Bendable end magnetic shield structure for avoiding coil wire and method thereof

Abstract

The application provides a bendable end magnetic shielding structure capable of avoiding coil outgoing lines and a method thereof. The bendable end magnetic shielding structure capable of avoiding coil outgoing lines comprises a three-phase coil, the three-phase coil comprises a core and a coil wound outside the core, the upper and lower portions of the core are fixed with fixing frames, the upper and lower portions of the fixing frames located at the high-voltage side and the low-voltage side of the three-phase coil are fixed with magnetic shielding assemblies, the magnetic shielding assemblies comprise a plurality of shielding strips made of silicon steel sheets, and the outermost shielding strips in each magnetic shielding assembly are welded with grounding copper strips. The shielding strips constituting the magnetic shielding assemblies are made of silicon steel sheets and parallel to magnetic lines, can maximize the absorption of leakage magnetic, reduce the leakage magnetic into the metal components of the core clamp and the oil tank wall, reduce the stray loss, limit the eddy current generated by the leakage magnetic in the silicon steel sheets within the thickness of the silicon steel sheets, and maximize the reduction of the stray loss of the magnetic shielding itself.

Description

TECHNICAL FIELD

[0001] The present application relates to a flexible end magnetic shielding structure for avoiding coil outlet and a method thereof. BACKGROUND

[0002] When the transformer coil is in operation, leakage magnetic flux will flow along the space occupied by the coil and the surrounding space. When the leakage magnetic flux passes through the metal components such as the wire, the core clamp, the oil tank wall, etc., an electric current will also be formed inside the metal components, which will generate a magnetic flux in the opposite direction to resist the leakage magnetic flux. The electric current inside the metal components is called eddy current, which will generate stray loss. In order to reduce the stray loss, the traditional method is to paste silicon steel sheets on the oil tank wall. By using the high permeability and low unit loss characteristics of the silicon steel sheets, the leakage magnetic flux is guided to enter the steel plate components such as the core clamp and the oil tank wall as little as possible. However, the amount of magnetic shielding on the oil tank wall is large, and it will make the leakage magnetic field of the coil end more curved, increasing the transverse leakage magnetic component. Moreover, the magnetic shielding on the oil tank wall will increase the length and width of the oil tank to ensure sufficient electrical insulation distance. SUMMARY

[0003] The present application improves the above problems, that is, the technical problem to be solved by the present application is that when the transformer coil is in operation, leakage magnetic flux will flow along the space occupied by the coil and the surrounding space. The existing magnetic shielding method will make the leakage magnetic field of the coil end more curved, increasing the transverse leakage magnetic component and increasing the overall volume.

[0004] The specific embodiment of the present application is: a flexible end magnetic shielding structure for avoiding coil outlet, comprising a three-phase coil, the three-phase coil comprising a core and a coil wound outside the core, a fixed frame is fixed to the upper part and the lower part of the core, a magnetic shielding assembly is fixed to the upper part and the lower part of the three-phase coil high voltage side and low voltage side of the fixed frame, the magnetic shielding assembly comprises a plurality of shielding strips made of silicon steel sheets, and a grounding copper strip is welded to the outermost shielding strip in each magnetic shielding assembly.

[0005] Further, an upper supporting plate is fixed to the top of the fixed frame on the high voltage side and the low voltage side of the three-phase coil, an upper pressing plate is fixed above the upper supporting plate, the magnetic shielding assembly on the upper part of the high voltage side and the low voltage side is fixed between the upper supporting plate and the upper pressing plate, a lower pressing plate is fixed to the bottom of the fixed frame on the high voltage side and the low voltage side of the three-phase coil, a lower supporting plate is fixed below the lower pressing plate, and the magnetic shielding assembly on the lower part of the high voltage side and the low voltage side is fixed between the lower supporting plate and the lower pressing plate.

[0006] Further, high-strength crepe paper is wrapped on the surface of the shielding strip of each magnetic shielding assembly, and a heat shrinkable tape is wrapped outside the high-strength crepe paper to prevent the shielding strip from loosening.

[0007] Further, the upper surface of the lower supporting plate and the lower surface of the upper pressing plate have grooves for placing the magnetic shielding assembly.

[0008] Further, the high-strength corrugated paper is in the form of a groove covering the inner surface of the magnetic shielding assembly in the groove.

[0009] Further, the main air channel is left between the inner side of the fixing frame and the coil, the upper and lower parts of the fixing frame extend to limit the iron core clamps, and the groove includes an arc-shaped part in contact with the main air channel.

[0010] Further, the upper supporting plate has an opening on the inner side of the low-pressure side for leading out the low-pressure wire.

[0011] Further, the bolt is connected to the same potential through the grounding copper strip and the iron core clamp.

[0012] Further, the magnetic shielding assembly includes 4-8 shielding strips, the thickness of the shielding strip is 0.2-0.3 mm, and the width is 8-10 mm.

[0013] Further, the grounding copper strip has a thickness of 0.1-0.3 mm and a width of 6-8 mm, and the overlapping length of the grounding copper strip and the shielding strip is 25-30 mm.

[0014] The application also includes a method for bending the end of the magnetic shielding to avoid the coil wire, which uses the above-mentioned magnetic shielding structure to embed the shielding strip into the layer groove in parallel with the iron core clamp, the groove is arranged along the main air channel of the coil, the shielding strip is completely embedded in the groove and the groove-shaped high-strength corrugated paper is covered on the top of the magnetic shielding assembly, the groove-shaped high-strength corrugated paper, the shielding strip and the heat shrinkable tape are bundled together to prevent the shielding strip from loosening, and the grounding hole is provided on the outer end of the grounding copper strip to connect the grounding copper strip and the fixing frame by means of the bolt penetrating through the grounding hole.

[0015] Compared with the prior art, the application has the following beneficial effects:

[0016] 1. The magnetic shielding is close to the area with the strongest magnetic leakage in the coil, which can maximize the absorption of magnetic leakage and reduce the magnetic leakage into the iron core clamp and the metal components of the oil tank wall, thereby reducing the stray loss.

[0017] 2. The magnetic shielding is located at the end of the coil, which can attract magnetic leakage and reduce the bending of the magnetic lines of force at the end of the coil, thereby reducing the stray loss caused by the transverse magnetic leakage of the coil.

[0018] 3. The magnetic shielding uses a structure shared by three-phase coils, which can utilize the characteristic that the phases of the magnetic leakage of the three-phase coils differ by 120° to neutralize and cancel the magnetic leakage in the magnetic shielding.

[0019] 4The shielding bar constituting the magnetic shielding assembly is made of the shielding bar and parallel to the magnetic force line, the eddy current generated by the magnetic leakage in the shielding bar is limited in the range of the thickness of the shielding bar, and the stray loss of the magnetic shielding itself can be maximally reduced.

[0020] 5The shielding bar is made of thin silicon steel sheets and has good bending ability, can well avoid the coil lead-out wire, and is attached to the main air channel of the coil, and the ability of absorbing the magnetic leakage of the coil can be effectively improved.

[0021] 6Easy to install, the magnetic shielding is installed on the horizontal plane, and only the shielding bar is embedded in the laminated wood groove, and the tank magnetic shielding tank wall can reduce 80% of the work.

[0022] 7The amount is saved, and the amount of the end magnetic shielding is only about 1 / 3 of the tank magnetic shielding.

[0023] 8The oil tank space is saved, compared with the tank magnetic shielding, the width of the oil tank is reduced by about 50mm, thereby saving about 3% of the transformer oil and about 1% of the steel plate.

[0024] 9Compared with the tank magnetic shielding, only the magnetic leakage on the side of the coil is blocked, the clamp magnetic shielding can block the magnetic leakage on the upper and lower parts of the coil, and the magnetic leakage can be more effectively reduced, and the stray loss of the transformer can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present application.

[0026] Figure 2 It is a structural schematic diagram of the present application Figure 1 Top view.

[0027] Figure 3 It is a structural schematic diagram of the present application Figure 1 Side view.

[0028] Figure 4 It is a structural schematic diagram of the present application Figure 1 D enlarged structural schematic diagram.

[0029] Figure 5 It is a structural schematic diagram of the present application Figure 3 E enlarged structural schematic diagram.

[0030] Figure 6 It is a structural schematic diagram of the present application

[0031] Figure 7 It is a structural schematic diagram of the present application

[0032] Figure 8 It is a structural schematic diagram of the present application

[0033] Figure 9The high-voltage side lower supporting plate structure of the present application is shown in the figure. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0035] As Figures 1-9 shown, the bendable end magnetic shielding structure avoiding the coil outlet includes three-phase coils, the three-phase coils include a core 101 and a coil 102 wound outside the core, the upper and lower parts of the core 101 are fixed with fixed frames 10, the upper and lower parts of the fixed frames 10 located at the high-voltage side and the low-voltage side of the three-phase coils are fixed with magnetic shielding assemblies 20, the magnetic shielding assemblies include a plurality of shielding strips 210 made of silicon steel sheets, and the outermost shielding strips in each magnetic shielding assembly are welded with grounding copper strips 220.

[0036] In the embodiment, the magnetic shielding assemblies are arranged at the upper and lower ends of the high-voltage side and the low-voltage side of the three-phase coils, and there are four magnetic shielding assemblies in total. The leakage magnetic fluxes of the three-phase coils of the transformer have a phase difference of 120°, and when they enter the end magnetic shielding, the three-phase leakage magnetic fluxes are synthesized and offset each other, thereby reducing the magnetic flux passing through the core clamp wrapped outside the core and the oil tank wall.

[0037] In the embodiment, the fixed frames 10 are fixed with upper supporting plates 310 at the top of the high-voltage side and the low-voltage side of the three-phase coils, and the upper supporting plates are fixed with upper pressing plates 320 above, the magnetic shielding assemblies at the upper parts of the high-voltage side and the low-voltage side are fixed between the upper supporting plates and the upper pressing plates, the fixed frames are fixed with lower pressing plates 410 at the bottom of the high-voltage side and the low-voltage side of the three-phase coils, and the lower pressing plates are fixedly connected with lower supporting plates 420 below, and the magnetic shielding assemblies at the lower parts of the high-voltage side and the low-voltage side are fixed between the lower supporting plates and the lower pressing plates.

[0038] In the embodiment, the magnetic shielding assembly includes 4-8 shielding strips 210, the thickness of the shielding strips is 0.2-0.3 mm, and the width is 8-10 mm. In actual design, the shielding strips adopt oriented silicon steel sheets with thickness specifications of 0.23 mm, 0.27 mm, 0.3 mm, etc. as raw materials. The width of each shielding strip can be 10 mm, and the length is determined according to the size of the three-phase coils of the transformer.

[0039] In the embodiment, the upper surface of the lower supporting plate 420 and the lower surface of the upper pressing plate 320 have grooves 50 for placing the magnetic shielding assemblies.

[0040] In the embodiment, the width of the groove 50 is adjusted according to the number of the embedded shielding strips, and is generally between 44 mm and 86 mm, and the depth is 12 mm.

[0041] In this embodiment, the surface of the shielding strip of each magnetic shielding assembly is wrapped with high-strength crepe paper 60, and the high-strength crepe paper is wrapped with a heat-shrinkable tape 70 to prevent the shielding strip from loosening.

[0042] In this embodiment, the high-strength crepe paper is groove-shaped and covers the inner surface of the magnetic shielding assembly in the groove.

[0043] In this embodiment, a main air channel 103 is left between the inner side of the fixing frame and the coil, the upper and lower parts of the fixing frame extend iron core clamps 104 for limiting the iron core, and the groove 50 includes an arc-shaped part that is in contact with the main air channel.

[0044] In this embodiment, the upper supporting plate has an opening 105 on the inner side of the low-voltage side for the low-voltage lead-out wire 106.

[0045] In this embodiment, the bolt passes through the grounding copper tape and the iron core clamp for equipotential connection.

[0046] In this embodiment, the grounding copper tape has a thickness of 0.1mm to 0.3mm and a width of 6mm to 8mm, and the overlapping length of the grounding copper tape and the shielding strip is 25mm to 30mm.

[0047] During installation, the shielding strip is embedded into the layer groove 50 in a way that the iron core clamp is parallel, the groove on the high-voltage side is arranged along the main air channel of the coil as much as possible, and is in line with the maximum magnetic leakage area of the coil; the groove on the low-voltage side is moved to the high-voltage coil area appropriately in the area where the lead wire passes through, and the rest of the part is still in contact with the main air channel of the coil as much as possible. The shielding strip is completely embedded into the groove and covered with groove-shaped high-strength crepe paper 60 above the magnetic shielding assembly, and the groove-shaped high-strength crepe paper 60, the shielding strip, and the heat-shrinkable tape are bundled together to prevent the shielding strip from loosening.

[0048] In this embodiment, the groove-shaped high-strength crepe paper 60 is folded from a 1.0mm thick electrical paper board, the groove-shaped high-strength crepe paper 60 is 10mm deep, 1mm smaller in width than the slot, and 10mm longer than the shielding strip, the length direction of the groove-shaped high-strength crepe paper 60 can be spliced, the outermost shielding strip in the magnetic shielding assembly is welded with a grounding copper tape 220, the grounding hole 221 at the outer end of the grounding copper tape 220, and the bolt passing through the grounding hole is used to realize the equipotential connection between the grounding copper tape 220 and the iron core clamp.

[0049] If the present application discloses or relates to mutually fixedly connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachably fixedly connected (for example, connected using bolts or screws), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, manufactured by integral forming using a casting process) (obviously, integral forming process cannot be used).

[0050] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the present application include states or shapes similar, similar or close to them, unless otherwise stated.

[0051] Any component provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by integral forming process.

[0052] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or some technical features can be replaced by equivalents; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application claimed.

Claims

1. An end magnetic shield structure that can bend to avoid a coil outgoing wire, characterized by, The three-phase coil comprises a core and a coil wound outside the core, the upper and lower portions of the core are fixed with fixing frames, the upper and lower portions of the fixing frames on the high-voltage side and the low-voltage side of the three-phase coil are fixed with magnetic shielding assemblies, the magnetic shielding assemblies comprise a plurality of shielding strips made of silicon steel sheets, and the outermost shielding strips in each magnetic shielding assembly are welded with a grounding copper strip; The surfaces of the shielding strips of each magnetic shielding assembly are wrapped with high-strength crepe paper, and the high-strength crepe paper is wrapped with a heat-shrinkable tape to prevent the shielding strips from loosening; The high-strength crepe paper is in a groove shape and covers the inner surface of the magnetic shielding assembly in the groove; The inside of the fixing frame and the coil are left with a main air channel, the upper and lower portions of the fixing frame extend iron core clamps for limiting the iron core, and the groove comprises an arc-shaped portion in contact with the main air channel; The top of the fixing frame on the high-voltage side and the low-voltage side of the three-phase coil is fixed with an upper supporting plate, the upper supporting plate is fixed with an upper pressing plate above, the magnetic shielding assemblies on the upper portions of the high-voltage side and the low-voltage side are fixed between the upper supporting plate and the upper pressing plate, the bottom of the fixing frame on the high-voltage side and the low-voltage side of the three-phase coil is fixed with a lower pressing plate, the lower pressing plate is fixedly connected with a lower supporting plate below, and the magnetic shielding assemblies on the lower portions of the high-voltage side and the low-voltage side are fixed between the lower supporting plate and the lower pressing plate; The upper surface of the lower supporting plate and the lower surface of the upper pressing plate have grooves for placing the magnetic shielding assemblies.

2. The end magnetic shield structure of claim 1, wherein The inside of the upper supporting plate on the low-voltage side is left with an opening for a low-voltage outgoing line.

3. The end magnetic shield structure of claim 1, wherein, The bolt is connected in the same potential through the grounding copper strip and the iron core clamp.

4. The end magnetic shield structure of claim 1, wherein The magnetic shielding assembly comprises 4-8 shielding strips, the thickness of the shielding strips is 0.2-0.3 mm, the width is 8-10 mm, the thickness of the grounding copper strip is 0.1-0.3 mm, the width is 6-8 mm, and the overlapping length of the grounding copper strip and the shielding strip is 25-30 mm.

5. An end magnetic shielding method of a bendable wire avoiding a coil wire, characterized by, The shielding strips are embedded into the layer groove in parallel with the iron core clamp, the groove is arranged along the main air channel of the coil, the shielding strips are all embedded into the groove, the groove-shaped high-strength crepe paper covers the upper portion of the magnetic shielding assembly, the groove-shaped high-strength crepe paper and the shielding strips and the heat-shrinkable tape are bundled together to prevent the shielding strips from loosening, the outer end of the grounding copper strip has a grounding hole, and the grounding copper strip and the fixing frame are connected by a bolt penetrating through the grounding hole.

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