cores having the specific arc-resistant layer, as described above. When an accident such as a ground fault occurs in itself and an arc is generated from the superconducting conductor layer to the heat insulating tube, damage to the heat insulating tube due to the arc can be prevented by the arc resistant layer including a specific high arc resistant material. As described in (3) above, when the arc resistant layer includes a specific inorganic fiber layer, the arc resistance is superior. As described in the above (3) or (4), when the arc-resistant layer includes a high-strength layer, at least a part of the arc-resistant layer can be used for the above-mentioned pulling-in tension member, etc. Superconducting cables are excellent in manufacturability and installation workability.

(6) As an example of the superconducting cable, a form in which the heat insulating pipe is provided with a plurality of cable cores for the superconducting cable can be given.

The above form is a multi-core cable. The said form is a cable core for superconducting cables with which each cable core accommodated in one heat insulation pipe | tube is equipped with the arc-resistant layer containing the above-mentioned specific high arc-resistant material. Therefore, even if one of the plurality of superconducting cable cable cores housed in the heat insulating tube breaks down and an arc is generated from the superconducting conductor layer to the ground layer, the above configuration is adjacent. Since the arc-resistant layer is interposed between the cores to be performed, adjacent cores can be prevented from being short-circuited.

[Details of the embodiment of the present invention]
Hereinafter, specific examples of embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
With reference to FIG. 1, the superconducting cable 1 provided with the cable core 10 for superconducting cables of Embodiment 1 is demonstrated.
Overall Configuration As shown in FIG. 1, the superconducting cable 1 of Embodiment 1 includes a superconducting cable core 10 (hereinafter, simply referred to as a cable core 10 or a core 10) including a superconducting conductor layer 12, and a plurality of superconducting cables 1. It is a multi-core collective cable provided with the heat insulation pipe | tube 20 which accommodates the core 10 (here 3 core collective cable). Superconducting cable 1 is laid to construct a power transmission path.

Each cable core 10 has the same configuration, and includes a former 11, a superconducting conductor layer 12, an electric insulating layer 13, a ground layer 14, and a protective layer 15 in order from the center. The heat insulating tube 20 is a double structure vacuum heat insulating tube including an inner tube 21 and an outer tube 22. The superconducting cable 1 is a low-temperature insulation type cable in which both the superconducting conductor layer 12 and the electrical insulating layer 13 are accommodated in a heat insulating tube 20 and cooled by a liquid refrigerant L such as liquid nitrogen. The basic configuration of the superconducting cable 1 is similar to a conventional superconducting cable. The superconducting cable 1 of the first embodiment is characterized in that the protective layer 15 includes an arc resistant layer made of a specific material (high arc resistant material). Hereinafter, functions and representative configurations of each element will be briefly described, and the protective layer 15 will be described in detail.

-Cable core for superconducting cable-Former The former 11 is a support member that supports the superconducting conductor layer 12. Specific examples include a solid body such as a hollow body such as a pipe, a twisted wire obtained by twisting a plurality of metal strands, and a twisted product obtained by further twisting a plurality of twisted wires. Main constituent materials include normal conducting materials such as copper, aluminum, and alloys thereof. Examples of the element wire include a covered wire in which a metal conductor wire is covered with an insulating coating.

.. Superconducting conductor layer The superconducting conductor layer 12 includes a wire layer formed by spirally winding a plurality of superconducting wires around the outer periphery of the former 11. Examples of the superconducting wire include a tape-shaped wire such as an oxide-based silver sheathed wire containing bismuth such as Bi2223 and an oxide-based thin film wire containing a rare earth element such as RE123. The wire layer and the number of wires used can be selected according to a predetermined amount of power. The wire layer can be either a multilayer or a single layer. In the case of multiple layers, an interlayer insulating layer (not shown) in which insulating paper or the like is wound can be provided.

.. Electrical insulation layer The electrical insulation layer 13 is interposed between the superconducting conductor layer 12 and the ground layer 14 disposed outside thereof, and ensures electrical insulation between them. Examples of the electrical insulating layer 13 include a wound layer formed by spirally winding an insulating paper such as kraft paper or semi-synthetic paper including resin and kraft paper around the outer periphery of the superconducting conductor layer 12. Semi-synthetic paper includes polypropylene resin and kraft paper, such as PPLP (Polypropylene Laminated Paper) (registered trademark). A semiconductive layer (not shown) can be provided inside and outside the electrical insulating layer 13.

..Grounding layer The grounding layer 14 is provided on the outer periphery of the superconducting conductor layer 12 via the electric insulating layer 13 and is a conductive portion for taking a ground potential. Examples of the ground layer 14 include a winding layer formed by appropriately spirally winding the above-described superconducting wire, a wire made of a normal conducting material such as copper, a tape material, and a braided material. When the ground layer 14 is formed of a superconducting wire, the ground layer 14 can be used as a superconducting shield layer in AC power transmission.

An outer superconducting layer formed of a superconducting wire can be provided on the outer periphery of the electrical insulating layer 13, and a ground layer 14 formed of a normal conducting material can be provided separately. In this case, the outer superconducting layer can be used as a superconducting shield layer as described above. An interlayer insulating layer can be provided between the outer superconducting layer and the ground layer 14 of normal conducting material.

..Protective layer Here, the conventional cable core is mechanically protected by the ground layer 14 made of a conductive material such as a superconducting wire, and electrically between the ground layer 14 and the heat insulating tube 20 made of metal. For the purpose of insulation, a protective layer is provided on the outer periphery of the ground layer 14. For these purposes, in the conventional cable core, the protective layer is made of an electrically insulating material such as kraft paper. In the superconducting cable 1 of the first embodiment, when an accident such as a ground fault occurs in the superconducting cable 1 itself, the electrical insulating layer 13 breaks down and an arc is generated from the superconducting conductor layer 12 to the ground layer 14. One purpose of the protective layer 15 is to prevent this arc from reaching the heat insulating tube 20. Therefore, the superconducting cable 1 of Embodiment 1 includes an arc resistant layer in the protective layer 15.

・ ・ ・ Arc-resistant layer ・ ・ ・ ・ Material The arc-resistant layer prevents arc discharge from the superconducting conductor layer 12 through the grounding layer 14 to the heat insulating tube 20 (particularly the inner tube 21) in the event of a ground fault or the like as described above. What is necessary is just to have arc resistance, tracking resistance, heat resistance, thickness, or the like that can be interrupted. In particular, the constituent material of the arc resistant layer preferably includes a high arc resistant material having excellent arc resistance and tracking resistance. Here, the high arc-resistant material is an organic material such as a resin, a non-metallic inorganic material such as a carbon-based material, glass, or ceramic, or a fiber or metal made of a non-metallic material (organic material or inorganic material). . In addition, the constituent material of the arc resistant layer includes a material considered to be inferior in arc resistance compared to the above-mentioned high arc resistant material, specifically, an insulating material (craft paper, semi-synthetic paper, cotton, etc.) described later. be able to.

Among the high arc resistant materials, specific organic materials are polyethylene resin, polypropylene resin, fluorine resin represented by polytetrafluoroethylene resin, silicone resin, amino resin, aramid resin, polyphenylene sulfide (PPS) resin, polyimide Examples thereof include one or more resins selected from (PI) resins and polyacrylate resins, and rubbers such as silicone rubber. Specific examples of the amino resin include urea resin (urea resin), melamine resin, aniline resin, and guanamine resin. These resins are excellent in arc resistance and tracking resistance. For example, with respect to polyethylene resin, polypropylene resin, and polytetrafluoroethylene resin, Table 1 shows typical values of arc resistance (seconds) and tracking resistance when the following arc resistance test is performed.

In the arc resistance test, two tungsten electrodes are placed facing each other on a test piece made of an electrically insulating material such as an organic material among the non-metallic materials listed, and a high voltage and a small current are placed in this facing state. The time (seconds) until the sample surface is carbonized and the electrical insulation is lost is measured (see JIS K 6911 (1995), 5.15 arc resistance). Test conditions include, for example, a voltage of 12,500 V and a current of 10 mA or more and 40 mA or less. The test conditions can be adjusted according to the operating current of the superconducting cable 1 and the like. The longer the measured time (seconds), the better the arc resistance.

The tracking resistance can be evaluated by a tracking resistance test method for measuring arc deterioration. Specific test methods include the IEC method (International Electrotechnical Commission), the DIN method (Deutsches Institute for Normung), the Dust Fog method, the high-voltage microcurrent arc resistance test method, the Differential Wet method, and the Dip Track method.

Among the high arc resistant materials, as fibers made of non-metallic materials, for example, fibers made of resin (organic material) such as aramid fibers (organic fibers), fibers made of inorganic materials such as carbon fibers, glass fibers, ceramic fibers ( Inorganic fiber). In particular, high-performance and high-performance fibers having excellent mechanical properties such as strength and rigidity, and excellent heat resistance and flame retardancy can be mentioned. High-performance and high-performance fibers are called high-strength fibers with excellent strength, super fibers, etc., especially high-strength and high-modulus fibers with excellent strength and rigidity, especially high-heat-resistant fibers with excellent heat resistance and flame resistance Etc.

Examples of the high-strength fiber, high-strength / high-modulus fiber include para-aramid fiber, ultrahigh molecular weight polyethylene fiber, polyarylate fiber, polyparaphenylene benzobisoxal (PBO) fiber, and carbon fiber.
Examples of the high heat resistant fiber include meta-aramid fiber, PPS fiber, PI fiber, and fluorine fiber.
Examples of non-combustible fibers include glass fibers and ceramic fibers.
A typical example of the constituent material of the glass fiber is silica (SiO ₂ ). Examples of the ceramic constituting the ceramic fiber include metal oxides such as aluminum oxide (alumina), non-metal oxides such as boron oxide, and other metal carbides and metal nitrides. A fiber containing silica and ceramics, for example, a ceramic fiber containing silica and alumina, or a fiber containing a plurality of types of ceramics, for example, a ceramic fiber containing silica, boron oxide, and alumina can be used.
Glass fibers and ceramic fibers can form an arc resistant layer that is more excellent in arc resistance. Therefore, the total thickness of the arc resistant layer can be reduced. Aramid fibers can form an arc-resistant layer that is also excellent in strength. Therefore, it is preferable that the constituent material of the arc resistant layer includes at least one high arc resistant material of glass fiber, ceramic fiber, and aramid fiber. More preferably, at least one of a glass fiber and a ceramic fiber and an aramid fiber are included.

When the constituent material of the arc-resistant layer contains resin, resin fiber, or rubber, adding appropriate fillers or compounding agents to the resin or rubber will increase the arc resistance, strength, etc. compared to the resin or rubber alone. May have excellent mechanical properties. A filler and a compounding agent can be suitably selected according to a resin component or a rubber component, and examples thereof include the following inorganic materials. Examples of fillers for improving arc resistance with respect to silicone resins and silicone rubbers include alumina compounds such as alumina trihydrate. Silica (silicon oxide) can be used as a filler for improving the strength of silicone resin and silicone rubber. Examples of the compounding agent for the PPS resin and the PPS fiber include the following decomposition endothermic filler, and a carbonization inhibitor that promotes carbon dioxide and water when the polymer is completely burned. Examples of the constituent material of the decomposition endothermic filler include aluminum hydroxide, magnesium hydroxide, calcium borate, and zinc borate. A well-known thing can be utilized for a filler and a compounding agent.

Among the high arc resistant materials, specific metals include lead, iron-based metals including iron group elements such as stainless steel, nickel, and iron. The arc-resistant layer is expected to be usable not only with the above-mentioned electrically insulating materials such as organic materials but also with inorganic materials having conductivity such as metals.

Other constituent materials of the arc-resistant layer include composite materials in which different materials are combined, for example, fiber reinforced resin including the above-described resin and the above-described fiber.

.... Shape When the arc-resistant layer includes a wound layer in which a tape material (including a sheet material) composed of the organic material or inorganic material described above is wound, preferably the entire arc-resistant layer is substantially It is preferable that the winding layer is formed because an arc-resistant layer can be easily provided. An arc-resistant layer having a desired thickness can be easily formed by preparing a tape material having a desired thickness and width and winding the tape material around the outer periphery of the ground layer 14. Even an arc resistant layer having a multilayer structure can be easily formed. In particular, this winding layer preferably has a multi-layer structure of gap winding and at least one layer has a different winding direction, that is, an S winding layer and a Z winding layer. The winding direction may be changed for each layer (that is, S winding layers and Z winding layers are alternately present) or for each of a plurality of layers. A gap-wound multi-layer structure with both an S-winding layer and a Z-winding layer, and the Z-winding layer covers the gap of the S-winding layer. It can be set as the arc-proof layer which can suppress the fall of the interruption | blocking effect. And it is a multilayer structure of gap winding, Comprising: Even when it is a case where tape materials, such as the above-mentioned resin and metal, are provided by providing both S winding layer and Z winding layer, the channel of liquid refrigerant L Enough can be secured. Therefore, when the liquid refrigerant L is introduced into the heat insulating tube 20 of the superconducting cable 1 and the cable core 10 is impregnated with the liquid refrigerant L, the impregnation time can be shortened, and the superconducting cable 1 is excellent in manufacturability. The thickness and width of the tape material, the gap of the winding layer, the winding pitch, and the like can be selected as appropriate.

The above-mentioned fibers can be used in any form of woven fabric, braided material, and non-woven fabric. In any form, the arc can be sufficiently interrupted by making it dense. Even in the case of a dense fiber tape material, the flow path of the liquid refrigerant L can be sufficiently secured by providing a gap wound multilayer structure as described above and having both the S winding layer and the Z winding layer. On the other hand, depending on the degree of density, the flow path of the liquid refrigerant L can be secured while interrupting the arc by using a lap winding instead of a gap winding. What is necessary is just to set the density of a woven fabric, a nonwoven fabric, etc., the thickness of a tape material, the gap of a winding layer, etc. so that the interruption | blocking of an arc and ensuring of the flow path of the liquid refrigerant | coolant L may be compatible.

The arc-resistant layer has a multilayer structure in which wound layers of tape materials having different constituent materials or wound layers of tape materials having different forms (for example, resin tape and fiber tape, woven tape and non-woven tape) are combined. Can do. For example, two or more kinds of winding layers selected from a winding layer of the tape material made of the resin, a winding layer of the tape material made of the fiber, and a winding layer of the tape material made of the metal are provided in combination. A form is mentioned.

As a specific example of the arc-resistant layer having a multilayer structure composed of a plurality of different materials, the semi-synthetic paper layer formed from semi-synthetic paper such as the above-mentioned PPLP, and at least one of glass fiber and ceramic fiber in order from the inner peripheral side The form containing the inorganic fiber layer formed from an organic fiber layer formed from an aramid fiber is mentioned.
The semi-synthetic paper layer smoothes the surface of the grounding layer 14 composed of a metal tape material or a metal wire, presses the metal tape material or the like, prevents damage to the grounding layer 14 due to glass fiber, Functions as a base layer for the inorganic fiber layer. Moreover, since semi-synthetic paper such as PPLP has better arc resistance than insulating paper such as kraft paper, the total thickness of the arc-resistant layer is reduced, which contributes to a reduction in the diameter of the cable core 10.
When the inorganic fiber layer is composed of glass fiber, the glass fiber is excellent in flame retardancy, and thus contributes to the construction of an arc resistant layer excellent in arc resistance. When the inorganic fiber layer is composed of ceramic fibers, the ceramic fibers have better arc resistance than glass fibers, and thus contribute to the construction of an arc resistant layer that is more excellent in arc resistance. When the inorganic fiber layer includes both glass fiber and ceramic fiber, it can be an arc resistant layer that is more excellent in arc resistance.
The organic fiber layer can be further improved in arc resistance by being provided with the inorganic fiber layer, and it is also made of high strength and high elastic modulus fiber such as aramid resin, especially para-type aramid fiber. It is done.

In addition, the arc-resistant layer can include a wound layer in which an insulating tape material made of an insulating material such as an insulating paper such as kraft paper, a cloth such as cotton, or a semi-synthetic paper such as PPLP is wound. For example, the thickness of the wound layer of the insulating tape material may be 1 mm or more, more preferably 1.5 mm or more, more than 2.5 mm, 3 mm or more. Even when these insulating tape materials are used, if they are sufficiently thick as described above, they are expected to function sufficiently as an arc-resistant layer. In particular, if semi-synthetic paper such as PPLP is included, the arc resistance can be improved, so that it is expected that the thickness of the wound layer of the insulating tape material can be reduced as described above and contribute to the reduction of the diameter of the cable core 10. The The thicker the wound layer of the insulating tape material, the better the arc resistance. However, the bending characteristics of the core 10 may be deteriorated and the core 10 may be increased in diameter. In consideration of arc resistance, mechanical properties of the superconducting cable 1, size, and the like, it is considered preferable to include the above-described high arc-resistant material when the above-described insulating material is included. For example, the wound layer of the insulating tape material can be provided below the layer made of the above-mentioned high arc resistant material (on the grounding layer), or above or both above and below so as to be sandwiched between the top and bottom (the above-mentioned multilayer). See also specific examples of structures). When the arc-resistant layer includes a wound layer of a metal tape material, electrical insulation between the arc-resistant layer and the inner tube 21 of the heat insulating tube 20 is provided if the wound layer of the insulating tape material is provided on the outer periphery thereof. It is preferable because the properties are improved. When the winding layer of the insulating tape material is provided together with the layer made of the high arc-resistant material, the thickness of the winding layer of the insulating tape material is about 1 mm or less.

.... Thickness The thicker the arc resistant layer, the easier it is to interrupt the arc. Although it depends on the material of the arc-resistant layer, it is considered that 0.5 mm or more, more preferably 1 mm or more is preferable when using non-metallic materials such as resin or fibers among the above-mentioned high arc-resistant materials. When using the above-mentioned metal, it is considered that 1 mm or more, and further 2 mm or more is preferable. If the arc-resistant layer is too thick, the cable core 10 and the superconducting cable 1 will be increased in size and diameter. Therefore, the thickness of the arc-resistant layer (total thickness in the case of a multilayer structure) is 16 mm or less, and further 10 mm or less. , 8 mm or less, 7 mm or less. If the arc-resistant layer has a thickness of about 5 mm or less, the core 10 and the cable 1 can be easily formed with a small diameter.

In the form of a multilayer structure including the semisynthetic paper layer, the inorganic fiber layer, and the organic fiber layer, the thickness of the semisynthetic paper layer is about 0.2 mm or more and 1 mm or less, and the thickness of the inorganic fiber layer is 1 mm. The thickness of the organic fiber layer is about 0.5 mm or more and about 5 mm or less, preferably about 2 mm or less.

..... Occupation ratio in protective layer The entire protective layer 15 can be an arc resistant layer. That is, the protective layer 15 can be formed of a tape material, an insulating tape material, or the like made of the above-described high arc resistant material such as an organic material or an inorganic material. The higher the occupation ratio of the layer made of the above-mentioned high arc resistant material, the better. The occupation ratio of the layer made of the high arc resistant material in the protective layer 15 is 80% or more, more preferably 85% or more, 90% or more in terms of thickness. Is preferred.

.... Other functions At least a part of the arc-resistant layer is provided with a fiber having excellent mechanical properties such as strength, particularly a high-strength layer composed of the above-described high-strength fiber and the above-described high-strength / high-modulus fiber In addition, the arc-resistant layer can be used as a tension member. The cable core 10 of this form can be provided with an arc resistant layer that is also used as a tension member.

As the fibers constituting the high-strength layer, the above-described high-strength fibers and high-strength / high-modulus fibers having a tensile strength of 1 GPa or more can be suitably used. By having such a strength, when manufacturing the superconducting cable 1, the high-strength layer can be suitably used as a pulling tension member when the cable core 10 is pulled into the heat insulating tube 20. The higher the tensile strength of the fibers constituting the high-strength layer, the better, and 1.5 GPa or more, and further 2 GPa or more can be mentioned. As the constituent material of the high-strength layer, non-metallic fibers called super fibers can be suitably used. When the entire arc-resistant layer or the arc-resistant layer is mainly composed of high-strength fibers or high-strength / high-modulus fibers, and the arc-proof layer is substantially the entire high-strength layer, arc resistance In addition, the strength against the tension at the time of pulling in can be sufficiently obtained. In the case where the high-strength layer is provided only in a part of the arc-resistant layer, for example, the other part can be composed of a material that is superior in arc resistance (multi-layer structure including the above-described inorganic fiber layer and organic fiber layer) Refer to the form).

When the high-strength layer is a fiber tape material as described above, and the wound layer is formed by winding this tape material, the winding pitch is preferably relatively long. Specific winding pitch is, for example, 400 mm or more and 2000 mm or less, preferably 600 mm or more and 1000 mm or less. By using such a relatively long pitch, the high-strength layer (winding layer) is tightened by pulling the high-strength layer at the time of pulling, and the cable core 10 is tightened, and an excessive force is applied to the core 10 by this tightening. Can be prevented. In addition, when the winding pitch satisfies the above range, it can have sufficient strength to withstand the tension at the time of pulling in compared with the case where it is vertically attached.

-Heat insulation pipe The heat insulation pipe 20 is a double structure pipe having an inner pipe 21 and an outer pipe 22 provided on the outer periphery of the inner pipe 21, and the space between the inner pipe 21 and the outer pipe 22 is evacuated. This is a vacuum heat insulating tube in which a vacuum heat insulating layer is formed in this space. The inner space of the inner tube 21 is a storage space for the cable core 10 and is filled with a liquid refrigerant L for maintaining the superconducting state of the superconducting conductor layer 12 and the outer superconducting layer (the refrigerant flow path). It is. The inner tube 21 and the outer tube 22 are metal tubes made of stainless steel or the like, and are excellent in flexibility when a corrugated tube or bellows tube, and have a small surface area and excellent heat insulating properties when used as a flat tube, and the pressure of the liquid refrigerant L Loss can be reduced. When a heat insulating material (not shown) such as a super insulation is provided between the inner tube 21 and the outer tube 22, it has higher heat insulating properties.

The outer side of the outer tube 22 of the heat insulating tube 20 is provided with an anticorrosion layer 24 made of an anticorrosion material such as vinyl or polyethylene.

-Manufacturing method The superconducting cable 1 of Embodiment 1 can be manufactured typically by accommodating the cable core 10 produced in the factory etc. in the heat insulation pipe | tube 20. As shown in FIG. By forming the heat insulation pipe 20 on the outer periphery of the core 10 or drawing the core 10 into the heat insulation pipe 20 separately manufactured, the core 10 can be stored in the heat insulation pipe 20. In addition, the superconducting cable 1 can also be manufactured by transporting the core 10 manufactured in a factory or the like to the laying site, laying the heat insulating pipe 20 in the laying path, and then storing the core 10 in the heat insulating pipe 20. When the arc-resistant layer includes the above-described high-strength layer, the high-strength layer is used as a tension member when the core 10 is pulled in and stored in the heat insulating tube 20 at a factory or a laying site. Members can be omitted. In this case, since the number of parts can be reduced, the superconducting cable 1 is excellent in manufacturability and installation workability.

-Effect Since superconducting cable 1 of Embodiment 1 is equipped with the arc-proof layer in which all the cable cores 10 accommodated in the heat insulation pipe | tube 20 contain specific high arc-proof material, accidents, such as a ground fault, are carried out to itself. Even when an arc is generated from the superconducting conductor layer 12 toward the ground layer 14, the arc does not reach the heat insulating tube 20 (inner tube 21). That is, the superconducting cable 1 can cut off the arc from the superconducting conductor layer 12 through the ground layer 14 to the heat insulating tube 20 by the arc-resistant layer. Therefore, the superconducting cable 1 can prevent damage to the heat insulating tube 20 at the time of an accident such as a ground fault.

In particular, the superconducting cable 1 of the first embodiment is a multi-core collective cable (three-core collective cable in this example), and one core 10 housed in the heat insulating tube 20 breaks down and is connected from the superconducting conductor layer 12. When an arc is generated in the formation 14, an arc directed to another core 10 adjacent to the core 10 can be interrupted by the arc-resistant layer. Therefore, the superconducting cable 1 can also prevent a short circuit from occurring between the adjacent cores 10 and 10 at the time of an accident such as a ground fault. That is, it is possible to prevent a transition from a ground fault accident to a short-circuit accident.

[Embodiment 2]
In the first embodiment, the multi-core collective cable in which the plurality of cable cores 10 are accommodated in one heat insulating tube 20 has been described. In addition, it can be set as the single core cable by which only one cable core 10 was accommodated in the one heat insulation pipe | tube 20. FIG.

In the superconducting cable (single-core cable) of the second embodiment, since the cable core 10 accommodated in the heat insulating tube 20 includes an arc resistant layer including a specific high arc resistant material, an accident such as a ground fault occurs in the superconducting cable. Even when an arc is generated from the conductor layer 12 toward the ground layer 14, this arc can be interrupted by the arc-resistant layer. Therefore, similarly to the superconducting cable 1 of the first embodiment, the superconducting cable of the second embodiment can prevent the heat insulating tube 20 from being damaged at the time of an accident such as a ground fault.

[Test Example 1]
A cable core for a superconducting cable having a multi-layer arc-proof layer on the outer periphery of the grounding layer was fabricated and the arc-proof characteristics were examined.
In this test, a superconducting conductor layer (using the above-described superconducting wire), an electrical insulating layer, an outer superconducting layer (using the above-mentioned superconducting wire) serving as a ground layer, and an outer periphery of the outer superconducting layer, in order from the inner periphery side, PPLP tape material winding layer (thickness 0.6 mm), glass fiber tape material winding layer (thickness 5 mm, silica cloth), aramid fiber tape material winding layer (thickness 1 mm, Kevlar ( A cable core (No. 1) provided with an arc-resistant layer provided with (registered trademark) cloth) was prepared. Each tape material is a commercial product.
As a comparison, a cable core (No. 100) not provided with the arc-resistant layer described above on the outer periphery of the outer superconducting layer was prepared. Sample No. The cable core No. 100 does not have an arc-resistant layer, except for sample No. Same as 1.

Prepared sample No. 1 cable core, sample no. 100 cable cores were inserted into the heat insulation tubes, respectively, and sample Nos. 1 superconducting cable, sample no. 100 superconducting cables are used, liquid nitrogen is introduced into the heat insulating tube of each sample, and the cable core of each sample is cooled by liquid nitrogen. In this state, an earth current is passed between the superconducting conductor layer and the outer superconducting layer of each sample to generate an arc between both layers.

As a result, Sample No. provided with a cable core that does not have an arc-resistant layer. In the 100 superconducting cable, the generated arc reached the heat insulating tube and the heat insulating tube was perforated, whereas the sample No. 1 having a cable core having an arc-resistant layer was formed. It was confirmed that the superconducting cable No. 1 was excellent in arc resistance because no hole was opened in the heat insulating tube. In this test, glass fiber was used as the constituent material of the inorganic fiber layer, but if it is ceramic fiber, it is superior in arc resistance characteristics, so the thickness of the wound layer can be reduced, or the insulation tube at the time of ground fault It is expected to increase the reliability of damage prevention.

The present invention is not limited to these exemplifications, but is defined by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

The superconducting cable of the present invention can be used for a DC transmission line and an AC transmission line. The cable core for a superconducting cable of the present invention can be used as a constituent member of a superconducting cable.

DESCRIPTION OF SYMBOLS 1 Superconducting cable 10 Cable core for superconducting cable 11 Former 12 Superconducting conductor layer 13 Electrical insulation layer 14 Ground layer 15 Protective layer (arc-proof layer)
20 Heat insulation pipe 21 Inner pipe 22 Outer pipe 24 Anticorrosion layer L Liquid refrigerant

Claims (6)

1. A superconducting conductor layer;
   A grounding layer provided on the outer periphery of the superconducting conductor layer via an electrical insulating layer;
   A protective layer provided on the outer periphery of the grounding layer,
   The protective layer is made of high performance / high performance fiber, polypropylene resin, polyethylene resin, polytetrafluoroethylene resin, silicone resin, amino resin, aramid resin, polyphenylene sulfide resin, polyimide resin, polyacrylate resin, silicone rubber and metal. A cable core for a superconducting cable including an arc-resistant layer composed of one or more selected materials.
2. The cable core for a superconducting cable according to claim 1, wherein the arc-resistant layer includes a wound layer in which a tape material made of the material is wound.
3. The arc resistant layer is a multilayer structure composed of a plurality of different materials,
   In order from the inner peripheral side, a semi-synthetic paper layer formed from semi-synthetic paper containing polypropylene resin and kraft paper, an inorganic fiber layer formed from at least one of glass fiber and ceramic fiber, and aramid fiber are formed. The cable core for a superconducting cable according to claim 1 or 2, comprising an organic fiber layer.
4. The superconducting device according to any one of claims 1 to 3, wherein the arc-resistant layer includes a high-strength layer composed of fibers having a tensile strength of 1 GPa or more among the high-performance and high-function fibers. Cable core for cable.
5. A cable core for a superconducting cable according to any one of claims 1 to 4,
   A superconducting cable comprising a heat insulating tube for housing the cable core for the superconducting cable.
6. The superconducting cable according to claim 5, wherein the heat insulating pipe includes a plurality of cable cores for the superconducting cable.

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