High-capacity ultrahigh-voltage transformer with on-load voltage regulation of high voltage and medium voltage

Abstract

The utility model discloses a high-capacity ultrahigh-voltage transformer with on-load voltage regulation for both high voltage and medium voltage. An iron core, a low-voltage winding, a medium-voltage winding, a high-voltage winding, a high-voltage regulating winding and a medium-voltage regulating winding are sequentially arranged from inside to outside; the high-voltage winding is connected with the high-voltage regulating winding through the high-voltage on-load switch; the medium-voltage winding is connected with the medium-voltage regulating winding through the medium-voltage on-load switch; the high-voltage regulating winding comprises an upper high-voltage regulating winding and a lower high-voltage regulating winding which are connected in parallel; and the medium-voltage regulating winding comprises an upper medium-voltage regulating winding and a lower medium-voltage regulating winding which are connected in parallel. The transformer has the function of adjusting two different voltage grades.

Description

Technical Field

[0001] This utility model belongs to the field of power transformer technology, specifically relating to a large-capacity ultra-high voltage transformer with on-load voltage regulation in both high-voltage and medium-voltage sections. Background Technology

[0002] With the accelerated transformation of the energy structure and the construction of new power systems, ultra-high voltage (EHV) (330-800kV) and extra-high voltage (UHV) (AC 1000 kV and above and DC +800 kV and above) transmission networks have become the core carriers for cross-regional energy allocation. The exponential growth in power grid scale has brought about structural changes: in power grids where the penetration rate of new energy sources has exceeded 35%, the daily power fluctuation of photovoltaic / wind power can reach 70% of the rated value, resulting in voltage fluctuations of ±15% at the receiving end bus. This places a rigid demand on the dynamic voltage regulation of the main transformer, which serves as the "voltage hub" of the power grid.

[0003] Large-capacity (200 MVA and above) ultra-high voltage power transformers typically employ on-load tap changer or off-load tap changer to adjust the transformer's output voltage.

[0004] In the above technical solutions, the transformer output voltage range is relatively narrow, which cannot meet the requirements of complex power grids or special loads. electricity Pressure stability Therefore, how to set and implement outputs with different voltage level adjustment ranges is a technical problem that needs to be solved in this field. Summary of the Invention

[0005] This utility model provides a large-capacity ultra-high voltage transformer with on-load tap changer in both high-voltage and medium-voltage sections. By providing on-load tap changer in both high-voltage and medium-voltage sections, the transformer connected to the power grid of different voltage levels can achieve the function of regulating two different voltage levels.

[0006] To achieve the above objectives, the present invention provides a large-capacity ultra-high voltage transformer with on-load tap changing for both high and medium voltages, comprising, from the inside out, an iron core, a low-voltage winding, a medium-voltage winding, a high-voltage winding, a high-voltage tap changing winding, and a medium-voltage tap changing winding; the high-voltage winding is connected to the high-voltage tap changing winding via a high-voltage on-load switch; the medium-voltage winding is connected to the medium-voltage tap changing winding via a medium-voltage on-load switch.

[0007] The high-voltage regulating winding includes an upper high-voltage regulating winding and a lower high-voltage regulating winding connected in parallel.

[0008] The medium-voltage regulating winding includes an upper medium-voltage regulating winding and a lower medium-voltage regulating winding connected in parallel.

[0009] A further improvement of this utility model is that an electrostatic plate is provided at the first end of the high-voltage winding.

[0010] A further improvement of this utility model is that the voltage regulation range of both the high-voltage on-load switch and the medium-voltage on-load switch is 8×1.25%.

[0011] A further improvement of this utility model is that the high-voltage regulating winding is a double-helix winding.

[0012] A further improvement of this utility model is that the medium-voltage regulating winding is a continuous winding.

[0013] A further improvement of this utility model is that the high-voltage on-load switch and the medium-voltage on-load switch are arranged on the same side of the iron core.

[0014] A further improvement of this utility model is that the high-voltage winding adopts a center-outlet configuration.

[0015] A further improvement of this utility model is that the medium-voltage winding adopts end-out wires.

[0016] A further improvement of this utility model is that the lead wire of the upper high voltage regulating winding is led out from the upper part of the upper medium voltage regulating winding, and the lead wire of the lower high voltage regulating winding is led out from the lower part of the lower medium voltage regulating winding.

[0017] A further improvement of this utility model is that the high-voltage regulating and medium-voltage regulating windings adopt a radial concentric structure.

[0018] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0019] The large-capacity ultra-high voltage on-load tap-changing transformer provided by this utility model achieves voltage adjustment on the high-voltage side by setting a high-voltage on-load tap-changing winding and a high-voltage on-load tap-changing switch on the high-voltage side, and achieves voltage adjustment on the medium-voltage side by setting a medium-voltage on-load tap-changing winding and a medium-voltage on-load tap-changing switch on the medium-voltage side. It can adapt to the fluctuations of the high-voltage and medium-voltage power grids respectively, so that a single transformer can be connected to power grids of different voltage levels to achieve two different voltage regulation functions, thereby significantly reducing the user's capital investment.

[0020] Furthermore, an electrostatic plate is installed at the lead-out point of the high-voltage winding, which can effectively improve the electric field distribution characteristics. The electrostatic plate reduces the axial and radial electric field gradients at the conductor ends through its voltage equalization effect, thereby suppressing partial discharge and dielectric loss. This structure avoids accelerated aging of the insulation material under high electric field strength, improves the long-term reliability of the winding insulation system, reduces the risk of local overheating, and enhances the transformer's withstand capability under overvoltage conditions.

[0021] Furthermore, the high-voltage on-load switch and the medium-voltage on-load switch are located on the same side of the iron core, which simplifies the complexity of the cooling system and insulation protection structure, effectively utilizes the internal space of the transformer, and thus reduces the area occupied by the transformer.

[0022] Furthermore, the radially concentric arrangement of the high-voltage on-load tap-changing winding and the medium-voltage on-load tap-changing winding reduces the influence of the high-voltage tap-changing electric field on the medium-voltage tap-changing electric field, reduces the use of insulation materials, and effectively reduces the height of the windings, thus lowering the overall height of the transformer and facilitating transportation. Secondly, this structure eliminates the need for complex transposition operations during winding, simplifying the winding process and improving production efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the winding arrangement of a large-capacity ultra-high voltage transformer with on-load tap changing in both high and medium voltage ranges.

[0024] Figure 2 This is a schematic diagram of the high-voltage and medium-voltage outputs of a large-capacity ultra-high voltage transformer with on-load tap changer for both high and medium voltage.

[0025] Figure 3 This is a high-voltage voltage regulation wiring diagram (facing the high-voltage side) of a large-capacity ultra-high-voltage transformer with on-load voltage regulation on both high-voltage and medium-voltage sides.

[0026] Figure 4 This is a schematic diagram of the low-voltage tap changing wiring of a large-capacity ultra-high voltage transformer with on-load tap changing on both high-voltage and medium-voltage sides (facing the high-voltage side).

[0027] Figure 5 This is a schematic diagram of the switch placement for a large-capacity ultra-high voltage transformer with on-load tap changing capabilities on both high and medium voltage levels.

[0028] Figure 6 This is a schematic diagram of two parallel circuits connected to the upper and lower leads of the high voltage regulation line;

[0029] Figure 7 This is a schematic diagram of the upper and lower parallel connections of the voltage regulating lead.

[0030] In the attached diagram: 1. Low-voltage winding; 2. Medium-voltage winding; 3. High-voltage winding; 4. High-voltage regulating winding; 41. Upper high-voltage regulating winding; 42. Lower high-voltage regulating winding; 43. High-voltage regulating lead; 5. Medium-voltage regulating winding; 51. Upper medium-voltage regulating winding; 52. Lower medium-voltage regulating winding; 53. Medium-voltage regulating lead; 6. High-voltage on-load switch; 7. Medium-voltage on-load switch; 8. Iron core. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0032] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0033] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or may be interposed with another element. The terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., used herein to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] A large-capacity ultra-high voltage transformer with on-load tap changers for both high and medium voltage is provided. In terms of technical parameters, it meets the requirements for transformer capacity, voltage, impedance, temperature rise, loss, and short-circuit withstand capability. Structurally, both high and medium voltage windings are set with independent windings, which are radially distributed. The high-voltage regulating winding is a double-helix type with the upper and lower windings connected in parallel, while the medium-voltage regulating winding is a continuous type with the upper and lower windings connected in parallel. It adopts dual on-load tap changers located on the same side and has a wide range of voltage regulation for both high and medium voltages with multiple stages.

[0036] Reference Figure 1This is a large-capacity ultra-high voltage transformer with on-load tap changing for both high and medium voltage. Both high and medium voltages are on-load tap changing, with separate high-voltage tap changing windings 4 and 5. It includes an iron core 8, low-voltage windings 1 and 2, high-voltage winding 3, high-voltage tap changing winding 4, and medium-voltage tap changing winding 5. The winding arrangement is as follows: iron core 8 - low-voltage winding 1 - low-voltage winding 2 - high-voltage winding 3 - high-voltage tap changing winding 4 - medium-voltage tap changing winding 5. The high-voltage tap changing winding 4 and the medium-voltage tap changing winding 5 are radially concentric. For a large-capacity ultra-high voltage three-phase transformer, using a center-outhead high-voltage winding 3 reduces uneven electrical stress distribution, lowers the risk of partial discharge, and improves insulation reliability; therefore, the high-voltage winding 3 uses a center-outhead design. The low-voltage winding 2 is located on the inner diameter side of the high-voltage winding 3; for ease of routing, the low-voltage winding 2 uses an end-outhead design. To avoid the high electric field region of the high-voltage outgoing line, the high-voltage regulating winding 4 is divided into an upper high-voltage regulating winding 41 and a lower high-voltage regulating winding 42, and the medium-voltage regulating winding 5 is divided into an upper medium-voltage regulating winding 51 and a lower medium-voltage regulating winding 52. The high-voltage regulating winding 4 and the medium-voltage regulating winding 5 are radially distributed, and their outlets are as follows: Figure 2 As shown. Among them, the upper high voltage regulating winding 41 is located directly above the lower high voltage regulating winding 42, and the upper medium voltage regulating winding 51 is located directly below the lower medium voltage regulating winding 52.

[0037] The main insulation and phase-to-phase insulation of large-capacity ultra-high voltage transformers with on-load tap changers for both high and medium voltage adopt a thin paper tube and small oil gap structure, which improves the distribution of electric field and increases the dielectric strength of insulation. At the same time, it ensures heat dissipation requirements, effectively avoids partial discharge of transformers during various insulation tests and long-term operation, and slows down insulation aging.

[0038] Preferably, an electrostatic plate is placed in the high field strength area at the first end of the high voltage winding 3.

[0039] The lead wire of the upper high voltage regulating winding 41 is led out from the upper part of the upper medium voltage regulating winding 51, and the lead wire of the lower high voltage regulating winding 42 is led out from the lower part of the lower medium voltage regulating winding 52.

[0040] like Figure 6 As shown, the high-voltage regulating lead 43 adopts two parallel connections, upper and lower, to connect the high-voltage regulating winding 4 after they are combined. The wiring principle is as follows: Figure 3 As shown.

[0041] like Figure 7 As shown, the intermediate voltage regulating lead 53 adopts two parallel connections, upper and lower, to connect the intermediate voltage regulating winding 5 after they are combined. The wiring principle is as follows: Figure 4 As shown.

[0042] like Figure 5As shown, the high-voltage on-load switch 6 and the medium-voltage on-load switch 7 are placed on the same side of the transformer body, which can reduce the floor space occupied by the transformer.

[0043] The high-voltage and medium-voltage voltage regulation range is wide and has many levels. The voltage regulation range of the high-voltage on-load switch 6 and the medium-voltage on-load switch 7 is 8×1.25%, that is, there are ±8 levels (a total of 17 levels). Each time the voltage is adjusted to 1.25%.

[0044] During high-medium operation, the voltage of low-voltage winding 2 is constant (rated tap), while the voltage of high-voltage winding 3 is adjustable under load.

[0045] During medium-low operation, the voltage of low-voltage winding 1 is constant, while the voltage of low-voltage winding 2 is adjustable under load.

[0046] During high-low operation, the voltage of low-voltage winding 1 is constant, while the voltage of high-voltage winding 3 is adjustable under load.

[0047] Through the above methods, the function of outputting different voltages for high voltage and medium voltage can be realized. The output voltage regulation range is wide and it can be connected to power grids of different voltage levels, reducing user investment.

[0048] The term "constituting of" in describing a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novel features of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, parts, or steps herein also contemplates embodiments that are essentially composed of such elements, components, parts, or steps. The use of the term "may" herein is intended to indicate that any described attribute included by "may" is optional.

[0049] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0050] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed utility model subject matter.

Claims

1. A large-capacity ultra-high voltage transformer with on-load tap changing capabilities for both high and medium voltage, characterized in that, The system includes, from the inside out, an iron core (8), a low-voltage winding (1), a medium-voltage winding (2), a high-voltage winding (3), a high-voltage regulating winding (4), and a medium-voltage regulating winding (5); the high-voltage winding (3) is connected to the high-voltage regulating winding (4) via a high-voltage on-load switch (6); the medium-voltage winding (2) is connected to the medium-voltage regulating winding (5) via a medium-voltage on-load switch (7); The high voltage regulating winding (4) includes an upper high voltage regulating winding (41) and a lower high voltage regulating winding (42) connected in parallel. The medium-voltage regulating winding (5) includes an upper medium-voltage regulating winding (51) and a lower medium-voltage regulating winding (52) connected in parallel.

2. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, An electrostatic plate is provided at the first end of the high-voltage winding (3).

3. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The voltage regulation range of both the high-voltage on-load switch (6) and the medium-voltage on-load switch (7) is 8 × 1.25%.

4. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The high-voltage regulating winding (4) is a double-helix winding.

5. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The medium-voltage regulating winding (5) is a continuous winding.

6. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The high-voltage on-load switch (6) and the medium-voltage on-load switch (7) are located on the same side of the iron core (8).

7. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The high-voltage winding (3) adopts a center-outlet configuration.

8. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The medium-voltage winding (2) adopts end-out wires.

9. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The lead wire of the upper high voltage regulating winding (41) is drawn from the upper part of the upper medium voltage regulating winding (51), and the lead wire of the lower high voltage regulating winding (42) is drawn from the lower part of the lower medium voltage regulating winding (52).

10. A large-capacity ultra-high voltage transformer with on-load tap changing in both high-voltage and medium-voltage sections according to claim 1, characterized in that, The high-voltage regulating winding (4) and the medium-voltage regulating winding (5) adopt a radial concentric structure.

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