JPH06275440A - Transformer - Google Patents

Abstract

PURPOSE:To increase an insulation reliability by making a part of a gas duct where a lighting arrester is installed larger than a part where gas separation spacer is connected to. CONSTITUTION:On one end of a duct 11 which is installed at the gas side of a bushing 9, the bushing 9 is installed. Another end is connected to a lighting arrester 12. The duct gradually gets narrower after being provided with the arrester 12, forming a horn-like shape, and the other end is connected to a gas separation-type insulating spacer 20. Where the size of the duct before a part where the arrester 12 is installed is D2 and the size of the duct where the gas separation spacer 20 is connected to is D1, D2 is larger than D1. By this method, such a transformer can be obtained that the arrester can be restored easily when it has a trouble at the site and a bushing duct section has a good insulation reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer, and in particular, a large-capacity, high-voltage transformer is used to form a unit transformer by dividing a single-phase transformer into at least two parts. The present invention relates to a transformer having a duct part in which lead wires having a common electric potential are taken out and stored in a common duct, connected to an oil / gas division bushing, and a lightning arrester is connected on a gas bus side.

[0002]

2. Description of the Related Art In recent years, due to rising land prices in cities and the like, power supply sites such as power plants are often constructed at locations away from power demand sites. Therefore, recently, UHV power transmission has been studied as a power transmission from a remote distance.
In such UHV power transmission, substations are often installed in the mountains, but transformers installed in such substations are also manufactured within the strict transportation restrictions, as in the past. Due to its high voltage and large capacity, a unit transformer in which a three-phase transformer is multi-divided is being studied.

One phase of the above-mentioned transformer will be described with reference to FIG. In the figure, unit transformers 1A and 1B
Each of the tanks 2 has an iron core 3 and windings 4 housed therein. Reference numeral 5 denotes a bushing duct connected to the unit transformers 1A and 1B. Inside the duct 5, there are a high voltage lead wire 7 and a medium voltage lead wire 8 having a common electric potential with the unit transformers 1A and 1B. The high-voltage lead wire 7 and the medium-voltage lead wire 8 are housed and connected to a gas-insulated device (not shown) via a bushing 9 and a bushing 6, respectively. When transporting to the field, unit transformer 1
A, 1B, duct 5, etc. are transported separately and assembled and integrated on site.

By the way, the bushing 9 has approximately T
A gas duct 10 branched into a mold is attached, and a lightning arrester 12 is connected through the duct 10. Further, a gas insulation device (not shown) is connected to the opposite side of the branched T-shaped duct 10 via a gas duct 15, a spacer 14, and the like. The size of the gas duct 10 in the bushing 9 portion, the size of the T-shaped duct portion, and the size of the gas duct 15 are substantially the same.

[0005]

However, the transformer having the above structure has the following problems. (1) For example, when the arrester 12 fails, the insulating gas inside is recovered and the flange 16 of the T-shaped duct portion is disassembled. In that case, for example, if the gas duct 10 or the gas duct 15 to which the bushing is attached is large. As a result, the amount of gas increases, which requires a long time for gas recovery and also requires recovery. Therefore, it is necessary to make the size of the duct as small as possible.

On the other hand, when the duct is made small, the insulation strength becomes a problem. That is, SF ₆ gas used as an insulating medium causes electric field-dependent dielectric breakdown. Therefore, in the bushing 9, the gas duct 10 needs to be large because the bushing shield is attached, and even if the gas duct 10 is made small, there is a certain limit. Further, since the conductor 17 connecting the lightning arrester 12 and the bushing 9 is of T type, there is a problem that the electric field of the conductor portion becomes high when the gas duct 10 is made small. In this way, there is a contradictory relationship between the on-site recovery measures for failure and insulation reliability.

(2) As described above, the portion of the gas duct 10 on the bushing side to which the arrester is attached is formed in a substantially T shape as shown in FIG. That is, in the figure, 10 is a gas duct on the bushing side, and 13 is a gas duct for connecting a lightning arrester. Both ducts are attached by welding. In the case of such a configuration, in order to facilitate the connection between the bushing duct and the duct to which the lightning arrestor is attached, the tip portion of the duct from the lightning arrester is formed in an arc shape. At that time, if the diameter of the duct to which the bushing is attached is small, it is necessary to increase the biting into the arc shape by that amount, which makes processing difficult.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a transformer which can be easily restored even if the lightning arrester fails in the field and the insulation reliability of the bushing duct portion can be improved. It is in.

[0009]

In order to achieve the above object, the present invention divides one phase of a unit transformer into at least two tanks, and connects the lead wires of a common potential from each tank to the unit transformer. In the transformer, the transformer is arranged inside the duct attached to the container and taken out, and at least two lead wires having a common electric potential are connected to the gas duct through an oil / gas separation type bushing attached to the duct. A lightning arrester is connected at a gas duct portion connected via a bushing, and is connected to another gas duct at another portion of the gas duct via a gas division spacer, and the size of the gas duct at the portion to which the lightning arrester is attached is set to the gas division. It is characterized in that it is made larger than the size of the gas duct attached through the spacer.

[0010]

According to the transformer of the present invention, the gas duct to which the lightning arrester is attached has a bushing pocket portion larger than the gas duct of the gas insulation device up to the T-shaped duct portion, and after the T-shaped duct is branched, the duct is narrowed to reduce the gas. After installing spacers that can be divided, they are connected to gas-insulated equipment. Therefore, even if the lightning arrester fails in the field, the duct is large up to the part to which the lightning arrestor is attached, and other parts are smaller, and the gas insulation device is also separated by the spacer of the gas division, so the amount of gas recovery is small. Less is required, and the amount of time required for recovery can be improved. In addition, since the duct is large in the portion where the T-type lead is attached, the insulation reliability is also improved. Further, even in the case of manufacturing the duct, since the duct on one side is large, it is possible to reduce the number of arcuate notches, which facilitates the manufacturing.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. The same parts as those of the conventional example described above are designated by the same reference numerals, and the description thereof will be omitted. FIG. 1 is a schematic diagram of an embodiment of the present invention. In the figure, reference numeral 11 denotes a duct attached to the gas side of the bushing 9, which is substantially T-shaped. The bushing 9 is attached to one end of the duct 11 as in the conventional case, and the other end is connected to the lightning arrester 12. Then, the other end forms a blunt duct whose size is gradually reduced after the duct to which the arrester 12 is attached, and is connected to the gas division type insulating spacer 20. That is, assuming that the size of the duct before the portion where the lightning arrester 12 is attached is D2 and the size of the duct at the portion connected to the gas division spacer 20 is D1, the relationship of D2> D1 is established between D1 and D2. Is established.

Next, the operation of this embodiment will be described.
In the present embodiment, the diameter of the duct at the portion to which the lightning arrester 12 is attached is larger than the size of the duct at which the gas division type spacer 20 is attached.
The electric field is not concentrated in the T-shaped portion of the conductor 17 having the T-shaped configuration connected with the insulation reliability is improved. Further, up to the T-shaped gas duct portion of the duct to which the lightning arrester 12 is attached, the bushing pocket portion is made larger than the gas duct of the gas-insulated device, and the duct after branching the T-shaped duct is made thin.
Since the gas division spacer 20 is attached and connected to the gas insulation device, even if the lightning arrester 12 fails in the field, for example, the duct is large up to the portion to which the lightning arrester 12 is attached, and the gas insulation device is also small. Since it is divided by the gas division spacer 20, the amount of gas recovery is small, and the gas can be recovered quickly. Further, even when the duct is manufactured, since the duct is formed large, the arc-shaped cutouts of the duct on the side to which the lightning arrester is attached can be reduced, which facilitates the manufacturing.

FIG. 2 is a schematic diagram of another embodiment of the present invention. The same parts as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 2, reference numeral 21 is a shield attached to the end of the bushing 9.
The through hole 23 is provided in the through hole 23, and the lightning arrester 1 is provided in the through hole 23.
The conductors 24 from 2 are arranged. Also, shield 2
A conductor 22 connected to the gas insulation device is connected to 1. The gas-partitioning type insulating spacer 20 is attached to the end of the conductor 22. 25 is the conductor 22 described above
The duct 25 is a T-shaped duct with the shield 21 portion of the bushing 9 being substantially at the center. Then, one end thereof is attached to the bushing portion, and the portion branched around the shield portion is connected to the lightning arrester 12. Further, the other end forms a substantially duct-like duct, and the size of the duct of this trapezoidal part is made smaller than the part to which the bushing 9 is attached, and the duct is connected to the gas division type spacer 20.

In this embodiment thus constructed, the following new operation and effect are obtained in addition to the operation and effect obtained in the above-mentioned embodiment. That is, (1) Since the connecting portion between the conductors 22 and 24 is implemented inside the shield 21, electric field concentration does not occur in the T-shaped portion of the conductor, and high breakdown voltage can be achieved. (2) Since the T-shaped portion of the conductor is housed in the shield, the duct 25 becomes shorter than in the conventional case and the above-mentioned embodiment,
For example, even when the lightning arrester fails, the processing time for gas recovery and the like is shortened accordingly, so that recovery is completed in a short time.

[0015]

As described above, according to the present invention, it is possible to provide a transformer having improved insulation reliability and capable of promptly recovering from a lightning arrester accident.

[Brief description of drawings]

FIG. 1 is a schematic view of a connecting portion between a bushing and a lightning arrester of a transformer according to an embodiment of the present invention.

FIG. 2 is a schematic view of a connecting portion between a bushing and a lightning arrester of a transformer according to another embodiment of the present invention.

FIG. 3 is a plan view of one phase of a conventional transformer.

FIG. 4 is a schematic view of a connecting portion of a gas duct attached to the bushing of FIG. 3 and a duct attaching an arrester.

[Explanation of symbols]

1A, 1B ... Unit transformer, 2 ... Tank, 3 ... Iron core, 4 ...
Winding, 5 ... Duct, 6, 9 ... Bushing, 7, 8 ... Lead wire, 10, 13, 15 ... Gas duct, 12 ... Lightning arrester,
14, 20 ... Spacers, 17, 22, 24 ... Conductors, 21
... shield, 23 ... through hole, 25 ... gas tank.

Claims (1)

[Claims] 1. A unit transformer having one phase divided into at least two tanks, and a lead wire having a common electric potential is arranged and taken out from each of the tanks inside a duct attached to the unit transformer. In a transformer in which two lead wires having a common electric potential are connected to a gas duct via an oil / gas separation type bushing attached to the duct, a lightning arrester is connected to the gas duct portion connected via the bushing, and The other part of the gas duct is connected to another gas duct via a gas division spacer, and the size of the gas duct of the part to which the lightning arrester is attached is made larger than the size of the gas duct attached via the gas division spacer. A transformer.