JPH0378769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to electrical equipment such as transformers, and particularly to the structure of bushings thereof.

[Background of the invention]

FIG. 1 shows the conventional structure of a power plant transformer in which bushings are connected to cables. In the figure, a winding 2 is wound around an iron core 1 and housed in a tank 3, and the upper part of the tank 3 is sealed with a cover 4. The bushing 5 is connected to the winding 2 via a lead wire 6, and the bushing 5 is attached to a pocket 7 attached to the side surface of the tank 3 at an angle of θ with respect to the center line of the iron core 1. It is established in One end of a lead wire 8 is fixed to the upper end of the bushing 5, and the other end of the lead wire 8 is connected to a cable 10 via a cable head 9. The bushing 5
Shields 5a are provided at the upper and lower ends of the lead wire 6, respectively, and the shields 5a are at the same potential as the lead wire 6 and are connected to the pocket 7 on the ground side.
It relaxes the electric field between the That is, the shield 5a and the pocket 7 are configured to maintain a constant insulation distance d.

FIG. 2 shows the positional relationship between the shield 5a and the pocket 7 in a view taken along the line A-A in FIG. It forms a semicircle with radius R concentrically with the center of.

For electrical equipment such as transformers, it is desirable to transport accessories such as bushings to the site as assembled at the factory as much as possible, in order to ensure electrical reliability and to facilitate on-site assembly. However, there are restrictions on dimensions such as height and width in packaging during transportation, and the product must be packed so that the packaging dimensions fall within these limits. Since the upper part B of the pocket 7, which is the widest in FIG. 1, exceeds the limit dimension, there is a drawback that the pocket 7 may have to be separated and changed to a structure that can be transported separately.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and its purpose is to reduce the packaging dimensions so that electrical equipment such as transformers can be transported assembled at the factory without changing the mounting angle of the bushings. Our goal is to provide electrical equipment such as transformers that can be made smaller.

[Summary of the invention]

The present invention is to make the center line of a bushing installed obliquely on the tank wall of an electrical device such as a transformer and the center line of the pocket that establishes the bushing eccentric, that is, to make the center line of the bushing eccentric to the center line of the iron core. The desired purpose is achieved by making the angle of the pocket centerline smaller than the angle of the bushing centerline with respect to the iron core centerline.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electrical device according to the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention. In this figure, parts that are the same as those shown in FIG. 1 are designated by the same numbers. The only difference from the conventional example shown in FIG. 1 is the position of the center line of the pocket 7 that establishes the bushing 5, and the other parts are exactly the same as in FIG. Angle θ of the center line of the bushing 5 with respect to the center line of the iron core 1
On the other hand, there is a pocket 7 for storing the bushing 5.
The angle θ' of the center line of the iron core 1 with respect to the center line of the iron core 1 is becoming smaller.

According to this embodiment configured in this manner, the sleeve 5b constituting the bushing 5 has the same ground potential as the pocket 7, so that the portion of the pocket 7 near the sleeve 5b is electrically connected to the bushing 5. There is no need to ensure an insulating distance.
That is, the pocket 7 does not necessarily have to be concentric with the bushing 5 to ensure a radius R. However, the intersection C between the center line of the bushing 5 and the center line of the pocket 7 is located at a position that ensures the insulation distance d between the lower shield 5a of the bushing 5 and the pocket 7.

As described above, according to this embodiment, part B can be moved closer to the center of the transformer, and the equipment can be accommodated within the transport limit dimensions, so that the pocket 7 can be transported without being separated. Furthermore, since the internal volume of the transformer can be reduced, the amount of insulating oil sealed in the transformer can also be reduced. In this case, the inclination angle θ' of the pocket 7 may be made as small as possible as long as the sleeve 5b does not come into contact with the pocket 7.

In this embodiment, a pocket having a semicircular cross section has been described, but the same effect can be obtained with a pocket having a box-shaped cross section.

〔Effect of the invention〕

As described above, according to the present invention, the mounting angle of the pocket that establishes the bushing for electrical equipment such as a transformer is reduced, so the equipment can be transported with the pocket assembled, which not only improves the reliability of the equipment. The effect is significant, as it has become possible to reduce the amount of insulating oil and reduce on-site assembly costs.

[Brief explanation of drawings]

Figure 1 is a side sectional view showing the structure of a conventional transformer.
FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is a side sectional view showing one embodiment of the transformer according to the present invention. 1... Iron core, 2... Winding wire, 3... Tank, 5...
...Butting, 5a...Shield, 5b...Sleeve, 6, 8...Lead wire, 7...Pocket, 1
0...Cable.

Claims (1)

[Claims] 1. A tank for storing an iron core around which a winding is wound, and a pocket formed in the tank so as to protrude outward from the tank. The pocket is formed in the tank such that the angle of the pocket centerline with respect to the centerline of the iron core is smaller than the angle of the centerline of the bushing with respect to the centerline of the iron core. Electrical equipment characterized by: