JP2013069973A - Stationary induction apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stationary induction apparatus capable of preventing local overheating of a lower fastening metal fitting, without causing an increase in size as a result of using a non-magnetic shield.SOLUTION: A lower fastening metal fitting 5 is shaped into a box having an insulation oil channel 10, which is made of a back surface member 5a, a bottom surface member 5b, a front surface member 5c and an upper surface member 5d. An oil through-hole 12 for insulation oil is formed on the upper surface member 5d of the lower fastening metal fitting 5. A non-magnetic shield 20 arranged between the lower fastening metal fitting 5 and a lower support insulator 8 for winding wires 4a and 4b is attached in a flat plate shape, as with the upper surface member 5d of the lower fastening metal fitting 5. Moreover, part of the flat plate shape of the non-magnetic shield 20 is elongated in a direction intersecting the surface of the upper surface member 5d of the lower fastening metal fitting 5.

Description

  The present invention relates to a static induction electric device such as a transformer or a reactor, and more particularly to a static induction electric device in which a non-magnetic magnetic shield is provided on a lower fastening metal fitting of an iron core.

  Normally, as shown in FIG. 12, a static induction machine, for example, a transformer, has an iron core 2 composed of an iron core leg portion and an iron core yoke portion. An upper fastening metal fitting 3 and a lower fastening metal fitting 5 are provided on both sides of the upper and lower iron core yoke portions. The iron core shape is arranged and fixed by tightening. A high-voltage side winding 4a and a low-voltage side winding 4b that are concentrically arranged and separated by an insulating cylinder 7 are wound around the iron core leg of the iron core 2, and are supported above and below each of the windings 4a and 4b. The upper support insulator 6 and the lower support insulator 8 are disposed, and the windings 4a and 4b are supported between the upper clamp 3 and the lower clamp 5 to constitute a transformer body.

  The transformer main body is disposed in the tank 1 and filled with the insulating oil 9, and the lower clamp 5 of the iron core 2 has an insulating oil passage 10 formed therein, and the insulating oil 9 is used as the oil. It is introduced into the windings 4a and 4b from the guide hole 11 and cooled.

  The upper clamp 3 and the lower clamp 5 are made of a metal material such as steel or stainless steel having sufficient strength. And each clamp | tightening metal fittings 3 and 5 are arrange | positioned in the both ends of the high voltage | pressure side coil | winding 4a and the low voltage | pressure side coil | winding 4b, Therefore An eddy current flows with the leakage magnetic flux from a coil | winding, loss increases, May cause. When transformers are downsized as recently, leakage flux tends to increase, so eddy current loss also increases, and local overheating may occur.

  For this reason, conventionally, as described in Patent Documents 1 and 2, for example, magnetic shields such as silicon steel plates are arranged as magnetic shields at the upper and lower ends of the windings 4a and 4b. This magnetic shield absorbs leakage magnetic flux from the winding to reduce local eddy current loss concentration and temperature rise.

  In addition, as another countermeasure against leakage magnetic flux in the past, as described in Patent Documents 3 and 4, for example, a non-magnetic shield such as a copper plate shield is attached to the lower clamp 5. In general, as shown in FIGS. 13B and 14, the lower clamp 5 is composed of a rear surface member 5a located on the lower yoke portion side and a bottom surface member 5b on the bottom surface side of the tank 1 fixed to the rear surface member 5a. And a front surface member 5c fixed to the bottom surface member 5b, a back surface member 5a, and a top surface member 5d fixed to the front surface member 5c. In addition, the upper surface member 5d of the lower clamp 5 is formed with an oil passage hole 12 in a portion facing the oil guide hole 11, and a portion indicated by a broken line not facing the oil guide hole 11 is removed to form the back surface member 5a. The surface of the bottom member 5 b forms a complete opening 5 e that opens into the tank 1.

  For this reason, the lower fastening metal fitting 5 configured as described above is conventionally made of a copper plate having a width W made in accordance with the shape surface of the upper surface member 5d having the oil passage holes 12 as shown in FIG. Such a flat nonmagnetic shield 20 is attached. With this nonmagnetic shield 20, the leakage flux is reduced by the eddy current flowing back through the nonmagnetic shield 20 and the bottom clamp bottom portion 53, etc., thereby reducing the eddy current loss that occurs intensively. It has been broken.

JP 58-139415 A JP-A-4-65809 JP 2008-41929 A JP 2009-76534 A

The structure in which the magnetic shield of the magnetic material described in Patent Documents 1 and 2 described above is effective in preventing local eddy current loss concentration and temperature rise. However, since it is necessary to provide the magnetic shield with a certain volume in order to recirculate the leakage magnetic flux, the height of the structure at the upper and lower ends of the winding is larger than when the magnetic shield is not provided. As a result, there is a problem that the tank becomes large.

  On the other hand, when the non-magnetic shield 20 such as the copper plate described in Patent Documents 3 and 4 is arranged, the eddy current flowing through the non-magnetic shield 20 causes a magnetic flux to be partially applied to the lower fastening bracket. Avoid concentration and prevent local temperature rise. However, a flat nonmagnetic shield 20 made in accordance with the shape of the oil passage hole 5e and the complete opening 5f is attached to the upper surface member 5d of the lower clamp 5 so that one nonmagnetic shield is provided. Since the constricted portion is formed in the portion, eddy currents are concentrated in the constricted portion, and eddy current loss is concentrated, which may cause a problem that a local temperature rise occurs.

  An object of the present invention is to provide a static induction electric appliance capable of preventing local overheating of a lower clamp fitting without using a nonmagnetic shield to increase the size.

  The present invention is wound around an iron core consisting of an iron core leg portion and upper and lower iron core yoke portions, an upper fastening metal fitting and a lower fastening metal fitting arranged in each iron iron core yoke portion, and an iron core leg portion of the iron core. A high-voltage side winding, a low-voltage side winding, a supporting insulator disposed between each of the windings, the upper fastening bracket and the lower fastening bracket, and a tank; The member, the bottom member, the front member, and the top member constitute a box shape having an insulating oil flow path, and an oil passage hole is formed in the top member between the lower fastening bracket and the lower support insulator. The non-magnetic shield is attached to the non-magnetic shield in the same flat plate shape as the upper member of the lower clamp, and a part of the flat plate is attached to the upper surface of the lower clamp. It is characterized by being configured to extend in the direction intersecting the member surface.

  Preferably, the non-magnetic shield is configured such that a thickness of a portion to be extended in a direction crossing the upper surface member is different from a thickness of a portion to be attached between the lower fastening bracket and the lower support insulator. It is said.

  Further preferably, the non-magnetic shield is characterized in that a portion extending in a direction intersecting with the upper surface member is projected into the insulating oil flow path of the lower fastening bracket.

  When a nonmagnetic shield placed between the lower clamp and the lower support insulator is disposed as in the static induction appliance of the present invention, the nonmagnetic shield is connected to the upper member of the lower clamp. By mounting the same flat plate and extending a part of the flat plate in a direction intersecting the upper surface member surface of the lower clamp, the effective cross-sectional area in the nonmagnetic shield is increased. Since the eddy current density can be reduced, the eddy current loss generated by avoiding a local temperature rise can be greatly reduced as compared with the conventional case. Further, the heat generated in the nonmagnetic shield can be efficiently cooled by being conducted through the nonmagnetic shield with good thermal conductivity and contacting the insulating oil over a wide area. Furthermore, since a part of the non-magnetic shield is extended in a direction intersecting the upper surface member surface of the lower clamp, the oil passage hole formed in the upper member plate of the lower clamp is not blocked. There is no hindrance to the cooling of the winding side, and the static induction device is not increased in size due to the non-magnetic shield.

It is a schematic longitudinal cross-sectional view which shows one Example of the transformer to which this invention is applied. It is a perspective view which shows the detail of the nonmagnetic material shield used for the transformer of FIG. It is a longitudinal cross-sectional view which shows the attachment state of the nonmagnetic body shield in the lower clamp | tightening metal fitting of the transformer of FIG. FIG. 4 is a development view of the nonmagnetic shield of FIG. 3. It is a longitudinal cross-sectional view which shows the attachment state of the nonmagnetic body shield which is a modification of FIG. It is a longitudinal cross-sectional view which shows the attachment state of the nonmagnetic body shield in the lower clamp | tightening metal fitting which is another Example of this invention. It is a longitudinal cross-sectional view which shows the attachment state of the nonmagnetic body shield which is a modification of FIG. It is a longitudinal cross-sectional view which shows the attachment state of the nonmagnetic body shield in the lower clamp | tightening metal fitting which is another Example of this invention. It is an eddy current density distribution map of a nonmagnetic shield. It is an eddy current loss distribution map of a nonmagnetic shield. It is explanatory drawing which represented the maximum temperature of the nonmagnetic body shield according to each structure with the raise value from insulating oil temperature. It is a schematic longitudinal cross-sectional view of the conventional transformer. (A) is a perspective view which shows the nonmagnetic body shield applied to FIG. 12, (b) is a perspective view which shows a lower clamp | tightening metal fitting. It is a longitudinal cross-sectional view which shows the attachment state of the nonmagnetic body shield in the lower clamp | tightening metal fitting applied to FIG.

  Hereinafter, the static induction appliance of the present invention shown in FIG. 1 to FIG. 11 will be described in order using each embodiment in which the same reference numerals are given to the same parts as those in the past when applied to a transformer.

  As shown in FIG. 1, the transformer to which the present invention is applied is configured in the same manner as in the prior art, and a nonmagnetic shield 20 is provided between the lower support insulator 8 and the lower clamp 5. . In the embodiment of the present invention shown in FIGS. 1 to 11, the nonmagnetic material shield 20 is shown as an example using a copper plate shield.

  As in the conventional case, the lower clamp 5 includes a back surface member 5a on the iron core 2 side, a bottom surface member 5b on the bottom surface side of the container 1, a front surface member 5c on the side surface side of the container 1, and a winding. 4a and 4b are formed in a box shape having an insulating oil flow path 10 by an upper surface member 5d located at the lower part. An oil passage hole 12 is formed in the upper surface member 5d of the lower clamp 5 so that the insulating oil 9 is guided to the lower portions of the windings 4a and 4b through the oil guide holes 11 of the lower support insulator 8. .

  On the upper surface member 5d of the lower clamp 5 is attached a non-magnetic shield 20 which is a flat plate having the same shape as the surface of the upper surface member 5d. The nonmagnetic shield 20 has a special shape in which the dimensions of the portion corresponding to the oil passage hole 12 and the portion corresponding to the complete opening from which the surface of the upper surface member 5d is removed are widened. That is, the nonmagnetic shield 20 has a width that is located on the upper surface member 5d by making a notch 21 as shown in FIG. 4 in a portion corresponding to the oil passage hole 12 formed in a wide width and a portion corresponding to the complete opening. W1 shield main plate material 20a, width W2 shield sub-plate material 20b, and width W3 shield sub-plate material 20c are formed and bendable.

  The nonmagnetic shield 20 formed in this way corresponds to the oil passage hole 12 formed wide after being arranged on the surface of the upper surface member 5d of the lower clamp as shown in FIGS. In the portion corresponding to the portion and the complete opening, the shield sub-plate material 20b is bent and extended toward the oil passage hole 12 and the complete opening that are in the direction intersecting the surface of the upper surface member 5d. In addition, in the example of FIG. 3, the shield sub-plate material 20 c is further bent and attached so as to cover the upper surface member 5 d surface in the insulating oil flow path 10.

  As described above, the portion of the upper surface member 5d having the oil passage holes 12 shown in FIG. 3 includes the non-magnetic shield 20 composed of the width W1 of the shield main plate 20a, the width W2 of the shield subplate 20b, and the width W3 of the shield subplate 20c. Is attached. Therefore, when the mounting structure of the nonmagnetic shield 20 shown in FIG. 3 is examined with the eddy current density distribution shown in FIG. 5 and the eddy current loss distribution shown in FIG. 6, the following is obtained. The characteristic of the structure for attaching the non-magnetic shield 20 of FIG. 3 is indicated by a distribution line labeled “thin side surface thickness” connecting the white circles shown in FIGS. 9 and 10.

  In the case of the conventional nonmagnetic shield 20 shown in FIG. 14, eddy currents and losses are concentrated on the origin side up to the width W indicated by the alternate long and short dash line. On the other hand, the attachment structure of the non-magnetic shield 20 of FIG. 3 of the present invention gradually decreases as it moves away from the origin on the iron core side, and the shield with the width W2 as compared with the region of the shield main plate 20a with the width W1. If it becomes the area | region of the shield subplate material 20c of the subplate material 20b and the width W3, it will fall significantly. Therefore, in the case of the nonmagnetic shield 20 mounting structure shown in FIG. 3 of the present invention, both eddy current and eddy current loss are distributed over a wide range, and the peak values of eddy current density and eddy current loss are Decrease significantly.

  In addition, the nonmagnetic shield 20 of the present invention can reduce the maximum temperature rise as compared with the conventional mounting structure. That is, as shown by the maximum temperature rise value from the insulation oil temperature of the non-magnetic shield in each structure of FIG. 11, the non-temperature shown in FIG. 3 of the present invention is higher than the maximum temperature of the conventional shield structure A. The maximum temperature rise of the shield structure B of the magnetic shield 20 is reduced to about 58%.

  The attachment structure of the nonmagnetic shield 20 shown in FIG. 3 can be attached in the modified structure shown in FIG. In this structure, the shield sub-plate material 20c of the non-magnetic shield 20 is lengthened, bent to the tip L shape, and disposed on the inner surface of the back surface member 5a. In this way, the area of the nonmagnetic shield 20 in contact with the insulating oil 9 can be increased. For this reason, even when the eddy current loss on the upper surface of the nonmagnetic shield 20 is large, most of the heat loss can be transferred by heat conduction to dissipate heat from a wide area, thereby enabling efficient cooling. In the attachment structure of the nonmagnetic shield 20 in FIG. 5, as shown in the shield structure C in FIG. 11, the maximum temperature rise of the conventional shield structure A is reduced to about 58%.

  If the transformer is configured as in the present invention, the increase in temperature of the constricted portion of the nonmagnetic shield 20 can be reduced without increasing the size of the container 1 and the iron core 2, and the lower tightening is achieved by the effect of the nonmagnetic shield 20. The local temperature rise in the metal fitting 5 can be prevented.

  Another mounting structure of the nonmagnetic shield 20 is shown in FIG. In this example, the non-magnetic shield 20 is divided into a shield main plate material 20a, a shield sub plate material 20b, and a shield sub plate material 20c. The shield main plate member 20a is arranged in an L-shaped manner at the upper surface member 5d portion of the lower clamp 5 and is attached to the shield main plate member 20a so as to partially overlap the shield main plate member 20a to increase the thickness. The plate member 20c is bent and attached to the surface of the upper surface member 5d on the insulating oil flow path 10 side. The shield main plate member 20a, the shield sub plate member 20b1, and the shield sub plate member 20c1 that are divided into two can be used even if they have different thicknesses or combinations of different thicknesses.

  In the structure for attaching the nonmagnetic shield 20 shown in FIG. 6, the shield main plate material 20a and the shield sub plate material 20b1 divided into two parts are arranged so as to partially overlap each other. There are two effects described.

  First, by dispersing the eddy current flowing through the nonmagnetic shield 20 in a wider range, the peak of eddy current and eddy current loss can be lowered. This is because the characteristic of the structure for attaching the nonmagnetic shield 20 in FIG. 6 is an area having a width W2 as indicated by a distribution line labeled “large side face” connecting the white corners shown in FIGS. Thus, it is clear from the fact that the decrease is mitigated rather than the one in which the eddy current density and loss suddenly decrease at “thin side surface thickness” in FIG. Further, since heat conduction is promoted from the shield main plate material 20a of the nonmagnetic shield 20 to the shield sub plate material 20b1 and the shield sub plate material 20c1, further efficient cooling can be performed. As a result of the above two effects, when the non-magnetic shield 20 is attached as shown in FIG. 6, as shown by the shield structure D in FIG. 11, the maximum temperature rise of the conventional shield structure A is reduced to about 52%. Is done. Therefore, also in this example, the same effect as in the first embodiment can be achieved.

  The nonmagnetic shield 20 can be attached with the structure shown in FIG. 7 modified from FIG. The nonmagnetic shield 20 mounting structure is a combination of the shield main plate material 20a, the shield sub-plate material 20b1, and the shield sub-plate material 20c1, which are divided into two as in the example of FIG. Similarly, the front end portion of the shield sub-plate material 20c1 is lengthened, bent into the front end portion L shape, and disposed on the inner surface of the back surface member 5a.

  In the case of FIG. 7 as well, since the area of the nonmagnetic shield 20 in contact with the insulating oil 9 can be increased, similarly efficient cooling is possible. In the mounting structure of the nonmagnetic shield 20 of this example, as shown by the shield structure E in FIG. 11, compared with the maximum temperature rise of the conventional shield structure A, it is reduced to about 47%.

  Another example of the attachment structure of the nonmagnetic shield 20 is shown in FIG. The non-magnetic shield 20 is configured so that the shield sub-plate material 20b and the shield sub-plate material 20c are perpendicular to the upper surface member 5d surface from the shield main plate material 20a disposed on the upper surface member 5d surface of the lower clamp 5. The shield sub-plate material 20c is bent and protruded into the insulating oil flow path 10.

  If it does in this way, since both surfaces of the shield sub-plate material 20c of the nonmagnetic shield 20 become the heat radiating surfaces in contact with the insulating oil 9, the nonmagnetic shield can be efficiently cooled with a simple structure. As a result, the attachment structure of the nonmagnetic shield 20 in FIG. 8 is reduced to about 47% as compared with the maximum temperature rise of the conventional shield structure A as shown by the shield structure F in FIG. For this reason, also in this example, the same effect as Example 1 can be achieved.

DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Iron core, 3 ... Upper clamping metal fitting, 4a ... High voltage side winding, 4b ... Low voltage side winding, 5 ... Lower clamping metal fitting, 5a ... Back surface member, 5b ... Bottom member, 5c ... Front Members, 5d ... upper surface member, 8 ... lower support insulator, 9 ... insulating oil, 10 ... insulating oil flow path, 12 ... oil passage hole, 20 ... non-magnetic shield, 20a ... shield main plate material, 20b, 20c ... shield Sub board material.

Claims (3)

  An iron core composed of an iron core leg part and upper and lower iron core yoke parts, upper and lower fastening metal parts arranged in each iron core yoke part, and a high-voltage side winding wound around the iron core leg part of the iron core And a low-voltage side winding, a support insulator disposed between each of the windings, the upper fastening bracket and the lower fastening bracket, and a tank, and the lower fastening bracket includes a back member and a bottom member. And a front member and an upper surface member to form a box shape having an insulating oil flow path, an oil passage hole is formed in the upper surface member, and a non-magnetic material is provided between the lower clamp fitting and the lower support insulator. In the static induction appliance in which the shield is disposed, the nonmagnetic shield is attached in the same flat plate shape as the upper surface member of the lower clamp, and a part of the flat plate intersects with the upper member surface of the lower clamp. A static induction machine characterized by being configured to extend in the direction of movement.   2. The non-magnetic shield according to claim 1, wherein a thickness of a portion to be extended in a direction intersecting with the upper surface member is made different from a thickness of a portion attached between the lower clamp fitting and the lower support insulator. Static induction electric machine characterized by.   4. The static induction according to claim 2, wherein the non-magnetic shield is configured such that a portion that extends in a direction intersecting the upper surface member protrudes into the insulating oil flow path of the lower fastening bracket. Electricity.

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