JPH0314029Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to stationary induction equipment, and in particular, electrostatic plates are placed in parallel to the windings to improve the potential distribution and electric field distribution of the windings. This relates to stationary induction equipment such as transformers.

[Conventional technology]

The electrostatic plate installed in stationary induction equipment is placed outside the line end winding at the same potential as the terminal in order to improve the initial potential distribution against the shock voltage.
It is also effective in correcting the potential distribution in the line end windings and in mitigating the steep wave crest of the shock incoming wave due to the large ground capacity of the electrostatic plate.

As shown in FIG. 4, a conventional stationary induction device of this type has a main body consisting of a winding 1, an electrostatic plate 2, and an iron core 3, which is housed in a tank 5 equipped with a bushing 4. As shown in FIG. 5, it is connected to the high voltage winding group 1a and is disposed at the end of the high voltage winding group 1a. 1b is a low voltage winding group. Then,
The cross-sectional shape of the winding in a plane perpendicular to the conductor direction is vertically symmetrical with respect to the center line C, as shown in _{FIG .}
Then, t ₁ = t ₂ .

The electric field distribution near the electrostatic plate 2 is as follows:
As shown in the figure, when a 100% voltage is applied to the electrostatic plate 2 and a shared voltage is applied to the high voltage winding group 1a, an equipotential distribution shown by equipotential lines 6 is exhibited. That is, as shown in the figure, the equipotential line 6 near the electrostatic plate 2
The density is coarser at the upper end, which is at the same potential as the high-voltage winding group 1a, than at the lower end, and when the electric fields at the upper and lower ends are E ₁ and E ₂ , respectively, E ₁ < E ₂ . .

[Problem that the invention attempts to solve]

Conventional static induction devices such as those mentioned above use electrostatic plates with vertically symmetrical cross-sectional shapes, so the electric field at the top and bottom ends of the electrostatic plate becomes uneven, and the dimensions are reduced at the top end where the electric field is low. need to be large,
As a result, the winding group becomes longer, and the iron core 3 and tank 5 become larger and heavier, which is a problem.

This idea was made to solve these problems, and it uniformizes the electric field near the electrostatic plate,
The purpose of this invention is to obtain a stationary induction device that can be made smaller and lighter by reducing the length of the winding group.

[Means for solving problems]

The stationary induction device according to this invention includes an electrostatic plate whose cross-sectional shape in a plane perpendicular to the conductor direction of the winding is asymmetrical at both ends.

[Effect]

In this invention, the electric field strengths at the upper and lower ends of the electrostatic plate are approximately the same, and the electric field is uniform throughout the electrostatic plate.

〔Example〕

1 and 2 show an embodiment of this invention, in which an electrostatic plate 12 is shown in a plane perpendicular to the conductor direction of the winding.
As shown in Fig. 2, the cross-sectional shape is wedge-shaped with both ends asymmetrical with respect to the center line C, and here, the upper end has a thickness t ₃ and the lower end has a thickness t 3 that has the same potential as the winding group 1a. The relationship with ₄ is t ₃ < t ₄ .

As shown in FIG. 1, the electric field distribution near the electrostatic plate 12 is determined by making the thickness of the upper end of the electrostatic plate 12 thinner than that of the lower end. They are substantially the same, and if the electric field strengths at the upper and lower ends of the electrostatic plate 12 are E ₃ and E ₄ , then E ₃ 〓E ₄ .
This results in a uniform electric field throughout the electrostatic plate 12.

As described above, by making the upper end portion of the electrostatic plate 12 thinner, the length of the winding group 1a can be reduced by that amount. FIG. 3 is a diagram comparing the case a using the conventional electrostatic plate 2 and the case b using the electrostatic plate 12 of the above embodiment, with the dimensions of the high voltage winding group 1a being l ₁ and l ₂ respectively. Then, in b, the high voltage winding group 1a can be brought closer to the electrostatic plate 12 as a whole by the thinner upper end of the electrostatic plate 12, so l ₁ >
This shows that l ₂ . Accordingly, the device according to this invention can ultimately reduce the dimensions of the iron core 3 and the tank 5.

In the above embodiment, the electrostatic plate is placed at the end of the winding group, but the same effect can be obtained even if the electrostatic plate is placed in the middle of the winding group.

Furthermore, it goes without saying that the stationary induction device may be either an external iron type or an internal iron type.

[Effect of idea]

As is clear from the above explanation, this idea is
By using an electrostatic plate having an asymmetric cross-sectional shape at both ends, the dimensions of the winding group can be reduced, and the device can be made smaller and lighter.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of this invention,
FIG. 1 is an electric field distribution diagram, FIG. 2 is a sectional view of a main part, and FIG. 3 is a sectional view comparing dimensions. 4 to 7 show a conventional device, where FIG. 4 is a front sectional view, and FIG. 5 is a sectional view taken along the - line in FIG.
FIG. 6 is a sectional view of a main part, and FIG. 7 is an electric field distribution diagram. 1a... High voltage winding group (winding group), 12... Electrostatic plate. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] The stationary induction device includes a high-voltage winding group, a low-voltage winding group, and an electrostatic plate connected to and arranged at an end of the high-voltage winding group for improving the electric field of the high-voltage winding group. A stationary induction device comprising the wedge-shaped electrostatic plate in which the thickness of the end connected to the winding wire is thinner than the thickness of the other end.