JPS6135683B2 - - 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, in order to ensure insulation performance in oil-filled electrical equipment, such as transformers, it is necessary to perform vapor phase drying in advance to remove moisture and then apply oil under vacuum to completely impregnate the insulator with oil. ing.

However, when the capacity of the transformer is large, large bushings and radiators are attached to the tank, which increases the external dimensions, so only the contents of the transformer are dried in advance and stored inside the tank. After that, I evacuate the tank and lubricate it. Therefore, in the tank structure, reinforcing beams are attached to the side plates by welding, so that the tank can withstand vacuum strength.

On the other hand, in order to prevent the oil stored in the tank from deteriorating, there is a known technical means of filling the tank with nitrogen gas. A gas chamber is formed in a part of the tank in order to control the pressure rise within the tank to below a certain value.

The gas chamber mentioned above is generally installed under the cover, but for reasons such as lowering the height of the transformer, the volume of the gas chamber under the cover is reduced, and a gas chamber is also provided on the side of the tank to serve as reinforcement. Furthermore, in order to reduce the weight of the tank and save oil inside the tank, a tank with a substantially oval shape is adopted.

As shown in FIGS. 1 and 2, the oval tank includes a side plate 1 formed in an oval shape, a top band 2 attached to the upper end of the side plate 1, and a bottom plate 3 provided at the lower end opening of the side plate 2. and a base 4 fixed to the bottom plate 3, and a box-shaped reinforcing body 6 defining a gas chamber 5 is attached to the outer surface of the long side portion 1a of the side plate 1. The box-shaped reinforcement body 6 is
A rectangular frame 7 and a plate 8 attached to the frame 7
The reinforcing plates 9, 9 are installed horizontally on the plate body 8.

In a tank with the above structure, the pressure state that occurs when the inside of the tank is evacuated is shown in Figures 3 and 4.
As shown in the figure, the same pressure is applied to both sides of the long side 1a of the tank side plate 1, that is, the inside of the tank and the gas chamber side, and the pressure is balanced, but the long side of the tank side plate 1 At the connection between the portion 1a and the semicircular portion, that is, near the side wall of the gas chamber, the cross-sectional shape to which pressure is applied changes rapidly, and as shown in Figure 5, stress concentration occurs and the yield stress of the material is exceeded. A very high stress σx occurs.

Therefore, in a tank with the above structure, in order to withstand vacuum strength, the thickness of the side plate 1 is increased in accordance with the moment generated near the gas chamber connection part, and the section modulus is increased to reduce the maximum stress generated in the side plate. It is necessary to keep the stress below the allowable stress, but this has disadvantages such as increased material cost and tank weight.

The present invention has been made in view of the above points, and
The purpose of the present invention is to provide an oil-filled electrical equipment tank that can significantly reduce the maximum stress generated in the tank due to the pressure applied to the tank, reduce material costs by reducing the thickness of the plate, and further reduce the weight of the tank. shall be.

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 denotes a reinforcing member, and the reinforcing member 10 is constructed by bending a narrow plate into a V-shape at the center in the width direction. The length of the reinforcement member 10 preferably corresponds to the height of the tank side plate 1, and the length of the reinforcement member 10 preferably corresponds to the height of the tank side plate 1.
A recess 12 is formed on one side of 0. The width of the recess 12 corresponds to the length of the box-shaped reinforcing body 13 in the vertical direction. The reinforcing member 10 forms both side walls 14 of the box-shaped reinforcing body 13 by fitting recesses into both side portions of the box-shaped reinforcing body 13 .

On the other hand, the side wall body 14 of the box-shaped reinforcing body 13 is inclined at an angle θ with respect to the plane of the plate body 8, and the end of the side wall body 14 is shaped so that the moment in the circumferential direction of the semicircular portion 1b of the side plate is Located in the minimum value area. The inclination angle θ of the side wall 14 is an angle at which the outer surface of the side wall is located on a tangent to the semicircular portion 1b at the welded portion.

When the tank is evacuated, the pressure applied to the tank side plate is as shown in Figure 9, and the side plate 1a on the long side of the tank is balanced, with the same pressure being applied to the inside of the tank and the gas chamber side. .

Furthermore, since the side wall 14 of the reinforcing body 13 is located on the tangent to the semicircular portion 1b of the side plate 1, the cross-sectional shape changes relatively gradually, reducing stress concentration near the connection of the gas chamber side wall to the tank side plate. can be significantly alleviated.

That is, the stress distribution of the tank is as shown in FIG. 10, and the maximum stress σx' of the present invention is reduced to a fraction of the maximum stress σ1x of the conventional stress distribution (dotted line).

Furthermore, by extending the reinforcing member 10 above and below the gas chamber, the top band 2 and the bottom plate 3
The reinforcing member shares the load acting near the fulcrum, further relieving stress concentration at the joint between the side wall and the side plate.

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 provided on the side plate of the tank that also serves as a gas chamber and the semicircular portion of the tank is reduced. Therefore, it is possible to reduce the thickness of the tank side plate to reduce material costs and reduce the weight of the tank.

[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 in a cross section taken along line - in FIG.
The figure is a stress distribution diagram. DESCRIPTION OF SYMBOLS 1... Side plate, 1a... Long side part, 1b... Semicircular part, 2... Top band, 10... Reinforcement member, 12... Recessed part, 13... Box-shaped reinforcement body, 14...
...side wall.

Claims (1)

[Claims] 1. An oil-filled electrical equipment tank that has a tank body with an elliptical cross-sectional shape and a box-shaped reinforcing body that is fixed to the outer periphery of the long side of the side plate of the tank body and defines a gas chamber. A reinforcing member is provided on one side with a recess that fits into the box-shaped reinforcing body,
The reinforcing members are fixed on both sides of the box-shaped reinforcing body so as to constitute both side walls of the box-shaped reinforcing body, and the ends of the side wall forming portions of the reinforcing members are connected to the circumference of the semicircular portion of the side plate of the tank body. An oil-filled electrical device, characterized in that it is fixedly installed in an area with a minimum directional moment, and the outer surface of the side wall is located on a tangent to the semicircular portion.