JP2924274B2 - Manufacturing method of disk winding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a capacity of several hundred MV.
A large-capacity transformer of A is connected to an ultra-high-voltage power system such as 154 kV or 275 kV, in particular, a disk coil is stacked in the axial direction, and the conductors at the inner end or outer end are alternately connected. The present invention relates to a method for manufacturing a twin-winding annular disk winding which is entirely connected in series.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a conventional disk winding.
The left side of the figure is the inner diameter side, and the right side is the outer diameter side. Most of the large-capacity transformers are three-winding transformers composed of high-voltage windings, medium-voltage windings and low-voltage windings, and the disk winding 100 as shown is connected to a 154 kV or 275 kV system as described above. Often used for pressure or medium voltage windings.

[0003] The disk winding 100 is star-connected to the other two phases. Terminals drawn out from the upper part are line terminals 91 connected to the ultra-high voltage system. Neutral terminals (not shown) are drawn out from the lower part and connected to neutral points of other phases. To form a neutral point.

The disk winding 100 is composed of several tens of disk coils. In this figure, the upper three disk coils 11, 1
Only 2 and 13 are shown. Static plate 9
Numeral 2 is provided to reduce the electric field concentration at the axial end of the disk winding 100.
Is connected to the crossover portion 21 drawn from the disk coil 11, and the line terminal 91 is connected to the static plate 92.
Are drawn from.

[0005] The disk coils 11 and 12 are the transition portions 22 on the inner diameter side, and the disk coils 12 and 13 are the transition portions 23 on the outer diameter side.
The same applies to the lower disk coil (not shown).

The disk coils 11, 12, and 13 have four turns, and the winding number is assigned to the conductor for each turn from 1 to 12. Of course, the actual disk coil is not limited to four turns. The disk coil 11 has an outer diameter end conductor 111 having a winding number 1, an outer diameter end conductor 113 having a winding number 4, and a middle conductor having winding numbers 2 and 3 between these end conductors. A reinforcing insulator 31 having an L-shaped cross section is attached to the end conductor 111 so as to cover the outer diameter side corner on the side of the disk coil 12. The cooling duct 5 is provided between the middle conductors 112 of the winding numbers 2 and 3, and the insulating oil as a refrigerant flows upward from below.
Disc coils 12 and 13 even if there is a difference between the inner and outer diameter sides
The same applies to the disk coil located further below which is not shown.

The static plate 92 and the disk coil 11
, A spacing piece 42 is provided between the disc coils 11 and 12, and a spacing piece 43 is provided between the disc coils 12 and 13. 4
Numerals 2 and 43 form a cooling duct through which insulating oil flows in the radial direction and oil insulation for obtaining dielectric strength between the static plate 92 and the disk coil 11, between the disk coils 11, 12 and 12, 13. It is for ensuring the distance. The number of disk coils to which the reinforcing insulators 31 to 33 are attached is ４ of the number of disk coils of the disk winding 100.
It is about.

[0008] As is well known, the winding of a transformer connected and operated to a power system is required to have a dielectric strength against lightning surge. When a lightning surge enters, the disk winding 100
It is known that the potential distribution in the winding at the head of the lightning surge wave becomes extremely unbalanced in a winding having a large number of turns as shown in FIG. The voltage generated between the disk coils 11 and 12 closest to the line terminal 91, which is the terminal into which the lightning surge enters, may reach several tens of times the equal distribution distributed in proportion to the number of turns. . Since the magnification with respect to the voltage difference between adjacent disk coils is larger as it is closer to the line terminal 91, as shown in the figure, in the disk coils 11 to 13 in the upper part of FIG. Partial conductors 111 and 12
Reinforcing insulators 31, 32, 3 having an L-shaped section on 3,131
3 is employed to ensure the dielectric strength against lightning surge without increasing the insulation distance.

FIG. 4 is a cross-sectional view of the conductor 2 in which an odd number of relatively small rectangular wires 202 insulated and coated with formal or the like are bundled and insulated by an insulating coating 201. The wire 202 is a conductor that is manufactured so as to be displaced so that each position rotates, and is generally called a dislocation conductor. In this figure, the number of flat wires 202 is seven, but the number of dislocation conductors used for actual disk winding is often about twenty.

As described above, the winding of a large-capacity transformer of several hundred MVA has a considerably large current even at a very high voltage such as 154 kV, so that the required conductor cross-sectional area becomes large. Therefore, the rectangular wire 202 having a small cross section
In many cases, a so-called dislocation conductor is used in which a plurality of bundles are bundled and the insulating coating 201 is collectively applied. Such a conductor 2
Then, the overall cross-sectional dimension is large, for example, the rectangular wire 202
Has a cross-sectional dimension of 7 mm x 2 mm, 19 pieces, insulating coating 20
Assuming that the thickness of 1 is 1 mm, the size of the conductor 2 is 17 mm × 2
2 mm.

In FIG. 3, the highest voltage is generated between the disk coils 11 and 12 at the end conductor 111 and the end conductor 121. An electric field is applied to the lower corner of the end conductor 111 near the line terminal 91. Is more concentrated, a reinforcing insulator 31 is attached so as to surround this corner in order to improve the dielectric strength of this part. End conductors 111 and 12
When the dimension for maintaining the dielectric strength with respect to 1 is secured by the spacing piece 31, the spacing between the other conductors may be smaller than the size of this portion, so the shape of the spacing piece 41 is such that the portion where the reinforcing insulator 31 protrudes downward is formed. Notched shape, reinforcing insulator 3
Except for the part where the number 1 is located, the vertical dimension of the spacing piece 41 in the figure is constant. The same applies to the spacing pieces 42 and 43 and the lower spacing piece (not shown).

Since the generated voltage is large in the spacers 41, 42 and 43, the reinforcing insulators 31, 32 and 33 are attached and the dimensions of the spacers are increased to improve the dielectric strength. Therefore, the spacing piece at the center of the disc winding 100 (not shown) has a small size.

As shown in FIG. 3, the lower surface of the reinforcing insulator 31 attached to the end conductor 111 and the lower surfaces of the middle conductor 112 and the end conductor 113 coincide with the same surface of the spacing piece 42. The partial conductor 111 itself is a middle conductor 112,
It is positioned above the end conductor 113 by the thickness of the reinforcing insulator 31. This is the same for the end conductors 123 and 131. Therefore, the portions of the spacing pieces 41, 42, 43 that are in contact with the upper portions of the end conductors 111, 123, 131 are cut out by a size corresponding to the thickness of the reinforcing insulators 31, 32, 33. By the way, the interval pieces 41, 42, 43
The main part has a thickness of about 10 mm, and the reinforcing insulator has a thickness of about 2 mm.

FIG. 5 is a view taken in the direction of the arrow A in FIG. 3, and the same components as those in FIG. In this figure, the line terminal 91 once enters the static plate 92 and is electrically connected to the disk coil 11 via the bridging portion 21. The disc coils 11 and 12 are connected on the inner diameter side by a transition portion 22 and the disc coil 1
2 and 13 are connected to each other by a crossover portion 23 on the outer diameter side. Since the crossover portions 21, 22, and 23 are actually formed by bending the conductor 2, they are bent with a much larger curvature than in the drawing. In this figure, the illustration of the reinforcing insulations 31, 32, 33 is omitted to clearly show the positional relationship of the conductors.

The transition portion 21 enters the disc coil 11 and becomes an end conductor 111, which turns from the left side in the figure and makes one turn to the right to return. Then, it is sunk into the inner diameter side of the crossover portion 21 by the bent portion 115. Since the end conductor 111 is located above the middle conductor 112 by the thickness of the reinforcing insulator 31, the end conductor 111 is slightly bent to the lower left at the bent portion 116 as shown in FIG.
At the axial position of the middle conductor 112. The rear end conductor 113 is connected in this order, and the connection portion is bent so that the radial position of the conductor is changed by one conductor similarly to the bent portion 115.

The end conductor 113 is connected to an end conductor 123 of the disk coil 12 via a transition portion 22 on the inner diameter side. The end conductor 123 is, like the end conductor 111, a middle conductor 122 or an end conductor. It is positioned above the 121 by the thickness dimension of the reinforcing insulator 32. A bending process for changing the conductor position in the radial direction is performed at the portion where the end conductor 123 moves to the middle conductor 122 of the winding number 6 in the same manner as the bent portion 115 of the disk coil 11, and the thickness of the reinforcing insulator 32. Bending of the bending portion 126 for axial movement by the dimension is also performed. Hereinafter, the end conductor 121 is wound from the inner diameter side to the outer diameter side in reverse to the disk coil 11. The connection from the disc coil 12 to the disc coil 13 via the transition portion 23 is similar to the connection to the disc coil 11 at the transition portion 21 and will not be described.

[0017]

As described above, the end conductor 11 to which the reinforcing insulators 31, 32, and 33 are attached is described.
1, 123, 131, and the like are configured to be separated from each other in the axial direction by a dimension corresponding to the thickness of the reinforcing insulator in order to increase the distance between opposing conductors where a large voltage difference occurs. Therefore, it is necessary to bend the conductor in the axial direction near the transition between adjacent disk coils. Transition part 2
The bent portions 115 and the bent portions 116, 126, and 136 are basically the same, although the bent angles and dimensions are different. Such a bending operation must be performed carefully, since the insulation of the conductor 2 must not be damaged. Therefore, the bent portions 116, 126, 13
6, the increase in the working time of the winding of the disc winding 100 due to the addition of the bending work having a dimension equivalent to the thickness of the reinforcing insulator becomes a value that cannot be ignored, and the work of the winding of the disc winding 100 There is a problem that time increases.

An object of the present invention is to provide a manufacturing method capable of suppressing an increase in working time of a winding of a disk winding provided with a disk coil having such end conductors shifted in the axial direction. Is to provide.

[0019]

According to the present invention, in order to solve the above-mentioned problems, a plurality of disk coils formed by winding a plurality of turns with an insulated conductor overlapped in a radial direction are provided. Radial ends on the outer diameter side or inner diameter side of adjacent disk coils, which are stacked in the axial direction with a predetermined equal number of insulating pieces spaced equally in the circumferential direction interposed therebetween. Wherein the conductors are alternately electrically connected to each other, wherein at least one of the plurality of disc coils has a radius on the outer diameter side. A reinforcing insulator having an L-shaped cross section is attached to either the outer diameter corner of the conductor at the direction end or the inner diameter corner of the conductor at the radial end at the inner diameter so as to cover only the corner. Conductor at the radial end of the spacing piece. A notch having an axial depth corresponding to an axial thickness of a radial flat plate portion of the reinforcing insulator is provided at a portion facing the reinforcing insulator in the axial direction, and the insulating reinforced circle is provided. The part where the conductor at the radial end on the outer diameter side of the plate coil moves to the conductor adjacent to the inner diameter side of the conductor, or the part where the conductor at the radial end on the inner diameter side moves to the conductor adjacent to the outer diameter side of this conductor The operation of shifting the axial position of the conductor by the dimension corresponding to the axial thickness of the radially flat plate portion of the reinforcing insulator at the conductor portion of the conductor is not performed at the time of the winding operation of the disk winding, but at the time of the winding operation. A gap formed between the conductor constituting the insulating-reinforced disk coil and the spacing piece and corresponding to the axial thickness of the radially flat plate portion of the reinforcing insulator is formed in the disk winding. Depending on the axial tightening force during the pre-drying process It shall be filled by shifting the axial position of the conductor in serial conductor portion.

[0020]

In the construction of the present invention, a portion of the insulation-reinforced disk coil that transitions from a conductor at the radially outer end on the radially outer end to a conductor adjacent to the radially inner end of the conductor or a conductor at the radially radial end at the radially inner end of the conductor. The work of shifting the axial position of the conductor by the dimension corresponding to the axial thickness of the radial flat plate portion of the reinforcing insulator having an L-shaped cross-section at the portion of the conductor portion which is shifted from the conductor to the conductor adjacent to the outer diameter side of this conductor, It is not performed at the time of winding work of this disk winding,
A gap corresponding to the axial thickness of the radially flat plate portion of the reinforcing insulator, formed between the conductor constituting the insulating-reinforced disk coil and the spacing piece during the winding operation,
By displacing the axial position of the conductor in the conductor portion by the axial tightening force at the time of the pre-tightening drying treatment of the disk winding, the conductor is packed by shifting the axial position, thereby equivalent to the thickness dimension of the reinforcing insulator at the time of winding work. This eliminates the need for bending the conductor.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 1 is a sectional view of only the upper part of a disk winding showing a first embodiment of the present invention at the end of the winding operation. The same components as those in FIG. Detailed description is omitted. The difference between FIG. 3 and FIG.
1 and the spacing piece 41, and gaps between the other conductors 112 and 113 of the disc coil 11 except for the end conductor 111 and the spacing piece 42, respectively. Middle conductor 1 which is a conductor of another disk coil 11
12. This is the same axial position as the end conductor 113. The same applies to the disc coils 12 and 13.
A gap is provided between each of the disc coils 3 and 131 and each of the spacing pieces 42 and 43. Instead, the conductors forming the disc coils 12 and 13 are located at the same axial position. This is illustrated in FIG.
5 shows a state in which the bent portions 116, 126, and 136 described in FIG. 5 are not provided, and indicates that such a bent portion is not bent in the winding operation.

This bending process utilizes the fact that it bends naturally by the axial tightening force in the pre-tightening drying process, which is a process after the winding operation of the disk winding 100 is completed. It is to be in the same state as processed.

FIG. 2 shows the disk winding 100 after the pre-tightening drying process.
5 is different from FIG. 5 only in that the bending position and angle of the conductor 2 are different from those in FIG. 5 by a dimension equivalent to the thickness of the reinforcing insulator. Since it is not artificially bent, the bent portion 116A
Is bent in such a manner as to incline over the entire space between the right-side spacing piece 411 and the left-side spacing piece 412 as a part of the spacing piece 41. This is because the bending force on the bent portion 116A is the tightening force 51,5 at the time of the pre-tightening drying process of the disk winding 100.
This is because the conductor 2 is supported by the spacing pieces 411 and 412 on both sides when the conductor 2 is bent.

Whether the conductor 2 can bend the bent portion 116 by the pre-tightening force will be discussed below. The force required for bending is expressed by the following equation. W = v _max · 3EI / L ³ １ (1) where, v _max ; the amount of deflection (here, the thickness of the reinforcing insulator 31) E: Young's modulus of conductor material (in the case of copper, 1.2 × 10
¹¹ N / m ² ) I; Second moment of area of conductor 2 (according to the following formula) L; Dimension between spacing pieces 411 and 412 I = a ³ bn / 12 ‥‥‥‥‥‥‥‥‥‥‥‥‥ ‥‥‥‥‥‥‥‥‥ (2) Here, a: width dimension of a flat wire constituting the dislocation conductor 2 b; similarly thickness dimension n; number of flat wires Also, the surface pressure σ applied to the dislocation conductor 2 is The following equation is obtained. σ = W / {c · b · (n−1) / 2} (3) where, c: circumferential dimension (width) of spacing pieces 411, 412 )

For example, the force required to bend the bent portion 116A of the dislocation conductor 2 used for the disk winding of a transformer having a capacity of 450 MVA and an insulation class of No. 200 is 2 × 10 ³ (N).
The surface pressure between the conductor 2 and the spacing piece at this time is 5 × 10
It is set to about ⁶ (N / m ² ).

As a typical value of the transformer having the above-mentioned capacity, it is assumed that the transposition conductor 2 is composed of 19 rectangular wires of 7 mm × 2 mm, and the dimension L between the spacing pieces is 75 mm (the spacing piece 41).
The circumferential width c = 25 mm), 2 mm the thickness of the reinforcing insulator 31, thus, v When _{ma x} = 2 mm, cross-sectional secondary moment I of dislocations conductor 2 assigns each value in (2) Is obtained. ^{I = (7 × 10 -3)} 3 · 2 × 10 -3 · 19/12 = 1.09 × 10 -9 (m 4)

When the force W and the surface pressure σ required to bend the conductor 2 are obtained by substituting these into the equation (1), the following values are obtained. W = 2 × ¹⁰⁻³ · 3 · 1.2 × 10 ¹¹ · 1.09 × 10 ⁻⁹ / (75 × 10 ⁻³ ) ³ = 1.86 × 10 ³ (N) σ = 1.86 × 10 ³ / {25 × 10 ^-3 · 2 × 10 ^-3 · (19-1) / 2} = 4.13 × 10 ⁶ (N / m ² )

On the other hand, the surface pressure when the disk winding 100 is pre-tightened includes the amount of drying shrinkage of an insulating material such as a spacing piece and an insulating coating of a conductor, the electromagnetic force generated by a short circuit accident when the transformer is operated, and the like. Is set to 10 × 10 ⁶ (N / m ² ) or more in consideration of the bending part 116A,
It can be concluded that 126A and 136A are easily formed.

In the pre-tightening drying process, the bent portion 116
Since A, 126A and 136A are formed, this bending work is not required at the time of winding work, and the time required for winding work can be reduced.

[0030]

As described above, the present invention is directed to a portion where a conductor is transferred from the outer radial end portion of the insulating-reinforced disk coil to the conductor adjacent to the inner radial side of the conductor or the inner radial direction. A portion of the conductor that transitions from the conductor at the end to the conductor adjacent to the outer diameter side of the conductor, and adjusts the axial position of the conductor by the dimension equivalent to the axial thickness of the radial flat plate portion of the reinforcing insulator having an L-shaped cross section. The shifting operation is not performed during the winding operation of the disk winding, and the reinforcing insulating material formed between the conductor constituting the insulating-reinforced disk coil and the interval piece during the winding operation is formed. The gap corresponding to the axial thickness dimension of the radial flat plate portion is filled by shifting the axial position of the conductor at the conductor portion by the axial tightening force at the time of the pre-tightening drying treatment of the disk winding. This allows the conductor to be bent during winding work. Is not required, the effect of the time period by winding work no longer needed bending is shortened is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a disk winding at the end of a winding operation according to an embodiment of the present invention.

FIG. 2 is a view of the disk winding in FIG.

FIG. 3 is a sectional view of a main part of a conventional disk winding.

FIG. 4 is a sectional view of the dislocation conductor of FIG. 3;

FIG. 5 is a view taken in the direction of arrow A in FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 disc winding 2 transposition conductor (conductor) 11 disc coil 111 end conductor 112 middle conductor 113 end conductor 115 bent part 116 bent part 116A bent part 12 disk coil 121 end conductor 122 middle conductor 123 end conductor 125 bent portion 126 bent portion 126A bent portion 13 disc coil 131 end conductor 132 middle conductor 133 end conductor 135 bent portion 136 bent portion 136A bent portion 21 transition portion 22 transition portion 23 transition portion 31 reinforcing insulator 32 reinforcing insulator 33 Reinforcement insulator 41 Spacing strip 42 Spacing strip 43 Spacing strip

Claims (1)

(57) [Claims] A plurality of disk coils, each of which is formed by winding a plurality of turns by superposing an insulated conductor in a radial direction and winding them a plurality of turns, is made of an insulating material in which a predetermined number of the coils are equally arranged in a circumferential direction. The disk winding is formed by stacking in the axial direction with the spacing piece between, and the conductors at the radial ends on the outer diameter side or inner diameter side of adjacent disk coils are electrically connected alternately. The manufacturing method, wherein at least one or more of the plurality of disk coils is an outer radial corner or an inner radial edge of a conductor at an outer radial end. A reinforcing insulator having an L-shaped cross-section is attached to any one of the inner corners of the conductor on the inner diameter side so as to cover only the corner, thereby reinforcing the insulation, and the radial end of the spacing piece. The reinforcing insulator is provided at a portion facing the reinforcing insulator in the axial direction through the conductor of A notch having an axial depth corresponding to an axial thickness of a radial flat plate portion of the product is provided, and a conductor at a radial end portion on an outer diameter side of the insulatingly reinforced disk coil has an inner diameter of this conductor. The portion of the conductor that transitions to the conductor adjacent to the inner side or the portion that transitions from the conductor at the radial end on the inner diameter side to the conductor adjacent to the outer diameter side of this conductor. The work of displacing the axial position of the conductor by a considerable dimension is not performed during the winding work of the disk winding, and the conductor and the spacing piece that constitute the insulation-reinforced disk coil during the winding operation are not used. A gap formed between the reinforcing insulator and the thickness in the axial direction of the flat plate portion in the radial direction is formed between the conductor portion and the conductor portion by the axial tightening force at the time of the pre-tightening drying process of the disk winding. Packing by shifting the axial position Characteristic manufacturing method of disk winding.