JPH05326292A - Gas insulated transformer - Google Patents

Abstract

PURPOSE:To improve cooling characteristic of a coil by providing within a coil a spacer having the end portion in the shape of streamliner, ellipse or polygon near an ellipse to form a cooling duct. CONSTITUTION:In a gas insulated transformer where a transformer itself formed by winding a coil forming a cooling duct within a winding 9 around an iron core is accommodated in a transformer tank together with the insulation gas and cooling the coil by flowing of the insulation gas cooled by a gas cooling device into the cooling duct 11 within the winding 9, the cooling duct 11 is formed by providing a spacer 14 having the end portion in the shape of streamline or ellipse or polygon near the ellipse within the winding 9. Thereby, a small size transformer ensuring high cooling efficiency and having high reliability can be obtained only by changing the shape of the spacer 14 which forms the cooling duct.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated transformer in which a coil having a cooling duct formed inside a winding is cooled by an insulating gas.

[0002]

2. Description of the Related Art In recent years, as a transformer installed in a substation or the like, a gas-insulated transformer using a gas as an insulating medium is adopted from an oil-filled transformer for disaster prevention reasons. This gas-insulated transformer has various winding configurations, and one of them is a dry type in which the winding is insulated and cooled at the same time.

This dry type gas-insulated transformer is simpler in construction than the semi-pool type or spray type which is constructed in combination with a liquid cooling medium, and the separate type gas-insulated transformer which is separately cooled and insulated. Therefore, it is urgent to develop a large-capacity transformer because it is easy to manufacture a highly reliable one.

There are two types of dry-type gas-insulated transformers, one of which is a sheet coil and the other of which is a wire coil. Here, the case of a sheet coil will be described.

Conventionally, as a winding of a gas-insulated transformer using a sheet coil, a metal sheet and an insulating sheet are superposed and wound as shown in Japanese Patent Publication No. 33-9911.
Grooves that escape in the axial direction are formed by providing elongated spacing pieces (spacers) at appropriate intervals in the winding direction in the winding, and winding cooling gas is allowed to flow through this portion. There is.

FIG. 8 shows an example of a transformer using such a sheet winding. As shown in FIG. 8, the low-voltage coil 3 is wound around the iron core 1 via the insulating tube 2, and the high-voltage coil 5 is coaxially wound on the outer side of the iron core 1 via the insulating tube 4. It is housed in the transformer tank 6 together with the gas. In the low-voltage coil 3 and the high-voltage coil 5, a plurality of sheet windings 9 formed by winding an insulating sheet 7 and a metal sheet 8 are arranged coaxially in multiple layers as shown in FIGS. 9 and 10.
A large number of elongated spacers 10 are inserted into the gaps existing between the sheet windings 9 at equal intervals in the winding direction to form a gas duct 11 that escapes in the winding axis direction.
Also, each sheet winding 9 is supported and fixed by an insulator 12 provided in a plurality of pieces on the lower end surface portion of the high voltage coil 5. Further, a gas cooler 13 is attached to the outer periphery of the transformer tank 6, the insulating gas cooled by the gas cooler 13 flows into the transformer tank 6, and further passes through the gas duct 11 again to the gas cooler 13 again. A gas circulation path is formed back to.

Therefore, in the gas-insulated transformer having such a structure, the insulating gas in the transformer tank 6 cooled by the gas cooler 13 is distributed between the sheet windings 9 forming the low-voltage coil 3 and the high-voltage coil 5. After passing through the gas duct 11 of FIG. 1 to remove the heat generated in each sheet winding 9 to cool it, the sheet is cooled again by the gas cooler 13.

[0008]

However, in such a dry type gas-insulated transformer, the elongated spacers 10 for forming the gas ducts 11 between the sheet windings 9 have a rectangular parallelepiped shape. The insulating gas flowing into the gas duct 11 generates a turbulent flow at the corners of the spacer 10, the insulating gas does not flow smoothly in the gas duct 11, and pressure loss occurs. As a result, if the gas partially stays, a part of the winding is locally heated due to the reduction of the cooling effect, and the deterioration of the insulating material progresses, eventually causing the destruction of the entire transformer.

Therefore, in order to make the insulating gas smoothly flow in the gas duct 11, it is conceivable to increase the opening area of the gas duct 11 or to provide a large-capacity blower in the transformer tank 6. There is a problem that the transformer itself becomes large even if it is shifted. An object of the present invention is to improve the cooling characteristics of a coil in which a cooling duct is formed inside the winding, and to provide a highly reliable small gas-insulated transformer.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a transformer containing a coil having a cooling duct formed inside a winding wound around an iron core in an inside of a transformer tank together with an insulating gas. In a gas-insulated transformer in which an insulating gas housed in a coil and cooled by a gas cooler is caused to flow through a cooling duct inside the winding to cool the coil, the end shape is streamlined or elliptical. Alternatively, a cooling duct is formed by providing a spacer having a polygonal shape close to an ellipse inside the winding.

[0011]

[Operation] In the gas-insulated transformer having such a configuration,
When the insulating gas cooled by the gas cooler flows through the cooling duct formed inside the winding, it flows along the streamlined or elliptical or polygonal shape close to the ellipse formed at the end of the spacer. Therefore, the flow becomes a laminar flow with less turbulent flow, and a large amount of insulating gas can be flowed with a small pressure loss, and the heat exchange rate inside the coil can be increased and local heating of the coil occurs. Can be prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The overall structure of the gas insulation transformer is shown in Fig. 8.
Therefore, the description thereof will be omitted, and only the configuration of different parts will be described here.

In this embodiment, as shown in FIG. 1, a spacer 14 for forming a gas duct 11 extending between the respective sheet windings 9 in the axial direction of the winding is used as a spacer 14 having a slender shape in which both ends are streamlined. This is configured to be arranged at an appropriate interval in the winding direction of the winding.

With such a structure, the insulating gas flowing in each gas duct 11 that escapes in the axial direction of the winding is ducted along the streamline from the lower end of the seat winding 9 to the end of the spacer 14 as shown by the arrow in the figure. It passes through the inside and exits to the upper end side of the sheet winding 9. That is, the gas flow at the lower end of the sheet winding 9 does not generate a vortex even when it hits the spacer 14 forming the gas duct 11, and flows as a laminar flow in the gas duct 11. Therefore, the pressure loss generated when the insulating gas flows decreases, and a large amount of gas flows in the gas duct 11, so that the heat generated from the sheet winding 9 can be effectively taken away.

As a result, the blower for circulating the insulating gas can be downsized, and the opening area of the gas duct 11, that is, the interval and width can be reduced, so that the entire transformer can be downsized. Further, since there is no staying part of the insulating gas, local heating of the sheet winding 9 can be prevented, and the reliability is high. Next, another embodiment of the present invention will be described with reference to FIGS.

In the above embodiment, the spacer 14 has a slender shape in which both ends are processed into a streamlined shape. However, the shape of the ends of the spacer 14 does not need to be a streamlined shape and is shown in FIG. As shown in FIGS. 3 and 4, a spacer processed into a polygonal shape such as a quadrangular shape or a pentagonal shape close to an elliptic shape may be used.

Further, in the above embodiment, the gas duct 11 that escapes in the axial direction of the winding is formed by one spacer 14, but as shown in FIG. 5, two spacers 14a shorter than the winding height are provided in the axial direction. Even if they are arranged side by side, it is possible to obtain the same effects as the above.

Further, when the two spacers 14a shorter than the winding height are arranged in the axial direction of the winding as shown in FIG. 6, the spacers 14a may be arranged at appropriate intervals. Further, as shown in FIG. 7, the upper spacer 14a and the lower spacer 14a may be arranged in a zigzag staggered manner to obtain the same effects as described above.

In each of the above embodiments, the case where the gas duct is constructed by using some of the spacers shown in FIGS. 1 to 7 between the sheet windings has been described, but the present invention is a cylindrical winding using a wire conductor. However, it can be applied in the same manner as described above.

[0020]

As described above, according to the present invention, only by changing the shape of the spacer forming the cooling duct, it is possible to provide a small gas-insulated transformer with good cooling characteristics and high reliability. ..

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a winding portion using a spacer in an embodiment of a gas insulation transformer according to the present invention.

FIG. 2 is a perspective view of a spacer having an elliptical end portion according to another embodiment of the present invention.

FIG. 3 is a perspective view of a quadrangular spacer whose end portion is close to an ellipse according to another embodiment of the present invention.

FIG. 4 is a perspective view of a pentagonal spacer whose end portion is close to an ellipse according to another embodiment of the present invention.

FIG. 5 is a perspective view of a winding portion using a spacer having an elliptical end portion according to another embodiment of the present invention.

FIG. 6 is a perspective view of a winding portion in which an arrangement of spacers having elliptical ends is different according to another embodiment of the present invention.

FIG. 7 is a perspective view of a winding portion in which spacers having elliptical ends are arranged in a zigzag manner in another embodiment of the present invention.

FIG. 8 is a sectional view showing a main part of a conventional gas-insulated transformer.

9 is a bottom view of the winding portion of the transformer of FIG.

10 is a cross-sectional view of a winding portion of the transformer of FIG.

[Explanation of symbols]

1 ... Iron core, 2, 4 ... Insulation cylinder, 3 ... Low-voltage coil, 5
...... High voltage coil, 6 …… Transformer tank, 7 …… Insulation sheet, 8 …… Metal sheet, 9 …… Sheet winding, 111 ……
Gas duct, 12 ... Insulator, 13 ... Gas cooler, 1
4, 14a ... Spacer.

Claims (1)

[Claims] 1. A transformer having a coil having a cooling duct formed in its winding wound around an iron core is housed in a transformer tank together with an insulating gas, and the insulating gas cooled by a gas cooler is supplied. In a gas-insulated transformer, which is designed to flow into a cooling duct inside the winding to cool the coil,
A gas-insulated transformer characterized in that a cooling duct is formed by providing a spacer having a streamlined shape, an elliptical shape, or a polygonal shape close to an elliptic shape at the end inside the winding.