JPH0738347B2 - Gas insulated electromagnetic induction equipment - Google Patents

Description

The present invention relates to a gas-insulated electromagnetic induction device, and more particularly,
The present invention relates to a gas-insulated electromagnetic induction device that cools and insulates a main body of an electromagnetic induction device housed in a vessel filled with an insulating liquid refrigerant and a non-condensable insulating gas.

[Conventional technology]

Conventionally, an electromagnetic induction device a high voltage such as a gas insulated transformer, at a large capacity, SF is used as insulating medium ₆
Insulating liquid refrigerant is used as the cooling medium because the gas alone cannot sufficiently cool the gas.

The dissolution characteristics of SF ₆ gas in this liquid refrigerant show the tendency shown in FIG. 3, and as the temperature decreases, more SF ₆ gas dissolves in the liquid refrigerant, and the gas molecule density in the equipment tank decreases. As for the relationship between SF ₆ gas molecular density and dielectric strength, it is known that the dielectric strength decreases as the gas molecular density decreases, as shown in FIG.

Therefore, conventionally, the insulation design is performed according to the dielectric strength determined by the gas molecule density when the temperature of the refrigerant is the lowest.

[Problems to be solved by the invention]

In the conventional gas-insulated electromagnetic induction equipment as described above, the insulation resistance is higher than necessary during normal operation with a high refrigerant temperature, but insulation is performed according to the case where the insulation strength is the lowest. Since it is designed, there is a problem that the insulation size becomes large, and thus the device becomes large.

The present invention has been made to solve such a problem, and improves the dielectric strength when the refrigerant temperature is low, approaches the dielectric strength when the refrigerant temperature is high during operation, and thus downsizes the device. An object is to obtain a gas-insulated electromagnetic induction device that can be used.

[Means for solving problems]

A gas-insulated electromagnetic induction device according to the present invention, a refrigerant container for collecting a liquid refrigerant, a refrigerant supply / discharge device for discharging the liquid refrigerant from the device tank to the refrigerant container, and supplying the liquid refrigerant from the refrigerant container to the device tank. , A gas return device for returning gas from the refrigerant container to the equipment tank.

[Action]

In the present invention, the heating element in the equipment tank during operation,
For example, a liquid refrigerant for cooling the main body of the electromagnetic induction device is required, but when the operation is stopped, there is no heating element in the device tank, and the liquid refrigerant for cooling is unnecessary. Then, if the temperature inside the equipment tank decreases, a large amount of SF ₆ gas will dissolve in the liquid refrigerant, so in order to prevent the dissolution, the liquid refrigerant will be moved to the outside of the equipment tank while the operation is stopped.

As a result, even if the temperature in the equipment tank drops,
The gas molecule density in the equipment tank is not reduced, and the dielectric strength can be maintained at a value close to that when the refrigerant temperature is high.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which a liquid-cooled gas-insulated electromagnetic induction device is taken as an example. In the figure, the liquid refrigerant (1) is sent to the heat exchanger (3) by the liquid sending pump (2) and then cools the electromagnetic induction device body (5) as droplets (4).

In this embodiment, a refrigerant container (7), a refrigerant supply / discharge device (8) and a gas returning device (9) are provided outside the equipment tank (6) for refrigerant recovery. (10) is a heater, which is an element for keeping the temperature of the refrigerant in the container by an external electric heat source, steam or the like.

With the above configuration, when the temperature inside the equipment tank (6) falls below a certain value (T ₁ ), the refrigerant supply / discharge device (8) causes the liquid refrigerant (1) in the equipment tank (6) to be cooled. Transfer to container (7). Further, SF ₆ gas dissolved in the liquid refrigerant (1) which has been transferred is degassed by the gas returning device (9) and sent back into the equipment tank (6).

Further, when the operation is restarted, when the temperature inside the equipment tank (6) reaches the temperature (T ₁ ), the refrigerant supply / discharge device (8)
The liquid refrigerant (1) in the refrigerant container (7) is returned into the equipment tank (6). At this time, if the temperature of the refrigerant is kept at a certain value in advance by the heater (10), the liquid refrigerant (1) returned to the equipment tank (6) will be insulated immediately without absorbing SF ₆ gas. It is possible to shift to cooling with a high yield strength.

The relationship between temperature and gas molecule density in the above operation is the second
As shown by the solid line in the figure, the gas molecular density does not decrease as shown in (a) even when the temperature in the equipment tank (6) becomes T ₁ or lower, and the dielectric strength of the temperature above T ₁ It can be held at the same level as when. In contrast, in the conventional device, the chain line (b)
As shown in, there is no skill to take measures.

The refrigerant supply / discharge device (8) may be, for example, a liquid feed pump, and the gas return device (9) may be, for example, a compressor or a vacuum pump. It is also possible that the compressor or vacuum pump, which is considered as a gas returning device, may also be used as a refrigerant supply / discharge device.

It should be noted that, here, the liquid sending cooling method is taken as an example, but it goes without saying that the same effect can be obtained also in another cooling method, for example, an evaporative cooling method using a condensable refrigerant.

〔The invention's effect〕

As is apparent from the above description, the present invention provides a device for supplying and discharging a liquid refrigerant, a refrigerant container for recovering the liquid refrigerant, a liquid refrigerant discharged from an equipment tank to the refrigerant container, and a liquid refrigerant from the refrigerant container. It is possible to easily prevent the deterioration of the dielectric strength due to the stoppage of the operation of the gas-insulated electromagnetic induction device by providing the refrigerant supply / discharge device for supplying the gas to the device tank and the gas return device for returning the gas from the refrigerant container to the device tank Can
Moreover, the gas-insulated electromagnetic induction device can be miniaturized without designing more insulation than necessary.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of an embodiment of the present invention, FIG. 2 is a refrigerant temperature-gas molecular density characteristic diagram, and FIGS. 3 and 4 are SF ₆ gases of conventional gas-insulated electromagnetic induction devices, respectively. FIG. 3 is a solubility-temperature characteristic diagram and an SF ₆ gas dielectric strength-gas molecule density characteristic diagram. (1) ...... Liquid refrigerant, (2) ...... Liquid transfer pump, (3) ...
… Heat exchanger, (5) …… Device body, (6) …… Device tank, (7) …… Refrigerant container, (8) …… Refrigerant supply / discharge device,
(9) …… Gas return device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichiro Abe 3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Kansai Electric Power Co., Inc. (72) Inventor Koji Nakazawa 651 Tenwa, Ako City, Hyogo Mitsubishi Electric Corporation Ako Manufacturing Co., Ltd. (72) Inventor Tetsuro Hakata 651 Tenwa Tenwa, Ako City, Hyogo Prefecture Mitsubishi Electric Co., Ltd. (56) References JP 59-23508 (JP, A) JP 58-202511 (JP) , A)

Claims (3)

[Claims] 1. A gas insulated electromagnetic induction device using an insulating liquid refrigerant and a non-condensable insulating gas as an insulating and cooling medium, wherein the liquid refrigerant is recovered from a refrigerant container for collecting the liquid refrigerant and an equipment tank. Gas insulation comprising a refrigerant supply / discharge device for discharging to a refrigerant container and supplying the liquid refrigerant from the refrigerant container to the device tank, and a gas returning device for returning gas from the refrigerant container to the device tank. Electromagnetic induction equipment. 2. A gas-insulated electromagnetic induction device according to claim 1, wherein either the compressor or the vacuum pump is also used as a refrigerant supply / discharge device and a gas returning device. 3. The gas-insulated electromagnetic induction device according to claim 1, wherein the refrigerant container has a refrigerant temperature holding function by an external heat source.