Shielding structure of semiconductor angle ring and transformer

Abstract

The invention discloses a shielding structure of a semiconductor angle ring and a transformer. The shielding structure comprises a shielding angle ring, an internal grounding shielding layer and an external grounding shielding layer, the top and the bottom of the internal grounding shielding layer are respectively provided with a shielding angle ring, and the internal grounding shielding layer and the external grounding shielding layer form a surrounding structure. The shielding angle ring comprises a first forming insulating positive angle ring, a semiconductor forming angle ring and a second forming insulating positive angle ring which are sequentially arranged from outside to inside; under the synergistic effect of the internal grounding shielding layer, the external grounding shielding layer and the shielding angle ring, a full-wrapping type electric shielding structure for the low-voltage winding is formed; according to the structure, electromagnetic interference among the low-voltage winding, the iron core, the oil tank and other components can be isolated in all directions, and the influence of the external electromagnetic environment on the accuracy of the trigger pulse of the thyristor is effectively reduced; according to the semiconductor forming angle ring designed by the invention, the ground capacitance of the low-voltage winding can be effectively increased, and the anti-interference capability of the low-voltage winding and the rectifier cabinet is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and particularly to a shielding structure for a semiconductor angle ring and a transformer. Background Art

[0002] The large-capacity voltage-regulating rectifier transformer used in the electrolytic aluminum industry is composed of a voltage-regulating transformer and a rectifier transformer. To save energy and reduce consumption, the voltage-regulating transformer adopts a step-down autotransformer circuit form, and the rectifier transformer has also been changed from the old diode rectification method with a saturated reactor structure to a thyristor rectification method without a saturated reactor.

[0003] Therefore, there is a direct electrical connection between the high-voltage side of the rectifier transformer and the high-voltage side of the voltage-regulating transformer, and the thyristors in the thyristor rectifier cabinet require accurate and reliable trigger pulses. This mode is prone to interference from the regulator. In addition, if a breakdown occurs between the high-voltage side and the low-voltage side of the rectifier transformer, the high voltage will directly invade the rectification system, which will cause damage to the thyristors.

[0004] Therefore, there is an urgent need for a structure that can improve the anti-interference ability of the low-voltage winding (valve-side winding) and avoid the risk of high-voltage intrusion. Traditional shielding layers usually cover the entire winding system and it is difficult to independently shield a single or part of the windings in the transformer. For example, when the secondary power supply system needs to draw power from part of the secondary winding of the transformer, other windings in the high-voltage state may cause potential safety hazards through electromagnetic coupling, resulting in high voltage intruding into the low-voltage circuit, threatening personal safety and the stable operation of equipment.

[0005] CN219591239U discloses a shielded wound-core distribution transformer, which only sets a shielding layer (in the gap between the high-voltage and low-voltage windings) between the high-voltage winding and the low-voltage winding. It belongs to the planar shielding between windings and mainly aims at the electromagnetic coupling and harmonic transmission between the overall windings. It does not provide a full-wrap independent shielding for the low-voltage winding (valve-side winding), and cannot isolate the electromagnetic interference between the inside of the low-voltage winding and components such as the iron core and the fuel tank, nor can it avoid the risk of high-voltage intrusion when a local fault occurs in the low-voltage winding. When part of the winding needs to be independently led out from the low-voltage winding (such as the thyristor rectification system in the electrolytic aluminum industry), the traditional shielding between windings cannot specifically protect the specific area on the low-voltage side.

[0006] Patent CN105280362A introduces a coil shielding device and a transformer with this device. Its core technology is to shield the windings of the transformer coil by setting an annular shielding box. However, the annular shielding box can only cover the circumferential outer side of the winding, but cannot cover the axial ends and the inner side of the winding. This structure can only shield the outer side (high-voltage side), and there is no shielding layer on the inner side (iron-core side), so it cannot achieve a full-wrap electrical shielding. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a shielding structure for a semiconductor horn ring and a transformer, aiming to solve the problems in the background art.

[0008] To achieve the above object, the present invention provides the following technical solution: A shielding structure for a semiconductor horn ring, comprising: a shielding horn ring, an internal grounding shielding layer, and an external grounding shielding layer; a shielding horn ring is respectively arranged at the top and bottom of the internal grounding shielding layer, and forms an enclosing structure with the external grounding shielding layer; The shielding horn ring includes a first formed insulating positive horn ring, a semiconductor formed horn ring, and a second formed insulating positive horn ring arranged in sequence from outside to inside. A shielding horn ring grounding wire is arranged between the semiconductor formed horn ring and the second formed insulating positive horn ring, and the shielding horn ring grounding wire extends out from the end of the shielding horn ring; a plurality of open conductive rings are arranged on the part of the shielding horn ring grounding wire between the semiconductor formed horn ring and the second formed insulating positive horn ring.

[0009] Furthermore, the open conductive ring is composed of an inner-layer open copper ring assembly and an outer-layer open copper ring assembly. The diameter of the inner-layer open copper ring assembly is smaller than that of the outer-layer open copper ring assembly. The inner-layer open copper ring assembly is arranged inside the outer-layer open copper ring assembly, and the two are connected by a connecting copper sheet; a lead wire is arranged on the outer-layer open copper ring assembly for connection with the shielding horn ring grounding wire.

[0010] Furthermore, the shielding horn ring at the top of the internal grounding shielding layer leads out a shielding horn ring top grounding wire, and the shielding horn ring at the bottom of the internal grounding shielding layer leads out a shielding horn ring bottom grounding wire; the top and bottom of the internal grounding shielding layer respectively lead out an internal grounding shielding layer top grounding wire and an internal grounding shielding layer bottom grounding wire; an external grounding shielding layer bottom grounding wire is led out from the external grounding shielding layer; the shielding horn ring top grounding wire, the shielding horn ring bottom grounding wire, the internal grounding shielding layer top grounding wire, the internal grounding shielding layer bottom grounding wire, and the external grounding shielding layer bottom grounding wire are grounded through a main grounding wire.

[0011] Furthermore, the internal grounding shielding layer is composed of a first insulating paperboard, a second insulating paperboard, and an internal grounding shielding layer conductor arranged between the first insulating paperboard and the second insulating paperboard; the top and bottom of the internal grounding shielding layer conductor respectively lead out an internal grounding shielding layer top grounding wire and a shielding horn ring bottom grounding wire.

[0012] Furthermore, the first formed insulating positive horn ring and the second formed insulating positive horn ring have the same structure, and are both formed by combining a plurality of split formed horn rings into a whole circle. Each split formed horn ring covers two positions, and the split horn rings overlap each other by about 50 mm.

[0013] Furthermore, the internal grounding shielding layer conductor and the shielding horn ring are staggered with each other by 50 mm in height.

[0014] A transformer with a shielding structure using a semiconductor corner ring, comprising: a transformer core, a high-voltage winding, and a low-voltage winding; an internal grounding shield layer is provided between the high-voltage winding and the low-voltage winding; a shielding corner ring is respectively provided at the top and bottom of the low-voltage winding, and the shielding corner ring is connected to the internal grounding shield layer; an external grounding shield layer is provided outside the low-voltage winding.

[0015] Furthermore, a preset spacing is provided between the internal grounding shield layer and the low-voltage winding; the size of the preset spacing is determined according to the insulation level of the low-voltage winding to the ground.

[0016] Compared with the existing technology, the present invention has the following beneficial effects:

[0017] (1) Through the synergistic effect of the internal grounding shield layer, the external grounding shield layer and the shielding corner ring, the present invention forms a full-wrap electrical shielding structure for the low-voltage winding; this structure can isolate the electromagnetic interference between the low-voltage winding and components such as the iron core and the oil tank in all directions, effectively reducing the influence of the external electromagnetic environment on the accuracy of the thyristor trigger pulse, and ensuring the stable operation of the thyristor rectification system.

[0018] (2) The semiconductor-formed corner ring designed in the present invention can effectively increase the capacitance of the low-voltage winding to the ground, improving the anti-interference ability of the low-voltage winding and the rectifier cabinet; the corner ring wraps the end of the internal grounding shield layer, shielding the concentrated electric field at the tip of the end of the internal grounding shield layer, making the electric field magnitude at the end of the internal grounding shield layer almost zero directly, so there is no requirement for the curvature radius of the end metal layer, and it is easier to manufacture; and since there is no requirement for the curvature radius, a larger curvature (above 20 mm) can be set. According to the approximate calculation formula of the electric field strength, the surface electric field strength is greatly reduced, increasing the reliability of insulation.

[0019] (3) Through the design that the conductor of the internal grounding shield layer and the shielding corner ring are staggered by 50 mm in height, the present invention avoids the phenomenon of electric field concentration between the high-voltage coil and the shield layer, making the electric field distribution in the entire winding area more uniform, and further improving the anti-interference performance.

[0020] (4) Through the grounding design of the grounding shield layer and the external grounding shield layer, when a breakdown occurs between the high-voltage side and the low-voltage side of the rectifier transformer, the high-voltage charge can be quickly introduced into the ground, completely preventing the high voltage on the network side from directly invading the rectification system, preventing the thyristor from being damaged due to high-voltage impact, and at the same time avoiding the high voltage from sneaking into the low-voltage circuit and threatening personal safety.

[0021] (5) For scenarios such as the electrolytic aluminum industry that require power extraction from specific regions of the low-voltage winding, the present invention designs a fully enclosed shielding structure to provide targeted protection for specific regions of the low-voltage winding. Even if there is electromagnetic coupling with other windings in a high-voltage state, the shielding layer can effectively block energy transfer and prevent potential safety hazards. The fully enclosed shielding structure significantly increases the capacitance to ground of the low-voltage winding, optimizes the insulation characteristics of the winding, enabling it to better withstand voltage fluctuations and transient overvoltages during system operation, and reducing the risk of insulation breakdown. Description of the Drawings

[0022] Figure 1 Schematic diagram of the installation of the shielding structure of the present invention.

[0023] Figure 2 Schematic diagram of the shielding angle ring structure of the present invention.

[0024] Figure 3 Schematic diagram of the open conductive ring structure of the present invention.

[0025] Figure 4 Front view of the internal grounding shielding layer of the present invention.

[0026] Figure 5 Side view of the internal grounding shielding layer of the present invention.

[0027] Figure 6 Electric field distribution diagram at the end of the transformer without a semiconductor-molded angle ring and without the high-voltage winding incoming line.

[0028] Figure 7 Electric field distribution diagram at the end of the transformer without a semiconductor-molded angle ring and with the high-voltage winding incoming line.

[0029] Figure 8 Electric field distribution diagram at the end of the transformer of the present invention without the high-voltage winding incoming line.

[0030] Figure 9 Electric field distribution diagram at the end of the transformer of the present invention with the high-voltage winding incoming line.

[0031] In the figures, 1. Transformer core; 2. High-voltage winding; 3. Low-voltage winding; 4. Shielding angle ring; 5. Top grounding wire of the shielding angle ring; 6. Top grounding wire of the internal grounding shielding layer; 7. Internal grounding shielding layer; 8. External grounding shielding layer; 9. Bottom grounding wire of the external grounding shielding layer; 10. Bottom grounding wire of the internal grounding shielding layer; 11. Bottom grounding wire of the shielding angle ring; 12. First molded insulating positive angle ring; 13. Semiconductor-molded angle ring; 14. Open conductive ring; 15. Second molded insulating positive angle ring; 16. Lead wire; 17. Connecting copper sheet; 18. Inner layer open copper ring assembly; 19. Outer layer open copper ring assembly; 20. Conductor of the internal grounding shielding layer; 21. First insulating cardboard; 22. Second insulating cardboard. Detailed implementation mode

[0032] As Figure 1 shown, the present invention provides a technical solution: a shielding structure for a semiconductor horn ring, including: a shielding horn ring 4, an internal grounding shielding layer 7 and an external grounding shielding layer 8; a shielding horn ring 4 is respectively arranged at the top and bottom of the internal grounding shielding layer 7, and forms an enclosing structure with the external grounding shielding layer 8.

[0033] As Figure 2 shown, the shielding horn ring 4 includes a first molded insulating positive horn ring 12, a semiconductor molded horn ring 13 and a second molded insulating positive horn ring 15 which are arranged in sequence from outside to inside. A shielding horn ring grounding wire is arranged between the semiconductor molded horn ring 13 and the second molded insulating positive horn ring 15, and the shielding horn ring grounding wire extends out from the end of the shielding horn ring 4; a plurality of open conductive rings 14 are arranged on the part of the shielding horn ring grounding wire between the semiconductor molded horn ring 13 and the second molded insulating positive horn ring 15.

[0034] As Figure 3 shown, the open conductive ring 14 is composed of an inner layer open copper ring assembly 18 and an outer layer open copper ring assembly 19. The diameter of the inner layer open copper ring assembly 18 is smaller than that of the outer layer open copper ring assembly 19. The inner layer open copper ring assembly 18 is arranged inside the outer layer open copper ring assembly 19, and the two are connected by a connecting copper sheet 17; a lead wire 16 is arranged on the outer layer open copper ring assembly 19 for connecting with the shielding horn ring grounding wire.

[0035] Among them, the shielding horn ring 4 at the top of the internal grounding shielding layer 7 leads out a shielding horn ring top grounding wire 5, and the shielding horn ring 4 at the bottom of the internal grounding shielding layer 7 leads out a shielding horn ring bottom grounding wire 11; the top and bottom of the internal grounding shielding layer 7 respectively lead out an internal grounding shielding layer top grounding wire 6 and an internal grounding shielding layer bottom grounding wire 10; an external grounding shielding layer bottom grounding wire 9 is led out from the external grounding shielding layer 8; the shielding horn ring top grounding wire 5, the shielding horn ring bottom grounding wire 11, the internal grounding shielding layer top grounding wire 6, the internal grounding shielding layer bottom grounding wire 10 and the external grounding shielding layer bottom grounding wire 9 are grounded through a main grounding wire.

[0036] As Figure 4 、 Figure 5 shown, the internal grounding shielding layer 7 is composed of a first insulating paperboard 21, a second insulating paperboard 22 and an internal grounding shielding layer conductor 20 arranged between the first insulating paperboard 21 and the second insulating paperboard 22; the top and bottom of the internal grounding shielding layer conductor 20 respectively lead out an internal grounding shielding layer top grounding wire 6 and a shielding horn ring bottom grounding wire 11.

[0037] Among them, the internal grounding shielding layer conductor 20 and the shielding horn ring 4 are staggered with each other by 50 mm in height.

[0038] Among them, the overall structure of the external grounding shield layer 8 is similar to that of the internal grounding shield layer 7, but only one bottom grounding wire 9 of the external grounding shield layer is provided.

[0039] Among them, the first formed insulating positive angle ring 12 and the second formed insulating positive angle ring 15 have the same structure, and are both formed by combining a plurality of divided formed angle rings (referred to as divided angle rings) into a complete circle. Each divided angle ring covers two positions, and the divided angle rings overlap each other by about 50 mm.

[0040] Among them, the semiconductor formed angle ring 13 is similar in structure to the first formed insulating positive angle ring 12 and the second formed insulating positive angle ring 15, but the material is semiconductor paper containing carbon powder, and its manufacturing process is the same as that of the traditional divided angle ring; to ensure the semiconductor conductivity, it is necessary to ensure that the two-point test resistance value of 1 m is less than 1 M ohm.

[0041] Among them, to avoid the phenomenon of electric field concentration between the high-voltage winding 2 and the internal grounding shield layer 7, the internal grounding shield layer conductor 20 and the semiconductor formed angle ring 13 should be staggered by 50 mm in height.

[0042] A transformer adopting the shielding structure of the semiconductor angle ring includes: a transformer core 1, a high-voltage winding 2 and a low-voltage winding 3; an internal grounding shield layer 7 is arranged between the high-voltage winding 2 and the low-voltage winding 3; a shielding angle ring 4 is respectively arranged at the top and bottom of the low-voltage winding 3, and the shielding angle ring 4 is connected to the internal grounding shield layer 7; an external grounding shield layer 8 is arranged outside the low-voltage winding 3; the high-voltage winding 2 includes a phase-shifting coil, a basic coil, or only one high-voltage coil; the low-voltage winding 3 is composed of low-voltage coils.

[0043] Among them, the distance between the internal grounding shield layer 7 and the low-voltage winding 3 is set to 7 mm to 10 mm; the size of the distance is determined according to the insulation level of the low-voltage winding 3 to the ground.

[0044] Among them, after completing the assembly work of the coils and insulation, that is, after sleeving the high-voltage winding 2, the low-voltage winding 3, the shielding angle ring 4, the internal grounding shield layer 7, and the external grounding shield layer 8 on the transformer core 1, it is necessary to connect all the top grounding wires (the top grounding wire 5 of the shielding angle ring and the top grounding wire 6 of the internal grounding shield layer) together and do a good job of insulation wrapping. It is also necessary to connect all the bottom grounding wires (the bottom grounding wire 9 of the external grounding shield layer, the bottom grounding wire 10 of the internal grounding shield layer, and the bottom grounding wire 11 of the shielding angle ring) together and do a good job of insulation wrapping. Finally, according to the position of the grounding point on the clamp of the transformer core 1, select the top grounding wire or the bottom grounding wire to connect with the grounding point on the clamp of the transformer core 1.

[0045] Simulation experiment.

[0046] Such asFigures 6-7 As shown in the figure, an external voltage withstand test was carried out on a transformer without the semiconductor molded corner ring 13 designed by the present invention. The voltages applied to the basic coil and the phase-shifting coil were 200 kV, and the low-voltage coil was directly grounded. The main electric field of the transformer was simulated and calculated by the computer finite element method.

[0047] The electric field intensity at the tip of the end of the grounding shield layer is very large, and the magnitude of the electric field intensity is directly related to the electrode curvature radius of the internal grounding shield layer 7: ; In the formula, represents the maximum electric field intensity; represents the applied voltage; represents the distance between the two electrodes; represents the electrode curvature radius.

[0048] The computer simulation results show that the maximum value of the electric field intensity at the tip of the grounding shield layer is 15 kV / mm - 20 kV / mm ( Figure 7 at the grounding shield layer corresponding to the end of the basic coil lead), and the maximum value of the electric field intensity at the tip of the grounding shield layer in the remaining parts is 8 kV / mm - 10 kV / mm. The electric field intensity concentration coefficient is closely related to the electrode curvature radius r at the end of the grounding shield layer electrode; the electric field intensity concentration coefficient in the non-lead area is also closely related to the height of the grounding shield layer electrode. Since the grounding shield layer is usually made of a very thin copper strip, it is very difficult to make its electrode curvature radius r more than 0.5 mm, so the electric field concentration phenomenon is very serious.

[0049] As Figures 8-9 shown in the figure, an external voltage withstand test was carried out on the transformer including the present invention. The voltages applied to the basic coil and the phase-shifting coil were 200 kV, and the low-voltage coil and the shield layer were both directly grounded. The computer simulation results show that: the maximum electric field occurs at the bending part of the semiconductor molded corner ring 13 ( Figure 9 at the grounding shield layer corresponding to the end of the basic coil lead); the maximum electric field intensity is only 5 kV / mm - 5.5 kV / mm; the electric field intensity concentration coefficient has little relationship with the curvature radius of the semiconductor molded corner ring 13 (curvature radius ≥ 20 mm).

[0050] Since the curvature radius at the bending part of the semiconductor molded corner ring 13 is very large (more than 20 mm), according to the approximate calculation formula of the electric field intensity, the surface electric field intensity is greatly reduced, increasing the reliability of the insulation.

[0051] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A shielding structure for a semiconductor corner ring, characterized in that, Comprising: A shielding angle ring, an internal grounding shield layer, and an external grounding shield layer; a shielding angle ring is respectively arranged at the top and bottom of the internal grounding shield layer, and forms an enclosed structure with the external grounding shield layer; The shielding angle ring includes a first formed insulating positive angle ring, a semiconductor formed angle ring, and a second formed insulating positive angle ring arranged in sequence from outside to inside. A shielding angle ring grounding wire is arranged between the semiconductor formed angle ring and the second formed insulating positive angle ring, and the shielding angle ring grounding wire extends out from the end of the shielding angle ring; several open conductive rings are arranged on the part of the shielding angle ring grounding wire between the semiconductor formed angle ring and the second formed insulating positive angle ring.

2. The shielding structure of a semiconductor angle ring according to claim 1, characterized in that: The open conductive ring is composed of an inner layer open copper ring assembly and an outer layer open copper ring assembly. The diameter of the inner layer open copper ring assembly is smaller than that of the outer layer open copper ring assembly. The inner layer open copper ring assembly is arranged inside the outer layer open copper ring assembly, and the two are connected by a connecting copper sheet; a lead wire is arranged on the outer layer open copper ring assembly for connection with the shielding angle ring grounding wire.

3. The shielding structure of a semiconductor angle ring according to claim 2, characterized in that: The shielding angle ring at the top of the internal grounding shield layer leads out the shielding angle ring top grounding wire, and the shielding angle ring at the bottom of the internal grounding shield layer leads out the shielding angle ring bottom grounding wire; the top and bottom of the internal grounding shield layer respectively lead out the internal grounding shield layer top grounding wire and the internal grounding shield layer bottom grounding wire; the external grounding shield layer leads out the external grounding shield layer bottom grounding wire; The shielding angle ring top grounding wire, the shielding angle ring bottom grounding wire, the internal grounding shield layer top grounding wire, the internal grounding shield layer bottom grounding wire, and the external grounding shield layer bottom grounding wire are grounded through a main grounding wire.

4. The shielding structure of a semiconductor angle ring according to claim 3, characterized in that: The internal grounding shield layer is composed of a first insulating paperboard, a second insulating paperboard, and an internal grounding shield layer conductor arranged between the first insulating paperboard and the second insulating paperboard; the top and bottom of the internal grounding shield layer conductor respectively lead out the internal grounding shield layer top grounding wire and the shielding angle ring bottom grounding wire.

5. The shielding structure of a semiconductor angle ring according to claim 4, characterized in that: The first formed insulating positive angle ring and the second formed insulating positive angle ring have the same structure, and are both formed by combining multiple split formed angle rings into a complete circle. Each split formed angle ring covers two positions, and the split angle rings overlap each other by 50 mm.

6. The shielding structure of a semiconductor angle ring according to claim 5, characterized in that: The internal grounding shield layer conductor and the shielding angle ring are staggered by 50 mm in height.

7. A transformer, adopting the shielding structure of the semiconductor angle ring as described in any one of claims 1-6, characterized in that, Comprising: A transformer core, a high-voltage winding, and a low-voltage winding; An internal grounding shield layer is arranged between the high-voltage winding and the low-voltage winding; a shielding angle ring is respectively arranged at the top and bottom of the low-voltage winding, and the shielding angle ring is connected to the internal grounding shield layer; an external grounding shield layer is arranged outside the low-voltage winding.

8. A transformer according to claim 7, characterized in that: A preset spacing is provided between the internal grounding shield layer and the low-voltage winding; the size of the preset spacing is determined according to the insulation level of the low-voltage winding to the ground.

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