Insulation structure of foil-wound cast coil lead bar
By wrapping the lead strip of the dry transformer foil around the cast coil, the glass wire mat, and filling the glass wire mesh cloth, the problem of lead strip cracking under the C3 and C4 climate levels is solved, and higher mechanical strength and insulation performance are achieved to ensure the stable operation of the equipment under harsh conditions.
Patent Information
- Application Number
- CN202421419537.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-20
- Publication Date
- 2025-03-28
- Estimated Expiration
- 2034-06-20
AI Technical Summary
The foil-winding cast coils of existing dry transformers are prone to cracking at the lead-line roots under the C3 and C4 climate levels, especially in temperatures ranging from -40℃ to -50℃.
The inner lead row 4 and outer lead row 5 respectively wrap the prepreg shrink belt and the glass wire mat, and fill the insulating layer with glass wire mesh cloth, forming an insulating protective structure to enhance mechanical strength and insulation performance.
It effectively prevents the leads from breaking or deforming due to concentrated stress at the bend, improves mechanical strength and insulation performance, and ensures safe, reliable and stable operation under harsh climate conditions.
Smart Images
Figure CN222690500U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of dry-type transformers, in particular to an insulation structure of a foil-wound cast coil lead row. Background Art
[0002] As is known to all, the IEC 60076-11 and GB / T 1094.11 standards clearly stipulate the operating conditions of transformers under various climate levels, and clearly explain the standard requirements for the climate performance level of dry-type transformers, which means that the market for dry-type cast transformers is moving towards requiring them to be able to be stored and operated under increasingly harsh climate conditions. At present, dry-type transformers with C2 climate level performance can no longer meet the needs of domestic and foreign markets. More and more foreign markets, such as the Russian market, require dry-type transformers to reach C3 and C4 climate level products.
[0003] As we all know, for epoxy resin cast dry-type transformers, the most prone to cracking problems are the cast coils during operation and storage under various climate levels. For foil-wound cast coils, the most prone to cracking under C3 and C4 climate levels is the root of the lead row. In the -40℃ to -50℃ thermal shock test, a strong traction force is generated in the root area of the lead row of the foil-wound cast coil. These stresses are too concentrated and are more prone to cracking. How to ensure that the root area of the lead row of the foil-wound cast coil of the dry-type transformer does not crack when it is stored and powered on under the standard requirements of the C3 and C4 climate levels is a difficult problem that the dry-type transformer industry urgently needs to solve.
[0004] In the prior art, the foil-wound cast coil of the dry-type transformer is stored and operated in a C2 climate level, i.e., a temperature environment of -25°C and below. The treatment of the lead bank of the foil-wound cast coil is mainly to lay 3 to 4 layers of insulating paper on the upper and lower sides of the lead bank after the lead bank is welded. The width of the insulating paper is twice the width of the lead bank. The lead bank is half-wrapped with 0.2×30mm insulating paper at the root of the lead bank. The wrapping height is 5 to 10mm below the second bending position. No special treatment is done to the positions on both sides of the lead bank and the lead bank itself.
[0005] The above-mentioned treatment method of the lead row of the foil-wound cast coil can only meet the storage and operation of the dry-type cast transformer in a -25°C climate level environment, but for a -40 to -50°C climate level, this insulation filling method has a great risk of cracking. Summary of the invention
[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the utility model is to provide a foil-wound cast coil lead row insulation structure, by wrapping the inner lead row 4 and the outer lead row 5 with a prepreg shrink tape 7, a first glass fiber felt 8 and a second glass fiber felt 9 respectively, and filling the outer insulation layer 3 and the outer lead row 5, and the inner insulation layer 2 and the inner lead row 4 with a first glass fiber mesh cloth 10 and a second glass fiber mesh cloth 11 respectively, thereby providing insulation protection for the foil cast coil 1, so that the foil-wound cast coil 1 of the dry-type transformer can operate safely, reliably and stably in a climate level environment of -40 to -50°C; the structure is simple, the crack resistance is extremely high, the stability is strong, the adaptability is wide, the environmental protection and energy saving and the economic benefits are remarkable.
[0007] In order to achieve the above purpose, the technical solution adopted by the utility model is:
[0008] A foil-wound cast coil lead row insulation structure, comprising a foil cast coil 1, wherein the inner surface and the outer surface of the foil cast coil 1 are respectively provided with an inner insulation layer 2 and an outer insulation layer 3, and the foil material of the foil cast coil 1 is respectively provided with an inner lead row 4 and an outer lead row 5, wherein the positions between the second bend 6 of the inner lead row 4 and the outer lead row 5 and the upper end of the foil cast coil 1 are both wrapped with a prepreg shrink tape 7, and the positions of the inner lead row 4 and the outer lead row 5 at the same height as the foil cast coil 1 are respectively wrapped with a first glass fiber felt 8 and a second glass fiber felt 9;
[0009] The second glass fiber felt 9 is wrapped with an outer insulating layer 3 , and a first glass fiber mesh cloth 10 is filled between the outer insulating layer 3 and the outer lead row 5 ; a second glass fiber mesh cloth 11 is filled between the inner insulating layer 2 and the inner lead row 4 .
[0010] The outer portion of the outer insulating layer 3 is further wrapped with a third glass fiber mesh cloth 12 .
[0011] The prepreg shrink tape 7 is wrapped in two layers by half overlap, and the wrapping position is between 5 to 10 mm below the second bend 6 and flush with the upper end of the foil casting coil 1.
[0012] The heights of the first glass fiber mat 8 and the second glass fiber mat 9 are the same as that of the foil cast coil 1 , and the widths thereof are three times the widths of the inner lead row 4 and the outer lead row 5 , respectively.
[0013] The first glass fiber mesh cloth 10 and the second glass fiber mesh cloth 11 are both filled in a step-by-step manner, and the filling positions are 150 mm below the upper end of the foil casting coil 1 and 150 mm above the lower end.
[0014] The outer insulating layer 3 is a polyester tape or a non-woven tape with a thickness of 0.2 to 0.3 mm and a width of 30 to 50 mm.
[0015] The prepreg shrink tape 7 has a thickness of 0.2-0.4 mm and a width of 30-40 mm.
[0016] Compared with the prior art, the utility model has the following beneficial effects:
[0017] 1. The utility model wraps a prepreg shrink tape 7 between the second bend 6 of the inner lead row 4 and the outer lead row 5 and 5, 5 to the position where the second bend 6 is 5 to 10 mm downward and the upper end of the foil cast coil 1 is flush, thereby providing additional support and reinforcement, effectively preventing the lead from breaking or deforming due to stress concentration at the bend, and improving the mechanical strength.
[0018] 2. The utility model wraps the first glass fiber felt 8 and the second glass fiber felt 9 at the same height as the inner lead row 4 and the outer lead row 5 and the foil cast coil 1, thereby significantly improving the insulation performance of the entire system and ensuring the safe operation of the electrical equipment; at the same time, the first glass fiber felt 8 and the second glass fiber felt 9 have certain mechanical strength and toughness after resin casting, which can reduce the external force impact on the inner lead row 4 and the outer lead row 5, and can effectively prevent deformation or cracking caused by external impact, thereby extending their service life.
[0019] 3. The utility model can further improve the insulation performance of the combination of the inner lead row 4 and the outer lead row 5 with the inner insulation layer 2 and the outer insulation layer 3 by filling the first glass fiber mesh cloth 10 between the outer insulation layer 3 and the outer lead row 5, and filling the second glass fiber mesh cloth 11 between the inner insulation layer 2 and the inner lead row 4; at the same time, the first glass fiber mesh cloth 10 and the second glass fiber mesh cloth 11 have good flexibility and high tensile strength, and can effectively prevent cracking caused by external impact.
[0020] 4. The first glass fiber mesh cloth 10 and the second glass fiber mesh cloth 11 of the utility model adopt step-by-step filling to improve the mechanical strength of the end of the foil cast coil 1, significantly improve the anti-cracking strength of the end of the foil cast coil 1, and extend its service life.
[0021] To sum up, the utility model has a simple structure, high crack resistance, strong stability, wide adaptability, environmental protection and energy saving, and significant economic benefits. It can operate safely, reliably and stably in a climate environment of -40 to -50°C, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a partial cross-sectional view of the insulation structure of the foil-wound cast coil lead row of the utility model.
[0023] Figure 2 It is a front view of the insulation structure of the foil-wound cast coil lead row of the utility model.
[0024] Figure 3It is a top view of the insulation structure of the foil-wound cast coil lead row of the utility model.
[0025] Among them: 1-foil cast coil; 2-inner insulation layer; 3-outer insulation layer; 4-inner lead row; 5-outer lead row; 6-second bend; 7-prepreg shrink tape; 8-first glass fiber felt; 9-second glass fiber felt; 10-first glass fiber mesh cloth; 11-second glass fiber mesh cloth; 12-third glass fiber mesh cloth. DETAILED DESCRIPTION
[0026] The utility model is further described in detail below in conjunction with the accompanying drawings.
[0027] See also Figure 1 , Figure 2 and Figure 3 A foil-wound cast coil lead row insulation structure, comprising a foil cast coil 1, wherein the inner surface and the outer surface of the foil cast coil 1 are respectively provided with an inner insulating layer 2 and an outer insulating layer 3, and the foil material of the foil cast coil 1 is respectively provided with an inner lead row 4 and an outer lead row 5, wherein the positions between the second bend 6 of the inner lead row 4 and the outer lead row 5 and the upper end of the foil cast coil 1 are both wrapped with a prepreg shrink tape 7, and the positions of the inner lead row 4 and the outer lead row 5 at the same height as the foil cast coil 1 are respectively wrapped with a first glass fiber felt 8 and a second glass fiber felt 9;
[0028] The second glass fiber felt 9 is wrapped with an outer insulating layer 3 , and a first glass fiber mesh cloth 10 is filled between the outer insulating layer 3 and the outer lead row 5 ; a second glass fiber mesh cloth 11 is filled between the inner insulating layer 2 and the inner lead row 4 .
[0029] This embodiment can further improve the insulation performance of the combination of the inner lead row 4 and the outer lead row 5 with the inner insulation layer 2 and the outer insulation layer 3 by filling the first glass fiber mesh cloth 10 between the outer insulation layer 3 and the outer lead row 5, and filling the second glass fiber mesh cloth 11 between the inner insulation layer 2 and the inner lead row 4; at the same time, the first glass fiber mesh cloth 10 and the second glass fiber mesh cloth 11 have good flexibility and high tensile strength, and can effectively prevent cracking caused by external impact.
[0030] like Figure 1 As shown, the outer side of the outer insulating layer 3 is also wrapped with a third glass fiber mesh cloth 12 to further improve the insulation strength and mechanical properties of the outer surface of the foil-wound cast coil.
[0031] like Figure 1 and Figure 2 As shown, the prepreg shrink tape 7 is wrapped in two layers of half overlap, and the wrapping position is between 5 to 10 mm below the second bend 6 and flush with the upper end of the foil cast coil 1, which improves the appearance quality of the foil cast coil and also improves the insulation strength and mechanical properties.
[0032] like Figure 1 As shown, the heights of the first glass felt 8 and the second glass felt 9 are the same as the height of the foil cast coil 1, and the widths are 3 times the widths of the inner lead row 4 and the outer lead row 5. The first glass felt 8 and the second glass felt 9 significantly improve the insulation performance of the entire system, ensuring the safe operation of the electrical equipment; at the same time, the first glass felt 8 and the second glass felt 9 have certain strength and toughness, which can reduce the external force impact on the inner lead row 4 and the outer lead row 5, and can effectively prevent deformation or cracking caused by external impact, thereby extending their service life.
[0033] like Figure 3 As shown, the first glass fiber mesh cloth 10 and the second glass fiber mesh cloth 11 are both filled in a step-by-step manner, and the filling position is 150 mm below the upper end of the foil cast coil 1 and 150 mm above the lower end. The outer insulating layer 3 is a polyester tape or a non-weft tape with a thickness of 0.2 to 0.3 mm and a width of 30 to 50 mm. The first glass fiber mesh cloth 10 and the second glass fiber mesh cloth 11 are filled in a step-by-step manner, which significantly improves the mechanical strength and crack resistance of the end of the foil cast coil 1 and prolongs its service life.
[0034] The prepreg shrink tape 7 has a thickness of 0.2-0.4 mm and a width of 30-40 mm.
[0035] The working principle of the utility model is:
[0036] Before the foil cast coil 1 is wound, the inner insulating layer 2 is placed first, and then the inner lead row 4 is placed. The inner lead row 4 needs to be wrapped with a first glass fiber felt 8, and the wrapping height of the first glass fiber felt 8 is the same as the height of the foil cast coil 1. At the same time, the position between the second bend 6 of the inner lead row 4 and the upper end of the foil cast coil 1 needs to be wrapped with a prepreg shrink tape 7. The second glass fiber mesh cloth 11 is filled between the inner insulating layer 2 and the inner lead row 4. The second glass fiber mesh cloth 11 is filled in a stepped manner, and the filling position is 150 mm downward from the upper end of the foil cast coil 1 and 150 mm upward from the lower end. Then, the coil is wound according to the drawing parameter requirements. When the coil is wound to the last turn, the outer lead row 5 is placed first, and the outer lead row 5 is wound. A second glass fiber felt 9 needs to be wrapped on the top, and the wrapping height of the second glass fiber felt 9 is the same as the height of the foil cast coil 1. At the same time, the position between the second bend 6 of the outer lead row 5 and the upper end of the foil cast coil 1 needs to be wrapped with a prepreg shrink tape 7. The first glass fiber mesh cloth 10 is filled between the outer insulating layer 3 and the outer lead row 5. The first glass fiber mesh cloth 10 is filled in a stepped manner, and the filling position is 150 mm downward and 150 mm upward from the upper end of the foil cast coil 1. An outer insulating layer 3 is laid flat on the outside of the second glass fiber felt 9 to further support and reinforce the outer lead row 5. The outside of the outer insulating layer 3 is also wrapped with a third glass fiber mesh cloth 12 to further improve the insulation strength and mechanical properties of the outer surface of the foil-wound cast coil.
Claims
1. A foil-wound cast coil lead row insulation structure, comprising a foil cast coil (1), wherein the inner surface and the outer surface of the foil cast coil (1) are respectively provided with an inner insulation layer (2) and an outer insulation layer (3), and the foil material of the foil cast coil (1) is respectively provided with an inner lead row (4) and an outer lead row (5), wherein: The positions between the second bend (6) of the inner lead row (4) and the outer lead row (5) and the top of the foil cast coil (1) are wrapped with prepreg shrink tape (7), and the positions of the inner lead row (4) and the outer lead row (5) at the same height as the foil cast coil (1) are wrapped with a first glass felt (8) and a second glass felt (9), respectively; The second glass fiber felt (9) is wrapped with an outer insulating layer (3), and a first glass fiber mesh cloth (10) is filled between the outer insulating layer (3) and the outer lead row (5); and a second glass fiber mesh cloth (11) is filled between the inner insulating layer (2) and the inner lead row (4).
2. The foil-wound cast coil lead row insulation structure according to claim 1, characterized in that: The outer portion of the outer insulating layer (3) is also wrapped with a third glass fiber mesh cloth (12).
3. The foil-wound cast coil lead row insulation structure according to claim 1, characterized in that: The prepreg shrink tape (7) is wrapped in two layers in a half-folded manner, and the wrapping position is between 5 to 10 mm below the second bend (6) and flush with the upper end of the foil casting coil (1).
4. The foil-wound cast coil lead row insulation structure according to claim 1, characterized in that: The heights of the first glass fiber felt (8) and the second glass fiber felt (9) are the same as the height of the foil cast coil (1), and their widths are three times the widths of the inner lead row (4) and the outer lead row (5).
5. The foil-wound cast coil lead row insulation structure according to claim 1, characterized in that: The first glass fiber mesh cloth (10) and the second glass fiber mesh cloth (11) are both filled in a stepped manner, with the filling positions being 150 mm below the upper end of the foil casting coil (1) and 150 mm above the lower end.
6. The foil-wound cast coil lead row insulation structure according to claim 1, characterized in that: The outer insulating layer (3) is a polyester tape or a non-woven tape with a thickness of 0.2 to 0.3 mm and a width of 30 to 50 mm.
7. The foil-wound cast coil lead row insulation structure according to claim 1 or 3, characterized in that: The prepreg shrink tape (7) has a thickness of 0.2 to 0.4 mm and a width of 30 to 40 mm.