High-impedance autotransformer

Abstract

The high-impedance autotransformer comprises an iron core, a series winding, a common winding I and a common winding II, the common winding I and the common winding II are distributed in the axial direction of the iron core and located on different sections of the iron core, and the series winding, the common winding I and the common winding II are sequentially connected to the iron core in a sleeved mode. The coil supporting block is arranged between the windings and is fastened with the iron core; the supporting cushion blocks are arranged on winding end faces at the two ends of the transformer, and the coil supporting blocks and the supporting cushion blocks are made of insulating materials. The self-coupling transformer solves the technical problems that the self-coupling transformer in the prior art is low in short-circuit impedance and easy to damage during short-circuit impact.

Description

Technical Field

[0001] This application belongs to the field of transformer installation technology, and particularly relates to a high-impedance autotransformer. Background Technology

[0002] In the field of power transmission, autotransformers are a common transformer structure. Their design features a common winding and series windings concentrically mounted on a core column and arranged radially, with the low-voltage winding and high-voltage winding (or low-voltage, medium-voltage, and high-voltage windings) arranged from the inside out. This design effectively utilizes materials and achieves a compact structural layout, thus finding wide application in many situations.

[0003] However, existing reactor structures have certain limitations. First, existing reactors are typically quite tall with a relatively small leakage magnetic area, which negatively impacts their performance during short-circuit surges. Furthermore, the structural capacity of autotransformers is usually much smaller than their transmission capacity, resulting in relatively low short-circuit impedance, typically only around 1%. This low short-circuit impedance means that autotransformers must withstand larger short-circuit currents during short-circuit surges, increasing the risk of equipment failure and potential damage.

[0004] Therefore, existing reactors exhibit significant limitations when facing short-circuit impacts, which has become a pressing issue. Improving reactor structure to enhance its short-circuit impact withstand capability is an important research direction in this field. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides a high-impedance autotransformer, solving the technical problems of low short-circuit impedance and easy damage of existing autotransformers under short-circuit impact.

[0006] In one possible implementation, a high-impedance autotransformer is provided, comprising: an iron core, series windings, a common winding I, and a common winding II. The series windings, common winding I, and common winding II are mounted on the iron core, distributed along the axial direction of the iron core and located on different sections of the iron core. The series windings, common winding I, and common winding II are sequentially connected to the iron core. A coil support block, T-shaped, is disposed between the series windings, common winding I, and common winding II. Its horizontal side is a rectangular mounting portion, securely mounted to the iron core, and its vertical side is a spacer portion mounted on the mounting portion. The common winding I, common winding II, and series winding are engaged with the mounting portion mounted on the iron core. The spacer portion is positioned between the series winding and common winding I, and between common winding I and common winding II. Support pads are disposed on the end faces of the series winding and common winding II at both ends of the transformer. The coil support block and the support pads are made of insulating material.

[0007] In one possible implementation, three iron cores are provided, arranged vertically side by side.

[0008] In one possible implementation, it further includes: a terminal block disposed at the top of the three iron cores, wherein the terminal block is provided with pins that connect to the input and output terminals of the series winding, common winding I and common winding II.

[0009] In one possible implementation, the core is made of stacked low-loss silicon steel sheets.

[0010] In one possible implementation, the common winding I, the common winding II, and the series winding are all made of copper wire.

[0011] In one possible implementation, the series winding is a high-voltage winding.

[0012] In one possible implementation, common winding I and common winding II are low-voltage windings.

[0013] In one possible implementation, the three vertical iron cores are simultaneously fixedly connected to the upper and lower iron cores at both ends by clamps.

[0014] Based on the above technical solution, the high-impedance autotransformer of this invention, by axially distributing the series windings and the common winding, changes the direction of the main leakage flux from longitudinal to transverse, thereby increasing the equivalent leakage flux area and reducing the winding reactance height. This significantly improves the short-circuit impedance within the same volume, resulting in a smaller short-circuit inrush current. Furthermore, due to the axial winding distribution, the height of a single winding is smaller, leading to higher heat dissipation efficiency. This invention also enhances short-circuit resistance by incorporating upper and lower support pads, making the short-circuit impact force axial, further improving the transformer's safety and reliability. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0016] Figure 1 This is a schematic diagram of the structure of a high-impedance autotransformer according to one embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the structure of the high-impedance autotransformer decomposition coil support block according to one embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the leakage magnetic width W and reactance height h of a high-impedance autotransformer according to one embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the equivalent magnetic field distribution of a high-impedance autotransformer according to one embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the magnetic field distribution of a high-impedance autotransformer with coaxial radial windings of high and low voltage windings in the prior art.

[0021] In the picture:

[0022] 1. Series winding; 2. Common winding I; 3. Common winding II; 4. Iron core; 5. Terminal block; 6. Clamp; 7. Coil support block; 8. Support pad. Detailed Implementation

[0023] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0024] In the description of this application, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device 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 this application.

[0025] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] To address the technical problem of low short-circuit impedance and easy damage of existing autotransformers under short-circuit impact, this application proposes a high-impedance autotransformer.

[0028] See Figure 1 and Figure 2 In one possible implementation, the high-impedance autotransformer includes a core 4, a series winding 1, a common winding I2 and a common winding II3, a coil support block 7, and a support pad 8. The series winding 1, common winding I2, and common winding II3 are all mounted on the core 4 and distributed along the axial direction of the core 4, located in different sections of the core 4. The series winding 1, common winding I2, and common winding II3 are sequentially connected to the core 4. The coil support block 7 is disposed between the series winding 1, common winding I2, and common winding II3 to fix and isolate these windings. The coil support block 7 has a T-shaped structure, with one horizontal side being a rectangular mounting portion 71, which is fastened to the core 4, and the vertical side being a spacer portion 72. The mounting portion 71 is used to fix the connection between the windings and the core 4, while the spacer portion 72 is placed between the series winding 1 and the common winding I2, and between the common winding I2 and the common winding II3, to isolate and support the windings. Support pads 8 are located at both ends of the transformer, on the end faces of the series winding 1 and the common winding II 3, to further support and protect the windings. These coil support blocks 7 and support pads 8 are both made of insulating material to ensure the electrical insulation performance of the transformer.

[0029] In the above scheme, the high-impedance autotransformer achieves voltage regulation by connecting a series winding 1, a common winding I2, and a common winding II3 onto the iron core 4. By axially distributing the series windings with the common windings I2 and II3, the previous layout of coaxial inner and outer layers of windings is changed. The leakage magnetic field distribution is described in [reference needed]. Figure 5 This changes the direction of the main leakage flux from longitudinal to transverse. See [link / reference] Figure 4 This increases the equivalent leakage magnetic area, i.e., the leakage magnetic width W, and reduces the winding reactance height h. See [reference needed]. Figure 3 It can significantly improve short-circuit impedance within the same volume, resulting in a smaller short-circuit inrush current. In addition, due to the axial distribution of the windings, the height of a single winding is smaller, resulting in higher heat dissipation efficiency.

[0030] Coil support block 7 and support pad block 8 ensure the secure mounting and electrical insulation of the windings, while also separating the windings to reduce electromagnetic interference. The iron core 4 provides the necessary magnetic flux path for efficient power transfer. By optimizing the winding spacing and core structure, this design improves the transformer's impedance characteristics, making it suitable for applications in high-voltage power systems.

[0031] The transformer features a compact design, with robust and reliable fixing between the windings and the core, ensuring electrical insulation performance and enhancing its electromagnetic interference resistance. The use of T-shaped coil support blocks 7 further stabilizes the spacing between the windings, effectively preventing mechanical stress damage. Furthermore, the use of insulating support blocks and spacers further improves the transformer's safety and reliability.

[0032] In one possible implementation, three iron cores 4 are provided, arranged vertically side by side, to further enhance the magnetic flux density and overall rigidity of the transformer.

[0033] By arranging three vertically parallel iron cores 4, the magnetic flux path of the transformer can be increased, thereby improving the transformer's magnetic flux density and power transmission capacity. Simultaneously, the parallel arrangement of the three iron cores 4 enhances the overall mechanical rigidity of the transformer, reduces mechanical vibration and noise, and contributes to improving the transformer's stability and reliability.

[0034] In one possible implementation, the high-impedance autotransformer includes a terminal block 5 disposed at the top of three iron cores, the terminal block 5 having pins connected to the input and output terminals of the series winding 1, the common winding I2 and the common winding II3.

[0035] Terminal block 5 provides a centralized connection point, facilitating the connection of cables to the various windings of the transformer. By arranging the input and output pins on terminal block 5, wiring complexity is effectively reduced, and wiring reliability and safety are improved. Furthermore, the terminal block design also makes transformer maintenance and repair more convenient.

[0036] In one possible implementation, the core 4 of the high-impedance autotransformer is made of stacked low-loss silicon steel sheets.

[0037] Core 4 is constructed from stacked low-loss silicon steel sheets, designed to reduce hysteresis and eddy current losses. The low-loss characteristics of silicon steel sheets help improve the overall efficiency of the transformer and reduce energy loss in the core under alternating magnetic fields. Simultaneously, the stacked silicon steel sheet design effectively reduces eddy current generation in the core, further lowering losses.

[0038] In other implementations, different types of low-loss materials, such as amorphous alloys or nanocrystalline materials, can be selected to manufacture the core to further reduce losses and improve transformer performance. Furthermore, the thickness and stacking method of the silicon steel sheets can be adjusted according to specific application requirements to optimize the transformer's magnetic properties and mechanical strength.

[0039] In one possible implementation, the common winding I2, common winding II3, and series winding 1 of the high-impedance autotransformer are all made of copper wire.

[0040] Using copper wire as the winding material, its excellent conductivity and mechanical strength ensure low loss and high efficiency when transmitting high currents. Copper wire has high electrical conductivity, which allows the winding to transmit more current with a smaller cross-sectional area, thereby improving the overall efficiency of the transformer.

[0041] In one possible implementation, the series winding 1 in the high-impedance autotransformer is a high-voltage winding.

[0042] Series winding 1, as a high-voltage winding, is mainly used to withstand and transmit high voltage in high-voltage power systems. Because this winding needs to handle high voltages, special attention is paid to its electrical insulation performance and withstand voltage capability during design. The structure and material selection of series winding 1 have been optimized to ensure reliability and safety under high-voltage conditions.

[0043] Designing series winding 1 as a high-voltage winding enables the transformer to meet the demands of high-voltage power systems and provide stable power transmission. The high-voltage winding design improves the transformer's withstand voltage level, reduces the risk of corona discharge and breakdown, thereby enhancing equipment safety and service life.

[0044] In one possible implementation, the common winding I2 and common winding II3 in the high-impedance autotransformer are low-voltage windings.

[0045] Common winding I2 and common winding II3, as low-voltage windings, are primarily responsible for voltage distribution and regulation in low-voltage power systems. Because these windings are used in the low-voltage section, their electrical insulation and withstand voltage requirements are relatively low, allowing for a more economical design. Separating the low-voltage and high-voltage windings helps improve the transformer's safety and operating efficiency.

[0046] In one possible implementation, the two ends of the three vertical iron cores 4 are simultaneously fixedly connected to the upper and lower iron cores via clamps 6. This design ensures the stability and mechanical strength of the entire iron core structure. By firmly fixing the two ends of the vertical iron cores 4 between the upper and lower iron cores via clamps 6, mechanical vibration during transformer operation can be effectively reduced, and iron core loosening can be prevented, thereby improving the operational stability and reliability of the transformer.

[0047] The high-impedance autotransformer of this invention has the following advantages:

[0048] 1. Due to the axial distribution of the series winding and the common winding, the direction of the main leakage flux is changed from the longitudinal leakage flux of the existing technology to the transverse leakage flux, which can obtain a larger equivalent leakage flux area and reduce the winding reactance height. Under the same volume, a higher short-circuit impedance can be provided (5 to 40 times higher than the impedance of the existing solution), and the larger short-circuit impedance will result in a smaller short-circuit inrush current.

[0049] 2. The windings are axially distributed, resulting in a smaller individual winding height and higher heat dissipation efficiency.

[0050] 3. The short-circuit impact force is axial, and the support pads on both the top and bottom of the winding effectively increase short-circuit resistance. Existing technology uses radial impact force for short circuits, and there is no fixed support structure on the outside of the coil, which cannot enhance short-circuit resistance. Compared to existing technologies that rely solely on the strength of the coil's aluminum or copper wires to withstand short-circuit forces, this invention offers significantly stronger short-circuit resistance.

[0051] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0052] The above embodiments are only used to illustrate the technical solutions of this application and not to limit them; although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this application or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in this application.

Claims

1. A high-impedance autotransformer, characterized in that, include: Iron core (4); A series winding (1) is fitted onto the iron core (4); Common winding I (2) and common winding II (3) are mounted on the iron core (4), distributed along the axial direction of the iron core (4) and located in different sections of the iron core (4); The series winding (1), common winding I (2) and common winding II (3) are sequentially connected to the iron core (4); A coil support block (7) is set between the series winding (1), the common winding I (2) and the common winding II (3); the coil support block (7) is T-shaped, with one horizontal side being a rectangular mounting part (71) that is fastened to the iron core (4), and the vertical side being a spacer part (72) mounted on the mounting part (71); the common winding I (2), the common winding II (3) and the series winding (1) are engaged with the mounting part (71) mounted on the iron core (4); the spacer part (72) is placed between the series winding (1) and the common winding I (2), and between the common winding I (2) and the common winding II (3); Support pads (8) are provided on the end faces of the series windings (1) and common windings II (3) at both ends of the transformer; Among them, the coil support block (7) and the support pad block (8) are insulating materials.

2. The high-impedance autotransformer according to claim 1, characterized in that, Three iron cores (4) are set up, and the three iron cores (4) are arranged vertically side by side.

3. The high-impedance autotransformer according to claim 2, characterized in that, Also includes: Terminal block (5) is set at the top of the three iron cores. The terminal block (5) is provided with pins that connect to the input and output terminals of the series winding (1), common winding I (2) and common winding II (3).

4. The high-impedance autotransformer according to claim 2, characterized in that, in, The iron core (4) is made of stacked low-loss silicon steel sheets.

5. The high-impedance autotransformer according to claim 3, characterized in that, in, Common winding I (2), common winding II (3) and series winding (1) are all made of copper wire.

6. The high-impedance autotransformer according to claim 1, characterized in that, in, The series winding (1) is a high-voltage winding.

7. The high-impedance autotransformer according to claim 5, characterized in that, in, Common winding I (2) and common winding II (3) are low-voltage windings.

8. The high-impedance autotransformer according to claim 2, characterized in that, in, The three vertical iron cores are fixedly connected at both ends to the upper iron core and the lower iron core through clamps (6).

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