JP7824907B2 - Oil-filled pole-mounted transformer - Google Patents

Description

The present invention relates to an oil-immersed pole-mounted transformer with a built-in arrester.

Distribution transformers, such as pole-mounted transformers that change the voltage and supply electricity through distribution lines, are primarily composed of a transformer body with an iron core and windings wound around the iron core, and an outer box that houses the transformer body.

Some distribution transformers have an arrester (surge protector) inside the transformer as a lightning protection measure, and for such transformers, the arrester must be installed in the oil or gas space above the inside of the tank transformer.

The structure is such that the arrester mounting bracket with the arrester attached is attached to the internal mounting bracket that attaches the transformer internals (iron core, primary coil, secondary coil, upper and lower fastening brackets) to the tank.

For example, Patent Document 1 discloses an invention for a gas-insulated transformer in which an inert gas with higher dielectric strength than air is sealed as an insulator, and a gapless arrester connected to the line end of the transformer coil is built into the sealed gas.

Specifically, the internal mounting bracket (the U-shaped cross-section bracket in the figure, located between the iron core 6 and the tap changer 7) is attached to the short side of the top fastening bracket inside the transformer, and the arrester mounting bracket is attached to the internal mounting bracket, thereby enabling the arrester to be built into the tank.

Patent document 2 discloses an invention for a transformer in which a common mounting bracket bent into an L shape is attached to a terminal block above the transformer windings inside a tank filled with insulating oil, SF6 gas, or other insulators, and three-phase lightning arresters connected to high-voltage leads led from the overhead line through a switch are fixed to the common mounting bracket.

Japanese Unexamined Patent Publication No. 61-190910 Japanese Patent Application Publication No. 1-222417

The gas-insulated pole transformer in Patent Document 1 has arrester mounting brackets attached to the inner mounting brackets on the short sides, which improves workability, but manufacturing costs increase if the insulation method is changed to oil insulation.

The arrester in Patent Document 1 is attached above the mounting position of the fixing bolts used to secure the contents of the internal mounting bracket of the gas-insulated pole-mounted transformer to the tank.

In gas-insulated pole transformers, an inert gas is sealed inside the tank as an insulator, so the arrester can be installed anywhere inside the tank and be covered with inert gas. However, because the arrester in an oil-filled transformer is placed in oil, a certain amount of oil is required to reach a certain depth below the oil surface. If the arrester mounting bracket is installed so that it extends upward from the inner mounting bracket, the arrester position will be higher, and the amount of insulating oil required will increase.

As such, applying the gas-insulated pole transformer invention of Patent Document 1 to an oil-filled transformer using insulating oil poses the problem of high manufacturing costs.

The object of the present invention is to provide an oil-immersed pole-mounted transformer with a built-in arrester that can reduce manufacturing costs.

The above objectives are achieved by an oil-filled pole-mounted transformer that includes a transformer interior having an iron core and a winding wound around the iron core, and a container that houses the transformer interior, and is equipped with a top fastening bracket attached above the transformer interior and an interior suspender that connects an interior fixing seat attached to the inner wall of the container, and is equipped with an arrester mounting structure on the interior suspender above the transformer interior, and the arrester mounting structure is located between the mounting portion of the interior suspender with the interior mounting seat and the mounting portion of the interior suspender with the top fastening bracket.

The present invention makes it possible to provide an oil-immersed pole-mounted transformer that can reduce manufacturing costs.

1 is a schematic diagram of a transformer to which the present invention is applied; 1 is a schematic plan view of the inside of a transformer to which the present invention is applied; 1 is a schematic diagram of the front of the upper part of the inside of a transformer to which the present invention is applied. FIG. 1 is a schematic plan view of a transformer to which the present invention is applied, in which a spacer is added to the upper portion of the interior thereof. FIG. 1 is a schematic front view of a transformer to which the present invention is applied, with a spacer added to the upper portion of the interior thereof. 1A and 1B are three-view diagrams of an upper fastening fitting to which the present invention is directed. 1 is a three-view diagram of an internal hanging fitting to which the present invention is directed.

Embodiments of the present invention will be described below with reference to the drawings. Note that in each drawing used to explain the embodiments, identical components will be given the same names and symbols wherever possible, and repeated explanations will be omitted.

A schematic diagram of a transformer to which the present invention pertains is shown in Figure 1. As shown in Figure 1, the transformer to which the present invention pertains has a container consisting of a tank 11 and a cover 10, and the container houses a transformer internals 12 consisting of an iron core 13 and windings wound around the iron core 13.

It is desirable that the container be sealed. Furthermore, when the tank 11 and cover 10 are integrated, they may be collectively referred to as the outer box. The transformer in the following examples will be described as an oil-filled transformer, which contains insulating oil, a liquid used for insulating and cooling the transformer body, inside the outer box.

Figure 1 is a schematic diagram of a transformer to which the present invention is directed. The transformer interior 12, which includes an iron core sandwiched between an upper fastener 14 and a lower fastener 15 and a winding wound around the iron core, is contained in a tank 11.

The top fastening bracket 14 is fixed to the inner suspending bracket 16 with bracket fixing bolts and nuts 24. The inner suspending bracket 16 has a U-shaped structure consisting of a horizontal long side and vertical short sides at both ends bent in the opposite direction to the transformer inner suspending bracket 12.

An insulator base 28 is installed near the center of the long side, and an arrester 17 is fixed with bolts toward the insulator base 28 on the short side closer to the transformer interior 12, and a bracket fixing bolt 25 is located above the arrester to fix the interior suspending bracket 16 to the tank 11.

In this embodiment, an example is described in which the tank is fixed to the tank 11 with bolts, but bolts are not necessarily required. A contents fixing seat for hanging the contents hanging bracket 16 may also be provided on a receiver protruding from the tank 11.

The arrester 17 must be covered with insulating oil for insulation, and in this example, it is sufficient for the insulating oil to be filled up to the dashed line indicated by 30.

Figure 2a is a schematic plan view of the upper part of the transformer interior to which the present invention is applied. An interior sling 16 is attached to the top fastening 14, and an insulator base 28 is installed in the center of the interior sling 16. Arrester 17 is fixed horizontally to both the left and right ends of the interior sling 16, and is installed so that the tip of the insulator base 28 and the arrester 17 are at a predetermined distance.

This example describes a method of fixing the bolts protruding from the arrester 17 with nuts, but the installation method depends on the specifications of the arrester 17, so the internal suspension fittings must have an arrester installation structure that meets the installation specifications of the arrester 17.

Figure 2b is a schematic diagram of the front view of the upper part of the transformer interior that is the subject of this invention. The arrester 17 is fixed to the vertically bent ends of the interior hanging bracket 16, near the transformer interior 12, with bracket fixing bolts 25 installed at the top. Since the arrester 17 must be covered with insulating oil, installing it as close to the transformer interior 12 as possible can reduce the amount of insulating oil required.

Figure 4 is a three-view diagram of the upper fastening fixture that is the subject of this invention. It has an insulator base fixing hole 29, a fixing band hole 18, and an inner hanging fixture fixing hole 21.

Figure 5 is a three-view diagram of the internal suspension bracket that is the subject of this invention. The insulator base fixing holes 29 and internal suspension bracket fixing holes 21 are provided on the long sides, while the arrester mounting holes 22 and internal fixing holes 23 are provided on the short sides.

Example 2 will be explained using Figures 3a and 3b. Figure 3a is a schematic plan view of the transformer to which the present invention applies, with a spacer 27 added to the upper part of the interior. The difference from Figure 2a is that a spacer 27 has been added to the attachment point of the arrester 17 to the short side of the top fastening bracket 14. The arrester 17 must be installed at a specified distance from the insulator base 28.

In large-capacity transformers, the diameter of the tank 11 also increases, so it is necessary to insert a spacer 27 to adjust the distance between the arrester 17 and the insulator base 28 to an appropriate distance. For this reason, a spacer 27 is placed between the arrester 17 and the internal hanging bracket to adjust the distance between the arrester 17 and the insulator base 28. A washer, nut, etc. may also be used as the spacer 27.

Furthermore, since the insulator base 28 may not be installed exactly in the center of the tank, it is desirable to be able to adjust the distance between the arrester 17 and the insulator base for each arrester mounting section.

Figure 3b is a schematic front view of the transformer interior, which is the subject of the present invention, with a spacer 27 added to the top. Even with the spacer 27 added, the arrester 17 can be installed at a lower position than the metal fitting fixing bolts 25 used to secure the transformer interior 12 inside the tank 11, thereby reducing the amount of insulating oil required.

10 Cover, 11 Tank, 12 Transformer Internal, 13 Core, 14 Top Fastening Bracket, 15 Bottom Fastening Bracket, 16 Internal Lifting Bracket, 17 Arrester, 18 Fixing Band Hole, 19 Internal Fixing Base, 21 Internal Lifting Bracket Fixing Hole, 22 Arrester Mounting Hole, 23 Internal Fixing Hole, 24 Bracket Fixing Bolt/Nut, 25 Bracket Fixing Bolt, 26 Tap Change Base, 27 Spacer, 28 Insulator Base, 29 Insulator Base Fixing Hole, 30 Insulating Oil

Claims (5)

An oil-filled transformer having a transformer body having an iron core and a winding wound around the iron core, and a container for accommodating the transformer body,
The transformer includes an upper fastening metal fitting attached to the top of the transformer contents, and a contents hanging metal fitting provided on the inner wall of the container for connecting the contents fixing seat,
The inner suspension bracket at the upper part of the transformer is provided with an arrester mounting structure,
The arrester mounting structure is an oil-filled pole-mounted transformer that is arranged between the mounting portion of the internal suspension bracket with the internal mounting seat and the mounting portion of the internal suspension bracket with the upper fastening bracket mounting portion. In claim 1,
The arrester mounting structure of the oil-immersed pole-mounted transformer is an arrester fixing hole located below the mounting portion of the internal hanging bracket and the internal mounting seat extending upward. In claim 2,
An oil-immersed pole-mounted transformer in which an arrester is attached horizontally in the arrester fixing hole. In claim 3,
An oil-immersed pole-mounted transformer in which an arrester is attached to the arrester mounting structure via a spacer so that the arrester mounting position can be adjusted. In claim 4,
The contents hanging fittings have attachment portions for attachment seats on both ends,
The arrester mounting structure is provided between the mounting portion and the upper fastening fitting,
An oil-immersed pole-mounted transformer in which a fixed distance is maintained between the insulator base and the arrester mounted on the arrester mounting structure.