A shielding structure of semiconductor corner ring and transformer

Abstract

The present invention discloses a shielding structure of a semiconductor angle ring and a transformer, the shielding structure comprising: a shielding angle ring, an internal grounding shielding layer and an external grounding shielding layer; a shielding angle ring is respectively provided on the top and bottom of the internal grounding shielding layer, and forms an enclosing structure with the external grounding shielding layer; the shielding angle ring comprises a first molded insulating positive angle ring, a semiconductor molded angle ring and a second molded insulating positive angle ring which are sequentially arranged from the outside to the inside; the present invention forms a fully enclosed electric shielding structure for the low-voltage winding through the coordinated action of the internal grounding shielding layer, the external grounding shielding layer and the shielding angle ring; this structure can fully isolate the electromagnetic interference between the low-voltage winding and components such as the iron core and the oil tank, and effectively reduce the influence of the external electromagnetic environment on the accuracy of the thyristor trigger pulse; the semiconductor molded angle ring designed in the present invention can effectively increase the capacitance of the low-voltage winding to the ground, and improve the anti-interference ability of the low-voltage winding and the rectifier cabinet.

Description

Technical Field

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

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

[0003] Therefore, there's a direct electrical connection between the high-voltage side of the rectifier transformer and the high-voltage side of the voltage regulator. The thyristors within the thyristor rectifier cabinet require precise and reliable trigger pulses, making this model susceptible to interference from the regulator. Furthermore, if a breakdown occurs between the high-voltage and low-voltage sides of the rectifier transformer, the high voltage will directly intrude into the rectifier system, damaging the thyristors.

[0004] Therefore, there is an urgent need for a method that can improve the low-voltage winding's (valve-side winding's) anti-interference capabilities and prevent the risk of high-voltage intrusion. Traditional shielding typically covers the entire winding system, making it difficult to independently shield individual or partial windings within the transformer. For example, when the secondary power supply system requires power from a portion of the transformer's secondary winding, the remaining high-voltage windings could pose a safety hazard through electromagnetic coupling, causing high voltage to enter the low-voltage circuit, threatening personal safety and equipment stability.

[0005] CN219591239U discloses a shielded wound-core distribution transformer. This transformer features only a single shielding layer between the high-voltage and low-voltage windings (located within the gap between them). This is a planar inter-winding shield, primarily designed to prevent electromagnetic coupling and harmonic transmission between the windings. The low-voltage winding (valve-side winding) is not fully shielded, effectively isolating the internal low-voltage winding from electromagnetic interference from components such as the core and fuel tank. This also fails to prevent the risk of high-voltage intrusion in the event of a localized low-voltage winding fault. When a portion of the low-voltage winding requires independent extraction (such as in thyristor rectifier systems in the electrolytic aluminum industry), conventional inter-winding shielding cannot specifically protect specific areas on the low-voltage side.

[0006] Patent CN105280362A describes a coil shielding device and a transformer incorporating the device. Its core technology involves shielding the transformer coil windings using an annular shielding box. However, the annular shielding box only covers the circumferential outer side of the windings, but not the axial ends or the inner side. This structure only shields the outer side (high-voltage side), while the inner side (core side) lacks a shielding layer, making it impossible to achieve full electrical shielding. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the present invention provides a shielding structure of a semiconductor corner ring and a transformer, the purpose of which is to solve the problems in the background technology.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solution: a shielding structure for a semiconductor corner ring, comprising: a shielding corner ring, an internal grounding shielding layer, and an external grounding shielding layer; a shielding corner ring is provided at the top and bottom of the internal grounding shielding layer, respectively, and forms an enclosing structure with the external grounding shielding layer;

[0009] The shielding angle ring includes a first molded insulating positive angle ring, a semiconductor molded angle ring and a second molded insulating positive angle ring arranged in sequence from the outside to the inside. A shielding angle ring grounding wire is arranged between the semiconductor molded angle ring and the second molded insulating positive angle ring, and the shielding angle ring grounding wire extends from the end of the shielding angle ring; a plurality of open conductive rings are arranged on the part of the shielding angle ring grounding wire between the semiconductor molded angle ring and the second molded insulating positive angle ring.

[0010] Furthermore, the open conductive ring is composed of an inner open copper ring assembly and an outer open copper ring assembly. The diameter of the inner open copper ring assembly is smaller than that of the outer open copper ring assembly. The inner open copper ring assembly is arranged in the outer open copper ring assembly, and the two are connected by a connecting copper sheet; a lead wire is provided on the outer open copper ring assembly for connecting to the shielding angle ring grounding wire.

[0011] Furthermore, the shielding angle ring at the top of the internal grounding shielding layer leads out the top grounding wire of the shielding angle ring, and the shielding angle ring at the bottom of the internal grounding shielding layer leads out the bottom grounding wire of the shielding angle ring; the top and bottom of the internal grounding shielding layer lead out the top grounding wire of the internal grounding shielding layer and the bottom grounding wire of the internal grounding shielding layer respectively; the bottom grounding wire of the external grounding shielding layer is led out on the external grounding shielding layer; the top grounding wire of the shielding angle ring, the bottom grounding wire of the shielding angle ring, the top grounding wire of the internal grounding shielding layer, the bottom grounding wire of the internal grounding shielding layer and the bottom grounding wire of the external grounding shielding layer are grounded through the main grounding wire.

[0012] Furthermore, the internal grounding shielding layer is composed of a first insulating cardboard, a second insulating cardboard, and an internal grounding shielding layer conductor arranged between the first insulating cardboard and the second insulating cardboard; the top and bottom of the internal grounding shielding layer conductor respectively lead out the top grounding wire of the internal grounding shielding layer and the bottom grounding wire of the shielding angle ring.

[0013] Furthermore, the first molded insulating positive angle ring and the second molded insulating positive angle ring have the same structure, both of which are composed of multiple petal molded angle rings combined into a complete circle, each petal molded angle ring covers two gears, and the petal angle rings overlap with each other by about 50mm.

[0014] Furthermore, the inner ground shielding layer conductor and the shielding angle ring are staggered by 50 mm in height.

[0015] A transformer adopts a shielding structure using semiconductor angle rings, comprising: a transformer core, a high-voltage winding and a low-voltage winding; an internal grounding shielding 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 rings are connected to the internal grounding shielding layer; an external grounding shielding layer is arranged on the outside of the low-voltage winding.

[0016] Furthermore, a preset distance is set between the internal ground shielding layer and the low-voltage winding; the size of the preset distance is determined according to the insulation level of the low-voltage winding to the ground.

[0017] Compared with the existing technology, the present invention has the following beneficial effects:

[0018] (1) The present invention forms a fully enclosed electric shielding structure for the low-voltage winding through the synergistic effect of the internal grounding shielding layer, the external grounding shielding layer and the shielding angle ring; this structure can fully isolate the electromagnetic interference between the low-voltage winding and the iron core, oil tank and other components, effectively reduce the influence of the external electromagnetic environment on the accuracy of the thyristor trigger pulse, and ensure the stable operation of the thyristor rectifier system.

[0019] (2) The semiconductor formed angle ring designed in the present invention can effectively increase the capacitance of the low-voltage winding to the ground, and improve the anti-interference ability of the low-voltage winding and the rectifier cabinet; the angle ring covers the end of the internal grounding shielding layer to shield the concentrated electric field at the tip of the end of the internal grounding shielding layer, so that the electric field size of the end of the internal grounding shielding layer is directly close to zero, so the curvature radius of the metal layer at its end does not need to be required, and it is easier to manufacture; and since there is no requirement for the curvature radius, a larger curvature (more than 20mm) can be set. According to the approximate calculation formula of the electric field strength, its surface electric field strength is greatly reduced, which increases the reliability of the insulation.

[0020] (3) The present invention avoids the electric field concentration phenomenon between the high-voltage coil and the shielding layer by designing that the internal grounding shielding layer conductor and the shielding angle ring are staggered by 50 mm in height, making the electric field distribution in the entire winding area more uniform and further improving the anti-interference performance.

[0021] (4) The present invention uses a grounding design of a grounding shield layer and an 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 conducted to the ground, completely preventing the high voltage on the grid side from directly invading the rectifier system, preventing the thyristor from being damaged by the high-voltage shock, and preventing the high voltage from entering the low-voltage circuit and threatening personal safety.

[0022] (5) The present invention is aimed at scenarios such as the electrolytic aluminum industry where power needs to be drawn from a part of the low-voltage winding. The fully enclosed shielding structure is designed to provide targeted protection for specific areas of the low-voltage winding. Even if electromagnetic coupling occurs in other windings in a high-voltage state, the shielding layer can effectively block energy transfer and prevent the occurrence of safety hazards. The fully enclosed shielding structure significantly increases the capacitance of the low-voltage winding to the ground and optimizes the insulation characteristics of the winding, enabling it to better withstand voltage fluctuations and transient overvoltages during system operation and reduce the risk of insulation breakdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the installation of the shielding structure of the present invention.

[0024] Figure 2 This is a schematic diagram of the shielding angle ring structure of the present invention.

[0025] Figure 3 Schematic diagram of the open conductive ring structure of the present invention.

[0026] Figure 4 This is the main view of the internal ground shielding layer of the present invention.

[0027] Figure 5 It is a side view of the internal ground shielding layer of the present invention.

[0028] Figure 6 This is the electric field distribution diagram at the transformer end when there is no semiconductor formed angle ring and no high-voltage winding incoming line.

[0029] Figure 7 This is the electric field distribution diagram at the transformer end when there is no semiconductor formed angle ring and high-voltage winding incoming line.

[0030] Figure 8 This is the electric field distribution diagram at the end of the transformer of the present invention when there is no high-voltage winding incoming line.

[0031] Figure 9 This is the electric field distribution diagram at the end of the transformer with high-voltage winding when it is connected to the transformer.

[0032] In the figure, 1. Transformer core; 2. High-voltage winding; 3. Low-voltage winding; 4. Shielding angle ring; 5. Top grounding wire of shielding angle ring; 6. Top grounding wire of internal grounding shield layer; 7. Internal grounding shield layer; 8. External grounding shield layer; 9. Bottom grounding wire of external grounding shield layer; 10. Bottom grounding wire of internal grounding shield layer; 11. Bottom grounding wire of 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 open copper ring assembly; 19. Outer open copper ring assembly; 20. Internal grounding shield layer conductor; 21. First insulating cardboard; 22. Second insulating cardboard. DETAILED DESCRIPTION

[0033] like Figure 1 As shown, the present invention provides a technical solution: a shielding structure of a semiconductor corner ring, comprising: a shielding corner ring 4, an internal grounding shielding layer 7 and an external grounding shielding layer 8; a shielding corner ring 4 is respectively provided on the top and bottom of the internal grounding shielding layer 7, and forms an enclosing structure with the external grounding shielding layer 8.

[0034] like Figure 2 As shown, the shielding angle ring 4 includes a first molded insulating positive angle ring 12, a semiconductor molded angle ring 13 and a second molded insulating positive angle ring 15 arranged in sequence from the outside to the inside, a shielding angle ring grounding wire is arranged between the semiconductor molded angle ring 13 and the second molded insulating positive angle ring 15, and the shielding angle ring grounding wire extends from the end of the shielding angle ring 4; a plurality of open conductive rings 14 are arranged on the portion of the shielding angle ring grounding wire between the semiconductor molded angle ring 13 and the second molded insulating positive angle ring 15.

[0035] like Figure 3 As shown, the open conductive ring 14 is composed of an inner open copper ring assembly 18 and an outer open copper ring assembly 19. The diameter of the inner open copper ring assembly 18 is smaller than that of the outer open copper ring assembly 19. The inner open copper ring assembly 18 is arranged in the outer open copper ring assembly 19, and the two are connected by a connecting copper sheet 17; the outer open copper ring assembly 19 is provided with a lead wire 16 for connecting to the shielding angle ring grounding wire.

[0036] Among them, the shielding angle ring 4 at the top of the internal grounding shielding layer 7 leads out the shielding angle ring top grounding wire 5, and the shielding angle ring 4 at the bottom of the internal grounding shielding layer 7 leads out the shielding angle ring bottom grounding wire 11; the top and bottom of the internal grounding shielding layer 7 respectively lead out the internal grounding shielding layer top grounding wire 6 and the internal grounding shielding layer bottom grounding wire 10; the external grounding shielding layer bottom grounding wire 9 is led out on the external grounding shielding layer 8; the shielding angle ring top grounding wire 5, the shielding angle 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 the main grounding wire.

[0037] like Figure 4 、 Figure 5 As shown, the internal ground shielding layer 7 is composed of a first insulating paperboard 21, a second insulating paperboard 22, and an internal ground shielding layer conductor 20 arranged between the first insulating paperboard 21 and the second insulating paperboard 22; the top and bottom of the internal ground shielding layer conductor 20 respectively lead to the internal ground shielding layer top grounding wire 6 and the shielding angle ring bottom grounding wire 11.

[0038] The inner ground shielding layer conductor 20 and the shielding angle ring 4 are staggered with each other by 50 mm in height.

[0039] The overall structure of the external ground shielding layer 8 is similar to that of the internal ground shielding layer 7 , but only one grounding wire 9 is provided at the bottom of the external ground shielding layer.

[0040] Among them, the first molded insulating positive angle ring 12 and the second molded insulating positive angle ring 15 have the same structure. Both are composed of multiple petal molded angle rings (referred to as petal angle rings) combined into a whole circle. Each petal angle ring covers two gears, and the petal angle rings overlap with each other by about 50mm.

[0041] Among them, the semiconductor molded angle ring 13 is similar in structure to the first molded insulating positive angle ring 12 and the second molded insulating positive angle ring 15, but its material is semiconductor paper containing carbon powder, and its manufacturing process is consistent with the traditional petal angle ring; in order to ensure the conductive performance of the semiconductor, it is necessary to ensure that the double-point test resistance value of 1m is less than 1M ohm.

[0042] In order to avoid electric field concentration between the high-voltage winding 2 and the internal ground shielding layer 7, the internal ground shielding layer conductor 20 and the semiconductor forming angle ring 13 should be staggered by 50 mm in height.

[0043] A transformer adopting the shielding structure of the semiconductor angle ring comprises: a transformer core 1, a high-voltage winding 2 and a low-voltage winding 3; an internal grounding shielding layer 7 is arranged between the high-voltage winding 2 and the low-voltage winding 3; a shielding angle ring 4 is respectively arranged on the top and bottom of the low-voltage winding 3, and the shielding angle ring 4 is connected to the internal grounding shielding layer 7; an external grounding shielding layer 8 is arranged on the outside of 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 a low-voltage coil.

[0044] The distance between the internal ground shielding 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.

[0045] Among them, after completing the assembly of the coil and insulation, that is, after the high-voltage winding 2, the low-voltage winding 3, the shielding angle ring 4, the internal grounding shielding layer 7, and the external grounding shielding layer 8 are installed 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, the top grounding wire 6 of the internal grounding shielding layer) together and insulate them. It is also necessary to connect all the bottom grounding wires (the bottom grounding wire 9 of the external grounding shielding layer, the bottom grounding wire 10 of the internal grounding shielding layer, and the bottom grounding wire 11 of the shielding angle ring) together and insulate them. Finally, according to the position of the grounding point on the transformer core 1 clamp, select the top grounding wire or the bottom grounding wire to connect to the grounding point on the transformer core 1 clamp.

[0046] Simulation experiment.

[0047] like Figure 6-Figure 7 As shown, a transformer without the semiconductor formed angle ring 13 designed by the present invention is subjected to an external withstand voltage test, wherein the voltage applied to the basic coil and the phase shift coil is 200kV, and the low-voltage coil is directly grounded; the computer finite element method is used to simulate and calculate the main electric field of the transformer.

[0048] The electric field intensity at the tip of the ground shield layer is very large, and the magnitude of the electric field intensity is directly related to the curvature radius of the electrode of the internal ground shield layer 7:

[0049] ;

[0050] Where, Indicates the maximum electric field strength; represents the applied voltage; Represents the distance between two electrodes; Indicates the electrode curvature radius.

[0051] Computer simulation results show that the maximum electric field strength at the tip of the ground shield is 15kV / mm~20kV / mm ( Figure 7 The maximum electric field strength at the ground shield tip (corresponding to the basic coil exit) is 8kV / mm to 10kV / mm. The electric field concentration factor is closely related to the curvature radius r of the ground shield electrode tip. The electric field concentration factor in non-exit areas is also closely related to the height of the ground shield electrode. Because the ground shield is typically made of very thin copper tape, achieving an electrode curvature radius r exceeding 0.5mm is difficult, resulting in significant electric field concentration.

[0052] like Figure 8-Figure 9 As shown, a transformer including the present invention was subjected to an external withstand voltage test, wherein the voltage applied to the basic coil and the phase-shifting coil was 200 kV, and the low-voltage coil and the shielding layer were directly grounded; computer simulation results show that the maximum electric field occurs at the bend of the semiconductor forming angle ring 13 ( Figure 9 The ground shield layer corresponding to the basic coil exits); the maximum electric field strength is only 5kV / mm~5.5kV / mm; the electric field concentration coefficient has little to do with the curvature radius of the semiconductor forming angle ring 13 (curvature radius ≧20mm).

[0053] Since the curvature radius of the semiconductor forming angle ring 13 at the bend is large (more than 20 mm), according to the approximate calculation formula of the electric field strength, the surface electric field strength is greatly reduced, thereby increasing the insulation reliability.

[0054] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A shielding structure of a semiconductor corner ring, characterized in that: include: A shielding angle ring, an internal grounding shielding layer and an external grounding shielding layer; a shielding angle ring is provided on the top and bottom of the internal grounding shielding layer respectively, and forms an enclosing structure with the external grounding shielding layer; The shielding angle ring includes a first molded insulating positive angle ring, a semiconductor molded angle ring, and a second molded insulating positive angle ring, which are arranged in sequence from the outside to the inside. A shielding angle ring grounding wire is provided between the semiconductor molded angle ring and the second molded insulating positive angle ring, and the shielding angle ring grounding wire extends from the end of the shielding angle ring; a portion of the shielding angle ring grounding wire between the semiconductor molded angle ring and the second molded insulating positive angle ring is provided with a plurality of open conductive rings; The open conductive ring is composed of an inner open copper ring assembly and an outer open copper ring assembly. The inner open copper ring assembly has a smaller diameter than the outer open copper ring assembly. The inner open copper ring assembly is arranged inside the outer open copper ring assembly, and the two are connected by a connecting copper sheet. The outer open copper ring assembly is provided with a lead wire for connecting to the shielding angle ring ground wire. The shielding angle ring at the top of the internal grounding shielding layer leads to the top grounding wire of the shielding angle ring, and the shielding angle ring at the bottom of the internal grounding shielding layer leads to the bottom grounding wire of the shielding angle ring; the top and bottom of the internal grounding shielding layer lead to the top grounding wire of the internal grounding shielding layer and the bottom grounding wire of the internal grounding shielding layer respectively; the bottom grounding wire of the external grounding shielding layer is led out of the external grounding shielding layer; The top grounding wire of the shielding angle ring, the bottom grounding wire of the shielding angle ring, the top grounding wire of the internal grounding shield layer, the bottom grounding wire of the internal grounding shield layer, and the bottom grounding wire of the external grounding shield layer are grounded through the main grounding wire.

2. The shielding structure of a semiconductor corner ring according to claim 1, characterized in that: 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 the top grounding wire of the internal grounding shielding layer and the bottom grounding wire of the shielding angle ring.

3. The shielding structure of a semiconductor corner ring according to claim 2, characterized in that: The first molded insulating positive angle ring and the second molded insulating positive angle ring have the same structure, and are both formed by combining multiple petal molded angle rings into a complete circle, and the petal angle rings overlap each other by 50 mm.

4. The shielding structure of a semiconductor corner ring according to claim 3, characterized in that: The inner ground shielding layer conductor and the shielding angle ring are staggered by 50 mm in height.

5. A transformer, using the shielding structure of the semiconductor angle ring according to any one of claims 1 to 4, characterized in that: include: Transformer core, high voltage winding and low voltage winding; An internal grounding shielding layer is provided between the high-voltage winding and the low-voltage winding; a shielding angle ring is provided at the top and bottom of the low-voltage winding respectively, and the shielding angle ring is connected to the internal grounding shielding layer; an external grounding shielding layer is provided on the outside of the low-voltage winding.

6. A transformer according to claim 5, characterized in that: There is a preset distance between the internal ground shielding layer and the low-voltage winding; the size of the preset distance is determined according to the insulation level of the low-voltage winding to the ground.

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