JP3344531B2 - Support structure for stationary induction winding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winding supporting structure for clamping a winding of a gas-insulated transformer or reactor from both ends thereof, and more particularly to a winding supporting structure in which an electric field at a winding end is reduced. Regarding the structure.

[0002]

2. Description of the Related Art An insulated flat copper wire is wound in a disk shape around a stationary induction coil wound in an insulating gas, and the disk is stacked in layers in the axial direction. There is a winding or a cylindrical winding formed by winding an aluminum foil together with a plastic film (for example, polyethylene terephthalate) to form a cylindrical shape. As the insulating gas, SF ₆ gas having a high withstand voltage is used, and the stationary induction device winding is supported by a supporting insulator in the insulating gas in the closed tank.

FIG. 5 is a cross-sectional view showing a conventional structure for supporting a stationary induction winding. The stationary induction winding is the primary winding 4
And a secondary winding 5 around which the main leg 3 of the iron core 1 is wound. Further, an iron frame 6 sandwiches the iron core 1 from both sides, and also sandwiches the primary winding 4 and the secondary winding 5. Further, between the primary winding 4 and the frame 6, a supporting insulator 12 in the form of a square block is interposed. In addition, the primary winding 4 and the secondary winding 5 are also arranged on the near side and the depth side in FIG. The iron core 1 includes horizontal yoke 2 above and below a main leg 3, and the main legs 3 of each phase are magnetically joined. The entire apparatus of FIG. 5 is housed in a sealed tank filled with SF ₆ gas.

FIG. 6 is a sectional view taken along the line EE of FIG. Three sets of primary windings 4 and secondary windings 5 that wind the main leg 3 are arranged side by side, and FIG. 6 shows only those of the central phase. The configuration of the bilateral phase is the same as that of the central phase. The frame 6 does not appear in the cross-sectional view of FIG. 6, but is indicated by a dotted line. The frame 6 is an L-shaped channel, and sandwiches the iron core from both sides. Square block-shaped supporting insulators 12 and 13 are vertically arranged at the place where the frame 6 is disposed.
The primary winding 4 and the secondary winding 5 are fastened one by one. The support insulator 13 is interposed between the secondary winding 5 and the frame 6, and has the same configuration as the support insulator 12 in FIG. 6 corresponds to FIG. 5. Support insulators 12, 13
For example, FRP (glass fiber reinforced plastic fiber-glass resin
inforced plastic) or press-formed P
B (press board) is used.

[0005]

However, the conventional structure as described above has a problem that the electric field at the end of the winding tends to concentrate. Generally, when a solid insulator is interposed in gas insulation, an electric field concentrates on an insulating gas portion. This is because the relative permittivity ε of the insulating gas is 1, while the relative permittivity ε of the solid insulator is always 1 or more, so that the burden voltage on the insulating gas portion increases. Also in the above-described support structure for the stationary induction winding, a solid insulator called a support insulator is interposed in the insulating gas. The relative dielectric constant ε of the supporting insulator is 3.5 for PB and 5 for FRP. For this reason, the dielectric strength of the winding supporting structure is almost always determined at the position where the supporting insulator is provided. If a solid insulator having a small relative dielectric constant ε is used as the supporting insulator, the dielectric strength of the winding supporting structure is improved. However, since the supporting insulator supports the winding, it must be mechanically strong and withstand the heat of the winding. Solid insulators having excellent mechanical properties and heat resistance properties and a small relative dielectric constant ε are not commonly found. Therefore, conventionally, the electric field at the ends of the windings has been reduced by increasing the insulation dimension between the windings and the frame. For this reason, the stationary induction device as a whole has also become large and costly.

SUMMARY OF THE INVENTION It is an object of the present invention to use a conventional material as a solid insulator to further reduce the electric field at the end of the winding, and to reduce the insulation size in the support structure for the stationary induction winding.

[0007]

According to the present invention, in order to attain the above object, according to the present invention, both ends in the axial direction of a stationary induction winding wound in an insulating gas are supported on a frame for fastening an iron core. In the supporting structure of the stationary induction electric coil winding sandwiched through, the supporting insulator has a configuration in which a first insulating plate and a second insulating plate are arranged on both end surfaces of the insulating cylinder, respectively, and the first insulating plate is stationary. In addition to being provided on the induction winding,
Preferably, the second insulating plate is provided on the frame side.

Alternatively, in such a support structure for a stationary induction winding, the first insulating plate may have a smaller dielectric constant than that of the second insulating plate. Alternatively, in the support structure of the stationary induction device winding, an insulating brim portion facing the stationary induction device winding side is disposed at both ends of the first insulating plate to form a U-shaped insulator, and this insulation is provided. The U-shaped part of the body may be fitted to the end of the stationary induction winding.

According to the structure of the present invention, the supporting insulator has a structure in which the first insulating plate and the second insulating plate are disposed on both end surfaces of the insulating cylinder, respectively. The first insulating plate is provided on the stationary induction device winding side, and the second insulating plate is provided on the frame side. Conventionally, a square block-shaped supporting insulator filled with a solid insulator has been used. Since the inside of the insulating cylinder is an air core, the insulating gas has the smallest relative dielectric constant ε. Therefore, even if a conventional material is used as the solid insulator, the electric field at the end of the winding becomes very low. In addition, since the insulating cylinder is mechanically strong against the axial force even in shape, it sufficiently fulfills the role of a supporting insulator.

The first insulating plate has a lower dielectric constant than that of the second insulating plate. Generally, the electric field distribution between the stationary induction winding and the frame is such that the closer to the end of the winding, the higher the electric field. For this reason, if the relative dielectric constant ε of the first insulating plate near the winding end is reduced as much as possible, the voltage borne by the first insulating plate itself increases, and accordingly, the voltage is closer to the winding end. The burden voltage on the insulating gas portion is reduced. Generally, the dielectric strength of the solid insulator itself is two to three orders of magnitude higher than that of the insulating gas. Therefore, even if the electric field in the solid insulator such as the first insulating plate is slightly increased, there is no problem in practical use. Since the electric field in the insulating gas near the winding end decreases, the withstand voltage of the winding support structure improves,
The insulation size can be further reduced. On the other hand, the electric field near the frame side is very low. Therefore, even if the relative dielectric constant ε of the second insulating plate is somewhat large, the electric field around the second insulating plate is originally low, so that the second insulating plate does not bear any voltage. Therefore, even if the second insulating plate has a higher relative dielectric constant than that of the first insulating plate, the dielectric strength of the winding supporting structure is hardly affected.

[0011] Further, an insulating brim portion facing the stationary induction device winding side is arranged at both ends of the first insulating plate to form a U-shaped insulator. The U-shaped part of the insulator is fitted to the end of the stationary induction winding. As a result, the end of the stationary induction winding is engaged with the supporting insulator, and the stationary induction winding is mechanically resistant to vibration in the radial direction.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 is a cross-sectional view showing a support structure of a stationary induction winding according to an embodiment of the present invention. The supporting insulator 8 includes an insulating tube 10 and a first insulating plate 9A and a second insulating plate 9B disposed on both end surfaces of the insulating tube 10, respectively. The first insulating plate 9A is provided on the primary winding 4 side, and the second insulating plate 9B is provided on the frame 6 side. Except for the configuration of the supporting insulator 8, the configuration is the same as the conventional configuration in FIG. The same parts as those in the related art are denoted by the same reference numerals, and detailed description thereof will not be repeated here.

FIG. 2 is a sectional view taken along line AA of FIG. Insulating cylinders 10 and 11 made of a supporting insulator are interposed at upper and lower positions where the frame 6 is disposed, and the primary winding 4 and the secondary winding 5 are fastened. The rest is the same as the conventional configuration of FIG. The insulating cylinder 11 has the same configuration as the supporting insulator 8 in FIG. 1, and both ends thereof are sandwiched between a first insulating plate and a second insulating plate. In addition, the BB cross section of FIG. 2 corresponds to FIG.

In FIG. 1, an insulating cylinder 10 of a supporting insulator 8 is provided.
Is an air core and is an insulating gas having the smallest relative dielectric constant ε. FIG. 7 is an electric field distribution diagram in the configuration of FIG. In the calculation of FIG. 7, the potential is 100% for the inner surface 4A of the primary winding 4, the outer surface 4B of the primary winding 4, and the secondary winding 5.
, The right side surface 14 of the iron core, the lower surface 15 of the upper frame, and the inner wall 16 of the closed tank are 0%. The relative permittivity ε is
The insulating cylinder 10 is 5 as FRP, the first insulating plate 9A is 2.5 as polyamide paper, the second insulating plate 9B is 3.5 as PB,
The insulating gas 22 is 1. In FIG. 7, the calculated equipotential lines 20 are shown at a 20% pitch. On the other hand, FIG.
6 is an electric field distribution diagram in the conventional configuration of FIG. FIG.
In the calculation of, the potential is the same as in the case of FIG. The relative dielectric constant ε is set to 5 for the supporting insulator 12 as FRP and 1 for the insulating gas 22. The calculated equipotential line is the solid line 21 and is shown at a 20% pitch. The dotted line in the figure is the equipotential line 20 calculated in FIG.

As can be seen from FIGS. 7 and 8, the equipotential line 20 moves away from the primary winding 4 by interposing the insulating cylinder 10 in the supporting insulator, and the electric field at the end of the winding is reduced. According to the calculation, the maximum electric field at the winding end in FIG.
20% less than that of The primary winding 4
The size of insulation between the frame and the frame can be reduced. In FIG. 7, the first insulating plate 9A and the second insulating plate 9B
Has the effect of relaxing the electric field even if an insulating material having the same relative permittivity ε is used, but it is better to make the relative permittivity ε of the first insulating plate 9A smaller than that of the second insulating plate 9B. This is because, as can be seen from the electric field distribution in FIG. 7, the electric field increases as the electric field distribution between the primary winding 4 and the frame approaches the end of the primary winding 4. If the relative dielectric constant ε of the first insulating plate 9A near the winding end is made as small as possible, the voltage borne by the first insulating plate 9A itself becomes large, and the portion close to the winding end is correspondingly increased. Of the insulating gas 22 is reduced. In the case of FIG. 7, the relative dielectric constant ε of the first insulating plate 9A is 2.
5. The relative dielectric constant ε of the second insulating plate 9B is 3.5, which is smaller in the former. First insulating plate 9A and second insulating plate 9
The electric field is relaxed by 5% as compared with the case where the relative dielectric constant ε with B is 3.5.

On the other hand, as can be seen from FIG. 7, the electric field near the frame side is very low. For this reason, even if the relative dielectric constant ε of the second insulating plate 9A is somewhat large, the surrounding insulating electric field is originally low, so that the second insulating plate 9B does not bear any voltage. Therefore, even if the second insulating plate 9B has a higher relative dielectric constant ε than that of the first insulating plate 9A, it hardly affects the dielectric strength of the winding supporting structure.

As a matter of course, it is preferable that the relative permittivity ε of the insulating cylinder 10 is as small as possible. However, this insulating tube 1
Since a zero force is applied in the axial direction, the material must be mechanically robust and its choice is naturally limited. Therefore, a relatively large relative permittivity ε such as FRP
It must be composed of The electric field in the insulating gas 22 is reduced by making the thickness of the insulating cylinder 10 as small as possible within a mechanically allowable range. Therefore, the insulating cylinder 1
FRP with excellent mechanical properties is adopted as the material of No. 0,
The gap in the insulating tube 10 is as large as possible.

Further, the first insulating plate 9A and the second insulating plate 9B
In the absence of the above, the electric field in the insulating gas 22 may be reduced.
However, these insulating plates 9A and 9B are necessary to be received on the surfaces of the windings 4 and 5 and the frame 6, and provide mechanical protection for the windings 4 and 5 and the insulating cylinder 10. Therefore, the first insulating plate 9A and the second insulating plate 9B cannot be eliminated, but the electric field in the insulating gas 22 becomes lower when these insulating plates are made as thin as possible.

FIG. 3 is a sectional view showing a supporting structure for a stationary induction winding according to another embodiment of the present invention. The first insulating plate 9A of the supporting insulator 80 has insulating flanges 7 at both ends thereof, and is formed on the U-shaped insulator 23. The end of the primary winding 4 is fitted into the U-shaped portion of the insulator 23. Others are the same as the configuration of FIG. FIG. 4 is a cross-sectional view taken along line CC of FIG.
The cross section corresponds to FIG. In FIG. 3, the end of the primary winding 4 and the supporting insulator 80 are firmly engaged with each other by the collar portion 7. This makes the primary winding 4 mechanically robust against radial vibrations and improves winding reliability. The collar portion 7 may be formed by bending the material of the first insulating plate 9A, and it is needless to say that the relative dielectric constant ε should be as small as possible.

[0020]

As described above, the present invention has a structure in which the supporting insulator is provided with the first insulating plate and the second insulating plate on both end surfaces of the insulating cylinder, respectively. The first insulating plate is provided on the stationary induction device winding side, and the second insulating plate is provided on the frame side. As a result, the electric field at the end of the winding is reduced by 20% as compared with the conventional configuration, and the insulation size of the winding supporting structure can be reduced. Therefore, the entire stationary induction device is also reduced in size, and its cost is reduced.

The first insulating plate has a lower dielectric constant than that of the second insulating plate. This further lowers the electric field at the winding ends and further reduces the insulation dimensions of the winding support structure. In addition, an insulating brim portion facing the stationary induction device winding side is arranged at both ends of the first insulating plate to form a U-shaped insulator. The U-shaped part of the insulator is fitted to the end of the stationary induction winding. As a result, the stationary induction winding is made mechanically strong, and the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a support structure for a stationary induction motor winding according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a cross-sectional view showing a support structure of a stationary induction winding according to another embodiment of the present invention;

FIG. 4 is a sectional view taken along the line CC of FIG. 3;

FIG. 5 is a sectional view showing a conventional stationary induction device winding support structure.

FIG. 6 is a sectional view taken along line EE of FIG. 5;

FIG. 7 is an electric field distribution diagram in the configuration of FIG.

8 is an electric field distribution diagram in the configuration of FIG.

[Explanation of symbols]

1: Iron core, 2: Yoke, 3: Main leg, 4: Primary winding, 5: Secondary winding, 6: Frame, 7: Collar, 8, 80: Support insulator, 9A: First insulating plate , 9B: second insulating plate, 10, 1
1: insulating tube, 23: insulator

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 27/30 H01F 30/12

Claims (3)

(57) [Claims] 1. A supporting structure for a stationary induction electric winding, wherein both end faces in the axial direction of the stationary induction electric winding disposed in the insulating gas are sandwiched by a frame for fastening an iron core via a supporting insulator. The object has a configuration in which a first insulating plate and a second insulating plate are respectively disposed on both end surfaces of the insulating cylinder, and the first insulating plate is provided on the stationary induction machine winding side, and the second insulating plate is provided on the frame side. A support structure for a stationary induction winding, wherein the support structure is provided. 2. The static induction motor winding support structure according to claim 1, wherein the first insulating plate has a lower dielectric constant than that of the second insulating plate. Support structure. 3. A supporting structure for a static induction electric machine winding according to claim 1, wherein an insulating flange portion facing the static induction electric winding side is provided at both ends of the first insulating plate. A stationary induction motor winding supporting structure, wherein a U-shaped insulator is formed and a U-shaped portion of the insulator is fitted to an end of the static induction motor winding.