An ice-melting rectifier transformer with high overload resistance and harmonic suppression

Abstract

The application discloses a high-overload-resistance and harmonic-suppression ice-melting rectifier transformer, and relates to the technical field of transformers. The high-overload-resistance and harmonic-suppression ice-melting rectifier transformer comprises an oil tank, the iron core in the oil tank adopts a step-by-step stacking structure and a 45-degree full-inclined joint, and is fastened through a clamping piece module; three coil assemblies and a grounding electric shielding layer are arranged on a core column, the coil assembly comprises upper and lower windings, adopts a <2mm oxygen-free copper wire matched with a K transposition process, and a supporting block is arranged between adjacent wires to form an oil channel; the grounding electric shielding layer is composed of a copper foil shielding plate and a connecting plate and is grounded; and the oil tank forms a circulating heat dissipation system through an oil circuit, an oil pump and an air cooler. Through cooperation of multiple structures, the high-overload-resistance and harmonic-suppression ice-melting rectifier transformer reduces magnetic resistance and loss, improves structural stability, realizes efficient heat dissipation, suppresses harmonic pollution, enhances the anti-overload and anti-short-circuit capability, meets the demand of direct-current ice melting, and guarantees safe operation of a power grid in winter.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and specifically to a de-icing rectifier transformer with high overload resistance and harmonic suppression. Background Technology

[0002] Icing on transmission lines poses a significant threat to the safe operation of power grids in winter. Icing causes a surge in conductor weight and sag, easily leading to line breaks and tower collapses, resulting in widespread power outages. Currently, high-voltage main power grids widely employ DC de-icing technology. This technology involves applying DC voltage to iced lines and short-circuiting the ends, utilizing Joule heating to melt the ice, replacing traditional manual de-icing methods and significantly improving de-icing efficiency and safety.

[0003] As the core power conversion unit of the DC ice-melting system, the ice-melting rectifier transformer bears the crucial responsibility of converting AC power from the power grid into DC power that meets the requirements of ice-melting operations. Its structural stability and operational reliability directly determine the overall operational effectiveness of the DC ice-melting system and are of great significance to ensuring the safe and stable operation of the power grid in winter. With the continuous expansion of the power grid and the increasing demand for large-scale and high-reliability ice-melting operations, existing ice-melting rectifier transformers have gradually revealed significant technical shortcomings in practical applications. These include the inability of existing heat dissipation structures to quickly dissipate heat due to the need for short-term high current output during ice-melting operations, resulting in excessive temperature rise of winding hot spots and accelerated insulation aging. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high-overload-resistance, harmonic-suppression, ice-melting rectifier transformer, specifically achieved through the following technical solution:

[0005] A high-overload-resistance, harmonic-suppressing, de-icing rectifier transformer includes an oil tank. An iron core is installed inside the oil tank. From the outside to the inside, a grounding shield and three coil assemblies are sequentially installed on the core column of the iron core. Gaps are provided between the core column and the coil assemblies, between adjacent coil assemblies, and between the coil assemblies and the grounding shield. Each of the three coil assemblies includes an upper winding and a lower winding. An insulating pad is installed between the upper and lower windings. The upper and lower windings of the same coil assembly are electrically connected outside the oil tank. Support blocks are installed between adjacent turns of the upper and lower windings, forming radial oil channels between adjacent support blocks. The oil tank is connected to the inlet of an oil pump via a first oil passage. The outlet of the oil pump is connected to the inlet of an air cooler via a flange. The outlet of the air cooler is connected to the first end of a second oil passage via a flange. The second end of the second oil passage is connected to the oil tank via a flange.

[0006] The iron core is composed of laminated sheets arranged in a step-stack structure.

[0007] The iron core includes an upper yoke and a lower yoke, and three core posts are installed between the upper yoke and the lower yoke. The upper yoke, the lower yoke, and the core posts are fixed together by a clamping module.

[0008] The clamping module includes an upper clamp, a lower clamp, and a pull plate. The upper yoke is located inside the upper clamp, and the lower yoke is located inside the lower clamp. There are several pull plates, which are evenly distributed on both sides of the iron core. The first end of the pull plate is located between the upper clamp and the upper yoke and is fastened by a first pull rod. The second end of the pull plate is located between the lower clamp and the lower yoke and is fastened by a second pull rod.

[0009] The grounding shielding layer includes several ring-shaped shielding plates that are wound sequentially from top to bottom around the outermost coil assembly, with gaps between adjacent shielding plates; adjacent shielding plates are connected by a connecting plate, and one of the shielding plates is grounded.

[0010] Both the shielding plate and the connecting plate are made of copper foil.

[0011] Support bars are installed between the grounding shield layer and the coil assembly, between adjacent coil assemblies, and between the coil assembly and the iron core.

[0012] Both ends of the support block are provided with dovetail grooves, and the dovetail grooves are coupled with the corresponding support bars.

[0013] The core post is connected to the upper and lower yokes by a 45° fully oblique joint.

[0014] The coil assembly uses oxygen-free copper wire with a thickness of ≤2mm and is wound using the K transposition process.

[0015] The technical solution of this invention has the following advantages:

[0016] The ice-melting rectifier transformer with high overload resistance and harmonic suppression provided by this invention comprehensively solves the technical bottlenecks of existing ice-melting rectifier transformers in short-time high-current ice-melting operations, such as insufficient structural stability, low heat dissipation efficiency, serious harmonic pollution, and lack of overload and short-circuit resistance, through a synergistic technical solution of core structure optimization, innovative coil assembly design, grounding shielding layer setting, and efficient heat dissipation system construction. This improves the overall performance and operational reliability of the equipment.

[0017] The iron core adopts a stepped stacking structure and a 45° fully oblique joint design between the upper and lower yokes. Combined with upper and lower clamps and evenly distributed pull plates secured by tie rods, this clamping structure significantly reduces magnetic circuit reluctance and additional losses, reduces unit no-load losses, and improves core compactness, effectively suppressing vibration and noise. It also withstands short-term short-circuit electrodynamic forces, prevents winding deformation, and ensures structural stability. All three coil assemblies use a segmented electrical connection between the upper and lower windings with added insulating pads. The conductors are made of oxygen-free copper with a thickness ≤2mm and wound using a K-transposition process, which improves insulation strength, achieves balanced magnetic field distribution, reduces axial leakage flux, lowers eddy current losses and high-frequency harmonic losses, and enhances the equipment's short-circuit and overload resistance. The core column and wire... The gaps reserved between coil assemblies, between adjacent coil assemblies, and between coil assemblies and the grounding shielding layer, combined with the oil channels formed by the support blocks between adjacent conductors and the support bar structure with dovetail grooves at both ends for coupling, create a heat dissipation channel without dead angles. In addition, the oil tank, through the oil circuit, and the circulating heat dissipation system composed of the oil pump and air cooler, forms a highly efficient "oil-air" three-dimensional heat dissipation system, which can quickly dissipate the heat generated by short-term high-current operation, effectively reduce the temperature rise of winding hot spots, and delay insulation aging. The grounding shielding layer, which is composed of several annular copper foil shielding plates wound from top to bottom and connected by copper foil connecting plates and grounded, can efficiently absorb high-frequency harmonics and suppress electromagnetic oscillations. It works synergistically with the K transposition process to control the harmonic distortion rate of the power grid side at a low level, avoid harmonic pollution, and further reduce additional losses. The aforementioned technical features work together synergistically to comprehensively improve the equipment in terms of structural stability, overload resistance, harmonic suppression, and heat dissipation efficiency. This fully meets the needs of large-scale, high-reliability DC de-icing, effectively avoids accidents such as transmission line breaks and tower collapses caused by icing, and provides efficient and stable core power conversion guarantee for the safe and stable operation of the power grid in winter. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 This is a top view of the structure of the present invention;

[0021] Figure 3 This is a schematic diagram of the transformer structure;

[0022] Figure 4 This is a side view of the vessel's structure.

[0023] Figure 5 for Figure 4 Schematic diagram of the structure at point A;

[0024] Figure 6 for Figure 4 Schematic diagram of the structure at point B;

[0025] Figure 7 This is a schematic diagram of the iron core structure;

[0026] Figure 8 for Figure 7 Schematic diagram of the structure at point C;

[0027] Figure 9 This is a schematic diagram of the installation structure of the coil module;

[0028] Figure 10 A schematic diagram of the structure of the grounding shielding layer;

[0029] Figure 11 This is a schematic diagram of the installation structure of the third coil assembly;

[0030] Figure 12 This is a schematic diagram of the radial oil passage structure;

[0031] Figure 13 This is a schematic diagram of another device mounting structure according to the present invention.

[0032] In the diagram, 1-transformer, 2-oil outlet pipe, 3-first oil circuit, 4-oil pump, 5-air cooler, 6-second oil circuit, 7-oil inlet pipe, 8-trailer, 9-terminal, 10-oil tank, 11-upper clamp, 12-iron core, 1201-upper yoke, 1202-core post, 1203-lower yoke, 13-upper winding, 14-lower winding, 15-lower clamp, 16-oil tank cover, 17-base plate, 18-upper fastener, 19-... - Pull plate, 20- First side plate, 21- Support plate, 22- Second side plate, 23- Lower fastener, 24- Positioning stake, 25- Stacked plate, 26- First coil assembly, 27- Second coil assembly, 28- Third coil assembly, 29- Lead wire, 30- Shielding plate, 31- Connecting plate, 32- First support bar, 33- Support block, 34- Second support bar, 35- Wire, 36- Radial oil passage, 37- Vibration damper, 38- Ear plate. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the module or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] As attached Figure 1 Appendix Figure 2 and attached Figure 3 As shown, the present invention provides a high overload resistance and harmonic suppression de-icing rectifier transformer, including an air cooler 5 and a transformer 1 bolted to a trailer 8. The transformer 1 includes an oil tank 10, with an oil outlet pipe 2 fixedly installed on the upper part and an oil inlet pipe 7 fixedly installed on the lower part. The oil outlet pipe 2 is connected to the first end of the first oil circuit 3 through a flange, the second end of the first oil circuit 3 is connected to the oil inlet end of the oil pump 4 through a flange, the oil outlet end of the oil pump 4 is connected to the oil inlet of the air cooler 5 through a flange, the oil outlet of the air cooler 5 is connected to the first end of the second oil circuit 6 through a flange, and the second end of the second oil circuit 6 is connected to the oil inlet pipe 7 through a flange.

[0038] The tank body is detachably installed inside the oil tank 10.

[0039] The device body includes an iron core 12 and a clamping module; the structure of the iron core 12 is shown in the attached figure. Figure 7As shown, a three-phase, three-column structure is adopted, including an upper yoke 1201, a lower yoke 1203, and a core column 1202 installed between the upper yoke 1201 and the lower yoke 1203. The core column 1202 is designed to be circular to optimize the magnetic field distribution.

[0040] The core 12 is made of cold-rolled high-permeability grain-oriented silicon steel sheet with low hysteresis expansion as the lamination 25, and the magnetic flux density is controlled below 1.5T to reduce the unit no-load loss.

[0041] The core post 1202 is connected to the upper yoke 1201 and the lower yoke 1203 with a 45° oblique joint; the laminate 25 adopts a step stacking structure to reduce magnetic circuit resistance and additional losses; the iron core 12 is bundled with polyester tape by a pneumatic packing machine (binding tension ≥ 5kN), and with the full-enclosed ring clamping structure, the tightness of the iron core 12 is ensured and vibration noise is suppressed. That is, after the iron core 12 is stacked, it is bundled with polyester tape, and then heat shrink tubing is attached. After the heat shrink tubing is attached, it is heated so that the heat shrink tubing tightly wraps the iron core 12.

[0042] As attached Figure 7 and attached Figure 8 As shown, the step-stack structure reduces the magnetic reluctance abrupt change at the joint between the laminations 25, and the 45° fully oblique joint makes the magnetic flux transition more smoothly between the yoke and the core column, reducing hysteresis loss and eddy current loss.

[0043] The clamping module includes an upper clamping member 11, a lower clamping member 15, and a pull plate 19. The upper clamping member 11 is mounted on the upper yoke 1201, and the lower clamping member 15 is mounted on the lower yoke 1203. The upper clamping member 11 and the lower clamping member 15 are connected by the pull plate 19.

[0044] The structure of the upper clamp 11 is shown in the attached figure. Figure 5 As shown, the upper fastener 18 is fastened to the upper yoke 1201. A first side plate 20 is provided on both sides of the upper fastener 18. The first side plate 20 is fixed to the upper fastener 18 by a first pull rod. Specifically, the first pull rod passes through the two first side plates 20, the upper yoke 1201 and the upper fastener 18, and nuts are installed at both ends. Tightening the nuts at both ends will fasten the first side plate 20 to the upper fastener 18 together, thereby wrapping the upper yoke 1201 from three sides.

[0045] The structure of the lower clamp 15 is shown in the attached figure. Figure 6 As shown, it includes a lower fastener 23 that supports the lower yoke 1203 from the bottom. The lower fastener 23 has a second side plate 22 on both sides. The second side plate 22 is fixed to the lower fastener 23 by a second pull rod. Specifically, the second pull rod passes through the two second side plates 22, the lower yoke 1203 and the lower fastener 23, and is equipped with nuts at both ends. Tightening the nuts at both ends will fasten the second side plate 22 and the lower fastener 23 together, thereby wrapping the lower yoke 1203 from three sides.

[0046] Several pull plates 19 are evenly installed on both sides of the iron core 12. Specifically, the first end of the pull plate 19 is located between the first side plate 20 and the upper yoke 1201, and the second end of the pull plate 19 is located between the second side plate 22 and the lower yoke 1203.

[0047] The pull plate 19 is fastened to the first side plate 20 and to the second side plate 22 by pull rods, that is, the first pull rod and the second pull rod both pass through the pull plate 19.

[0048] The pull plate 19, together with the first side plate 20 and the second side plate 22, tightly presses the iron core 12 from the left and right sides and the top and bottom ends to maintain the stability of the iron core 12.

[0049] Polyester tape binding and heat shrink tubing wrapping form a fully enclosed annular clamping structure. Together with the clamping module, it applies uniform clamping force to the iron core 12 from multiple dimensions (top, bottom, left, and right), improving the compactness of the iron core 12. This structure not only suppresses the vibration of the iron core 12 but also resists the electrodynamic forces during short-term short circuits.

[0050] As attached Figure 6 As shown, a base plate 17 is fixedly installed on the bottom wall of the oil tank 10, and the lower clamp 15 is fixed to the base plate 17 by bolts. A positioning stake 24 is also fixedly installed on the bottom wall of the oil tank 10, and a positioning hole is opened on the lower clamp 15 to slide with the positioning stake 24. The presence of the positioning hole and the positioning stake 24 not only facilitates the installation of the device body, but also helps the bolts to maintain the stability of the device body.

[0051] Both the iron core 12 and the clamp module are coated with insulating, moisture-proof, and rust-proof resin paint, and the iron core 12 is grounded.

[0052] As attached Figure 3 Appendix Figure 9 and attached Figure 10 As shown, a coil module is mounted on the core post 1202. (See attached image.) Figure 6 As shown, a support plate 21 is fixedly installed on the second side plate 22 to support the coil module.

[0053] The outer side of the coil module is wrapped with a grounding shielding layer, which effectively absorbs high-frequency harmonics, suppresses electromagnetic oscillations, and controls the harmonic distortion rate (THD) on the grid side to below 3%.

[0054] The structure of the grounding shield is shown in the attached figure. Figure 10 It includes several ring-shaped shielding plates 30 that are wound sequentially from top to bottom around the outside of the coil module, with gaps between adjacent shielding plates 30; adjacent shielding plates 30 are connected by a connecting plate 31.

[0055] The shielding plate 30 and the connecting plate 31 are made of the same material, both using 0.1mm thick copper foil. One of the shielding plates 30 has a grounding lead 29 fixed on it.

[0056] As attached Figure 9 As shown, the coil module includes, from the outside in, a first coil assembly 26, a second coil assembly 27, and a third coil assembly 28. The first coil assembly 26 is a 35 kV coil, the second coil assembly 27 is a 10 kV coil, and the third coil assembly 28 is a 5.3 kV coil. This allows the input voltage of the invention to be adapted to multi-level power grids of 10-35 kV; the output voltage is 5.3 kV, meeting the de-icing voltage requirements of lines with different icing thicknesses.

[0057] The aforementioned grounding shielding layer is wrapped around the outside of the first coil assembly 26.

[0058] Gaps are provided between the first coil assembly 26 and the second coil assembly 27, between the second coil assembly 27 and the third coil assembly 28, between the third coil assembly 28 and the core post 1202, and between the grounding shield layer and the first coil assembly 26, serving as axial oil passages.

[0059] The conductors 35 of the first coil assembly 26, the second coil assembly 27, and the third coil assembly 28 are all made of ultra-thin oxygen-free copper conductors with a thickness of ≤2mm. Combined with the new K transposition process (transposition is completed every 8-10 turns), the magnetic field distribution is balanced, eddy current loss and high-frequency harmonic loss are reduced, and the load loss is reduced by more than 15%.

[0060] Oxygen-free copper wires have high conductivity and low resistance, and their ≤2mm ultra-thin design reduces the skin effect. The K transposition process balances the leakage magnetic field distribution and current density of each wire 35 by periodically changing the position of the wire 35, thereby reducing eddy current loss and high-frequency harmonic loss.

[0061] The K-transformation process balances the magnetic field distribution from the source, reducing harmonic generation; the grounding shielding layer utilizes the high conductivity of copper foil to absorb high-frequency harmonics generated by the coil and suppress electromagnetic oscillations through the dual effects of electrostatic and electromagnetic shielding.

[0062] The conductor 35 is wrapped in multiple layers of heat-modified paper with a temperature resistance rating of B, and then wound around after wrapping. (See attached diagram) Figure 12 As shown, radial oil channels 36 are provided between two adjacent turns of conductor 35. Heat-modified paper with a temperature resistance rating of B and insulating pads enhance electrical insulation strength, resisting the effects of high voltage and temperature rise in the windings.

[0063] Specifically, as shown in the attached document Figure 11 As shown, a support block 33 is installed between two adjacent coils of wire 35, and a radial oil passage 36 is formed between two adjacent support blocks 33.

[0064] As attached Figure 11As shown, dovetail grooves are provided at both ends of the support block 33, and the first support bar 32 and the second support bar 34 are coupled in the two dovetail grooves respectively. That is, at least a part of the first support bar 32 and the second support bar 34 are located in the corresponding dovetail grooves respectively.

[0065] The first support bar 32 in the first coil assembly 26 abuts against the outside of the second coil assembly 27, and the second support bar 34 abuts against the inside of the grounding shielding layer.

[0066] The first support bar 32 of the second coil assembly 27 abuts against the outside of the third coil assembly 28, and the second support bar 34 abuts against the inside of the first coil assembly 26.

[0067] The first support bar 32 in the third coil assembly 28 abuts against the outside of the core post 1202, and the second support bar 34 abuts against the inside of the second coil assembly 27.

[0068] Of course, in actual use, the first support bar 32 in the first coil assembly 26 and the second support bar 34 in the second coil assembly 27 can be the same component; similarly, the first support bar 32 in the second coil assembly 27 and the second support bar 34 in the third coil assembly 28 can be the same component. This way, the normal functions of the first support bar 32 and the second support bar 34 are retained, costs are saved, and the structural stability is further maintained.

[0069] The presence of the first support bar 32 and the second support bar 34 not only maintains the structural stability of the coil module but also forms axial oil channels inside the coil module, allowing the iron core 12, wire 35, and grounding shielding layer to be fully immersed in the cooling oil. This design effectively avoids heat dissipation dead zones, eliminates winding hot spots, and reduces hot spot temperature rise by 6%-7%.

[0070] As attached Figure 3 and attached Figure 4 As shown, the first coil assembly 26, the second coil assembly 27, and the third coil assembly 28 all include an upper winding 13 and a lower winding 14 that are electrically connected to each other. Specifically, six terminals 9 are fixedly installed on the oil tank cover 16 at the top of the oil tank 10, of which three terminals 9 are electrically connected to the three upper windings 13, and the other three terminals 9 are electrically connected to the lower windings 14. Two terminals 9 that are electrically connected to the upper windings 13 and the lower windings 14 of the same coil assembly are electrically connected to each other. This segmented continuous structure can combine low loss, high short-circuit immunity, and harmonic suppression characteristics.

[0071] An insulating pad is installed between the upper winding 13 and the lower winding 14 to improve insulation strength. The segmented structure ensures that the magnetomotive force is evenly distributed along the height direction, reducing axial leakage flux by 20% and improving short-circuit withstand capability.

[0072] As attached Figure 13As shown, the present invention also provides a connection method between the vessel body and the oil tank 10. In this connection method, in addition to the bolt connection between the lower clamp 15 and the base plate 17, ear plates 38 are installed on both the first side plate 20 and the second side plate 22. A shock absorber 37 is installed between the ear plate 38 and the inner wall of the oil tank 10, which can effectively absorb the impact force of transportation bumps. The bottom of the oil tank 10 is provided with a detachable rolling support, such as rollers or casters, which facilitates on-site relocation and eliminates the need for a lifting core installation, thus improving installation efficiency by 50%.

[0073] This invention achieves a THD of ≤3% on the power grid side through the synergistic effect of the grounding shielding layer and the K transposition process, thereby avoiding harmonic pollution and reducing additional losses.

[0074] The cooling oil in the oil tank 10 is cooled outside the oil tank 10 through the air cooler 5, forming a three-dimensional "oil-air" cooling system. During a short circuit, the temperature rise of the winding hot spot is ≤80K under three times the rated current.

[0075] The coil module has a built-in platinum resistance temperature sensor (accuracy ±0.5℃). The platinum resistance temperature sensor is electrically connected to the controller, and the controller is electrically connected to the air cooler 5 and the oil pump 4.

[0076] Real-time monitoring of hotspot temperatures; automatic activation of air-cooling power when temperatures exceed limits to ensure timely heat dissipation response.

[0077] The ice-melting rectifier transformer with high overload resistance and harmonic suppression provided by this invention comprehensively solves key technical bottlenecks such as insufficient structural stability and transportability, high loss and noise, and harmonic pollution of existing ice-melting rectifier transformers through synergistic innovation of multi-dimensional technical features. It improves the overall performance and reliability of the equipment, can fully meet the needs of large-scale and high-reliability DC ice melting, and provides an efficient and stable core power conversion solution for winter icing prevention of power grids. It effectively avoids accidents such as line breaks and pole collapses caused by icing and ensures the safe operation of the power grid.

[0078] In terms of structural stability, the iron core 12 adopts a three-phase, three-column structure. The circular core column 1202 optimizes the magnetic field distribution. Cold-rolled, high-permeability, grain-oriented silicon steel sheets with low hysteresis are selected as the laminations 25, controlling the magnetic flux density below 1.5T. Combined with a 45° fully oblique joint and a step-over lamination structure, the magnetic circuit reluctance and additional losses are significantly reduced, lowering the unit no-load loss. Simultaneously, the iron core 12 is bundled with polyester tape using a pneumatic strapping machine at a binding tension of no less than 5kN, and then tightly wrapped with heat-shrink tubing to form a fully enclosed annular clamping structure. This, combined with the upper clamp 11, lower clamp 15, and evenly distributed clamps on both sides of the iron core 12, further enhances the magnetic field stability. Pull plate 19, with its two ends respectively placed between the first side plate 20 and the upper yoke 1201, and between the second side plate 22 and the lower yoke 1203, and fastened by pull rods, tightly squeezes the iron core 12 from the left and right sides and the top and bottom ends, improving the compactness of the iron core 12 and effectively suppressing vibration noise; the lower clamp 15 is fixed to the bottom plate 17 of the bottom wall of the oil tank 10 by bolts, and slides with the positioning hole of the lower clamp 15 by means of the positioning stake 24, which simplifies the installation process of the device body, and also helps the bolts to enhance the stability of the device body, effectively resisting short-term short-circuit electrodynamics, avoiding winding deformation, and completely solving the problem of loose device body structure in the prior art.

[0079] In terms of ease of transportation and installation, the ear plates 38 installed on the first side plate 20 and the second side plate 22 and the shock absorber 37 between them and the inner wall of the oil tank 10 can effectively absorb the impact of bumps during transportation and prevent parts from loosening. The detachable rolling support set at the bottom of the oil tank 10 can be moved on site without the need for a lifting core, which improves the installation efficiency by 50% and solves the pain points of inconvenient transportation and complicated on-site installation and commissioning caused by the existing independent design of multiple body.

[0080] In terms of loss control and heat dissipation performance, the coil module on the core column 1202 adopts a layered structure of first coil assembly 26, second coil assembly 27, and third coil assembly 28 from the outside to the inside. Axial oil channels are reserved between each coil assembly, between the coil assembly and the core column 1202, and between the coil assembly and the grounding shielding layer. At the same time, a radial oil channel 36 is formed between two adjacent coils of wire 35 through a support block 33 with a dovetail groove, in conjunction with the first support bar 32 and the second support bar 34. The first support bar 32 and the second support bar 34 not only ensure the structural stability of the coil module, but also ensure that the iron core 12, wires 35, and grounding shielding layer are fully immersed in the heat dissipation oil, avoiding heat dissipation dead zones. The heat dissipation oil forms a high-efficiency system through the oil outlet pipe 2, the first oil passage 3, the oil pump 4, the air cooler 5, the second oil passage 6, and the oil inlet pipe 7. The "oil-air" three-dimensional heat dissipation circuit, combined with the platinum resistance temperature sensor with an accuracy of ±0.5℃ built into the coil module, monitors the hot spot temperature in real time. When the temperature exceeds the limit, it automatically triggers the air cooler 5 to increase its power, ensuring timely heat dissipation response and achieving a winding hot spot temperature rise of ≤80K under three times the rated current for a short period. The conductor 35 uses ultra-thin oxygen-free copper conductor with a thickness of ≤2mm, combined with a new K transposition process that completes transposition every 8-10 turns, which balances the magnetic field distribution and significantly reduces eddy current loss and high-frequency harmonic loss, reducing load loss by more than 15%. The upper winding 13 and lower winding 14 form a segmented continuous structure, combined with the insulating pads between them, which not only improves the insulation strength but also makes the magnetomotive force evenly distributed along the height direction, reducing axial leakage flux by 20% and enhancing the equipment's short-circuit resistance.

[0081] In terms of harmonic suppression and noise control, the grounding shielding layer wound around the outside of the first coil assembly 26 is composed of several 0.1mm thick copper foil shielding plates 30 in a ring shape with reserved gaps, connected by a connecting plate 31 and grounded through lead wire 29. It can effectively absorb high-frequency harmonics and suppress electromagnetic oscillations. Combined with the synergistic effect of the K transposition process, the harmonic distortion rate (THD) on the power grid side is controlled below 3%, avoiding harmonic pollution and further reducing additional losses. The iron core 12 and the clamping module are both sprayed with insulating, moisture-proof and rust-proof resin paint, and the iron core 12 is grounded, which not only improves the environmental resistance of the equipment, but also enhances electromagnetic stability and effectively reduces the impact of vibration and noise on the surrounding environment of the mountainous area.

[0082] This invention organically integrates various technical features, such as the structural optimization of the iron core 12, the design of the fastening and heat dissipation system, the innovation of the coil module, and the setting of the grounding shielding layer, to comprehensively improve the structural stability, transportation and installation convenience, overload resistance, harmonic suppression effect and heat dissipation efficiency of the ice-melting rectifier transformer, reduce operating losses and noise, and completely solve many defects of the existing technology, providing a reliable guarantee for the stable and efficient operation of the DC ice-melting system.

[0083] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A high-overload harmonic suppression ice-melting rectifier transformer, characterized in that, The system includes an oil tank (10), inside which is installed an iron core (12). A grounding shield and three coil assemblies are sequentially installed on the core post (1202) of the iron core (12) from the outside in. Gaps are left between the core post (1202) and the coil assemblies, between adjacent coil assemblies, and between the coil assemblies and the grounding shield. Each of the three coil assemblies includes an upper winding (13) and a lower winding (14). An insulating pad is installed between the upper winding (13) and the lower winding (14). The upper winding (13) and the lower winding (14) of the same coil assembly... 4) External electrical connection to the oil tank (10); a support block (33) is installed between two adjacent turns of wire (35) in the upper winding (13) and the lower winding (14), and a radial oil passage (36) is formed between two adjacent support blocks (33); the oil tank (10) is connected to the oil inlet of the oil pump (4) through the first oil passage (3), the oil outlet of the oil pump (4) is connected to the oil inlet of the air cooler (5) through a flange, the oil outlet of the air cooler (5) is connected to the first end of the second oil passage (6) through a flange, and the second end of the second oil passage (6) is connected to the oil tank (10) through a flange; The grounding shielding layer includes several ring-shaped shielding plates (30) that are wound sequentially from top to bottom around the outermost coil assembly. There is a gap between two adjacent shielding plates (30). Two adjacent shielding plates (30) are connected by a connecting plate (31), and one of the shielding plates (30) is grounded.

2. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 1, characterized in that, The iron core (12) is composed of laminations (25) arranged in a step-stack structure.

3. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 1, characterized in that, The iron core (12) includes an upper yoke (1201) and a lower yoke (1203), and three core posts (1202) are installed between the upper yoke (1201) and the lower yoke (1203). The upper yoke (1201), the lower yoke (1203) and the core posts (1202) are fixed together by a clamping module.

4. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 3, characterized in that, The clamping module includes an upper clamp (11), a lower clamp (15), and a pull plate (19). The upper yoke (1201) is located inside the upper clamp (11), and the lower yoke (1203) is located inside the lower clamp (15). There are several pull plates (19), which are evenly distributed on both sides of the iron core (12). The first end of the pull plate (19) is located between the upper clamp (11) and the upper yoke (1201) and is fastened by a first pull rod. The second end of the pull plate (19) is located between the lower clamp (15) and the lower yoke (1203) and is fastened by a second pull rod.

5. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 1, characterized in that, Both the shielding plate (30) and the connecting plate (31) are copper foil.

6. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 1, characterized in that, Support bars are installed between the grounding shield layer and the coil assembly, between adjacent coil assemblies, and between the coil assembly and the iron core (12).

7. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 6, characterized in that, Both ends of the support block (33) are provided with dovetail grooves, and the dovetail grooves are coupled with the corresponding support bars.

8. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 3, characterized in that, The core post (1202) is connected to the upper yoke (1201) and the lower yoke (1203) by a 45° oblique joint.

9. The ice-melting rectifier transformer with high overload resistance and harmonic suppression according to claim 1, characterized in that, The wires (35) of the coil assembly are all made of oxygen-free copper wire with a thickness of ≤2mm and are wound using the K transposition process.

Images