JPS6135684B2 - - Google Patents

Description

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

Generally, oil-filled electrical equipment, such as transformers, is subjected to vapor phase drying in advance to ensure insulation performance. After moisture is removed, oil is applied under vacuum to ensure that the insulation is completely impregnated with oil.

When the capacity of the above transformer is large, large bushings and radiators are attached to the tank, which increases the external dimensions. The method used is to house the oil inside the tank, then evacuate the inside of the tank and lubricate it. Therefore, in the tank structure, reinforcing beams are attached to the side plates by welding means so that the tank can withstand vacuum strength.

On the other hand, in order to prevent the deterioration of the oil stored in the tank, there is also a known method of filling the tank with nitrogen gas. In order to keep the pressure rise within the tank below a certain level, a gas chamber is provided in a part of the tank and nitrogen gas is filled in the gas chamber. .

The above gas chamber is usually installed under the cover, but in order to lower the height of the transformer, the volume of the gas chamber under the cover is reduced, and a gas chamber is also installed on the side of the tank to serve as reinforcement. That's what I do. Furthermore, in recent years, from the standpoint of resource conservation, tanks with approximately oval shapes have been adopted in order to conserve oil within the tank and reduce the weight of the tank.

As shown in FIGS. 1 and 2, the oval tank has a side plate having an oval cross-sectional shape, and a top band 2 attached to the upper end of the side plate 1.
It has a bottom plate 3 provided to cover the lower end opening of the side plate 2, and a base 4 fixed to the lower surface of the bottom plate, and a gas chamber 5 is provided on the outer surface of the long side portion 1a of the side plate 1.
A box-shaped reinforcing body 6 is attached which defines a . The box-shaped reinforcing body is composed of a rectangular frame 7 and a plate 8 attached to the frame, and reinforcing rods 9 are laterally installed at intervals on the inner surface of the plate 8.

In the tank having the above structure, when the inside of the tank is evacuated, the pressure state of each part of the tank is as shown in FIGS. The same pressure is applied to both, and the pressure is balanced. On the other hand, at the connection between the long side portion 1a of the tank side plate 1 and the semicircular portion, that is, near the side wall attachment position of the gas chamber, the cross-sectional shape to which pressure is applied changes rapidly, and as shown in FIG. Stress concentration occurs and a very high stress σx is generated which exceeds the yield stress of the material.

Therefore, in a tank with the above structure, in order to withstand vacuum strength, the thickness of the side plate is increased according to the moment generated near the gas chamber connection part, and the section modulus is increased to reduce the maximum stress generated on the side plate. It is necessary to keep the stress below the allowable stress, but this has disadvantages such as increased material costs, increased tank weight, and poor manufacturing methods, resulting in increased processing costs.

The present invention has been made in view of the above points, and
The purpose of the present invention is to provide oil-filled electrical equipment that can significantly reduce the maximum stress generated in a tank due to the pressure applied to the tank, reduce the thickness of the tank, reduce the weight of the tank, and improve workability.

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

In FIGS. 6 to 8, the same members as in FIGS. 1 to 3 are designated by the same reference numerals.

In FIG. 6, reference numeral 10 indicates a reinforcing plate, and the reinforcing plate 10 is provided at each of the four corners of the box-shaped reinforcing body 6.

The reinforcing plate 10 is a rectangular plate, and has one end connected to a corner of the box-shaped reinforcing body 6, and the other end connected to a connecting part 11 between the long side portion 1a and the semicircular portion 1b of the side plate 1. connected. The inclination angle θ of the reinforcing plate 10 is determined such that the reinforcing plate 10 is located on a tangent to the semicircular portion 1b of the connecting portion 11.

That is, the joining position of the reinforcing body 10 on the tank side is located in the area of the minimum circumferential moment of the semicircular portion 1b of the side plate.

When the tank is evacuated, the pressure applied to the side plate of the tank is as shown in FIG. It joins the sides, balances, and is in a state where no pressure is applied. In addition, since the reinforcing plate connected to the box-shaped reinforcement is located on the tangent line of the semicircular part, the cross-sectional shape changes relatively gradually, reducing stress concentration near the connection of the box-shaped reinforcement to the tank side plate. can be significantly alleviated.

That is, in the stress distribution of the tank, as shown in FIG. 10, the maximum stress σx' of the present invention is reduced to a fraction of the maximum stress σx of the conventional stress distribution (dotted line).

As described above, according to the present invention, when pressure is applied to the tank such as during evacuation, the stress generated at the connection between the reinforcing body that also serves as a gas chamber provided on the side plate of the tank and the semicircular part of the tank can be reduced compared to the conventional one. It can be made significantly lower than a structural tank, and therefore, the thickness of the tank side plate can be made thinner to reduce the weight of the tank, and material costs and processing costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a conventional tank, Fig. 2 is a front view of the same, Figs. 3 and 4 are diagrams showing the pressure state of the conventional tank, Fig. 5 is a stress distribution diagram of the same, and Fig. 6 is a diagram of the same. A plan view of the tank of the present invention, FIG. 7 is a front view thereof, FIG. 8 is a sectional view taken along line - in FIG. 7, FIG. 9 is a pressure state diagram of a cross section taken along line - in FIG. 1
Figure 0 is a stress distribution diagram. DESCRIPTION OF SYMBOLS 1... Side plate, 1a... Long side part, 1b... Semicircular part, 10... Reinforcement plate, 11... Connection part, θ...
...angle of inclination.

Claims (1)

[Claims] 1. In an oil-filled electrical equipment tank having a tank body having an elliptical cross-sectional shape and a box-shaped reinforcing body fixed to the outer surface of the long side portion of the side plate of the tank body to define a gas chamber, the above-mentioned box-shaped reinforcement Connecting reinforcement plates are provided at the corners of the body, one end of which is connected to the box-shaped reinforcement body, and the other end is connected to the minimum area of the circumferential moment of the semicircular part of the side plate of the tank body, and further connection reinforcement is provided. An oil-filled electrical device characterized in that the surface of the plate is located on a tangent to the semicircular portion.