Grounding screen for axial double-split rectifier transformer

Abstract

The grounding screen is arranged between a high-voltage coil and a low-voltage coil and comprises first insulation paper and a copper foil area connected to the first insulation paper, and the copper foil area comprises a first branch copper foil area and a second branch copper foil area which are arranged at intervals in the height direction. A spacer region is arranged between the first sub-copper foil region and the second sub-copper foil region, and the arrangement position of the spacer region corresponds to the interval position of the two low-voltage coils which are arranged at an interval in the axial direction; each of the first sub-copper foil area and the second sub-copper foil area comprises a plurality of arranged copper foil strips, the copper foil strips are wrapped with insulating layers, the first sub-copper foil area is provided with a first grounding lead connected with the copper foil strips, and the second sub-copper foil area is provided with a second grounding lead connected with the copper foil strips. According to the grounding screen for the axial double-split rectifier transformer, the high-voltage coil and the low-voltage coil are effectively and electrically isolated, and expensive rectifying equipment on the low-voltage side is effectively protected.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and in particular to a grounding shield for an axial double-split rectifier transformer. Background Technology

[0002] In modern industrial enterprises, electricity is widely used as an energy source. DC power is particularly prevalent in many industries such as metallurgy, electrochemicals, traction, transmission, and DC power transmission. Converting alternating current (AC) to direct current (DC) requires a rectifier. A rectifier transformer is used in this rectifier. Placing a grounding shield between the valve-side winding and the grid-side winding of the rectifier transformer effectively prevents interference from the power grid, thus protecting the expensive valve-side rectifier. In recent years, with the development and maturation of foil winding technology, double-split rectifier transformers increasingly adopt axial split structures. Therefore, providing a grounding shield suitable for axially split double-split rectifier transformers has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0003] In view of this, the present invention provides a grounding shield for an axial double-split rectifier transformer, which effectively isolates the high-voltage coil and the low-voltage coil, and effectively protects the expensive rectifier equipment on the low-voltage side.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A grounding shield for an axially split rectifier transformer is disposed between a high-voltage coil and a low-voltage coil. It includes a first insulating paper and a copper foil area connected to the first insulating paper. The copper foil area includes a first sub-copper foil area and a second sub-copper foil area spaced apart along the height direction. A gap is provided between the first and second sub-copper foil areas, and the location of the gap corresponds to the spacing between the two low-voltage coils spaced apart along the axial direction. Each of the first and second sub-copper foil areas includes several arranged copper foil strips, each wrapped with an insulating layer. The first sub-copper foil area is provided with a first grounding lead connected to the copper foil strips, and the second sub-copper foil area is provided with a second grounding lead connected to the copper foil strips.

[0006] Optionally, the height of the interval region is greater than the distance between the interval positions of the two axially arranged low-voltage coils.

[0007] Optionally, the plurality of copper foil strips on the first copper foil area and / or the second copper foil area are arranged along the height direction of the first insulating paper.

[0008] Optionally, the insulating layer is a second insulating paper, which is at least wrapped around the surfaces of two adjacent copper foil strips that are close to each other.

[0009] Optionally, the second insulating paper has an opening at the location where the copper foil strip connects to the grounding lead.

[0010] Optionally, a third insulating paper is connected to the interval area, and the third insulating paper fills the interval area.

[0011] Optionally, the total thickness of the third insulating paper is not less than the thickness of the first copper foil area or the second copper foil area;

[0012] The third insulating paper is adhered to the copper foil strip.

[0013] Optionally, a fourth insulating paper is adhered to the surface of the insulating layer away from the first insulating paper;

[0014] The fourth insulating paper has two layers and a thickness of 0.08 mm.

[0015] Optionally, a fifth insulating paper is laid on the surface of the fourth insulating paper away from the insulating layer;

[0016] A sixth insulating paper is laid on the surface of the first insulating paper away from the copper foil area;

[0017] The fifth insulating paper has three layers, and the sixth insulating paper has two layers. When the fifth and sixth insulating papers are bent into a tube, their two closest ends overlap.

[0018] Optionally, the first grounding lead includes a first copper strip and a first soft copper braid connected together, wherein the first copper strip is welded to the copper foil strip of the first copper foil section;

[0019] The second grounding lead includes a second copper strip and a second soft copper braid connected together, with the second copper strip welded to the copper foil strip of the second copper foil section.

[0020] As can be seen from the above technical solution, the grounding shield for the axial double-split rectifier transformer provided by the present invention divides the copper foil into two parts: a first copper foil area and a second copper foil area. This ensures that the copper foil area in the grounding shield avoids the high leakage magnetic field area in the middle, preventing additional losses and heat generation caused by the copper foil area being located in the high leakage magnetic field area. This protects the low-voltage side of the transformer and avoids unnecessary burn-out faults. By setting copper foil strips in both the first and second copper foil areas, and connecting the copper foil strips to the first or second grounding lead, a low-resistance discharge channel is formed. This allows static electricity or leakage current to be quickly conducted to the ground through the grounding lead, preventing charge accumulation that could cause sparks or damage to sensitive components, and significantly reducing partial discharge. An insulating layer is wrapped around the copper foil strips to insulate and isolate adjacent copper foil strips, avoiding current caused by the electromotive force difference between different copper foil strips. The multiple copper foil strips arranged on the grounding shield, compared to a large copper film sheet, are easier to source, save costs, and reduce the probability of eddy currents generated by electromagnetic induction, thereby reducing the probability of heat generation in the copper foil area. The grounding shield for the axial double-split rectifier transformer of the present invention effectively isolates the high-voltage coil and the low-voltage coil electrically, so that there is only magnetic connection between the high-voltage coil and the low-voltage coil, and no electrical connection, thereby preventing the power grid from interfering with the rectifier equipment and effectively protecting the expensive rectifier equipment on the low-voltage side. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A partial structural diagram of a grounding screen for an axially split rectifier transformer, provided in an embodiment of the present invention, is shown between the high-voltage coil and the low-voltage coil.

[0023] Figure 2 This is a schematic diagram of the structure of a grounding screen for an axial double-split rectifier transformer at one angle, provided in an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the grounding screen for an axially split rectifier transformer from another angle, provided in an embodiment of the present invention.

[0025] Figure 4 for Figure 3 A partial cross-sectional view of the AA position;

[0026] Figure 5 This is a schematic diagram of the structure of the second insulating paper wrapped on the copper foil strip at one angle according to an embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of another angle at which the second insulating paper is wrapped on the copper foil strip, according to an embodiment of the present invention.

[0028] Figure 7 A schematic diagram of the structure of the grounding screen with copper foil strips adhered to the first insulating paper provided in an embodiment of the present invention (the first insulating paper is unfolded).

[0029] Figure 8 for Figure 7 A schematic diagram of the structure after the third insulating paper is bonded to the spacer area.

[0030] in:

[0031] 100, grounding shield; 200, low-voltage coil; 300, high-voltage coil.

[0032] 1. Sixth insulating paper; 2. Third insulating paper; 3. First grounding lead; 301. First copper strip; 302. First flexible copper braid; 303. First terminal block; 4. Second grounding lead; 401. Second copper strip; 402. Second flexible copper braid; 403. Second terminal block; 5. Copper foil area; 501. First sub-copper foil area; 502. Second sub-copper foil area; 6. Fifth insulating paper; 7. First insulating paper; 8. Copper foil strip; 9. Second insulating paper; 10. Fourth insulating paper; 11. Opening; 12. Spacing area. Detailed Implementation

[0033] This invention discloses a grounding shield for an axial double-split rectifier transformer, which effectively isolates the high-voltage coil and the low-voltage coil, and effectively protects the expensive rectifier equipment on the low-voltage side.

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Reference Figures 1 to 8The grounding shield 100 for the axially split rectifier transformer of the present invention is disposed between the high-voltage coil 300 and the low-voltage coil 200. The grounding shield 100 includes a first insulating paper 7 and a copper foil area 5 connected to the first insulating paper 7. The low-voltage coil 200 includes two coils spaced apart along the axial direction. The copper foil area 5 includes a first copper foil area 501 and a second copper foil area 502 spaced apart along the height direction of the first insulating paper 7. A gap area 12 is provided between the first copper foil area 501 and the second copper foil area 502, and the position of the gap area 12 corresponds to the gap position of the two low-voltage coils 200. Both the first copper foil area 501 and the second copper foil area 502 include a plurality of copper foil strips 8 arranged in a row, and the copper foil strips 8 are covered with an insulating layer. The first copper foil area 501 is provided with a first grounding lead 3 connected to the copper foil strips 8, and the second copper foil area 502 is provided with a second grounding lead 4 connected to the copper foil strips 8.

[0036] The height direction of the first insulating paper 7 refers to the height direction of the grounding shield 100 in its operating state, such as... Figure 2 The first copper foil area 501 is located at the upper part of the spacing area 12, and the second copper foil area 502 is located at the lower part of the spacing area 12. The first insulating paper 7 is bent into a tube, and the ends that are close to each other after bending are spaced apart. When spaced apart, the spacing distance is D2, and the range of D2 is 20-40mm.

[0037] The grounding shield 100 for the axial double-split rectifier transformer of the present invention divides the copper foil area 5 into two parts: a first copper foil area 501 and a second copper foil area 502. This ensures that the copper foil area in the grounding shield avoids the high leakage magnetic field area in the middle, preventing additional losses and heat generation caused by the copper foil area being located in the high leakage magnetic field area. This protects the low-voltage side of the transformer and avoids unnecessary burn-out faults. Copper foil strips 8 are provided in both the first and second copper foil areas 501 and 502, and the copper foil strips 8 are connected to the first grounding lead 3 or the second grounding lead 4 to form a low-resistance discharge channel. This allows static electricity or leakage current to be quickly conducted to the ground through the grounding lead, preventing charge accumulation that could cause sparks or damage to sensitive components, and significantly reducing partial discharge. An insulating layer is wrapped around the copper foil strips 8 to insulate and isolate adjacent copper foil strips 8, preventing current caused by the electromotive force difference between different copper foil strips 8. The grounding shield 100 is provided with multiple copper foil strips 8 arranged in a specific pattern. Compared with a large copper film sheet, this method is easier to procure, saves costs, and reduces the probability of eddy currents generated by electromagnetic induction, thereby reducing the probability of heat generation in the copper foil area. The grounding shield 100 for the axial double-split rectifier transformer of the present invention effectively isolates the high-voltage coil 300 and the low-voltage coil 200 electrically, so that there is only a magnetic connection between the high-voltage coil 300 and the low-voltage coil 200, and no electrical connection. This prevents the power grid from interfering with the rectifier equipment and effectively protects the expensive rectifier equipment on the low-voltage side.

[0038] In one specific embodiment, the height D4 of the interval 12 is greater than the distance D1 between the two axially arranged low-voltage coils 200, thereby avoiding the setting of the first copper foil area 501 and the second copper foil area 502 on the first insulating paper 7, which would affect the magnetic connection between the high-voltage coil 300 and the low-voltage coil 200.

[0039] To avoid excessive electromotive force difference due to magnetic flux, the copper foil strips 8 are arranged along the height of the first insulating paper 7 in the first copper foil area 501 or the second copper foil area 502, i.e., the long sides of the copper foil strips 8 are horizontal. In another embodiment, the long sides of the copper foil strips 8 in both the first copper foil area 501 and the second copper foil area 502 are horizontal.

[0040] In one embodiment, the insulating layer is a second insulating paper 9, which is applied to at least the surfaces of two adjacent copper foil strips 8 that are close to each other. To improve the efficiency and positional reliability of the second insulating paper 9 applied to the copper foil strips 8, the second insulating paper 9 can be applied in a C-shape to the copper foil strips 8, such as... Figure 5 As shown. In this embodiment, the second insulating paper 9 does not completely cover the copper foil strip 8, thus leaving an opening 11 extending along the length of the copper foil strip 8 at the connection point between the copper foil strip 8 and the grounding lead. In other embodiments, the second insulating paper 9 can also completely cover the copper foil strip 8, leaving only a gap at the connection point between the copper foil strip 8 and the grounding lead. Specifically, the side of the copper foil strip 8 covered with the second insulating paper 9 that has the opening 11 is adhered to the first insulating paper 7, such as... Figure 4 As shown. Figure 4 The inner side refers to the side of the grounding shield 100 that is bent into a cylindrical shape and is closer to the center of the cylinder, that is, the side that is closer to the high-voltage coil 300.

[0041] To achieve reliable partitioning of the first copper foil area 501 and the second copper foil area 502, and to prevent displacement of the copper foil strip 8, a third insulating paper 2 is connected at the interval 12 position, such as... Figure 8 As shown, the third insulating paper 2 fills the spacer area 12 to prevent the copper foil strip 8 located above the spacer area 12 from shifting downwards. The length and width of the third insulating paper 2 correspond to those of the spacer area 12.

[0042] To improve the reliability of the support, the total thickness of the third insulating paper 2 is not less than the thickness of the first copper foil area 501 or the second copper foil area 502. The thickness of the first copper foil area 501 or the second copper foil area 502 is the total thickness of the copper foil strip 8 after the second insulating paper 9 is applied. To prevent the third insulating paper 2 from falling off the copper foil strip 8, the third insulating paper 2 is adhered to the copper foil strip 8. By setting the third insulating paper 2, adjacent copper foil strips 8 can be separated.

[0043] To ensure the reliability of the insulation and the structural reliability of the grounding shield 100, a fourth insulating paper 10 is adhered to the surface of the insulating layer away from the first insulating paper 7, such as... Figure 4 As shown, the fourth insulating paper 10 has two layers and a thickness of 0.08 mm to avoid the paper layer being too thick and affecting the overall thickness of the grounding screen 100.

[0044] To ensure insulation effectiveness, a fifth insulating paper 6 is laid on the surface of the fourth insulating paper 10 away from the insulating layer. The fifth insulating paper 6 has three layers and a thickness of 0.5 mm. A sixth insulating paper 1 is laid on the surface of the first insulating paper 7 away from the copper foil area 5. The sixth insulating paper 1 has two layers and a thickness of 0.5 mm. When the fifth insulating paper 6 and the sixth insulating paper 1 are bent into a tube, their two closest ends overlap. Furthermore, the overlap positions of the ends of different layers of the fifth insulating paper 6 or the sixth insulating paper 1 are staggered to ensure insulation effectiveness.

[0045] Specifically, the first grounding lead 3 includes a first copper strip 301 and a first soft copper braid 302 connected together, such as... Figure 7 As shown, the end of the first flexible copper braid 302 furthest from the first copper strip 301 is connected to a first terminal 303. The first copper strip 301 is welded to the copper foil strip 8 of the first copper foil section 501. The first terminal 303 is connected to a grounding bolt. The second grounding lead 4 includes a second copper strip 401 and a second flexible copper braid 402 connected together. The end of the second flexible copper braid 402 furthest from the second copper strip 401 is connected to a second terminal 403. The second copper strip 401 is welded to the copper foil strip 8 of the second copper foil section 502. The second terminal 403 is connected to a grounding bolt.

[0046] In the above embodiments, one or more of the first insulating paper 7, the second insulating paper 9, the third insulating paper 2, the fourth insulating paper 10, and the fifth insulating paper 6 can be cable paper.

[0047] In one specific embodiment, the copper foil strip 8 is selected as a strip of copper foil with a thickness of 0.1 mm and a height of 40 mm. Here, the height refers to the dimension of the copper foil strip 8 along the height direction when the first insulating paper 7 is in use. The second insulating paper 9 is a piece of paper with a thickness of 0.12 mm and a height of 60 mm. Here, the height refers to the dimension of the copper foil strip 8 along the height direction when the first insulating paper 7 is in use. After the second insulating paper 9 is wrapped around the copper foil strip 8, the opening 11 left is as follows... Figure 5As shown, the height D3 of opening 11 is approximately 20mm, and opening 11 is adhered to a first insulating paper 7 with a thickness of 0.5mm. The thickness of the third insulating paper 2 is 0.5mm, and the height of the third insulating paper 2 is determined by the spacing between the axially split coils of the low-voltage coil 200. The third insulating paper 2 is adhered to the first insulating paper 7. When the first insulating paper 7 is bent into a tube, the two adjacent ends are spaced apart or overlapped at the edges to prevent the copper foil strip 8 from contacting and forming a closed loop. The first copper strip 301 and the second copper strip 401 are soldered to the copper foil strip 8. The copper strip has a thickness of 0.3mm and a width of 40mm. The soft copper braid is soldered to the copper strip and led out. The soft copper braid is wrapped with insulating crepe paper tape, which is then tied with thin cotton rope and fixed to the insulating paper of the grounding shield 100. Two layers of 0.08mm cable paper are adhered to the second insulating paper 9, and together with the first insulating paper 7, the copper foil strip 8, copper strip, soft copper braid, etc., are wrapped and fixed firmly to prevent displacement.

[0048] The grounding shield 100 for the axially split rectifier transformer of this invention uses strips of copper foil 8 arranged vertically, firmly bonded to the insulating cable paper, pressed flat, and fixed to form an open cylindrical structure. It is rolled up for transport, storage, and use, and cannot be folded. Copper sheets and soft copper braids are welded to the upper and lower ends of the same side of the cylindrical structure as lead wires. The grounding shield 100 is simply placed in the main channel between the high and low voltage coils, i.e., fitted between the oil channel pad and the insulating cylinder, and the axial upper and lower lead wires are led out for grounding. The grounding shield 100 effectively separates the high and low voltage coils, ensuring only magnetic connection and no electrical connection between them, thus effectively protecting the expensive rectifier device on the low-voltage side.

[0049] In the description of this solution, it should be understood that the terms "upper", "lower", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this solution.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this solution, "multiple" means two or more, unless otherwise explicitly specified.

[0051] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0052] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A grounding shield for an axially split rectifier transformer, disposed between the high-voltage coil and the low-voltage coil, characterized in that, The device includes a first insulating paper and a copper foil area connected to the first insulating paper. The copper foil area includes a first sub-copper foil area and a second sub-copper foil area spaced apart along the height direction. A gap is provided between the first sub-copper foil area and the second sub-copper foil area. The location of the gap corresponds to the spacing between the two low-voltage coils spaced apart along the axial direction. Both the first sub-copper foil area and the second sub-copper foil area include a plurality of copper foil strips arranged in a row. The copper foil strips are covered with an insulating layer. The first sub-copper foil area is provided with a first grounding lead connected to the copper foil strips. The second sub-copper foil area is provided with a second grounding lead connected to the copper foil strips.

2. The grounding shield for an axially split rectifier transformer according to claim 1, characterized in that, The height of the interval zone is greater than the distance between the two axially arranged low-voltage coils.

3. The grounding shield for an axially split rectifier transformer according to claim 1, characterized in that, The plurality of copper foil strips on the first copper foil area and / or the second copper foil area are arranged along the height direction of the first insulating paper.

4. The grounding shield for an axial double-split rectifier transformer according to any one of claims 1-3, characterized in that, The insulating layer is a second insulating paper, which is applied to at least the surfaces of two adjacent copper foil strips that are close to each other.

5. The grounding shield for an axially split rectifier transformer according to claim 4, characterized in that, The second insulating paper has an opening at the location where the copper foil strip connects to the grounding lead.

6. The grounding shield for an axially split rectifier transformer according to claim 1, characterized in that, A third insulating paper is connected to the interval area, and the third insulating paper fills the interval area.

7. The grounding shield for an axially split rectifier transformer according to claim 6, characterized in that, The total thickness of the third insulating paper is not less than the thickness of the first copper foil area or the second copper foil area; The third insulating paper is adhered to the copper foil strip.

8. The grounding shield for an axially split rectifier transformer according to claim 1, characterized in that, A fourth insulating paper is adhered to the surface of the insulating layer away from the first insulating paper; The fourth insulating paper has two layers and a thickness of 0.08 mm.

9. The grounding shield for an axially split rectifier transformer according to claim 8, characterized in that, A fifth insulating paper is laid on the surface of the fourth insulating paper away from the insulating layer; A sixth insulating paper is laid on the surface of the first insulating paper away from the copper foil area; The fifth insulating paper has three layers, and the sixth insulating paper has two layers. When the fifth and sixth insulating papers are bent into a tube, their two closest ends overlap.

10. The grounding shield for an axially split rectifier transformer according to claim 1, characterized in that, The first grounding lead includes a first copper strip and a first soft copper braid connected together, wherein the first copper strip is welded to the copper foil strip of the first copper foil section; The second grounding lead includes a second copper strip and a second soft copper braid connected together, with the second copper strip welded to the copper foil strip of the second copper foil section.

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