JPS6114713A - Foil wound transformer - Google Patents

Abstract

PURPOSE:To realize the miniaturization of a tank and the mitigation of electric field in multiplication effect by effectively using the space between magnetic shields. CONSTITUTION:Magnetic shiels 8, 8 are installed on the top and the bottom of the external end of a high voltage winding 7 respectively. a narrow metal sheet 14 and a narrow insulation sheet 15 are wound in the space between these two magnetic shields 8, 8 and a winding 16 is completed. Since part of the winding is housed in the space between the magnetic shields 8, 8, the total winding including the magnetic shield 8 can be reduced and this enables the miniaturization of a tank 9. Since the outermost part of the magnetic shield 8 and the outermost circumferene of the winnding are on the same plane, an equipotential line is also on the same plane and the concentration of electric field is effectively reduced than hitherto, so the distance for insulation between the winding 16 and the tank 9 can be reduced and the electric field can drastically be mitigated. Consequently, the electric field can sufficiently mitigated even if a smaller magnetic shield than hitherto is used and in this case, the tank can further be miniaturized.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a foil-wound transformer using a foil-like winding formed by overlappingly winding a metal sheet and an insulating sheet 1 to 1.
In particular, the present invention relates to a foil-wound transformer in which the configuration near the magnetic shield attached to the outer end of the winding has been improved.

[Technical cost of the invention ■] Foil-wound transformers have a good winding space factor and can be made smaller and lighter. It has not been put into practical use with a variable capacity 1'H device. In view of its excellent advantages, efforts are being made to expand its application to higher voltage, for example 275KV, 300MVA class transformers, but the biggest technical challenge is how to increase the cooling capacity. The main issue is whether the winding can have high insulation capacity.

An example of the configuration of such a foil-wound transformer is shown in FIG. That is, an insulating cylinder 2 made of a synthetic resin with high functional strength such as FRP (glass fiber reinforced plastic) is fitted around the outer periphery of the main leg 1 of the iron core, and a metal sheet 1 is fitted around the outer periphery of this insulating cylinder 2.
Low voltage winding 3 made by overlapping and winding ~ and an insulating sheet
is wrapped.

Here, the thickness of the metal sheet used as the foil winding of the high-voltage winding of the high-voltage transformer as described above is extremely thin, ranging from several tens of micrometers to several hundred micrometers.

Cooling ducts 4 are formed in the low J'i winding 3 at appropriate intervals as gaps extending in the stack direction. Furthermore, a reactance gap 5 is provided on the outer periphery of the low FE winding 3.
An insulating cylinder 6 made of synthetic resin or the like is disposed concentrically with the insulating cylinder 2 through the insulating cylinder 6, and a metal sheet and an insulating sheet 1 are overlaid and wound around the outer periphery of the insulating cylinder 6. A high voltage winding 7 is wound thereon.

A cooling duct 4 is also formed in this high If winding 7 by the same means as in the low voltage winding. Furthermore, magnetic shields 8 are provided at both upper and lower ends of the outermost side of the high voltage winding 7.

These windings are all housed in a tank 9, and an insulating medium 10 such as SFB gas or insulating oil also sealed in the tank.
The insulation state of (is ensured by).

In addition, on the upper and lower sides of the low-voltage winding 3 and the high-voltage winding 7,
The grounding object 11 is fixed to the yoke core 12 (A/H)
and an insulator 13 is arranged on the lower grounding object 11,
A low/high voltage winding 3.7 is supported in an insulated state with respect to a yoke core 12 and a grounding object 11.

E Background technology problem white 1 By the way, such an i[! In single-turn transformers, further miniaturization is desired for transportation and installation space considerations such as underground substations, but in conventional foil-wound transformers such as the one described above, The magnetic shield 8, which is pQ +-t applied to alleviate the electric field between the tank 9 and the tank 9, becomes large, making it difficult to downsize the entire winding, and causing the tank 90 of the foil-wrapped diaphragm to have a large hem. was there.

In view of this, if the magnetic shield 8 is reduced in size, electric field concentration will occur around the periphery, which will require a further insulation distance from the tank 9, resulting in an increase in the size of the tank 9.

[Object of the Invention 1 The present invention is directed to the conventional li! This was proposed to eliminate the drawbacks of the I-winding transformer.The purpose of the I-winding transformer was to make effective use of space and to effectively increase the electric field, thereby reducing the size of the tank and reducing the size of the tank. The purpose of the present invention is to provide a foil-wound transformer with high reliability.

[IiI essential points of the invention] -4= fi of the invention! I-volume foundation voltage transformers effectively reduce the electric field by further winding narrow metal sheets and insulating sheets in the space between the magnetic shields placed above and below the outer periphery of the high-voltage winding. It is relaxed and makes effective use of empty space. By making the cross-sectional area of the metal sheet between the magnetic shields equal to or larger than that of the general winding in the central portion, the space factor of the metal sheet in the peripheral portion can be sufficiently maintained.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to FIG.

Note that the same parts as those of the conventional foil-wound transformer shown in FIG.

In this embodiment, magnetic shields 8, 8 are disposed above and below the outer end of the high voltage winding 7, respectively.

In the space between these two magnetic shields 8.8, there is a third
As shown in the figure, a narrowed 1c metal sheet 14 and an insulating sheet 15 are wound to form a winding 16. The cross-sectional area of the metal sheet 14 constituting this winding 16 is the same as or larger than that of the general winding at the center. Further, the outermost circumference of the winding 16 is substantially flush with the outermost surface of the magnetic shield 8.

Note that the other configurations are exactly the same as the prior art shown in FIG.

The action of the foil-wound transformer of this embodiment having the above configuration is as follows.

That is, since a part of the winding is housed in the space between the Ia magnetic shield 8, the entire winding including the magnetic shield 8 can be reduced in size. can be made smaller. In addition, since the outermost part of the magnetic shield 8 and the outermost circumference of the winding lie on the same plane, the equipotential lines are made uniform along this plane, and electric field concentration is reduced more effectively than before. , the insulation distance between the winding 16 and the tank 9 can be reduced, which also helps in miniaturization. Furthermore, since the electric field can be significantly relaxed, the electric field M sum can be sufficiently reduced even if a magnetic shield smaller than the conventional one is used, and in this case, the tank can be further downsized.

The metal sheet 14 constituting the winding 16 of the magnetic shield 8.81M1 has a cross-sectional area equal to or larger than that of the central winding, so it has a certain space factor. However, there are no problems in terms of performance.

[Effects of the Invention] As shown in the above embodiments, according to the present invention, with the configuration that effectively utilizes the space between the magnetic shields, it is possible to synergistically reduce the size of the tank and alleviate the electric field. This has the effect of providing a highly reliable foil-wound transformer.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of a conventional foil-wound transformer, Fig. 2 is a sectional view showing an embodiment of the foil-wound transformer of the present invention, and Fig. 3 shows the main parts of Fig. 2. It is an enlarged sectional view. 1... Main leg of iron core, 2... Insulating tube, 3... Low voltage winding, 4... Cooling duct, 5... Reactance gap, 6... Insulating tube, 7... High Magnetic wire, 8... Magnetic shield, 9... Tank, 10... Insulating medium, 11
...Grounding object, 12...Yoke iron core, 13...Insulator, 14...Metal sheet, 15...Insulating sheet, 1
6... Winding wire. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A foil winding made by overlapping metal sheets and insulating sheets wound around the legs of an iron core is housed in a tank filled with an insulating medium, and magnetic shields are placed above and below the outer end of the high voltage winding. In the installed foil-wound transformer, a metal sheet with a narrower width and an insulating sheet are further layered and wound in the space between the upper and lower magnetic shields, and the cross-sectional area of the metal sheet between the magnetic shields is A foil-wound transformer characterized by being equal to or greater than a general winding.