JP2575980B2 - Split type transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a split type transformer,
In particular, a large-capacity, high-voltage transformer divides a one-phase transformer into at least two parts, takes out a lead having a common potential from each transformer, connects the lead to a bushing,
The other end of the bushing relates to a transformer duct structure connected to a lead in a gas insulated duct.

[0002]

2. Description of the Related Art In recent years, prices of urban land have risen,
Power supply sites, such as power plants, are often constructed in locations far from power demanding sites. Recently, UHV power transmission has been studied as such power transmission from a remote distance. UHV
Substations for transmission will be located in the mountains. Transformers used in such substations are conventionally manufactured within strict transportation restrictions. However, since the voltage is high and the capacity is large, a transformer in which a three-phase transformer is divided into six is being studied. An example of such a transformer for one phase is shown in FIG.

In FIG. 3, unit transformers 1A and 1B constituting a single-phase transformer are juxtaposed in parallel so that their longitudinal tanks 23 face each other, and are covered with a soundproof wall 4. I have. Each of the unit transformers 1A and 1B is composed of a tank 23, an iron core 24 installed in the tank 23, and a winding 25 wound around the main leg of the iron core 24. The high-voltage lead 14 and the medium-voltage lead 15 of each of the unit transformers 1A, 1B are connected via a substantially T-shaped duct from a position at substantially the same height on the side of the tank 23 of each of the unit transformers 1A, 1B facing each other. The high pressure bushing 16 and the medium pressure bushing 17 are connected to one end.

The load voltage regulators 3A, 3B attached to the unit transformers 1A, 1B are connected to the load voltage regulator connection duct units 2A, 2A, 3B in the short direction of the tank 23 of each unit transformer 1A, 1B.
Each is connected via 2B.

FIG. 3 is a diagram showing a case in which three single-phase transformers shown in FIG. 2 are arranged to form a three-phase transformer. A single-phase transformer U constituted by two unit transformers 1A and 1B, and similarly, single-phase transformers V and W constituted by single-phase transformers 1C, 1D, 1E and 1F are respectively disposed in the longitudinal direction of the tank 23. High-pressure bushing 16 and medium-pressure bushing 17 with the side faces facing each other
Are arranged in the same direction in opposite directions to each other and are juxtaposed to constitute a three-phase transformer. The high-voltage line, the medium-voltage line, and the transformer are connected by gas-insulated buses 26 and 27. The high-pressure bushing 16 and the high-pressure gas-insulated bus 26, and the medium-pressure bushing 17 and the medium-pressure gas-insulated bus 27 are connected. ing. These gas-insulated buses 26 and 27 are connected to other substation equipment at the end opposite to the transformer. By the way, the conventional split type three-phase transformer configured as described above has the following problems.

[0006]

As described above, the duct from the transformer and the gas-insulated bus are connected via the bushing. The gas-insulated bus is connected to the substation equipment.

Conventionally, the size (diameter) of the duct from the transformer and the gas-insulated bus has been the same. The reason is that the distance between the gas-insulated substation equipment and the transformer is short and directly connected. However, in the UHV class, the distance between the transformer and the gas insulation device becomes longer.
This is because the substation is mounted in a mountainous area, and it is difficult to secure a large plane at the same place. For this reason, the gas-insulated substation equipment and the transformer are often installed not on the same plane but on separate planes. As described above, when the length of the gas-insulated bus is long, it is desired to minimize the size of the gas-insulated bus from both the ground and the cost. As one means for achieving this, there is a method in which, for example, a trumpet-shaped gas-insulated bus is attached at one position in the middle of the gas-insulated bus, and the size of the gas-insulated bus thereafter is reduced. However, this method requires the installation of a trumpet-shaped gas-insulated bus in the middle, which not only increases the number of connection points, but also creates a trumpet-shaped tank that can withstand high gas pressure. It is. Further, when such a trumpet-shaped gas-insulated bus is manufactured and attached in the middle of the bus, the electric field on the ground side and the lead wire of the gas-insulated bus is not uniform because the voltage of the gas-insulated bus is constant. Therefore, if impurities intrude into the gas-insulated bus, they will collect in the portion where the electric field has changed, and the insulation reliability of that portion will be reduced. Furthermore, since the size of the gas-insulated bus changes on the way, the cooling from the gas bus surface is not constant and changes at the connection part.
A temperature gradient occurs in the insulating spacer that supports and insulates the high-voltage conductor attached to the connection portion, and a stress is generated due to expansion and contraction of the spacer. Therefore, the insulation reliability and mechanical reliability of the insulating spacer attached to the connection portion may be reduced.

The present invention has been made in view of the above points, and has as its object to connect a duct from a transformer to a bushing and a gas-insulated bus, and to change the size of the gas-insulated bus from the middle. And to provide a reliable split type transformer.

[0009]

In the present invention, a duct from a transformer is mounted on a bushing, and the size of the mounting flange of the bushing is different between the duct side and the gas-insulated bus side, and the size of the flange is changed. The gas-insulated bus side is made smaller, and a gas-insulated bus having a diameter smaller than the size of the duct from the transformer is connected thereto.

[0010]

As described above, according to the present invention, the size of the gas-insulated bus is constant from the bushing portion of the transformer until the size of the gas-insulated bus is connected to the gas-insulated substation equipment. In addition, the temperature gradient is eliminated, and the insulation reliability and mechanical reliability of the insulating spacer attached thereto are improved, so that a reliable split type transformer can be obtained. Furthermore, since the diameter is not changed in the middle of the gas-insulated bus, a trumpet-shaped high gas pressure tank is not required. Further, since the electric field is uniform at the gas-insulated bus, insulation reliability is also improved.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. The same parts as those in the related art are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 shows an outline of a duct from a transformer, a bushing connected to the transformer, and a gas-insulated bus as an embodiment of the present invention. In FIG. 1, reference numeral 31 denotes a duct in which a high-voltage lead or an intermediate-voltage lead connected to a divided transformer is connected. Reference numeral 32 denotes a high-pressure or medium-pressure bushing, and the bushing 32 has flanges 33 and 34 attached thereto.
Reference numeral 35 denotes a gas-insulated busbar, which is fixed between the bushing 32 and the flange 34 attached thereto.
Reference numeral 36 denotes a conservator that absorbs expansion and contraction of oil in the bushing 32. The flange of the bushing described above is thinner on the gas-insulated bus side than on the transformer side.
In addition, the duct 31 and the gas-insulated bus 35
Is smaller in the gas-insulated bus.

In the embodiment of the present invention configured as described above, the following operational effects are obtained. In other words, the size of the gas-insulated bus connected to the split-type transformer does not change its diameter during the connection to the gas-insulated equipment. The gradient is eliminated, the insulation reliability and mechanical reliability of the insulating spacer attached thereto are improved, and a reliable split-type transformer is obtained. Furthermore, since the diameter is not changed in the middle of the gas-insulated bus, a trumpet-shaped high gas pressure tank is not required. Further, since the electric field is uniform at the gas-insulated bus, insulation reliability is also improved.

Furthermore, the size of the flange to be attached to the bushing can be changed only by changing the size of the gas-insulated bus and the duct.
Since the dimensions of the gas-insulated bus and the duct can be changed, not only is the dimensional change of the gas-insulated bus easy, but also as described above, a trumpet shape is used when the size of the gas-insulated bus is changed in the middle of the gas-insulated bus. Gas tank is unnecessary, and an inexpensive split transformer can be obtained. Furthermore, even when assembling the transformer on site, the diameter does not need to be reduced in the middle of the gas insulated bus, and the on-site assembly time can be reduced.

[0014]

As described above, according to the present invention, the size of the flange of the bushing connected to the duct is changed, and a gas-insulated bus bar having a diameter smaller than that of the duct is connected to the bush, thereby achieving a reliable division. A type transformer is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a duct, a bushing, and a gas-insulated bus from a split-type transformer according to an embodiment of the present invention.

FIG. 2 is a plan view showing a split transformer.

FIG. 3 is a diagram showing a three-phase transformer in which three divided single-phase transformers are collectively arranged for one bank.

[Explanation of symbols]

 14 ... High pressure lead 15 ... Medium pressure lead 23 ... Tank 31 ... Duct 32 ... Bushing 33, 34 ... Flange 35 ... Gas insulated bus

Claims (1)

(57) [Claims] 1. A plurality of unit transformers having a tank, an iron core disposed in the tank, and a plurality of parallel-connected high-voltage windings and medium-voltage windings wound around the iron core. The high-voltage winding and the medium-voltage winding of the unit transformer are respectively connected by a high-voltage lead and a medium-voltage lead, from the tank to a high-pressure duct,
In the split type transformer, which is drawn into the medium pressure duct and connected to the bushing, and the other end of the bushing is connected to the lead wire inside the gas insulating duct, the duct from the transformer and the gas insulating duct Wherein the diameter of the duct from the transformer is larger than the diameter of the gas-insulated duct.