JPH0341451Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a separate type evaporative cooling induction electric appliance in which a non-condensable insulating gas and a condensable cooling medium are separated by a sealed insulating container.

[Prior art and its problems]

In recent years, there has been an increasing demand for high-voltage, large-capacity transformers, reactors, and other induction electrical appliances to be non-combustible and flame-retardant, mainly from the standpoint of disaster prevention. fluorocarbon, having
Evaporative cooling induction electric appliances that use condensate such as chlorofluorocarbon as a cooling medium and insulating gas such as SF ₆ gas as an insulating medium are attracting attention, and compared to insulating oil, they use much less expensive cooling medium and have better cooling performance. There is a need for induction electric appliances that are both superior and capable of higher voltage.

FIG. 3 is a schematic side sectional view showing an example of a conventional separate type evaporative cooling induction electric appliance. In the figure,
A disk winding 3 is housed in a tank 1 containing an insulating gas 9, and is composed of a layered assembly of a flat ring-shaped section coil 4 wound around an iron core 2 and an inter-section duct 5. It is housed in a sealed insulated container 6 formed to hold an axial passage 7 for the condensed liquid 10 of the cooling medium on the side, and the sealed insulated container 6 has a pair of upper and lower circulation passages 8A,
8B, a separate type evaporative cooling induction electric appliance is constructed in which a closed circulation system for condensate and a space filled with insulating gas 9 are partitioned by communicating with a heat exchanger 12 via a circulation pump 11. .

In the induction electric machine configured as described above, sensible heat cooling is performed by the condensate sent to the winding 3 by the circulation pump 11 when the induction electric machine is under a light load, and when the induction electric machine is under a heavy load, the condensate is sent to the winding 3. Evaporative cooling is performed by boiling the condensate in contact with the surface, and the electric field is locally concentrated in the vicinity of the winding 3, where there are many high electric field areas, due to the condensate having high withstand voltage strength. Although the withstand voltage strength is relatively low in the part with a small part, the electrical insulation of the winding 3 is reasonably maintained by the lightweight and inexpensive insulating gas 9, so the amount of expensive condensate used is small. , and is configured to provide an induction electric appliance with excellent cooling performance and withstand voltage performance.

FIG. 4 is a cross-sectional view of the main part showing the evaporative cooling state of the induction electric appliance shown in FIG. The steam bubbles 100 thus generated gather in the axial passage 7 along the lower surface of the section coil 4 and are carried away toward the heat exchanger 12 by the condensate 10 flowing through the axial passage 7. The further downstream the section coil is located, the higher the density of the bubbles passing laterally, and the bubbles coalesce and become larger, resulting in the situation shown in the figure. However, the electric field is concentrated at the corner of the section coil 4 based on the ground potential of the winding and the potential difference between the section coils, and a high electric field portion 21 exists as shown surrounded by a broken line in the figure. Not only is the bubble 100 exposed to a high electric field, but the bubble 100 is also
The electric field in the 0 becomes several times higher, spark discharge occurs in the bubble 100, and there is a danger that this will trigger a short circuit accident between the section coils, and the voltage of the induction electric device will be increased. This has become a serious weakness in the process.

[Purpose of invention]

This idea was created in view of the above-mentioned situation.
The purpose of the present invention is to provide a highly reliable evaporative cooling induction electric appliance in which the influence of vapor bubbles on the withstand voltage performance of the windings is eliminated.

[Key points of the idea]

The present invention is a thin insulator that protrudes into the axial passage from the lower surface of the inner and outer circumferential sides of each section coil of a disc winding consisting of a plurality of section coils, and the protruding part is curved toward the downstream side of the condensate. A steam bubble guiding section made of a plate is provided to guide the steam bubbles generated on the surface of the section coil to the side opposite to the winding of the axial passage, and a plate is attached to the side facing the axial passage of the sealed insulating container. By providing a vapor bubble trapping layer made of a low-density felt-like insulating material, vapor bubbles guided toward the trapping layer by the guide section are temporarily trapped by the fluff on the surface of the trapping layer. After that, the vapor bubbles are washed away by the flow of condensate flowing along the surface of the trapping layer and discharged outside the sealed insulating container, thereby reducing the density of vapor bubbles in the high electric field area at the corner of the section coil. This is what I did.

[Example of idea]

The present invention will be explained below based on examples.

FIG. 1 is a side sectional view of a main part showing an embodiment of the present invention. In the figure, a plurality of flat ring-shaped section coils 4 and an inter-section duct 5 whose spacing is maintained by an inter-section spacer (not shown)
A disc winding 3 consisting of the following is housed in a sealed insulating container 5 formed to hold an axial passage 7, which serves as a passage for the condensate 10, on its inner and outer circumferential sides. As shown, it is stored in a tank 1 that contains an insulating gas 9, and a circulation passage 8.
A, 8B, a circulation pump 11, and a heat exchanger 12. 31 is a steam bubble guide made of a thin insulating plate such as pressboard or aromatic polyamide paper, and is attached to the lower surface of the coil along the inner and outer circumferential sides of each section coil, or with an inter-section spacer (not shown). The part that is sandwiched between the coil and the part that protrudes into the axial passage 7 contains the condensate 10.
By being curved toward the downstream side of the condensate 10, the flow of the condensate 10 is not obstructed. Reference numeral 32 denotes a vapor bubble trapping layer made of nonwoven fabric or low-density felt, and is applied to cover the side of the sealed insulating container 5 facing the axial passage 7.

FIG. 2 is a perspective view showing the guide part 3.
The protrusions 31A into the axial passage 7 of No. 1 are inserted in the axial direction at intervals in the circumferential direction in order to maintain the interval between the section coil 4 and the sealed insulating container 5, that is, the gap length of the axial passage. axial spacer 1
7, and the length and curvature of the protrusion are determined so as not to disturb the flow of condensate, but to accelerate the flow rate to some extent.

In the induction electric device configured as described above, air bubbles generated by vaporization of the condensate 10 on the surface of the section coil 4 are caused by a flow based on the convection of the condensate in the inter-section duct 5 and the guide portion 3.
1, each section coil is guided to the trapping layer side of the axial passage 7, and once trapped between the fibers fluffed on the surface of the trapping layer, the guide section intervenes to accelerate the fibers. The condensate 10 is washed away by the flow of the condensate 10, and is discharged out of the axial passage without approaching the high electric field portion 21 at the corner of the section coil 4. Therefore, it is possible to prevent an increase in bubble density and an increase in the size of bubbles in the high electric field section 21 of the section coil located downstream of the flow of the condensate 10, and therefore the winding 3 caused by steam bubbles can be prevented. It is possible to prevent the deterioration of the withstand voltage performance.

Note that the guide portion 31 may be formed by gluing a strip-shaped member cut to the width of the protruding portion 31A to the lower surface of the section coil 4, or a ring-shaped member having a notch in a portion corresponding to the axial spacer 17 may be bonded to the lower surface of the section coil 4. It may also be configured to be sandwiched between the front coil and the inter-section spacer. Further, the trapping layer 32 may be formed by covering the entire surface with a sheet-like material, or may be structured so that a tape-like material is applied thereon.

[Effect of idea]

As described above, the present invention includes a steam bubble guide section that is formed to protrude into the axial passage of the condensate from the lower surface of the inner and outer circumferential sides of each section coil and curve toward the downstream side of the flow. , and a vapor bubble trapping layer made of a felt-like insulating material adhered to the opposite wall of the insulating container. As a result, the vapor bubbles of the condensate generated on the surface of each section coil are guided toward the trapping layer side by the guide section of each section coil, and are once trapped by the fluffed portion of the trapping layer, and then are trapped by the guide section. Due to the protrusion, the condensate flow accelerates and is washed away and discharged to the outside of the sealed insulated container. The problem of high density is eliminated, and the deterioration in voltage resistance performance caused by vapor bubbles is prevented, thereby making it possible to provide an evaporatively cooled induction electric appliance with excellent insulation performance.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of the main part showing an embodiment of the present invention, Fig. 2 is a perspective view showing the structure of the guide section, Fig. 3 is a side sectional view showing an example of a conventional evaporative cooling induction electric appliance, FIG. 4 is a side sectional view of the main part showing the evaporative cooling state. 1...tank, 2...iron core, 3...disc winding,
4...Section coil, 5...Duct between sections, 6...Hermetically sealed insulating container, 7...Axial passage,
8A, 8B...Circulation passage, 9...Insulating gas, 10
... Condensate, 12 ... Heat exchanger, 21 ... High electric field section, 31 ... Guide section, 31A ... Projection, 32 ...
...Capture layer, 100...Steam bubbles.

Claims (1)

[Scope of utility model registration request] A disk winding wound around an iron core housed in a tank with an external heat exchanger and an insulating gas inside, and an axial passage for cooling medium on the inner and outer circumferential surfaces of this disk winding. A sealed insulating container that houses the disc winding and communicates with the heat exchanger via a circulation passage,
a steam bubble guide portion made of an insulating material that protrudes into the axial passage from the lower surface side of each of the plurality of flat ring-shaped section coils of the disc winding, and has a protruding portion curved toward the downstream side of the flow; An evaporative cooling induction electric appliance comprising: a vapor bubble trapping layer made of a felt-like insulating material and adhered to the surface of the sealed insulating container facing the axial passage.