Neutral point positive and negative regulation system for ultrahigh-voltage full-range voltage regulation intermediate transformer

Abstract

The utility model relates to a neutral point positive and negative regulation system for an ultrahigh-voltage full-range voltage regulation intermediate transformer, which comprises an upper voltage regulation coil, a lower voltage regulation coil and a switch body, the switch body comprises a regulation connecting line, a regulation moving contact and two regulation switches, the regulation connecting line is connected with the tail end of a high-voltage coil group on a corresponding core column of the transformer, and the regulation moving contact is connected with the two regulation switches. Meanwhile, the two ends of the adjusting connecting wire are connected with the adjusting switches on the corresponding sides respectively, the upper voltage adjusting coil and the lower voltage adjusting coil control positive and negative gear switching through the adjusting switches on the corresponding sides respectively, a plurality of upper voltage adjusting static contacts are arranged on the upper voltage adjusting coil, and a plurality of lower voltage adjusting static contacts are arranged on the lower voltage adjusting coil. And one end of the adjusting moving contact is in contact with the corresponding upper voltage regulation static contact, and the other end of the adjusting moving contact is in contact with the corresponding lower voltage regulation static contact. According to the utility model, 33-shift output voltage is provided under each input voltage, and 66-shift different voltage output can be further realized in cooperation with series-parallel connection conversion adjustment of the high-voltage coil group.

Description

Technical Field

[0001] The utility model relates to the technical field of intermediate transformers, in particular to a neutral point positive and negative regulation system for an ultra-high voltage full-range voltage regulating intermediate transformer. Background Art

[0002] The output voltage provided by the intermediate transformer in the existing technology is mostly at or below 110kV, and the voltage regulation range is within ±30%. However, with the increase in grid voltage level and the diversification of equipment types, the existing intermediate transformer can no longer meet the testing needs of new equipment. The commonly used solution is to use a combination of multiple devices or indirectly meet the product testing needs by transmitting from low voltage, but this will have different degrees of impact on the test cycle, operational safety and data accuracy, making it difficult to achieve the desired effect.

[0003] If the above problems need to be completely solved, it is necessary to develop an intermediate transformer with a sufficiently high voltage level and full-range voltage regulation, which can be compatible with existing electrical equipment and meet the test requirements of new electrical equipment. Among them, the research and development of voltage regulating switches is particularly critical. The voltage regulating switch conversion in the existing technology mainly focuses on series-parallel conversion or conversion of different connection forms, and it is difficult to further improve the adjustment range of the intermediate transformer.

[0004] For example, the Chinese utility model patent with authorization announcement number CN205508601U discloses an experimental three-phase intermediate transformer that combines series-parallel and star-delta transformations, in which the first inner winding and the second inner winding of each phase inner coil can be transformed into series and parallel forms through an internal voltage-regulating switch, while the first outer winding and the second outer winding of the three-phase outer coil of the device are mainly transformed into four forms of series, parallel, star and delta through an external voltage-regulating switch, and the range of variation is limited.

[0005] For example, a Chinese utility model patent with authorization announcement number CN209312580U discloses a no-load voltage-regulating intermediate transformer, which uses a star-delta conversion switch to switch between star and delta connections between windings, and uses a series-parallel switch to switch between series connection and parallel connection between coils in the same winding. The taps led out from the winding coils are respectively connected to the contacts on the double-bridge jumper switch, and different voltages are output by switching different gears on the double-bridge jumper switch. However, the device can only achieve 20 levels of output voltage adjustment. Utility Model Content

[0006] The purpose of the utility model is to provide a neutral point positive and negative adjustment system for an ultra-high voltage full-range voltage-regulating intermediate transformer, which has 33 levels of output voltage under each input voltage, and combined with the series-parallel conversion adjustment of the upper high-voltage coil and the lower high-voltage coil, it can further achieve 66 levels of different voltage outputs, which can make the voltage level of the intermediate transformer high enough and achieve full-range voltage regulation.

[0007] The purpose of this utility model is achieved through the following technical solutions:

[0008] A neutral point positive and negative adjustment system for an ultra-high voltage full-range voltage regulating intermediate transformer comprises an upper voltage regulating coil, a lower voltage regulating coil and a switch body, wherein the switch body comprises an adjustment connecting line, an adjustment moving contact and two adjustment switches, the adjustment connecting line is connected to the end of the high-voltage coil group on the corresponding core column of the transformer, and at the same time, the two ends of the adjustment connecting line are respectively connected to the adjustment switches on the corresponding sides, the upper voltage regulating coil and the lower voltage regulating coil respectively control the positive and negative gear conversion through the adjustment switches on the corresponding sides, the upper voltage regulating coil is provided with a plurality of upper voltage regulating static contacts, the lower voltage regulating coil is provided with a plurality of lower voltage regulating static contacts, and one end of the adjustment moving contact is in contact with the corresponding upper voltage regulating static contact, and the other end is in contact with the corresponding lower voltage regulating static contact, and each adjustment moving contact is connected to the neutral point connecting line.

[0009] The lead-out line at the head end of the upper voltage regulating coil is connected to the first upper switch contact, and the lead-out line at the tail end is connected to the second upper switch contact. A first regulating switch is provided at one end of the regulating connecting line, and when the first regulating switch contacts the first upper switch contact, the upper voltage regulating coil is connected in the forward direction, and when the first regulating switch contacts the second upper switch contact, the upper voltage regulating coil is connected in the reverse direction.

[0010] The lead-out line at the head end of the lower voltage regulating coil is connected to the first lower switch contact, and the lead-out line at the tail end is connected to the second lower switch contact. A second regulating switch is provided at one end of the regulating connecting line, and when the second regulating switch contacts the first lower switch contact, the lower voltage regulating coil is connected in the forward direction, and when the second regulating switch contacts the second lower switch contact, the lower voltage regulating coil is connected in the reverse direction.

[0011] The high-voltage coil group includes an upper high-voltage coil and a lower high-voltage coil, and a terminal of the lower high-voltage coil is connected to the adjustment connection line.

[0012] The upper high-voltage coil and the lower high-voltage coil are controlled to be converted into series and parallel via corresponding high-voltage series-parallel voltage regulating switches.

[0013] The high-voltage series-parallel voltage regulating switch includes a high-voltage upper contact and a high-voltage lower contact, wherein the a1 contact on the high-voltage series-parallel voltage regulating switch is connected to the head end of the upper high-voltage coil through a connecting line, the a2 contact is connected to the head end of the lower high-voltage coil through a connecting line, the a3 contact is connected to the end of the upper high-voltage coil through a connecting line, and at the same time, the a3 contact is connected to the a4 contact through a first connecting line, the a5 contact is connected to the end of the lower high-voltage coil through a connecting line, the a6 contact is empty, the high-voltage upper contact is in contact with the a1, a2, and a3 contacts, and the high-voltage lower contact is in contact with the a4, a5, and a6 contacts.

[0014] 1. The utility model is a neutral point positive and negative adjustment system with ±16 gears, which is configured at the neutral point of the high-voltage side. The upper voltage regulating coil and the lower voltage regulating coil can realize the "positive" gear and the "reverse" gear adjustment, and then can realize the output of 33 different voltage values, and then cooperate with the series-parallel conversion adjustment of the upper high-voltage coil and the lower high-voltage coil, so as to further realize 66 different voltage outputs.

[0015] 2. The voltage level of the intermediate transformer of the utility model is high enough and can achieve full-range voltage regulation, which is compatible with existing electrical equipment and meets the test requirements of new electrical equipment. It can meet the applicable range of more frequencies and the partial discharge is less than 30pC. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] Figure 2 This is a schematic diagram of the wiring principle when the transformers of the utility model are operated in parallel.

[0018] Figure 3 for Figure 2 The structural diagram of each phase high voltage coil,

[0019] Figure 4 for Figure 2 The structural diagram of the low-voltage coils of each phase,

[0020] Figure 5 This is a schematic diagram of the wiring principle when the transformer of the utility model is connected in series.

[0021] Figure 6 for Figure 5 The structural diagram of each phase high voltage coil,

[0022] Figure 7 for Figure 5 The structural diagram of the low-voltage coils of each phase,

[0023] Figure 8 This is a schematic diagram of a transformer coil wound on an iron core using the utility model.

[0024] Fig. 9 The schematic diagram of the transformer structure using the utility model is as follows:

[0025] Fig.10 for Fig. 9 Schematic diagram of the core structure.

[0026] Among them, 1 is the upper high-voltage coil, 2 is the lower high-voltage coil, 3 is the upper voltage regulating coil, 301 is the upper voltage regulating static contact, 302 is the first upper switch contact, 303 is the second lower switch contact, 4 is the lower voltage regulating coil, 401 is the lower voltage regulating static contact, 402 is the first lower switch contact, 403 is the second lower switch contact, 5 is the upper low-voltage coil, 6 is the lower low-voltage coil, 7 is the high-voltage series-parallel voltage regulating switch, 701 is High voltage upper contact, 702 is high voltage lower contact, 703 is the first connecting line, 8 is the low voltage series-parallel voltage regulating switch, 801 is the low voltage upper contact, 802 is the low voltage lower contact, 803 is the second connecting line, 9 is the switch body, 901 is the regulating moving contact, 902 is the second regulating switch, 903 is the first regulating switch, 904 is the regulating connecting line, 10 is the neutral point connecting line, 11 is the iron core, 12 is the ground screen, and 13 is the oil tank. DETAILED DESCRIPTION

[0027] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0028] like Figure 1 As shown, the utility model includes an upper voltage regulating coil 3, a lower voltage regulating coil 4 and a switch body 9, wherein the switch body 9 includes an adjustment connecting wire 904, an adjustment moving contact 901 and two adjustment switches, such as Figure 2 and Figure 5 As shown, the adjustment connecting line 904 is connected to the end of the high-voltage coil group on the corresponding core of the transformer. Figure 1 As shown, both ends of the regulating connecting line 904 are respectively connected to the regulating switches on the corresponding sides, and the upper voltage regulating coil 3 and the lower voltage regulating coil 4 respectively realize forward and reverse gear conversion through the regulating switches on the corresponding sides, and the upper voltage regulating coil 3 is provided with a plurality of upper voltage regulating static contacts 301, and the lower voltage regulating coil 4 is provided with a plurality of lower voltage regulating static contacts 401, and one end of the regulating moving contact 901 is in contact with the corresponding upper voltage regulating static contact 301, and the other end is in contact with the corresponding lower voltage regulating static contact 401, and each regulating moving contact 901 is connected to the neutral point connecting line 10.

[0029] like Figure 2As shown, in this embodiment, the upper voltage regulating coil 3 and the lower voltage regulating coil 4 are both continuously wound and in opposite directions, wherein the upper voltage regulating coil 3 is wound to the right and the lower voltage regulating coil 4 is wound to the left. The upper voltage regulating coil 3 and the lower voltage regulating coil 4 are arranged as a voltage regulating unit for each two coils corresponding to the coil height direction, so there are 16 voltage regulating units in total, and the utility model controls the movement of the regulating moving contact 901 so that the contacts at both ends thereof contact the upper voltage regulating static contact 301 and the lower voltage regulating static contact 401 in the corresponding voltage regulating unit, thereby achieving the purpose of adjusting the number of turns and voltage. In addition, as Figure 2 As shown, both ends of the adjustment connection line 904 are provided with a K point connected to the adjustment switch on the corresponding side, and the lead-out line at the head end of the upper voltage regulating coil 3 is connected to the first upper switch contact 302, and the lead-out line at the tail end is connected to the second upper switch contact 303, and the first adjustment switch 903 corresponding to the upper voltage regulating coil 3 realizes the forward and reverse gear conversion of the upper voltage regulating coil 3 by contacting the first upper switch contact 302 or the second upper switch contact 303. Similarly, the lead-out line at the head end of the lower voltage regulating coil 4 is connected to the first lower switch contact 402, and the lead-out line at the tail end is connected to the second lower switch contact 403. The second adjustment switch 902 corresponding to the lower voltage regulating coil 4 realizes the forward and reverse gear conversion of the lower voltage regulating coil 4 by contacting the first lower switch contact 402 or the second upper switch contact 303.

[0030] like Figure 2 As shown, when the first regulating switch 903 and the second regulating switch 902 are in contact with the first upper switch contact 302 and the first lower switch contact 402 respectively, the upper voltage regulating coil 3 and the lower voltage regulating coil 4 are both connected in the forward direction starting from the head end, and when the first regulating switch 903 and the second regulating switch 902 are in contact with the second upper switch contact 303 and the second lower switch contact 403 respectively, the upper voltage regulating coil 3 and the lower voltage regulating coil 4 are both connected in the reverse direction starting from the tail end, so that the switch body 9 of the utility model can firstly realize the forward and reverse gear combination adjustment of the upper voltage regulating coil 3 and the lower voltage regulating coil 4, and then adjust the movement of the moving contact 901 to realize the access adjustment of different voltage regulating units, so that 16 forward gears, 1 middle gear, and 16 reverse gears can be realized, and a total of 33 gears of output of different voltage values ​​can be realized.

[0031] The working principle of the utility model is:

[0032] An application example is listed below to illustrate the working principle and technical effect of the utility model.

[0033] like Figures 2 to 10As shown, the intermediate transformer structure of this application example includes an iron core 11, an upper high-voltage coil 1, a lower high-voltage coil 2, an upper voltage regulating coil 3, a lower voltage regulating coil 4, an upper low-voltage coil 5 and a lower low-voltage coil 6, wherein the upper high-voltage coil 1 and the lower high-voltage coil 2 form the high-voltage coil group, and the end of the lower high-voltage coil 2 is connected to the regulating connecting line 904.

[0034] like Figure 8 As shown, the structure of the intermediate transformer is specifically as follows: the upper low-voltage coil 5, the upper high-voltage coil 1 and the upper voltage regulating coil 3 are sequentially arranged on the upper outer side of the core corresponding to the core 11 from the inside to the outside, and the lower low-voltage coil 6, the lower high-voltage coil 2 and the lower voltage regulating coil 4 are sequentially arranged on the lower outer side of the core corresponding to the core 11 from the inside to the outside. Figure 2 As shown, the upper high-voltage coil 1 and the lower high-voltage coil 2 on each core column are converted into series-parallel through the corresponding high-voltage series-parallel voltage regulating switch 7, and the upper low-voltage coil 5 and the lower low-voltage coil 6 on each core column are converted into series-parallel through the corresponding low-voltage series-parallel voltage regulating switch 8.

[0035] like Figure 3 and Figure 6 As shown, the high-voltage series-parallel voltage regulating switch 7 includes a high-voltage upper contact 701 and a high-voltage lower contact 702, wherein the a1 contact on the high-voltage series-parallel voltage regulating switch 7 is connected to the head end of the upper high-voltage coil 1 through a connection line, the a2 contact is connected to the head end of the lower high-voltage coil 2 through a connection line, the a3 contact is connected to the end of the upper high-voltage coil 1 through a connection line, and the a3 contact is connected to the a4 contact through a first connection line 703, the a5 contact is connected to the end of the lower high-voltage coil 2 through a connection line, and the a6 contact is empty. The high-voltage upper contact 701 is in contact with the a1, a2, and a3 contacts, and the high-voltage lower contact 702 is in contact with the a4, a5, and a6 contacts. Figure 3 As shown, when the two contact ends of the high-voltage upper contact 701 are in contact with a1 and a2, and the two contact ends of the high-voltage lower contact 702 are in contact with a4 and a5, the upper high-voltage coil 1 and the lower high-voltage coil 2 are connected in parallel. Figure 6 As shown, when the two contact ends of the high-voltage upper contact 701 are in contact with a2 and a3, and the two contact ends of the high-voltage lower contact 702 are in contact with a5 and a6, the upper high-voltage coil 1 is connected in series with the lower high-voltage coil 2. In this application example, the upper high-voltage coil 1 and the lower high-voltage coil 2 are both continuously wound and have the same winding direction, and both the upper and lower windings are left windings.

[0036] like Figure 4 and Figure 7As shown, the low-voltage series-parallel voltage regulating switch 8 includes a low-voltage upper contact 801 and a low-voltage lower contact 802, wherein the b1 contact on the low-voltage series-parallel voltage regulating switch 8 is connected to the head end of the upper low-voltage coil 5 through a connection line, the b2 contact is connected to the head end of the lower low-voltage coil 6 through a connection line, the b3 contact is connected to the end of the upper low-voltage coil 5 through a connection line, and the b3 contact is connected to the b4 contact through a second connection line 803, the b5 contact is connected to the end of the lower low-voltage coil 6 through a connection line, and the b6 contact is empty. The low-voltage upper contact 801 is in contact with the b1, b2, and b3 contacts, and the low-voltage lower contact 802 is in contact with the b4, b5, and b6 contacts. Figure 4 As shown, when the two contact ends of the low-voltage upper contact 801 are in contact with b1 and b2, and the two contact ends of the low-voltage lower contact 802 are in contact with b4 and b5, the upper low-voltage coil 5 and the lower low-voltage coil 6 are connected in parallel. Figure 7 As shown, when the two contact ends of the low-voltage upper contact 801 are in contact with b2 and b3, and the two contact ends of the low-voltage lower contact 802 are in contact with b5 and b6, the upper low-voltage coil 5 is connected in series with the lower low-voltage coil 6. In this application example, the upper low-voltage coil 5 and the lower low-voltage coil 6 are U-shaped spirally wound and wound in opposite directions, wherein the upper low-voltage coil 5 is wound in the right direction and the lower low-voltage coil 6 is wound in the left direction.

[0037] In addition, Figure 8 As shown, a ground screen 12 is provided between the upper low-voltage coil 5, the lower low-voltage coil 6 and the upper high-voltage coil 1, the lower high-voltage coil 2, and the ground screen 12 is grounded through a grounding terminal on the transformer.

[0038] like Figures 9-10 The core 11 is a three-phase five-column structure, wherein the three columns in the middle of the core 11 are core columns, and each coil is respectively arranged according to Figure 8 The arrangement structures shown are wound on the corresponding core columns, with side columns on both sides. Fig. 9 As shown, the high-voltage series-parallel voltage regulating switch 7, the low-voltage series-parallel voltage regulating switch 8 and the switch body 9 of the utility model are all arranged in the oil tank 13 of the transformer, and the regulating moving contact 901 in the switch body 9, the high-voltage upper contact 701 and the high-voltage lower contact 702 in the high-voltage series-parallel voltage regulating switch, and the low-voltage upper contact 801 and the low-voltage lower contact 802 in the low-voltage series-parallel voltage regulating switch 8 can all be controlled by an electric control mechanism to lift and lower to achieve regulation conversion. This is a well-known technology in the art. For example, CN201498344U, CN1905094B and other mechanisms or other mature commercially available products can be used. The high-voltage upper contact 701 and the high-voltage lower contact 702 and the low-voltage upper contact 801 and the low-voltage lower contact 802 are all synchronously lifted and lowered to achieve series-parallel conversion. In addition, a mounting bracket is provided in the oil tank 13 for fixing each switch, and each coil body is arranged according to Figure 8 The structure is arranged as shown, and the corresponding wire end of each coil is led to the corresponding mounting bracket and connected to the corresponding contact on the corresponding switch. The electric control mechanism is also arranged on the corresponding mounting bracket to achieve the purpose of driving the corresponding contact to move up and down.

[0039] The specific control process of this application example is as follows:

[0040] Step 1: According to actual needs, the series-parallel state of the upper low-voltage coil 5 and the lower low-voltage coil 6 is adjusted by the low-voltage series-parallel voltage regulating switch 8 to obtain the required low-voltage side input voltage value;

[0041] Step 2: According to actual needs, adjust the positive and negative gear positions of the upper voltage regulating coil 3 and the lower voltage regulating coil 4 through the adjustment switch on the switch body 9;

[0042] Step 3: According to actual needs, the series-parallel state of the upper high-voltage coil 1 and the lower high-voltage coil 2 is adjusted by the high-voltage series-parallel voltage regulating switch 7;

[0043] Step 4: Finally, the required number of turns and voltage of the access coil are obtained by controlling the movement of the adjusting movable contact 901 on the switch body 9.

[0044] The switch body 9 of the utility model includes ±16 gears, and the upper voltage regulating coil 3 and the lower voltage regulating coil 4 can realize forward and reverse gear combination adjustment through two adjustment switches in the switch body 9, and then the adjustment moving contact 901 in the switch body 9 can be moved to realize the access adjustment of different voltage regulating units, so that 16 forward gears, 1 middle gear, and 16 reverse gears can be achieved, totaling 33 gears of output of different voltage values, and the upper high-voltage coil 1 and the lower high-voltage coil 2 can realize series-parallel conversion adjustment through the corresponding high-voltage series-parallel voltage regulating switch 7, so that 66 gears (33 gears in series and 33 gears in parallel) of different voltage outputs can be further realized.

[0045] For example, when the high-voltage series-parallel voltage regulating switches 7 are operated in parallel, the switch bodies 9 are all in the "reverse" gear and the fine adjustment gear is 17, the output voltage is the lowest 5.324kV, and when the high-voltage series-parallel voltage regulating switches 7 are operated in series, the switch bodies 9 are all in the "positive" gear and the fine adjustment gear is 1, the output voltage is the highest 306.522kV. In addition, when the low-voltage series-parallel voltage regulating switches 8 are in parallel, the input voltage is 5.5kV, and when the low-voltage series-parallel voltage regulating switches 8 are in series, the input voltage is 11kV.

[0046] Therefore, in summary, the low-voltage side of the intermediate transformer in this application example can be connected to two input voltages of 5.5kV or 11kV, and due to the use of the switch structure of the utility model, each input voltage has 33 different voltage outputs, and combined with the series-to-parallel conversion of the upper high-voltage coil 1 and the lower high-voltage coil 2, it can further achieve 66 voltage outputs, ranging from 5.324 to 306.522kV, which can meet the applicable range of more frequencies, with a frequency of 50 to 200Hz and a partial discharge of less than 30pC. At the same time, since the voltage level of the intermediate transformer is high enough and can be adjusted over the entire range, it can be compatible with existing electrical equipment and meet the test requirements of new electrical equipment.

Claims

1. A neutral point positive and negative adjustment system for an ultra-high voltage full-range voltage regulating intermediate transformer, characterized in that: The invention comprises an upper voltage regulating coil (3), a lower voltage regulating coil (4) and a switch body (9), wherein the switch body (9) comprises an adjusting connection line (904), an adjusting movable contact (901) and two adjusting switches, the adjusting connection line (904) is connected to the end of the high-voltage coil group on the corresponding core column of the transformer, and the two ends of the adjusting connection line (904) are respectively connected to the adjusting switches on the corresponding side, the upper voltage regulating coil (3) and the lower voltage regulating coil (4) are respectively controlled to switch between forward and reverse gears through the adjusting switches on the corresponding sides, the upper voltage regulating coil (3) is provided with a plurality of upper voltage regulating static contacts (301), the lower voltage regulating coil (4) is provided with a plurality of lower voltage regulating static contacts (401), and one end of the adjusting movable contact (901) is in contact with the corresponding upper voltage regulating static contact (301), and the other end is in contact with the corresponding lower voltage regulating static contact (401), and each adjusting movable contact (901) is connected to a neutral point connection line (10).

2. The neutral point positive and negative adjustment system for the ultra-high voltage full-range voltage regulation intermediate transformer according to claim 1 is characterized in that: The lead-out connection line of the head end of the upper voltage regulating coil (3) is connected to the first upper switch contact (302), and the lead-out connection line of the tail end is connected to the second upper switch contact (303); a first regulating switch (903) is provided at one end of the regulating connection line (904); and when the first regulating switch (903) contacts the first upper switch contact (302), the upper voltage regulating coil (3) is connected in the forward direction; and when the first regulating switch (903) contacts the second upper switch contact (303), the upper voltage regulating coil (3) is connected in the reverse direction.

3. The neutral point positive and negative adjustment system for the ultra-high voltage full-range voltage regulation intermediate transformer according to claim 1 is characterized in that: The lead-out connection line at the head end of the lower voltage regulating coil (4) is connected to the first lower switch contact (402), and the lead-out connection line at the tail end is connected to the second lower switch contact (403); a second regulating switch (902) is provided at one end of the regulating connection line (904); and when the second regulating switch (902) contacts the first lower switch contact (402), the lower voltage regulating coil (4) is connected in the forward direction; and when the second regulating switch (902) contacts the second lower switch contact (403), the lower voltage regulating coil (4) is connected in the reverse direction.

4. The neutral point positive and negative adjustment system for the ultra-high voltage full-range voltage regulation intermediate transformer according to claim 1 is characterized in that: The high-voltage coil group comprises an upper high-voltage coil (1) and a lower high-voltage coil (2), and the end of the lower high-voltage coil (2) is connected to the adjustment connection line (904).

5. The neutral point positive and negative regulation system for the ultra-high voltage full-range voltage regulation intermediate transformer according to claim 4 is characterized in that: The upper high-voltage coil (1) and the lower high-voltage coil (2) are controlled to be serially connected to parallel by corresponding high-voltage serially connected to parallel voltage regulating switches (7).

6. The neutral point positive and negative regulation system for the ultra-high voltage full-range voltage regulation intermediate transformer according to claim 5 is characterized in that: The high-voltage series-parallel voltage regulating switch (7) comprises a high-voltage upper contact (701) and a high-voltage lower contact (702), wherein the a1 contact on the high-voltage series-parallel voltage regulating switch (7) is connected to the head end of the upper high-voltage coil (1) through a connection line, the a2 contact is connected to the head end of the lower high-voltage coil (2) through a connection line, the a3 contact is connected to the end of the upper high-voltage coil (1) through a connection line, and the a3 contact is connected to the a4 contact through a first connection line (703), the a5 contact is connected to the end of the lower high-voltage coil (2) through a connection line, and the a6 contact is vacant. The high-voltage upper contact (701) is in contact with the a1, a2, and a3 contacts, and the high-voltage lower contact (702) is in contact with the a4, a5, and a6 contacts.

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