Ultra-wide voltage-regulating 12-pulse rectification deicing transformer device and deicing method

Abstract

The application discloses a kind of super-wide voltage-regulating 12-pulse rectification ice-melting transformer device and ice-melting method, super-wide voltage-regulating 12-pulse rectification ice-melting transformer device includes autotransformer and 12-pulse rectification transformer, the output end of autotransformer is set as voltage multi-grade adjustable, 12-pulse rectification transformer includes rectification transformer body and two 12-pulse rectifiers, the primary side of rectification transformer body is connected with the output end of autotransformer, the secondary side of rectification transformer body is set as high-voltage gear and low-voltage gear, two 12-pulse rectifiers are respectively connected with high-voltage gear and low-voltage gear one-to-one, 12-pulse rectification transformer is used to select one from high-voltage gear and low-voltage gear according to the output voltage required by ice-melting and run, so that wide voltage output can be realized by gear combination of front and rear two-stage transformer, reach the purpose of ice-melting demand of super-wide voltage-regulating range of multiple lines.

Description

Technical Field

[0001] This invention belongs to the field of electrical engineering technology, and in particular relates to an ultra-wide voltage regulation 12-pulse rectifier de-icing transformer and de-icing method. Background Technology

[0002] my country is prone to ice and snow disasters. When power transmission lines are covered with ice, they are prone to breakage and pole collapse, which seriously threatens the safe operation of the power grid and the reliability of power supply. To address this, various types of ice-melting devices have been developed in China.

[0003] The de-icing devices used for main grid transmission lines typically have capacities of tens or even hundreds of megawatts. These large capacities and high costs are designed to meet the de-icing needs of lines within a certain range. Fixed DC de-icing devices built within substations generally need to meet the de-icing needs of all outgoing lines from that substation. Mobile, vehicle-mounted DC de-icing devices typically need to meet the de-icing needs of all easily de-iced lines within a certain area. Because the conductor specifications and lengths of various lines usually vary significantly, the output voltage of the de-icing device usually needs to be continuously adjustable over a wide range to meet the de-icing needs of all lines. Calculations show that the highest and lowest de-icing voltages for many substation lines differ by tens of times. For example, in a 220kV substation with 12 outgoing lines, the highest required de-icing voltage is 12.5kV, while the lowest is only 0.8kV, a difference of 16 times. Under such a wide voltage variation range, the design and manufacture of de-icing transformers become extremely difficult.

[0004] When the voltage regulation range required for on-site de-icing exceeds the range of a single 12-pulse rectifier de-icing transformer, a combination of two transformers is typically used. One large-capacity de-icing transformer corresponds to the higher output levels, while a smaller-capacity de-icing transformer corresponds to the lower output levels, thus meeting the wide-range de-icing requirements on-site. This approach necessitates two sets of de-icing transformers and their associated protection, monitoring, and fire-fighting equipment, resulting in a large footprint and high overall cost. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies of the prior art, the present invention provides an ultra-wide voltage regulation 12-pulse rectifier de-icing transformer device and de-icing method, aiming to solve the technical problem of the limited voltage regulation range of the existing 12-pulse rectifier de-icing transformer.

[0006] To achieve the above objectives, the present invention provides an ultra-wide voltage regulation 12-pulse rectifier de-icing transformer, wherein the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer includes an autotransformer and a 12-pulse rectifier transformer; the input terminal of the autotransformer is used to connect to the power grid, and the output terminal is configured to have multiple voltage levels adjustable; the 12-pulse rectifier transformer includes a rectifier transformer body and two 12-pulse rectifiers, the primary side of the rectifier transformer body is connected to the output terminal of the autotransformer, and the secondary side of the rectifier transformer body is configured with a high voltage level and a low voltage level, and the two 12-pulse rectifiers are respectively connected to the high voltage level and the low voltage level one-to-one, and the 12-pulse rectifier transformer is used to select one of the high voltage level and the low voltage level to operate according to the de-icing voltage required by the line to be de-iced.

[0007] In this embodiment of the invention, the voltage ratio of the high voltage level and the low voltage level is set to 4:1. The 12-pulse rectifier transformer is used to select the high voltage level when the de-icing voltage required for the line to be de-iced reaches 25% of the rated voltage, or to select the low voltage level when the de-icing voltage required for the line to be de-iced is less than 25% of the rated voltage.

[0008] In this embodiment of the invention, the voltage ratio between the highest and lowest output levels of the autotransformer is 4:1.

[0009] In this embodiment of the invention, the output voltage of the highest gear is set to be equal to the rated input voltage of the autotransformer, and the output voltage of the lowest gear is set to 1 / 4 of the rated input voltage of the autotransformer.

[0010] In this embodiment of the invention, the output terminal of the autotransformer is provided with a plurality of first taps, and each first tap is connected to a first voltage regulating switch for selecting the tap level.

[0011] In this embodiment of the invention, the rectifier transformer body adopts a three-phase winding connection method of Yy0d11.

[0012] In this embodiment of the invention, the primary side of the rectifier transformer body is configured as a delta-connected winding, and each coil winding in the primary delta-connected winding has 50 turns; the secondary side of the rectifier transformer body includes a delta-connected winding and a star-connected winding, and each coil winding in the secondary delta-connected winding has 20 turns and each coil winding in the star-connected winding has 12 turns.

[0013] In this embodiment of the invention, the short-circuit impedance of the autotransformer is 1%, and the short-circuit impedance of the 12-pulse rectifier transformer is 5%.

[0014] In this embodiment of the invention, the coil winding of the rectifier transformer body is provided with a high-range tap and a low-range tap, and a second voltage regulating switch is connected to both the high-range tap and the low-range tap to select the range.

[0015] To achieve the above objectives, the present invention also provides an ultra-wide voltage regulation de-icing method, wherein the ultra-wide voltage regulation de-icing method is applied to the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer described above, and includes:

[0016] The system selects between high and low voltage settings based on the required de-icing voltage for the circuit to be de-iced, and adjusts the tap of the autotransformer accordingly.

[0017] Through the above technical solution, the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer provided in this embodiment of the invention has the following beneficial effects:

[0018] When using the aforementioned ultra-wide voltage regulation 12-pulse rectifier de-icing transformer, since it connects an autotransformer with an adjustable output voltage range and a 12-pulse rectifier transformer with high and low voltage ranges on the secondary side in series, when the de-icing voltage required by the line to be de-iced is high, the 12-pulse rectifier transformer can be operated at the high voltage range, and the autotransformer's range can be adjusted; when the de-icing voltage required by the line to be de-iced is low, the 12-pulse rectifier transformer can be operated at the low voltage range, and the autotransformer's range can be adjusted. Thus, a wide voltage range output can be achieved through the range combination of the two transformers, while the impedance of each range can be significantly compressed within the allowable range. Therefore, a single transformer can meet the de-icing needs of multiple lines with an ultra-wide voltage regulation range.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a schematic diagram of the structure of an ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures

[0023] 100 autotransformer, 200 12-pulse rectifier transformer

[0024] 201 Rectifier Transformer Body; 202 12-Pulse Rectifier

[0025] 203 High voltage setting 204 Low voltage setting Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] Because the conductor specifications and lengths of various lines typically differ significantly, the output voltage of the de-icing device usually needs to be continuously adjustable over a wide range to meet the de-icing requirements of each line. Calculations show that the highest and lowest de-icing voltages for many substation lines differ by tens of times. For example, in a 220kV substation with 12 outgoing lines, the highest required de-icing voltage is 12.5kV, while the lowest is only 0.8kV, a difference of 16 times. Under such a wide voltage variation range, the design and manufacture of de-icing transformers become extremely difficult.

[0028] This is because when the de-icing transformer uses secondary-side voltage regulation, the 12-pulse rectifier transformer needs to control the secondary-side voltage difference between star and delta connections within 1%, and the number of turns can only be an integer. However, the star and delta connections inherently differ by a factor of 1.732, and the number of coil turns can only be selected within a suitable integer range to control the secondary-side output voltage appropriately, such as 5 turns for delta connection and 3 turns for star connection. Due to these rounding of turns and the existence of the turn number matching relationship between star and delta windings, a wider voltage regulation range will not only lead to an excessive number of turns on the primary and secondary sides, but also... The number of turns matching for each tap requires repeated design and trial and error. Since the output current of each tap of the de-icing transformer is generally as high as thousands of amperes to meet the de-icing current requirements, it will also lead to a significant increase in the cost and size of the transformer. When the de-icing transformer uses primary-side voltage regulation, under the condition that the de-icing current of each tap is the same, the transformer internal impedance is inversely proportional to the output voltage. The internal impedance at low output voltage will be tens of times higher than the rated impedance, or even more than 100%. The internal impedance voltage drop is large, making it difficult for the device to output the required de-icing voltage and current. Moreover, the port voltage varies greatly under different load currents, which is not conducive to the regulation of de-icing voltage and current.

[0029] Due to the above issues, the voltage regulation range of current 12-pulse rectifier-type de-icing transformers is generally limited to about 80%, meaning the lowest secondary voltage is approximately 20% of the highest output voltage. When the required voltage regulation range for on-site de-icing exceeds 80%, a combination of two transformers is typically used: one large-capacity de-icing transformer for the higher output levels and one small-capacity de-icing transformer for the lower output levels, thus meeting the wide-range de-icing requirements. This approach necessitates two sets of de-icing transformers and their associated protection, monitoring, and fire-fighting equipment, resulting in a large footprint and high overall cost.

[0030] The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to the present invention is described below with reference to the accompanying drawings.

[0031] like Figure 1 As shown, in an embodiment of the present invention, an ultra-wide voltage regulation 12-pulse rectifier de-icing transformer is provided, wherein the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer includes:

[0032] The autotransformer 100 has an input terminal for connection to the power grid and an output terminal that is adjustable in multiple voltage ranges.

[0033] The 12-pulse rectifier transformer 200 includes a rectifier transformer body 201 and two 12-pulse rectifiers 202. The primary side of the rectifier transformer body 201 is connected to the output terminal of the autotransformer 100. The secondary side of the rectifier transformer body 201 is configured with a high voltage range 203 and a low voltage range 204. The two 12-pulse rectifiers 202 are respectively connected to the high voltage range 203 and the low voltage range 204. The 12-pulse rectifier transformer 200 is used to select one of the high voltage range 203 and the low voltage range 204 to operate according to the de-icing voltage required by the line to be de-iced.

[0034] When using the aforementioned ultra-wide voltage regulation 12-pulse rectifier de-icing transformer, since the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer connects an autotransformer 100 with an adjustable output voltage range and a 12-pulse rectifier transformer 200 with a high voltage range 203 and a low voltage range 204 on its secondary side, when the de-icing voltage required by the line to be de-iced is high, the 12-pulse rectifier transformer 200 can be operated at the high voltage range 203, and the range of the autotransformer 100 can be adjusted; when the de-icing voltage required by the line to be de-iced is low, the 12-pulse rectifier transformer 200 can be operated at the low voltage range 204, and the range of the autotransformer 100 can be adjusted. Thus, a wide voltage output can be achieved through the range combination of the two transformer stages, and the impedance of each range can be greatly compressed within the allowable range. Therefore, a single transformer can meet the de-icing needs of multiple lines with an ultra-wide voltage regulation range.

[0035] In this embodiment of the invention, the voltage ratio of the high voltage setting 203 and the low voltage setting 204 can be set to 4:1. The 12-pulse rectifier transformer 200 is used to select the high voltage setting 203 to operate when the de-icing voltage required for the line to be de-iced reaches 25% of the rated voltage, or to select the low voltage setting 204 to operate when the de-icing voltage required for the line to be de-iced is less than 25% of the rated voltage. When the de-icing voltage required for the circuit to be de-iced is 25% to 100% of the rated voltage, the downstream rectifier transformer operates at the high voltage setting 203, and the upstream autotransformer 100 adjusts its voltage range. At this time, the short-circuit impedance of each setting will not exceed four times the rated voltage. When the de-icing voltage required for the circuit to be de-iced is less than 20% of the rated voltage, the downstream rectifier transformer operates at the low voltage setting 204, and the output voltage is 1 / 4 of that when connected to the high voltage setting 203. Combined with the upstream autotransformer 100, the minimum output voltage can be further reduced, and at the same time, its short-circuit impedance will not exceed four times the rated voltage.

[0036] In this embodiment of the invention, the voltage ratio of the highest and lowest output levels of the autotransformer 100 is 4:1. That is, the voltage regulation depth of the preceding autotransformer 100 is set to 80%. When the subsequent rectifier transformer operates at the low voltage level 204, the lowest output voltage of the de-icing transformer can reach 1 / 20 of the rated output voltage of the secondary side. Thus, within the range where the ratio of the highest to lowest output voltage of the de-icing transformer reaches 20 times, the impedance change does not exceed 4 times, which is far lower than the short-circuit impedance when relying solely on the autotransformer 100 for voltage regulation in the traditional way.

[0037] In this embodiment of the invention, the output voltage of the highest gear is set to be equal to the rated input voltage of the autotransformer 100, and the output voltage of the lowest gear is set to 1 / 4 of the rated input voltage of the autotransformer 100.

[0038] In this embodiment of the invention, the output terminal of the autotransformer 100 is provided with a plurality of first taps, and each first tap is connected to a first voltage regulating switch for range selection. That is, by controlling the opening and closing of the first voltage regulating switch on each first tap, the range of the autotransformer 100 can be selected. Specifically, the number of first taps and first voltage regulating switches can both be six. The six first taps are spaced apart on the coil winding at the output terminal of the autotransformer 100, and the six first voltage regulating switches are connected one-to-one with the six first taps. Furthermore, the first voltage regulating switches are non-excitation voltage regulating switches.

[0039] In this embodiment of the invention, the rectifier transformer body 201 can adopt a three-phase winding connection method of Yy0d11.

[0040] In this embodiment of the invention, the primary side of the rectifier transformer body 201 is configured as a delta-connected winding, and each coil winding in the primary delta-connected winding has 50 turns. The secondary side of the rectifier transformer body 201 includes a delta-connected winding and a star-connected winding, and each coil winding in the secondary delta-connected winding has 20 turns and each coil winding in the star-connected winding has 12 turns. When the secondary side corresponds to the high voltage level 203, each coil winding in the delta-connected winding of the secondary side of the 12-pulse rectifier transformer 200 is connected to 20 turns, and each coil winding in the star-connected winding is connected to 12 turns. When the secondary side corresponds to the low voltage level 204, each coil winding in the delta-connected winding of the secondary side of the 12-pulse rectifier transformer 200 is connected to 5 turns, and each coil winding in the star-connected winding is connected to 3 turns.

[0041] In this embodiment of the invention, the short-circuit impedance of the autotransformer 100 is 1%, and the short-circuit impedance of the 12-pulse rectifier transformer 200 is 5%.

[0042] In this embodiment of the invention, the coil winding of the rectifier transformer body 201 is provided with a high-range tap and a low-range tap. A second voltage regulating switch is connected to both the high-range and low-range taps to select the tap position. That is, by controlling the opening and closing of the second voltage regulating switch between the high-range and low-range taps, the high-range and low-range taps can be selected. Furthermore, the second voltage regulating switch can also be a non-excitation voltage regulating switch.

[0043] To achieve the above objectives, the present invention also provides an ultra-wide voltage regulation de-icing method, wherein the ultra-wide voltage regulation de-icing method is applied to the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer described above, and includes:

[0044] The system selects one of the high voltage setting 203 and the low voltage setting 204 to operate based on the de-icing voltage required for the circuit to be de-iced, and adjusts the setting of the autotransformer 100.

[0045] Specifically, a threshold can be preset for the de-icing voltage. After determining the required de-icing voltage for the line to be de-iced, the de-icing voltage is compared with the preset threshold. If the de-icing voltage reaches the preset threshold, the high voltage setting 203 is selected for operation and the setting of the autotransformer 100 is adjusted. If the de-icing voltage is lower than the preset threshold, the low voltage setting 204 is selected for operation and the setting of the autotransformer 100 is adjusted.

[0046] When using the aforementioned ultra-wide voltage regulation de-icing method, the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer connects an autotransformer 100 with an adjustable output voltage range and a 12-pulse rectifier transformer 200 with a high voltage range 203 and a low voltage range 204 on its secondary side in series. When the de-icing voltage required for the line to be de-iced is high, the 12-pulse rectifier transformer 200 can be operated at the high voltage range 203, and the autotransformer 100 can be adjusted. When the de-icing voltage required for the line to be de-iced is low, the 12-pulse rectifier transformer 200 can be operated at the low voltage range 204, and the autotransformer 100 can be adjusted. Thus, a wide voltage output can be achieved through the combination of the ranges of the two transformers, while the impedance of each range can be significantly compressed within the allowable range. Therefore, a single transformer can meet the de-icing needs of multiple lines with an ultra-wide voltage regulation range.

[0047] Specifically, the input rated voltage of the autotransformer 100 of the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer is 10kV, and the output is set with six voltage levels: 10.0kV, 8.0kV, 6.0kV, 4.5kV, 3.2kV, and 2.5kV. The input of the autotransformer 100 is connected to a 10kV power grid. The 12-pulse rectifier transformer 200 adopts a Yy0d11 three-phase winding connection method, with a primary rated voltage of 10kV and a secondary rated voltage of 4.0kV (high voltage level). The 12-pulse rectifier transformer 200 has two taps: a rated voltage of 0.8kV (low voltage tap 204). The primary side of the rectifier transformer 200 has a three-phase delta connection with 50 turns. The secondary side has 20 turns in the delta winding and 12 turns in the star winding. When the secondary side is in the high voltage tap 203, the delta and star windings are connected to 20 and 12 turns respectively. When the secondary side is in the low voltage tap 204, the delta and star windings are connected to 5 and 3 turns respectively. Furthermore, the short-circuit impedance of the preceding autotransformer is designed to be 1%, and the short-circuit impedance of the following 12-pulse rectifier transformer 200 is designed to be 5%.

[0048] When the de-icing voltage requirement of the line to be de-iced is between 2.5kV and 10kV, the downstream rectifier transformer is connected to the 4kV high voltage setting 203. At this time, by adjusting the six settings of the upstream autotransformer 100, the overall output of the de-icing transformer device is obtained as 10.0kV, 8.0kV, 6.0kV, 4.5kV, 3.2kV, and 2.5kV respectively. When the de-icing voltage requirement of the line to be de-iced is below 2.5kV, the downstream rectifier transformer operates at the 1.0kV low voltage setting 204. At this time, by adjusting the six settings of the upstream autotransformer 100, the overall output of the de-icing transformer device is obtained as 2.0kV, 1.6kV, 1.2kV, 0.9kV, 0.64kV, and 0.5kV respectively. Thus, by combining the taps of the two transformers, a wide voltage output of 12 taps can be achieved: 10.0kV, 8.0kV, 6.0kV, 4.5kV, 3.2kV, 2.5kV, 2.0kV, 1.6kV, 1.2kV, 0.9kV, 0.64kV, and 0.5kV.

[0049] The present invention has the following advantages:

[0050] 1. The voltage regulation range of the de-icing transformer is extremely wide, and the maximum impedance is limited to a small range, so that one de-icing transformer can meet the de-icing needs of multiple lines.

[0051] 2. The adjustment range of the 12-pulse rectifier transformer 200 in the subsequent stage is relatively narrow. When the 12-pulse rectifier transformer 200 requires one star connection and one delta connection of the secondary winding, it is easy to make the number of turns of the secondary winding an integer, which helps to reduce the number of turns of the primary and secondary windings, and reduce the consumption of transformer winding wires and operating losses.

[0052] 3. Decoupling between the front and rear stages is achieved. The autotransformer 100 in the front stage no longer needs to consider the voltage imbalance deviation of the two windings on the secondary side, and the accuracy requirement is not high. The 12-pulse rectifier transformer 200 in the rear stage only needs to be configured with two fixed taps. Its winding turns are easy to round up, and it is easy to achieve low deviation of the secondary output voltage.

[0053] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0056] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A wide-range voltage regulation 12-pulse rectifier de-icing transformer, characterized in that, include: An autotransformer (100) is provided, wherein the input terminal of the autotransformer (100) is used to connect to the power grid, and the output terminal is configured to have multiple adjustable voltage levels. A 12-pulse rectifier transformer (200) includes a rectifier transformer body (201) and two 12-pulse rectifiers (202). The primary side of the rectifier transformer body (201) is connected to the output terminal of the autotransformer (100). The secondary side of the rectifier transformer body (201) is configured with a high voltage range (203) and a low voltage range (204). The two 12-pulse rectifiers (202) are respectively connected to the high voltage range (203) and the low voltage range (204). The 12-pulse rectifier transformer (200) is used to select one of the high voltage range (203) and the low voltage range (204) to operate according to the de-icing voltage required by the line to be de-iced. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer device is configured to output a wide voltage range through the tap combination of the front and rear transformers, and is configured as follows: If the de-icing voltage reaches the preset threshold, the high voltage setting (203) is selected for operation and the setting of the autotransformer (100) is adjusted. If the de-icing voltage is lower than the preset threshold, the low voltage setting (204) is selected for operation and the setting of the autotransformer (100) is adjusted.

2. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to claim 1, characterized in that, The voltage ratio of the high voltage level (203) and the low voltage level (204) is set to 4:

1. The 12-pulse rectifier transformer (200) is used to select the high voltage level (203) to operate when the de-icing voltage required for the line to be de-iced reaches 25% of the rated voltage, or to select the low voltage level (204) to operate when the de-icing voltage required for the line to be de-iced is less than 25% of the rated voltage.

3. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to claim 1, characterized in that, The voltage ratio between the highest and lowest output levels of the autotransformer (100) is 4:

1.

4. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to claim 3, characterized in that, The output voltage of the highest gear is set to be equal to the rated input voltage of the autotransformer (100), and the output voltage of the lowest gear is set to 1 / 4 of the rated input voltage of the autotransformer (100).

5. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to claim 1, characterized in that, The output terminal of the autotransformer (100) is provided with multiple first taps, and each first tap is connected to a first voltage regulating switch for selecting the voltage level.

6. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to any one of claims 1 to 5, characterized in that, The rectifier transformer body (201) adopts a three-phase winding connection method of Yy0d11.

7. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to claim 6, characterized in that, The primary side of the rectifier transformer body (201) is configured as a delta-connected winding, and each coil winding in the primary delta-connected winding has 50 turns; the secondary side of the rectifier transformer body (201) includes a delta-connected winding and a star-connected winding, and each coil winding in the secondary delta-connected winding has 20 turns and each coil winding in the star-connected winding has 12 turns.

8. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to any one of claims 1 to 5, characterized in that, The short-circuit impedance of the autotransformer (100) is 1%, and the short-circuit impedance of the 12-pulse rectifier transformer (200) is 5%.

9. The ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to any one of claims 1 to 5, characterized in that, The coil winding of the rectifier transformer body (201) is provided with a high-range tap and a low-range tap. A second voltage regulating switch is connected to both the high-range tap and the low-range tap to select the range.

10. A method for melting ice with ultra-wide voltage regulation, characterized in that, The ultra-wide voltage regulation de-icing method is applied to the ultra-wide voltage regulation 12-pulse rectifier de-icing transformer according to any one of claims 1 to 9, and includes: The high voltage setting (203) and the low voltage setting (204) are selected for operation according to the de-icing voltage required for the line to be de-iced, and the setting of the autotransformer (100) is adjusted.

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