CN218918611U - Dry-type transformer with low-voltage foil-wound epoxy resin casting - Google Patents
Dry-type transformer with low-voltage foil-wound epoxy resin casting Download PDFInfo
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- CN218918611U CN218918611U CN202223173423.2U CN202223173423U CN218918611U CN 218918611 U CN218918611 U CN 218918611U CN 202223173423 U CN202223173423 U CN 202223173423U CN 218918611 U CN218918611 U CN 218918611U
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Abstract
The utility model discloses a processing technology of a low-voltage foil coil winding in a dry-type distribution transformer and the dry-type distribution transformer, which comprise a coil winding process and a coil integral casting forming process, wherein a low-voltage winding body is in spiral ring surrounding, the low-voltage winding body comprises a metal foil belt, an interlayer insulating layer positioned on one side surface of the metal foil belt and end insulating layers positioned at two ends of the metal foil belt, an inner insulating grid layer is arranged on the inner cavity surface of the low-voltage winding body, an outer insulating grid layer is arranged on the outer side wall surface of the low-voltage winding body, and the whole low-voltage winding body is covered on the inner insulating grid layer and the outer insulating grid layer by coating with epoxy resin casting layers. According to the utility model, the effect of increasing the adhesion stability of the surface epoxy resin casting layer by adding the insulating grid layer is optimized, the whole winding is fully sealed and integrally covered in an insulating manner, the insulating failure period is reduced, and the service life of the product is prolonged.
Description
Technical Field
The utility model relates to the technical field of dry-type distribution transformers, in particular to a dry-type transformer cast by low-voltage foil-wound epoxy resin.
Background
The dry-type transformer is a transformer which can go deep into a load center, can prevent fire and explosion and has excellent environmental protection performance, and along with the intensive residence and the increase of high-rise buildings and underground buildings, the urban power supply load is continuously increased, and the application of the dry-type transformer is also increasingly wide. The dry type transformer generally comprises a low-voltage coil, a high-voltage coil, an iron core, an insulating cylinder, an upper cushion block, a lower cushion block and the like, dust accumulation can occur on the surface of the transformer and the cushion block after the transformer is operated for a period of time, and particularly, the dust accumulation and the moisture are serious in a wet and salt mist environment. Under such environments, the low-voltage winding can be corroded for a long time, soluble substances in dirt on the insulating surface of the transformer are gradually dissolved in water, and a layer of conductive film is formed on the surface, so that the insulating level of the insulating layer is greatly reduced, and a severe discharge phenomenon, namely pollution flashover, is easy to generate under the action of a power field, so that the dry-type transformer is damaged.
Disclosure of Invention
Aiming at the problems, the utility model aims to provide a dry-type transformer which adopts low-voltage foil to wind epoxy resin casting, the effect of adding an insulating grid layer to increase the adhesion stability of a surface epoxy resin casting layer is optimized, the whole winding is fully sealed and integrally covered in an insulating manner, the insulation failure period is reduced, and the service life of a product is prolonged.
The technical problems solved by the utility model can be realized by adopting the following technical scheme:
the utility model provides an adopt low-voltage foil to wind dry-type transformer of epoxy pouring, includes the low-voltage winding body, the low-voltage winding body is the spiral ring and encircles, the low-voltage winding body includes the metal foil area, is located the interlayer insulating layer of metal foil area one side and the end insulating layer that is located the metal foil area both ends, low-voltage winding body inner chamber surface is equipped with inboard insulating grid layer, low-voltage winding body lateral wall surface is equipped with outside insulating grid layer, the low-voltage winding body is whole to have the epoxy pouring layer through the cladding, the epoxy pouring layer covers in inboard insulating grid layer and outside insulating grid layer.
The low-voltage winding is characterized by further comprising a plurality of heat dissipation air passages, wherein the heat dissipation air passages are positioned in the low-voltage winding body and are of an up-down through structure.
An air passage insulating grid layer is arranged on the side wall of the heat dissipation air passage, and an epoxy resin casting layer is covered on the outer surface of the air passage insulating grid layer.
The metal foil belt adopts a copper foil belt or an aluminum foil belt.
The interlayer insulating layer and the end insulating layer are made of DMD insulating paper.
The low-voltage winding device further comprises an inner metal row and an outer metal row, wherein the inner metal row is used for being welded and fixed with a metal foil strip at the inner starting end of the low-voltage winding body, and the outer metal row is used for being welded and fixed with a metal foil strip at the outermost tail end of the low-voltage winding body.
The heat dissipation air flue uses the two ends of the low-voltage winding body between the inner metal row and the outer metal row as the starting end and the tail end to be arranged at intervals.
The plurality of heat dissipation air passages are annularly arranged along the circumference, and the number of the annularly arranged heat dissipation air passages is at least 2 weeks.
The whole low-voltage winding body is of an oval structure.
The low-voltage winding body is surrounded by 4-8 layers of insulating layers, and the outer side of each insulating layer is surrounded and coated with the outer insulating grid layer.
Compared with the prior art, the utility model has the following beneficial effects: according to the utility model, the low-voltage winding structure is optimized, the insulation grid layer is additionally arranged to increase the adhesion stabilizing effect of the surface epoxy resin casting layer, and the epoxy resin integral coating structure is adopted to form the integral coverage of the fully-enclosed epoxy resin casting layer, so that the insulation failure period is reduced, and the service life of a product is prolonged.
The features of the present utility model will be apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of the overall structure of the present utility model;
FIG. 2 is a schematic view of a low voltage winding body of the present utility model in partial cross-section; wherein, 10, the low-voltage winding body; 11. a metal foil strip; 12. an interlayer insulating layer; 13. an end insulating layer; 20. a heat dissipation air passage; 30. an outer metal row; 40. an inner metal row; 50. an epoxy resin casting layer; 61. an outer insulating mesh layer; 62. an inner insulating mesh layer; 63. an air passage insulating grid layer.
Detailed Description
The utility model is further described with reference to the following detailed drawings in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the implementation of the utility model easy to understand.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear are used in the embodiments of the present utility model) are merely for explaining the relative positional relationship, movement conditions, and the like between the components in a certain specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicators are changed accordingly. Furthermore, the description of "first," "second," etc. in this disclosure is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature.
Example 1
Referring to fig. 1 to 2, this embodiment discloses a dry-type transformer cast by using low-voltage foil to wind epoxy resin, which comprises a low-voltage winding body 10, wherein the low-voltage winding body 10 is in a spiral ring surrounding to form an internal hollow structure, the whole low-voltage winding body 10 is in an elliptical structure, and the whole low-voltage winding body is in an arc surface, so that the winding size can be well controlled.
The low-voltage winding body 10 comprises a metal foil belt 11, an interlayer insulating layer 12 positioned on one side surface of the metal foil belt 11 and end insulating layers 13 positioned on two ends of the metal foil belt 11, wherein the metal foil belt 11 adopts a copper foil belt or an aluminum foil belt, the metal foil belt 11 is preferably annealed before being wound, internal stress is eliminated, cracking of an external coating layer caused by later deformation after winding is avoided, and particularly cracking of an epoxy resin casting layer 50 is avoided; the interlayer insulating layer 12 and the end insulating layer 13 are made of DMD insulating paper, 4-8 layers of insulating layers are wound on the outermost side of the low-voltage winding body 10, the outer side of the interlayer insulating layer 12 is wound on the outer insulating grid layer 61, the thickness of the insulating layer on the outer surface is increased, and the protection effect of the outer surface is improved.
Preferably, the inner cavity surface of the low-voltage winding body 10 is provided with an inner insulating grid layer 62, the outer side wall surface of the low-voltage winding body 10 is provided with an outer insulating grid layer 61, the inner insulating grid layer 62 and the outer insulating grid layer 61 are made of grid cloth with the thickness of 1.0 mm-1.5 mm, the whole low-voltage winding body 10 is covered with an epoxy resin casting layer 50 through being coated with the epoxy resin casting layer 50, the epoxy resin casting layer 50 is covered on the inner insulating grid layer 62 and the outer insulating grid layer 61, good adhesion can be formed by utilizing the inner insulating grid layer 62 and the outer insulating grid layer 61 of the grid structure, the whole coating effect of the epoxy resin casting layer 50 is better, the adhesion stability is improved, and the service life is prolonged.
Preferably, still include a plurality of heat dissipation air flue 20, heat dissipation air flue 20 is located low-voltage winding body 10, and heat dissipation air flue 20 is upper and lower through structure, before the epoxy pours, fills with the air flue board generally and keeps apart, then places 0.4mm ~0.5mm thick net cloth in the air flue board both sides, forms air flue insulating grid layer 63 for be equipped with air flue insulating grid layer 63 on the lateral wall of heat dissipation air flue 20, air flue insulating grid layer 63 surface covers has epoxy pouring layer 50, forms good adhesion effect.
In combination with the above, the low-voltage winding assembly further comprises an inner metal row 40 and an outer metal row 30, the inner metal row 40 is used for being welded and fixed with the metal foil tape 11 at the inner starting end of the low-voltage winding assembly 10, the outer metal row 30 is used for being welded and fixed with the metal foil tape 11 at the outermost end of the low-voltage winding assembly 10, the heat dissipation air passages 20 are distributed at intervals by taking the two ends of the low-voltage winding assembly 10 between the inner metal row 40 and the outer metal row 30 as the starting end, the plurality of heat dissipation air passages 20 are distributed annularly along the circumference, and the annular distribution quantity is at least 2 circumferences.
According to the utility model, the low-voltage winding structure is optimized, the insulation grid layer is additionally arranged to increase the adhesion stabilizing effect of the surface epoxy resin casting layer, and the epoxy resin integral coating structure is adopted to form the integral coverage of the fully-enclosed epoxy resin casting layer, so that the insulation failure period is reduced, and the service life of a product is prolonged.
Example 2
The embodiment 1 is combined, and the embodiment discloses a processing technology of a low-voltage foil-wound coil winding in a dry-type distribution transformer, which comprises the following steps of S1, a coil winding procedure, wherein equipment is a foil winding machine, a sub-arc welding machine, an air compressor and a crane; s1.1, knowing coil pattern patterns, defining the technical condition requirements, selecting a winding die with corresponding specification according to the inner diameter of a product to be processed, preparing required materials and used tools according to the patterns, checking whether the used equipment is normal or not, winding the wire after error is avoided, mounting the winding die on a foil winding machine, and uniformly coating a release agent on the outer surface of the winding die; s1.2, surrounding the outer surface of a winding former by at least one circle of insulating grid layer, surrounding the interlayer insulating layer by 2-5 circles along the winding former, fixing and bundling the metal foil strips welded with the inner end metal rows at the specified positions of the winding former by a fastening belt, and completing adjustment and tensioning to enable the metal foil strips to be in a tensioning state; s1.3, matching a corresponding end insulating layer and an interlayer insulating layer according to the thickness of the metal foil belt, wherein the interlayer insulating layer is positioned on the lower surface of the metal foil belt, and the end insulating layer is positioned at two ends of the metal foil belt to finish synchronous winding; the gap between the end insulating layer and the metal foil is kept to be 1.5 mm-2.0 mm; s1.4, continuously and synchronously winding a metal foil strip, an end insulating layer and an interlayer insulating layer, and placing an air passage stay according to the process requirement after the metal foil strip, the end insulating layer and the interlayer insulating layer are wound to the process requirement size; wherein, no airway stay is placed at the metal bus; the airway stay is placed for at least one week; the outer surface of the airway stay is provided with an insulating grid layer, and the number of the airway stay is preferably 2 weeks; s1.5, finishing the placement of the airway stay, continuously and synchronously winding the metal foil strip, the end insulating layer and the interlayer insulating layer, finishing the winding with the specified number of turns in the process, and finishing the shearing of the metal foil strip; when the last turn of metal foil tape is wound, the outer end metal row is welded and fixed with the metal foil tape at the end position through a welding machine; s1.6, continuously encircling the coil which is coiled by the interlayer insulating layer along the periphery for 2-5 circles, encircling the end insulating layer for one circle more than the interlayer insulating layer, reserving a thermometer plug-in port, and encircling an epoxy prepreg cloth on the outermost layer; s1.7, drying the coil subjected to the winding processing at the temperature of 140-160 ℃ for 150-210 min; s1.8, after cooling, demolding and separating the coil from the winding former, and polishing and trimming the size to form a coil semi-finished product.
S2, integrally casting and forming the coil: s2.1, placing the coil in an inner film, surrounding an insulating grid layer on the outer surface of the coil, closing the die, finishing die sealing glue filling at the joint, and aging for 60-120 min at room temperature after die sealing is finished; s2.2, after aging is finished, performing pre-drying treatment, wherein the pre-drying temperature is 100-120 ℃, the time is 600-900 min, and then cooling to 60-80 ℃ for more than 150 min; s2.3, carrying out internal vacuumizing treatment on a die for packaging the coil, wherein the vacuum degree is controlled to be 1-2 bar, the temperature is controlled to be 80-90 ℃, and the time is more than 120min; s2.4, completing the butt joint of the pouring pipe by the die for packaging the coil after the vacuumizing treatment, and completing the pouring; s2.5, cooling and solidifying, taking out the packaging mould after pouring, and passing through at least one solidifying period; s2.6, demoulding and trimming to obtain a finished product.
Further, the metal foil belt adopts a copper foil belt or an aluminum foil belt, and the metal bar adopts a copper bar.
Further, in step S2.4, the preparation of the castable is completed before casting, including: s2.41, respectively preheating the epoxy resin and the curing agent at the temperature of 60-70 ℃ for 660-750 min; s2.42, respectively placing the epoxy resin and the curing agent which are preheated in respective preheating tanks, continuously preheating, wherein the preheating temperature is 60-70 ℃, vacuumizing, controlling the vacuum degree to be 0.5-1 mbar, and keeping the vacuum degree for 120-240 min; s2.42, keeping the temperature in the final mixing tank at 60-70 ℃, controlling the vacuum degree at 1-2 mbar, and feeding the epoxy resin and the curing agent in the respective pre-heating tanks into the final mixing tank.
Further, in step S2.4, the pouring rate is such that the pouring amount of a single pouring tube should not exceed 1kg per stroke and the maximum flow rate should not exceed 50kg/h per pouring head.
Further, in step S2.4, after the casting is completed, the vacuum pumping time is kept for 10 to 30 minutes.
The casting material is mainly epoxy resin and curing agent, and the auxiliary material is mold release agent, polyethyl acetate, gypsum powder, xylene, alcohol and other materials, wherein in the casting proportion, 100 parts of epoxy resin is matched with 80 parts of curing agent.
In the above, the molding compound is prepared by mixing gypsum powder with appropriate amount of polyvinyl acetal, and mixing with polyvinyl acetate to obtain a viscous state, wherein the weight of the molding compound is usually 100 parts of gypsum powder, 40 parts of polyvinyl acetal and 15 parts of polyvinyl acetate.
| Project | Tensile Strength | Flexural Strength | Weak base influence | Weak acid influence | Influence of strong acids | Environmental grade | Withstand voltage to ground power frequency |
| Low-voltage common foil winding | 195Mpa | 200Mpa | Erosion of | Erosion of | Erosion of | E1 level | 7kV |
| Low-voltage foil-wound epoxy resin casting winding | 290Mpa | 350Mpa | Slightly affect | Without any means for | Small size | E2 stage | 10kV |
The utility model optimizes the winding process and is convenient for combining with the follow-up completion of epoxy resin casting molding; the processing technology of the low-voltage winding is optimized, the insulating grid layer is additionally arranged to increase the adhesion stabilizing effect of the surface epoxy resin casting layer, and the epoxy resin casting is carried out in a vacuum environment, so that the whole coverage of the fully-closed epoxy resin casting layer is formed, the insulation failure period is reduced, and the service life of a product is prolonged.
The foregoing description is only a preferred embodiment of the present utility model, and is not intended to limit the utility model in any way, but any simple modification, equivalent variation or modification made to the above embodiments according to the technical principles of the present utility model still falls within the scope of the technical solutions of the present utility model.
Claims (10)
1. A low voltage foil-wound epoxy resin cast dry transformer, characterized by: including the low-voltage winding body, the low-voltage winding body is the spiral ring and encircles, the low-voltage winding body includes the metal foil area, is located the interlayer insulating layer of a metal foil area side and the end insulating layer that is located metal foil area both ends, low-voltage winding body inner chamber surface is equipped with inboard insulating grid layer, low-voltage winding body lateral wall surface is equipped with outside insulating grid layer, the low-voltage winding body is whole to have epoxy pouring layer through the cladding, epoxy pouring layer covers in inboard insulating grid layer and outside insulating grid layer.
2. A low voltage foil-wound epoxy resin molded dry transformer as claimed in claim 1, wherein: the low-voltage winding is characterized by further comprising a plurality of heat dissipation air passages, wherein the heat dissipation air passages are positioned in the low-voltage winding body and are of an up-down through structure.
3. A low voltage foil-wound epoxy resin molded dry transformer as claimed in claim 2, wherein: an air passage insulating grid layer is arranged on the side wall of the heat dissipation air passage, and an epoxy resin casting layer is covered on the outer surface of the air passage insulating grid layer.
4. A low voltage foil-wound epoxy resin molded dry transformer as claimed in claim 1, wherein: the metal foil belt adopts a copper foil belt or an aluminum foil belt.
5. A low voltage foil-wound epoxy resin molded dry transformer as claimed in claim 1, wherein: the interlayer insulating layer and the end insulating layer are made of DMD insulating paper.
6. A low voltage foil-wound epoxy resin molded dry transformer as claimed in any one of claims 1 to 5, wherein: the low-voltage winding device further comprises an inner metal row and an outer metal row, wherein the inner metal row is used for being welded and fixed with a metal foil strip at the inner starting end of the low-voltage winding body, and the outer metal row is used for being welded and fixed with a metal foil strip at the outermost tail end of the low-voltage winding body.
7. A low voltage foil-wound epoxy resin molded dry transformer in accordance with claim 6, wherein: the heat dissipation air flue uses the two ends of the low-voltage winding body between the inner metal row and the outer metal row as the starting end and the tail end to be arranged at intervals.
8. A low voltage foil-wound epoxy resin molded dry transformer in accordance with claim 6, wherein: the plurality of heat dissipation air passages are annularly arranged along the circumference, and the number of the annularly arranged heat dissipation air passages is at least 2 weeks.
9. A low voltage foil-wound epoxy resin molded dry transformer in accordance with claim 8, wherein: the whole low-voltage winding body is of an oval structure.
10. A low voltage foil-wound epoxy resin molded dry transformer as claimed in claim 9, wherein: the low-voltage winding body is surrounded by 4-8 layers of insulating layers, and the outer side of each insulating layer is surrounded and coated with the outer insulating grid layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223173423.2U CN218918611U (en) | 2022-11-29 | 2022-11-29 | Dry-type transformer with low-voltage foil-wound epoxy resin casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223173423.2U CN218918611U (en) | 2022-11-29 | 2022-11-29 | Dry-type transformer with low-voltage foil-wound epoxy resin casting |
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| Publication Number | Publication Date |
|---|---|
| CN218918611U true CN218918611U (en) | 2023-04-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223173423.2U Active CN218918611U (en) | 2022-11-29 | 2022-11-29 | Dry-type transformer with low-voltage foil-wound epoxy resin casting |
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| Country | Link |
|---|---|
| CN (1) | CN218918611U (en) |
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- 2022-11-29 CN CN202223173423.2U patent/CN218918611U/en active Active
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