JPH1116742A - Stationary induction device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In order to cool an iron core and windings, an insulating gas circulating in a transformer tank and a cooler by a blower is used to reduce heat generated in the iron core clamp by magnetic flux leakage from the windings. Effectively deprives and reduces temperature rise. An upper or lower iron core fastener has a hollow cooling path structure having a space therein, and the cooling path is connected to an upper or lower pipe in at least one place, and the upper or lower part of the tank is connected in at least one place. It is configured to communicate with the lower space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a stationary induction apparatus, in particular, to a cooling structure for fitting with a suitable core clamping the gas insulated transformer using an insulating gas as an insulating and cooling medium such as SF ₆ gas .

[0002]

2. Description of the Related Art Conventionally, static induction devices such as transformers are
The oil-insulated type, which mainly uses insulating oil for insulation and cooling, occupies the mainstream. However, in the case of oil-filled electrical equipment, there is a risk of fire or the like caused by oil when an accident occurs. In particular, in recent years, substation facilities such as transformers have often been installed underground in buildings or in urban areas due to restrictions on installation locations in cities, and disaster prevention measures have become an important issue.

[0003] Therefore, a gas insulated transformer using non-flammable gas, which does not cause a fire and is highly safe, as an insulating and cooling medium instead of insulating oil, has tended to be adopted. The demand for conversion is increasing.
However, the insulating gas has a disadvantage in that the physical properties related to cooling, such as density, specific heat, and thermal conductivity, are smaller than that of the insulating oil, and the cooling performance is inferior. Therefore, the gas-insulated transformer has a structure in which an insulating gas is forcibly flown inside the iron core and the windings to enhance the cooling performance.

FIG. 9 shows an example of a transformer having such a cooling structure.
Shown in Reference numeral 1 denotes a transformer tank, in which a transformer 1 comprising an iron core 2 and a winding 3 wound around the iron core 2 is housed, and an insulating gas 4 is supplied in the tank 1 at a specified pressure. It is enclosed. A partition plate 5 is provided inside the tank 1 so that as much insulating gas 4 as possible flows through the iron core 2 and the windings 3. The inside of the tank 1 is divided into an upper space 6 and a lower space 7. I have. Reference numerals 8a, 8b and 9a, 9b denote upper and lower iron core fasteners, respectively, which clamp the iron core 2 from both sides thereof in the laminating direction and mechanically hold it. Reference numeral 10 denotes a cooler, which is connected to the upper space 6 via the upper pipe 12. The lower space 7
Are connected by a lower pipe 13 via a blower 11.

As for the flow of the insulating gas 4, the insulating gas 4 sent out by the blower 11 flows into the tank lower space 7 through the lower pipe 13 as shown by an arrow, and then flows through the iron core 2 and the inside of the winding 3. It passes through to the tank upper space 6. The lower space 7 of the tank and the upper space 6 of the tank
The insulating gas 4 does not flow outside the winding 3 at this time. When passing through the iron core 2 or the windings 3, the insulating gas 4, which cools them and deprives them of heat, raises the temperature.
After passing through 2, it is sent to a cooler 10, where it is cooled and then sucked into a blower 11. Then, in the same manner as described above, the circulation in which the air is sent out again to the tank lower space 7 through the lower pipe 13 by the blower 11 is repeated. As described above, the iron core 2 and the windings 3 are cooled by coming into contact with the forced flow of the insulating gas 4 by the blower 11, and are kept below the allowable limit.

[0006] However, iron core fasteners 8a, 8b, 9
Most of the a and 9b are not in contact with the forced flow of the insulating gas 4 by the blower 11, despite the heat generated by the eddy current when the leakage magnetic flux from the winding 3 enters,
The cooling is only natural convection. For this reason, there has been a problem that the temperature rise of the core fasteners 8a, 8b, 9a, 9b is large. In addition, the increase in capacity and miniaturization of the transformer causes an increase in leakage magnetic flux that enters the iron core fasteners 8a, 8b, 9a, and 9b, and as a result, the amount of heat generated by eddy current increases. Performance could not be obtained, which was a practical obstacle.

In order to solve this problem, a method for improving the cooling performance of the iron core fastener is disclosed in Japanese Patent Laid-Open No. 3-1297.
No. 11 publication. In addition to cooling the windings by the above-mentioned insulating gas, the structure sends a liquid cooling medium by a pump to an iron core fastener which is hollow so as to have a space inside, and cools the iron core from the inside, The liquid cooling medium whose temperature has risen is circulated through a cooler outside the tank.

[0008]

With such a structure, the iron core clamp is cooled by forced convection having a large heat transfer coefficient with a liquid cooling medium having better cooling characteristics than the insulating gas. The cooling performance is improved, and the temperature rise of the iron core fastener can be reduced.

However, in addition to the blower and the cooler for circulating the insulating gas, it is necessary to provide a piping system including a pump and a cooler for circulating the liquid cooling medium, which increases the number of parts and increases the installation area. And there is a problem that causes an increase in production cost. In addition, if the liquid cooling medium leaks, the cooling performance is greatly reduced, so that it is necessary to completely keep confidentiality.

[0010] An object of the present invention is to use an insulating gas circulating in a transformer tank and a cooler by a blower to cool an iron core and windings, and to generate a magnetic flux leaking from the windings into the iron core clamp. It is an object of the present invention to provide a highly reliable transformer by effectively removing the heat generated by the heat exchanger and suppressing the temperature rise.
Another object of the present invention is to provide a static induction device, for example, a transformer, which can obtain sufficient cooling performance even for a large capacity and a small size.

[0011]

The stationary induction electric device according to the present invention comprises a lower iron core fastener having a hollow channel structure having a space therein, and connecting the channel to the lower pipe at at least one place. At least one place communicates with the lower space of the tank, and / or an upper core fastener has a hollow flow path structure having a space inside, and the flow path is connected to the upper pipe at at least one place. With
This is achieved by communicating with the head space in at least one place.

That is, in such a structure, before the insulating gas sent out by the blower flows into the lower space of the tank from the lower pipe, a part of the insulating gas is always provided inside the lower core fastener. Because of the flow, the lower core fastener is deprived of heat by forced convection of the insulating gas and cooled.
Alternatively, at least a part of the insulating gas flowing out of the tank upper space to the upper pipe flows through a flow path provided inside the upper core fastener before reaching the upper pipe, and the upper core fastener is insulated. Cooled by forced convection of gas.

In general, the forced convection heat transfer coefficient is about one order of magnitude larger than the natural convection heat transfer coefficient, so that the cooling performance is improved, and the heat generated in the core clamp by the magnetic flux leaking from the windings is reduced. Since the power can be effectively removed and the temperature rise can be reduced, the reliability of the transformer can be improved. In addition, sufficient cooling performance can be obtained even when the capacity and size of the transformer are increased.

Further, in the forced convection cooling, the heat transfer coefficient can be changed by controlling the flow rate of the insulating gas, so that the structure and dimensions can be determined according to the calorific value of the core clamp. become.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. 1 to 4 taking a single-phase center core type transformer as an example. FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, and FIGS. 3 and 4 are AA section and BB section of FIG. 1, respectively.

Reference numeral 1 denotes a transformer tank, in which the contents of a transformer comprising an iron core 2 and a winding 3 wound around the iron core 2 are accommodated, and an insulating gas 4 is stored in the tank 1. It is sealed at the specified pressure. Further, as much insulating gas 4 as possible is contained in the tank 1 inside the iron core 2 and the winding 3.
A partition plate 5 is installed so as to flow through the inside of the tank 1
The inner upper space 6 and the lower space 7 are separated so as not to communicate with each other. Reference numerals 8a and 8b and 9a and 9b denote upper and lower iron core fasteners, respectively, which clamp the iron core 2 from both sides thereof in the laminating direction and hold the iron core 2 so that the iron core 2 can be raised.

Upper and lower iron core fasteners 8a, 8b, 9
Reference numerals a and 9b denote rectangular cross sections each having a space therein, and have a structure in which hollow box-shaped cooling passages 14a, 14b, 15a, and 15b are formed. That is, the two metal core fasteners are disposed at both ends of the iron core and along the left and right side surfaces of the ends from the front surface to the rear surface of the paper surface, and the cooling passage formed in the metal core fastener is shown in FIGS. As described above, the air passage penetrates from the front surface side to the back surface side, and an entrance is formed in the middle, and the cooling passage from the entrance to both ends of the cooling passage has a linear shape.

Reference numeral 10 denotes a cooler, which is provided outside the tank 1 as shown in FIG. The cooler 10 is provided with cooling passages 15 a, 15 a provided in the lower iron core fastening fittings 9 a, 9 b by a lower pipe 13 via a blower 11 installed outside the tank 1.
b and its four ends. Further, cooling passages 15a, 15 provided in the lower iron core fasteners 9a, 9b.
b communicates with the lower space 7 of the tank via openings 17a and 17b opened in the center. Further, the cooler 10 is also connected to cooling paths 14a and 14b provided in the upper fasteners 8a and 8b at four ends thereof via the upper pipe 12. The cooling passages 14a, 14b provided in the upper core fastening members 8a, 8b communicate with the upper space 6 of the tank through openings 16a, 16b opened in the center thereof.

Next, the cooling operation of this embodiment will be described.

Referring to the flow of the insulating gas 4, the insulating gas 4 sent out by the blower 11 passes through the lower pipe 13 from the four ends of the lower iron core fasteners 9 a, 9 b to the cooling gas provided therein. It flows into roads 15a and 15b. While traveling from the ends to the center in the cooling passages 15a, 15b, the insulating gas 4 performs forced convection cooling of the lower core fasteners 9a, 9b, and thereafter, the openings 17a, 17b opened in the center.
It flows out from 17b toward the lower space 7 of the tank. The insulating gas 4 spread in the lower space 7 of the tank changes its direction upward, and the cooling channels 2Y, 3Y formed in the iron core 2 and the windings 3.
To the upper space 6 of the tank. Since the lower space 7 of the tank and the upper space 6 of the tank are not connected by the partition plate 5, the insulating gas 4 does not flow outside the winding 3. Therefore, the cooling of the iron core 2 and the windings 3 is performed efficiently.

From the upper space 6 of the tank, as opposed to the lower part, openings 16a and 16b provided at the center of the upper fasteners 8a and 8b are provided with cooling passages 14 formed therein.
The insulating gas 4 flows into the cooling passages 14a, 1b.
It is sent to the cooler 10 through the upper pipe 12 through 4b. When flowing through the cooling passages 14a, 14b of the upper core fasteners 8a, 8b, the insulating gas 4 also removes heat generated in the upper core fasteners 8a, 8b from inside by forced convection and cools. After cooling the core 2, the windings 3 and the upper and lower core fasteners 8 a, 8 b, 9 a, 9 b, the insulating gas 4 whose temperature has risen is cooled by the cooler 10 and then the blower 1
It is sucked into 1. Then, the circulation that is sent out again by the blower 11 is repeated as described above.

Thus, the upper and lower iron core clamps 8 are formed.
a, 8b, 9a and 9b are cooled by forced convection having a heat transfer coefficient approximately one digit higher than natural convection by using an insulating gas 4 for cooling the iron core 2 and the winding 3; Of the upper and lower iron cores 8a, 8b, 9
a, 9b heat is effectively taken away,
Since the temperature rise can be kept small, a highly reliable transformer can be manufactured. Also, with the increase in capacity and miniaturization of transformers, upper and lower iron core fasteners 8a, 8
Even if the amount of heat generated by the eddy current generated in b, 9a, 9b increases, sufficient cooling performance can be obtained.

Further, since the cooling path formed in the core clamp has a shape in which the insulating gas flows linearly from the inlet to the outlet, unlike the conventional cooling path in which local heating occurs, the insulating gas is supplied to any of the cooling paths. The flow velocity and flow rate are even at the place,
Generated heat can be dispersed. As a result, the deterioration due to the temperature of the insulating gas 4 is delayed because local heating does not occur, so that the life of the insulating gas 4 can be made longer than the conventional insulating gas. Also, the parts near the iron core fasteners are less likely to be damaged by heat.

The amount of heat generated by the eddy current caused in the core fasteners 8a, 8b, 9a, 9b by the intrusion of the leakage magnetic flux from the winding 3 depends on the positional relationship with the winding 3, the shape, and the like.
Since it differs depending on the dimensions, etc., the upper iron core fastener 8a,
The calorific value of 8b and the calorific value of lower iron core fasteners 9a and 9b naturally differ. If the cooling performance of one of the core clamps can be achieved by a conventional structure, that is, most of the core clamps are cooled only by natural convection, the present invention is applied only to the other core clamp. Needless to say, the structure described above may be applied.

In forced convection cooling, the heat transfer coefficient can be controlled by changing the flow rate of the insulating gas 4. For this reason, the entire amount of the insulating gas 4 is supplied to the iron core fasteners 8a, 8b, 9a, 9b.
When there is room for cooling performance when flowing through the flow paths 14a, 14b, 15a, and 15b, a bypass that directly connects the upper pipe 12 and the upper space 6, and the lower pipe 13 and the lower space 7 is provided, and the iron core fasteners 8a, Cooling path 14 for 8b, 9a, 9b
A, 14b, 15a, and 15b may be flowed at a flow rate necessary for cooling, and the remaining may be flowed to a bypass.

As a specific structure of the bypass, a hole is formed in a side surface of the upper pipe 12 or the lower pipe 13 so as to directly communicate with the upper space 6 or the lower space 7, respectively, or a method as shown in FIG. Conceivable. Since the same structure can be applied to the upper part and the lower part, only the upper part will be described. However, the flow direction of the insulating gas 4 is reversed between the upper part and the lower part.

The upper pipe 12 is made up of upper core clamps 8a, 8
b, and communicates with the cooling passages 14a and 14b through a gap, and the gap communicates with the tank upper space 6. And
The upper pipe 12 is a cooling passage 1 for the upper core fasteners 8a and 8b.
The size is larger than 4a and 14b. Cooler 10
The amount of insulating gas 4 sent out from the tank upper space 6 is cooled by the cooling passage 1 in an amount necessary for cooling the upper iron core fasteners 8a and 8b.
4a, 14b, and the rest directly through the gap,
It flows out to the upper pipe 12.

By doing so, it is possible to reduce the pressure loss while maintaining the cooling performance of the upper core fasteners 8a and 8b. Adjustment of the flow rate flowing into the cooling passages 14a and 14b and the flow rate flowing out of the gap into the tank upper pipe 12 is performed by adjusting the gap between the gaps and the upper pipe 12 and the flow path 14.
This can be performed with a difference in the sizes of a and 14b. Therefore, the upper pipe 12 and the cooling passages 14a and 14b of the upper core fasteners 8a and 8b may have the same size. As described above, the upper pipe 12 fixed to the tank 1 and the cooling passages 14a and 14b are arranged apart from each other.

The reason for this will be described when the contents of the transformer are arranged in the tank 1. First, the tank 1 is divided into an upper tank Y1 and a lower tank Y2 via a flange 1X, and a transformer is disposed in the lower tank Y2. In this case, the cooling passages 14a and 14b are attached to the contents of the transformer. Upper tank Y with upper piping 12 attached
1 is lifted by a crane, and while descending the crane, the upper tank Y1 contacts the flange 1X of the lower tank Y2 so as to cover the contents of the transformer.
a, 14b, the upper piping 1
2 and the cooling passages 14a and 14b can be prevented from being broken without colliding.

For this reason, the upper tank Y1 is connected to the lower tank Y
2, the worker moves the upper pipe 12 and the cooling path 14
Since there is no danger of collision with a and 14b, the lowering work was easily performed without becoming nervous, and the work efficiency was significantly improved. Thereafter, the upper tank Y1 and the lower tank Y2, which are in contact with each other, are integrated by tightening them with bolts and nuts via a security seal. Upper pipe 12 also has flange 12
Since the upper tank Y1 and the lower tank Y2 are integrated because they are divided via the X, the upper pipe 12 is also integrated similarly to the tank.

When the upper pipe 12 is not mounted on the upper tank Y1, the diameter of the upper pipe 12 is made larger than the diameter of the cooling passages 14a and 14b as shown in FIG. The upper pipe 12 is inserted into the cooling passages 14a and 14b from Y1 to facilitate the dimensional adjustment. Further, conversely, if the diameter of the cooling passages 14a and 14b is made larger than that of the upper pipe 12, the upper tank Y
The insertion hole into which the upper pipe 12 is inserted can be small, and there is an advantage that the operation time for forming the insertion hole can be reduced. Although the above description has been made with reference to the upper pipe 12, it goes without saying that the same can be applied to the lower pipe 13. 5 and 6 can be applied not only to the above-mentioned gas-insulated transformer but also to a general transformer.
In this case, the iron core fastener is not limited to that of the present invention, and a general iron core fastener may be used.

FIGS. 7 and 8 show another embodiment of the present invention. Since the upper part and the lower part can have the same configuration, only the lower part will be described. However, the flow direction of the insulating gas 4 is reversed between the upper part and the lower part.

FIG. 7 shows the lower pipe 13 and the lower iron core fastener 9 at two ends of one of the lower iron core fasteners 9a and 9b.
An example in which the cooling passages 15a and 15b formed inside the a and 9b are connected, and the other two cooling passages at the other end correspond to the cooling passages 15a and 15b and communicate with the lower space 7 of the tank. It is. The insulating gas 4 sent out by the blower 11 flows into the cooling passages 15a and 15b via the lower pipe 13, and passes through the cooling passages 15a and 15b while the iron core clamps 9a and 9b.
After forced convection cooling of 9b, it flows out into the lower space 7 of the tank.

In this case, since the insulating gas 4 flows from the lower pipe 13 to the two cooling passages 15a and 15b, FIG.
Compared to FIG. 4, the flow rate is higher, the flow rate is larger, and the cooling efficiency is better.

FIG. 7 shows the lower pipe 13 and the lower iron core fasteners 9a, 9 at two central portions of the lower iron core fasteners 9a, 9b.
b, connecting the cooling passages 15a and 15b provided inside,
Cooling paths 15 are provided at the four end portions of the lower iron core fasteners 9a and 9b.
a, 15b and the tank lower space 7 are communicated. The insulating gas 4 flows from the blower 11 via the lower pipe 13 into the cooling passages 15a, 15b from the center, and flows through the cooling passages 15a, 15b, while the iron core clamps 9a,
Heat is taken from 9b and flows out into the lower space 7 of the tank.

Also in the embodiment shown in FIGS. 7 and 8, the core clamps 8a, 8b, 9a and 9b are forcibly convection cooled using the insulating gas 4 for cooling the core 2 and the windings 3. The same operations and effects as described with reference to FIGS.

In the above description, a single-phase center-core type transformer has been described as an example. However, the same applies to transformers and reactors of other structures such as a three-phase tripod, a three-phase pentapod, and a single-phase two-leg. The invention can be applied. Although the gas insulated transformer has been described, the present invention is also effective when applied to a transformer using a liquid insulated cooling medium such as an oil-filled transformer that generates a large amount of heat from the iron core clamp.

[0038]

As described above, according to the present invention,
The upper or lower core fastener for fastening the iron core has a hollow flow path structure, and the flow path is connected to the upper and lower pipes in at least one place, respectively, and communicates with the upper and lower spaces of the tank in at least one place, respectively. In order to cool the iron core and windings, at least a part of the insulating gas circulating in the transformer tank and the cooler by the blower passes through the flow path formed inside the upper or lower iron core clamp. Since it is made to flow, the iron core clamp is forced convection cooled from the inside by the insulating gas. As a result, the cooling performance of the iron core fastener is improved and the rise in temperature can be reduced, so that a highly reliable transformer can be manufactured. In addition, sufficient cooling performance can be obtained even when the capacity and size of the transformer are increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a transformer shown as one embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing the appearance of FIG.

FIG. 3 is a sectional view taken along the line AA in FIG. 1;

FIG. 4 is a sectional view taken along the line BB in FIG. 1;

FIG. 5 is a cross-sectional view of the vicinity of the piping and the iron core fastener of FIG. 1;

FIG. 6 is a cross-sectional view of the vicinity of a pipe and an iron core fastener shown as another embodiment.

FIG. 7 is a cross-sectional view showing the vicinity of a pipe and an iron core fastener shown as another embodiment of the present invention.

FIG. 8 is a cross-sectional view of the vicinity of a pipe and an iron core fastener shown as another embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a conventional transformer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tank, 2 ... Iron core, 3 ... Winding, 4 ... Insulating gas, 5 ...
Partition plate, 6: tank upper space, 7: tank lower space, 8
a, 8b: upper core tightening bracket, 9a, 9b: lower core tightening bracket, 10: cooler, 11: blower, 12: upper pipe, 13: lower pipe, 14a, 14b, 15a, 15b
... cooling passages, 16a, 16b, 17a, 17b ... openings.

Continued on the front page (72) Inventor Yoshihiro Nagao 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside Kokubu Plant, Hitachi, Ltd. (72) Inventor Iwao Umene 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside Hitachi Kokubu Plant (72) Inventor Toshimitsu Obata 1-1-1, Kokubun-cho, Hitachi City, Ibaraki Prefecture Inside Kokubu Plant, Hitachi, Ltd.

Claims (6)

[Claims] 1. An electric appliance in which an end side of an iron core on which a winding is mounted is fastened with a fastener, and the contents of the electric appliance are housed in a tank together with an insulating refrigerant, and a cooler arranged outside the tank and a tank communicate with each other by piping. And an upper space and a lower space defined by providing a partition plate between the windings and the tank, and a cooling path formed inside the fastener. A stationary induction electric device comprising: an insulating refrigerant flowing from a pipe, flowing through the cooling path, and circulating and cooling the cooling device through a winding and an iron core from an entrance provided in a part of the cooling path. 2. The stationary induction device according to claim 1, wherein the cooling passage formed inside the fastener has a shape in which the insulating refrigerant flows linearly from an inlet to an outlet. 3. An insulating refrigerant flowing from the cooling passage opening of the lower fastener through the cooling passage and the inlet / outlet to the windings and the iron core from the lower space through the cooling passage opening of the upper fastener to the upper space from the cooling passage and the inlet / outlet. The static induction device according to claim 1, wherein the static induction device circulates through a pipe and a cooling path via a pipe. 4. An electric appliance in which the side surface of an end of an iron core on which a winding is mounted is fastened by a fastener is housed in a tank together with an insulating refrigerant, and a cooler arranged outside the tank and the tank are communicated by piping. Then, in a device for circulating the insulating refrigerant between the cooler and the tank, a cooling path is formed in the clamp, and the insulating refrigerant from the pipe flows through the clamp and the cooling channel and is provided in a part thereof. A stationary induction electric appliance, which circulates from the inlet / outlet through a winding and an iron core to the cooler, and a cooling passage opening of the upper fastener and a pipe supported by the tank are arranged correspondingly with a gap therebetween. 5. The cooling passage opening of the upper fastener and the piping fixed to the tank are arranged corresponding to each other with a gap therebetween, and the diameter of one of the cooling passage opening and the piping is larger than the other diameter. The static induction device according to claim 4, wherein 6. The cooling passage opening of the upper fastener and the piping supported by the tank are arranged correspondingly with a gap therebetween, and the diameter of one of the cooling passage opening and the piping is larger than the other diameter. 5. The static induction device according to claim 4, wherein the larger portion is wrapped to a smaller diameter through a gap.