JPH01190217A - Superconducting current limiter - Google Patents

Abstract

PURPOSE:To obtain an economic superconducting current limiter having high cooling efficiency and reliability, by forming a basic member for winding superconductor in non-inductive coil into cylindrical shape and providing many grooves in the outer circumference thereof. CONSTITUTION:A superconductive current limiter comprises a cylindrical basic member 4 having many grooves 3 in the outer circumference thereof for winding a high temperature oxide superconductor (superconducting wire) 2 having a critical temperature higher than the boiling temperature of liquid nitrogen in the shape of non-inductive coil. The grooves 3 made in the cylindrical basic member 4 provide refrigerant 5 such as liquid nitrogen for cooling the superconducting wire 2 with wider contact area. Consequently, cooling efficiency is improved under normal state, and the temperature lowers easily even upon temperature rise after quenching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a superconducting current limiting device using an oxide high temperature superconducting material.

(Conventional technology) The application of superconductors to power equipment has been studied for a relatively long time, and recently, along with the development of AC superconducting wires, research into the application of superconductors to AC electrical equipment such as transformers has also begun. It's progressing. However, there are various technical problems in putting it into practical use.

This is due to the fact that conventional equipment using superconducting materials such as NbTi, Nb, and Sn, which are premised on cooling with liquid helium, requires the extreme technology of freezing at extremely low temperatures, which is a problem in terms of economy and reliability. One of the major factors is that this has been a hindrance to practical application.

However, recently, the development of oxide-based high-temperature superconductors has progressed rapidly, and 'tRa, Cu, 0. The discovery of materials such as -1 that exhibit the characteristics of superconductors, such as zero electrical resistance and complete diamagnetism above the temperature of liquid nitrogen, has been reported in various places.

When such high-temperature superconducting materials are used, liquid nitrogen etc. can be used as a refrigerant, which not only reduces the cost of the refrigerant itself, but also makes refrigeration technology much easier, making it not only economical but also highly reliable.・As the equipment becomes available, it is expected that its application to power equipment will progress rapidly.

In particular, current limiting devices using high-temperature superconductors are being developed in many fields because they can be applied to take advantage of the characteristics of high-temperature superconductors.

However, current limiting devices using such high-temperature superconductors have the following problems.

(Issue to be solved by the invention) Current limiting devices using high-temperature superconductors that have been considered in the past, for example, can be A rectangular plate is used because it has a cross-sectional area corresponding to the current that needs to be passed through it, a length necessary as a high-resistance material after quenching, and a non-inductive configuration so that the critical magnetic field does not reach the steady state. The conductor plates 1 were stacked in which the oxide superconductors 1a were arranged in a zigzag pattern on the base material 1b. In such a configuration, problems such as poor cooling efficiency of the superconductor have occurred. Furthermore, the overall space factor is not good, and it is not economical to incorporate such a large device into a conventional switchgear.

The present invention improves the drawbacks of such superconducting current limiting devices,
The objective is to obtain a highly reliable and economical superconducting current limiting device with good cooling efficiency.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, in the present invention, a base material for winding a superconductor into a non-inductive coil shape is made into a cylindrical shape. Furthermore, a large number of grooves are provided on the outer periphery.

(Function) When configured as described above, the area in contact with a refrigerant such as liquid nitrogen increases, resulting in improved cooling efficiency during steady use and after quenching.

(Example) An example of the present invention is shown in FIG. A cylindrical base material 4 with a large number of grooves 3 on its outer periphery is used as a base material on which an oxide high-temperature superconductor (superconducting wire) 2 having a critical temperature higher than the boiling point of liquid nitrogen is wound into a non-inductive coil shape. . The grooves 3 provided in the cylindrical base material 4 increase the contact area with a coolant 5 such as liquid nitrogen used for cooling the superconducting wire 2 . By increasing the cooling area of the refrigerant 5, the cooling efficiency in a steady state is improved, and even if the temperature rises after quenching, the temperature tends to drop because the cooling area is large.

In addition to the superconducting current limiting device having the above configuration, a superconducting current limiting device as shown in FIG. 2 can be considered. A plurality of cylindrical insulator supports 6 are used as a base material on which the superconducting wire 2 is wound in a non-inductive coil form, for example, in an airtonbury manner.

By adopting this method, the contact area between the superconducting wire 2 and the refrigerant 5 is increased, and the cooling efficiency during steady state and after quenching is improved.

Further, FIGS. 4(a) and 4(b) are views showing another embodiment of the present invention, in which an oxide superconductor having a critical temperature higher than the boiling point of liquid nitrogen is formed on the outer peripheral surface and the inner peripheral surface of a cylindrical insulator 42. A superconducting wire 2 made of a material is wound into a coil to form an outer coil 43 and an inner coil 44. The outer coil 43 and the inner coil 44 are wound at a turns ratio such that the strength of the magnetic field inside the coil is equal, and the winding method is such that the directions of the magnetic fields of the outer coil 43 and the inner coil 44 are opposite to each other. It is wound so that it is in the erasing direction.

With such a configuration, a superconducting coil that hardly generates electromagnetic induction inside the coil can be obtained.

Furthermore, the present invention may be configured as shown in FIGS. 5(a) and 5(b), that is, a superconducting current limiting unit 51 made of an oxide high temperature superconductor having a critical temperature equal to or higher than the boiling point of liquid nitrogen has a cylindrical base material. 52, a superconducting wire 51a is arranged in a coil shape.

The superconducting current-limiting unit 51 is configured coaxially, and the way of winding the inner unit 52a and the middle unit 52b in FIG. 5(b) is devised so that no induction occurs. For example, in Figure 5 (
By reversing the winding of the inner unit 2a and the middle unit 2b in b) to create a non-inductive state, the magnetic field is reduced and a decrease in critical current can be prevented. Moreover, since it has a cylindrical structure, it is possible to provide a current limiting device with high insulation performance.

In addition, as shown in FIG. 6(a), a superconducting current limiting unit 51
A superconducting wire 51a is arranged in a non-inductive coil shape on a cylindrical base material 52.

The above-mentioned superconducting current limiting unit 501.1 constitutes a superconducting coil. The non-inductive state is created by winding the superconductors 51a in opposite directions on the cylindrical base material 52 so that their magnetic fluxes cancel each other out.

Furthermore, the superconducting current limiting unit 51 can be used under high voltage by having a multiple coaxial configuration as shown in FIG. 6(b).

Further, in FIG. 7, a superconducting current-limiting unit 51 made of an oxide high-temperature superconductor having a critical temperature higher than the boiling point of liquid nitrogen is arranged in a zigzag pattern on a plate-shaped base material 53 so that the superconducting wire 51a is in a non-inductive state. has been done. The plate-like base material 53 is made of a semiconductor (for example, carbon), and the ends thereof are rounded to prevent an increase in electric field during quenching. Since the plate-like base material 53 is a semiconductor, it is possible to provide a superconducting current limiting device with high insulation performance that can prevent an increase in the electric field and a decrease in dielectric strength in the A section and the B section.

In the embodiment shown in FIGS. 8(a) and 8(b), superconducting wires 81a are arranged in a zigzag manner on both sides of a rectangular plate-shaped base material 81b of a superconducting current limiting unit 81 so as to be in a non-inductive state. superconductor 8
1a, the construction method is reversed on both sides of the square plate-shaped base material 81b, and a non-inductive state is formed.

In order to achieve high voltage, the superconducting current limiting unit 81 has the following features:
Since it is configured in a polygonal shape, it is possible to provide a superconducting current limiting device with high insulation performance.

〔Effect of the invention〕

As explained above, according to the present invention, in a superconducting current limiting device using an oxide superconductor having a critical temperature higher than the boiling point of liquid nitrogen, a groove is formed on the outer periphery of the base material around which the superconductor is wound in a non-inductive coil shape. The cooling efficiency can be improved by providing a support member or using a plurality of insulator supports as the base material, the overall space factor is improved, and it is economical.

In addition, coils are formed on the outer and inner surfaces of the cylindrical insulator,
Since it has a non-inductive effect, it has no inductive effect.
In addition, it is possible to provide a superconducting coil with a high cooling effect due to its cylindrical shape.

In addition, superconductors are arranged in a coil shape on a cylindrical base material,
By configuring coaxially multiple units configured in the form of non-inductive coils, it is possible to prevent a drop in critical current and obtain a superconducting current limiting device with high insulation performance under high voltage. By making the material a semiconductor and further rounding the ends, a superconducting current limiting device with high insulation performance even in a high voltage state can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, FIG. 2 is a perspective view showing another embodiment, FIGS. 3(a) and 3(b) are block diagrams of a conventional superconducting current limiting device, and FIG. 4 to 8 are block diagrams showing other embodiments of the present invention. 1... Superconducting current limiting device 2... Superconducting wire 3...
Groove 4 provided on the outer periphery of the cylindrical base material...Cylindrical base material
5... Refrigerant 6... Insulator support agent Patent attorney Rule Ken Chika Yudo Ken Daishimaru Figure 1 Figure 2 (α) Figure 3 (α) (b) Figure 4 (α) Figure 5 (α) (b) Figure 6 Figure 7

Claims (1)

[Claims] A superconducting wire characterized by winding a superconducting wire made of an oxide superconductor having a critical temperature higher than the boiling point of liquid nitrogen into a non-inductive coil shape on a cylindrical base material with many grooves on its outer periphery. flow device.