JP2012015210A - Disassembled and transported transformer core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core of a disassembled and transported transformer with easy assembly work, which can reduce increase in exciting current and iron loss in a lapping part connecting a lower part divided yoke core connected to each leg core and a connecting yoke core.SOLUTION: A disassembled and transported transformer core includes leg cores 2, 3, 4 vertically-arranged, and an upper part and a lower part yoke core 5, 6 connecting the upper part and the lower part of the leg cores 2, 3, 4. The lower part yoke core 6 includes lower part divided yoke cores 7a, 7b, 8a, 8b that are connected to each of the leg cores 2, 3, 4, and that are formed by laminating a plurality of steel plates divided corresponding to each of the leg cores 2, 3, 4, and connecting yoke cores 9a, 9b formed by laminating the multiple steel plates that connect between the lower part divided yoke cores 7a, 7b, 8a, 8b of the adjacent leg cores 2, 3, 4. A connecting part between the lower part divided yoke cores 7a, 7b, 8a, 8b and the connecting yoke cores 9a, 9b is formed by having a lapping part which is formed so that the abutment positions at which the end faces of the steel plates as the same laminated layer face each other are shifted in the extended direction of the lower part yoke core 6 in at least three continuous layers each other and are laminated.

Description

  The present invention relates to a disassembling / transporting transformer, and more particularly, to an iron core disassembling and improving a connecting structure for facilitating disassembling / transporting / on-site assembly of the disassembling / transporting transformer.

  Conventional large-capacity large transformers are manufactured, assembled, tested, and inspected at the factory, then disassembled into dimensions and weights that satisfy transportation restrictions, etc., transported to the installation site, reassembled, and tested. And split transport transformers that allow inspection. Conventionally, for example, in the case of disassembling and transporting a large transformer, the upper and lower yoke iron cores and the leg iron cores are connected at a total of eight locations. On the other hand, the yoke iron core may have to be further subdivided due to weight restrictions. In this case, if the subdivision is performed in consideration of workability such as assembly, eight joints can be formed only by the lower yoke iron core.

  As such an exploded transport transformer, for example, the one described in Patent Document 1 is known. According to this document, it is proposed to disassemble and transport an iron core comprising three leg iron cores arranged upright and upper and lower yoke iron cores connecting the upper and lower parts of each leg iron core. ing. In particular, in order to facilitate disassembly and transportation and reassembly, the lower yoke core that connects the lower ends of the leg iron cores is divided between the leg iron cores, and divided into lower yoke iron cores (hereinafter referred to as lower divided yoke iron cores). ) Can be transported and installed with each leg core assembled. The lower divided yoke cores corresponding to the respective leg iron cores are formed so as to be connected by a rectangular or trapezoidal connecting yoke iron core to simplify the reassembly operation.

  Furthermore, Patent Document 1 is provided with an overlapping portion (hereinafter referred to as a wrap portion) in which both ends of the laminated steel plates of the connecting portion of the connecting yoke iron core and the lower split yoke iron core are overlapped with each other. The abutting positions where the end faces of the steel plates are abutted are alternately shifted for each layer in the extending direction of the lower yoke core.

JP-A-10-335148

  However, according to the technique described in Patent Document 1, since the lower divided yoke cores corresponding to the respective leg iron cores are connected via the yoke iron cores, the lower yoke iron cores in the case of a three-phase transformer are connected. There are eight parts, and the number of wrap parts (joints) is doubled compared to the case where the lower divided yoke iron cores are directly connected. Moreover, since a space | gap is formed in the overlap part of a laminated steel plate and the butting | matching part of an end surface in a lap | wrap part, there exists a problem that the exciting current and iron loss in a lap | wrap part increase.

  That is, as in Patent Document 1, when the abutting positions of the end faces of the steel plates of the same layer are alternately shifted and laminated, the abutting position becomes the same position every other layer, so the effective magnetic path cross-sectional area of the iron core at the abutting position Becomes 1/2 of the cross-sectional area of the lower yoke core. For this reason, the magnetic path resistance in the wrap portion increases to increase the excitation current, and the iron loss due to the change in magnetic flux density increases, which causes a problem in terms of the performance and durability of the transformer. Further, when the wrap portion of the lower yoke core increases, the magnetic resistance increases and the magnetic balance between the upper and lower yoke cores is lost. Therefore, there is a demand for reducing the magnetic resistance at the wrap portion of the lower yoke core.

  SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a disassembled transport transformer core that is easy to assemble and has reduced magnetic resistance at the lap portion that connects the lower split yoke core connected to each leg core and connects the yoke core. There is.

  The present invention includes at least three leg iron cores arranged upright and upper and lower yoke cores connecting upper and lower portions of the leg iron cores, and the lower yoke iron cores correspond to the leg iron cores, respectively. Are formed by overlapping a plurality of steel plates, and are formed by overlapping a plurality of steel plates that connect between the lower divided yoke cores connected to the respective leg iron cores and the lower divided yoke iron cores of the adjacent leg iron cores. A connecting yoke iron core, and the connecting portion between the divided lower yoke iron core and the connecting yoke iron core has a butting position where the end faces of the steel plates of the same overlapping layer are abutted with each other in at least three consecutive layers. It has the lap | wrap part which shifted and overlap | superposed in the extension direction of the yoke core.

  According to the present invention, since the lower yoke core that connects the lower portions of the plurality of leg iron cores is divided for each leg iron core, each leg iron core and the lower divided yoke iron core are manufactured and assembled at the factory and tested. Can be transported in a connected state. Also, since the lower split yoke iron core is connected to each leg iron core, the lower split yoke iron core is placed on the base member provided at the bottom of the transformer tank at the time of installation, so that the leg iron core is brought into an upright state. Since it can be held, the assembly work can be simplified. Further, since the lower split yoke iron cores are connected and connected by the yoke iron cores, the assembling work can be further simplified.

  In particular, according to the present invention, the butted positions of the end faces of the steel sheets of the same overlapping layer of the lower divided yoke core and the connecting yoke core are shifted and overlapped in the extending direction of the lower yoke core in at least three consecutive layers. For example, the matching positions of the three-layer steel plates are dispersed. As a result, for example, when considering a magnetic path cross-sectional area composed of a three-layer steel plate group, the decrease in effective magnetic path cross-sectional area at the abutting position of the steel plates can be suppressed to 2/3. The magnetic resistance in the part can be reduced, and the exciting current and iron loss can be reduced.

  Moreover, in said case, the wrap length of the said wrap part shall be 5 mm or more and 15 mm or less, More preferably, you may be 7 mm or more and 15 mm or less. That is, as described above, since the lower split yoke iron core can be placed on the base member provided at the bottom of the transformer tank and the leg iron core can be erected, the lower split yoke iron core is connected with the connecting yoke iron core. The mechanical connection strength of the lap part is not required. Therefore, as a result of examining the relationship between the wrap length, the excitation current, and the iron loss, the inventor obtained the relationship shown in FIG. The horizontal axis of FIG. 5 is the wrap length (mm), and the vertical axis is the excitation current ratio and the iron loss ratio expressed with the excitation current and the iron loss at the wrap length of 12 mm as a reference (100%). Further, the structure of the lap portion used in the actual measurement in FIG. 5 is the lap portion structure of 9b (BB, CC, DD) of the connecting yoke iron core shown in FIG. As is apparent from FIG. 5, the iron loss tends to increase or decrease in proportion to the wrap length, but the excitation current becomes minimum when the wrap length is 12 mm, and increases rapidly when the wrap length becomes 7 mm or less than 5 mm. Further, when the wrap length exceeds 15 mm, the rate of increase of the excitation current increases. From these facts, it can be seen that when the wrap length is set to 20 mm or more in consideration of the mechanical connection strength of the lap portion as in the prior art, the excitation current and the iron loss increase.

Further, in the above case, the lap portion is arranged by gradually shifting the abutting position of at least three successive steel plates in the extending direction of the lower yoke iron core, and a plurality of subsequent steel plates The abutting positions can be shifted in the reverse direction stepwise, and the abutting positions can be arranged in a zigzag shape in the stacking direction.
Further, in the above case, the lap portion sets a plurality of groups for each of at least three consecutive layers, and the abutting positions of the plurality of steel plates belonging to each group are stepped in the extending direction of the lower yoke core. They can be staggered in the same pattern.
Moreover, in said case, it is desirable to make the length of the extension direction of the steel plate which forms a joint yoke iron core the same. According to this, since each steel plate of the connecting yoke iron core is not specified by the lamination position, the iron core stacking operation is facilitated.

  According to the disassembled transport transformer core of the present invention, the assembly work is simple, and it is possible to suppress an increase in excitation current and iron loss in the lap portion connecting the support yoke core connected to each leg core and the split yoke core. .

It is a front view which shows the iron core structure of the three-phase tripod transformer of one Example of this invention. It is a figure explaining the procedure at the time of reassembly of the transformer core of FIG. FIG. 3 is a cross-sectional view of a lower split yoke iron core and a connecting yoke iron core taken in the direction of arrows III-III in FIG. 1, showing an example in which the butted positions of three consecutive layers of steel plates are shifted in a zigzag manner and stacked. In the cross-sectional view of FIG. 3, it is a figure showing the example which repeats and laminates | stacks the butt | matching position of the steel plate of three layers which a lower split yoke iron core and a connection yoke iron core continue. It is a figure showing the relationship between the excitation current ratio and iron loss ratio with respect to the lap length of the lap | wrap part of a lower split yoke iron core and a connecting iron core.

  Hereinafter, an embodiment of an iron core structure of a divided transport transformer to which the present invention is applied will be described with reference to FIGS.

  FIG. 1 shows the structure of an iron core of a disassembled transport transformer. In the figure, a three-phase three-legged iron core 1 includes leg iron cores 2, 3, 4 arranged upright, and an upper yoke iron core 5 and a lower yoke iron core 6 that connect the upper and lower parts of the leg iron cores 2, 3, 4. And is configured. The leg iron cores 2, 3, 4 are formed by laminating a plurality of steel plates such as silicon steel plates, and a winding 10 is wound around each leg iron core 2, 3, 4. The upper yoke core 5 and the lower yoke core 6 are also formed by laminating a plurality of steel plates such as silicon steel plates. The upper yoke core 5 is divided into two parts: an upper yoke core 5 a that connects the leg cores 2 and 3, and an upper yoke core 5 b that connects the leg cores 3 and 4. The connecting portions of the leg iron cores 2 and 4 and the upper yoke iron cores 5a and 5b are cut at both ends of each laminated steel plate at 45 degrees, and are alternately meshed to be connected by a lap portion. In addition, the upper end of the laminated steel plate of the leg iron core 3 is cut at 90 degrees, and the end portions of the laminated steel plates of the upper yoke iron cores 5a and 5b are cut at 45 degrees accordingly, and the lap portions are alternately meshed with each other. It is connected.

  On the other hand, the lower yoke iron core 6 is divided corresponding to the respective leg iron cores 2, 3, 4, and the lower divided yoke iron cores 7 a, 8 a and 8 b, 7 b connected to the lower portions of the leg iron cores 2, 3, 4 are provided. I have. In addition, a connecting yoke iron core 9a that connects the divided lower yoke cores 7a and 8a of adjacent leg iron cores and a connecting yoke iron core 9b that connects the lower divided yoke cores 8b and 7b is provided.

  The connecting portions of the leg iron cores 2 and 4 and the lower split yoke iron cores 7a and 7b at both ends are connected by lap portions that are alternately meshed by cutting both ends of each laminated steel plate at 45 degrees. Further, the connecting portion between the leg iron core 3 and the lower divided yoke iron cores 8a and 8b cuts the lower end of the laminated steel plate of the leg iron core 3 at 90 degrees, and according to this, the end of the laminated steel plate of the lower divided yoke iron cores 8a and 8b Are connected by lap portions that are alternately meshed with each other. Further, the lower divided yoke iron cores 7a and 8a and the lower divided yoke iron cores 8b and 7b are connected by lap portions in which the ends of the laminated steel plates are alternately meshed with the connecting yoke iron cores 9a and 9b, respectively.

  A disassembled and assembled structure considering the transportation of the three-phase three-legged core 1 of the present embodiment configured as described above will be described with reference to FIG. In order to keep the size and weight of the three-phase three-legged iron core 1 during transportation within the limits, in this embodiment, the leg iron core 2 and the lower split yoke iron core 7a are packed and transported in a state assembled at the factory. Similarly, the leg iron core 3 and the lower divided yoke iron cores 8a and 8b, and the leg iron core 4 and the lower divided yoke iron core 7b are respectively packed and transported in a state of being assembled at the factory. Then, when assembling at the installation site, the lower split yoke iron cores 7a, 8a and 8b, 7b are mounted on the base formed on the bottom plate of the transformer tank with the leg iron cores 2, 3, 4 connected. Put. Thereby, the leg iron cores 2, 3, and 4 having an acute angle portion whose lower end is 45 degrees or 90 degrees can be stably erected, and the number of assembling steps can be reduced.

  Next, between the lower divided yoke iron cores 7a and 8a and between the lower divided yoke iron cores 7b and 8b, the lap portions of the connecting yoke iron cores 9a and 9b are formed in the gaps of the lap portions formed between the respective laminated steel plates. The laminated steel sheet is inserted and connected. Thus, after assembling the leg iron cores 2, 3, 4 and the lower yoke iron core 6, the winding 10 is inserted from the upper part of each leg iron core 2, 3, 4, and finally the upper yoke iron cores 5a, 5b are inserted. The laminated steel sheet is inserted into the lap portions of the leg iron cores 2, 3 and 4 to complete the assembly of the three-phase three-leg iron core.

  Here, the characteristic part of a present Example is demonstrated with reference to FIG. FIG. 3 is a cross-sectional view of the lower yoke iron core 6 and the leg iron core 4 composed of the lower divided yoke iron core 8b, the yoke iron core 9b, and the lower divided yoke iron core 7b, and schematically shows the flow of magnetic flux in the lower yoke iron core 6 in the cross section. It is written in. As shown in FIG. 3, the lap portion between the lower divided yoke iron cores 7 b and 8 b and the yoke iron core 9 b abuts the end surfaces of the steel sheets of the same overlapping layer with each other, and the abutting position of at least three consecutive steel sheets ( (Indicated by lines B, C, and D) are shifted from each other in the extending direction of the lower yoke core 6. In particular, in this embodiment, the lap lengths ΔL of the upper and lower layers resulting from the shifting are made the same, and the butting positions of the continuous steel plates of at least three layers are shifted stepwise in the extending direction of the lower yoke core 6. Arranged. In addition, the subsequent butting positions of the plurality of layers of the steel plates are shifted in a stepped manner, but the butting positions are shifted in the zigzag shape in the stacking thickness direction of the laminated steel plates. Note that the present invention is not limited to the zigzag shape, and as shown in FIG. 4, a plurality of groups are set for each of at least three consecutive layers, and the abutting positions of the plurality of steel plates belonging to each group Can be formed by overlapping at the same position, the lap portions being shifted stepwise in the extending direction of the lower yoke core. Further, the present invention is not limited to the lap portion structure of the embodiment shown in FIGS. 3 and 4. In short, the butt position where the end surfaces of the steel plates of the same overlapping layer are butted is arranged at least three continuous layers. In this case, the lap portions may be overlapped by shifting in the extending direction of the lower yoke core.

  According to the embodiment shown in FIG. 3 or FIG. 4, the magnetic flux flowing in the yoke has the magnetic path resistance of the gap (gap) formed at the butt position of the steel plates of each layer as indicated by arrows in the figure. Since it is high, it flows through a lap part (overlap part) with an adjacent steel plate while avoiding a gap. Here, looking at the BB, CC, and DD lines at the butt position of the steel plates of each layer, when the zigzag shape in FIG. / 4, 1/2, and 3/4. On the other hand, when the butted positions of the steel plates are repeatedly arranged stepwise and periodically as shown in FIG. 4, the ratio becomes 2/3 at any butted position.

  On the other hand, as shown in FIGS. 3 and 4, the lap portion that connects the lower split yoke iron core 7 b and the leg iron core 4 has the butt positions of the end faces of the steel plates of the same layer as shown in FIGS. The layers are alternately shifted like the F line. According to this, since the butt position is the same every other layer, the effective magnetic path cross-sectional area of the iron core on the EE and FF lines is 1 of the cross-sectional area of the lower yoke iron core 6 at any position. / 2. The same applies to the lap portions of the other leg iron cores 2 and 3 and the lower divided yoke iron cores 7a, 8a and 8b.

  That is, according to the structure of the lap | wrap part shown in the Example of FIG. 3, 4 of this invention, compared with the patent document 1 which laminated | stacked the butt | matching position of the end surface of a steel plate alternately, the magnetic flux density which flows through a lap | wrap part is compared. Since the increase / decrease is reduced, the exciting current can be reduced and the iron loss can be reduced. That is, when the magnetic flux flows in the stacking direction of the wrap portion, it is less likely to enter the overlapping layer perpendicularly, and the excitation current and iron loss can be reduced.

  On the other hand, since the lower split yoke iron cores 7a, 7b, 8a, 8b can be placed on the base member provided at the bottom of the transformer tank and the leg iron cores 2, 3, 4 can be erected, No mechanical connection strength is required for the lap portion with the connecting yoke iron cores 9a and 9b. Therefore, in order to obtain an appropriate wrap length, FIG. 5 shows the results of actual measurement of the relationship between the wrap length ΔL and the excitation current and iron loss in FIG. In the figure, the horizontal axis represents the wrap length ΔL (mm), and the vertical axis represents the excitation current ratio and the iron loss ratio expressed with the excitation current and the iron loss at the wrap length ΔL = 12 mm as a reference (100%). As is apparent from the figure, the iron loss ratio tends to increase or decrease in proportion to the wrap length, but the excitation current ratio is found to be minimal at the wrap length ΔL = 12 mm. In particular, when the wrap length ΔL is 7 mm to less than 5 mm, the excitation current ratio increases rapidly. Further, when the wrap length ΔL exceeds 15 mm, the increasing rate of the excitation current ratio increases.

  From these actual measurement results, it is understood that the excitation current and the iron loss are increased according to the conventional technique in which the lap length is set to 20 mm or more in consideration of the mechanical connection strength of the lap portion. For these reasons, the wrap length ΔL is set to 5 mm to 15 mm, and more preferably 7 mm to 15 mm.

  Note that a generally T-shaped iron core structure combining the leg iron core 3 and the lower divided yoke iron cores 8a and 8b, and a substantially L-shaped iron core structure combining the leg iron cores 2 and 4 and the lower divided yoke iron cores 7a and 7b, Since the wrap length is the same as that of the wrap portion, the frictional force at the wrap portion is the same as that of the wrap portion, and there is no particular problem when divided and transported.

In each of the embodiments of the present invention described above, it is preferable to use a low-loss silicon steel plate as the material of the divided lower yoke cores 7a, 7b, 8a, 8b and the connecting yoke iron cores 9a, 9b. According to this, coupled with the low loss due to the structure of the wrap portion of FIGS.
Loss can be greatly reduced.

  In each of the above-described embodiments, the case where there is one steel sheet per layer of the laminated iron core has been described, but the present invention is not limited to this, and a plurality of steel sheets per layer may be laminated. A similar effect can be obtained.

  Moreover, although the step-shaped wrap iron core which shifted the lap | wrap part to 3 steps | paragraphs was described as an example, when shifted to 3 steps | paragraphs or more, an exciting current and an iron loss can be reduced further.

  In each of the above-described embodiments, the present invention has been described with reference to an example in which the present invention is applied to a three-phase three-leg transformer. However, the present invention can also be applied to a single-phase two-leg transformer or a three-phase five-leg transformer. Can be achieved.

1 Three-phase three-legged iron core 2, 3, 4 Leg iron core 5a, 5b Upper yoke iron core 6 Lower yoke iron core 7a, 7b, 8a, 8b Lower divided yoke iron core 9a, 9b Connecting yoke iron core 10 Winding

Claims (5)

Comprising at least three leg iron cores arranged upright and upper and lower yoke iron cores connecting the upper and lower parts of the leg iron cores;
The lower yoke core is divided corresponding to each of the leg iron cores and formed by overlapping a plurality of steel plates, and is connected to each leg iron core, and the lower division of the adjacent leg iron cores. A connecting yoke iron core formed by overlapping a plurality of steel plates connecting between the yoke iron cores;
The connecting portion between the lower split yoke iron core and the connecting yoke iron core is overlapped by shifting the abutting position where the end surfaces of the steel plates of the same overlapping layer are abutted to each other in the extending direction of the lower yoke core in at least three consecutive layers. An exploded transport transformer core characterized by having a combined wrap portion.   2. The disassembled transport transformer core according to claim 1, wherein a wrap length of the wrap portion is 5 mm or more and 15 mm or less.   In Claim 1 or 2, the said lap | wrap part arrange | positions the said abutting position of the continuous steel plate of at least 3 layers shifting in steps in the extension direction of a lower yoke iron core, and the steel plate of several layers following this The abutting position is shifted stepwise in the reverse direction, and the abutting positions are arranged in a zigzag shape in the stacking direction.   In Claim 1 or 2, the lap part sets a plurality of groups for every at least three continuous layers, and the abutting positions of a plurality of steel plates belonging to each group are stepwise in the extending direction of the lower yoke core. Disassembled transport transformer core characterized by being formed by shifting. 5. The disassembled transport transformer core according to claim 1, wherein the steel plates forming the connecting yoke core have the same length in the extending direction. 6.

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