JPH0786049A - Stationary induction apparatus - Google Patents

Abstract

PURPOSE:To contrive to improve the cooling performance of a container without increasing the form of the container and the constitution of the container by a method wherein a mixed liquid obtainable by mixing perfluorocarbon liquids, which are different from each other in boiling point, is used as a liquid which is filled in the container. CONSTITUTION:An insulating container 2 is housed in a tank 1 and a transformer main body 50, that is, a core 3 and a winding 4, is arranged in this container 2. Moreover, a liquid 6, which is used as an insulating and cooling medium, is filled in the space on the periphery of the main body 50 arranged in the interior of the container 2. The liquid 6 is led out on the outside of the tank 1 through a piping 8, is circulated by a circulating system of a heat exchanger 9 and a pump 10 and a liquid cooling is performed. As a liquid which is gilled in the space on the periphery of the main body 50, the liquid 6 obtainable by mixing a high-boiling point perfluorocarbon liquid and a low- boiling point perfluorocarbon liquid out of a perfluorocarbon liquid is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a static induction machine, and more particularly to an improvement of a static induction machine filled with a nonflammable liquid.

[0002]

2. Description of the Related Art Generally, in a static induction generator such as a transformer, the inside thereof is filled with an insulating liquid such as mineral oil for the purpose of maintaining insulation of a high voltage portion and cooling a heat generating portion. . Particularly in recent years, from the viewpoint of disaster prevention, nonflammable devices have been required, and nonflammable liquids have been used as insulating and cooling media.

As a static induction electric device filled with a non-combustible liquid, for example, as disclosed in Japanese Patent Laid-Open No. Hei 2-162707, the container is formed in double and the static induction electric device is provided in the inner container. An apparatus in which a main body is housed and a non-flammable refrigerant liquid is filled, and an insulating gas is filled in a tank which is an outer container, and JP-A-3-120706.
As disclosed in Japanese Unexamined Patent Application Publication No. 2004-242242, there is one in which a stationary induction body is arranged in a single container, and a non-combustible liquid serving as an insulating and cooling medium is filled around the main body.

Non-combustible liquids used for these are perchlorethylene, CFC 112, CFC 113.
And a perfluorocarbon liquid having good fluidity by eliminating the flash point and the burning point, and JP-A-62-2
As described in Japanese Patent No. 56306, there are various mixed insulating oils such as Perchlor ethylene type insulating oil mixed with mineral oil type insulating oil of a specific volume ratio, but generally, kinematic viscosity is small, that is, fluidity is low. A perfluorocarbon liquid with good cooling performance is used.

The perfluorocarbon liquid has a kinematic viscosity as small as about 1/10 of that of mineral oil, has excellent characteristics as a cooling medium for circulating cooling, and is capable of high-performance cooling. In particular, it can be said that it is a suitable cooling medium in terms of fluidity for this type of static induction electric generator installed in a cold region.

At present, one of the commercially available perfluorocarbon liquids is, for example, a liquid having a molecular structure of C ₈ F ₁₆ O, and the boiling point of the liquid is naturally determined from the molecular structure. The boiling point of this liquid is about atmospheric pressure. It is 100 ° C. Due to other manufacturing relationships, for example, the boiling point at atmospheric pressure is 130 ° C, 155 ° C, 1
There are liquids such as 74 ° C and 215 ° C.

In practical use, the most suitable liquid for the model is selected from the liquids having different boiling points stepwise.

Although the boiling point of the liquid is determined by its physical properties, the insulation strength is greatly reduced in the boiling state, so it is necessary to maintain the insulation strength by preventing boiling. Conventionally, in order to prevent the liquid from boiling, a flexible separator is provided on the liquid surface, a gas is enclosed, and the liquid is pressurized with the gas.

For example, a perfluorocarbon liquid having a boiling point of about 100 ° C. at atmospheric pressure has a boiling point of 119 ° C. at a gas filling pressure of 0.2 MPa, and the operating temperature does not boil 119.
The temperature is kept below ℃.

[0010]

The static induction electric device using the perfluorocarbon liquid as described above is very effective not only in non-flammability but also in cooling performance. However, selection of the perfluorocarbon liquid is required. On the other hand, when the minimum required filling pressure is 0.2 MPa in terms of the insulation strength of the gas space,
That is, if the strength of the tank is tolerable up to that pressure, if the transformer operating temperature is raised to 120 ° C., the liquid having a boiling point of atmospheric pressure of 100 ° C. cannot be satisfied, and the boiling point of the atmospheric pressure is 130 ° C. I have no choice but to choose a liquid.

When a liquid having a boiling point of 130 ° C. at atmospheric pressure is used, the boiling point at a gas filling pressure of 0.2 MPa is 150.
It will be ℃, which means that the design is extremely uneconomical. That is, a liquid having a high boiling point is more expensive than a liquid having a low boiling point and has a large kinematic viscosity, that is, it has a high pour point and is disadvantageous as an insulating / cooling medium for a transformer.

In this case, of course, if a liquid having a low boiling point is used and the gas pressure sealed in the tank is increased, the boiling point rises in accordance with the vapor pressure characteristic, which is preferable for insulation, but the mechanical strength of the tank itself is increased. Therefore, the shape of the tank may change, and the weight and size may increase.

The present invention has been made in view of the above circumstances, and an object thereof is to increase the container shape and the container size of a static induction machine without using a special liquid, that is, even if an existing liquid is used. It is to provide a static induction electric machine of this kind that has good cooling performance without causing it.

[0014]

That is, according to the present invention, the liquid filled in the container is formed of a mixed liquid of at least two perfluorocarbon liquids having different boiling points, and
The mixing ratio of both liquids is adjusted so as to achieve the intended purpose without using a cooling medium having a predetermined boiling point.

[0015]

[Function] That is, when the liquid is mixed in this way,
The boiling point changes depending on the mixing ratio of the two liquids, that is, the boiling point is low when the ratio of the high boiling point liquid is small, and is high when the ratio is high, so that it can be easily matched with the operating temperature of the static induction electric generator, and therefore, the gas pressure Without increasing
That is, it is not necessary to increase the container shape or container size of the static induction device.

When the mixed liquid is further mixed with a perfluorocarbon liquid having a specific molecular structure and a perfluorocarbon liquid having another molecular structure, the pour point is lower than the pour points of the individual liquids. Since the point becomes low, it becomes effective as a cooling medium, and the cooling performance of electric equipment can be improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 shows an example of a transformer which is one of the static induction generators.

The transformer is mainly composed of a transformer body 50, an outer container (tank) 1, and a heat exchanger 9.

Inside the tank 1, an inner container (insulating container)
2, the transformer main body 50, that is, the iron core 3 and the winding 4 are arranged in the insulating container 2.

Inside the insulating container 2, the transformer main body 50
A liquid (cooling medium) 6 serving as an insulating and cooling medium is filled in the space around it in which is disposed. The transformer body 50 is immersed in the liquid 6.

The liquid 6 is drawn out of the tank 1 by a pipe 8 and circulated by a circulation system of a heat exchanger 9 and a pump 10 to cool the liquid.

On the other hand, the space between the insulating container 2 and the tank 1 is filled with an insulating gas 5 for applying a predetermined pressure to the liquid 6, and the upper part of the insulating container 2 is filled with the liquid 6 and the insulating gas. A stretchable separation film 7 for separating 5 is arranged, and the pressure of the insulating gas 5 enclosed is transmitted to the liquid surface of the liquid 6 through the separation film 7.

As the liquid 6 filled in the space around the transformer main body 50, a perfluorocarbon liquid is used, and in particular, a perfluorocarbon liquid formed as follows is used. That is, among the perfluorocarbon liquids, a liquid (hereinafter referred to as a mixed liquid) 6 in which a high-boiling point perfluorocarbon liquid and a low-boiling point perfluorocarbon liquid are mixed is used.

When the liquid thus formed is used, the vapor pressure characteristic of the high-boiling point perfluorocarbon liquid becomes a curve A, as shown in FIG. 2, which shows the vapor pressure characteristic of the perfluorocarbon liquid. Since the vapor pressure characteristic of the boiling point perfluorocarbon liquid becomes a curve B, the vapor pressure characteristic of the mixed liquid becomes a curve C intermediate between the two.

In the case of a low-boiling point perfluorocarbon liquid alone, at a temperature T at which the liquid does not boil during transformer operation, a pressure PB is required from the vapor pressure characteristic curve B, but a mixed liquid containing a high-boiling point perfluorocarbon liquid is required. Then, boiling can be eliminated by applying a pressure PC lower than that.

That is, it means that the pressure for filling the insulating gas 5 described above may be low, and if the pressure of the filled insulating gas is low, the strength of the tank can be reduced accordingly and the weight of the transformer can be reduced. Is to say.

If the mixing ratio of the high boiling point perfluorocarbon liquid is increased, the C characteristic of FIG. 2 approaches the A characteristic, and if the ratio of the low boiling point perfluorocarbon liquid is large, it approaches the B characteristic. Temperature T by changing
It is possible to change the pressure of the gas filled in and to freely set the pressure according to the operating conditions of the transformer.

The boiling point of the mixed liquid is as shown in FIG. 3, and the boiling point can be changed depending on the mixing ratio. That is,
If the proportion of the high boiling point liquid is small, the boiling point approaches T1, and if it is large, it approaches T2. Therefore, it is possible to obtain a liquid having an arbitrary boiling point by adjusting the mixing ratio.

Further, the pour point of the mixed liquid changes depending on the mixing ratio as shown in FIG. When a perfluorocarbon liquid having a specific molecular structure and a perfluorocarbon liquid having another molecular structure are mixed, the pour point becomes lower than the pour point of each simple substance liquid.

That is, the pour point T4 of the low-boiling point perfluorocarbon liquid alone is the lowest pour point T5 when the high-boiling point perfluorocarbon liquid is mixed into this low-boiling point perfluorocarbon liquid and the proportion is M%. When the mixing ratio is further increased, the pour point rises and the mixing ratio becomes 100
%, The pour point T3 of the high boiling point perfluorocarbon liquid alone
There is a property of becoming.

From this, it can be said that this mixed solution has a lower pour point and is much more effective as a cooling medium than the perfluorocarbon liquid alone in terms of cooling performance.

In particular, a liquid obtained by mixing the high-boiling point perfluorocarbon liquid in the range of 0% to R% in the figure is
It can be used as a liquid in a low flow range that cannot be obtained by each perfluorocarbon liquid alone, and is very suitable as a transformer installed in a cold region.

For example, a commercially available high-boiling point perfluorocarbon liquid having a boiling point of 101 ° C. has a pour point of −65 ° C., and a low-boiling point perfluorocarbon liquid having a boiling point of 160 ° C. has a pour point of −55 ° C. As a result of the experiment, the pour point of the mixed solution when these are mixed has the characteristics shown in FIG.

That is, when the mixing ratio of the low boiling point perfluorocarbon liquid is about 25 to 35%, the pour point is almost the lowest.
The pour point is about 75 ° C., and the pour point is lower than the pour point −65 ° C. of the simple substance of perfluorocarbon liquid having a high boiling point until the mixing ratio is about 70%.

Therefore, by setting the mixing ratio so that it becomes lower than the pour point of each simple liquid, good liquid circulation, that is, cooling of the electric appliance main body, can be performed at the start of operation of the transformer installed in a cold region. it can.

Further, the high-boiling liquid is generally more expensive than the low-boiling liquid, and therefore the cost can be reduced by reducing the mixing ratio of the high-boiling liquid, which is expensive, as shown in FIG. Therefore, it is more economical to use it as an optimum mixed liquid that satisfies the operating conditions of the transformer.

Further, the kinematic viscosity of the high-boiling point perfluorocarbon liquid is larger than that of the low-boiling point perfluorocarbon liquid, and the characteristics shown in FIG. 6 are obtained depending on the mixing ratio. It changes as it approaches the liquid side. Therefore,
If a single high boiling point liquid is selected based only on the superiority of the boiling point, the cooling efficiency will be reduced.Therefore, it is necessary to prepare a mixed liquid that does not reduce the cooling efficiency. Design can be done.

In the description of the present invention, the case where the transformer main body is arranged in the double container has been described, but the transformer (static induction generator) always formed in this way is described.
It does not have to be, and the present invention can be adopted even if it has a single container.

FIG. 8 shows one example thereof. A transformer main body in which a winding 4 is wound around an iron core 3 is housed in a tank 1, and a mixed liquid 6 of perfluorocarbon liquid is filled in the tank. A conservator 15 for absorbing expansion and contraction of the liquid is provided on the upper part of the tank, and a separator 16 for separating the expandable liquid and the gas is attached to the liquid surface. This liquid surface is operated at almost atmospheric pressure and not pressurized.

A cooler 9 is provided outside the tank 1 to cool the liquid naturally.
In this case, the mixed liquid 6 of the high-boiling point perfluorocarbon liquid and the low-boiling point perfluorocarbon liquid has the characteristics that the specific gravities do not differ greatly and that they cannot be easily separated once mixed and stirred, which is also advantageous in this respect.

That is, the mixed liquid is prepared so that the stirring and mixing are sufficiently performed by natural circulation. For example, the ratio of specific gravity ((specific gravity of liquid A) / (specific gravity of liquid B)) is 1.05.
In the following cases, a mixed liquid having a boiling point freely changed as described above can be obtained, and a liquid transformer having a boiling point optimum for operating conditions can be obtained.

When a liquid having a specific gravity ratio of 1.05 or more is mixed at a weight ratio of 50:50, the boiling point varies greatly, and it becomes difficult to obtain an optimum mixed liquid. However, in the operating transformer, the higher the load current and the higher the temperature, the larger the temperature difference between the inlet and outlet of the cooler, and the smaller the kinematic viscosity, and the more vigorous the mixing and stirring. Be done.

As a result, a uniform mixed liquid is formed and the liquid is unlikely to be separated. Further, if the mixing ratio is determined with the lowest value of the boiling point of the mixed solution as a guide, the transformer can be optimized as a solution having an intermediate boiling point.

As described above, according to the present invention, by mixing liquids having different boiling points to form a liquid having an intermediate boiling point and using it as an insulating / cooling medium for a static induction electric machine, the gas filling pressure can be reduced. As a result, the strength of the stationary induction tank can be reduced.

Further, by adjusting the mixing ratio of the liquids, it is possible to obtain a liquid having a boiling point suitable for the operating conditions of the static induction electric device, so that it is possible to provide an economical static induction electric device with good cooling efficiency.

Furthermore, by using a mixed solution, it is possible to obtain a solution having a pour point lower than the pour point of the simple substance solution,
It is possible to provide a static induction generator suitable for installation in a cold region.

[0047]

As described above, according to the present invention, it is possible to cool without using a special liquid, that is, without using the existing liquid, without increasing the container shape or the container size of the static induction machine. It is possible to obtain a static induction electric machine of this kind with good performance.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a static induction generator of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between vapor pressure and temperature of a liquid filled in a container.

FIG. 3 is a characteristic diagram showing a relationship between a mixing ratio of a liquid filled in a container and a boiling point.

FIG. 4 is a characteristic diagram showing the relationship between the mixing ratio of the liquid filled in the container and the pour point.

FIG. 5 is a characteristic diagram showing changes in the pour point depending on the mixing ratio of the liquid filled in the container.

FIG. 6 is a characteristic diagram showing the relationship between the mixing ratio of the liquid filled in the container and the kinematic viscosity.

FIG. 7 is a characteristic diagram showing a relationship between a mixing ratio of liquid filled in a container and a price.

FIG. 8 is a vertical sectional side view showing another embodiment of the static induction generator of the present invention.

[Explanation of symbols]

1 ... Tank, 2 ... Insulation container, 3 ... Iron core, 4 ... Winding, 5 ...
Insulating gas, 6 ... Mixed liquid, 7 ... Liquid / gas separation membrane, 8 ... Piping, 9 ... Cooler, 10 ... Pump, 1 ... Tank, 12 ... Iron core, 13 ... Winding, 14 ... Mixed liquid, 15 ... beta,
16 ... Separator, 9 ... Cooler, 50 ... Transformer body.

Front Page Continuation (72) Inventor Kiyoto Hiraishi 1-1-1 Kokubuncho, Hitachi City, Ibaraki Hitachi Kokubun Plant, Hitachi Ltd.

Claims (8)

[Claims] 1. An iron core and a winding are housed in a container, and a space in the container is filled with an incombustible liquid, and the liquid is formed so as to cool the iron core and the winding. The static induction electric device according to claim 1, wherein a mixed liquid in which two or more perfluorocarbon liquids having different boiling points are mixed is used as the liquid filled in the container. 2. An iron core and a winding are housed in a container, and a space in the container is filled with a non-combustible liquid, and the liquid is used to cool the iron core and the winding. In the static induction electric device, a mixed liquid in which at least two perfluorocarbon liquids having different molecular structures are mixed is used as the liquid filled in the container. 3. A static induction machine in which an induction body is housed in a container, and a space inside the container around the induction machine body is filled with a non-combustible and insulative cooling medium. A static induction electric device characterized by being formed of a mixed liquid of at least two perfluorocarbon liquids having different boiling points. 4. A static induction machine in which a main body of an induction machine is housed in a container, and a space around the main body of the induction machine is filled with a non-combustible and insulating cooling medium, wherein the cooling medium has an operating temperature. A static induction electric machine characterized by using a mixed liquid of a perfluorocarbon liquid having a molecular structure having a higher boiling point and a perfluorocarbon liquid having a molecular structure having a lower boiling point than an operating temperature. 5. A static induction machine in which an induction body is housed in a container, and a space inside the container around the induction machine body is filled with a non-combustible and insulative cooling medium. A static induction, characterized in that it is formed of a mixed liquid of at least two perfluorocarbon liquids having different boiling points, and a mixing ratio of both liquids is mixed to form a cooling medium having a boiling point near the operating temperature and having a boiling point higher than the operating temperature. Electric appliances. 6. A static induction machine in which an induction body is housed in a container, and a space inside the container around the induction machine is filled with a non-flammable, insulating cooling medium, wherein the cooling medium is the operating temperature of the electric appliance. It is characterized in that a perfluorocarbon liquid having a higher boiling point temperature and a perfluorocarbon liquid having a lower boiling point temperature than the electric appliance operating temperature are mixed to prepare a liquid having a boiling point slightly higher than the electric appliance operating temperature. And a stationary induction machine. 7. A stationary system in which an induction body is housed in a container, and a space inside the container around which the inductive device body is housed is filled with a non-combustible and insulating cooling medium, and the cooling medium is hermetically sealed in a compressed state. In the induction electric machine, as the cooling medium, a perfluorocarbon liquid having a boiling point temperature higher than the operating temperature and a perfluorocarbon liquid having a boiling point temperature lower than the operating temperature are mixed to form a perfluorocarbon liquid having an intermediate boiling temperature. A static induction electric machine characterized in that a fluorocarbon liquid is used, and the boiling point temperature in the middle is a boiling point temperature at which the cooling medium under pressure does not evaporate at the operating temperature. 8. A static induction machine in which an induction body is housed in a container, and a space inside the container around the body of the induction machine is filled with a non-combustible insulating insulating medium under pressure, As a medium, while using a liquid obtained by mixing a perfluorocarbon liquid having a lower boiling point than the operating temperature and a perfluorocarbon liquid having a higher boiling point than the operating temperature, the mixing ratio of the liquid temperature at the time of operation in the pressurized state of the cooling medium A static induction electric device characterized by being adjusted to a rate that does not boil.