JPH0782947B2 - Oil-filled induction winding - Google Patents

Description

TECHNICAL FIELD The present invention relates to an oil-filled induction winding having a coil surface and a linear spacer forming a first oil gap.

[Conventional technology]

Generally, in an inner iron type transformer, as shown in FIG. 5, a low voltage winding 4 formed by stacking a number of donut-shaped coils is arranged around an iron core leg 1, and a main insulation dimension L ₁ is secured from this. ,
Similarly, the high voltage winding 3 formed by stacking a large number of donut-shaped coils is concentrically arranged. 2 is a tank, 15 is a tank wall, and 16 is a winding end insulating material. FIG. 6 shows the detailed structure of the A part of the winding.

The insulation of the windings is maintained by the insulation between the high voltage winding 3 and the low voltage winding 4, the so-called main insulation dimension L ₁ and the coil insulation dimension L ₂ . The main insulating portion is composed of insulating barriers 8 and 11 and linear spacers 7 and 12, and the oil gap is subdivided to maintain insulation. The insulating barrier 8 is used to prevent the progress of the discharge when the discharge is started from the winding. Further, the linear spacer 7 forming the first oil gap 6 has a structure in which the inter-coil spacer 9 can be fitted.

On the other hand, the inter-coil insulation is constituted by the coil insulation coating 13 and the inter-coil spacer 9, and the insulation is held by the oil gap 10.
The insulating barriers 8 and 11, the linear spacers 7 and 12, and the inter-coil spacer 9 are all made of pressboard made of pulp, and their relative permittivity is 4.8, which is larger than 2.2 of oil.

[Problems to be Solved by the Invention]

As is apparent from FIG. 6, the main insulation and the inter-coil insulation affect the size of the winding, and if the insulation dimensions can be reduced, the size can be greatly reduced. FIG. 7 shows a dielectric breakdown path due to a lightning impulse in the conventional structure shown in FIG. The high electric field portion is a portion B of the inner-diameter side coil corner portion showing a combined electric field due to the winding difference voltage and the coil difference voltage.

Many model experiments have been conducted so far, but there is nothing that causes dielectric breakdown from the oil gap 10 on the coil surface at the same part.
In both cases, the breakdown occurs from the wedge-shaped oil gap in the portion in contact with the linear spacer 7 or the inter-coil spacer 9, leading to the main insulation creep breakdown E or the inter-coil insulation breakdown F.

FIG. 8 shows the result of microscopic electric field analysis of this phenomenon using the coil 5 and the inter-coil spacer 9 as an example. Since the insulating coating 13 of the coil is formed by winding thin kraft paper, its relative permittivity is 3.5, the relative permittivity of oil is 2.2, and the inter-coil spacer 9 is a press board made of pulp, so the relative permittivity is The rate is 4.8.

As described above, since the relative permittivities are greatly different, a high electric field is generated in the minute oil gap C formed by the coil 5 and the inter-coil spacer 9, and this portion becomes the starting point of the dielectric breakdown, and the linear spacer 7
Also, the insulation strength without the inter-coil spacer 9 is greatly reduced. Therefore, by alleviating the electric field of the minute oil gap, it is possible to significantly improve the dielectric strength, and it is possible to achieve miniaturization by reducing the insulation dimension.

An object of the present invention is to solve the above problems in the conventional technique and to provide an oil-filled induction winding capable of improving the dielectric strength between the first oil gap and the coil.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a winding formed by stacking a large number of donut-shaped coils around which insulating paper is wound,
In an oil-filled induction winding with a leading edge barrier arranged around the winding for insulation and insulating oil cooling passage configuration, every other dielectric constant of the insulating oil between adjacent coils. It is characterized in that a mixed press board having a dielectric constant closer to is arranged so as to extend from the inner end to the outer end in the radial direction of the coil.

[Action]

Since the present invention is configured as described above, electric field concentration of minute oil gaps between the coils due to a difference in relative permittivity is mitigated, and the dielectric strength between the coils can be improved.

[Examples] Hereinafter, the present invention will be described based on illustrated examples.

1 (a) and 1 (b) are winding layout diagrams, and FIG. 1 (c) is a winding structure diagram according to the first embodiment of the present invention. The winding structure shown in FIG. 1 (c) is an enlarged view of the disk winding D near the line ends of the upper and lower parallel windings or the winding winding 14 shown in FIGS. 1 (a) and (b). Is. In each figure, the same or equivalent parts as those in FIGS. 6 and 7 are designated by the same reference numerals. The linear spacer 7 is not shown in FIG. 1 (c).
Numeral 20 is an inter-coil spacer which is arranged between every two adjacent coils. Unlike the conventional inter-coil spacer 9, the inter-coil spacer 20 is made of a low-dielectric-constant insulating material made by mixing polyethylene terephthalate fiber and pulp, that is, a low-dielectric-constant mixed press board. The relative permittivity of this low-permittivity mixed press board is 3.5, which is the same as the relative permittivity of the insulation coating of each coil of the disk winding, which is much higher than that of conventional pressboards. Close to the rate,
It also has excellent heat resistance, oil resistance, and workability.

The voltage difference between the coils and the voltage difference between the shields 17 are large in the twin coil 10a, and the electric field at the corner portions of the wire wires 11 and 30 (31, 50) facing each other and the electric field on the opposing surface of the shield 17 are high. Become. In the present embodiment, between the twin coils 10
The inter-coil spacer 20 of the low dielectric constant mixed press board which fits with the linear spacer 7 is arranged in a.

As described above, in this embodiment, since the inter-coil spacer of the low dielectric constant mixed press board is arranged between the twin coils, the electric field concentration of the minute oil gap due to the difference in the dielectric constant is further improved as compared with the conventional press board. It can be relaxed to improve the dielectric strength, and it is possible to reduce the size and weight and reduce the loss. Also, since the inter-coil spacers of the low dielectric constant mixed press board are arranged every other space between the adjacent coils, the amount of the expensive low dielectric constant mixed press board used can be reduced.

FIG. 2 is a winding structure diagram according to the second embodiment of the present invention. In this figure, the same or equivalent parts as those shown in FIG. 1 (c) are designated by the same reference numerals. This winding structure shows an interleaved winding, in which inter-coil spacers 20 of the above low dielectric constant mixed press board which are fitted with linear spacers 7 are arranged between units 10b having a large inter-coil differential voltage between coils. is there. The effect of this embodiment is the same as the effect of the previous embodiment.

FIG. 3 is a winding structure diagram according to a third embodiment of the present invention, in which the same or equivalent parts as those shown in FIG. 2 are designated by the same reference numerals. In the present embodiment, the corner insulating ring 21 and the insulating barrier 22 of the low dielectric constant mixed pressboard are arranged between the units 10b having a large inter-coil winding voltage difference between the units in order to reduce the electric field and improve the dielectric strength. is there. Further, the lower winding 23 of the low dielectric constant material is arranged for adjusting the electric field. The effect of this embodiment is the same as the effect of the previous embodiment.

FIG. 4A is a winding layout diagram, and FIG. 4B is a winding structure diagram according to the fourth embodiment of the present invention. Winding shown in Fig. 4 (a)
Reference numeral 14 indicates a winding medium-pressure disk winding. Figure 4 (b) shows the fourth
It is the figure which expanded the part D of the intermediate-pressure disk winding 14 shown in FIG. In FIG. 4 (b), the same or equivalent parts as in FIG. 1 (c) are designated by the same reference numerals. Reference numeral 24 is an upper coil for adjusting the electric field, which is arranged so as to face the end of the high voltage line, and uses a low dielectric constant material. Also in this embodiment, the inter-coil spacer 20 of the low dielectric constant mixed press board is arranged between the coils 10c where the inter-coil differential voltage is generated. The effect of this embodiment is the same as the effect of the previous embodiment.

〔The invention's effect〕

As described above, according to the present invention, there is one gap between adjacent coils.
Since a low-dielectric-constant mixed press board was placed every other side from the radial inner end to the outer end of the coil, the electric field at the beginning of the discharge can be relaxed to improve the dielectric strength. It is possible to reduce the size, weight and loss. Further, since the low dielectric constant mixed press board is arranged every other coil between the adjacent coils, it is possible to reduce the amount of expensive low dielectric constant mixed press board used.

[Brief description of drawings]

1 (a) and 1 (b) are winding layout diagrams, FIG. 1 (c) is a winding structure diagram according to the first embodiment of the present invention, and FIG. 2 is a second embodiment of the present invention.
Fig. 3 is a winding structure diagram according to the embodiment of the present invention, Fig. 3 is a winding structure diagram according to the third embodiment of the present invention, and Fig. 4 (a) is a winding arrangement diagram.
FIG. 5B is a winding structure diagram according to the fourth embodiment of the present invention, and FIG.
FIG. 6 is a perspective view showing a main part of a conventional oil-filled induction winding.
FIG. 7 is an enlarged view of an essential part of FIG. 5, FIG. 7 is a perspective view of an essential part showing a dielectric breakdown path, and FIG. 8 is a potential mapping diagram of the essential part of FIG. 3 ... High-voltage winding, 4 ... Low-voltage winding, 6 ... First oil gap, 8
…, Insulation barrier, 20 …… Spacer between coils of low dielectric constant mixed press board, 21 …… Corner insulation ring of low dielectric constant mixed press board, 22 …… Insulation barrier of low dielectric constant mixed press board, 23 …… Lower volume , 24 …… Volume 1.

Claims (1)

[Claims] 1. A winding comprising a plurality of doughnut-shaped coils laminated with insulating paper, and an insulating barrier disposed around the winding for the purpose of forming a cooling passage for insulating oil and insulating oil. In the oil-filled induction winding, the mixed paper press board having a dielectric constant closer to that of insulating oil is provided between the adjacent coils to extend from the inner end to the outer end in the radial direction of the coil. An oil-filled induction electric wire winding characterized by being arranged.