A spare phase transformer suitable for multiple transformers

Abstract

The present invention belongs to the field of standby phase transformers, and specifically discloses a standby phase transformer adapted for multiple transformers, which includes: a medium voltage coil, an intermediate regulating coil, a high-voltage reactor, and a high-voltage coil connected in series; a plurality of high-voltage taps are provided on the high-voltage coil, and the high-voltage voltage can be adjusted by electrically connecting two different high-voltage taps; a plurality of high-voltage impedance taps are provided on the high-voltage reactor for connecting to the intermediate regulating coil, and different high-voltage impedance taps are electrically connected through the intermediate regulating coil to adjust the high-voltage impedance. The transformer of the present invention is convenient for voltage regulation, and the high-medium operating impedance is continuously adjustable. At the same time, it can be well matched with the impedance of other transformers, and the impedance deviation can be controlled to within ±2%, meeting the requirements of parallel operation. It can realize rapid replacement of transformers with the same capacity, has very strong versatility and interchangeability, reduces the impact of transformer failure on people's lives, reduces the impact on industrial production and reduces huge economic losses.

Description

Technical Field

[0001] The present invention belongs to the technical field of standby phase transformers, and in particular relates to a standby phase transformer adapted for multiple transformers. Background Art

[0002] At present, the high-voltage rated voltage of 500kV-level power transformers in my country's power transmission and transformation system is between 500-525kV, the medium-voltage rated voltage is mostly 230kV, the medium-voltage voltage regulation range is ±2×2.5%, and the high-medium rated tap impedance is between 12% and 24%. There are many voltage types and a large impedance range, so the main transformers in different substations generally have some differences in voltage and impedance.

[0003] Currently, 500kV substations are rarely equipped with spare transformers. Once a transformer fails, the entire transformer group is shut down and power can only be restored after repairs are completed or a new transformer is rebuilt according to the faulty transformer's parameters. This has a significant impact on industrial production and causes huge economic losses. Because transformers of the same capacity require the same voltage and impedance when operating in parallel, the main transformers in different substations are currently difficult to interchange due to differences in voltage and impedance. In order to enable transformers to serve as backup phases for transformers of different voltages and impedances, the development of a backup phase transformer that can simultaneously adjust voltage and impedance values ​​to adapt to multiple transformers has become an urgent problem to be solved. Summary of the Invention

[0004] The present invention provides a standby phase transformer adapted to multiple transformers, so as to solve the problem that the current standby phase transformer has low adaptability in voltage and impedance fixing.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows: a standby phase transformer adapted for multiple transformers, comprising: a medium voltage coil, an intermediate regulating coil, a high voltage reactor and a high voltage coil connected in series in sequence; the high voltage coil is provided with a plurality of high voltage tap points, and the high voltage voltage can be adjusted by electrically connecting two different high voltage tap points;

[0006] The high-voltage reactor is provided with a plurality of high-voltage impedance tapping points for connecting to the intermediate adjustment coil. Different high-voltage impedance tapping points are electrically connected through the intermediate adjustment coil to adjust the high-voltage impedance.

[0007] In a preferred embodiment of the present invention, it also includes a low-voltage coil, a low-voltage reactor and a low-voltage bushing connected in series in sequence. The low-voltage reactor is provided with at least three low-voltage tap points for connecting the low-voltage bushing. The low-voltage impedance can be adjusted by connecting different low-voltage tap points through the low-voltage bushing.

[0008] In a preferred embodiment of the present invention, one end of the low-voltage coil is connected to a low-voltage bushing and led out, and the other end of the low-voltage coil is electrically connected to a low-voltage reactor.

[0009] In a preferred embodiment of the present invention, the low-voltage reactor has m-1 tapping sections and m tapping points, where m is determined according to the transformer's medium-low operating impedance adjustment range and impedance deviation range.

[0010] In a preferred embodiment of the present invention, when the low-voltage reactor operates at tap point m, the transformer medium-low operating impedance is minimum, and when the low-voltage reactor operates at tap point 1, the transformer medium-low operating impedance is maximum.

[0011] In a preferred embodiment of the present invention, the medium regulating coil includes a first outlet terminal connected to the high-voltage reactor, a last outlet terminal electrically connected to the first outlet terminal of the medium-voltage coil, and a plurality of voltage regulating tapping points for connecting to the medium-voltage bushing. The medium voltage can be adjusted by connecting different voltage regulating tapping points through the medium-voltage bushing, and the last outlet terminal of the medium-voltage coil is connected to the neutral point bushing and led out.

[0012] In a preferred embodiment of the present invention, the high-voltage coil is of a central entry type, including an upper high-voltage coil and a lower high-voltage coil connected in parallel. High-voltage tap points are provided on both the upper high-voltage coil and the lower high-voltage coil. The two tap points on both sides of the interruption point of the upper high-voltage coil are bridge-connected, and the two tap points on both sides of the interruption point of the lower high-voltage coil are bridge-connected. When the transformer is running, the upper high-voltage coil and the lower high-voltage coil are bridged at the same tap point. The number of turns connected to the high-voltage coil is changed by changing the bridge tap point to adjust the high-voltage voltage.

[0013] In a preferred embodiment of the present invention, the end outlet terminal of the upper high-voltage coil and the end outlet terminal of the lower high-voltage coil are electrically connected to the current input terminal of the high-voltage reactor, and the first outlet terminal of the upper high-voltage coil and the first outlet terminal of the lower high-voltage coil are electrically connected to the high-voltage bushing.

[0014] In a preferred embodiment of the present invention, the high-voltage coil is of a central incoming line type, including an upper high-voltage coil and a lower high-voltage coil connected in parallel; an upper high-tune coil is provided outside the upper high-voltage coil, and the tap point provided at the upper high-tune coil is the upper high-voltage tap point; a lower high-voltage coil is provided outside the lower high-voltage coil, and the tap point provided at the lower high-voltage coil is the lower high-voltage tap point; an upper high-voltage tap point and a lower high-voltage tap point are electrically connected to the current input end of the high-voltage reactor, and the number of turns of the connected high-voltage coil is changed by changing the connection tap point to adjust the high-voltage voltage.

[0015] In a preferred embodiment of the present invention, the terminal end of the upper high-voltage coil is electrically connected to the terminal end of the upper high-voltage coil, and the terminal end of the lower high-voltage coil is electrically connected to the terminal end of the lower high-voltage coil. A tap point on the upper high-voltage coil and a tap point on the lower high-voltage coil are electrically connected to the current input terminal of the high-voltage reactor.

[0016] In a preferred embodiment of the present invention, the upper high-voltage tap points are numbered in ascending order from the end outlet terminal close to the high-voltage coil to the beginning outlet terminal close to the high-voltage coil, and the lower high-voltage tap points are numbered in ascending order from the end outlet terminal close to the lower high-voltage coil to the beginning outlet terminal close to the lower high-voltage coil. An upper high-voltage tap point is electrically connected to a lower high-voltage tap point with the same number, and the connected upper high-voltage tap points are adjusted in ascending order, and the high-voltage voltage is decreased in descending order.

[0017] In a preferred embodiment of the present invention, the high-voltage reactor has n-1 tapping sections and n tapping points, where n is determined according to the transformer's high-medium operating impedance adjustment range and impedance deviation range.

[0018] In a preferred embodiment of the present invention, when the high-voltage reactor operates at tap point n, the transformer high-medium operating impedance is minimum, and when the high-voltage reactor operates at tap point 1, the transformer high-medium operating impedance is maximum.

[0019] In a preferred embodiment of the present invention, the high-voltage reactor coil is of continuous type. The inner diameter and outer diameter of each stage of the high-voltage reactor are the same, but the number of turns and reactance height are different. The number of turns and reactance height of the coil are configured by formula 1 to achieve the same inductance and inductive reactance at each stage:

[0020]

[0021] Where L is the inductance, k is the coefficient, N is the number of coil turns, r is the average radius of the reactor coil, H is the reactor reactance height, and W is the reactor coil width.

[0022] The technical solution provided by the present invention has the following advantages compared with the prior art:

[0023] The 500kV transformer of the present invention can provide six high voltages: 500kV, 505kV, 510kV, 515kV, 520kV, and 525kV. It features a simple and convenient voltage regulation method, continuously adjustable high-medium operating impedance, and is fully applicable to the needs of current 500kV power transmission and transformation systems. It can also effectively match the impedance of other transformers, with impedance deviations controlled to within ±2%, meeting parallel operation requirements. It can be quickly replaced with transformers of the same capacity, demonstrating strong versatility and interchangeability. In the event of a failure or other abnormal condition involving a transformer of the same capacity, it can be directly replaced, quickly restoring power supply and reducing the impact of transformer failures on people's lives, industrial production, and significant economic losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, they can also obtain drawings of other embodiments based on these drawings.

[0025] Figure 1 This is a wiring diagram of a standby phase transformer adapted to multiple transformers according to one embodiment of the present invention;

[0026] Figure 2 This is a wiring schematic diagram of a tap changer for a standby phase transformer adapted to multiple transformers according to one embodiment of the present invention;

[0027] Figure 3 This is a wiring schematic diagram of a standby phase transformer adapted to multiple transformers according to another embodiment of the present invention. DETAILED DESCRIPTION

[0028] For ease of understanding, a standby phase transformer adapted to multiple transformers is described below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations and positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present 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.

[0030] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0031] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0032] like Figure 1 As shown, a standby phase transformer adapted to multiple transformers in the present invention includes a low-voltage coil, a low-voltage reactor, an intermediate regulating coil, a medium-voltage coil, a high-voltage coil, a high-voltage reactor, and a low-voltage coil.

[0033] A standby phase transformer adapted for multiple transformers, comprising: a low-voltage coil, a low-voltage reactor and a low-voltage bushing connected in series in sequence; a medium-voltage coil, an intermediate regulating coil, a high-voltage reactor and a high-voltage coil connected in series in sequence; a plurality of high-voltage tapping points are provided on the high-voltage coil, and the high-voltage voltage can be adjusted by electrically connecting two different high-voltage tapping points.

[0034] The low-voltage reactor is provided with at least three low-voltage tapping points for connecting low-voltage bushings. The low-voltage impedance can be adjusted by connecting different low-voltage tapping points through the low-voltage bushings.

[0035] One end of the low-voltage coil is connected to the low-voltage bushing and led out, and the other end of the low-voltage coil is electrically connected to the low-voltage reactor.

[0036] A low-voltage reactor has m-1 tapping sections and m tapping points, where m is determined by the transformer's medium-low operating impedance adjustment range and impedance deviation range. When the low-voltage reactor operates at tap point m, the transformer's medium-low operating impedance is minimum. When the low-voltage reactor operates at tap point 1, the transformer's medium-low operating impedance is maximum.

[0037] The medium regulating coil includes a first outlet terminal connected to the high-voltage reactor, a last outlet terminal electrically connected to the first outlet terminal of the medium-voltage coil, and multiple voltage regulating tapping points for connecting to the medium-voltage bushing. The medium voltage can be adjusted by connecting different voltage regulating tapping points through the medium-voltage bushing. The last outlet terminal of the medium-voltage coil is connected to the neutral point bushing and led out.

[0038] The high-voltage reactor is provided with a plurality of high-voltage impedance tapping points for connecting to the intermediate adjustment coil. By electrically connecting different high-voltage impedance tapping points through the intermediate adjustment coil, the high-voltage impedance can be adjusted.

[0039] In one embodiment of the present invention, the high-voltage coil is of a central entry type, including an upper high-voltage coil and a lower high-voltage coil connected in parallel. High-voltage tap points are provided on both the upper high-voltage coil and the lower high-voltage coil. The two tap points on both sides of the interruption point of the upper high-voltage coil are bridge-connected, and the two tap points on both sides of the interruption point of the lower high-voltage coil are bridge-connected. When the transformer is running, the upper high-voltage coil and the lower high-voltage coil are bridged at the same tap point. The number of turns connected to the high-voltage coil is changed by changing the bridge tap point to adjust the high-voltage voltage.

[0040] The end outlet terminal of the upper high-voltage coil and the end outlet terminal of the lower high-voltage coil are electrically connected to the current input terminal of the high-voltage reactor, and the beginning outlet terminal of the upper high-voltage coil and the beginning outlet terminal of the lower high-voltage coil are electrically connected to the high-voltage bushing.

[0041] Reference Figure 1 As shown, the high-voltage coil includes an upper high-voltage coil and a lower high-voltage coil connected in parallel. The upper high-voltage coil is provided with seven upper high-voltage tapping points, which are numbered 7, 5, 3, 2, 4, 6, and 8 from the first outlet end to the last outlet end of the upper high-voltage coil. The lower high-voltage coil is provided with seven lower high-voltage tapping points, which are numbered 7, 5, 3, 2, 4, 6, and 8 from the first outlet end to the last outlet end of the lower high-voltage coil. Figure 2 As shown, there are seven contacts on the tap changer, numbered 2, 3, 4, 5, 6, 7, and 8 respectively. The upper high-voltage tap point, lower high-voltage tap point, and contacts with the same number are electrically connected.

[0042] Reference Figure 2 As shown, when the target voltage is 525 kV, the tap changer is connected to the first tap level, which is the maximum tap level, and contacts No. 2 and No. 3 are connected to the circuit;

[0043] When the target voltage is 520 kV, the tap changer is connected to the second tap level, and contacts 3 and 4 are connected to the circuit;

[0044] When the target voltage is 515kV, the tap changer is connected to the three-stage tap changer, and contacts 4 and 5 are connected to the circuit;

[0045] When the target voltage is 510 kV, the tap changer is connected to the fourth tap level, and contacts 5 and 6 are connected to the circuit;

[0046] When the target voltage is 505 kV, the tap changer is connected to the fifth tap level, and contacts 6 and 7 are connected to the circuit;

[0047] When the target voltage is 500 kV, the tap changer is connected to the sixth tap level, which is the smallest tap level, and contacts No. 7 and No. 8 are connected to the circuit.

[0048] The low voltage impedance and the high voltage impedance adjust the tap points accordingly according to the target impedance values.

[0049] The high-voltage reactor has n-1 tapping sections and n tapping points, where n is determined by the transformer's high-to-medium operating impedance adjustment range and impedance deviation range. When the high-voltage reactor operates at tap point n, the transformer's high-to-medium operating impedance is minimum. When the high-voltage reactor operates at tap point 1, the transformer's high-to-medium operating impedance is maximum.

[0050] The high-voltage reactor coil type is continuous. The inner and outer diameters of each stage of the high-voltage reactor are the same, but the number of turns and reactance height are different. The number of turns and reactance height are configured through formula 1 to achieve the same inductance and inductive reactance at each stage:

[0051]

[0052] Where L is the inductance, k is the coefficient, N is the number of coil turns, r is the average radius of the reactor coil, H is the reactor reactance height, and W is the reactor coil width.

[0053] In another embodiment of the present invention, the high-voltage coil is of a central incoming line type, including an upper high-voltage coil and a lower high-voltage coil connected in parallel; an upper high-tune coil is provided outside the upper high-voltage coil, and the tap point provided at the upper high-tune coil is the upper high-voltage tap point; a lower high-tune coil is provided outside the lower high-voltage coil, and the tap point provided at the lower high-voltage coil is the lower high-voltage tap point; an upper high-voltage tap point and a lower high-voltage tap point are electrically connected to the current input end of the high-voltage inductor, and the number of turns of the connected high-voltage coil is changed by changing the connection tap point to adjust the high-voltage voltage.

[0054] The terminal of the upper high-voltage coil is electrically connected to the terminal of the upper high-voltage coil, and the terminal of the lower high-voltage coil is electrically connected to the terminal of the lower high-voltage coil. A tap point on the upper high-voltage coil and a tap point on the lower high-voltage coil are electrically connected to the current input terminal of the high-voltage reactor.

[0055] The upper high-voltage tap points are numbered in ascending order from the end of the high-voltage coil to the end of the high-voltage coil, and the lower high-voltage tap points are numbered in ascending order from the end of the lower high-voltage coil to the end of the lower high-voltage coil. When an upper high-voltage tap point is electrically connected to a lower high-voltage tap point with the same number, and the connected upper high-voltage tap point is adjusted in an ascending manner, the high-voltage voltage decreases.

[0056] like Figure 3As shown, the upper high-voltage coil has six upper high-voltage tapping points, numbered 1, 2, 3, 4, 5, and 6, from the terminal farthest from the upper high-voltage coil to the terminal closest to it. The lower high-voltage coil has six lower high-voltage tapping points, numbered 1, 2, 3, 4, 5, and 6, from the terminal farthest from the lower high-voltage coil to the terminal closest to it. Based on the target voltage, electrically connect the upper and lower high-voltage tapping points with the same number.

[0057] When the target voltage is 525kV, the No. 1 upper high-voltage tap point and the No. 1 lower high-voltage tap point are electrically connected to the current input terminal of the high-voltage reactor;

[0058] When the target voltage is 520kV, the No. 2 upper high-voltage tap point and the No. 2 lower high-voltage tap point are electrically connected to the current input terminal of the high-voltage reactor;

[0059] When the target voltage is 515kV, the No. 3 upper high-voltage tap point and the No. 3 lower high-voltage tap point are electrically connected to the current input terminal of the high-voltage reactor;

[0060] When the target voltage is 510kV, the No. 4 upper high-voltage tap point and the No. 4 lower high-voltage tap point are electrically connected to the current input terminal of the high-voltage reactor;

[0061] When the target voltage is 505kV, the No. 5 upper high-voltage tap point and the No. 5 lower high-voltage tap point are electrically connected to the current input terminal of the high-voltage reactor;

[0062] When the target voltage is 500kV, the No. 6 upper high-voltage tap point and the No. 6 lower high-voltage tap point are electrically connected to the current input terminal of the high-voltage reactor.

[0063] Other settings and adjustment methods are the same as those in the previous embodiment.

[0064] The 500kV transformer of the present invention can provide six high voltages: 500kV, 505kV, 510kV, 515kV, 520kV, and 525kV. It features a simple and convenient voltage regulation method, continuously adjustable high-medium operating impedance, and is fully applicable to the needs of current 500kV power transmission and transformation systems. It can also effectively match the impedance of other transformers, with impedance deviations controlled to within ±2%, meeting parallel operation requirements. It can be quickly replaced with transformers of the same capacity, demonstrating strong versatility and interchangeability. In the event of a fault or other abnormal condition involving another transformer of the same capacity, it can be directly replaced, quickly restoring power supply and reducing the impact of transformer failures on people's lives, industrial production, and significant economic losses.

[0065] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art will appreciate that the technical solutions described in the above embodiments may be modified or some or all of the technical features thereof may be replaced with equivalents, and that such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the various embodiments of the present invention.

Claims

1. A spare phase transformer adapted to multiple transformers, characterized in that: include: A medium voltage coil, a medium regulating coil, a high voltage reactor and a high voltage coil are sequentially connected in series; the high voltage coil is provided with a plurality of high voltage tapping points, and the high voltage voltage can be adjusted by electrically connecting two different high voltage tapping points; The high-voltage reactor is provided with a plurality of high-voltage impedance tapping points for connecting to the intermediate adjustment coil, and the high-voltage impedance is adjusted by electrically connecting different high-voltage impedance tapping points through the intermediate adjustment coil; The medium regulating coil includes a first outlet terminal connected to the high-voltage reactor, a last outlet terminal electrically connected to the first outlet terminal of the medium-voltage coil, and multiple voltage regulating tapping points for connecting to the medium-voltage bushing. The medium voltage can be adjusted by connecting different voltage regulating tapping points through the medium-voltage bushing. The last outlet terminal of the medium-voltage coil is connected to the neutral point bushing and led out.

2. The spare phase transformer adapted for multiple transformers according to claim 1, characterized in that: It also includes a low-voltage coil, a low-voltage reactor and a low-voltage bushing connected in series in sequence. The low-voltage reactor is provided with at least three low-voltage tap points for connecting the low-voltage bushing. The low-voltage impedance can be adjusted by connecting different low-voltage tap points through the low-voltage bushing.

3. The spare phase transformer adapted for multiple transformers according to claim 2, characterized in that: One end of the low-voltage coil is connected to the low-voltage bushing and led out, and the other end of the low-voltage coil is electrically connected to the low-voltage reactor.

4. The spare phase transformer adapted for multiple transformers according to claim 2, characterized in that: The low-voltage reactor has m-1 tapping sections and m tapping points, where m is determined according to the transformer's medium-low operating impedance adjustment range and impedance deviation range.

5. The spare phase transformer adapted for multiple transformers according to claim 2, characterized in that: When the low-voltage reactor operates at the tap point m, the transformer medium-low operating impedance is minimum; when the low-voltage reactor operates at the tap point 1, the transformer medium-low operating impedance is maximum.

6. The spare phase transformer adapted for multiple transformers according to claim 1, characterized in that: The high-voltage coil is of a central entry type, including an upper high-voltage coil and a lower high-voltage coil connected in parallel. Both the upper high-voltage coil and the lower high-voltage coil are provided with high-voltage tap points. The two tap points on both sides of the interruption point of the upper high-voltage coil are bridge-connected, and the two tap points on both sides of the interruption point of the lower high-voltage coil are bridge-connected. When the transformer is running, the upper high-voltage coil and the lower high-voltage coil are bridged at the same tap point. By changing the bridge tap point, the number of turns connected to the high-voltage coil is changed to adjust the high-voltage voltage.

7. The spare phase transformer adapted for multiple transformers according to claim 6, characterized in that: The end outlet terminal of the upper high-voltage coil and the end outlet terminal of the lower high-voltage coil are electrically connected to the current input terminal of the high-voltage reactor, and the beginning outlet terminal of the upper high-voltage coil and the beginning outlet terminal of the lower high-voltage coil are electrically connected to the high-voltage bushing.

8. The standby phase transformer regulation system adapted for multiple transformers according to claim 1, characterized in that: The high-voltage coil is of a central incoming line type, including an upper high-voltage coil and a lower high-voltage coil connected in parallel; an upper high-tune coil is provided outside the upper high-voltage coil, and the tap point provided on the upper high-tune coil is the upper high-voltage tap point; a lower high-voltage coil is provided outside the lower high-voltage coil, and the tap point provided on the lower high-voltage coil is the lower high-voltage tap point; an upper high-voltage tap point and a lower high-voltage tap point are electrically connected to the current input end of the high-voltage inductor, and the number of turns of the connected high-voltage coil is changed by changing the connection tap point to adjust the high-voltage voltage.

9. The spare phase transformer adapted for multiple transformers according to claim 8, characterized in that: The end outlet of the upper high-voltage coil is electrically connected to the beginning outlet of the upper high-tune coil, and the end outlet of the lower high-voltage coil is electrically connected to the beginning outlet of the lower high-tune coil; a tap point on the upper high-tune coil, a tap point on the lower high-tune coil and the current input end of the high-voltage reactor are electrically connected.

10. The spare phase transformer adapted for multiple transformers according to claim 9, characterized in that: The upper high-voltage tap points are numbered in ascending order from the end of the high-voltage coil to the end of the high-voltage coil, and the lower high-voltage tap points are numbered in ascending order from the end of the lower high-voltage coil to the end of the lower high-voltage coil. When an upper high-voltage tap point is electrically connected to a lower high-voltage tap point with the same number, and the connected upper high-voltage tap point is adjusted in an ascending manner, the high-voltage voltage decreases.

11. The spare phase transformer adapted for multiple transformers according to claim 1, characterized in that: The high-voltage reactor has n-1 tapping sections and n tapping points, where n is determined according to the transformer's high-medium operating impedance adjustment range and impedance deviation range.

12. The spare phase transformer adapted for multiple transformers according to claim 1, characterized in that: When the high-voltage reactor operates at the tap point n, the transformer high-medium operation impedance is minimum; when the high-voltage reactor operates at the tap point 1, the transformer high-medium operation impedance is maximum.

13. The spare phase transformer adapted for multiple transformers according to claim 1, characterized in that: The high-voltage reactor coil is of continuous type. The inner diameter and outer diameter of each stage of the high-voltage reactor are the same, but the number of turns and reactance height are different. The number of turns and reactance height are configured by formula 1 to achieve the same inductance and inductive reactance of each stage: Where L is the inductance, k is the coefficient, N is the number of coil turns, r is the average radius of the reactor coil, H is the reactor reactance height, and W is the reactor coil width.

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