Stationary induction electric device

The invention is directed to a stationary induction electric device that can reduce loss. To this end, the stationary induction electric device is provided with a first iron core block erected and formed in an annular shape, a second iron core block configured to surround the outer periphery of the first iron core block, a winding wound around the first and the second iron core blocks, a first support plate supporting the upper portion of the first iron core block from below, and a second support plate supporting the upper portion of the second iron core block from below, and a curvature radius of a curved portion appearing on the outer periphery of the lower portion of the second iron core block is made larger than a curvature radius of a curved portion appearing on the outer periphery of the upper portion of the second iron core block.

TECHNICAL FIELD

The present invention relates to a stationary induction electric device.

BACKGROUND ART

A stationary induction electric device such as a transformer and a reactor has an iron core composed with a magnetic body. A wound iron core using an amorphous magnetic ribbon has an advantage that it has lower loss than an iron core in which electromagnetic steel sheets are laminated. However, among the wound iron cores using amorphous magnetic ribbons, especially large-sized wound iron cores are prone to buckling due to their own weights and easily deform. When the iron core deforms, there arises a problem that characteristics of the magnetic body are changed and the loss is increased. For this reason, support members are frequently used in this kind of stationary induction electric device to suppress the deformation of the iron core. For example, the following Patent Literature 1 describes that “ . . . the iron core support member100is formed by integrating a side surface support member which supports a side surface of the amorphous iron core110and a corner portion support member101which supports a corner portion of the iron core; the corner portion support member101has a shape following the curve of the corner portion of the iron core, a plurality of the corner portion support members are arranged at a predetermined interval, and the amorphous iron core and the side surface support member are inserted into a coil” (see Abstract).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In the structure disclosed in the Patent Literature 1, the deformation of the iron core can be suppressed to some extent. However, there is still room for further improvement. In addition, not only the weight of the iron core itself, but also the stress in a laminating direction of the iron core may become a factor of deforming the iron core and increasing the loss. However, in the Patent Literature 1, no particular consideration is given to the stress in the laminating direction of the iron core.

The present invention has been made in view of the above circumstances, and an object is to provide a stationary induction electric device which can reduce loss.

Solution to Problem

In order to solve the aforementioned problem, the stationary induction electric device of the invention comprises

a first iron core block erected and formed in an annular shape,

a second iron core block configured to surround the outer periphery of the first iron core block,

a winding wound around the first and the second iron core blocks,

a first support plate supporting the upper portion of the first iron core block from below, and

a second support plate supporting the upper portion of the second iron core block from below,

wherein a curvature radius of a curved portion appearing on the outer periphery of the lower portion of the second iron core block is larger than a curvature radius of a curved portion appearing on the outer periphery of the upper portion of the second iron core block.

Advantageous Effects of Invention

According to the stationary induction electric device of the invention, the loss can be suppressed.

DESCRIPTION OF EMBODIMENTS

Comparative Example

Before describing the embodiments of the invention, the configuration of an iron core according to a comparative example will be described.FIG. 1is a front view of an iron core2according to the comparative example.

InFIG. 1, the iron core2has nested iron core blocks2A,2B and2C. The iron core blocks2A,2B and2C are respectively formed in a substantially rectangular frame shape with rounded corners. These iron core blocks2A,2B and2C are laminated while curving an amorphous magnetic ribbon, and the direction from the inner side to the outer side is the laminating direction.

A support plate portion3supports the iron core2and includes support plates3A,3B and3C which are in a substantially rectangular plate shape. These support plates3A,3B and3C are disposed so as to adhere to the inner surfaces of upper portion yoke portions (upper side portions) of the iron core blocks2A,2B and2C respectively, and are supported by support beams which are not shown in the drawing. Each of the iron core blocks2A,2B and2C has a vertically symmetrical shape, and thus the curvature radiuses of the corner portions of these iron core blocks become larger in outer iron core blocks. The curvatures of both end portions of the support plates3A,3B and3C also become larger in outer iron core blocks.

In the present comparative example, the iron core2is dispersed in a plurality of iron core blocks2A,2B and2C. As a result, self-weight and stress in the laminating direction can be dispersed, and thus loss due to deformation of the iron core2can be reduced. However, in the comparative example, there is much dead space on the upper portion of the iron core2. In this case, there is a problem that iron loss increases as the length of magnetic path increases, which offsets the loss reduction effect by suppressing the deformation of the iron core2. In addition, there is also a problem that the size of a stationary induction electric device to which the iron core2is applied, and the size of a tank (not shown in the drawing) storing the same are increased. Therefore, the embodiments described below are intended to alleviate the aforementioned problems in the comparative example.

First Embodiment

Next, the configuration of a stationary induction electric device T1according to a first embodiment of the invention will be described with reference toFIG. 2toFIG. 4. Here,FIG. 2is a partially cutaway front view of the stationary induction electric device T1, andFIG. 3is an enlarged view of a main portion Q thereof. Further,FIG. 4is a front view of an iron core22.

InFIG. 2, the stationary induction electric device T1is a transformer with a single phase tripod structure, and includes two iron cores12and22which are arranged adjacently, and a winding11wound around the iron cores12and22. Here, the winding11includes a primary winding11A wound in inner side and a secondary winding11B wound in outer side. A lower portion fixing member15is fixed to the installation place of the stationary induction electric device T1.

Although only one support post16is shown inFIG. 2, the support post16is arranged at four corners of the lower portion fixing member15and altogether four support posts16are arranged. Each support post16is erected along the vertical direction, and the lower end portion thereof is fixed to the lower portion fixing member15. An upper portion fixing member is fixed to the support post16while bridging the upper portions of the support posts16adjacent to each other in the left-right direction. Further, the upper portion fixing member14is also provided (not shown in the drawing) so as to bridge two support posts16on the rear surface of the stationary induction electric device T1. Support plate portions13and23support the iron cores12and22while being fixed to the upper portion fixing members14on the front surface and the rear surface. Fixation between the members may be realized by any method, such as bolt fastening, screw fastening, fastening with a tape or a string, and bonding with a resin.

The right side part ofFIG. 2shows a state in which a part of the winding11, the upper portion fixing member14, the lower portion fixing member15, and the support post16are cut away. The iron core22includes nested iron core blocks22A (first iron core block),22B (second iron core block), and22C (third iron core block). These iron core blocks22A,22B and22C are wound iron cores in which amorphous magnetic ribbons are curved into annular shapes and are laminated, and the depth direction of the paper sheet is the width direction of the magnetic ribbon. Each of the iron core blocks22A,22B and22C is formed in a substantially rectangular frame shape with rounded corners and has a bilaterally symmetrical shape. However, the curvature radius of the lower side corner is larger than the curvature radius of the upper side curved portion. The details will be described later. The iron core12includes iron core blocks12A (first iron core block),12B (second iron core block), and12C (third iron core block), and is configured in the same manner as the iron core22. In the iron cores12and22, a portion extending along the vertical direction is referred to as an “iron leg”. The primary winding11A is wound so as to surround a right iron core leg of the iron core12and a left iron core leg of the iron core22, and the secondary winding11B is wound so as to further surround the primary winding11A.

The upper portion fixing member14includes plate-shaped fixing members14A,14B and14C, and these fixing members14A,14B and14C are arranged in parallel along the horizontal direction and are fixed to the support posts16while bridging the left and right support posts16(the right side is not shown in the drawing). Further, as described above, the upper portion fixing member14which is not shown in the drawing is also provided on the rear surface of the stationary induction electric device T1, and the upper portion fixing member14on the rear surface also includes the fixing members14A,14B and14C which are the same as those on the front surface.

The support plate portion13includes support plates13A (first support plate),13B (second support plate), and13C (third support plate) which are in a substantially rectangular flat plate shape. These support plates13A,13B and13C are arranged so as to bridge the fixing members14A,14B and14C on the front surface and on the rear surface which are not shown in the drawing, and are fixed to these fixing members14A,14B and14C. The support plates13A,13B and13C support the iron core blocks12A,12B and12C by adhering their upper surfaces to the inner surfaces of the upper portion yoke portions of the iron core blocks12A,12B and12C. The support plate portion23includes support plates23A,23B and23C configured in the same manner as the support plate portion13.

The support plates23A,23B and23C are arranged so as to bridge the fixing members14A,14B and14C on the front surface and on the rear surface which are not shown, and support the iron core blocks22A,22B and22C. That is, the support plates13A and23A are fixed to the upper surface of the fixing member14A, the support plates13B and23B are fixed to the upper surface of the fixing member14B, and the support plates13C and23C are fixed to the upper surface of the fixing member14C. In addition, the winding11is fixed to the upper portion fixing member14and the lower portion fixing member15.

Next, the main portion Q inFIG. 2will be described in details. InFIG. 3, the iron core blocks22A,22B and22C have a structure in which the horizontal upper portion yoke portion is curved at the end portion and extends to a vertical iron core leg, and the curvature radiuses of the curves in inner peripheries are respectively referred to as R2A, R2Band R2C. The iron core legs of the iron core blocks22A,22B and22C are arranged with gaps GABand GBC. The support plates23A,23B and23C are in a substantially flat plate shape with plate thicknesses of T3A, T3Band T3Crespectively, and are respectively in contact with the inner sides of the upper portion yoke portions of the iron core blocks22A,22B and22C to support these upper portion yoke portions from below. The upper surface end portions of the support plates23A,23B and23C are chamfered at curvature radiuses R3A, R3Band R3Calong the inner surfaces of the curved portions of the iron core blocks22A,22B and22C respectively.

Here, the relationship among the above-mentioned dimensions will be described. First, the value of the curvature radius R2Aof the iron core block22A is preferably made as small as possible (for example, the minimum value) within an allowable range determined by the magnetic characteristics and the mechanical strength of the magnetic ribbon. Moreover, the gaps GABand GBCare provided for reasons of workability and manufacturing tolerance, and are preferably to be set to about several mm. However, the iron core blocks22A,22B and22C may be adhered to each other depending on conditions, and thus it is preferable to set within the ranges 0≤GAB≤10 mm and 0≤GBC≤mm. Further, as to the relationship of the curvature radiuses of the support plates23A,23B,23C and the iron core blocks22A,22B,22C, it is preferable to set R2A=R3A, R2B=R3B, and R2C=R3C. In other words, the left and right ends of the support plates23A,23B and23C are brought into contact with both ends of the upper portion yokes of the iron core blocks22A,22B and22C which they support respectively, and are preferable to be chamfered with the innermost curvature radius.

In addition, regarding the relationship among the curvature radiuses R2A, R2Band R2C, it is preferable that R2A≤R2Band R2A≤R2C. As to the relationship between the curvature radiuses R2A, R2B, R2Cand the plate thicknesses T3A, T3B, T3C, it is preferable that R2A≤T3A, R2B≤T3B, and R2C≤T3C. The plate thicknesses T3A, T3B, and T3Care preferable to be sufficient to support the iron core blocks22A,22B and22C respectively, and it is preferable to set the gaps that GAB≤T3B, and GBC≤T3C.

Next, the curvature radiuses of the curved portions on the outer periphery of the iron core blocks22A,22B and22C will be described with reference toFIG. 4. A center line in the vertical direction of the iron core2is referred to as L, the upper side from the center line L is referred to as “upper portion”, and the lower side from the center line L is referred to as “lower portion”. The iron core block22A includes a pair of vertical iron core legs22AL and22AR (first iron core legs), an upper portion yoke22AU (first upper portion yoke) connecting the upper end portions of the iron core legs22AL and22AR, and a lower portion yoke22AD (first lower portion yoke) connecting the lower end portions of the iron core legs22AL and22AR.

Similarly, the iron core blocks22B includes a pair of vertical iron core legs22BL and22BR (second iron core legs), an upper portion yoke22BU (second upper portion yoke) connecting the upper end portions of the iron core legs22BL and22BR, and a lower portion yoke22BD (second lower portion yoke) connecting the lower end portions of the iron core legs22BL and22BR, and is configured to surround the upper, lower, left and right outer peripheries of the iron core block22A. Further, the iron core block22C includes a pair of vertical iron core legs22CL and22CR (third iron core legs), an upper portion yoke22CU (third upper portion yoke) connecting the upper end portions of the iron core legs22CL and22CR, and a lower portion yoke22CD (third lower portion yoke) connecting the lower end portions of the iron core legs22CL and22CR, and is configured to surround the upper, lower, left and right outer peripheries of the iron core block22B.

The outer side curvature radiuses in the curved portions of the upper portion yoke portions of the iron core blocks22A,22B and22C are referred to as R2AU, R2BU, and R2CU, and the outer side curvature radiuses in the curved portions of the lower portion yoke portions of the iron core blocks22A,22B and22C are referred to as R2AL, R2BL, and R2CL. Here, it is preferable that the ratio of the upper and lower curvature radiuses “R2BL/R2BU” in the iron core block22B is about 2 to 8, and the ratio of the upper and lower curvature radiuses “R2CL/R2CU” in the iron core block22C is about 3 to 12. More preferably, the ratio “R2BL/R2BU” is about 2 to 4, and the ratio “R2CL/R2CU” is about 3 to 6.

Here, the significance of the range of each ratio described above will be explained. First, it is assumed that the ratio “R2BL/R2BU” is less than 2, or the ratio “R2CL/R2CU” is less than 3. When these ratios are to be realized by increasing the curvature radiuses R2Band R2C(seeFIG. 3) of the inner side curved portions, the dead space on the upper portion of the iron core22increases. Further, when these ratios are to be realized by decreasing the curvature radiuses R2BLand R2CL, it becomes necessary to push down the curved portions of the lower portion yoke portions of the iron core blocks22B and22C. In either case, there arises a problem that the volume of the iron core22increases and the loss increases.

Next, it is assumed that the ratio “R2BL/R2BU” is greater than 8, or the ratio “R2CL/R2CU” is greater than 12. When these ratios are to be realized by decreasing the curvature radiuses R2Band R2C(seeFIG. 3) of the inner side curved portions, the distortion of the iron core blocks22B and22C becomes larger in the inner side curved portions, the iron core material cannot keep its original performance and the loss increases. Further, when these ratios are to be realized by increasing the curvature radiuses R2BLand R2CL, the curved portions of the lower portion yoke portions of the iron core blocks22B and22C become larger, the volume of the iron core22increases and the loss increases. Therefore, as described above, it is preferable that the ratio “R2BL/R2BU” is about 2 to 8, and the ratio “R2CL/R2CU” is about 3 to 12. In addition, the dimensions of each portion of the iron core12and the support plate portion13are the same as those of the iron core22and the support plate portion23.

As described above, according to the present embodiment, since the iron cores12and22are divided into a plurality of iron core blocks12A,12B,12C,22A,22B and22C and each iron core block is supported at the inner side of the upper portion yoke portion, it is possible to divide the weights of the iron cores12and22to support the same. As a result, distortions of the iron cores12and22and the stress in the laminating direction can be reduced, and the iron cores12and22with low losses can be realized. In addition, with regard to the iron core blocks22B and22C, the curvature radiuses R2BLand R2CLof the curved portions appearing on the outer periphery of the lower portion are made twice or more, or three times or more the curvature radiuses R2BUand R2CUof the curved portions appearing on the outer periphery of the upper portion. In this way, the volumes and weights of the iron cores12and22can be reduced.

Further, since the curvature radiuses R2Band R2Cof the inner side curved portions of the iron core blocks12B,12C,22B and22C are made equal to or less than the plate thicknesses T3Band T3Cof the support plates13B,13C,23B and23C, the support plates13B,13C,23B and23C can be formed in a flat plate shape. In this way, the upper portion yoke portions of the iron core blocks12A,12B,12C,22A,22B and22C can be arranged close to each other, the amount of the magnetic ribbon constituting the iron cores12and22can be reduced, and the weights and volumes of the stationary induction electric device T1and the tank storing the same can be reduced.

Second Embodiment

Next, a stationary induction electric device T2according to a second embodiment of the invention will be described.

FIG. 5is a partially cutaway front view of the stationary induction electric device T2. InFIG. 5, parts corresponding to those inFIGS. 1 to 4are given the same reference signs and numerals, and the description thereof may be omitted in some cases.

InFIG. 5, the stationary induction electric device T2is a transformer with a single phase tripod structure, and includes iron cores12and22, a winding11, support plate portions33and43, an upper portion fixing member14, a lower portion fixing member15, a plurality of support posts16, and support beam portions17and27.

Here, the configurations of the iron cores12and22, the winding11, the upper portion fixing member14, the lower portion fixing member15, and the support posts16are the same as those of the first embodiment (seeFIG. 2). Like the support plate portions13and23of the first embodiment, the support plate portions33and43are formed in a flat plate shape, and include support plates33A (first support plate),33B (second support plate),33C (third support plate),43A (first support plate),43B (second support plate), and43C (third support plate) supporting the iron core blocks12A,12B,12C,22A,22B and22C respectively. However, the lengths of the support plate portions33and43in the front-rear direction (the direction perpendicular to the paper sheet) are in the range in which they come into contact with the iron cores12and22, and are slightly shorter than the support plate portions13and23of the first embodiment.

The support beam portions17and27include support beams17A,17B,17C,27A,27B and27C, the cross-sectional shapes of which are substantially rectangular. These support beams are fixed so as to bridge the upper surfaces of the fixing members14A,14B and14C on the front surface and on the rear surface which are not shown in the drawing. The support plates33A,33B,33C,43A,43B and43C are fixed so as to bridge the upper surfaces of the support beams17A,17B,17C,27A,27B and27C, and support the corresponding iron core blocks12A,12B,12C,22A,22B and22C.

According to the present embodiment, similar to the first embodiment, the iron cores12and22with low losses can be realized, the amount of the magnetic ribbon constituting the iron cores12and22can be reduced, and the weights and volumes of the stationary induction electric device T2and the tank storing the same can be reduced. Moreover, according to the embodiment, instead of the support plate portions13and23(seeFIG. 2) of the first embodiment, the support beam portions17and27, and the support plate portions33and43supporting the same from below are applied, and the widths of the support beam portions17and27in the left-right direction is made smaller than those of the support plate portions33and32. As a result, the support plate portions33and43can be made thinner than the support plate portions13and23of the first embodiment, and the weight of the whole can be reduced. This is because the support beam portions17and27can realize a structure having a higher section modulus with a smaller sectional area comparing with the support plate portions33and34.

Third Embodiment

Next, a stationary induction electric device T3according to a third embodiment will be described.

FIG. 6is a partially cutaway front view of the stationary induction electric device T3. InFIG. 6, parts corresponding to those inFIGS. 1 to 5are given the same reference signs and numerals, and the description thereof may be omitted in some cases.

InFIG. 6, the stationary induction electric device T3is a transformer with a single phase tripod structure, and includes iron cores12and22, a winding11, support plate portions33and32, an upper portion fixing member14, a lower portion fixing member15, a plurality of support posts16, and support beam portions18and28.

Here, the configurations of the iron cores12and22, the winding11, the upper portion fixing member14, the lower portion fixing member15, the support posts16are the same as those of the first embodiment (seeFIG. 2). In addition, among the support plate portions33and43, the configurations of the support plates33B,33C,43B and43C other than those on the innermost periphery are the same as those of the second embodiment (seeFIG. 5). The support plates33A and43A positioned on the innermost periphery are formed in the same manner as the support plates13A and23A in the first embodiment (seeFIG. 2). That is, the support plates33A and43A are arranged so as to bridge the fixing members14A on the front surface and on the rear surface which are not shown in the drawing, are fixed by these fixing members14A, and support the iron core blocks12A and22A.

The support beam portions18and28include support beams18B,18C,28B and28C. These support beams are arranged along the left and right ends of the support plates33B,33C,43B and43C so as to bridge the fixing members14B and14C on the front surface and on the rear surface which are not shown in the drawing, and are fixed to these fixing members14B and14C. Here, the support beams18B,18C,28B and28C are formed with their cross-sections in a substantially right-angled isosceles triangular shape, and are arranged such that the width in the left-right direction becomes smaller as going downwards.

A gap in a substantially right-angled isosceles triangular shape is generated between the curved portions on the outer sides of the iron core blocks12A and22A and the curved portions on the inner sides of the iron core blocks12B and22B. Similarly, a gap in a substantially right-angled isosceles triangular shape is generated between the curved portions on the outer sides of the iron core blocks12B and22B and the curved portions on the inner sides of the iron core blocks12C and22C. In the present embodiment, the support beam portions18and28are inserted through these gaps, and thus the space generated between the iron core blocks can be effectively used.

As described above, according to the embodiment, similar to the first and second embodiments, the iron cores12and22with low losses can be realized, the amount of the magnetic ribbon constituting the iron cores12and22can be reduced, and the weights and volumes of the stationary induction electric device T3and the tank storing the same can be reduced. Moreover, according to the embodiment, the space generated between the iron core blocks can be effectively used, and as a result, the amount of the magnetic ribbon constituting the iron cores12and22can be further reduced.

The invention is not limited to the aforementioned embodiments, and all kinds of variations are possible. The aforementioned embodiments are exemplified for a better understanding of the invention, and are not necessarily limited to those having all of the described configurations. Moreover, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment, and the configuration of one embodiment may be added with the configuration of another embodiment. In addition, a part of the configuration of each embodiment may be deleted, or added and/or replaced with another configuration. Possible variations to the aforementioned embodiments are, for example, as follows.

(1) The iron cores12and22in each of the above-described embodiments are wound iron cores in which the amorphous magnetic ribbons are laminated. However, applicable iron cores are not limited thereto, and the invention may also be applied to iron cores in which electromagnetic steel sheets are laminated and other iron cores.

(2) In each of the above-described embodiments, the stationary induction electric devices T1to T3are single phase tripod transformers. However, the invention may also be applied to various kinds of stationary induction electric devices such as three-phase five-leg transformers, three-phase tripod transformers, and reactors.

(3) In the support plate portions13,23,33and34in each of the above-described embodiments, flat plate-shaped support plates (13A, etc.) are applied. However, the shape of the support plate is not limited to the flat plate shape, and may be, for example, an arcuate shape slightly protruding upwards. In this case, the shapes of the lower surfaces of the upper portion yoke portions of the iron core blocks12A,12B,12C,22A,22B and22C may also be curved into an arcuate shape along the corresponding support plates.

(4) The support beams17A,17B,17C,27A,27B and27C in the second embodiment have substantially rectangular cross-sectional shapes. However, as these support beams, L steel, H steel, and I steel may be applied, and a combination of a flat plate and a stay may also be applied.

(5) The cross-sectional shapes of the support beams18B,18C,28B and28C in the third embodiment are substantially right-angled isosceles triangular. However, those with other cross-sectional shapes may also be applied. That is, as long as they have a cross-sectional shape in which the width becomes smaller as going downwards, similar to the third embodiment, an effect of effectively using the space can be achieved.

REFERENCE SIGNS LIST

2: iron core2A,2B,2C: iron core block3: support plate portion3A,3B,3C: support plate11: winding11A: primary winding11B: secondary winding12,22: iron core12A,22A: iron core block (first iron core block)12B,22B: iron core block (second iron core block)12C,22C: iron core block (third iron core block)13,23: support plate portion13A,23A: support plate (first support plate)13B,23B: support plate (second support plate)13C,23C: support plate (third support plate)14: upper portion fixing member14A,14B,14C: fixing member15: lower portion fixing member16: support post17,27: support beam portion17A,17B,17C,27A,27B,27C: support beam18,28: support beam portion18B,18C,28B,28C: support beam22AD: lower portion yoke (first lower portion yoke)22AU: upper portion yoke (first upper portion yoke)22BD: lower portion yoke (second lower portion yoke)22BU: upper portion yoke (second upper portion yoke)22CD: lower portion yoke (third lower portion yoke)22CU: upper portion yoke (third upper portion yoke)22AL,22AR: iron core leg (first iron core leg)22BL,22BR: iron core leg (second iron core leg)22CL,22CR: iron core leg (third iron core leg)33,34: support plate portion33A,43A: support plate (first support plate)33B,43B: support plate (second support plate)33C,43C: support plate (third support plate)T1to T3: stationary induction electric device