JPH06267757A - Forced oil electrical machinery and apparatus - Google Patents

Abstract

PURPOSE:To prevent discharge due to fluidized charging in an oil gap between insulator layers in oil of a forced oil electrical machinery an apparatus. CONSTITUTION:An insulation material 18a whose resistivity is the same as that of an insulator in oil is attached adjacent to an in oil side of a rectangular surface formed in a contact part between insulators in oil 17 and 19. Therefore, D.C. electric field applied to an oil gap part 32 between insulator layers in oil is relaxed and discharged of insulation oil is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil feeding type electric device for forcibly circulating an insulating oil to cool an electric device body, and in particular, it is accumulated on the surface of an insulator used for a transformer, a reactor or the like. The present invention relates to an oil-conveying electric device suitable for preventing discharge due to electric charges.

[0002]

2. Description of the Related Art For example, a main body of an electric device such as a transformer or a reactor is mainly composed of an iron core and a winding wound around the core, and the winding is electrically insulated from an electric conductor. Have things. The electric device body is housed in a tank together with insulating oil, and the insulating oil is forcedly cooled by being circulated at high speed by an electric pump. A transformer having such a structure is disclosed in JP-A-51-137833.

[0003]

In the electric device constructed as described above, triboelectricity may be generated when the insulating oil comes into contact with and passes through the iron core and the winding of the electric device body. Electric charges may be accumulated on the surface of the oil and the insulator in the oil.

By the way, the distribution of the DC electric field generated by the electric charges generated by the frictional contact between the insulating oil and the main body of the electric device depends on the resistivity of the substance, and as shown in FIG. The electric potential lines 10 are concentrated and the electric field is increased.
On the insulating oil side, the electric field becomes lower because the resistivity of the oil is smaller than that of the insulating material in oil. Further, the DC electric field strength is large for the oil-insulated material and small for the insulating oil. In the actual structure, the contact portion of the in-oil insulator has a minute gap, and insulating oil exists in this minute gap 32. As shown in FIG. 3, since a DC electric field equivalent to that of the oil-in-insulator is applied to the oil in the minute gap 32, discharge or dielectric breakdown easily occurs at the contact portion of the oil-in-insulator.

The object of the present invention is to discharge or discharge the insulating oil in a minute gap existing in the contact portion between the oil-in-insulator and the oil-in-insulator due to a DC electric field generated by electric charge generated by frictional contact between the insulating oil and the main body of the electric device. It is to provide a structure capable of preventing dielectric breakdown.

[0006]

The feature of the present invention is that the resistivity is equivalent to that of the oil-in-insulator so that it is adjacent to the oil-inside of the oil-in-insulator of the right-angled surface formed at the contact portion of the oil-in-insulator. The point is that the insulating material is provided.

[0007]

With the above structure, the direct-current electric field applied to the insulating oil present at the contact portion of the oil-in-insulator is reduced, so that the discharge of the insulating oil can be prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings by taking a transformer as an example. In FIG. 1, 11 is a transformer tank,
The transformer body 12 and the insulating oil 22 are housed inside. The transformer body 12 is composed of an iron core 13 and high and low voltage windings 14, and is fixed to the transformer tank 11 by fixing an iron core tightening fitting 15 attached to the iron core 13 to a pedestal 16. Although not shown, the winding 14 of the transformer body 12 has insulating paper wound around the outer periphery thereof. The insulating oil flowing from the lower opening of the transformer tank 11 flows into the winding wire 14 through the openings 15a and 17a of the iron core tightening fitting 15 and the lower insulator 17, and also flows into the iron core 13 through the pedestal 16 to enter the transformer main body. Cool 12 This oil flow path is indicated by an arrow 50 in FIG. Between high and low voltage windings and high voltage winding 14
Insulators 19 and 20 arranged on the outer periphery of the coil, insulating paper wound on the outer periphery of the lead drawn from the upper and lower insulators 17 and the coil 14 disposed on both ends of the winding 14, and the like. It has an insulator in oil. In the present invention, in order to reduce the electric field value applied to the oil in the minute gap 32 in FIG. 2 in which the portion A of FIG. 1 is enlarged,
A triangular insulating material 18a having the same resistivity as the in-oil insulators 17 and 19 is attached to the in-oil insulator 17 and 19 on the right side of the contact surface between the oil-in-insulators 17 and 19. Insulator in oil 1 by insulating material 18
The equipotential line 10 to the oil gap 32 existing between 7 and 19
Is reduced and the electric field is lowered. Insulation 18
The same effect as the structure of the triangular insulating material of the present invention can be obtained even if it is not triangular as long as it has a shape that contacts the in-oil insulators 17 and 19.

The present invention has the same effect in a DC electric device used in a DC power transmission system. The same applies to self-cooling DC electric devices that are not forcibly cooled.

[0010]

According to the present invention, since the direct current electric field can be reduced because the concentration of equipotential lines in the minute oil gaps on the contact surfaces of the insulators is alleviated, the insulating oil in the minute oil gaps can be reduced. It is possible to prevent discharge or dielectric breakdown.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a transformer body.

FIG. 2 is an enlarged view of part A of FIG. 1 showing an embodiment of the present invention.

FIG. 3 is an explanatory view of a conventional structure corresponding to FIG. 2.

[Explanation of reference numerals] 10 ... equipotential lines, 13 ... iron core, 14 ... windings, 17, 19
... Insulator in oil, 18a, 18b ... Insulating material, 22 ... Insulating oil, 32 ... Minute gap between insulators in oil.

Claims (3)

[Claims] 1. A main body of an electric device including an iron core, a winding wound around the iron core, and an insulator electrically insulating the winding is housed in an electric device tank together with insulating oil, and the insulating oil is stored. In a device that circulates to forcibly cool the main body of the electric device, a resistivity equivalent to that of the insulator is provided so as to be adjacent to the oil-side of a right-angled surface formed at the contact portion of the insulator and the insulator. An oil-feeding electric device characterized by being provided with an insulating material. 2. The oil feeding type electric device according to claim 1, wherein the insulating material is formed in a triangular shape. 3. A self-cooling type DC electric device having the structure of claim 2.