JPH0424909A - Electromagnetic induction apparatus - Google Patents

Abstract

PURPOSE:To make temperature distribution in winding uniform by making the cross section of each wire material vary along the Length direction of the wire material according to the temperature distribution of a cooling medium. CONSTITUTION:Although winding 3 indicates only a wound layer, each wire material 4 increases its cross section gradually as the wire material is wound upward. Then the wire material 4 makes the cross section vary in the direction of length continuously or stepwise and winding 3 is made up by performing winding of a Prescribed number of turns. As the wire material makes the cross section larger as it is wound upward, the heating density of wire materials decreases as they are wound upward even though the same electric current flows. In this way, the inclined characteristics of local temperature distribution that increases as air 5 cooling the wire materials 4 flows upward offset the inclined characteristics of heating density distribution and the compensation of both characteristics makes the vertical temperature distribution of the wire materials 4 almost uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electromagnetic induction equipment such as transformers, and particularly to equipment with improved cooling performance.

[Problems to be solved by conventional technology and invention] Part 3
The figure is a diagram showing the schematic structure of a conventional transformer of this type and the temperature distribution of the winding. In the same figure (A), (1) is an iron core, and the vertical part forms the iron core leg [2] around which the later-described winding (3) is wound. The winding (3) is, for example, described in "° Transformer Design and Construction Method" P. 5, published by Denkishoin August 1960.
As shown in 7 to 59, a wire rod 4 made of a rectangular wire (or round wire) whose cross-sectional area is constant is wound a predetermined number of times in the vertical direction and in a predetermined number of layers in the radial direction. It is made up of.

The iron core (1) and the winding (31) are housed in a container (not shown) together with air (51) as a cooling medium.

Next, the cooling performance of this transformer, particularly the temperature distribution within the winding (3), will be explained. Figure 3 (B) shows, for example, winding (3)
This figure shows the temperature distribution along the height direction of the outermost wound layer of the wire rod, and the temperature of the wire rod field increases as it goes upward. This is because the cross-sectional area of the wire (A) is uniform, so the heat distribution is almost uniform; however, these wires (2)
This is due to the influence of the local temperature distribution of the air (51) that contacts and cools the winding (3).In other words, a relatively cold air raid (5) is supplied from below the winding (3), As these air ((5) rises along the wire (a),
The temperature of the wire (A) gradually increases by absorbing the heat generated from the wire (A). Therefore, the temperature of the air (9) that comes into contact with the wire (2) in the upper position increases (the temperature of the air that contacts the wire (2) in the lower position
5], and as a result, a temperature gradient as shown in the figure occurs in the wire (2) that is cooled using this air (9) as a cooling medium.

Figure 3 (C) shows the temperature distribution in the radial direction of the upper end portion of the winding (3), that is, in the direction of the winding layer. As a result, the temperature of the wire (2) is high.

Electrical equipment such as transformers are designed to be cooled so that the maximum operating temperature of the insulating material is below an allowable value. There is a large temperature difference between wires (3), and it is necessary to keep the temperature at the highest point below the allowable value. There was also the problem of being inferior in gender.

This invention was made in order to solve the above-mentioned problems, and aims to equalize the temperature distribution within the winding.

[Means and effects for solving the problem] The electromagnetic induction device according to the present invention changes the cross-sectional area of the wire in the length direction according to the local temperature distribution of the cooling medium that comes into contact with the wire. This is what I did.

The cross-sectional area of the wire in the part where the temperature of the cooling medium is high is increased to reduce its heat generation density, and conversely, the cross-sectional area of the wire in the part where the temperature of the cooling medium is low is decreased to increase its heat generation density, and the overall Make the temperature distribution of the wire uniform.

By increasing the cross-sectional area of the wire as it goes upward in the vertical direction of the winding, the temperature difference in the vertical direction of the winding can be suppressed, especially when the winding is cooled by natural convection of the cooling medium.

Further, by increasing the cross-sectional area of the wire as it goes inward in the radial direction of the winding, the temperature difference in the radial direction of the winding can be suppressed.

〔Example〕

FIG. 1 is a diagram showing the schematic structure and temperature distribution of the windings of a transformer according to an embodiment of the present invention. In addition, here,
Volume 1! (3) shows only one winding layer. The same figure (A
), the cross-sectional area of the wire (A) gradually increases as it goes upward. That is, the wire 4 has a cross-sectional area that changes continuously or stepwise in the length direction, and is wound a predetermined number of times to form a winding (3).

In this case, the cross-sectional area of the wire (2) increases as it moves upward, so even if the same current flows, its heat generation density decreases as it moves upward. As a result, the air that cools these wires 4 (the slope characteristic of the local temperature distribution that increases as it goes upward) and the slope characteristic of the heat generation density distribution described above cancel each other out, as shown in Figure (B). , wire rod (a)
The temperature distribution in the vertical direction becomes almost uniform.

Figure 2 shows another embodiment, in which winding (3)
The aim is to improve the temperature distribution in the radial direction of the winding layer, and thus in the direction of the wound layer. That is, the innermost layer wire (2) has the largest cross-sectional area, and the wire rod (4) is arranged so that the cross-sectional area decreases as it goes to the outer layer.
) is changing the cross-sectional area in the longitudinal direction.

As explained in the conventional technology, the cooling conditions in the vicinity of the iron core leg (21) tend to be poor and the temperature of this part tends to rise. By increasing the temperature, the heat generation density is reduced, and the temperature distribution in the radial direction becomes almost uniform by offsetting the above-mentioned tendency of the cooling conditions (FIG. 2(B)).

As described above, it is possible to equalize the temperature distribution within the winding (3). For example, if the winding temperature of the device according to the present invention is set to the same value as the conventional maximum temperature, the amount of wire material can be significantly reduced. This makes it possible to reduce the amount of water and improve the economic efficiency of the product. Also,
If the amount of wire is the same as before, the maximum temperature will be lowered due to uniform temperature distribution, the thermal life of the insulator will be correspondingly increased, and the reliability of the product will be improved.

In each of the above embodiments, a case has been described in which one wire rod (2) is wound to form the winding wire (3), but a plurality of wire rods may be wound.

In addition, in each of the above embodiments, a so-called self-cooling type natural convection circulation cooling method using air (51) as the cooling medium has been described, but a so-called forced circulation air cooling type using a fan or the like or an insulated cooling medium This invention can be similarly applied to those using oil, and the same effect can be achieved.In the case of forced circulation air cooling, the wind temperature generally increases as you go downwind, so the cross-sectional area of the wire also increases. Increase the size according to the direction.

Furthermore, if the cross-sectional area of the wire is changed by considering both the temperature distribution in the vertical direction of the winding shown in Fig. 1 and the radial direction of the winding shown in Fig. 2, the temperature distribution inside the winding can be improved. This results in further improvement in uniformity.

〔Effect of the invention〕

As described above, in this invention, the cross-sectional area of the wire is changed along the length of the wire according to the temperature distribution of the cooling medium. ! , the density becomes a value commensurate with the cooling conditions, and as a result, the temperature distribution within the winding becomes uniform.

Furthermore, by increasing the cross-sectional area of the wire as it goes upward in the vertical direction of the winding, the temperature difference in the vertical direction of the winding can be suppressed, especially in the case of natural convection cooling.

Furthermore, by increasing the cross-sectional area of the wire as it goes inward in the radial direction of the winding, the temperature difference in the radial direction of the winding is suppressed.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams showing the schematic structure and temperature distribution of the windings of a transformer according to an embodiment of the present invention, respectively, and FIG. 3 is a similar diagram showing a conventional transformer. In the figure, (2) is an iron core leg, (3) is a winding, (2) is a wire, and (5) is air as a cooling medium. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Patent Attorney Masuo Odai Figure 1 2: Iron core leg 4: &! Material 3: Winding 5: Air (A> Figure 2 (B) Figure 3

Claims (3)

[Claims] (1) In a core leg and a winding made by winding a wire a predetermined number of times around the outer periphery of the core leg, the cross-sectional area of the wire is equal to the cooling An electromagnetic induction device characterized in that the temperature is changed in the length direction of the medium according to the local temperature distribution of the medium. (2) The electromagnetic induction device according to claim 1, characterized in that the cross-sectional area of the wire increases as it goes upward in the vertical direction of the winding. (3) The electromagnetic induction device according to claim 1, wherein the cross-sectional area of the wire increases as it goes inward in the radial direction of the winding.