JPH04335509A - Manufacture of disc winding - Google Patents

Abstract

PURPOSE:To enable a reduction in winding time with a part of conductor bending during the winding work dispensed with by winding as a conductor and a spacer keep a gap and by bending the conductor to narrow the gap by a clamping force during preclamping/drying of the disc winding. CONSTITUTION:A gap between an end conductor 111 and a spacer 41 and a gap between other conductors 112, 113 of a disc coil 11 excluding the end conductor 111 and a spacer 42 are kept, and the conductor 111 is located in the same axial direction as that of the medium conductor 112 and the end conductor 113 that are the conductors of the other disc coil 11. Similarly, disc coils 12, 13 keep gaps with the respective spacers 42, 43, and the conductors constituting these disc coils 12, 13 are located in the same axial positions. Bending is made in the same state as a resultant bending from utilization of natural bending by an axial clamping force during the preclamping treatment that is a step after the disc winding 100 is up with winding work.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention has a capacity of several hundred MV.
Windings connected to ultra-high voltage power systems such as 154 kV or 275 kV of the large capacity transformer A, especially disc coils, are stacked in the axial direction, and the conductors at the inner diameter end or outer diameter end are alternately connected to each other. In particular, the present invention relates to a method of manufacturing a double ring-shaped disk winding which is entirely connected in series.

0002

[Prior Art] FIG. 3 is a cross-sectional view of a conventional disc winding wire.
The left side of the figure is the inner diameter side, and the right side is the outer diameter side. Most large-capacity transformers are three-winding transformers consisting of a high-voltage winding, a medium-voltage winding, and a low-voltage winding, and the disk winding 100 shown in the figure is a high-voltage transformer connected to a 154 kV or 275 kV system as described above. Often used for high voltage or medium voltage windings.

The disk winding 100 is star-wired with the other two phases. The terminal pulled out upward from the top is a line terminal 91 connected to the ultra-high voltage system, and the neutral point terminal (not shown) is pulled out downward from the bottom and connected to the neutral point terminal of other phases. to form a neutral point.

[0004] The disc winding 100 consists of several dozen disc coils, and in this figure, the upper three disc coils 11, 1
Only numbers 2 and 13 are shown. Static plate 9
2 is provided to relieve the electric field concentration at the axial end of the disc winding 100, and this static plate 92
The transition portion 21 drawn out from the disc coil 11 is connected to the static plate 92, and the line terminal 91 is connected to the static plate 92.
is drawn from.

The disc coils 11 and 12 are connected to a connecting piece 22 on the inner diameter side, and the disc coils 12 and 13 are connected to a connecting piece 23 on the outer diameter side.
The same applies to the lower disk coils (not shown).

[0006] The disc coils 11, 12, and 13 consist of four turns, and winding numbers 1 to 12 are assigned to the conductor of each turn. Of course, the actual disc coil is not limited to four turns. The disc coil 11 includes an end conductor 111 on the outer diameter side with winding number 1, an end conductor 113 on the outer diameter side with winding number 4, and middle conductors with winding numbers 2 and 3 between these end conductors. 112, and a reinforcing insulator 31 with an L-shaped cross section is attached to the end conductor 111 so as to cover the corner on the outer diameter side on the disk coil 12 side. A cooling duct 5 is provided between the middle conductors 112 of winding numbers 2 and 3, and insulating oil as a refrigerant flows from the bottom to the top. Disk coils 12 and 13 even though there are differences between the inner and outer diameter sides.
The same applies to the disc coil located further below, which is not shown.

Static plate 92 and disc coil 11
A spacing piece 41 is provided between the disc coils 11 and 12, a spacing piece 42 is provided between the disc coils 12 and 13, and a spacing piece 43 is provided between the disc coils 12 and 13. 4
2 and 43 form cooling ducts through which insulating oil flows in the radial direction, and are oil insulated to obtain dielectric strength between the static plate 92 and the disc coil 11, between the disc coils 11 and 12, and between 12 and 13. There are measures to ensure distance. Note that the number of disk coils to which the reinforcing insulators 31 to 33 are attached is about one-fourth of the number of disk coils of the disk winding 100.

As is well known, the winding of a transformer connected to a power system and operated is required to have dielectric strength against lightning surges. When a lightning surge invades, the disk winding 100
It is known that in a winding with a large number of turns, the potential distribution within the winding at the head of a lightning surge wave becomes extremely unbalanced. The voltage generated between the disc coils 11 and 12 closest to the line terminal 91, which is the terminal through which lightning surges enter, can reach several tens of times as much as the voltage that is evenly distributed in proportion to the number of turns. . Since the magnification for the voltage difference between adjacent disc coils is larger the closer to the line terminal 91, as shown in the figure, in the disc coils 11 to 13 at the top of the figure, each end on the inner diameter side or the outer diameter side Part conductors 111, 123,
A configuration is adopted in which reinforcing insulators 31, 32, and 33 having an L-shaped cross section are attached to 131 to ensure dielectric strength against lightning surges without excessively wasting the insulation distance.

FIG. 4 is a cross-sectional view of the conductor 2, which is constructed by bundling an odd number of relatively small rectangular wires 202 coated with formal insulation and insulating them with an insulating coating 201. The wire 202 is a conductor generally referred to as a transposed conductor, which is fabricated in a configuration in which each position is transposed so as to rotate. In this figure, the number of rectangular wires 202 is seven, but the transposed conductors used in actual disk windings are often composed of around twenty wires.

As mentioned above, the current in the winding of a large capacity transformer of several hundred MVA is quite large even if the voltage is an ultra-high voltage such as 154 kV, so the required cross-sectional area of the conductor becomes large. Therefore, the rectangular wire 202 with a small cross section
A so-called transposed conductor is often used in which a plurality of conductors are bundled and insulating coating 201 is applied all at once. Conductor 2 like this
In this case, the overall cross-sectional dimension is large, for example, the rectangular wire 202
When the cross-sectional dimensions of the conductor 2 are 7 mm x 2 mm, the number of wires is 19, and the thickness of the insulation coating 201 is 1 mm, the dimensions of the conductor 2 are 17
The size is mm x 22 mm.

In FIG. 3, the highest voltage is generated between the disc coils 11 and 12 at the end conductor 111 and the end conductor 121, and an electric field is generated at the lower corner of the end conductor 111 near the line terminal 91. In order to improve the dielectric strength of this portion, a reinforcing insulator 31 is attached to surround this corner. End conductors 111 and 12
If the spacer piece 31 has a dimension that maintains the dielectric strength with respect to the reinforcing insulator 31, the space between other conductors may be smaller than this part, so the thickness of the spacer piece 42 is the same as that of the reinforcing insulator 31. The part that protrudes downward has a cutout shape, and the spacing piece 4 except for the part where the reinforcing insulator 31 is located
The dimensions in the vertical direction of Figure 1 are constant. Spacing piece 4
The same applies to the spacing pieces 2, 43 and further below (not shown).

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

As shown in FIG. 3, since 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 41, The part conductor 111 itself is the middle part conductor 112,
It is located above the end conductor 113 by the thickness of the reinforcing insulator 31 . This also applies to the end conductors 123 and 131. Therefore, the portions of the spacing pieces 41, 42, 43 that contact the upper portions of the end conductors 111, 123, 131 are covered with reinforcing insulators 31, 32,
The cutout is made by a dimension equivalent to the thickness of 33mm. By the way, the thickness of the main parts of the spacing pieces 41, 42, 43 is approximately 1
0 mm, and the thickness of the reinforcing insulator is approximately 2 mm.

FIG. 5 is a view taken along arrow A in FIG. 4, and the same components as those in FIG. 4 are given the same reference numerals and detailed explanations will be omitted. In this figure, a line terminal 91 once enters a static plate 92 and is electrically connected to a disc coil 11 via a transition portion 21. The disc coils 11 and 12 are connected to each other by a transition section 22 on the inner diameter side, and also to the disc coil 1.
2 and 13 are connected to each other by a transition portion 23 on the outer diameter side. The transition portions 21, 22, and 23 are actually formed by bending the conductor 2, so they are bent with a much larger curvature than shown in the figure. Further, in this figure, the reinforcing insulators 31, 32, and 33 are omitted to clearly show the positional relationship of the conductors.

The transition portion 21 enters the disc coil 11 and becomes the end conductor 111, turns from the left side of the figure, rotates once to the right side, and returns. Then, the bent portion 115 slips into the inner diameter side of the transition portion 21 . Since the end conductor 111 is higher than the middle conductor 112 by the thickness of the reinforcing insulator 31, it is bent slightly to the lower left at the bending part 116 as shown in the figure, and winding number 2 is formed.
It settles at the axial position of the middle conductor 112. The rear end conductors 113 are connected in this order, but the connected portion is bent in the same way as the bent portion 115 so that the radial position of the conductor changes by one conductor.

The end conductor 113 is connected to the end conductor 123 of the disc coil 12 via the transition portion 22 on the inner diameter side, and similarly to the end conductor 111, the end conductor 113 is connected to the middle conductor 122 and the end conductor 1.
21 by the thickness dimension of the reinforcing insulator 32. Middle conductor 1 with winding number 6 from end conductor 123
22, a bending process is performed to change the conductor position in the radial direction, similar to the bending part 115 of the disc coil 11, and a bending process is performed to move the conductor position in the axial direction by the thickness of the reinforcing insulator 32. 126 bending operations are also performed. Below, the end conductor 1 is wound from the inner diameter side to the outer diameter side in the opposite direction to the disc coil 11.
I'll be 21. The connection from the disk coil 12 to the disk coil 13 via the transition section 23 is similar to the connection to the disk coil 11 at the transition section 21, so a description thereof will be omitted.

[0017]

[Problem to be Solved by the Invention] As mentioned above, the end conductor 11 to which reinforcing insulators 31, 32, and 33 are attached
Nos. 1, 123, 131, etc. are arranged at positions separated in the axial direction by a dimension equivalent 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 portion between adjacent disc coils. Crossing section 22
, 23 has an elongated S-shape, but the bent part 1
15 and the bent portions 116, 126 and 136 are basically the same although the bending angles and dimensions are different. Such bending work must be done carefully so as not to damage the insulation of the conductor 2. Therefore, the bent portions 116, 126, 136
The increase in the working time of the winding of the disk winding 100 due to the addition of bending with a dimension equivalent to the thickness of the reinforcing insulator has reached a value that cannot be ignored. There is a problem in that the amount increases.

[0018] An object of the present invention is to provide a manufacturing method capable of suppressing an increase in the winding time of a disc winding having a disc coil in which the end conductor is shifted in the axial direction. Our goal is to provide the following.

[0019]

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, a plurality of disc coils each having a plurality of turns of insulated conductors stacked in the radial direction are provided. The radial ends of adjacent disc coils on the outer or inner diameter side are stacked in the axial direction with spacer pieces made of insulating material arranged at equal intervals in the circumferential direction in a predetermined equal number. A method for manufacturing a disk winding in which conductors are alternately electrically connected to each other, and during the winding operation of the disk coil, an L is provided to insulate and reinforce the radial end conductor of the disk coil. The conductor, which has a size equivalent to the thickness of the reinforcing insulator with a letter-shaped cross section, is not bent, and a gap is maintained between the conductor and the spacing piece that make up the disc coil, and the disc winding is pre-tightened and dried. It is assumed that the conductor bends due to the axial tightening force at the time, and the gap is closed. Further, the spacer piece is provided with a notch corresponding to the axial movement due to the tightening force of the conductor to which the reinforcing insulator is attached.

[0020]

[Function] In the configuration of the present invention, during the winding work of the disc winding, the L
A conductor with dimensions equivalent to the thickness of the reinforcing insulator with a cross section is wound without bending, with a gap maintained between the conductor and the spacing piece that make up the disc coil, and the disc winding is pre-tightened. By bending the conductor using the axial tightening force during the drying process and closing the gap, bending of the conductor corresponding to the thickness of the reinforcing insulator during winding work becomes unnecessary. Further, by providing a notch in the spacer piece corresponding to the axial movement dimension due to the clamping force of the conductor to which the reinforcing insulator is attached, the bending dimension of the conductor can be made accurate.

[0021]

EXAMPLES The present invention will be explained below based on examples. FIG. 1 is a cross-sectional view of only the upper part of a disc winding according to a first embodiment of the present invention after the winding work is completed, and the same components as in FIG. Further explanations will be omitted. The difference between this figure and FIG. 3 is that the end conductor 11
1 and the spacing piece 41, and between the other conductors 112, 113 of the disc coil 11 excluding the end conductor 111 and the spacing piece 42, and instead, the conductor 111 Middle conductor 1 which is a conductor of other disc coil 11
12, it is at the same axial position as the end conductor 113. Similarly, the disc coils 12 and 13 have a gap between them and the spacing pieces 42 and 43, respectively, and instead, the conductors constituting these disc coils 12 and 13 are located at the same axial position. This corresponds to the bending part 1 explained in FIGS. 3 and 4.
16, 126, and 136 are absent, indicating that such bending portions are not bent during winding work.

This bending process takes advantage of the fact that the disc winding 100 naturally bends due to the axial tightening force during the pre-tightening drying process which is a process after the winding work is completed. It leaves it in the same condition as it was processed.

FIG. 2 shows the disc winding 100 after the pretightening and drying process.
This is a view taken along arrow B in FIG. 1, and the only difference from FIG. 4 is the dimension corresponding to the thickness of the reinforcing insulator, and the bending position and angle of the conductor 2. Since it is not artificially bent, the bent portion 116A
The spacer 41 is curved in an inclined manner over the entire space between the spacer 411 on the right side of the drawing and the spacer 412 on the left side in the figure. This means that the bending force on the bending portion 116A is the tightening force 51, 5 during the pre-tightening drying process of the disc winding 100.
This is because the conductor 2 is applied through the spacing pieces 411 and 412, and when the conductor 2 bends, it is supported by the spacing pieces 411 and 412 on both sides.

[0024] Whether or not the conductor 2 can bend the bending portion 116 by the pretightening force will be discussed below. The force required for bending is expressed by the following formula. W=vmax ・3EI/L3 ‥‥‥‥‥‥‥‥
‥‥‥‥‥‥‥‥‥‥‥‥ (1) where, vmax: Deflection amount (here, the thickness of the reinforcing insulator 31) E: Young's modulus of the conductor material (1.2 in the case of copper)
×1011N/m2) I; Moment of inertia of the conductor 2 (according to the following formula) L; Dimension between the spacing pieces 411 and 412 I = a3
bn/12 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
‥‥‥‥‥(2) Here, a; Width dimension b of the rectangular wires constituting the transposed conductor 2; Thickness dimension n; Number of rectangular wires Also, the surface pressure σ applied to the transposed conductor 2 is given by the following formula. . σ=W/{c・b・(n-1)/2} ‥‥‥‥‥‥
(3) Here, c; spacer piece 411
, 412 circumferential dimension (width)

For example, the force required to bend the bent portion 116A of the transposed conductor 2 used in the disk winding of a transformer with a capacity of 450 MVA and an insulation class of 200 is 2×103 (N
), and the surface pressure between the conductor 2 and the spacing piece at this time is 5×1
0.6 (N/m2).

As a typical value for a transformer with a capacity similar to that described above, it is assumed that the transposed conductor 2 consists of 19 rectangular wires of 7 mm x 2 mm, and the dimension L between the spacing pieces is 75 mm (the circumference of the spacing piece 41 is direction width dimension c = 25 mm), reinforcing insulator 31
The thickness dimension of is 2mm, therefore, vmax = 2mm
Then, the moment of inertia I of the dislocation conductor 2 is (2)
Obtained by substituting each value into the formula. I=(7×10-3)3 ・2×10-3・19/12
=1.09×10-9(m4)

Substituting these into equation (1) to find the force W and surface pressure σ required to bend the conductor 2 yields the following values. W=2×10-3・3・1.2×1011・1.09×
10-9/(75×10-3)3 =1.86×1
03 (N) σ=1.86×103 /{2.5×10-3・2×1
0-3・(19-1)/2} =4.13×106
(N/m2)

On the other hand, the surface pressure when pre-tightening the disc winding 100 is determined by factors such as the amount of drying shrinkage of insulators such as spacers and insulation coatings of conductors, and electromagnetic force generated by short-circuit accidents during operation of the transformer. is taken into account and 10×106 (N
/m2), it can be concluded that the bent portions 116A, 126A, and 136A are easily formed during the pre-tightening drying process.

[0029] The pretightening drying process is performed on the bent portions 116A,
Since 26A and 136A are formed, this bending process is not required during winding work, and the time required for winding work can be shortened.

[0030]

Effects of the Invention As described above, the present invention allows the conductor at the radial end of the disk coil to be connected to the conductor without bending the conductor with dimensions equivalent to the thickness of the reinforcing insulator during the winding work of the disk coil. By winding the wire while maintaining the gap between the spacer pieces, and then bending the conductor using the tightening force during the pre-tightening and drying process of the disk winding to close the gap, the bending process of the conductor during the winding work is made easier. A part of the wire is no longer required, and the winding time can be reduced by the amount of time required for the unnecessary bending process. Further, by providing a notch in the spacer piece corresponding to the axial movement dimension due to the clamping force of the conductor to which the reinforcing insulator is attached, an effect can be obtained that the bending dimension of the conductor can be made accurate.

[Brief explanation of drawings]

[Fig. 1] A sectional view of the main parts of a disc winding at the end of winding work, showing an embodiment of the present invention.

[Figure 2] B arrow view of the disc winding in Figure 1 after pre-tightening drying treatment

[Figure 3] Cross-sectional view of main parts of conventional disc winding

[Figure 4] Cross-sectional view of the dislocation conductor in Figure 3

[Figure 5] View from arrow A in Figure 4

[Explanation of symbols]

100 Disc winding 2 Dislocation conductor (conductor) 11 Disc coil 111 End conductor 112 Middle conductor 113 End conductor 115 Bending part 116 Bending part 116A Bending part 12 Disc coil 121 End conductor 122 Middle conductor 123 End conductor 125 Bending part 126 Bending part 126A Bending part 13 Disc coil 131 End conductor 132 Middle conductor 133 End conductor 135 Bending part 136 Bending part 136A Bending part 21 Wataribe 22 Watari part 23 Wataribe 31 Reinforcement insulation 32 Reinforcement insulation 33 Reinforcement insulation 41 Spacing piece 42 Spacing piece 43 Spacing piece

Claims (2)

[Claims] Claim 1: A coil made of insulating material in which a plurality of disc coils each having an insulated conductor stacked in the radial direction and wound in a plurality of turns are arranged in a predetermined equal number and equally spaced in the circumferential direction. Disc windings are stacked in the axial direction with spacing pieces in between, and the conductors at the radial ends of adjacent disc coils are alternately electrically connected to each other. The manufacturing method includes bending a conductor having a size corresponding to the thickness of a reinforcing insulator having an L-shaped cross section that insulates and reinforces the radial end conductor of the disc coil during winding work of the disc coil. First, a gap is maintained between the conductor and the spacing piece constituting the disk coil, and the conductor is bent by the axial tightening force during the pre-tightening drying process of this disk winding, and the gap is closed. A method of manufacturing a disc winding wire characterized by: 2. The method of manufacturing a disc winding according to claim 1, wherein the spacer piece is provided with a notch corresponding to the axial movement due to the clamping force of the conductor to which the reinforcing insulator is attached. .