Split low voltage winding for high impedance transformer

Abstract

The utility model discloses a split type low voltage winding for high impedance transformer, including upper and lower low voltage winding, and upper and lower low voltage winding respectively include insulating cylinder, bracing piece, multiple coils and ground screen, the oil channel set between two adjacent coils or between coil and ground screen, end insulation, the end insulation of upper low voltage winding lower extreme, the end insulation of lower low voltage winding upper extreme is placed in the upper end and lower end of insulating end ring, and the end insulation of upper low voltage winding has upper iron yoke insulation and pressing plate in proper order on, and the end insulation of lower low voltage winding has lower iron yoke insulation and support plate in proper order on the lower end, and the coil of upper and lower low voltage winding most inner end and most outer end leads out terminal I, terminal II, terminal III and terminal IV along the axial direction respectively, and the ground screen of upper and lower low voltage winding leads out terminal V and terminal VI along the axial direction respectively. The high impedance transformer using this low voltage winding can improve the impedance of transformer and reduce the winding temperature rise of transformer.

Description

Technical Field

[0001] This utility model belongs to the field of transformer manufacturing, and specifically relates to a split low-voltage winding for a high-impedance transformer. Technical Background

[0002] High-impedance transformers are crucial equipment in unidirectional power supply systems. Their application allows for simultaneous operation in both reactor and transformer modes, eliminating the need for separate current-limiting reactors to limit short-circuit current, thus reducing equipment investment, floor space, and construction costs. However, the significant additional losses in high-impedance transformers increase winding temperature rise. Therefore, finding a solution that both increases transformer impedance and reduces winding temperature rise is a pressing issue for high-impedance transformers. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned problems in the prior art and provide a split low-voltage winding for high-impedance transformers. High-impedance transformers using this low-voltage winding can both increase transformer impedance and reduce transformer winding temperature rise.

[0004] To achieve the above objectives, the technical solution of this utility model is: a split low-voltage winding for a high-impedance transformer, comprising an upper low-voltage winding and a lower low-voltage winding symmetrically arranged; the upper and lower low-voltage windings each include an insulating cylinder fitted onto an iron core, support bars evenly distributed outside the insulating cylinder, multiple coils concentrically wound outside the support bars, a grounding shield disposed outside the outermost coil, oil channels disposed between two adjacent coils or between a coil and the grounding shield, and end insulation bound and fixed to both ends of the coil and the grounding shield; the end insulation at the lower end of the upper low-voltage winding is placed above the insulating end ring, and the end insulation at the upper end of the lower low-voltage winding... The end insulation is placed at the lower end of the insulating end ring; the upper yoke insulation is placed at the upper end of the end insulation of the upper low-voltage winding, and the pressure plate is placed at the upper end of the upper yoke insulation; the lower yoke insulation is placed at the lower end of the end insulation of the lower low-voltage winding, and the support plate is placed at the lower end of the lower yoke insulation; the innermost coils of the upper and lower low-voltage windings respectively lead out terminal I and terminal II axially upwards and downwards, respectively, and the outermost coils of the two respectively lead out terminal III axially upwards and terminal IV axially downwards, respectively; the grounding shields of the upper and lower low-voltage windings respectively lead out terminal V axially upwards and terminal VI axially downwards, respectively.

[0005] More preferably, the oil passage is provided with rectangular support strips made of laminated insulating paperboard, or with a support strip curtain made of rectangular support strips made of laminated insulating paperboard bonded to cable paper, or with corrugated cardboard made of pressed insulating paperboard.

[0006] More preferably, the grounding shield is made of multiple layers of cable paper in the upper layer, a copper plate in the middle layer and an insulating cardboard in the lower layer, which are stacked together. The copper plate is welded to the upper end with copper braided wire leading out to terminal V or the copper plate is welded to the lower end with copper braided wire leading out to terminal VI.

[0007] More preferably, the end insulation is an insulating paperboard molded part or is made of multiple layers of insulating paperboard rolled together.

[0008] More preferably, the pressure plate and the support plate have the same structure, both being concentric rings with the iron core, made of laminated cardboard or laminated wood, and having lead-out holes I for each terminal block to facilitate the lead-out of each terminal block.

[0009] More preferably, the upper yoke insulation includes an insulating paper ring and a plurality of insulating pads uniformly bonded to the lower end of the insulating paper ring along its circumference; the insulating paper ring is a circular ring concentric with the iron core, and has lead-out holes II corresponding to lead-out holes I for each terminal, so as to facilitate the lead-out of each terminal.

[0010] More preferably, the lower yoke insulation includes an insulating paper ring and a plurality of insulating pads uniformly bonded to the upper and lower ends of the insulating paper ring along its circumference; the insulating paper ring is a circular ring concentric with the iron core, and has lead-out holes III corresponding to lead-out holes I for each terminal, so as to facilitate the lead-out of each terminal.

[0011] More preferably, the insulating end ring comprises two layers of insulating paper rings and an insulating pad uniformly bonded between the two layers of insulating paper rings along their circumference; the insulating paper rings are concentric rings with the iron core, and have annular holes concentric with the iron core. The annular holes correspond to the oil passages of the low-voltage winding and the lower low-voltage winding.

[0012] The beneficial effects of this invention are: using the high-impedance transformer of this invention can both increase the transformer impedance and reduce the temperature rise of the transformer windings. Applying this high-impedance transformer can simultaneously meet the operating conditions of both reactor and transformer modes. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the internal structure of the present invention; Figure 2 This is a top view of the pressure plate of this utility model; Figure 3 This is a top view of the pallet in this utility model; Figure 4 This is a front view of the upper yoke insulation in this utility model; Figure 5 This is a bottom view of the upper yoke insulation in this utility model; Figure 6 This is a front view of the insulating end ring in this utility model; Figure 7 This is a bottom view of the insulating end ring in this utility model; Figure 8 This is a front view of the lower yoke insulation in this utility model; Figure 9 This is a bottom view of the lower yoke insulation in this utility model; Figure 10 This is a schematic diagram of the cross-sectional structure of the grounding screen before it is rolled up in this utility model.

[0014] In the diagram: 1 is the iron core, 2 is the insulating cylinder, 3 is the support bar, 4, 5, 6, 7, 8 and 9 are all coils, 10 is the grounding shield, 11 is the oil channel, 12 is the end insulation, 131 is terminal I, 132 is terminal II, 133 is terminal III, 134 is terminal IV, 141 is terminal V, 142 is terminal VI, 15 is the pressure plate, 16 is the upper yoke insulation, 17 is the insulating end ring, 18 is the lower yoke insulation, 19 is the support plate, 20 is the lead-out hole I, 21 is the lead-out hole II, 22 is the insulating paper ring, 23 is the insulating pad, 24 is the annular hole, 25 is the copper plate, 26 is the multi-layer cable paper, 27 is the insulating paperboard, and 28 is the lead-out hole III. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0016] like Figures 1 to 10As shown, this embodiment includes an upper low-voltage winding and a lower low-voltage winding that are symmetrically arranged. The upper and lower low-voltage windings each include an insulating cylinder 2 fitted onto the iron core 1, support bars 3 evenly distributed outside the insulating cylinder 2, six coils concentrically wound with copper wire outside the support bars 3: coil 4, coil 5, coil 6, coil 7, coil 8, and coil 9, a grounding shield 10 positioned outside the outermost coil 9, oil channels 11 between two adjacent coils or between coil 9 and grounding shield 10, and end insulation 12 fixed to both ends of the coils and grounding shield 10. The end insulation 12 at the lower end of the upper low-voltage winding is positioned above the insulating end ring 17, and the end insulation 12 at the upper end of the lower low-voltage winding is positioned below the insulating end ring 17. An upper yoke insulation 16 is positioned above the end insulation 12 at the upper end of the upper low-voltage winding, and a pressure plate 15 is positioned above the upper yoke insulation 16. The lower yoke insulation 18 is placed below the end insulation 12 at the lower end of the lower low-voltage winding, and the support plate 19 is placed below the lower yoke insulation 18. The innermost coils 4 of the upper and lower low-voltage windings respectively extend upwards to terminal I 131 and downwards to terminal II 132, while the outermost coils respectively extend upwards to terminal III 133 and downwards to terminal IV 134. The grounding shields 10 of the upper and lower low-voltage windings respectively extend upwards to terminal V 141 and downwards to terminal VI 142. In this embodiment, terminals I 131, II 132, III 133, and IV 134 are the coil primary wires or copper busbars.

[0017] In this embodiment, the core column 1 is a single-phase, two-column core made of stacked silicon steel sheets. The insulating cylinder 2 is a molded insulating paper cylinder. The support bar 3 is made of laminated insulating paperboard.

[0018] In this embodiment, the oil channel 11 is provided with a rectangular support strip made of laminated insulating paperboard, or a support strip curtain made of a rectangular support strip made of laminated insulating paperboard bonded to cable paper, or a corrugated cardboard made of insulating paperboard pressed together.

[0019] In this embodiment, the grounding shield 10 is formed by rolling together an upper layer of multi-layer cable paper 26, a middle layer of copper plate 25, and a lower layer of insulating cardboard 27. Copper braided wire leads out to terminal V141 is welded to the upper end of the copper plate 25, or copper braided wire leads out to terminal VI142 is welded to the lower end of the copper plate 25. The end insulation 12 is an insulating cardboard molded part or is formed by rolling multiple layers of insulating cardboard.

[0020] In this embodiment, the pressure plate 15 and the support plate 19 have the same structure. They are both concentric rings with the iron core, made of laminated cardboard or laminated wood, and have lead-out holes I20 for each terminal to facilitate the lead-out of each terminal.

[0021] In this embodiment, the upper yoke insulation 16 includes an insulating paper ring 22 and a plurality of insulating pads 23 uniformly bonded to the lower end of the insulating paper ring 22 along the circumference of the insulating paper ring 22; the insulating paper ring 22 is a ring concentric with the iron core, and has lead-out holes II 21 on it corresponding to each terminal corresponding to the lead-out hole I 20, so as to facilitate the lead-out of each terminal.

[0022] In this embodiment, the lower yoke insulation 18 includes an insulating paper ring 22 and a plurality of insulating pads 23 uniformly bonded to the upper and lower ends of the insulating paper ring 22 along the circumference of the insulating paper ring 22; the insulating paper ring 22 is a ring concentric with the iron core, and has lead-out holes Ⅲ28 on it corresponding to each terminal corresponding to the lead-out hole Ⅰ20, so as to facilitate the lead-out of each terminal.

[0023] In this embodiment, the insulating end ring 17 includes two layers of insulating paper rings 22 and an insulating pad 23 uniformly bonded between the two layers of insulating paper rings 22 along the circumference of the insulating paper rings 22; the insulating paper rings 22 are circular rings concentric with the iron core, and have annular holes 24 concentric with the iron core. The annular holes 24 correspond to the oil passages 11 of the low-voltage winding and the lower low-voltage winding.

[0024] Of course, there are other embodiments of this utility model. Without departing from the spirit and essence of this utility model, those skilled in the art can make corresponding changes and modifications based on this utility model. However, these corresponding changes and modifications should all be considered improvements of equivalent technology and fall within the protection scope of the claims of this utility model.

Claims

1. A split low-voltage winding for a high-impedance transformer, characterized in that: It includes an upper low-voltage winding and a lower low-voltage winding that are symmetrically arranged. The upper low-voltage winding and the lower low-voltage winding each include an insulating cylinder (2) fitted on the iron core (1), a support bar (3) evenly distributed on the outside of the insulating cylinder (2), multiple coils concentrically wound outside the support bar (3), a grounding screen (10) set outside the outermost coil, an oil channel (11) set between two adjacent coils or between the coil and the grounding screen (10), and end insulation (12) tied and fixed at both ends of the coil and the grounding screen (10). The end insulation (12) at the lower end of the upper low-voltage winding is placed at the upper end of the insulating end ring (17), and the end insulation (12) at the upper end of the lower low-voltage winding is placed at the lower end of the insulating end ring (17). The upper yoke insulation (16) is placed on the upper low-voltage winding. The upper end of the end insulation (12) of the upper group is placed on the upper end of the upper yoke insulation (16); the lower yoke insulation (18) is placed on the lower end of the end insulation (12) of the lower low voltage winding, and the support plate (19) is placed on the lower end of the lower yoke insulation (18); the innermost coils of the upper low voltage winding and the lower low voltage winding are respectively led out to terminal I (131) and terminal II (132) along the axial direction, and the outermost coils of the two are respectively led out to terminal III (133) and terminal IV (134) along the axial direction, respectively; the grounding screen (10) of the upper low voltage winding and the lower low voltage winding are respectively led out to terminal V (141) and terminal VI (142) along the axial direction, respectively.

2. The split low-voltage winding for a high-impedance transformer according to claim 1, characterized in that: The oil passage (11) is provided with rectangular support strips made of laminated insulating paperboard, or with a support strip curtain made of rectangular support strips made of laminated insulating paperboard bonded to cable paper, or with corrugated paperboard made of insulating paperboard pressed together.

3. The split low-voltage winding for a high-impedance transformer according to claim 1 or 2, characterized in that: The grounding shield (10) is made of multiple layers of cable paper (26) stacked together, a copper plate (25) in the middle and an insulating cardboard (27) in the lower. The copper plate (25) has a copper braided wire lead-out terminal V (141) welded to the upper end or a copper braided wire lead-out terminal VI (142) welded to the lower end.

4. The split low-voltage winding for a high-impedance transformer according to claim 1 or 2, characterized in that: The upper yoke insulation (16) includes an insulating paper ring (22) and multiple insulating pads (23) uniformly bonded to the lower end of the insulating paper ring (22) along the circumference of the insulating paper ring (22); the insulating paper ring (22) is a circular ring concentric with the iron core, and has lead-out holes (21) of each terminal corresponding to lead-out hole I (20) on it.

5. The split low-voltage winding for a high-impedance transformer according to claim 1 or 2, characterized in that: The lower yoke insulation (18) includes an insulating paper ring (22) and multiple insulating pads (23) uniformly bonded to the upper and lower ends of the insulating paper ring (22) along the circumference of the insulating paper ring (22); the insulating paper ring (22) is a circular ring concentric with the iron core, and has lead-out holes (28) of each terminal corresponding to lead-out hole I (20) on it.

6. The split low-voltage winding for a high-impedance transformer according to claim 1 or 2, characterized in that: The insulating end ring (17) includes two layers of insulating paper rings (22) and an insulating pad (23) uniformly bonded between the two layers of insulating paper rings (22) along the circumference of the insulating paper rings (22); the insulating paper rings (22) are circular rings concentric with the iron core, and have annular holes (24) concentric with the iron core.

7. The split low-voltage winding for a high-impedance transformer according to claim 1 or 2, characterized in that: The end insulation (12) is an insulating paperboard molded part or is made of multiple layers of insulating paperboard rolled up.

8. The split low-voltage winding for a high-impedance transformer according to claim 1 or 2, characterized in that: The pressure plate (15) and the support plate (19) have the same structure. They are both concentric rings with the iron core, made of laminated cardboard or laminated wood, and have lead-out holes I (20) for each terminal block.

9. The split low-voltage winding for a high-impedance transformer according to claim 3, characterized in that: The upper yoke insulation (16) includes an insulating paper ring (22) and multiple insulating pads (23) uniformly bonded to the lower end of the insulating paper ring (22) along the circumference of the insulating paper ring (22); the insulating paper ring (22) is a circular ring concentric with the iron core, and has lead-out holes (21) of each terminal corresponding to lead-out hole I (20) on it.

10. The split low-voltage winding for a high-impedance transformer according to claim 9, characterized in that: The lower yoke insulation (18) includes an insulating paper ring (22) and multiple insulating pads (23) uniformly bonded to the upper and lower ends of the insulating paper ring (22) along the circumference of the insulating paper ring (22); the insulating paper ring (22) is a circular ring concentric with the iron core, and has lead-out holes (28) of each terminal corresponding to lead-out hole I (20) on it.

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