JPS61228605A - Oil-filled induction electric apparatus - Google Patents

Abstract

PURPOSE:To prevent the thermal destruction of a bushing by interrupting the flow of a high temperature insulation oil spouted from a winding by providing a barrier made of an insulating material at the lower part of the bushing of an oil-filled induction electric apparatus. CONSTITUTION:A pipe 6 from the top of a tank 1 is connected to the side of the bottom of the tank 1 with a pipe 3b through a cooler 4 and an oil pump 5. A barrier 8 made of an insulating material is attached to cover the top of a transformer 2 from the upper surface inside the tank 1 and to separate the lower parts of bushings 2a, 2b and the upper part of the transformer 2. Lead wires 7a, 7b are provided to penetrate the holes made in the barrier 8. In this construction, an insulating oil 1c heated by the transformer 2 is interrupted by the barrier 8 and directly flows in the pipe 6 at the top of the cooler 4 without flowing to the lower parts of the bushings 2a, 2b. Accordingly, even if the highest temperature of the transformer rises, the lower parts of the bushings 2a, 2b are not overheated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an oil-filled induction electric appliance, and particularly relates to an improvement in which the oil temperature at the lower part of the bushing is lower than the maximum oil temperature of the induction electric appliance body.

[Technical background of the invention and its problems]

In response to the remarkable growth in demand for electricity in recent years, the capacity of power transmission lines has been increased, and in response, the capacity of oil-filled induction electrical equipment such as transformers and accelerators has also increased. However, in our country, there are strict transportation restrictions such as railway transportation, and there is a strong desire for a technology for downsizing oil-filled induction devices that will not exceed the transportation restrictions even if the capacity is increased.

In order to meet these demands, we used insulating materials such as amine-added paper and film insulating paper, which can withstand higher temperatures than general insulating paper, for the insulating materials of induction electric appliances, increasing the current density of the nine windings and increasing the cross-sectional area of the windings. Research is being conducted to increase the capacity of induction appliances by increasing the total current without changing it.

However, with such means, it is not possible to raise the temperature of the entire induction electric appliance very much, and therefore the current density of the winding cannot be increased, and it is not possible to reduce the size of the induction electric appliance.

The above points will be explained in more detail. FIG. 3 shows the structure of a general conventional oil-immersed induction electric appliance 1, such as an oil-immersed transformer. That is, the transformer body 2 with the windings wound around the iron core is stored inside the tank 1, and bushings 2a and 2b are attached to the pushing pockets 1a and 1b provided in the tank 1, respectively, and the windings of the transformer body 2 and each connected, tank 1
An insulating oil IC is sealed inside. In addition, a cooler 4 and an oil feed pump 5 are connected between the bushing pocket IJI and the vicinity of the bottom of the tank 1 through pipes 3a and 3b, and the insulating oil 1c inside the tank 1 is cooled and circulated from the bushing pocket 1a to the bottom of the tank 1. configured to do so.

FIG. 4 shows the temperature distribution during operation of such a conventional oil-immersed transformer. In other words, if the vertical axis represents the vertical position within the winding, and the horizontal axis represents the temperature rise relative to the ambient temperature, then
Straight line AB shows the temperature distribution of the insulating oil and increases linearly along the one-turn resistance height.

The straight line CD indicates the temperature distribution of the winding, and increases linearly along the height of one winding in parallel with the oil temperature. Furthermore, point B indicates the highest point temperature of the winding.9. Generally, υ is also higher than the average temperature point at the top of the winding. Therefore, if the temperature rise value at point H is θH8, it is expressed as θH3”θOM+g+radius (1). Here, 00M is the average oil temperature rise 1g is the difference between the average oil temperature rise and the winding average temperature rise. Gyyy.

is the difference between the winding highest point temperature and the winding average temperature.

According to JRC-204 (1978), the value of 6 m is 10°C in the case of forced oil circulation.

On the other hand, g is g ” Ks (LLL)'...(
2). Here, is the proportionality constant and LLL is the load loss.

n is a constant and is generally referred to as KO, 8-1, 0.

Also, if the maximum temperature rise is 00, 00 is θo −=
Kg (Lsx, + LLL)”...(
3). Here, is a constant determined by the winding.

LNL is no-load loss, LLL is load loss, and 1m is a constant representing the dependence of loss on temperature rise, which is generally referred to as KO38.

It is now assumed that by using a highly heat-resistant insulating material, the maximum temperature of the coil winding can be made higher than before. Furthermore, if the cross-sectional area of the conductor is reduced and the current density is increased in order to downsize the transformer, the resistance of the first winding increases, so that the load loss LLL increases. Therefore, according to equation (2), as g increases, eHs also increases, but there is no abnormality in the folded windings, which are made of highly heat-resistant materials. However, at the same time, according to equation (3), the maximum oil temperature rise is θo4^. This means that the oil temperature under the bushings 2a, 2b of the transformer is higher than before.

That is, the ambient temperature of the bushings 2a and 2b will become high, and in order to prevent the bushings from thermal damage,
It becomes necessary to reduce the temperature rise by replacing the bushing with one with a higher rating, or to reduce the maximum temperature rise by increasing the number of external coolers 4. This had the problem of making the transformer as a whole large and expensive.

[Purpose of the invention]

The present invention has been made in consideration of the above points.

The purpose of this is to increase the current density of the first winding so that even if the maximum oil temperature rises, the oil temperature at the bottom of the bushing does not rise, and the bushing is changed to a larger capacity one. 9. It is necessary to increase the capacity of the cooler. The purpose of the present invention is to provide an oil-filled induction electric appliance that is small, lightweight, and inexpensive.

[Summary of the invention]

According to the present invention, this object is achieved.

A barrier made of an insulating material is provided at the bottom of the bushing of the oil-filled conductor to prevent the high temperature insulating oil that blows up from the first winding from flowing in, thereby preventing heat damage to the bushing and making it compact, lightweight, and inexpensive. It is characterized by

[Embodiments of the invention]

An embodiment of the oil-filled induction electric appliance of the present invention will be described below with reference to FIG. The same parts as in FIG. 3 are given the same reference numerals.

Oil-immersed induction electric appliances such as transformers and accelerators, such as oil-immersed transformers, are shown in Figure 1.

A transformer body 2 including an iron core and a winding wound around the iron core is housed inside the tank 1, and bushings 2a are placed in bushing pockets la and lb provided in the tank 1, respectively.
. The cooler 4 is connected to the bottom side of the tank 1 via a pipe 6 from the top of the tank 1, via an oil feed pump 5, and via a pipe 3b. Then, a barrier 8 made of an insulating member is attached so as to cover the upper part of the transformer body 2 from the upper surface inside the tank 1 and partition the lower part of the bushings 2a e 2 b from the upper part of the transformer body 2.

Note that the lead wires 7m and 7b are provided so as to pass through holes made in the barrier 8.

With this configuration, the insulating oil 1c heated in the transformer body 2 is blocked by the barrier 8 and does not flow to the lower parts of the bushings 2a, 2b, but directly to the upper part of the cooler 4. Flows into pipe 6. Therefore, even if the maximum oil temperature of the transformer increases, the bushings 2a, 2
The lower part of b is not overheated. Therefore, even if the transformer main body 2 is made smaller by increasing the winding current density, the bushings 2a and 2b will not be damaged by heat.

Next, another embodiment of the present invention will be described with reference to FIG.

The same parts as in FIG. 1 are given the same reference numerals.

The bushing pocket 1a is connected to the bottom side of the tank 1 via a pipe 6, a cooler 4 and an oil pump 5, and then a pipe 3b to the bottom side of the tank 1, and a bushing pocket 1a is connected to a pipe 3b via a pipe 9, and then the bushing Pocket) lb is connected to piping 3b by piping 10. Other configurations are similar to the embodiments of the present invention.

By configuring it like this, the pushing hole)
Piping to la and lb9. Insulating oil 1 cooled by IOK
By flowing the oil, the oil temperature at the bottom of the bushings 2a and 2b can be further lowered than in the embodiment of the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, a barrier made of an insulating material that partially partitions the transformer main body and the lower part of the bushing is provided in the upper part of the tank, and is connected to the cooler via piping from the upper part of the tank. By doing so, it is possible to increase the current density in the first winding, downsize the transformer body, and provide a compact, lightweight, and inexpensive thin transformer.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the oil-filled induction electric appliance of the present invention. FIG. 2 is a sectional view of another embodiment of the invention. Figure 3 is a cross-sectional view of a conventional oil-filled induction electric appliance. FIG. 4 is a general temperature distribution diagram of FIG. 1...Tank, LA, LB...Bushing pocket. 1c...Insulating oil, 2...Transformer body. 2a, 2b...Bushing, 3b...Piping. 4...Cooler, 5...Oil pump. 6.9.10 ... Piping, 7m, 7b-Lead wire. 8...Bariya.

Claims (2)

[Claims] (1) A main body of an induction electric device including an iron core and a winding wound around the iron core is stored in a tank, insulating oil is sealed in the tank, and at least a part of the insulating member of the main body of the induction electric device is In an oil-filled induction electric appliance that uses a highly heat-resistant insulating material, a bushing is provided at the top of the tank, and a cooler is provided outside the tank, the bushing is placed at the bottom of the bushing so that the oil flowing inside the tank does not flow into the bottom of the bushing. An oil-filled induction electric appliance characterized in that a barrier made of an insulating material is provided at the top. (2) A pipe is provided between a lower part of the tank, a lower part of an external cooler, and a lower part of the bushing, and insulating oil is forced to flow from the lower part of the cooler to the lower part of the bushing. The oil-filled induction electric appliance described.