JPS63291408A - Insulating-gas-filled transformer - Google Patents

Abstract

PURPOSE:To make a tank have a structure which is free from defects in intensity, while minimizing the whole structure of its device and obtain a insulating- gas-filled transformer having the high safety for an internal tension and also having a long lifetime for cyclic operations by causing board thickness reinforcing parts of protruding parts for securing insulating distances as well as an outgoing opening part for taking out leads to be integrated in one or by making each reinforcing part serve a double purpose. CONSTITUTION:Protruding parts 14 of a tank 1 having cross sections of semicircle forms and also having each distance of a constant value from a winding end part 5a are formed at positions facing end parts 5a of a high tension winding 5. An outgoing opening 15 for taking out leads is mounted at a top part of the protruding parts 14. Then, there is a structure where board thickness reinforcing parts 16 of the protruding parts 14 themselves share the board thickness reinforcing part of the opening 15. Thus, a simple structure which allows the reinforcing parts of both the protruding parts and the outgoing opening to be integrated into one improves the intensity of the tank and makes the safety for internal tension high and also a lifetime for cyclic operations long.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention provides an iron core and an internal and external low pressure wound around the iron core in a pressure vessel filled with high pressure insulating gas such as SFa gas. ,
This invention relates to a gas-insulated transformer that houses a transformer body made of high-voltage windings.

(Prior art) In recent years, gas insulated transformers, which have the advantages of being non-flammable and explosion-proof, have been attracting attention in place of oil-immersed transformers.
Small-capacity transformers with relatively low voltages such as V and several tens of MVA have already been put into practical use and are widely used.

Recently, in view of the excellent advantages of such gas insulated transformers,
Higher voltage, larger capacity transformer e.g. 275KV, 300KV
Research is underway to expand its application to MVA class transformers, but the biggest technical challenge in this case is how to improve the cooling capacity of the windings and provide the windings with high insulation capacity. .

The method for cooling the windings in such gas-insulated transformers is to build a cooling duct inside the windings and feed a refrigerant with excellent insulation properties to directly cool the heat generated from winding losses. A heat pipe type is being considered.

FIGS. 6 and 7 show an example of a conventionally known structure of such a gas insulated transformer.

As shown in FIG. 6, tank 1 contains SF as an insulating medium.
An insulating gas such as 6 gas is sealed at high pressure, and an iron core 2 is provided inside the tank 1.

On the outside of the main leg 2a of this iron core 2, low-voltage windings 4 and 5 are wound concentrically inside and outside via an insulating cylinder 3, and insulation is maintained between the two windings by an insulating barrier 6. . Low voltage winding 4
The high-voltage winding 5 is configured as a foil-like winding formed by overlapping and winding a metal sheet 7 made of aluminum foil or the like and an insulating sheet 8 made of resin film or the like.

Further, a cooling duct 9 extending in the axial direction is wound around and built into the low voltage and high voltage windings 4 and 5. The inside of this cooling duct 9 is hollow so that a refrigerant such as Freon 113 or 70 Linate FC75 passes through it. It is designed to circulate through a tube 12 and an insulated pipe 13.

The conventional gas-cooled transformer as explained above is called a separate foil-wound transformer, and this type of transformer is
-4039990 is known.

By the way, in such a conventional gas insulated transformer,
Generally, the dielectric strength of gas increases as the gas pressure increases, so the tank structure of a gas insulated transformer needs to function as a pressure vessel.

Therefore, generally, as shown in FIG. 7 (A>(B)),
It is common to have a cylindrical tank body 1a and an end plate 1b. In addition, recently, a tank structure has been developed in which a part of the tank 1 has an outward protrusion 14 in order to provide a sufficient insulation distance from the high-voltage winding 5 on the outer periphery while reducing the size of the tank. It is widespread. Generally speaking, the tank 1 has an opening 15 for leading out the leads of the high-voltage and low-voltage windings 4 and 5. At the edges of such protrusions 14 and lead drawer openings 15, in accordance with pressure vessel standards, plate thickness reinforcement parts are made with increased plate thickness in order to reinforce the strength that decreases due to protrusions and openings. 16.17 is required.

By the way, in such a tank structure, the protrusion 1
4 and drawer opening 15 are close to each other due to the arrangement of the leads. When loaded, the condition of discontinuity in plate thickness on the tank wall has a synergistic effect, resulting in stress concentration, which becomes a weak point in the strength of the tank structure.Also, it is difficult to resist internal pressure fluctuations due to temperature rise during transformer operation. There is a problem of shortened fatigue life.

(Problems to be Solved by the Invention) As described above, in conventional gas insulated transformers whose tanks have protrusions and drawer openings for ensuring insulation distance, the strength between the protrusions and the openings is high. There were some problems and weaknesses.

The present invention was proposed to solve these problems, and its purpose is to reduce the size of the entire device while creating a tank structure that does not have any strength defects. It is an object of the present invention to provide a gas insulated transformer that is highly safe against internal pressure and has a long repeated life.

[Structure of the Invention] (Means for Solving the Problems) The gas insulated transformer according to the present invention has a protrusion in a portion facing the end of the high-voltage winding of the tank, and a lead drawer in the vicinity of the protrusion. The structure is characterized in that a drawer opening is provided, and the plate thickness reinforcing part of the protruding part and the plate thickness reinforcing part of the drawer opening are integrated or used together.

(Function) In the present invention having the above configuration, the plate thickness reinforcing part of the protruding part for ensuring the insulation distance and the plate thickness reinforcing part of the drawer opening for drawing out the lead can be integrated or used together. This solves the problem of discontinuity in plate thickness on the tank wall, making it possible to create a tank structure without any weak points in terms of strength.

(Example) Hereinafter, one example of the gas insulated transformer according to the present invention will be specifically described using the drawings. Note that the same parts as in the prior art shown in FIGS. 6 and 7 are designated by the same reference numerals, and the explanation thereof will be omitted.

Configuration of this embodiment* In the embodiment shown in FIG. A protrusion 14 having a semicircular cross section with a distance is formed.A drawer opening 15 for pulling out the lead is provided at the top of the protrusion 14.Thus, the thickness reinforcement part 16 of the protrusion 14 is the opening 15 as it is.
The structure also serves as a reinforcing section.

Effects of this embodiment* The effects of this embodiment having the above-described configuration are as follows.

First, FIG. 2 (A> is a perspective view showing a part of the conventional technology shown in FIGS. 6 and 7. Pressure is applied to this conventional tank structure, and FIG. A> Middle official - part of the official (
Dimensional stress (stress/yield strength) generated around the reinforced part of the plate
is shown in FIG. 2(B).

As shown in Figure 2 (B), in a conventional tank structure with a plate thickness normally designed based on pressure vessel standards, dimensionless stress is generated at the plate thickness reinforcement part '17.16 at the frontage. is about 0.3 to 0.4, while the dimensionless stress in the general part sandwiched between both reinforcing parts is about 0.9 to 1.
It has even reached 0. This is due to the concentration of stress generated from the discontinuity in plate thickness acting at the crotch.

On the other hand, FIG. 3 (A) is a perspective view showing a part of the present embodiment shown in FIG. 1 (A>(B)). Figure 2 (A>Nakaai-Aiichi,
Non-dimensional stress (
stress/yield strength) is shown in FIG. 3(B).

As shown in Figure 3 (B) middle ■, there is a love for this example.
The dimensionless stress distribution along the axial and axial sections can be reduced to about 0.5 at most, which is about half of the yield stress. Therefore, the safety factor against internal pressure breakdown of the tank 1 is improved to approximately twice that of the conventional system. Furthermore, it has been revealed that the fatigue life against internal pressure fluctuations due to temperature rise during operation is approximately 10 times longer according to this embodiment.

*Other Examples* It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, Fig. 4 (A) (B) and Fig. 5 (A>(B)
The following embodiments can be considered.

In the embodiment shown in FIG. 4 <A> (8), the lead extraction opening 15 is attached to the axial end of the protrusion 14 of the tank 1, and the stress level of this embodiment is as shown in FIG. 3. (B)
As shown in middle (2), the stress is slightly larger than that of Example (2), but it is still within half of the yield stress.

Further, in the embodiment shown in FIG. 5 (A>(B)), the plate thickness reinforcement part of the protruding part 14 and the opening part 15 are integrated to form a plate thickness reinforcement part 19, and the stress distribution of this embodiment is As shown in Figure 2 (B), it has been found that the yield capacity is within half of the yield response capacity.

[Effects of the Invention] As explained above, according to the present invention, the strength of the tank can be significantly improved compared to the conventional structure by simply improving the structure of integrating the protruding portion and the reinforcing portion of the drawer opening. Therefore, it is possible to provide an excellent gas insulated transformer that is highly safe against internal pressure and has a long cycle life.

[Brief explanation of the drawing]

FIG. 1 (A>(B) is a front view and cross-sectional view showing a first embodiment of a gas insulated transformer according to the present invention, and FIG. 2 (A> is a front view showing a part of a conventional gas insulated transformer. Figure, Figure 2 (
B) is a graph showing the stress distribution of the conventional example of FIG. 2 (A>) and the third embodiment of the present invention, and FIG. FIG. 3(B) is the first embodiment of the present invention.
Graph showing each response force distribution of the example and the second example, 4th
Figures (A>(B) are front views and cross-sectional views showing the second embodiment of the present invention, and Figures (A>(B) are front views and cross-sectional views showing the third embodiment of the present invention. Figure 6 is a sectional view showing a conventional gas insulated transformer, and Figure 7 (A>(B) is the same (a front view and a sectional view showing a conventional gas insulated transformer). 1...Tank, 1a ...Tank body, 1b...Tank end plate, 2...Iron core, 3...Insulation tube, 4...Low voltage winding, 5...High voltage winding, 6...Insulation barrier, 7・
...Metal sheet, 8...Insulating sheet, 9...Cooling duct, 10...Cooler, 11...Pump, 12...
・Liquid guide pipe, 13... Insulated pipe, 14... Protrusion part,
15... Drawer opening, 16... Plate thickness reinforcement part of protruding part, 17... Plate thickness reinforcement part of drawer opening, 18...
Tank wall between protrusion and drawer opening, 19...integrated plate thickness reinforcement part.

Claims (2)

[Claims] (1) A transformer body consisting of an iron core and internal and external low-voltage and high-voltage windings wrapped around the iron core is housed in a cylindrical pressure vessel filled with insulating gas pressurized to a predetermined pressure. In the gas insulated transformer, a protrusion protruding to the outside of the tank is formed at a portion of the tank wall facing the end of the high-voltage winding, and a drawer opening for leading out the lead is provided near the protrusion. 1. A gas insulated transformer characterized in that a plate thickness reinforcing part of the section and a plate thickness reinforcing part of the drawer opening are integrated or used together. (2) The gas insulated transformer according to claim 1, wherein the drawer opening for drawing out the lead is provided on the protrusion.