JPH01166516A - Gas-insulated transformer - Google Patents

Abstract

PURPOSE:To reduce the variations in internal pressure due to a change in temperature by filling a vessel, which houses a coil and an iron core, with a perfluorocarbon fluid as a cooling/insulating medium, and employing as the insulating gas C2F6 gas or a mixture gas specified by the C2F6 gas. CONSTITUTION:A tank 1 is separated into a fluid part of a cooling/insulating medium 2 and a gas part of C2F6 gas 3. An iron core 6 composed of laminated silicon steel sheets, and high and low voltage wirings 4, 5 are housed in an insulation cylinder partition plate 7, which separates the tank from the gas part of the C2F6 gas 3. Perfluorocarbon fluide is charged as the medium 2. A mixture gas composed of at least one or more of N2, He, and Ar gases and of the C2F6 gas may be available as the C2F6 gas 3. Thus, a change in the solubility of the gas with respect to a change in the temperature can be reduced to keep the tank substantially unchanged, thereby assuring a small-sized tank.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas insulated transformer, in particular, the core and coil are immersed in a cooling and insulating medium, and C2FB gas or CZ
The present invention relates to a transformer having a sealed tank structure filled with a mixed gas mainly consisting of FB gas.

[Conventional technology]

Conventional gas insulated transformers are as described in JP-A-56-107527 and JP-A-56-107531.
A cooling/insulating medium of CaFxeO is sprayed from the top of the core and the windings to cool them using the latent heat of vaporization of the cooling/insulating medium.
Furthermore, SFe gas is sealed in the gas space to maintain insulation. In a gas insulated transformer that sprays such an insulating medium, the amount of cooling/insulating medium used is small, the volume of the gas space is large relative to the amount of medium, and the amount of SFe gas dissolved in the cooling/insulating medium is not too large. It's not a problem.

On the other hand, in spray-type gas insulated transformers, the iron core is not only made of concentric cylinders, but also has a complex structure, making it difficult to spray refrigerant evenly over the entire core. This has the disadvantage that the local temperature of the iron core increases. Further, the winding also has the disadvantage that magnetic flux leaks in the outer circumferential direction, making it impossible to eliminate temperature imbalance in the entire vertical direction. For this reason, a problem arises in that sufficient cooling performance cannot be obtained by simply spraying the cooling/insulating medium, and local overheating is likely to occur.

[Problem that the invention seeks to solve]

In a gas insulated transformer that uses a perfluorocarbon liquid such as C2FB gas as the cooling/insulating medium and SFe gas as the insulating gas, the SFe gas has a perfluorocarbon liquid of about 2000Vo1% to 170Vo1% at 120℃ to 100℃ under atmospheric pressure. Dissolves in fluorocarbon liquid.

For this reason, in a transformer, the pressure in the space above the perfluorocarbon liquid decreases at low temperatures (0"C to -20C), and there is a problem that the dielectric breakdown characteristics also deteriorate.In addition, at high temperatures (80C to 100C) When the temperature becomes low (0℃~-20℃)
℃), the SFe gas dissolved in the perfluorocarbon liquid diffuses into the space above the perfluorocarbon liquid, and the pressure inside the transformer increases significantly. It is necessary to increase the space volume. Furthermore, there was a problem in that the amount of gas leakage increased significantly as the internal pressure increased.

In the gas insulated transformer of the present invention, the core and windings are constantly immersed in a cooling/insulating medium, and as described above, local overheating of the core and windings is less likely to occur. However, compared to the spray method, the amount of cooling/insulating medium used is large, the volume of the gas space is small relative to the amount of medium, and the amount of SFe gas dissolved in the cooling/insulating medium and its temperature change are large, resulting in internal pressure fluctuations. is larger than that of the spray method, and requires an insulating gas that is difficult to dissolve in the cooling and insulating medium. Furthermore, some of the cooling/insulating medium volatilizes and tends to remain at the bottom of the tank, so it is necessary to suppress volatilization and evaporation of the refrigerant.

An object of the present invention is to provide a small, highly reliable gas insulated transformer that has small internal pressure fluctuations due to temperature changes, suppresses volatilization and evaporation of refrigerant, and is free from local overheating.

[Means for solving problems]

The above problem consists of a sealed tank, an iron core housed in the tank and made of laminated silicon steel plates, a coil wound around the iron core, and a cooling/insulating medium that cools the front coil and the iron core. In a gas insulated transformer equipped with an insulating gas that maintains the insulation properties of the coil, a container is provided for storing the coil and the iron core, and the container is filled with a perfluorocarbon liquid as the cooling/insulating medium. , the insulating gas is C2Fg gas or CzFe gas and NZ.

By using a mixed gas consisting of at least one or more of He and Ar gases, and further providing a medium sealing body at the interface between the cooling/insulating medium and the insulating gas to suppress volatilization/evaporation of the cooling/insulating medium. resolved.

[Effect]

A container for storing the iron core and coil is provided in a sealed tank, and a cooling/insulating medium is filled in this container to uniformly cool the transformer.

CzFts gas and N2. At least one of He, Ar gas
By combining the mixed gas consisting of the above, or the C, i F 6 gas, and the perfluorocarbon liquid, the amount of dissolved gas does not change much with respect to temperature changes, and the pressure inside the tank can be maintained at approximately constant pressure.

Further, a medium sealing body is provided at the interface between the cooling/insulating medium and the mixed gas or the Cz Fe gas,
Suppress volatilization and evaporation of the cooling/insulating medium.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIG.

The inside of the tank 1 was divided into a liquid part containing a cooling/insulating medium 2 and a gas part containing CaFe gas 3. By doing this, it becomes possible to store the high and low voltage windings 4.5 and the iron core 6 in the liquid part and immerse them in the cooling/insulating medium 2, thereby cooling the iron core 6 using the silicon steel plate. It has a good effect and can be cooled uniformly. That is, the iron core 6, which is a heating element, and the high and low voltage windings 4 and 5 are integrated into Ca.
It is stored in an insulating cylindrical partition plate (insulating container) 7 that separates the Fe gas 3 from the gas portion. A cooling/insulating medium 2 is filled in this. Liquid feeding pump 8 that cools and circulates this cooling/insulating medium 2
and a cooler 9 are connected to the tank 1. By doing this, the iron core 6 is placed in the cooling/insulating medium 2 within the insulating partition plate 7.
to prevent local overheating. The cooling/insulating medium 2 within the insulating cylindrical partition plate 7 evaporates and partially remains at the bottom of the tank 1, but this medium is returned to the insulating cylindrical partition plate 7 by the liquid feed pump 8'. In the embodiment of FIG.
For example, perfluorocarbon CaF14Q is used as a cooling/insulating medium, and SFe gas and C2, FB are used in the insulating gas part.
Table 1 shows the relationship between the amount of gas dissolved and the temperature when gas is used. As is clear from the table, it can be seen that the temperature changes in the amount of dissolution and the internal pressure are much smaller when CaFe gas is used than when SFe gas is used. As a result, the volume of the pressure adjustment chamber 10 and the CaFe gas 3 portion can be reduced.

Table 1: Perfluorocarbon liquid 1o00Q, gas space 12
The pressure of a sealed tank of 5 liters (combined with gas filled at 1 atm at 20°C) Furthermore, since the medium sealing liquid 11 seals the liquid upper part of the cooling/insulating medium 2°2', the refrigerant The volatilization and evaporation of the liquid are suppressed, and in particular, the liquid feeding pump 8' can be made smaller.

Next, a second embodiment of the present invention will be described using FIG. 2. In place of the medium sealing liquid 11 in FIG. 1, a medium sealing material 12 which is a solid material with holes having a specific gravity lower than that of the refrigerant is used. Similarly, the iron core 6 and the high and low voltage windings 4 and 5 are efficiently and uniformly cooled, and since the gas space is filled with C2Fe gas 3, internal pressure fluctuations are small, and the pressure adjustment chamber 10
Also, since the volume of the gas space is reduced and the medium sealing material 12 is used, the liquid pump 8' can be made smaller.

The gas insulated transformer filled with CzFa gas of the present invention includes:
Not only CzFa gas can be used as an insulating gas.

Gases such as Nz, He, Ar, etc. whose solubility in perfluorocarbon liquid is approximately the same level or less as C2F6 gas are
It may be mixed with zF a gas.

As the cooling/insulating medium used in the present invention (1 g of perfluorooctane n-CaF (boiling point 103°C) that does not easily dissolve 2FB gas and has a boiling point of 150°C or lower, perfluorononane n-CeFzo (boiling point 128°C), perfluorocyclic Ether type Cyclo-C7F140 (boiling point 81
°C), Cyclo-CaFisO (boiling point 103 °C)
Besides (CaP2)a, (boiling point 113°C).

(CaF@)aN (boiling point 143℃)s (CaFe
) A liquid mixture of sN and Cyclo-C8F180 (boiling point 105-140°C) can be used.

In addition, as a media sealing liquid, 1,2,6-hexanetriol and 3-methyl-1,3,5-pentanetriol that do not dissolve in perfluorocarbon liquid, polyhydric alcohols with more than 2 valences, dimethylsiloxane, methylphenylsiloxane, etc. Silicone oil etc. are suitable.

As a media sealant, materials such as perforated sheets and plates with a specific gravity lower than that of the refrigerant can be used, such as thermoplastics such as TPX (poly4-methylpenlan-1) and PET (polyethylene terephthalate), and thermosetting materials such as epoxy and phenol. Resin material with good refrigerant resistance can be used.

〔Effect of the invention〕

A container for storing the iron core and coil is provided in a sealed tank, and a cooling/insulating medium is filled in the container to uniformly cool the transformer. Insulating gas sealed in the tank,
Namely, C2FB gas and NZ.

By using a mixed gas consisting of at least one of He and Ar gases, or a combination of CzFe gas and perfluorocarbon liquid, the amount of dissolved gas does not change much with temperature changes, and the pressure inside the tank is maintained at an almost constant level. This has the effect of making the tank smaller.

Furthermore, by providing a medium sealing body at the interface between the cooling/insulating medium and the insulating gas, it has the effect of suppressing volatilization and evaporation of the cooling/insulating medium, making it a highly reliable, compact gas-insulated transformer with little pressure fluctuation. It can be used as a container.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of a gas insulated transformer according to the present invention, and FIG. 2 is a diagram showing a second embodiment of a gas insulated transformer according to the present invention. 1...Tank, 2...Cooling/insulating medium, 3...C
Z F s gas, 4, 5... coil, 6... iron core,
11... Medium sealing liquid, 12... Medium sealing material.

Claims (7)

[Claims] 1. A sealed tank, an iron core housed in the tank and made of laminated silicon steel plates, a coil wound around the iron core, and a cooling/insulating medium that cools the coil and the iron core.
In a gas insulated transformer equipped with an insulating gas that maintains the insulation properties of the coil, a container is provided for storing the coil and the iron core, and the container is filled with a perfluorocarbon fluid as the cooling/insulating medium. , the insulating gas is C_2F_6 gas or C_2F_6 gas and N_2,
A gas insulated transformer characterized by using a mixed gas consisting of at least one of He and Ar gases. 2. The perfluorocarbon liquid is n-C_8F_
1_8, n-C_9F_2_0, Cyclo-C_7F
_1_4O, Cyclo-C_8F_1_6O, (C_
3F_7)_3, (C_4F_9)_3N, (C_3F
_9) The gas insulated transformer according to claim 1, wherein the gas insulated transformer is any one of a mixed liquid of _3N and Cyclo-C_8F_1_6O. 3. A sealed tank, an iron core housed in the tank and made of laminated silicon steel plates, a coil wound around the iron core, and a cooling/insulating medium that cools the coil and the iron core.
In a gas insulated transformer equipped with an insulating gas that maintains the insulation properties of the coil, a container is provided for storing the coil and the iron core, and the container is filled with a perfluorocarbon liquid as the cooling/insulating medium. , the insulating gas is C_2F_6 gas or C_2F_6 gas and N_2,
A mixed gas consisting of at least one of He and Ar gases, and a medium sealing body for suppressing volatilization and evaporation of the cooling/insulating medium is provided at the interface between the cooling/insulating medium and the insulating gas. gas insulated transformer. 4. The perfluorocarbon liquid is n-C_8F_
1_8, n-C_9F_2_0, Cyclo-C_7F
_1_4O, Cyclo-C_8F_1_6O, (C_
3F_7)_3, (C_4F_9)_3N, (C_3F
_9) The gas insulated transformer according to claim 3, wherein the gas insulated transformer is any one of a mixed liquid of _3N and Cyclo-C_8F_1_6O. 5. The medium sealing body contains at least one compound selected from 1,2,6-hexanetriol, 3-methyl-1,3,5-pentanetriol, or a polyhydric alcohol having a valence of 2 or more. The gas insulated transformer according to claim 3, characterized in that the gas insulated transformer contains a sealing liquid. 6. The gas insulated transformer according to claim 3, wherein the medium sealant is a sealing liquid containing one or both of dimethylsiloxane and methylphenylsiloxane, which are silicone oils. . 7. 4. A gas insulated transformer according to claim 3, wherein said medium sealing body is a solid plastic material having a specific gravity smaller than that of said cooling/insulating medium.