Split transformer

Abstract

The invention discloses a split transformer, which can solve the problem of circulating current caused by asymmetry of magnetic leakage of a voltage regulating coil of the split transformer. The split transformer comprises a first winding, a second winding and a voltage regulating coil. The first winding is split into a first upper half winding and a first lower half winding in the axial direction of the first winding. The second winding is wound on the outer side of the first winding and comprises a second upper half winding and a second lower half winding which are sequentially arranged in the axial direction of the second winding. The voltage regulating coil is wound on the outer side of the second winding and comprises an upper voltage regulating coil and a lower voltage regulating coil which are sequentially arranged in the axial direction of the second winding. The upper voltage regulation coil and the lower voltage regulation coil each comprise n voltage regulation tapping sections, and n is a positive integer larger than 1. The plurality of voltage regulation tapping sections form at least two cross connection pairs; the cross connection pair comprises two voltage regulation tapping sections which are adjacently connected, and in the cross connection pair, one voltage regulation tapping section is located in the upper voltage regulation coil, and the other voltage regulation tapping section is located in the lower voltage regulation coil.

Description

Technical Field

[0001] This invention relates to the field of transformer manufacturing technology, and more particularly to a split transformer. Background Technology

[0002] Due to their multiple operating modes, split-type transformers can meet the system requirements of phased construction and multi-source input in new energy power generation substations, making them the preferred product for main transformers in these substations. With the rapid development of the new energy photovoltaic power generation field, the power generation capacity of a single base can reach over 1000MW. Therefore, the requirements for the capacity and voltage level of the main transformer for power plant step-up are becoming increasingly stringent, leading to the increasing application of large-capacity split-type transformers in the new energy power generation field.

[0003] Split transformers have normal impedance during full-pass operation. When an external short circuit occurs in one of the low-voltage windings, the impedance increases, thereby effectively limiting the transformer short-circuit current. Considering the possible asymmetry in on-site operating conditions and possible short-circuit operating conditions, the semi-pass operation condition must be considered in the product design of split transformers.

[0004] Existing large-capacity split transformers, when operating in a semi-crossing manner, such as Figure 1 As shown, due to the asymmetry of leakage flux, the voltage phase angle difference between the turns of each tap of the internal voltage regulating coil will cause a large circulating current, resulting in increased product losses. In severe cases, it can lead to thermal breakdown of the voltage regulating coil due to overheating, causing a quality accident. The reason is that in the existing technology, the voltage regulating coil generally adopts a structure of two half-voltage regulating coils connected in series or in parallel. When the voltage regulating coil adopts a parallel structure, due to the asymmetry of leakage flux, the induced electromotive force between the tap sections of the two half-voltage regulating coils is different during the transformer's half-crossing operation, which will generate circulating current within the tap section. When the two half-voltage regulating coils adopt a series structure, the leakage flux will also cause circulating current between the tap sections. When the voltage regulating switch is at the extreme tap position, the circulating current is more serious. The superposition of the operating current and the circulating current may cause local overheating of the voltage regulating coil, leading to insulation thermal breakdown and causing a product quality accident.

[0005] As transformer capacity increases, leakage flux increases accordingly, and the aforementioned circulating current problem becomes more and more serious, which has become a technical challenge in the industry. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a split transformer that can reduce the circulating current problem caused by the asymmetry of leakage flux in the voltage regulating coil of the split transformer.

[0007] This invention provides a split transformer, comprising a first winding, a second winding, and a voltage regulating coil. The first winding is split axially into a first upper winding and a first lower winding. The second winding is wound outside the first winding and includes a second upper winding and a second lower winding arranged sequentially along its axial direction, connected in parallel. The voltage regulating coil is wound outside the second winding and includes an upper voltage regulating coil and a lower voltage regulating coil arranged sequentially along its axial direction; both the upper and lower voltage regulating coils include n voltage regulating taps, where n is a positive integer greater than 1; all voltage regulating taps are connected in series, and the taps of the voltage regulating taps are all led out to a voltage regulating switch. Multiple voltage regulating taps form at least two cross-connection pairs; a cross-connection pair includes two adjacent voltage regulating taps, and in the cross-connection pair, one voltage regulating tap is located in the upper voltage regulating coil, and the other voltage regulating tap is located in the lower voltage regulating coil.

[0008] In some embodiments, in any two adjacent voltage regulating taps, one voltage regulating tap is located in the upper voltage regulating coil, and the other voltage regulating tap is located in the lower voltage regulating coil.

[0009] In some embodiments, among the plurality of voltage regulating taps, at least two adjacent connected voltage regulating taps are located in the upper voltage regulating coil, and / or, at least two adjacent connected voltage regulating taps are located in the lower voltage regulating coil.

[0010] In some embodiments, in a plurality of voltage regulating tap sections, the projected positions of any two adjacent taps in the horizontal plane are staggered.

[0011] In some embodiments, insulating plates are provided on both the upper and lower sides of any tap joint, and the insulating plates extend out of the corresponding tap joint along the circumference of the voltage regulating coil.

[0012] In some embodiments, a central insulating element is provided between the upper voltage regulating coil and the lower voltage regulating coil.

[0013] In some embodiments, insulating end rings are provided at both ends of the upper voltage regulating coil and both ends of the lower voltage regulating coil.

[0014] In some embodiments, the upper voltage regulating coil is wound in a spiral or continuous manner, and the lower voltage regulating coil is wound in a spiral or continuous manner.

[0015] In some embodiments, the voltage regulating tap section is formed by winding one or more wires.

[0016] In some embodiments, the first winding is a low-voltage winding. The second winding is a high-voltage winding. The beginning ends of the second upper half winding and the second lower half winding are both led out from the middle of the second winding and connected to form a high-voltage beginning end. The end ends of the second upper half winding and the second lower half winding are both led out from the two ends of the second winding and connected respectively. In the upper and lower voltage regulating coils, the voltage regulating tap section closest to the high-voltage beginning end is located in the middle of all the voltage regulating tap sections connected in series.

[0017] In the split transformer provided in this embodiment of the invention, by setting a first winding, a second winding, and a voltage regulating coil, the first winding is split into a first upper half winding and a first lower half winding along its axial direction. The second winding is wound outside the first winding and includes a second upper half winding and a second lower half winding arranged sequentially along its axial direction. The second upper half winding and the second lower half winding are connected in parallel, allowing the split transformer to switch between full-pass operation and half-pass operation. By making the voltage regulating coil include an upper voltage regulating coil and a lower voltage regulating coil arranged sequentially along its axial direction, and both the upper and lower voltage regulating coils include n voltage regulating taps, where n is a positive integer greater than 1, all voltage regulating taps are connected in series, and the taps of the voltage regulating taps are all led out to a voltage regulating switch, which can be used to regulate the operating voltage of the split transformer. By forming at least two cross-connection pairs among multiple voltage regulating taps, each cross-connection pair includes two adjacent voltage regulating taps, with one tap located in the upper voltage regulating coil and the other in the lower voltage regulating coil, the number of taps in the voltage regulating branch can be reduced during the semi-cross-operation of the split transformer. This reduces the spatial position of all voltage regulating taps in the leakage magnetic field, and consequently reduces the maximum induced electromotive force difference on each voltage regulating tap. Therefore, the circulating current between the voltage regulating taps can be effectively reduced, thereby reducing the heat generation and losses on the voltage regulating coil. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of this invention, the accompanying drawings used in some embodiments of this invention will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this invention, and those skilled in the art can obtain other drawings based on these drawings. Furthermore, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this invention.

[0019] Figure 1 A schematic diagram of leakage flux during operation of a split transformer; Figure 2 A structural diagram of a split-type transformer provided in an embodiment of the present invention; Figure 3 A wiring diagram of a voltage regulating coil provided in an embodiment of the present invention; Figure 4 for Figure 3 A magnified view of a portion of region Q1; Figure 5 A structural diagram of a voltage regulating coil provided in an embodiment of the present invention; Figure 6 for Figure 3 A magnified view of the Q2 region.

[0020] Wherein, 10-first winding; 20-second winding; 30-voltage regulating coil; 40-voltage regulating tap section; 50-insulating plate; 60-high voltage start end; 70-voltage regulating switch; 80-pressure ring; 90-middle insulating component; 100-insulating end ring; HT1-upper voltage regulating coil; HT2-lower voltage regulating coil; LV1-first upper half winding; LV2-first lower half winding; HV1-second upper half winding; HV2-second lower half winding. Detailed Implementation

[0021] The technical solutions in some embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided by the present invention are within the scope of protection of the present invention.

[0022] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0023] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0024] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." Furthermore, the specific features, structures, materials, or characteristics described may be included in any suitable manner in any one or more embodiments or examples.

[0025] In describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. The embodiments of the invention described herein are not necessarily limited to the content of this document.

[0026] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0027] Example 1: like Figure 2 As shown, an embodiment of the present invention provides a split transformer, which is applied in a transmission line for voltage regulation.

[0028] like Figure 2 and Figure 3 As shown, the split transformer includes a first winding 10, a second winding 20, and a voltage regulating coil 30. The first winding 10 is split along its axial direction into a first upper winding LV1 and a first lower winding LV2. The second winding 20 is wound outside the first winding 10 and includes a second upper winding HV1 and a second lower winding HV2 arranged sequentially along its axial direction. The second upper winding HV1 and the second lower winding HV2 are connected in parallel. The voltage regulating coil 30 is wound outside the second winding 20 and includes an upper voltage regulating coil HT1 and a lower voltage regulating coil HT2 arranged sequentially along its axial direction. Both the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2 include n voltage regulating taps 40, where n is a positive integer greater than 1. All the voltage regulating taps 40 are connected in series, and the taps of the voltage regulating taps 40 are all led out to the voltage regulating switch 70. Multiple voltage regulating taps 40 form at least two cross-connection pairs; a cross-connection pair includes two adjacent voltage regulating taps 40, and in the cross-connection pair, one voltage regulating tap 40 is located in the upper voltage regulating coil HT1, and the other voltage regulating tap 40 is located in the lower voltage regulating coil HT2.

[0029] For example, the first winding 10 can be a low-voltage winding, and the second winding 20 can be a high-voltage winding. Pressure rings 80 are provided at the upper and lower ends of the first winding 10 and the second winding 20.

[0030] For example, in the first winding 10, the first upper half winding LV1 and the first lower half winding LV2 can operate independently.

[0031] For example, in combination Figure 3 In the second winding 20, the second upper half winding HV1 and the second lower half winding HV2 are connected in parallel and then connected to the voltage regulating coil 30.

[0032] For example, in the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2, the voltage regulating taps 40 can be two, three, or four, etc. Combined with... Figure 3 and Figure 4In this embodiment, the number of voltage regulating taps 40 in both the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2 is four, as an example for illustration. At this time, as... Figure 4 As shown, the voltage regulating coil 30 includes a total of eight voltage regulating tap sections 40.

[0033] For example, such as Figure 4 As shown, eight voltage regulating taps 40 are connected in series. Along the series connection direction, the eight voltage regulating taps 40 can be labeled as tap 1, tap 2, tap 3, tap 4, tap 5, tap 6, tap 7, and tap 8, respectively. The taps corresponding to tap 1 are labeled as tap 1 and tap 2', tap 2 as tap 2 and tap 3', tap 3 as tap 3 and tap 4', tap 4 as tap 4 and tap 5', tap 5 as tap 5 and tap 6', tap 6 as tap 6 and tap 7', tap 7 as tap 7 and tap 8', and tap 8 as tap 8 and tap 9. For example... Figure 4 As shown, the upper voltage regulating coil HT1 includes tap section 2, tap section 3, tap section 6, and tap section 7; the lower voltage regulating coil HT2 includes tap section 1, tap section 4, tap section 5, and tap section 8.

[0034] The connection method for the eight voltage regulating taps 40 and the voltage regulating switch 70 can be referred to Figure 3 and Figure 4 It should be noted that the markings on the aforementioned tap sections and tap joints are only for distinguishing different tap sections and tap joints, and have no other special meaning; Figure 3 The numerical serial number on the medium-voltage regulating switch 70 is the position mark of the voltage regulating switch and is unrelated to the marking of the tap joint or tap section.

[0035] In this case, the "two adjacent voltage regulating tap sections 40" mentioned above can be tap section 1 and tap section 2, or tap section 4 and tap section 5, etc. That is, tap section 1 and tap section 2 form a cross connection pair, and tap section 4 and tap section 5 form a cross connection pair.

[0036] For example, Figure 4In the cross connection pair formed by tap 1 and tap 2, tap 1 is located in the lower voltage regulating coil HT2, and tap 2 is located in the upper voltage regulating coil HT1; in the cross connection pair formed by tap 3 and tap 4, tap 4 is located in the lower voltage regulating coil HT2, and tap 3 is located in the upper voltage regulating coil HT1; in the cross connection pair formed by tap 5 and tap 6, tap 5 is located in the lower voltage regulating coil HT2, and tap 6 is located in the upper voltage regulating coil HT1; in the cross connection pair formed by tap 7 and tap 8, tap 8 is located in the lower voltage regulating coil HT2, and tap 7 is located in the upper voltage regulating coil HT1.

[0037] At this time, combined Figure 1 , Figure 2 , Figure 3 and Figure 4 When the split transformer is in semi-crossing operation, the voltage regulating coil in the prior art occupies the height of 8 wires along its axial direction, while the voltage regulating coil in the split transformer of this invention occupies the height of 4 wires along its axial direction. This is equivalent to reducing the number of taps in the voltage regulating branch. The spatial position of all voltage regulating taps 40 in the leakage magnetic field is reduced by about 50%. Correspondingly, the maximum induced electromotive force difference on the voltage regulating taps 40 is reduced by about 50%, which can effectively reduce the circulating current between the voltage regulating taps 40, thereby reducing the heat generation and loss on the voltage regulating coil 30.

[0038] Therefore, in the split transformer provided by this embodiment of the invention, by setting a first winding 10, a second winding 20, and a voltage regulating coil 30, the first winding 10 is split along its axial direction into a first upper half winding LV1 and a first lower half winding LV2. The second winding 20 is wound outside the first winding 10 and includes a second upper half winding HV1 and a second lower half winding HV2 arranged sequentially along its axial direction. The second upper half winding HV1 and the second lower half winding HV2 are connected in parallel, so that the split transformer can switch between full-crossing operation and half-crossing operation. By making the voltage regulating coil 30 include an upper voltage regulating coil HT1 and a lower voltage regulating coil HT2 arranged sequentially along its axial direction, and both the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2 include n voltage regulating tap sections 40, where n is a positive integer greater than 1, all the voltage regulating tap sections 40 are connected in series, and the taps of the voltage regulating tap sections 40 are all led out to the voltage regulating switch 70, so that the operating voltage of the split transformer can be regulated by the voltage regulating switch 70. By forming at least two cross-connection pairs of multiple voltage regulating taps 40, each cross-connection pair includes two adjacent voltage regulating taps 40, with one voltage regulating tap 40 located in the upper voltage regulating coil HT1 and the other voltage regulating tap 40 located in the lower voltage regulating coil HT2, the number of taps in the voltage regulating branch can be reduced during the semi-crossing operation of the split transformer. This reduces the spatial position of all voltage regulating taps 40 in the leakage magnetic field, and correspondingly reduces the maximum induced electromotive force difference on each voltage regulating tap 40. Therefore, the circulating current between the voltage regulating taps 40 can be effectively reduced, thereby reducing the heat generation and losses on the voltage regulating coil 30.

[0039] In some embodiments, in any two adjacent voltage regulating taps 40, one voltage regulating tap 40 is located in the upper voltage regulating coil HT1, and the other voltage regulating tap 40 is located in the lower voltage regulating coil HT2.

[0040] For example, the aforementioned tap segments 1, 3, 5, and 7 are located in the lower voltage regulating coil HT2, and tap segments 2, 4, 6, and 8 are located in the upper voltage regulating coil HT1. In this case, it can be understood that, along the series direction, multiple voltage regulating tap segments 40 are arranged alternately on the lower voltage regulating coil HT2 and the upper voltage regulating coil HT1.

[0041] In other embodiments, such as Figure 4 As shown, among the multiple voltage regulating taps 40, at least two adjacent voltage regulating taps 40 are located in the upper voltage regulating coil HT1.

[0042] like Figure 4 As shown, among the multiple voltage regulating taps 40, taps 2 and 3 are simultaneously located in the upper voltage regulating coil HT1, and taps 6 and 7 are simultaneously located in the upper voltage regulating coil HT1.

[0043] This reduces the circulating current between the voltage regulating tap sections 40 and decreases the length of the connecting line between two adjacent voltage regulating tap sections 40.

[0044] In other embodiments, of the plurality of voltage regulating taps 40, at least two adjacently connected voltage regulating taps 40 are located in the lower voltage regulating coil HT2.

[0045] like Figure 4 As shown, among the multiple voltage regulating taps 40, taps 4 and 5 are simultaneously located in the lower voltage regulating coil HT2.

[0046] Similarly, this can reduce the length of the connecting line between two adjacent voltage regulating taps 40 while reducing the circulating current between the taps 40.

[0047] In some embodiments, such as Figure 5 and Figure 6 As shown, in the multiple voltage regulating tap sections 40, the projection positions of any two adjacent taps in the horizontal plane are staggered.

[0048] Figure 6 In the middle, tap joints 4', 8', 7', and 3' are connected sequentially from top to bottom. Figure 6 The left side is offset. Tap joints 6, 2, 3, and 7 are arranged sequentially from top to bottom. Figure 6 The left side is offset.

[0049] By setting up the above, the distance between two adjacent tap joints can be increased, ensuring the electrical strength of each tap joint and forming a good heat dissipation structure, avoiding poor heat dissipation and local overheating caused by thick insulation wrapping and concentrated tap joints.

[0050] In some embodiments, such as Figure 6 As shown, an insulating plate 50 is provided on both the upper and lower sides of any tap joint, and the insulating plate 50 extends out of the corresponding tap joint along the circumference of the voltage regulating coil 30.

[0051] For example, the material of the insulating board 50 may be insulating paper.

[0052] For example, the distance by which the insulating plate 50 extends out of the corresponding tap joint along the circumference of the voltage regulating coil 30 needs to be determined based on factors such as the voltage level of the split transformer. For instance, the distance by which the insulating plate 50 extends out of the corresponding tap joint along the circumference of the voltage regulating coil 30 can be set to be greater than 15mm.

[0053] By installing the insulating plate 50, the electrical insulation level between the tap joints can be increased.

[0054] In some embodiments, such as Figure 5As shown, a middle insulating element 90 is provided between the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2.

[0055] For example, the central insulating element 90 can be an insulating cylinder, etc.

[0056] The above settings can increase the insulation strength between the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2.

[0057] In some embodiments, such as Figure 5 As shown, insulating end rings 100 are provided at both ends of the upper voltage regulating coil HT1 and both ends of the lower voltage regulating coil HT2.

[0058] like Figure 6 As shown, the upper voltage regulating coil HT1 is wound in a spiral or continuous manner, and the lower voltage regulating coil HT2 is wound in a spiral or continuous manner.

[0059] Both spiral and continuous coil winding methods have the advantages of high mechanical strength and good heat dissipation. By adopting the above settings, the mechanical and heat dissipation performance of the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2 can be improved.

[0060] For example, when the upper voltage regulating coil HT1 or the lower voltage regulating coil HT2 is wound in a spiral manner, the corresponding insulating end ring 100 is a slanted end ring with a large and small head structure; when the upper voltage regulating coil HT1 or the lower voltage regulating coil HT2 is wound in a continuous manner, the corresponding insulating end ring 100 is a flat end ring.

[0061] The above settings can improve the insulation strength of the upper and lower ends of the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2.

[0062] In some embodiments, such as Figure 6 As shown, the voltage regulating tap section 40 is formed by winding one or more wires.

[0063] When the voltage regulating tap section 40 is formed by winding a single wire, its structure can be simplified and its cost reduced. When the voltage regulating tap section 40 is formed by winding multiple wires, its current carrying capacity can be improved.

[0064] Understandably, the number of turns of the conductor in the voltage regulating tap 40 needs to be determined based on the performance parameters of the split transformer.

[0065] In some embodiments, such as Figure 2As shown, the first winding 10 is a low-voltage winding; the second winding 20 is a high-voltage winding. The starting ends of the second upper winding HV1 and the second lower winding HV2 are both led out from the middle of the second winding 20 and connected to form a high-voltage starting end 60. The tail ends of the second upper winding HV1 and the second lower winding HV2 are both led out from the two ends of the second winding 20 and connected. Figure 6 Among the upper voltage regulating coil HT1 and the lower voltage regulating coil HT2, the voltage regulating tap 40 closest to the high voltage head end 60 is located in the middle of all the voltage regulating taps 40 connected in series.

[0066] For example, in the first winding 10, both the first upper winding LV1 and the first lower winding LV2 adopt U-shaped structure coils. The beginning and end of the first upper winding LV1 are led out from the same end, and the beginning and end of the first lower winding LV2 are led out from the same end, for example, both are led out from the upper end.

[0067] For example, in Figure 4 In the diagram, all the voltage regulating taps 40 are sequentially labeled as tap 1, tap 2, tap 3, tap 4, tap 5, tap 6, tap 7, and tap 8. At this time, the voltage regulating taps 40 located at the ends of all the interconnected voltage regulating taps 40 are tap 1 and tap 8, while taps 2, 3, 4, 5, 6, and 7 are the voltage regulating taps 40 located in the middle of all the interconnected voltage regulating taps 40.

[0068] The above settings can prevent insufficient electrical insulation between the high-voltage start-up and the voltage regulating coil 30 due to potential oscillation when the voltage regulating switch 70 is in the most negative tap position during the operation of the split transformer.

[0069] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A split transformer, characterized in that, include: The first winding (10) is split along its axis into a first upper half winding (LV1) and a first lower half winding (LV2). The second winding (20), wound outside the first winding (10), includes a second upper half winding (HV1) and a second lower half winding (HV2) arranged sequentially along its axial direction, the second upper half winding (HV1) and the second lower half winding (HV2) being connected in parallel; and, A voltage regulating coil (30) is wound on the outside of the second winding (20) and includes an upper voltage regulating coil (HT1) and a lower voltage regulating coil (HT2) arranged sequentially along its axial direction; both the upper voltage regulating coil (HT1) and the lower voltage regulating coil (HT2) include n voltage regulating taps (40), where n is a positive integer greater than 1; all the voltage regulating taps (40) are connected in series, and the taps of the voltage regulating taps (40) are all led out to the voltage regulating switch (70). The plurality of the voltage regulating taps (40) form at least two cross-connection pairs; the cross-connection pair includes two adjacent voltage regulating taps (40), and in the cross-connection pair, one voltage regulating tap (40) is located in the upper voltage regulating coil (HT1) and the other voltage regulating tap (40) is located in the lower voltage regulating coil (HT2).

2. The split transformer according to claim 1, characterized in that, Of any two adjacent voltage regulating taps (40), one voltage regulating tap (40) is located in the upper voltage regulating coil (HT1), and the other voltage regulating tap (40) is located in the lower voltage regulating coil (HT2).

3. The split transformer according to claim 1, characterized in that, Of the plurality of voltage regulating taps (40), at least two adjacently connected voltage regulating taps (40) are located in the upper voltage regulating coil (HT1), and / or at least two adjacently connected voltage regulating taps (40) are located in the lower voltage regulating coil (HT2).

4. The split transformer according to claim 2 or 3, characterized in that, In the plurality of the voltage regulating tap sections (40), the projection positions of any two adjacent taps in the horizontal plane are staggered.

5. The split transformer according to claim 4, characterized in that, Insulating plates (50) are provided on both the upper and lower sides of any of the tap joints, and the insulating plates (50) extend out of the corresponding tap joints along the circumference of the voltage regulating coil (30).

6. The split transformer according to claim 2 or 3, characterized in that, A central insulating element (90) is provided between the upper voltage regulating coil (HT1) and the lower voltage regulating coil (HT2).

7. The split transformer according to claim 2 or 3, characterized in that, Insulating end rings (100) are provided at both ends of the upper voltage regulating coil (HT1) and both ends of the lower voltage regulating coil (HT2).

8. The split transformer according to claim 2 or 3, characterized in that, The upper voltage regulating coil (HT1) is wound in a spiral or continuous manner, and the lower voltage regulating coil (HT2) is wound in a spiral or continuous manner.

9. The split transformer according to claim 2 or 3, characterized in that, The voltage regulating tap section (40) is formed by winding one or more wires.

10. The split transformer according to claim 2 or 3, characterized in that, The first winding (10) is a low-voltage winding; The second winding (20) is a high-voltage winding. The first end of the second upper half winding (HV1) and the first end of the second lower half winding (HV2) are both led out from the middle of the second winding (20) and connected to form a high-voltage first end (60). The tail end of the second upper half winding (HV1) and the tail end of the second lower half winding (HV2) are both led out from the two ends of the second winding (20) and connected respectively. Of the upper voltage regulating coil (HT1) and the lower voltage regulating coil (HT2), the voltage regulating tap section (40) closest to the high voltage head end (60) is located in the middle of all the voltage regulating tap sections (40) connected in series.

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