JPS63276209A - Stationary induction electric apparatus - Google Patents

Abstract

PURPOSE:To shield the magnetic flux of the title electric apparatus almost completely without incurring a loss on a shielding plate by a method wherein a magnetic shielding plate is composed of a metallic oxide superconductive material, and the outside of a container is cooled by the refrigerant with which the critical temperature of the superconductive material can be maintained. CONSTITUTION:The winding 2 wound around an iron core 3 is arranged in a tank 1, and a liquid 4 to be used to cool and electrically insulate the contents of the tank 1 is filled in the tank. A magnetic shielding plate 5 of supercondu ctive material consisting of a metal oxide is attached to the inner wall, the side plate and a part of the cover of the tank 1, and the outside of the tank is surrounded by the container 7 wherein the refrigerant 6, with which the critical temperature of the superconductive material can be maintained is filled. Even when the leakage magnetic flux is to be infiltrated into the tank wall from the winding and the like of the transformer, it can be repelled almost completely by the action of the magnetic shielding plate 5 consisting of the superconductive material.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to stationary induction electric appliances such as transformers and accelerators.
In particular, the present invention relates to a stationary induction electric appliance equipped with a low-loss magnetic shielding device with excellent magnetic shielding effect.

[Conventional technology]

In conventional stationary induction electric appliances such as transformers, a conductive magnetic shield device is installed inside the tank wall to prevent leakage magnetic flux from the windings from penetrating the tank wall. This uses the effect of a repulsive magnetic field caused by the eddy current flowing through the shield plate to prevent leakage magnetic flux from penetrating the tank wall. To maximize this effect, copper or aluminum plates with low electrical resistance are usually used. It is being Incidentally, a magnetic shielding device for a transformer is described in Japanese Utility Model Application Publication No. 118224/1983.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, the eddy current value is limited by the electrical resistance of a single plate or aluminum plate, so there is a limit to the effect of the repulsive magnetic field of the magnetic shield, and the shield plate due to this eddy current The occurrence of losses was also a problem.

An object of the present invention is to provide a highly efficient stationary induction electric appliance that completely achieves the effect of the repulsive magnetic field of a magnetic shield and almost eliminates loss generated in the shield plate.

[Means for solving problems]

The above object is achieved by attaching a magnetic shield to the inner wall of the tank using a metal oxide superconductor having a high critical temperature.

[Effect]

A magnetic shield plate made of metal oxide superconductor is
It has the characteristics of complete diamagnetism and zero electrical resistance that superconductors basically have. Therefore, by attaching this magnetic shield to the inner wall of the tank, it is possible to almost completely shield the magnetic flux without causing any loss in the shield plate.

〔Example〕 Hereinafter, the present invention will be specifically explained using the drawings.

FIG. 1 is a vertical sectional view of the main parts of the transformer according to the present invention, in which a winding 2 wound around an iron core 3 is arranged in a tank 1, and a liquid is used to cool and electrically insulate the contents. 4 is filled in the tank. On the inner wall of the tank 1, a magnetic shield plate 5 made of a superconductor made of metal oxide is attached to the side plate and part of the cover of the tank, and the outside of the tank is a container filled with a refrigerant 6 capable of maintaining the critical temperature of superconductivity. It has a structure surrounded by 7. Note that, for example, a metal oxide material having a perovskite crystal structure is used as the magnetic shield of this superconductor, and liquid nitrogen, which is inexpensive and easy to handle, is suitable as the coolant.

The area around the container 7 filled with the refrigerant 6 is insulated with a material such as a foam material, but the heat insulating material 8a that insulates the magnetic shield plate 5 inside the tank 1 is the container 7 filled with the refrigerant 6.
The heat insulating effect is weaker than that of the heat insulating material 8b attached to the outside of the transformer, and the heat from the liquid 4 that cools the contents of the transformer can also be removed.

As described above, in the configuration of the present invention, even if leakage magnetic flux from the transformer windings tries to enter the tank wall, the magnetic flux is almost completely removed by the action of the magnetic shield plate made of superconductor attached to the front surface. Since the magnetic flux is repelled, the problems caused by magnetic flux penetrating the tank wall and causing loss can be virtually eliminated. Further, even if an excessive eddy current flows through the magnetic shield plate 5 to repel magnetic flux, since it is a superconductor, no loss occurs at all, and an extremely efficient magnetic shield plate can be provided.

Furthermore, since the structure is such that the liquid 4 inside the transformer can be cooled by the refrigerant 6 that cools the magnetic shield plate of the superconductor, it has conventionally been used to cool liquids such as mineral oil. It also has the effect of almost eliminating the need for many cooling devices such as radiators and fans.

Fig. 2 shows another embodiment, but it shows the same parts as the embodiment shown in Fig. 1, in which a non-condensable gas is used to cool and electrically insulate the windings 2 and iron core 3 inside the transformer. 9. For example, SF
This is the case when e-gas or the like is used. The effect of the magnetic shield plate 5 made of a metal oxide superconductor attached to the inner wall of the tank 1 is exactly the same as that of the embodiment shown in FIG. By keeping it at a sufficiently low temperature, its effectiveness can be improved to that of a liquid.

FIG. 3 shows another example of a liquid and gas mixture type in which the windings 2, core 3, etc. of a transformer are placed in a tank 10 filled with cooling liquid 4, and the outside is filled with gas 9. Even in such a case, exactly the same effect can be achieved by using the same structure of the magnetic shield plate 5 as in FIGS. 1 and 2 described above.

In the previous examples, we have described an example in which a metal oxide-based superconducting material with a perovskite crystal structure is used as a magnetic shield plate, and the critical temperature of superconductivity is maintained using liquid nitrogen. If this material is applied to the magnetic shield plate, refrigerants such as liquid nitrogen and associated heat insulating materials are almost unnecessary or significantly simplified, further promoting the miniaturization and weight reduction of equipment.

〔Effect of the invention〕

According to the stationary induction electric appliance of the present invention as described above, not only can the magnetic flux shielding effect by the magnetic shield plate be almost completely ensured, but also the loss generated in the shield plate can be reduced to almost zero, resulting in extremely low loss. It is possible to provide a static induction appliance with low efficiency and high efficiency. In addition, by cooling the magnetic shield plate made of superconductor and cooling the contents of the stationary induction electric device, it is possible to significantly reduce the amount of equipment required to cool the contents conventionally.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a transformer showing an embodiment of the present invention;
FIGS. 2 and 3 are sectional views of main parts of a transformer showing other embodiments of the present invention. 1...tank, 2...winding, 3...iron core, 4...
・Liquid, 5...Magnetic shield plate, 6...Refrigerant, 7...
- Container, 8a. \ζ Festival 10 Z exit

Claims (1)

[Claims] 1. In a stationary induction electric appliance in which a magnetic shield plate is attached to the inner wall of a container and a main body is housed in the container, the magnetic shield plate is composed of a metal oxide-based superconductor, and A stationary induction electric appliance, characterized in that the outside of the container is cooled with a refrigerant that can maintain the critical temperature of superconductivity. 2. The stationary induction electric appliance according to claim 1, wherein a liquid or gas having excellent electrical insulation properties is used as the material filling the inside of the container. 3. The stationary induction electric appliance according to claim 1, wherein a compound that exhibits a superconducting phenomenon at ambient temperature is used as the metal oxide-based superconductor.