JP2794975B2 - Transformer core - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron core for a disassembled and transportable transformer which is disassembled and transported, and assembled together at an installation site, due to transportation size or weight restrictions.

[0002]

2. Description of the Related Art In the case of a transformer installed in a substation in a mountainous area or in an overcrowded urban area, a fully-mounted transformer is installed at a place where the transformer is installed by means of a trailer or the like due to transportation size and weight restrictions. It is often difficult to carry. In such a case, the radiator and bushing normally attached to the transformer tank are removed and transported, or further divided into three independent single-phase transformers instead of three-phase transformers and transported. Then, this is installed as a set and electrically connected to a three-phase transformer. However, as the capacity of the transformer increases, such a method may still not allow the transportation to be restricted. Therefore, disassembling and transporting the contents of the iron core and windings of the three-phase transformer, assembling it at the installation location, injecting degassed insulating oil, and constructing an integrated oil-immersed transformer Transport transformer is adopted.

FIG. 5 is an elevation view showing a three-phase three-leg core of a conventional transformer. In the actual iron core, the cross section is configured in a substantially circular shape by stacking directional silicon steel sheets with different width dimensions,
In this figure and the following figures, only the widest silicon steel sheet is shown. 11, 12, and 13 are iron legs into which windings are inserted; 21, 22 are upper yoke magnetically and mechanically connecting the upper portions of the iron legs 11, 12, and 13; It is the lower yoke that joins. The arrows indicate the rolling direction of the grain-oriented silicon steel sheet of each iron core. As will be described later, the directions of the arrows have the excitation characteristics that the magnetic flux flows easily and the iron loss is small. In order to make the most of this excitation characteristic to make the iron core small in iron loss, all joints are 45
° angle.

[0004] The dimensions H ₅ shown on the right side of the diagram represents the height dimension of the core. On the other hand, even if the upper yoke 21, 22 is removed at the time of transportation, the weight decreases but the height dimension does not change. That is, the height H ₅ of the iron core is because it is independent of the upper yoke 21 and 22 will be determined by Tesshin'ashi 11 and 13. Therefore, such a 3-phase 3-leg iron core would not be employed when the height dimension H ₅ from entering the height limit for transportation.

FIG. 6 is an elevation view of a conventional three-phase five-legged iron core. As described above, this is a core structure adopted when it is difficult to transport the three-phase three-leg core shown in FIG.
2 and 13A, return legs 14 and 15 are provided on both sides, and these are connected to upper yoke 23, 24, 25 and 26 and lower yoke 33 and 3 respectively.
4, 35, 36.

Return legs 14, 15, upper yoke 23, 24,
Since the cross-sectional area of the lower yoke 25, 26 and the lower yoke 33, 34, 35, 36 may be approximately 60% of the iron core legs 11A, 12, 13A, the upper yoke 23, 24, 25, 26 and the lower yoke 3
The width dimensions of 3, 34, 35, 36 were changed to the upper yoke 21, FIG.
22 and the lower yoke 31, 32 can be smaller than the width dimension. Therefore, the height H ₆ of the iron core is determined as shown in FIG.
It is smaller than the height H ₅ in. Therefore, even in the case where the iron core shown in FIG. 5 cannot be transported, the iron core structure shown in FIG. 6 can be transported.

FIG. 7 is a graph showing the relationship between the direction in which the magnetic flux of the grain-oriented silicon steel sheet flows and the generated iron loss. In this figure, the horizontal axis represents the angle (°) of the direction in which the magnetic flux flows from the rolling direction, the vertical axis represents the iron loss per unit weight (W / kg), and the curve represents the maximum magnetic flux density of 1.5T and the frequency of 60H. _Z
It is a characteristic in. Naturally, it is symmetrical about the angle 0 °.

As is apparent from this figure, the iron loss at an angle of 0 ° is 1.3 (W / kg), whereas that at 90 ° is 4.2 (W / kg), which is about 3 (W / kg). It is twice.

FIG. 8 is a magnetic flux distribution diagram schematically showing the flow of magnetic flux at the joint between the iron core leg 13 and the upper yoke 22 of FIG. In this figure, since the rolling direction of the iron core leg 13 is the up and down direction of the paper as shown by the arrow, the magnetic flux 51 travels substantially straight to the joint 4 and changes the angle to a right angle at the joint 4 to change Flows as a magnetic flux 52 in the horizontal direction corresponding to the rolling direction.

FIG. 9 is a magnetic flux distribution diagram in the case where the joining portion is assumed to be horizontal. In this figure, a temporary upper yoke 22
Since the joint 4S between S and the temporary iron leg 13S is perpendicular to the rolling direction indicated by the arrow of the iron core 13S, the magnetic flux 53 in the iron core 13S goes straight to the joint 4S and enters the upper yoke 22S.
The direction changes at a right angle as the magnetic flux 54, but the upper yoke 22S
Since the rolling direction is horizontal as shown in the drawing, the magnetic flux before changing the direction causes a large iron loss shown in FIG. 7, and there is a possibility that local heating may occur in this portion. For this reason, the joint is formed at an angle of 45 ° as described above.

FIG. 10 is a schematic elevational view of the contents of the transformer during transportation, and the core is illustrated by taking the three-phase three-legged core of FIG. 5 as an example. Although there are various transport states of the contents of the transformer, in this figure, the windings 61, 62, 63 of each phase are respectively connected to the iron core legs 1
1 shows a state in which the sheet is transported while being inserted in 1, 12, and 13. The upper iron cores 21 and 22 are separately packed and transported to reduce the weight during transportation. Windings 61, 62, 6
3 can be transported with the core inserted as shown in this figure, the transformer tank itself can be used as a container for transportation, and the windings of each phase can be connected in a triangular or star connection. There is also an advantage that the lead connection for three-phase connection can be made almost in advance. If there is no restriction on the weight, the transformer with the upper yoke 21, 22 attached is transported in almost completed state. Further, when the transportation is more severe or the size is restricted, the windings 61, 62, 63 are connected to the iron legs 11, 1.
2, 13 and removed and stored in a transport tank for transportation. The iron cores are iron legs 11, 12, 13 and lower yoke 31, 3,
2 and will be transported separately. In such a case, there is a problem that a transport tank for transporting the windings 61, 62, and 63 separately is required, and the assembling time at the installation location becomes longer.

[0012] When transporting a state of FIG. 10, since the height dimension H ₅ during transportation, as described above we've determined by the position of the tip of Tesshin'ashi 11,13, the upper yoke 23,
Even if 24, 25, and 26 are removed, the height cannot be reduced.

[0013]

As described above, since the conventional transformer iron core uses a directional silicon steel plate and is joined at an angle of 45 °, even if disassembled and transported to remove the upper yoke, the transformer core will be high. There is a problem that the size cannot be reduced.

[0014] An object of the present invention is to remove the upper yoke and remove the upper yoke in order to reduce the height without increasing iron loss when performing disassembly and transportation in which only the upper yoke is inserted with the winding inserted into the iron core leg. An object of the present invention is to provide a transformer core that can be made smaller.

[0015]

According to the present invention, a plurality of upright leg iron cores and an upper yoke and a lower yoke for magnetically coupling these leg iron cores are provided. In a transformer core in which an iron core and a yoke are laminated with grain-oriented silicon steel sheets, the outermost leg iron core and the upper yoke are arranged such that the direction of the side is 35 ° to 55 ° with respect to the rolling direction.
°, a rectangular silicon steel plate having an angle in the range of ° is joined through a joint core formed by laminating, the transformer core is a three-phase three-leg core, and the transformer core is Is a three-phase five-leg core, and the transformer core is a single-phase two-leg core.

[0016]

In the structure of the present invention, the outermost leg iron core and the upper yoke are connected so that the direction of the side is 35 ° to 5 ° with respect to the rolling direction.
The magnetic flux flowing through the joint core flows along the rolling direction of the joint core by joining through a joint core in which rectangular silicon steel plates having a predetermined angle within a range of 5 ° are laminated, so that the leg core and the upper yoke are connected. Since the flow of the magnetic flux is connected, the magnetic flux always flows along the rolling direction of the silicon steel sheet, so the iron loss is about the same as the conventional transformer core, and by removing the upper yoke and this joint core during transportation Since the height dimension is reduced, it is possible to keep the height dimension during transportation within transportation restrictions.

When the transformer core is a three-phase three-leg core, the two leg cores at both ends and the upper yoke may be joined by the above-mentioned joint core, and in the case of a three-phase five-leg core, both ends are provided. In this case, a configuration may be adopted in which the return leg iron core and the upper yoke are joined by a joint iron core, and in the case of a single-phase two-leg iron core, the two leg iron cores and the upper yoke are joined by a joint iron core.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 1 is an elevational view of a three-phase three-legged iron core showing an embodiment of the present invention, and the same members as those in FIG. In this figure, the upper yoke 27 and the iron core leg 11B are joined via a joint iron core 71, and the joint iron core 71 has a square shape, and its rolling direction is a downward rightward direction as shown. The upper end where the iron core leg 11B is joined to the joint core 71 is cut horizontally, and the joint end where the yoke 27 is joined to the joint core 72 is also cut vertically. The same applies to the joint core 72, the core legs 13B, and the upper core 28.

The magnetic flux flowing vertically from the iron core leg 11B into the joint core 71 turns 45 ° to the left along the rolling direction in the joint core 71 and enters the upper yoke 27. Since the direction is set at an angle of 45 °, the magnetic flux flows along the rolling direction, so that unlike FIG. 9, the iron loss does not increase and there is no possibility that local heating occurs.

FIG. 2 is a schematic elevational view of the transformer during transportation using the iron core of FIG. 1. The same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. In this figure, upper yoke 26, 27 and joint iron core 71, 72
, And transported separately, and the contents of the transformer from which they were removed are stored in a transformer tank and transported. Height at this time is made into the size shown with H ₂ in FIG, this dimension is the height dimension of the center core leg 12. 5 is the same as that of FIG. 5, but the joint of the iron core leg 12 with the upper yoke 26, 27 has a pointed tip as shown in the figure, and the height dimension of this tip is equal to that of the upper yoke 26, 27. 27 is approximately one-half of the width dimension. Therefore, the height dimension H ₂ would have lowered by one half of the width of the upper yoke 26, 27 than the height dimension H ₅ in FIG.

By thus joining the upper and lower yokes 26, 27 and the iron core legs 11B, 13B via the joint iron cores 71, 72, the height dimension during disassembly and transportation can be reduced without impairing the excitation characteristics. Can be smaller.

Taking a three-phase three-legged iron core of about 200 MVA as an example, the diameter of the iron core leg 12 is about 700 mm.
The height at the time of transport is reduced by 350 mm, which is one-half the size.

FIG. 3 is a sectional view showing an example of a method of manufacturing a silicon steel plate 710 used for the joint iron cores 71 and 72. In this figure, the rolling direction of the strip-shaped silicon steel sheet 700 is the horizontal direction of the figure as indicated by the arrow, and the silicon steel sheet 700 is cut along cutting lines 101 and 10 at an angle of 45 ° with respect to the rolling direction.
2 and a rectangular silicon steel plate 710 whose sides are at an angle of 45 ° to the rolling direction by cutting along the cutting lines 103 and 104 perpendicular to these. As an example of an actual cutting method, a silicon steel sheet 7 is cut by cutting lines parallel to each other, such as cutting lines 101 and 102, and rising to the right in the rolling direction.
By cutting 00, a parallelogram silicon steel plate is obtained, and both sides of the parallelogram are cut to obtain a rectangular silicon steel plate 710. It is also possible to reduce the number of cuts by manufacturing the silicon steel plate 710 when manufacturing the silicon steel plate of the iron core leg 12.

FIG. 4 is a plan view showing an actual combination of silicon steel sheets at the joint. In FIG. 4A, the silicon steel plate 711 of the joint core 71 is slightly horizontally long, and
It protrudes slightly to the left with respect to the width of the silicon steel sheet 111 of 1B. The vertical dimension of the silicon steel sheet 711 in the figure is the upper yoke 2
1B, which corresponds to the width dimension of silicon steel plate 211, and therefore, the joint between silicon steel plate 711 and silicon steel plate 111 matches the line at the lower end of silicon steel plate 211. On the other hand, FIG.
The silicon steel plate 712 of the joint core 71 shown in FIG. 7B is slightly vertically long, and the joint of the iron core leg 11 with the silicon steel plate 112 is slightly lower than the line on the lower surface of the silicon steel plate 212 of the upper yoke 21.

The actual joint is formed by alternately stacking the combination of the silicon steel plates shown in FIG. 4A and the combination shown in FIG. 4B and laminating the combination to a predetermined thickness. By alternately changing the structure, the structure is joined not only magnetically but also mechanically. Such a configuration in which the joining portions are slightly shifted from each other is employed in another joining portion having an inclination of 45 °.

The joint iron core 710 shown in FIG. 3 has a rectangular shape in which the length in the upper right direction is slightly longer.
If 10 is used as it is, it can be used as a silicon steel plate 711. Since the rolling direction of the silicon steel sheet 712 is different by 90 °, the silicon steel sheet 710 is repeatedly
Twelve rolling directions. That is, all the joining iron cores 71, 7 are formed by the method of manufacturing the silicon steel plate 710 shown in FIG.
2 silicon steel plates can be manufactured.

The structure in which the portions joined in an L-shape through the joint iron cores 71 and 72 described above can be applied to the three-phase five-leg iron core shown in FIG. 6 to improve the effect. in this case,
Upper yoke 23 and return leg 14 and upper yoke 26 and return leg 1
5 will be applied.

As described above, the width of the upper yoke 23 is smaller than the width of the iron leg 11A, while the width of the iron leg 11A is small.
The protrusion of the upper tip of the iron core leg 11A is the same as in FIG.
Is half of the width of the upper yoke 23, 24, 2
The shortening of the height when performing disassembly and transportation for removing 5, 26 is smaller than in the case of FIG. However, since the width dimensions of the lower yoke 33, 34, 35, 36 are reduced due to the use of the five-leg iron core, FIG.
It is smaller than the height dimension of H ₂ core of.

In the single-phase two-legged iron core, since the central iron leg 12 of the three-phase three-legged iron core shown in FIG. 1 is removed and the upper and lower yokes are made one, the present invention is applied to the three-phase three-legged iron core. The same effect as in the case can be obtained.

As described above, the present invention is applied to the outermost iron core such as the iron core leg or the return leg and the upper yoke which is joined thereto in an L-shape, so that the height of the transformer contents during transportation can be improved. The size can be reduced. In addition to the above-mentioned types of iron cores, there are iron cores used in single-phase transformers called central leg iron cores. Since the width is less than half the width of the inserted iron leg, the height is determined by the iron leg even when the present invention is applied. The dimensions cannot be reduced.

It is not necessary to exactly match the rolling direction of the joining iron cores 71 and 72 with the angle of the side to 45 °. As is clear from FIG. 7, when the angle is around 0 °, the iron loss does not change much. Therefore, even if the angle between the rolling direction of the joint iron cores 71 and 72 and the side is shifted by about 10 °, there is no problem in practical use. Further, in general, the standard for cutting a grain-oriented silicon steel sheet is 45 ° as described above, and the cutting device is also the same.
No need to manufacture 1,72, 45 ° as described above
In the range of plus or minus 10 °, that is, 35
The angle may be in the range of ° to 55 °. If the angle of one side is smaller than 45 °, the angle of the side perpendicular to the angle is larger than 45 °, so that it is not necessary to distinguish between the plus side and the minus side.

[0032]

As described above, according to the present invention, the outermost leg iron core and the upper yoke are connected at an angle of 35 ° with respect to the rolling direction.
The magnetic flux flowing in the joint core flows along the rolling direction of the joint core by joining through a joint core in which rectangular oriented silicon steel sheets having a predetermined angle within a range of from 55 ° to 55 ° are laminated. Since the flow of magnetic flux between the iron core and the upper yoke is connected, the magnetic flux always flows along the rolling direction of the silicon steel sheet, so the iron loss is about the same as the conventional iron core. When removed, the height dimension is reduced, so that the height dimension during transportation can be kept within transportation restrictions. For example, while the conventional capacity of up to about 150 MVA has been possible by using a three-phase three-leg iron core and disassembling and transporting by removing only the upper yoke, the present invention allows up to about 200 MVA. The effect is obtained.

As a result, even in the case where disassembly and transport such that the windings and the iron core must be transported separately must be adopted, the transformer can be integrated with the other iron cores and the windings simply by removing the upper yoke. Since it is possible to transport in a state where it is stored in the tank, the effect of shortening the time for assembling at the installation location can be obtained.

When the transformer core is a three-phase three-leg core, the two leg cores at both ends and the upper yoke may be joined by the above-described joint core. By joining the return leg cores on both sides and the upper yoke with the joint core, and adopting a configuration in which the two leg cores and the upper yoke are joined with the joint core in the case of a single-phase two-leg iron core. The same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is an elevation view of a three-phase three-legged iron core showing an embodiment of the present invention.

FIG. 2 is a schematic elevation view of a transformer during transportation using the iron core of FIG. 1;

FIG. 3 is a cross-sectional view showing an example of a method of manufacturing a silicon steel sheet used for a joint core.

FIG. 4 is a plan view showing an actual combination of silicon steel plates at a joint.

FIG. 5 is an elevation view showing a three-phase three-leg core of a conventional transformer.

FIG. 6 is an elevation view of a conventional three-phase five-legged iron core.

FIG. 7 is a graph showing the relationship between the direction in which the magnetic flux of a grain-oriented silicon steel sheet flows and the generated iron loss.

FIG. 8 is a schematic magnetic flux distribution diagram showing the flow of magnetic flux at a joint.

FIG. 9 is a schematic magnetic flux distribution diagram in a case where a joining portion is temporarily horizontal.

FIG. 10 is a schematic elevational view of a transformer during transportation according to the present invention.

[Explanation of symbols]

 11 Iron leg (leg iron) 12 Iron leg (leg iron) 13 Iron leg (leg iron) 11A Iron leg (leg iron) 13A Iron leg (leg iron) 11B Iron leg (leg iron) 13B Iron leg (leg iron) 14 Return leg (leg iron core) 15 Return leg (leg iron core) 21 Upper yoke 22 Upper yoke 23 Upper yoke 24 Upper yoke 25 Upper yoke 26 Upper yoke 27 Upper yoke 28 Upper yoke 31 Lower yoke 32 Lower yoke 33 Lower yoke 34 Lower yoke 35 Lower yoke 36 Lower yoke 71 Joint core 72 Joint core

Claims (4)

(57) [Claims] 1. A transformer core comprising a plurality of upright leg iron cores and an upper yoke and a lower yoke for magnetically coupling these leg iron cores, wherein the leg iron core and the yoke are laminated with directional silicon steel sheets. In, the outermost leg iron core and the upper yoke,
A transformer core characterized by being joined via a joint iron core formed by stacking rectangular silicon steel plates whose sides have an angle in the range of 35 ° to 55 ° with respect to the rolling direction. 2. The transformer core according to claim 1, wherein the transformer core is a three-phase three-leg core. 3. The transformer core according to claim 1, wherein the transformer core is a three-phase five-leg core. 4. The transformer core according to claim 1, wherein the transformer core is a single-phase two-leg core.