JPH01122111A - Superconducting transfer - Google Patents

Abstract

PURPOSE:To prevent a transformer tank from exploding and to enhance the cooling efficiency of a superconducting transformer by incorporating the tank partly having a pressure avoiding film in a vacuum vessel. CONSTITUTION:A transformer body 1 disposed in a transformer tank 2 employs as its winding an oxide superconducting material, and its winding is operated in a cryogenic state in which the winding can be operated in a superconducting state, such as in a state in which it is dipped in liquid nitrogen. A pressure avoiding film 4 is partly provided in the tank 2, the tank 2 is contained in a vacuum vessel 3, and the vessel 3 is evacuated in vacuum. Accordingly, the liquid nitrogen is evaporated by the local heat of the winding, the pressure in the tank 2 is raised, but the film 4 provided partly in the tank 2 is broken by a predetermined pressure, and the evaporated gas is discharged into the vessel 3. Thus, it can prevent the tank 2 from exploding due to the evaporation of refrigerant, such as the liquid nitrogen, thereby enhancing its cooling efficiency.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a superconducting transformer using a superconducting conductor.

(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 because conventional devices using superconducting materials such as NbTi, Nb, and Sn, which are designed to be cooled by liquid helium, require the ultimate technology of freezing at extremely low temperatures.
One of the major factors was that economic efficiency and reliability were obstacles to practical application.

However, recently, the development of oxide-based high-temperature superconducting materials has progressed rapidly, and materials such as YBa, Cu, O, -1, etc., which exhibit characteristics as superconductors such as zero electrical resistance and complete diamagnetic properties above liquid nitrogen temperature, have been discovered in various places. It has been reported in

When such high-temperature superconducting materials are used, liquid nitrogen 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 equipment. As a result, it is expected that its application to power equipment will advance rapidly.

When superconducting conductors are applied to transformers, very efficient transformers can be obtained, especially since winding losses are eliminated. However, superconducting transformers using superconducting conductors have the following problems.

(Problem that the invention attempts to solve) The current density in the transformer winding is eddy current.

May be uneven. The transformer windings are locally quenched due to the non-uniform current density within the windings, which causes the windings to locally increase in temperature, but are quickly cooled down by a refrigerant such as liquid nitrogen. This rapid cooling of the windings causes the liquid nitrogen to vaporize, increasing the pressure inside the transformer tank and potentially causing an explosion. Furthermore, since the tank storing the refrigerant such as liquid nitrogen is exposed to the atmosphere, the cooling efficiency is poor, and the liquid nitrogen gradually vaporizes, causing the pressure inside the tank to rise. This may cause the transformer tank to explode.

The present invention has been made to solve these problems, and aims to prevent explosions in transformer tanks due to vaporization of refrigerants such as liquid nitrogen, and to obtain superconducting transformers with high cooling efficiency. shall be.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, one aspect of the present invention is to provide a pressure relief membrane on the outer wall of the transformer tank, and to house the transformer tank in a vacuum container.

Prevent transformer tank explosion and improve cooling efficiency.

(Function) In a superconducting transformer having such a configuration, liquid nitrogen is vaporized due to a temperature rise due to local quenching of the windings. When the pressure inside the transformer tank increases due to the vaporization of liquid nitrogen, the pressure relief membrane installed on the outer wall of the transformer tank ruptures.
The vaporized gas is released into a vacuum container to prevent explosion of the transformer tank. Furthermore, since the first normal transformer tank is surrounded by a vacuum container, a superconducting transformer with good cooling efficiency can be obtained.

(Example) Embodiments of the present invention will be described below based on the drawings.

In the figure, a transformer main body 1 placed inside a transformer tank 2
uses an oxide-based superconducting material for its windings, and operates at low temperatures where one winding can operate in a superconducting state.

For example, it is operated while immersed in liquid nitrogen.

A pressure relief membrane 4 is provided in a part of the transformer tank 2, the transformer tank 2 is housed inside the vacuum container 3, and the inside of the vacuum container 3 is in a vacuum state.

With this configuration, the following first-order actions and effects are produced. The current density in the windings of the transformer body 1 becomes non-uniform due to eddy currents, causing local quenching.This quenching causes a local temperature rise in the windings, but the quenching causes a local temperature rise in the windings. Fluid nitrogen is vaporized by the heat generated by the 0 winding, which is rapidly cooled by the transformer tank 2, and the pressure inside the transformer tank 2 rises. The vaporized gas is released into the vacuum container 3. This prevents the transformer tank 2 from exploding due to vaporization of the refrigerant.

In addition, since the refrigerant is housed in the vacuum container 3 which is normally in a vacuum state, cooling efficiency is improved and vaporization of the refrigerant is reduced.

The pressure rise inside the tank 2 is also reduced.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent explosion of the transformer tank due to pressure increase due to vaporization of the refrigerant, and to obtain a superconducting transformer with improved cooling efficiency.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention. 1...Transformer body 2...Transformer tank 3.
...Vacuum container 4...Pressure membrane agent Patent attorney Noriyuki Chika Ken Yudo Daishimaru Ken

Claims (1)

[Claims] A superconducting transformer using an oxide-based superconducting material for the windings, in which a pressure relief membrane is provided in a part of the transformer tank, and the transformer tank is housed in a vacuum container.