CN113963917A - Structure and method for effectively reducing partial discharge of dry-type transformer - Google Patents
Structure and method for effectively reducing partial discharge of dry-type transformer Download PDFInfo
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- CN113963917A CN113963917A CN202111178231.8A CN202111178231A CN113963917A CN 113963917 A CN113963917 A CN 113963917A CN 202111178231 A CN202111178231 A CN 202111178231A CN 113963917 A CN113963917 A CN 113963917A
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- epoxy glass
- grid cloth
- wires
- cloth
- glass grid
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/32—Insulating of coils, windings, or parts thereof
- H01F27/323—Insulation between winding turns, between winding layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/32—Insulating of coils, windings, or parts thereof
- H01F27/324—Insulation between coil and core, between different winding sections, around the coil; Other insulation structures
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/32—Insulating of coils, windings, or parts thereof
- H01F27/327—Encapsulating or impregnating
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
- H01F41/12—Insulating of windings
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Insulating Of Coils (AREA)
Abstract
The invention discloses a structure and a method for effectively reducing partial discharge of a dry-type transformer, and relates to the technical field of transformers. The high-voltage coil is wound with a plurality of layers of inner epoxy glass grid cloth, a plurality of layers of wires are wound on the inner epoxy glass grid cloth, a layer of interlayer epoxy glass grid cloth is arranged between adjacent upper and lower layers of wires in a spacing mode and serves as an electrical isolation layer and an insulation layer, DMD insulation is arranged between the upper and lower layers of wires when the upper and lower layers of wires rise, an outer epoxy glass grid cloth is wound on the outermost layer of wires, epoxy resin is filled between the wires and the inner epoxy glass grid cloth, between the interlayer epoxy glass grid cloth and the outer epoxy glass grid cloth in a pouring mode, and the epoxy glass grid cloth is embedded into the epoxy resin in a criss-cross mode and is fused with the epoxy resin into a whole. The method is simple to implement, has obvious effect, can effectively permeate the epoxy resin in a vacuum environment, improves the insulativity of a product, reduces the local discharge capacity, effectively eliminates hidden dangers, and has low manufacturing cost, economy, reliability and wide application prospect.
Description
Technical Field
The invention relates to the technical field of transformers, in particular to a structure and a method for effectively reducing partial discharge of a dry-type transformer.
Background
The dry type transformer is different from an oil immersed transformer, mainly adopts solid insulation, and increases the detection of partial discharge capacity as an important assessment index of product safety. The insulation medium of the dry-type transformer generally adopts epoxy resin, so the quality and effective permeation filling of the epoxy resin directly influence the insulation and partial discharge level of the product, and the actual insulation result of the epoxy resin is greatly different due to the influence of factors such as the proportion of the added components, the coil structure, the pouring and curing process and the like.
At present, although manufacturers adopt a vacuum casting process for effective permeation of epoxy resin, coils generally adopt a DMD insulation method as an interlayer insulation material, the DMD has good electrical performance, but the surface is relatively flat and is combined with a wire forming surface, and epoxy resin is difficult to permeate effectively, so that air holes and microscopic defects of turn-to-turn wires, the DMD and the wire insulation cannot be filled effectively in an insulation manner, high local field intensity can be generated in the areas, and irreversible damage to a dielectric medium is generated until final breakdown along with formation and extension of branch-shaped channels (local discharge and electric trees), so that the safe use of products is affected.
In order to solve the above problems, it is particularly necessary to design a novel structure and method for effectively reducing the partial discharge of the dry-type transformer.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the structure and the method for effectively reducing the partial discharge of the dry-type transformer, which have the advantages of simple structure, reasonable design, effective permeation of epoxy resin in a vacuum environment, improvement of the insulativity of a product, reduction of the partial discharge amount, easiness in implementation, low manufacturing cost, remarkable practical effect and easiness in popularization and use.
In order to achieve the purpose, the invention is realized by the following technical scheme: a structure for effectively reducing partial discharge of a dry-type transformer comprises a high-voltage coil, inner epoxy glass grid cloth, wires, interlayer epoxy glass grid cloth, outer epoxy glass grid cloth and epoxy resin, wherein multiple layers of inner epoxy glass grid cloth are wound on the high-voltage coil, multiple layers of wires are wound on the inner epoxy glass grid cloth, a layer of interlayer epoxy glass grid cloth is arranged between adjacent upper and lower layers of wires in a spaced mode and serves as an electrical isolation and insulation layer, the upper and lower layers of wires are insulated in a spaced mode through DMD pads, the outermost layer of wire is wound with outer epoxy glass grid cloth, epoxy resin is filled among the wires, the inner epoxy glass grid cloth, the interlayer epoxy glass grid cloth and the outer epoxy glass grid cloth in a pouring mode, and the epoxy glass grid cloth is embedded into the epoxy resin in a criss-cross mode and is fused with the epoxy resin into a whole.
Preferably, the inner epoxy glass mesh cloth is provided with 2-4 layers.
Preferably, the thickness of the inner epoxy glass mesh cloth is 1.2mm, and the width of the inner epoxy glass mesh cloth is selected according to the total axial height of the high-voltage coil, so that the two axial ends of the high-voltage coil are not exposed.
Preferably, the thickness of the interlayer epoxy glass gridding cloth is 0.4mm, the width of the interlayer epoxy glass gridding cloth is 10mm wider than a line segment formed by the conducting wires, and the interlayer epoxy glass gridding cloth is placed evenly on the left and the right.
Preferably, the interlayer epoxy glass gridding cloth 4 is uniformly padded between the upper layer of conducting wire 3 and the lower layer of conducting wire 3, and the head and the tail of the conducting wire are lapped by about 30 mm.
Preferably, the conducting wire 3 is additionally provided with a DMD insulating pad interval of 0.2mm during the layer rising.
Preferably, the outer epoxy glass mesh cloth is provided with 1-3 layers.
Preferably, the thickness of the outer epoxy glass mesh cloth is 1.2mm, and the width of the outer epoxy glass mesh cloth is selected according to the total axial height of the high-voltage coil, so that the two axial ends of the high-voltage coil are not exposed.
Preferably, the wire is made of copper or aluminum, and is one of an enameled or composite film insulated wire.
A method for effectively reducing partial discharge of a dry-type transformer comprises the following steps: firstly, winding 2-4 layers of inner epoxy glass gridding cloth with the thickness of 1.2mm on a coil mould, winding a lead on the inner epoxy glass gridding cloth, uniformly spacing an interlayer epoxy glass gridding cloth with the thickness of 0.4mm between an upper layer lead and a lower layer lead, wherein the width of the interlayer epoxy glass gridding cloth is 10mm wider than the line section formed by the lead, and the interlayer epoxy glass gridding cloth is uniformly placed left and right; DMD insulation is padded between the upper layer of conducting wires and the lower layer of conducting wires when the conducting wires rise, and then 1-3 layers of outer epoxy glass mesh cloth with the thickness of 1.2mm are wound outside the outermost layer of the conducting wires; and finally, sleeving an outer mold and the inner mold outside the high-voltage coil, drying, then performing vacuum epoxy resin pouring and filling in a vacuum pouring tank, and performing step temperature control curing and forming.
The invention has the beneficial effects that: the device is simple to implement, low in manufacturing cost, economical and reliable, can enable the main insulating medium epoxy resin to effectively permeate in a vacuum environment, improves the insulating reliability of products, reduces the local discharge capacity, effectively avoids hidden dangers, and is remarkable in actual effect and wide in application prospect.
Drawings
The invention is described in detail below with reference to the drawings and the detailed description;
FIG. 1 is a schematic structural view of an embodiment of the present invention;
fig. 2 is an enlarged schematic view of a portion a in fig. 1.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
Referring to fig. 1-2, the following technical solutions are adopted in the present embodiment: a structure for effectively reducing partial discharge of a dry-type transformer comprises a high-voltage coil 1, an inner epoxy glass mesh cloth 2, a lead 3, an interlayer epoxy glass mesh cloth 4, an outer epoxy glass mesh cloth 5 and epoxy resin 6, wherein the high-voltage coil is of a segmented double-layer or multi-layer structure, the high-voltage coil 1 is wound with a plurality of layers of inner epoxy glass gridding cloth 2, a plurality of layers of wires 3 are wound on the inner epoxy glass gridding cloth 2, a layer of interlayer epoxy glass gridding cloth 4 is arranged between adjacent upper and lower layers of wires 3 in a spacing way, DMD insulation is arranged between the upper and lower layers of wires 3 in a spacing way, an outer epoxy glass gridding cloth 5 is wound on the outermost layer of wires 3, epoxy resin 6 is filled between the wires 3 and the inner epoxy glass gridding cloth 2, between the interlayer epoxy glass gridding cloth 4 and the outer epoxy glass gridding cloth 5 in a pouring way, and the epoxy glass gridding cloth is embedded in the epoxy resin 6 in a criss-cross mode and is fused with the epoxy resin 6 into a whole.
It is worth noting that each epoxy glass mesh cloth is formed by interweaving alkali-free glass fiber yarns and polyester yarns into mesh gray cloth with square holes, dehydrating at high temperature, soaking with epoxy resin glue, drying, curing and shaping, the thickness is 0.4-1.2mm, and the width is determined according to the height of a coil section and the whole axial height.
In addition, the lead 3 is made of copper or aluminum, and is an enameled or composite film insulated lead.
The high-voltage coil 1 of the specific embodiment adopts a segmented cylinder layer type structure, firstly, an inner epoxy glass gridding cloth 2 is wound on a special coil mould, the inner epoxy glass gridding cloth 2 is provided with 2-4 layers, the thickness of the inner epoxy glass gridding cloth is 1.2mm, the width is selected according to the total axial height of the high-voltage coil 1, and the two axial ends of the high-voltage coil 1 are not exposed; winding the wires 3 on the inner epoxy glass grid cloth 2, uniformly padding an interlayer epoxy glass grid cloth 4 between the upper layer of wires and the lower layer of wires, connecting the wires end to end by about 30mm, wherein the thickness of the interlayer epoxy glass grid cloth 4 is 0.4mm, the width of the interlayer epoxy glass grid cloth 4 is 10mm wider than the line segment formed by the wires 3, and the wires are uniformly placed left and right; DMD insulation with 0.2mm interval is padded between the upper layer of lead 3 and the lower layer of lead when the layer rises, then outer epoxy glass mesh cloth 5 is wound outside the outermost layer of the lead 3, the thickness of the outer epoxy glass mesh cloth 5 is 1.2mm, the width is selected according to the total axial height of the high-voltage coil 1, and the two axial ends of the high-voltage coil 1 are ensured not to be exposed; and finally, sleeving an outer mold and the inner mold outside the high-voltage coil 1, drying, pouring and filling the vacuum epoxy resin 6 in a special vacuum pouring tank, and performing stepped temperature control curing molding according to an epoxy resin curing temperature curve.
The whole body of the embodiment adopts vacuum degassing, material mixing, pouring and ladder temperature control curing molding, the inner epoxy glass gridding cloth is placed before the inner part of the coil is wound, the interlayer epoxy glass gridding cloth is placed between the conductor layer and the layer to be used as an electrical isolation and insulation layer, DMD (digital micromirror device) reinforcement insulation is padded when the conductor rises the layer, the outer epoxy glass gridding cloth is placed outside the coil, the conductor and the epoxy glass gridding cloth are subjected to epoxy resin vacuum pouring in a special vacuum tank through a special mold, and the conductor and the epoxy glass gridding cloth are cured into a whole body through a curing furnace. The used epoxy glass gridding cloth shows local fluctuation, is flat and provided with square holes integrally, and epoxy resin can effectively permeate into the high-voltage coil from various angles to effectively electrically isolate the lead so as to avoid partial discharge caused by microscopic defects; and because the epoxy glass mesh cloth has higher strength, is embedded in the epoxy resin in a criss-cross manner and is integrated with the epoxy resin, the cracking can be avoided, the short-circuit electrodynamic force impact capacity of the coil is improved, and the reliable operation of the product is ensured. The specific technical advantages are as follows:
(1) the epoxy glass grid cloth is thoroughly impregnated by epoxy resin, has no bubbles inside, no partial discharge and high insulation level, can be effectively fused with coil epoxy resin, and effectively avoids additional partial discharge interference on products;
(2) the glass fiber yarns and the polyester yarns of the epoxy glass grid cloth are transversely and longitudinally interlaced, are in a corrugated high-low state locally, are flat and tough as a whole, can allow epoxy resin to effectively flow and permeate through holes, can avoid uneven conductor placement, effectively solves the problem that epoxy resin possibly permeates to generate pores due to incapability of permeating, and reduces partial discharge;
(3) the epoxy resin has a large expansion coefficient, and has the hidden danger of expansion cracking after being heated, and the epoxy glass mesh cloth has high mechanical strength and is embedded in the epoxy resin and the conducting wire, so that the coil cracking caused by the cold and hot effects of the coil and the electrodynamic force when the coil is suddenly short-circuited can be effectively prevented, and the mechanical strength of the coil is improved;
(4) the coil layers are in a grid shape, the condition of the covered next layer of wires can be seen in real time, the upper and lower alignment is facilitated, the existing insulation damage and other problems can be found in time, hidden dangers are eliminated, the implementation is simple, economic and reliable, and the wire winding device has a wide market application prospect.
The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. A structure for effectively reducing partial discharge of a dry-type transformer is characterized by comprising a high-voltage coil (1), an inner epoxy glass grid cloth (2), wires (3), an interlayer epoxy glass grid cloth (4), an outer epoxy glass grid cloth (5) and epoxy resin (6), wherein the high-voltage coil (1) is wound with a plurality of layers of inner epoxy glass grid cloth (2), the inner epoxy glass grid cloth (2) is wound with a plurality of layers of wires (3), a layer of interlayer epoxy glass grid cloth (4) is arranged between adjacent upper and lower layers of wires (3), DMD insulation is arranged between the upper and lower layers of wires (3) when the upper and lower layers of wires rise, the outermost layer of wires (3) is wound with the outer epoxy glass grid cloth (5), and the epoxy resin (6) is filled between the wires (3) and the inner epoxy glass grid cloth (2), the interlayer epoxy glass grid cloth (4) and the outer epoxy glass grid cloth (5), the epoxy glass gridding cloth is embedded in the epoxy resin (6) in a criss-cross manner and is integrated with the epoxy resin (6).
2. The structure for effectively reducing partial discharge of the dry type transformer according to claim 1, wherein the inner epoxy glass mesh cloth (2) is provided with 2-4 layers; the thickness of the inner epoxy glass gridding cloth (2) is 1.2 mm.
3. The structure for effectively reducing partial discharge of the dry type transformer according to claim 1, wherein the thickness of the interlayer epoxy glass mesh cloth (4) is 0.4 mm.
4. The structure for effectively reducing partial discharge of the dry-type transformer according to claim 1, wherein the width of the interlayer epoxy glass mesh cloth (4) is 10mm wider than the line segment formed by the conducting wires (3) and is uniformly arranged.
5. The structure for effectively reducing the partial discharge of the dry-type transformer according to claim 1, wherein the interlayer epoxy glass mesh cloth (4) is uniformly spaced between the upper layer of conducting wire (3) and the lower layer of conducting wire (3) and is lapped end to end for about 30 mm.
6. The structure for effectively reducing partial discharge of dry type transformer according to claim 1, wherein said conducting wires (3) are added with 0.2mm DMD insulating pad during layer-lifting.
7. The structure for effectively reducing partial discharge of the dry type transformer according to claim 1, wherein the outer epoxy glass mesh fabric (5) is provided with 1-3 layers.
8. The structure for effectively reducing partial discharge of dry type transformer according to claim 1, wherein the thickness of said outer epoxy glass mesh cloth (5) is 1.2 mm.
9. The structure for effectively reducing partial discharge of the dry-type transformer according to claim 1, wherein the conducting wire (3) is made of one of copper or aluminum, enameled or composite film insulated conducting wire.
10. A method for effectively reducing partial discharge of a dry-type transformer is characterized by comprising the following steps: firstly, winding 2-4 layers of inner epoxy glass grid cloth (2) with the thickness of 1.2mm on a coil mould, winding a lead (3) on the inner epoxy glass grid cloth (2), uniformly padding an interlayer epoxy glass grid cloth (4) with the thickness of 0.4mm between an upper layer lead and a lower layer lead (3), wherein the width of the interlayer epoxy glass grid cloth (4) is 10mm wider than the line segment formed by the leads (3), and the interlayer epoxy glass grid cloth and the lead are uniformly placed left and right; DMD insulation is padded between the upper layer of conducting wires and the lower layer of conducting wires (3) when the conducting wires rise, and then 1-3 layers of outer epoxy glass mesh cloth (5) with the thickness of 1.2mm are wound outside the outermost layer of the conducting wires (3); and finally, sleeving an outer mold and the inner mold outside the high-voltage coil (1), drying, pouring and filling the vacuum epoxy resin (6) in a vacuum pouring tank, and performing stepped temperature control curing molding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111178231.8A CN113963917A (en) | 2021-10-09 | 2021-10-09 | Structure and method for effectively reducing partial discharge of dry-type transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111178231.8A CN113963917A (en) | 2021-10-09 | 2021-10-09 | Structure and method for effectively reducing partial discharge of dry-type transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113963917A true CN113963917A (en) | 2022-01-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111178231.8A Withdrawn CN113963917A (en) | 2021-10-09 | 2021-10-09 | Structure and method for effectively reducing partial discharge of dry-type transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113963917A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114530323A (en) * | 2022-03-03 | 2022-05-24 | 江苏华辰变压器股份有限公司 | Coil winding process of 35 kV-level and below epoxy-cast dry-type transformer |
-
2021
- 2021-10-09 CN CN202111178231.8A patent/CN113963917A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114530323A (en) * | 2022-03-03 | 2022-05-24 | 江苏华辰变压器股份有限公司 | Coil winding process of 35 kV-level and below epoxy-cast dry-type transformer |
| CN114530323B (en) * | 2022-03-03 | 2023-08-08 | 江苏华辰变压器股份有限公司 | Winding process of epoxy casting dry-type transformer coil with voltage of 35kV level and below |
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Application publication date: 20220121 |
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| WW01 | Invention patent application withdrawn after publication |