JPS5854491B2 - Oil-filled electrical equipment tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to oil-filled electrical equipment such as transformers and accelerators, and more particularly to improvements in tanks.

Generally, in oil-filled electrical equipment, such as transformers, in order to ensure insulation performance, vapor phase drying is performed in advance to remove moisture, and then oil is vacuum-filled to ensure that the oil completely impregnates the insulation. ing.

If the capacity of the transformer mentioned above is large, a large bushing or radiator will be attached to the tank, resulting in a large external dimension as a whole.In such cases, only the contents of the transformer should be dried beforehand. However, a method is adopted in which this is stored inside a tank, and then the inside of the tank is evacuated and lubricated.

Therefore, in this type of tank structure, reinforcing beams are attached to the side plates by welding so that the tank can withstand vacuum strength.

On the other hand, vibration acceleration is applied to the transformer from the transformer mounting base during transportation or during an earthquake, and the vibration acceleration having a vibration frequency band close to the natural frequency of the system including the transformer mounting part is applied to the transformer. When the vibration is transmitted to the ground, a resonance phenomenon occurs, and the acceleration response magnification of the upper part of the transformer is several times to more than ten times the input acceleration of the lower part, and stress proportional to the magnitude of the excitation moment due to this vibration is applied to the transformer base. If the vibration occurs in a large area and is repeated a large number of times, a relatively small vibration stress may lead to fatigue failure and damage to the tank.

In addition, in recent years, in order to reduce the weight of the tank and save oil inside the tank, tanks with approximately elliptical shapes have been adopted.

As shown in FIGS. 1 to 3, the oval tank has a side plate 1 having an oval cross-sectional shape, a top band 2 attached to the upper end of the side plate 1, and a top band 2 that covers the opening at the lower end of the side plate 1. It has a bottom plate 3 provided as shown in FIG. The tank is fixed by inserting a bolt (not shown) into a hole 6 drilled in the base 4.

When an excitation force is applied to the elliptical tank, the stress distribution in the vicinity of the joint with the bottom plate 3 for excitation in the X direction becomes distribution 8a shown in FIG. 4, and the stress distribution for excitation in the Y direction is as follows:
The distribution 9a shown in Fig. 5 is obtained, and the maximum stress is σB, respectively.
X, σBY.

The maximum stress mentioned above occurs in approximately inverse proportion to the width direction dimension of the base 40 and the plate thickness of the side plate 1, so even if the acceleration entering the transformer is small, its frequency and the natural frequency of the system including the transformer mounting part When resonance occurs, when the number of repetitions is large, or when the input acceleration of the transformer is large and the excitation moment is large, the side plates and bottom plates should be The thickness must be increased, which increases material costs and the weight of the tank.

In addition, the stress distribution in the A-A cross section (Fig. 2) of the above tank is as shown in Fig. 6, as shown in Fig. 6, the strength is large in the semicircular part and reinforcement can be omitted, but near the end of the horizontal reinforcement Since the cross-sectional shape of the material changes rapidly, stress concentration occurs, resulting in a very high stress σT that exceeds the yield stress of the material.

Therefore, in order to make the tank capable of withstanding vacuum strength, the thickness of the side plate 1 is increased and the section modulus is increased in accordance with the moment generated near both ends of the horizontal reinforcement. However, this results in problems such as increased material costs, increased tank weight, poor workability, and increased processing costs.

The present invention has been made in view of the above points, and it significantly reduces the maximum stress generated due to the pressure applied to the tank, as well as the stress generated at the base of the tank, and provides a lightweight and inexpensive oil with high mechanical strength. The purpose is to provide electrical equipment tanks.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 7 to 9, the same members as in FIGS. 1 to 3 are designated by the same reference numerals.

In FIG. 7, reference numeral 10 denotes a vertical reinforcing body, and the vertical reinforcing body 10 is disposed on both sides of a horizontal reinforcing body 50 provided on the long side straight portion of the tank side plate 1.

The vertical reinforcing body 10 has a substantially V-shaped cross section, and one side 11 is joined to the end face of the horizontal reinforcing body 5, and the other side 12 is connected to the circumference of the semicircular portion of the tank side plate. It is connected to the area of minimum directional moment.

The angle θ between the other side surface of the longitudinal reinforcing body 10 and the surface of the horizontal reinforcing body 100 is set such that the other side side surface is located on a tangent to the semicircular portion.

Further, the vertical reinforcing body 10 has a lower end connected to a base 4 extending in a direction perpendicular to the long side linear portion of the tank side plate, and an upper end extending close to a top band 20 provided at the upper part of the tank side plate. .

Therefore, the pressure applied to the tank side plate when the tank is directly emptied can be reduced by installing a vertical reinforcement between the semicircular part with high strength and the horizontal reinforcement provided on the long side straight part. By locating one side on the tangent to the semicircular portion and making the cross-sectional shape change gradually, the stress concentration near the end of the horizontal reinforcing body can be significantly alleviated.

That is, by locating one side end of the longitudinal reinforcement body 10 in the minimum stress value area in the stress distribution diagram 10a of the conventional embodiment shown in FIG. 6, the stress distribution diagram 10b according to the present invention is
becomes the state shown in Fig. 12, and the maximum generated stress σTl
is a value that is less than a fraction of the maximum generated stress σT in the conventional stress distribution diagram.

On the other hand, when a transformer having the tank described above is installed, a reaction force is generated in the fixing bolt part due to the excitation moment due to vibration, and this reaction force is transmitted from the base 4 to the bottom plate 3 and the vertical reinforcement 10.
In this case, the stress distribution near the joint with the bottom plate caused by the X-direction vibration is stress 8b as shown in FIG. 10, and the maximum stress is σBX'
On the other hand, the stress distribution of the side plate with respect to Y-direction vibration is stress 9b shown in FIG. 11, and the maximum stress is σBY'.

Further, by fixing the lower end of the vertical reinforcement body 10 to the base 4, the force transmission area A increases, and by connecting the vertical reinforcement body 10 to the horizontal reinforcement body 5, the area in the height direction increases and the horizontal reinforcement body 5 The burden will also be shared by the

Furthermore, by arranging the vertical reinforcement 10 on the outside of the long side portion of the tank side plate, the distance 1 between the reaction force application points increases.

Therefore, the multiplicative product value of the force transmission area A and the distance 1 between the reaction force application points for the X-direction and Y-direction excitation can be increased several times or more compared to the conventional structure, so the maximum stress σBX', σ
BY' to σBX.

This means that it can be significantly reduced to a fraction of that of σBY.

As described above, according to the present invention, when tank pressure is applied during evacuation, etc., the stress generated at the joint between the horizontal reinforcement provided on the long side straight part and the semicircular part can be reduced compared to the conventional one. Furthermore, even if vibration acceleration is applied and a large vibration moment is generated, the stress on the side plate near the joint with the tank bottom plate can be significantly reduced compared to conventional ones. It is possible to reduce the thickness of the side plates and the bottom plate, thereby achieving the effect that material costs can be significantly reduced and the weight of the tank can be reduced.

[Brief explanation of drawings]

Figure 1 is a plan view of a conventional oil-filled electrical equipment tank, Figure 2 is a front view of the same, Figure 3 is a side view of the same, Figure 4 is a right view of stress caused by vibration in the X direction on the side plate of a conventional tank, Figure 5 is a stress distribution diagram due to the same Y-direction vibration, Figure 6 is a stress distribution diagram when pressure is applied to the conventional tank, Figure 7 is a plan view of the oil-filled electrical equipment tank of the present invention, and Figure 8 is a stress distribution diagram when pressure is applied to the conventional tank. The same front view, FIG. 9 is the same side view,
Fig. 10 is a stress distribution diagram when the side plate of the tank of the present invention is excited in the X direction, Fig. 11 is a stress distribution diagram when the side plate is excited in the Y direction, and Fig. 12 is a stress distribution diagram when pressure is applied to the tank of the present invention. It is. 1...Side plate, 2...Top band, 3
...Bottom plate, 4...Base, 5...
... Horizontal reinforcement, 10... Vertical reinforcement, 11...
...one side, 12...other side.

Claims (1)

[Claims] 1. A tank body having an elliptical cross-sectional shape, a horizontal reinforcing body installed horizontally on the long side of the tank body, and a vertical reinforcing body having a substantially V-shaped cross section and connected to the horizontal reinforcing body on one side. , the other side end of the vertical reinforcement body is connected to the minimum value area of the circumferential moment of the semicircular part of the tank body, and the surface of the other side is located on the tangent to the semicircular part. An oil-filled electrical equipment tank characterized in that the lower end of the vertical reinforcing body is connected to a base provided perpendicularly to the long side portion of the tank body.