JPS61222211A - Oil-filled stationary induction appliance - Google Patents

Abstract

PURPOSE:To reduce insulator dimensions, by constituting at least a portion of solid-state insulator by one having a specific inductivity approximately equal to or less than that of insulating oil, thereby to increase the voltage to be shared to the solid-state insulator which has a high dielectric strength. CONSTITUTION:There are provided a magnetic iron core 1 and one or more windings 2, 3 wound on the magnetic iron core 1. Solid-state insulator 4 and insulating oil 5 insulate electrically the respective windings 2, 3 from each other and the windings 2, 3 from the magnetic iron core 1. In such a stationary induction apparatus, at least a portion of the solid-state insulator 4 is constituted by one having a specific inductivity not more than that of the insulating oil 5. In general, in a gap between windings each having different voltage induced, each voltage shared to the respective constituting elements is determined in inversely proportion to the specific inductivity of the insulator. Accordingly, since the sharing voltage in the main insulator can be made larger for the solid-state insulator 4 having a higher dielectric strength as compared with the insulating oil 5, the thickness of the solid-state insulator 4 and therefore the thickness of the main insulator can be reduced, with the result that a transformer, etc., can be made small.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to anti-haze conductors such as transformers and reactors that are insulated by a composite insulator of a solid insulator and an insulating oil, and particularly relates to anti-haze conductors such as transformers and reactors. The present invention relates to an oil-filled stationary induction appliance having an insulation configuration suitable for reducing dimensions.

[Background of the invention]

Oil-filled stationary induction electric appliance 1 For example, the insulation configuration of a power transformer is 1
It is usually composed of composite insulation consisting of insulating paper and insulating oil. The dielectric constant of the insulating paper is higher than that of the insulating oil, and therefore, in this composite insulation structure, the electric field distribution is higher in the insulating oil, which has a lower dielectric constant.

Therefore, unless there is an abnormality in the insulating oil or insulating paper, dielectric breakdown will occur from the oil gap where the dielectric strength is low. For this reason, 1. Normally, in the insulation design of a transformer, a predetermined oil gap width is determined so as to increase the insulation strength of the insulation oil gap, and the insulation width dimension is determined thereby.

It has been difficult to achieve reductions in insulation dimensions and, in turn, reductions in static induction appliances.

As a structure to overcome this, Hitachi Review V o L,
65.

No. 5 (1983-5) - 3.3 Hybrid insulation is described in ``Technological Trends in Power Transformers'' published in pages 5 to 1. The data of each part is organized and integrated cross-sectionally, and the structure is created by combining the former subdivision method, which divides the oil gap with an insulating paper layer, and the filling insulation method, which fills the oil gap with a dielectric material. However, there is a limit to reducing the dimensions of the hybrid insulation, and it is difficult to reduce the dimensions of the static spinning conductor itself by reducing the dimensions of the hybrid insulation. Ta.

[Purpose of the invention]

An object of the present invention is to provide an oil-filled static-spun electrical conductor that eliminates the drawbacks of the prior art described above and allows the insulation dimensions of a composite insulation structure consisting of a solid insulator and an insulating oil to be reasonably reduced. There is a thing called K.

[Summary of the invention]

To achieve this object, the present invention provides, in a composite insulation configuration composed of a solid insulator and an insulating oil, at least a portion of the solid insulator having a specific conductivity equal to or equal to the peak of the specific conductivity of the insulating oil; It is characterized by being constructed of an insulator having a dielectric constant lower than that.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a typical two-winding transformer with terminals drawn out from both the upper and lower ends. magnetic iron core l
The main insulation is arranged between the low voltage winding 2 and the high voltage winding 3 which are arranged in K windings.

In the embodiment shown in FIG. 1, this main insulation is a three-layer solid insulator 4a.
, 4b, 4c, and oil gaps 5a to 5d formed between these solid insulators and between the solid insulator and each winding. 2a and 2b are the terminals of the low voltage winding 2, of which 2a is the line side terminal, and 3a and 3b are the terminals of the high voltage winding @3, of which 3a
6a, 6. indicate the line side terminals. b, 7a, and 7b are shield rings arranged at both upper and lower ends of the low-voltage winding, respectively. The voltage distribution of the low voltage winding 2 and the magnetic core 1, and the voltage distribution of the high voltage winding 3 and the magnetic core 1rIAK toward the solid L-shaped insulator is as shown in FIG.

That is, when the voltage distribution Eh of the high voltage winding 3 is the highest voltage El on the line terminal 3a side, and the voltage distribution Ej of the low voltage winding 2 is the highest voltage E on the line terminal 2a side, at the main insulation part,
The portion with the largest voltage share is the portion that shares the difference voltage s between the voltages E and E, that is, the line terminals 2a and 3.
The shared voltage for each component is determined in inverse proportion to the dielectric constant of the insulator constituting the winding a. In other words, in a portion composed of a plurality of insulating materials having different dielectric constants, the lower the dielectric constant, the larger the shared voltage becomes. Therefore, it is determined by the required insulation dimensions & strength, and the dielectric strength of the low dielectric constant material.

Now, when the main insulation configuration of FIG. 1 is modeled as shown in FIG. 3, the thickness of each solid insulator 4a to 4c is 4. The relative permittivity of these is 6.Is the thickness of the insulating oil gaps 5a to 5d. Their relative permittivity is -, the thickness of the main insulation, that is, the width between the high and low voltage windings is 10, and the total thickness of the solid insulator 4! ,. , the total thickness of the oil gap 5 is 140 s, and the differential voltage applied to the main insulation part is V.

1o 21g. Ten no. (1) Let the shared voltage of the solid insulator 4 be 1, and let the shared voltage of the insulating oil gap 5 be V.

v=v, +v, (2) Here,
As mentioned above, the shared voltage of each insulating component is determined in inverse proportion to the relative dielectric constant.

From equation (3) to equation (4), it is clear that C8≦e, that is, the relative dielectric constant of the solid insulator 4 is the ratio of the insulating oil gap 5. Usually, the main insulation dimensions of a transformer are The thickest round. Therefore, in this embodiment, at least the upper portions 4a to 4C of the solid insulators 4a to 4C located above the windings on the line terminal side are covered with a solid insulator 1 having a low dielectric constant, such as methylpentene,
An insulator made of a mixture of polymer fibers such as tetrafluoroethylene and pulp fibers at an excessive density is used.

Of course, the entire solid insulator 4 may be made of the above-mentioned mixed insulator.

Normally, the dielectric constant of insulating oil is 2.2 to 2.3, and the dielectric constant of presspod that constitutes the insulator is 3.5 to 4.
．． 5, the dielectric constant of the insulating material made of a mixture of polymer fibers such as methylpentene or tetrafluoroethylene and pulp fibers can be around 2.

Therefore, according to this embodiment, the voltage to be shared within the main insulation can be shared more to the solid insulator side, which has a higher dielectric strength than the insulating oil, so the thickness of the solid insulator can be reduced. The thickness or width of the main insulator can be reduced by this amount, and the transformer can be made smaller.

FIG. 4 shows an embodiment in which the present invention is applied to an upper and lower parallel winding structure in which the edge road side terminal 3a of the high voltage winding 30 is pulled out from the center of the winding 3.

In the winding configuration shown in FIG. 4, as shown in FIG. 5, the voltage distribution in the winding height direction is the maximum differential voltage E in the main insulation,
is located almost in the center, at least the solid insulators 4a to 4C- in the vicinity of the center of the main insulation are provided with a low specific electric constant insulator made of a mixture of polymer fibers and pulp fibers. be.

In the above embodiments, the present invention is applied to the main insulating part of a transformer, but the same effect can be obtained even if the present invention is applied to an L-shaped insulator interposed between the end of one winding and the iron core. Since this is something that can be obtained, detailed explanation thereof will be omitted.

In addition, reactors, which are oil-filled induction electric appliances other than transformers, P
Of course, the present invention can also be applied to insulation such as T and PCT.

〔Effect of the invention〕

As described above in detail using the embodiments.

According to the present invention, in a composite insulation configuration of a solid insulator and an oil gap, it is possible to increase the shared voltage on the solid insulator side with high insulation strength and reduce the insulation dimensions, thereby reducing the dimensions of electrical appliances. It is possible to provide an oil-filled, anti-rusting conductor.

[Brief explanation of the drawing]

1 and 4 are longitudinal sectional views of a transformer winding according to the present invention and its insulation configuration, FIG. 3 is a modeled view of the main insulation part, and FIGS. 2 and 5 are respectively the same as those shown in FIG. 1. 5 is a diagram showing the voltage distribution in the height direction of the transformer winding of FIG. 4. FIG. 1: Magnetic core, 2: Low-voltage winding, 3: High-voltage winding, 4: Solid insulator, 5: Insulating oil gap head agent Patent attorney Takeshi Kenjibu 731 No. 2-L- Figure 1 Figure 2 3rlA

Claims (1)

[Claims] 1. It has a magnetic core and at least one winding wound around the magnetic core, and a solid insulator and insulating oil are provided between the windings or between the windings and the magnetic core. 1. An oil-filled stationary induction appliance electrically insulated by an oil-filled stationary induction appliance, characterized in that at least a portion of the solid insulator is made of an insulator having a relative permittivity lower than the relative permittivity of the insulating oil. 2. In claim 1, the winding is composed of a high voltage winding, a medium voltage winding, and optionally a low voltage winding,
A plurality of solid insulating layers and an insulating oil layer are arranged between these windings to constitute main insulation, and at least the solid insulating layer located near the maximum voltage sharing between the windings is connected to the dielectric constant of the insulating oil layer. An oil-filled stationary induction electric appliance characterized by being constructed of an insulator having a relative permittivity of less than or equal to the dielectric constant. 3. It has a magnetic core and at least one winding wound around the magnetic core, and the windings are electrically insulated from each other or between the windings and the magnetic core using a solid insulator and insulating oil. An oil-filled stationary induction electric appliance, characterized in that at least a part of the solid insulator is made of an insulator having a dielectric constant substantially equal to the dielectric constant of the insulating oil.