JPS6041208A - Tank for oil-immersed transformer - Google Patents

Abstract

PURPOSE:To alleviate a stress at the corners of tank when an internal pressure increases during internal flashover fault by separating the welding line of side plates which form a tank from the tank corners, attaching a reinforcing beams and welding side plates through a plate. CONSTITUTION:A cover 1 housing the transformer body and insulating oil and a tank 2 are hermetically assembled by welding by sealing the flanges 3A, 3B attached respectively to the apertures. The tank 2 is formed so that the side plate is bend at the corner and the seaming part 12 for welding of side plate is separated from the tank corners X. The reinforcing beam 5 is welded to the side plate forming the tank 2 through the attaching plate 11 at the tank corners X.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tank for oil-filled electrical appliances such as transformers and reactors.

[Technical background of the invention and its problems] When a flash fault occurs in the tank of an oil-filled electrical appliance such as a transformer or reactor, the insulating oil filled in the tank decomposes and releases a large amount of gas. occurs, and the pressure inside the tank rises rapidly.

In the case of an internal accident with small arc energy during a flashover, the increase in tank internal pressure can be alleviated by releasing oil from the pressure relief device, such as by increasing the volume due to expansion and deformation of the tank 1 wall. However, in the event of an internal flash fault in a transformer connected to a large system capacity, increasing the volume of the tank and releasing oil from the pressure relief device will not be enough to alleviate the larger and more rapid pressure rise. Otherwise, there is a risk that the mechanically weak parts of the tank will break and spew out hot oil and gas. The ejection of high-temperature oil and gas not only damages peripheral equipment, but also comes into contact with oxygen in the atmosphere and may ignite, leading to more serious secondary disasters such as fires.

The flange joints and corners of reinforcing beams fixed to the tank peripheral wall are known to have weak mechanical strength in transformer tanks. In a general transformer tank, as shown in FIG. 1, the transformer body, the cover 1 containing insulating oil therein, and the tank 2 have flanges 3A attached to their respective openings.

3B are welded together 14 times and hermetically assembled.

A reinforcing beam 4 is fixed to the cover 1, a reinforcing beam 5 is fixed to the peripheral wall of the 20 tanks, and a reinforcing beam 6 is fixed to the bottom thereof. A pocket 1 to 7 attached to the cover 1 is for attaching a line end bushing 8.

Cover 1 and tank 2 are the parts of the transformer tank constructed in this way that have weak mechanical strength against the increase in internal pressure -F.
This is the flange joint of the tank 2 and the corner of the reinforcing beam 5 horizontally arranged on the outer circumferential wall of the tank 2. As shown in FIGS. 2 and 3, the flange joint is a connecting beam 9 designed to share the load concentration at the end of the reinforcing beam 4 of the cover 1 with the reinforcing beam 5 placed in the tank 5, and a general flange. By arranging and fixing the flange reinforcing material 10 that prevents opening deformation of the joint, its strength can be greatly improved.

A reinforcing beam 5 horizontally arranged and fixed to the outer peripheral wall of the tank 2
The bending moment distribution of each part due to the tank internal pressure P will be explained using FIGS. 4 and 5.

In both figures, the inner width of the tank is W, the inner length of the tank is L, and when the bending rust resistance of the reinforcing beam 5 is equal at both short and long sides of the tank, point A at the center of the short side of the tank, If the bending moment M at each of the 8 points at the corner and point C at the center of the long side of the tank is expressed as M/P l-, it changes as shown in Figure 5 with respect to the short side of the tank and the long side ratio W/l-. . In other words, the bending stress at the 8 corners of the tank is always constant against changes in W/L.

It can be seen that compared to points A and C of the medium heat on the long side, they are equivalent to -L. Roughly, the corners of the tank are also points of change in the shape of the reinforcing beam 5, and large stress concentration occurs therein.

Therefore, even if the bending rust resistance of the reinforcing beam 5, which is horizontally arranged and fixed to the outer circumferential wall of the tank 2, is slightly increased, a large bending stress is generated at the tank corners due to the excessive pressure inside the tank, causing cracks. There is a risk that this may occur. If cracks occur in the reinforcing beams at the corners of the tank, there is a risk that the tank side plates themselves will move back and forth, causing oil to spout out.

[Object of the Invention] An object of the present invention is to provide a tank for oil-filled electrical appliances that can suppress an increase in tank weight to a minimum and increase its breaking strength against internal pressure.

[Summary of the Invention] The tank for oil-filled electrical appliances according to the present invention houses an electrical appliance main body and insulating oil, and has a reinforcing beam arranged and fixed to the outer peripheral wall of the tank. This is characterized in that the welding lines are spaced apart and the tank side plate and reinforcing beam at the corner of the tank are welded and fixed via a backing plate.

[Embodiments of the Invention] The present invention will be described below with reference to embodiments shown in FIGS. 6, 7, and 8. In Figures 6 to 8, the first
Since the same reference numerals as those in the figures to FIG. 3 indicate the same parts, the explanation thereof will be omitted.

The present invention is characterized by a tank 2 which houses a transformer body and insulating oil therein and has a reinforcing beam 5 horizontally arranged and fixed to the outer peripheral wall, details of which are shown in FIGS. 7 and 8. One of the tank short side side plates should be bent at the corner as shown, and the welded joint 12 between the side plates should be separated from the tank corner x, and the tank 2 should be bent at the tank corner. The structure is such that the side plates and the reinforcing beam 5 are connected via the backing plate 11.

In the transformer tank according to the present invention configured in this way,
The reinforcing beam 5, which is horizontally arranged and fixed to the outer circumferential wall, can locally increase rust resistance at the corners of the tank due to the effect of the backing plate 11, and can significantly reduce stress concentration. Furthermore, the welded joints 12 between the side plates that make up the tank are also spaced apart from the tank corners. There is no risk that the side plate itself that constitutes the tank will be damaged due to rising tank internal pressure.

In the embodiment, a transformer tank has been described, but the present invention can be similarly applied to an accelerator tank or the like of the same type.

[Effects of the Invention] As described above, the oil-filled electrical tank according to the present invention has the following features: 6. Either the short side plate or the long side plate is bent at the corner of the tank, and the welded joint between the side plates is welded from the corner of the tank. In addition to the separation, the reinforcing beams placed and fixed around the outer circumference of the tank are connected and fixed to the tank side plate via the backing plate at the corner of the tank, thereby reducing the stress at the tank corner when the internal pressure increases in the event of an internal flash accident. Therefore, tank destruction can be prevented, and more important secondary disasters such as pollution and fire caused by oil and gas spouts can be prevented. Furthermore, since the increase in tank weight can be kept to a minimum, there is no problem in transporting it to the installation site.

[Brief explanation of the drawing]

Figure 1 is a schematic structural diagram of a general transformer tank, Figures 2 and 3 are detailed diagrams of its main parts, Figure 4 is a stress distribution diagram at the corners of the tank, and Figure 5 is the stress An explanatory diagram showing the distribution, FIG. 6 is a schematic configuration diagram showing an embodiment of the tank for oil-filled electrical appliances according to the present invention, and FIGS. 7 and 8 are plan views showing the corners of the transformer tank according to the present invention. and a side view. 1...Cover 2...Tank 3A, 3B...Flange 4. 5. 6... Reinforcement beam 7... Pocket 8... Bushing 9... Connection beam 1o... Flange reinforcement month 11... Back plate 1
2...Welded joint x...tank corner agent 1r Rido Kairi Ken Chika 1. + is 1 person) No. 1
Figure 2 Figure 4 Figure 5 Figure 6 Figure □ (4 ■ Eyo

Claims (1)

[Claims] In a tank for oil-filled electrical appliances, which houses the electrical appliance body and insulating oil inside, and has a reinforcing beam fixed to the outer peripheral wall,
By bending the side plates that make up the tank corners that are perpendicular to the axis of the reinforcing beam, the welded joints between the side plates are placed at a distance from the tank corners, and the reinforcing beams and side plates are roughly placed at the tank corners. A tank for oil-filled electrical equipment characterized by being fixed by welding through a plate.