No-load voltage regulating transformer and prefabricated substation
By extending the high-voltage tap changer from the low-voltage side in the no-load tap changer and optimizing the arrangement of bushings and clamps, the problem of excessive tank size was solved, achieving miniaturization and cost reduction of the transformer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2026-03-24
AI Technical Summary
Existing no-load tap-changing transformers have increased tank size due to the high-voltage tap leads being located on the high-voltage side, which cannot meet the requirements for transformer miniaturization design.
The high-voltage tap line is led out from the low-voltage side. Combined with the optimized arrangement of bushings and clamps, the space occupied in the high-voltage side and the height direction of the oil tank is reduced. Short leads and centralized arrangement structure are adopted.
This approach reduces the size of the transformer tank, lowers its height and material costs, while simultaneously improving space utilization and mechanical strength.
Smart Images
Figure CN224036197U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of substation technology, and in particular to an off-load tap-changing transformer and a prefabricated substation. Background Technology
[0002] A no-load tap-changing transformer is a type of transformer that changes the voltage ratio by adjusting the tap changer position after the power supply is disconnected. Its characteristic is that the voltage regulation operation is completed under no-load conditions, making it suitable for scenarios where voltage stability requirements are low and frequent voltage regulation is not required.
[0003] In related technologies, no-load tap-changing transformers use a disc switch 01, which is installed on the top cover of the no-load tap-changing transformer. The three-phase high-voltage tap leads 02 of the no-load tap-changing transformer are arranged on the high-voltage side of the transformer. The voltage level on the high-voltage side is high, and the electrical safety distance between the three-phase high-voltage tap leads 02 and the three-phase coils 03 and the tank wall is large. The three-phase high-voltage tap leads 02 need to be extended, which occupies a large amount of internal space in the tank. Consequently, the volume of the transformer tank increases, which cannot meet the design requirements for miniaturization of transformer products. Utility Model Content
[0004] This application proposes a no-load tap-changing transformer to reduce the size of the transformer tank and meet the design requirements for miniaturization of transformer products. This application also proposes a prefabricated substation.
[0005] The no-load tap-changing transformer provided in this application includes a transformer body, which comprises three-phase coils, an upper clamp, a lower clamp, and a no-load tap changer.
[0006] The upper clamp and the lower clamp are located at the upper and lower ends of the coil, respectively, and the no-load tap changer is mounted on the lower clamp.
[0007] The high-voltage tap lead of each coil is led out from the lower end of the low-voltage side of the coil to the lower clamp, and the high-voltage tap lead is connected to the no-load tap changer.
[0008] Preferably, in the above-mentioned no-load tap-changing transformer, a bushing is provided on the low-voltage side of the transformer body near the coil, and the bushing is located in the middle or lower part of the transformer body.
[0009] The bushing corresponds one-to-one with the three-phase coils.
[0010] Preferably, in the above-mentioned no-load tap-changing transformer, the three bushings are arranged at the same height.
[0011] Preferably, in the above-mentioned no-load tap changer transformer, the lower clamp is a U-shaped plate, the closed end of the U-shaped plate is fitted with the transformer body, and the open end of the U-shaped plate is equipped with the no-load tap changer.
[0012] Preferably, in the above-mentioned no-load tap changer, the open end of the U-shaped plate is provided with at least two supports, and the at least two supports are arranged along the length direction of the U-shaped plate. The no-load tap changer is installed on the supports.
[0013] The bracket includes a fixed plate and a connecting plate. The fixed plate is connected to the open end of the U-shaped plate. The connecting plate is L-shaped and has a first connecting plate and a second connecting plate. The first connecting plate is parallel to and connected to the fixed plate. The free end of the second connecting plate is connected to the no-load tap changer. The free end of the second connecting plate has an elongated hole for the remote control line of the controller of the no-load tap changer to pass through.
[0014] Preferably, in the above-mentioned no-load tap-changing transformer, the bracket is welded to the lower clamp.
[0015] Preferably, in the above-mentioned no-load tap-changing transformer, two adjacent lower clamps are connected by a tensioning screw.
[0016] Preferably, in the above-mentioned no-load tap-changing transformer, the upper clamp and the lower clamp are connected by a tensioning screw.
[0017] A prefabricated substation includes an off-load tap-changing transformer, wherein the off-load tap-changing transformer is the off-load tap-changing transformer described in any of the above schemes.
[0018] Preferably, in the above-mentioned prefabricated substation, the low-voltage room and the high-voltage room of the prefabricated substation are arranged side by side on the low-voltage side of the no-load tap-changing transformer.
[0019] This application also discloses a no-load tap-changing transformer, including a transformer body comprising three-phase coils, an upper clamp, a lower clamp, and a no-load tap changer. In this no-load tap-changing transformer, the high-voltage tap leads of each coil are led out from the lower end of the low-voltage side of their respective coil to the lower clamp. That is, the high-voltage tap leads are led out from the low-voltage side of the no-load tap-changing transformer. In related technologies, the upper part of the low-voltage side of the no-load tap-changing transformer has copper busbars for low-voltage leads, and there is a large space below these copper busbars. This solution utilizes this space to arrange the high-voltage tap leads. Compared to related technologies where the high-voltage tap leads are arranged on the high-voltage side, this reduces the space required for arranging the high-voltage tap leads on the high-voltage side, and also reduces the space occupied in the height direction of the oil tank, thus lowering the tank height. This solution reduces the volume of the transformer tank in both the low-voltage-to-high-voltage direction and the height direction, meeting the design requirements for transformer miniaturization.
[0020] This solution also discloses a prefabricated substation, including a no-load tap-changing transformer, which is the no-load tap-changing transformer described in any of the above solutions. Since the no-load tap-changing transformer has the aforementioned technical effects, the prefabricated substation with this no-load tap-changing transformer also has the same technical effects, and will not be elaborated further here. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort, and this application can be applied to other similar scenarios based on the provided drawings. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.
[0022] Figure 1 This is a schematic diagram of the structure of an existing no-load tap-changing transformer;
[0023] Figure 2 This is a schematic diagram of the no-load tap-changing transformer disclosed in the embodiments of this application;
[0024] Figure 3 This is a front view of the no-load tap-changing transformer disclosed in the embodiments of this application;
[0025] Figure 4 This is a layout diagram of the prefabricated substation disclosed in the embodiments of this application.
[0026] in:
[0027] 01-Panel switch; 02-High voltage tap lead; 03-Coil;
[0028] 1-Coil; 2-Upper clamp; 3-Lower clamp; 4-No-load tap changer; 5-High voltage tap lead; 6-Busket; 7-Bracket; 8-Low voltage compartment; 9-High voltage compartment; 10-No-load tap changer; 11-Phase wire; 12-Copper busbar for low voltage lead. Detailed Implementation
[0029] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. The described embodiments are only a part of the embodiments of the present application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are within the scope of protection of the present application.
[0030] It should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0031] It should be understood that the terms "system," "apparatus," "unit," and / or "module" used in this application are a method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.
[0032] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.
[0033] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more.
[0034] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
[0035] like Figure 1 As shown, the low-voltage lead copper busbar 12 is located at the upper part of the low-voltage side. The low-voltage side of the no-load tap changer 10 needs to reserve space for the installation of the low-voltage lead copper busbar 12. However, the low-voltage lead copper busbar 12 only occupies the upper space of the reserved space, and the lower space of the low-voltage side of the no-load tap changer 10 is not utilized. At the same time, the high-voltage tap lead 5 occupies the space of the high-voltage side of the no-load tap changer 10 and the space at the upper end of the coil of the no-load tap changer 10.
[0036] Please see Figure 2 and Figure 3As shown, this application discloses a no-load tap changer transformer, including a transformer body, which includes a three-phase coil 1, an upper clamp 2, a lower clamp 3, and a no-load tap changer 4.
[0037] The phase lines 11 of the three-phase coil 1 are phase A, phase B, and phase C, respectively. The high-voltage tap lead 5 of each coil 1 is led out from the lower end of the low-voltage side of the coil 1 to the lower clamp 3, and the high-voltage tap lead 5 is connected to the no-load tap changer 4. Specifically, the high-voltage tap lead 5 of the phase A coil is named the phase A high-voltage tap lead, the high-voltage tap lead 5 of the phase B coil is named the phase B high-voltage tap lead, and the high-voltage tap lead 5 of the phase C coil is named the phase C high-voltage tap lead. The phase A high-voltage tap lead is led out from the lower end of the low-voltage side of the coil 1 to the lower clamp 3 and then connected to the no-load tap changer 4. The phase B high-voltage tap lead is led out from the lower end of the low-voltage side of the coil 1 to the lower clamp 3 and then connected to the no-load tap changer 4. The phase C high-voltage tap lead is led out from the lower end of the low-voltage side of the coil 1 to the lower clamp 3 and then connected to the no-load tap changer 4.
[0038] The upper part of the low-voltage side of the no-load tap-changing transformer has a copper busbar 12 for low-voltage leads. There is a large space below the copper busbar 12. The no-load tap-changing transformer 10 disclosed in this solution leads the high-voltage tap leads 5 of each coil 1 from the lower end of the low-voltage side of their respective coil 1 to the lower clamp 3. This changes the arrangement of the high-voltage tap leads 5, utilizing the inherent space on the low-voltage side, effectively reducing the space required for the high-voltage tap leads 5 on the high-voltage side. It also reduces the space occupied in the vertical direction of the transformer tank, lowering the tank height. This solution reduces the volume of the transformer tank in both the low-voltage-to-high-voltage direction and the vertical direction, meeting the design requirements for transformer miniaturization.
[0039] In related technologies, increasing the height of the transformer tank increases its volume and requires more transformer oil. The off-load tap-changing transformer 10 disclosed in this solution can use short leads, which reduces the height and volume of the transformer tank and the amount of transformer oil required, thereby reducing the cost of the off-load tap-changing transformer 10.
[0040] Meanwhile, increasing the height of the transformer tank increases its volume, requires more steel, and raises its material cost. The no-load tap-changing transformer 10 disclosed in this solution can use short leads, which allows for a reduction in the height of the transformer tank, a reduction in the amount of steel used, and a lower material cost.
[0041] The no-load tap-changing transformer 10 has an upper clamp 2 and a lower clamp 3. The upper clamp 2 and the lower clamp 3 cooperate to fix the iron core and coil 1, preventing the iron core and coil 1 from moving or vibrating during the operation of the no-load tap-changing transformer 10. There is insulating material between the upper clamp 2 and the lower clamp 3 and the iron core to ensure electrical insulation. The lower clamp 3 also serves to support the internal structure of the entire no-load tap-changing transformer 10, ensuring that the transformer remains stable during operation.
[0042] like Figure 2 The diagram shows a schematic of the structure of a no-load tap-changing transformer 10. A bushing 6 is installed on the low-voltage side of the transformer body near the coil 1. The bushing 6 is located in the middle or lower part of the transformer body.
[0043] Specifically, the bushings 6 corresponding to the three-phase coil 1 are A-phase bushing 6, B-phase bushing 6 and C-phase bushing 6. The A-phase line is led out from the low-voltage side of the A-phase coil and connected to the A-phase bushing 6. The B-phase line is led out from the low-voltage side of the B-phase coil and connected to the B-phase bushing 6. The C-phase line is led out from the low-voltage side of the C-phase coil and connected to the C-phase bushing 6.
[0044] This scheme places the bushing 6 in the middle or lower part of the transformer body, changing the direction of the bushing. At the same time, the bushing 6, the high-voltage tap lead 5 and the no-load tap changer 4 are all concentrated in the middle and lower part of the transformer body, reducing the space occupied in the upper part of the transformer body. On the one hand, this can reduce the volume of the transformer body, and on the other hand, it can improve the space utilization of the no-load tap changer 10.
[0045] The no-load tap-changing transformer 10 disclosed in this scheme has the high-voltage tap lead 5, bushing 6 and low-voltage lead copper busbar 12 of the three-phase coil 1 all set on the low-voltage side of the coil 1. The no-load tap changer 4 is installed on the inherent lower clamp 3 of the no-load tap-changing transformer 10. By making full use of the inherent space and inherent structure of the transformer's low-voltage side, the distance from the tank wall of the no-load tap-changing transformer 10 to the high-voltage side of the coil 1 can be greatly reduced and the cavity height of the upper part of the transformer can be compressed. This significantly reduces the volume space of the transformer tank that is increased by the existing high-voltage tap lead 5 and bushing 6 structure to ensure the insulation distance between the high-voltage tap lead 5 and the coil 1 and the tank.
[0046] In addition, the arrangement of the high-voltage tap lead 5 in the body structure of the no-load tap changer 10 makes the lead wiring neat and tidy, without redundant wire clamps, and has good mechanical strength and reliable electrical performance.
[0047] To ensure the support effect of the lower clamp 3 on the internal structure of the no-load tap-changing transformer 10, this design provides U-shaped plates on both sides of the coil 1, with the two U-shaped plates positioned opposite each other, so as to apply a stable and balanced supporting force to the internal structure of the no-load tap-changing transformer 10.
[0048] The lower clamp 3 is a U-shaped plate. The closed end of the U-shaped plate fits against the body of the device, and the open end of the U-shaped plate is equipped with a no-load tap changer 4.
[0049] Optionally, the lower clamp 3 is a bent part, forming a hollow structure. While ensuring the support of the internal structure of the no-load tap-changing transformer 10, the lower clamp 3 is lightweight, thereby reducing the overall weight of the no-load tap-changing transformer 10 and reducing the difficulty of handling the no-load tap-changing transformer 10.
[0050] The shape of the lower clamp 3 is not limited to a U-shaped plate (a U-shaped plate is a cross-section of the lower clamp 3 perpendicular to its own length direction that is U-shaped), but can also be other shapes that can support the internal structure of the no-load tap-changing transformer 10, such as a cube-shaped strip with a rectangular cross-section. The specific design is to be selected by those skilled in the art according to actual needs, and no specific limitation is made here.
[0051] The no-load tap changer 4 can be directly installed on the open end of the lower clamp 3 or inside the lower clamp 3; the no-load tap changer 4 can also be connected to the open end of the U-shaped lower clamp 3 through the bracket 7.
[0052] In the embodiment where the no-load tap changer 4 is connected to the open end of the U-shaped lower clamp 3 via the bracket 7, the number of brackets 7 is at least two, and at least two brackets 7 are arranged along the length direction of the lower clamp 3. The number of brackets 7 is the number of connection points between the no-load tap changer 4 and the lower clamp 3. The more brackets 7 there are, the higher the connection strength between the no-load tap changer 4 and the lower clamp 3.
[0053] The bracket 7 includes a fixed plate and a connecting plate. The fixed plate is connected to the open end of the U-shaped plate. The connecting plate is L-shaped and has a first connecting plate and a second connecting plate. The first connecting plate is parallel to and connected to the fixed plate. Figure 2 As shown, the connecting plate is located on the side of the fixed plate away from the lower clamp. The free end of the second connecting plate is connected to the no-load tap changer 4. The free end of the second connecting plate has an elongated hole for the remote control line of the controller of the no-load tap changer 4 to pass through.
[0054] like Figure 3 As shown in the embodiment where the no-load tap changer 4 is connected to the lower clamp 3 via a bracket 7, the number of brackets 7 in the figure can be four, and the brackets 7 are rectangular. The number of brackets 7 can be four, but is not limited to four; the specific number can be selected by those skilled in the art according to actual needs.
[0055] Optionally, the no-load tap changer 4 in this solution is a remote-controlled no-load tap changer. The voltage regulating device of the remote-controlled no-load tap changer is located on the top cover of the transformer, and the part of the remote-controlled no-load tap changer used to connect the high-voltage tap lead 5 is located in the lower clamp 3. A long slot is provided on the bracket 7 for the remote control line of the voltage regulating device of the no-load tap changer 4 to pass through. After passing through the bracket 7, the remote control line of the no-load tap changer 4 is led to the voltage regulating device on the tank cover of the no-load regulating transformer 10. The long slot not only provides space for the remote control line to pass through but also limits its movement.
[0056] The bracket 7 is fixedly connected to the lower clamp 3. The fixed connection can be made by welding or integral molding.
[0057] Optionally, the bracket 7 and the lower clamp 3 can be made of the same material or different materials. The lower clamp 3 is grounded, and the bracket 7 can be made of insulating material or non-insulating material.
[0058] In some embodiments, two opposing lower clamps 3 are connected by a tension screw to fix the lower clamps 3 in the desired position.
[0059] The upper clamp 2 and the lower clamp 3 are also connected by a tension screw. Specifically, one end of the tension screw is fixed to the upper end face of the upper clamp 2, and the other end of the tension screw is fixed to the lower end face of the lower clamp 3. Figure 3 As shown, the upper clamp 2 and the lower clamp 3 are connected by four parallel and evenly distributed tension screws.
[0060] This solution also discloses a prefabricated substation, including a no-load tap-changing transformer 10, wherein the no-load tap-changing transformer 10 is the no-load tap-changing transformer described in any of the above solutions.
[0061] Since the no-load tap-changing transformer 10 has the above-mentioned technical effects, the prefabricated substation with the no-load tap-changing transformer 10 also has the same technical effects, which will not be elaborated here.
[0062] like Figure 4 The diagram shows the structure of a prefabricated substation. The prefabricated substation includes an off-load tap-changing transformer 10, a low-voltage chamber 8, and a high-voltage chamber 9. The low-voltage chamber 8 and the high-voltage chamber 9 are arranged side by side on the low-voltage side of the off-load tap-changing transformer 10. The high-voltage chamber 9 is used to process and distribute high-voltage power, while the low-voltage chamber 8 is used to distribute and control low-voltage power, and to distribute and manage the low-voltage power output from the off-load tap-changing transformer 10.
[0063] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed, and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. The scope of this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described application concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
Claims
1. An unloaded voltage regulating transformer, characterized in that, The device body comprises three-phase coils (1), upper clamps (2), lower clamps (3) and no-load tap changers (4), The upper clamps (2) and the lower clamps (3) are respectively located at the upper and lower ends of the coils (1), and the no-load tap changer (4) is installed on the lower clamp (3), The high-voltage tap lead (5) of each coil (1) is led out from the lower end of the low-voltage side of the coil (1) to the lower clamp (3), and the high-voltage tap lead (5) is connected with the no-load tap changer (4).
2. The off-load voltage regulating transformer of claim 1, wherein, The device body is provided with a sleeve (6) near the low-voltage side of the coil (1), and the sleeve (6) is located in the middle or lower part of the device body, The sleeve (6) corresponds to the phase line (11) of the three-phase coil (1) one by one.
3. The off-load voltage regulating transformer of claim 2, wherein, Three sleeves (6) are arranged at the same height.
4. The unloaded voltage regulating transformer according to claim 1 or 2, characterized in that, The lower clamp (3) is a U-shaped plate, the closed end of the U-shaped plate is attached to the device body, and the open end of the U-shaped plate is installed with the no-load tap changer (4).
5. The off-load voltage regulating transformer of claim 4, wherein, The open end of the U-shaped plate is provided with at least two supports (7), and at least two supports (7) are arranged along the length direction of the U-shaped plate, and the no-load tap changer (4) is installed on the support (7), The support (7) comprises a fixed plate and a connecting plate, the fixed plate is connected with the open end of the U-shaped plate, the connecting plate is L-shaped and has a first connecting plate and a second connecting plate, the first connecting plate is parallel to and connected with the fixed plate, the free end of the second connecting plate is connected with the no-load tap changer (4), and the free end of the second connecting plate has a long slot for the remote control line of the controller of the no-load tap changer (4) to pass through.
6. The off-load voltage regulating transformer of claim 5, wherein, The support (7) is welded with the lower clamp (3).
7. The off-load voltage regulating transformer of claim 1, wherein, Two adjacent lower clamps (3) are connected by tensioning screws.
8. The off-load voltage regulating transformer of claim 1, wherein, The upper clamp (2) and the lower clamp (3) are connected by tensioning screws.
9. A prepackaged electrical substation, characterized by The device body comprises three-phase coils (1), upper clamps (2), lower clamps (3) and no-load tap changers (4), 10. The prepackaged electrical substation of claim 9, wherein, The upper clamps (2) and the lower clamps (3) are respectively located at the upper and lower ends of the coils (1), and the no-load tap changer (4) is installed on the lower clamp (3), The high-voltage tap lead (5) of each coil (1) is led out from the lower end of the low-voltage side of the coil (1) to the lower clamp (3), and the high-voltage tap lead (5) is connected with the no-load tap changer (4). The device body is provided with a sleeve (6) near the low-voltage side of the coil (1), and the sleeve (6) is located in the middle or lower part of the device body, The sleeve (6) corresponds to the phase line (11) of the three-phase coil (1) one by one. Three sleeves (6) are arranged at the same height. The lower clamp (3) is a U-shaped plate, the closed end of the U-shaped plate is attached to the device body, and the open end of the U-shaped plate is installed with the no-load tap changer (4). The open end of the U-shaped plate is provided with at least two supports (7), at least two supports (7) are arranged along the length direction of the U-shaped plate, and the no-load tap changer (4) is installed on the support (7), The support (7) comprises a fixed plate and a connecting plate, the fixed plate is connected with the open end of the U-shaped plate, the connecting plate is L-shaped and has a first connecting plate and a second connecting plate, the first connecting plate is parallel to and connected with the fixed plate, the free end of the second connecting plate is connected with the no-load tap changer (4), and the free end of the second connecting plate has a long slot for the remote control line of the controller of the no-load tap changer (4) to pass through. The support (7) is welded with the lower clamp (3). Two adjacent lower clamps (3) are connected by tensioning screws. The upper clamp (2) and the lower clamp (3) are connected by tensioning screws. The device body comprises three-phase coils (1), upper clamps (2), lower clamps (3) and no-load tap changers (4), The upper clamps (2) and the lower clamps (3) are respectively located at the upper and lower ends of the coils (1), and the no-load tap changer (4) is installed on the lower clamp (3), The high-voltage tap lead (5) of each coil (1) is led out from the lower end of the low-voltage side of the coil (1) to the lower clamp (3), and the high-voltage tap lead (5) is connected with the no-load tap changer (4). The device body is provided with a sleeve (6) near the low-voltage side of the coil (1), and the sleeve (6) is located in the middle or lower part of the device body, The sleeve (6) corresponds to the phase line (11) of the three-phase coil (1) one by one. Three sleeves (6) are arranged at the same height. The lower clamp (3) is a U-shaped plate, the closed end of the U-shaped plate is attached to the device body, and the open end of the U-shaped plate is installed with the no-load tap changer (4). The open end of the U-shaped plate is provided with at least two supports (7), at least two supports (7) are arranged along the length direction of the U-shaped plate, and the no-load tap changer (4) is installed on the support (7), The support (7) comprises a fixed plate and a connecting plate, the fixed plate is connected with the open end of the U-shaped plate, the connecting plate is L-shaped and has a first connecting plate and a second connecting plate, the first connecting plate is parallel to and connected with the fixed plate, the free end of the second connecting plate is connected with the no-load tap changer (4), and the free end of the second connecting plate has a long slot for the remote control line of the controller of the no-load tap changer (4) to pass through. The support (7) is welded with the lower clamp (3). Two adjacent lower clamps (3) are connected by tensioning screws. The upper clamp (2) and the lower clamp (3) are connected by tensioning screws. The device body comprises three-phase coils (1), upper clamps (2), lower clamps (3) and no-load tap changers (4),