阅读说明：本技术 一种低局部放电的干式变压器 (Low partial discharge's dry-type transformer ) 是由 张军海 叶彪 郭敬旺 莫向松 彭景伟 廖平新 张绮雯 叶晓锋 孔令斌 唐永烁 于 2021-06-10 设计创作，主要内容包括：本发明提供了一种低局部放电的干式变压器,包括铁芯,铁芯包括上铁轭、下铁轭及设置于上铁轭和下铁轭之间的芯柱；第一绝缘层,套设置于芯柱上；第二绝缘层,设置第一绝缘层外；绕组,绕组包括线材和树脂封装层,线材绕设于第一绝缘层和第二绝缘层之间,树脂封装层渗入线材的匝间间隙和层间间隙,将绕组固化为一体,线材包括线芯和包覆于线芯上的真空浸渍树脂薄膜。通过在线芯的表层设置真空浸渍树脂薄膜,不易形成气隙或者气泡,减少线材上的气泡,同时,能够轻易筛除具有气隙或者气泡的线材,线材上的真空浸渍树脂薄膜与树脂封装层具有良好的相融性,最终,减少固化成一体的绕组内的气隙或者气泡,降低及减少局部放电。(The invention provides a low partial discharge dry-type transformer, which comprises an iron core, wherein the iron core comprises an upper iron yoke, a lower iron yoke and a core column arranged between the upper iron yoke and the lower iron yoke; the first insulating layer is sleeved on the core column; the second insulating layer is arranged outside the first insulating layer; the winding comprises a wire and a resin packaging layer, the wire is wound between a first insulating layer and a second insulating layer, the resin packaging layer penetrates into inter-turn gaps and interlayer gaps of the wire to solidify the winding into a whole, and the wire comprises a wire core and a vacuum impregnation resin film coated on the wire core. The vacuum impregnation resin film is arranged on the surface layer of the wire core, so that air gaps or air bubbles are not easily formed, the air bubbles on the wire rod are reduced, meanwhile, the wire rod with the air gaps or the air bubbles can be easily screened out, the vacuum impregnation resin film on the wire rod and the resin packaging layer have good compatibility, finally, the air gaps or the air bubbles in the winding which is integrally solidified are reduced, and partial discharge is reduced and reduced.)

1. A low partial discharge dry transformer, comprising:

the iron core comprises an upper iron yoke, a lower iron yoke and a core column arranged between the upper iron yoke and the lower iron yoke;

the first insulating layer is sleeved on the core column;

the second insulating layer is arranged outside the first insulating layer;

the winding comprises a wire and a resin packaging layer, the wire is wound between the first insulating layer and the second insulating layer, the resin packaging layer penetrates into inter-turn gaps and interlayer gaps of the wire to solidify the winding into a whole, and the wire comprises a wire core and a vacuum impregnation resin film coated on the wire core.

2. A low partial discharge dry transformer as claimed in claim 1 wherein: the low partial discharge dry-type transformer further includes a first elastic insulation layer disposed between the winding and the first insulation layer, and a second elastic insulation layer disposed between the winding and the second insulation layer.

3. A low partial discharge dry transformer as claimed in claim 2 wherein: the first elastic insulating layer and the second elastic insulating layer are both silicone rubber layers.

4. A low partial discharge dry transformer as claimed in claim 2 wherein: the low partial discharge dry transformer comprises two of the windings;

the first winding is a low-voltage winding, the corresponding first insulating layer is an inner insulating cylinder, and the corresponding second insulating layer is an intermediate insulating cylinder;

the other winding is a high-voltage winding, the corresponding first insulating layer is a middle insulating cylinder, and the corresponding second insulating layer is an outer insulating cylinder.

5. A low partial discharge dry transformer as claimed in claim 4 wherein: the first elastic insulating layer corresponding to the low-voltage winding is a low-voltage inner elastic insulating layer, and the second elastic insulating layer corresponding to the low-voltage winding is a low-voltage outer elastic insulating layer;

the first elastic insulating layer corresponding to the high-voltage winding is a high-voltage inner elastic insulating layer, and the second elastic insulating layer corresponding to the high-voltage winding is a high-voltage outer elastic insulating layer.

6. A low partial discharge dry transformer as claimed in claim 1 wherein: a grid cloth layer is arranged in the turn-to-turn gap of the coil formed by winding the wire; or

A gridding cloth layer is arranged in the interlayer gap of the coil formed by winding the wire rod; or

And the turn-to-turn gaps of the coil formed by winding the wire rods are provided with grid cloth layers.

7. A low partial discharge dry transformer as claimed in claim 6 wherein: the wire further comprises a grid cloth layer coated on the surface layer of the vacuum impregnation resin film.

8. A low partial discharge dry transformer as claimed in claim 7 wherein: the grid cloth layer is glass fiber grid cloth.

9. A low partial discharge dry transformer as claimed in claim 1 wherein: and when the winding is a high-voltage winding, a metal shielding layer is further arranged on the second insulating layer.

10. A low partial discharge dry transformer as claimed in claim 1 wherein: the softening point temperature of the vacuum impregnation resin film is higher than that of the resin packaging layer.

Technical Field

The invention relates to a transformation device, in particular to a dry-type transformer with low partial discharge.

Background

As one of the most important electrical devices of a grid system, the proper operation of a power transformer is of critical importance. According to the statistical data of the troubleshooting conditions of the fault hidden trouble of the power system, the insulation fault is an important reason influencing the normal operation function of the transformer, and the partial discharge is the key point of causing the insulation fault of the transformer. The air gap in the insulating layer of the dry type transformer leads to the enhancement of partial discharge, and the partial discharge corrodes and destroys the insulating layer for a long time, thereby shortening the service life of the dry type transformer.

Disclosure of Invention

In order to overcome the defects of the prior art, an object of the present invention is to provide a dry-type transformer with low partial discharge, so as to solve the technical problem that the service life of the dry-type transformer in the prior art is shortened due to the influence of the partial discharge.

One of the purposes of the invention is realized by adopting the following technical scheme:

a low partial discharge dry transformer comprising:

the iron core comprises an upper iron yoke, a lower iron yoke and a core column arranged between the upper iron yoke and the lower iron yoke;

the first insulating layer is sleeved on the core column;

the second insulating layer is arranged outside the first insulating layer;

the winding comprises a wire and a resin packaging layer, the wire is wound between the first insulating layer and the second insulating layer, the resin packaging layer penetrates into inter-turn gaps and interlayer gaps of the wire to solidify the winding into a whole, and the wire comprises a wire core and a vacuum impregnation resin film coated on the wire core.

Optionally, the low partial discharge dry-type transformer further includes a first elastic insulation layer disposed between the winding and the first insulation layer, and a second elastic insulation layer disposed between the winding and the second insulation layer.

Optionally, the first elastic insulating layer and the second elastic insulating layer are both silicone rubber layers.

Optionally, the low partial discharge dry transformer comprises two of the windings;

the first winding is a low-voltage winding, the corresponding first insulating layer is an inner insulating cylinder, and the corresponding second insulating layer is an intermediate insulating cylinder;

the other winding is a high-voltage winding, the corresponding first insulating layer is a middle insulating cylinder, and the corresponding second insulating layer is an outer insulating cylinder.

Optionally, the first elastic insulation layer corresponding to the low-voltage winding is a low-voltage inner elastic insulation layer, and the second elastic insulation layer corresponding to the low-voltage winding is a low-voltage outer elastic insulation layer;

the first elastic insulating layer corresponding to the high-voltage winding is a high-voltage inner elastic insulating layer, and the second elastic insulating layer corresponding to the high-voltage winding is a high-voltage outer elastic insulating layer.

Optionally, a space between turns of the coil wound by the wire is provided with a mesh layer; or

A gridding cloth layer is arranged in the interlayer gap of the coil formed by winding the wire rod; or

And the turn-to-turn gaps of the coil formed by winding the wire rods are provided with grid cloth layers.

Optionally, the wire further comprises a mesh fabric layer coated on the surface layer of the vacuum-impregnated resin film.

Optionally, the scrim layer is a fiberglass scrim.

Optionally, when the winding is a high-voltage winding, a metal shielding layer is further disposed on the second insulating layer.

Optionally, the softening point temperature of the vacuum-impregnated resin film is higher than the softening point temperature of the resin encapsulation layer.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the vacuum impregnation resin film is arranged on the surface layer of the wire core, so that air gaps or air bubbles are not easy to form, the air bubbles on the wire rod are reduced, meanwhile, the wire rod with the air gaps or air bubbles can be easily screened out, the vacuum impregnation resin film on the wire rod and the resin packaging layer have good compatibility, finally, the air gaps or air bubbles in the integrally solidified winding are reduced, and partial discharge is reduced.

Drawings

Fig. 1 is a schematic structural view of a low partial discharge dry type transformer of the present invention;

fig. 2 is a partial structural view of a low partial discharge dry type transformer according to the present invention;

fig. 3 is a schematic half-sectional view of a low partial discharge dry type transformer of the present invention.

In the figure:

1. a stem; 2. a first insulating layer; 3. a second insulating layer; 4. a winding; 41. a wire rod; 411. a wire core; 412. empty impregnated resin film; 413. a mesh fabric layer; 42. a resin encapsulation layer; 5. a first elastic insulating layer; 6. a second elastic insulating layer; 8. a metal shielding layer;

2a, an inner insulating cylinder; (ii) a 3a, an outer insulating cylinder; 7a, an intermediate insulating cylinder; 4a, a low-voltage winding; 4b, high-voltage winding; 5a, a low-voltage inner elastic insulating layer; 6a, a low-voltage outer elastic insulating layer; 5b, high-voltage inner elastic insulating layers; 6b, high-voltage outer elastic insulating layer.

Detailed Description

The present invention is further described with reference to fig. 1 to 3 and the detailed description thereof, and it should be noted that, in the case of no conflict, any combination between the embodiments or technical features described below may form a new embodiment.

As shown in fig. 1 and 2, the present invention provides a low partial discharge dry type transformer including a core, a first insulating layer 2, a second insulating layer 3, and a winding 4. The iron core comprises an upper iron yoke, a lower iron yoke and a core column 1 arranged between the upper iron yoke and the lower iron yoke; the first insulating layer 2 is sleeved on the core column 1, and the second insulating layer 3 is arranged outside the first insulating layer 2; the winding 4 includes a wire 41 and a resin encapsulation layer 42, and the wire 41 is wound between the first insulation layer 2 and the second insulation layer 3, thereby forming a coil. The resin sealing layer 42 penetrates the inter-turn gaps and the inter-layer gaps of the wire 41, and cures the coil into a unit to form the winding 4, and the wire 41 includes a core 411 and a vacuum-impregnated resin film 412 covering the core 411.

When the coil 4 is resin-cured, some of the methods are to directly cure the coil wound by the core 411, thereby obtaining an integrally cured coil 4. In this way, on one hand, since the surface layer of the wire core 411 itself is not completely smooth, for example, pits exist on the surface layer of the wire core 411, and the existence of the pits makes air gaps or air bubbles easily appear in the resin curing process; on the other hand, when the wire core 411 is directly cured by resin, the liquid resin and the surface of the wire core 411 have material difference, and the liquid resin and the wire core 411 have poor compatibility, so that air gaps or air bubbles are easily formed on the surface layer of the wire core 411; on the other hand, the wire core 411 is directly solidified into the winding 4, so that an air gap or air bubbles inside the wire core are difficult to find, and the winding 4 with the air bubbles inside the wire core is difficult to screen. In order to avoid the foregoing problem, in the present embodiment, the wire 41 includes the wire core 411 and the vacuum-impregnated resin film 412, and by forming the vacuum-impregnated resin film 412 on the surface layer of the wire core 411 by a vacuum impregnation process, the air gaps or air bubbles are more easily broken when the surface layer of the wire core 411 has the air gaps or air bubbles after being impregnated into the film than when the wire core 411 is directly cured into a whole, and the liquid resin can fill the air gaps or air bubbles under a vacuum condition, thereby reducing the number of the air gaps or air bubbles. Especially after the second impregnation, air voids or bubbles can be reduced considerably.

In a step of reduction, even after the vacuum impregnation resin film 412 is formed on the surface layer of the core 411, bubbles still exist, the surface layer of the wire 41 is a film, and there is a difference between the position of the air gap or the bubble and the normal position in shape and color, so that the wire 41 with the air gap or the bubble is easily screened out, thereby reducing or avoiding the wire 41 with the air gap or the bubble on the surface of the core 411 from entering a subsequent curing and packaging process, reducing the air gap or the bubble after curing into a whole, and reducing partial discharge.

The material quotient of the vacuum-impregnated resin film 412 is the same as or similar to that of the resin encapsulation layer 42, and when the resin is cured and encapsulated, the vacuum-impregnated resin film 412 and the resin encapsulation layer 42 have good compatibility at high temperature, so that air gaps or air bubbles can be reduced or avoided.

Therefore, by disposing the vacuum-impregnated resin film 412 on the surface layer of the core 411, air gaps or air bubbles are not easily formed, air bubbles on the wires 41 are reduced, and the wires 41 with air gaps or air bubbles can be easily screened out, so that the vacuum-impregnated resin film 412 on the wires 41 and the resin encapsulation layer 42 have good compatibility, and finally, the air gaps or air bubbles in the integrally cured winding 4 are reduced, and partial discharge is reduced.

In some embodiments, as shown in fig. 1 and 2, the low partial discharge dry-type transformer further includes a first elastic insulation layer 5 and a second elastic insulation layer 6, the first elastic insulation layer 5 is disposed between the winding 4 and the first insulation layer 2, and the second elastic insulation layer 6 is disposed between the winding 4 and the second insulation layer 3. The winding 4 is vacuum-cast with resin to be solidified into a whole, after the winding 4 is solidified and cooled, a gap exists between the winding 4 and the first insulating layer 2 positioned on the inner side of the winding 4, so that an air gap is formed, and a gap exists between the winding 4 and the second insulating layer 3 positioned on the outer side of the winding 4, so that an air gap is formed. In this embodiment, the first elastic insulating layer 5 is disposed between the winding 4 and the first insulating layer 2, and the second elastic insulating layer 6 is disposed between the winding 4 and the second insulating layer 3, and due to the elasticity of the first elastic insulating layer 5 and the second elastic insulating layer 6, when the winding 4 is cured and contracted, the first elastic insulating layer 5 and the second elastic insulating layer 6 are extended, so as to fill a gap generated when the winding 4 is contracted, thereby preventing an air gap from being generated.

In some embodiments, the first and second elastic insulation layers 5, 6 are both silicone rubber layers. The silicon rubber has good insulativity and elasticity, and the first elastic insulating layer 5 and the second elastic insulating layer 6 are made of silicon rubber, can adapt to the working environment and play the functions of insulation and extension.

In some embodiments, as shown in fig. 3, the low partial discharge dry transformer comprises two windings 4.

One winding 4 is a low-voltage winding 4a, the corresponding first insulating layer 2 is an inner insulating cylinder 2a, and the corresponding second insulating layer 3 is an intermediate insulating cylinder 7 a; the other winding 4 is a high voltage winding 4b, the corresponding first insulating layer 2 is an intermediate insulating cylinder 7a, and the corresponding second insulating layer 3 is an outer insulating cylinder 3 a. In this way, the dry-type transformer has an inner insulating cylinder 2a, a low-voltage winding 4a, an intermediate insulating cylinder 7a, a high-voltage winding 4b, and an outer insulating cylinder 3a in this order from inside to outside, and three insulating cylinders having a cylindrical structure separate the low-voltage winding 4a and the high-voltage winding 4b to form an insulating environment.

In some embodiments, as shown in fig. 3, the first elastic insulation layer 5 corresponding to the low voltage winding 4a is a low voltage inner elastic insulation layer 5a, and the second elastic insulation layer 6 corresponding to the low voltage winding 4a is a low voltage outer elastic insulation layer 6 a.

The first elastic insulation layer 5 corresponding to the high-voltage winding 4b is a high-voltage inner elastic insulation layer 5b, and the second elastic insulation layer 6 corresponding to the high-voltage winding 4b is a high-voltage outer elastic insulation layer 6 b.

In this way, the dry-type transformer has a structure including, in order from the inside to the outside, an inner insulating cylinder 2a, a low-voltage inner elastic insulating layer 5a, a low-voltage winding 4a, a low-voltage outer elastic insulating layer 6a, an intermediate insulating cylinder 7a, a high-voltage inner elastic insulating layer 5b, a high-voltage winding 4b, a high-voltage outer elastic insulating layer 6b, and an outer insulating cylinder 3 a. The low-voltage inner elastic insulating layer 5a and the low-voltage outer elastic insulating layer 6a respectively extend to fill gaps on the inner side and the outer side of the low-voltage winding 4a, and the high-voltage inner elastic insulating layer 5b and the high-voltage outer elastic insulating layer 6b respectively extend to fill gaps on the inner side and the outer side of the high-voltage winding 4b, so that air gaps in the dry-type transformer are greatly reduced, and partial discharge is reduced or reduced.

After the wire 41 is wound into a coil, spaces with smaller entrances are formed in the coil, and an air gap or air gap is more easily formed in the coil due to the smaller entrances of the spaces.

In some embodiments, the inter-turn gaps of the coil around which wire 41 is wound are provided with a scrim layer 413. In this embodiment, the scrim layer 413 is disposed at the inter-turn gaps, and the scrim layer 413 directs the flow of liquid resin during the vacuum resin casting process to better fill various areas within the coil and reduce or avoid air gaps or bubbles.

In some embodiments, the interlaminar spaces between the wires 41 around the finished coil are provided with a scrim layer 413, and the scrim layer 413 directs the flow of liquid resin during the vacuum resin casting process to better fill various areas within the coil and reduce or avoid air gaps or bubbles.

In some embodiments, the inter-turn gaps and inter-turn gaps of the coil around which wire 41 is wound are provided with mesh cloth layer 413, and mesh cloth layer 413 directs the flow of liquid resin during the vacuum resin casting process to better fill various areas within the coil and reduce or avoid air gaps or bubbles.

In some embodiments, as shown in fig. 3, the wire 41 further includes a mesh fabric layer 413 covering the surface of the vacuum-impregnated resin film 412. In the vacuum resin casting process, the scrim layer 413 directs the flow of liquid resin to better fill various areas within the coil, reducing or avoiding air gaps or bubbles. In addition, the mesh fabric layer 413 covers the vacuum-impregnated resin film 412, so that the state resin can flow around the wire 41 and can more easily flow into the space inside the coil, and air gaps and air bubbles can be more effectively reduced or avoided.

In some embodiments, the scrim layer 413 is a fiberglass scrim, which has good insulating effect.

In some embodiments, as shown in fig. 3, when the winding 4 is a high-voltage winding 4b, the second insulating layer 3 is further provided with a metal shielding layer 8, i.e. the outer insulating cylinder 3a is provided with the metal shielding layer 8. By arranging the metal shielding layer 8 to balance the electric field, the phenomenon of local strong discharge caused by over-strong local electric field is avoided.

The second insulating layer 3 is further provided with a metal shielding layer 8, specifically, the inner side surface of the second insulating layer 3 may be provided with the metal shielding layer 8, the outer side surface of the second insulating layer 3 may be provided with the metal shielding layer 8, and the inside of the second insulating layer 3 may be provided with the metal shielding layer 8.

In some embodiments, the softening point temperature of the vacuum-impregnated resin film 412 is higher than the softening point temperature of the resin encapsulation layer 42. The vacuum-impregnated resin film 412 and the resin packaging layer 42 are both made of epoxy resin, and the vacuum-impregnated resin film 412 and the resin packaging layer 42 are different in specific components, so that the softening point temperature of the vacuum-impregnated resin film 412 is higher than that of the resin packaging layer 42 through different component ratios. In this way, when the resin encapsulation layer 42 is cast, the vacuum-impregnated resin film 412 can maintain higher hardness, and the vacuum-impregnated resin film 412 is prevented from being deformed to generate air gaps.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.