Transition resistor for composite on-load tap-changer

Abstract

The utility model discloses a composite transition resistor for an on-load tap-changer, which comprises four layers of mounting frames, a connecting plate I, a connecting plate II, a connecting plate III and a connecting plate IV, three layers of ceramic chips are mounted in each layer of mounting frame, a layer of resistance wire sheet is respectively arranged between two adjacent layers of ceramic chips, and a spring sheet is arranged outside each layer of mounting frame; the upper end and the lower end of the first connecting plate are pressed on the left outer wall of the first-layer mounting frame and the left outer wall of the second-layer mounting frame through fasteners respectively. The upper end and the lower end of the second connecting plate are pressed on the left outer wall of the third-layer mounting frame and the left outer wall of the fourth-layer mounting frame through fasteners respectively. The upper end and the lower end of the third connecting plate are pressed on the right outer wall of the second-layer mounting frame and the right outer wall of the third-layer mounting frame through fasteners respectively. The upper end and the lower end of the fourth connecting plate are pressed on the outer wall of the right side of the first-layer mounting frame and the outer wall of the right side of the fourth-layer mounting frame through fasteners respectively. The fastening device is simple in structure, reliable in fastening and low in cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of on-load tap changers, and in particular relates to a transition resistor for a composite on-load tap changer. Background Art

[0002] There are two main types of transition resistors for existing composite on-load tap-changers: a winding type and a resistor wire sheet superposition type.

[0003] Winding type (its structure is as follows Figure 1 As shown in the figure): The resistance wire is wound on a fixed cylinder, and then the cylinder with the wound resistance wire is mounted on the main shaft of the switch. Specific tooling is required for winding the resistance wire, and the winding time is long and prone to errors. At the same time, the cylinder with the resistance wire is mounted on the main shaft, which is very troublesome to replace. The entire switch core needs to be disassembled before replacement. Due to the particularity of the on-load tap changer, the transition resistor needs to match the transformer parameters. Once the transformer parameters are modified, the transition resistor needs to be changed accordingly. At this time, the transition resistor needs to be replaced.

[0004] Resistor wire sheet superposition type: The required resistance value can be achieved by flexibly superimposing resistor sheets, connecting them in series or in parallel. The assembly method is simple and flexible. The existing resistor wire sheet transition resistor generally includes four layers of mounting frames. Two layers of resistor wire sheets are connected in parallel in each mounting frame. The resistor wire sheets in the four mounting frames are connected in series. The upper and lower sides of the two layers of resistor wire sheets in each mounting frame are separated from the middle by ceramic sheets. At the same time, spring sheets are provided outside the upper and lower ceramic sheets of each mounting frame to clamp and fix the resistor wire sheets. Figure 2 and Figure 3 The figure is a schematic diagram of the structure of the existing resistance wire transition resistor, which has the following shortcomings:

[0005] (1) If Figure 2 and Figure 3As shown, the existing resistance wire transition resistor is locked between the upper and lower insulating mounting plates of the switch core by fasteners. Since the height of the four mounting frames of the transition resistor after stacking is lower than the distance between the upper and lower insulating mounting plates, when designing the transition resistor, in order to improve the stability of the transition resistor after installation, a spacer is provided between the first-layer mounting frame and the second-layer mounting frame of the transition resistor, and between the fourth-layer mounting frame of the transition resistor and the lower insulating mounting plate. In this way, by continuously twisting the fasteners, the distance between the upper and lower insulating mounting plates is reduced, thereby clamping the transition resistor. That is, the fasteners need to continuously resist the tension of the two insulating mounting plates. The setting of the spacer tube reduces the overall stability of the transition resistor. Moreover, during the operation of the composite on-load tap changer, the transition resistor needs to rotate at high speed with the switch core. Under the action of centrifugal force, the distance between the two insulating mounting plates becomes larger, which makes it impossible to effectively clamp the transition resistor, causing the transition resistor to loosen. In addition, the installation part of the fasteners is located on both sides of the waist of the transition resistor. Under high-speed rotation, the loose installation frame will swing. As the swing intensifies, the installation frame will crack, and the scrap rate is high.

[0006] (2) The connection between the two ends of the existing transition resistor wire requires an independent terminal block, which not only increases the material cost, but also the independent terminal block is easily damaged, increasing the maintenance cost.

[0007] (3) Due to the existing transition resistor installation frame structure, only M5 fasteners can be used for fastening. However, on the composite on-load tap changer, the transition resistor needs to rotate at high speed with the core. The M5 fasteners are not strong enough and are easy to loosen. The core needs to be lifted and checked after the switch has been operated for a certain number of times, which increases the operating cost of the transformer. If no inspection is performed, the transition resistor will loosen to a certain extent and burn the switch.

[0008] (4) If Fig. 9 As shown, since the transition resistor is fixed when used on a combined switch, it rotates at high speed with the switch when used on a compound switch, and the connecting pieces at both ends of the resistance wire of the existing transition resistor are easily broken after repeated operation. Utility Model Content

[0009] In order to solve the above problems, the purpose of the utility model is to provide a transition resistor for a composite on-load tap changer which has simple assembly, compact structure, reliable fastening and low cost.

[0010] The purpose of the utility model is achieved through the following technical solutions:

[0011] A transition resistor for a composite on-load tap changer comprises a four-layer installation frame arranged from top to bottom, three layers of ceramic sheets are installed from top to bottom in each layer of the installation frame, a layer of resistance wire sheet is respectively arranged between two adjacent layers of ceramic sheets of each layer of the installation frame, and two spring sheets are arranged outside each layer of the installation frame, the spring sheets are clamped on the outside of the upper and lower layers of ceramic sheets and make the ceramic sheets clamp the resistance wire sheet; it also comprises a connecting plate 1, a connecting plate 2, a connecting plate 3 and a connecting plate 4; wherein the upper and lower ends of the connecting plate 1 are respectively pressed on the left outer wall of the first layer of the installation frame and the left outer wall of the second layer of the installation frame by fasteners; the upper and lower ends of the connecting plate 2 are respectively pressed on the left outer wall of the third layer of the installation frame and the left outer wall of the fourth layer of the installation frame by fasteners; the upper and lower ends of the connecting plate 3 are respectively pressed on the right outer wall of the second layer of the installation frame and the right outer wall of the third layer of the installation frame by fasteners; the upper and lower ends of the connecting plate 4 are respectively pressed on the right outer wall of the first layer of the installation frame and the right outer wall of the fourth layer of the installation frame by fasteners.

[0012] Furthermore, the two layers of resistance wire sheets of each layer of the installation frame are connected in parallel to form a resistance wire group, and the resistance wire groups of the four layers of the installation frame are connected in series in sequence.

[0013] Furthermore, the connecting plate 1, the connecting plate 2, the connecting plate 3 and the connecting plate 4 are all conductive metal plates, which play the role of series resistance wire sheets.

[0014] Furthermore, the left end of the first-layer installation frame resistance wire group and the left end of the second-layer installation frame resistance wire group are respectively pressed one-to-one by fasteners on the two ends of connecting plate one; the left end of the third-layer installation frame resistance wire group and the left end of the fourth-layer installation frame resistance wire group are respectively pressed one-to-one by fasteners on the two ends of connecting plate two; the right end of the second-layer installation frame resistance wire group and the right end of the third-layer installation frame resistance wire group are respectively pressed one-to-one by fasteners on the two ends of connecting plate three; the right end of the first-layer installation frame resistance wire group is pressed by fasteners on the upper end of connecting plate four, the lower end of connecting plate four is bridged with one end of the power supply, and the right end of the fourth-layer installation frame resistance wire group is pressed by fasteners on the outer wall of the fourth-layer installation frame and bridged with the other end of the power supply.

[0015] Furthermore, the connecting plate 1, the connecting plate 2, the connecting plate 3 and the connecting plate 4 are all U-shaped and arranged laterally, wherein the openings of the connecting plate 1 and the connecting plate 2 face left, and the openings of the connecting plate 3 and the connecting plate 4 face right.

[0016] Furthermore, the connecting plates one, two, three, four and the connecting plates at both ends of the resistance wire are all pure copper plates. At the same time, the thickness of the connecting plates at both ends of the resistance wire is 3-6mm. After the material of the connecting plates at both ends of the resistance wire is changed to pure copper, the toughness is increased; at the same time, the connecting plates are widened to increase the strength of the connecting plates.

[0017] Furthermore, the four-layer installation frames are stacked up and down to form a frame body, and the frame body is fixed to an insulating installation plate of the composite on-load tap changer by fasteners vertically passing through two diagonal parts thereof.

[0018] Furthermore, the fasteners used to fix the frame body are M8 fasteners, and M8 bolts have higher strength. The fasteners used to fix the connecting plate 1, the connecting plate 2, the connecting plate 3 and the connecting plate 4 are M5 fasteners.

[0019] Furthermore, a plurality of saw teeth for clamping the resistance wire are respectively arranged on the lower surface of the upper ceramic sheet, the upper and lower surfaces of the middle ceramic sheet, and the lower surface of the lower ceramic sheet.

[0020] Furthermore, heat dissipation grooves for heat dissipation are provided at the upper and lower parts of each layer of the mounting frame.

[0021] The utility model has a simple and compact structure, reliable fastening and low cost. Due to the simple structure, the assembly is flexible and concise; the material of the installation frame of the utility model is injection molding material, which improves product quality and production efficiency. The frame is provided with a resistor wire connection installation hole, and there is no need to install a separate terminal board. The entire transition resistor is fixedly installed by M8 bolts for diagonal fixation, which is reliable; the connection plate close to the outside of the frame not only plays the role of connecting the resistor wire in series, but also plays the role of stabilizing the installation frame, further improving the stability of the structure. The application of this transition resistor prolongs the maintenance cycle of the composite on-load tap changer, improves the overall performance of the composite vacuum switch, reduces the operation and maintenance cost of the transformer, and improves the performance of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0023] Figure 1 It is a structural schematic diagram of an existing wound on-load tap-changer transition resistor;

[0024] Figure 2 It is a top view of an existing resistor wire sheet superimposed on-load tap changer transition resistor;

[0025] Figure 3 for Figure 2 Cross-sectional view along AA direction;

[0026] Figure 4 A three-dimensional diagram of a transition resistor for a composite on-load tap changer according to the utility model;

[0027] Figure 5 It is a stereoscopic diagram of the transition resistor for the composite on-load tap changer of the utility model at another viewing angle;

[0028] Figure 6 It is a top view of the transition resistor for the composite on-load tap changer of the utility model;

[0029] Figure 7 for Figure 6 Cross-sectional view along direction BB;

[0030] Figure 8 It is a top view of the installation frame of the utility model;

[0031] Fig. 9 It is a structural diagram of the resistance wire sheet of the existing transition resistor;

[0032] Fig.10 This is a structural diagram of the resistance wire sheet of the transition resistor of the utility model;

[0033] As shown in the figure: 1-installation frame, 2-resistance wire sheet, 3-heat sink, 4-ceramic sheet, 5-spring sheet, 6-M8 fastener, 7-M5 fastener, 8-insulating mounting plate, 9-connecting plate one, 10-connecting plate two, 11-connecting plate three, 12-connecting plate four, 13-connecting plate. DETAILED DESCRIPTION

[0034] The following is an explanation of the implementation of the present invention by specific specific embodiments. People familiar with the technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that the structures, proportions, sizes, etc. drawn in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the utility model, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the utility model, should still fall within the scope of the technical content disclosed by the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the utility model. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the utility model without substantial change of the technical content.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Example 1

[0037] like Figure 4-7 As shown, this embodiment provides a transition resistor for a composite on-load tap changer, including a four-layer installation frame 1, a connecting plate 1 9, a connecting plate 2 10, a connecting plate 3 11 and a connecting plate 4 12 arranged from top to bottom.

[0038] The four-layer installation frame 1 is overlapped and placed together to form a frame body, and the frame body is fixed to an insulating mounting plate 8 of the composite on-load tap changer by fasteners passing vertically through its two diagonal parts. In this embodiment, the frame body is directly fixed to an insulating mounting plate 8 by fasteners, and the frame body is no longer clamped by tightening two insulating mounting plates with fasteners. The operation is simpler, the fastening is better, and it is more reliable. The fasteners used to fix the frame body are M8 fasteners 6 (including M8 bolts and matching nuts). The bolts of M8 fasteners 6 have higher strength than the M5 fasteners 7 used in the existing transition resistors and are not easy to loosen. In addition, Figure 8 As shown, in this embodiment, the traditional wiring board and the installation frame 1 are integrally injection-molded, which saves installation costs and also greatly improves the stability of the transition resistance.

[0039] Three layers of ceramic sheets 4 are installed from top to bottom in each layer of the installation frame 1 , which are responsible for supporting and positioning the resistance wire sheet 2 .

[0040] A layer of resistance wire sheet 2 is provided between two adjacent layers of ceramic sheets 4 of each installation frame 1. The resistance wire sheet 2 is responsible for bridging during the switching process of the composite on-load tap changer. The two layers of resistance wire sheets 2 of each installation frame 1 are connected in parallel to form a resistance wire group (the two resistance wire sheets 2 in the resistance wire group are connected in parallel through two connecting sheets 13 at both ends), and the resistance wire groups of the four installation frames 1 are connected in series in sequence. Fig.10 As shown, the connecting pieces 13 at both ends of the resistance wire piece 2 are pure copper plates. At the same time, the connecting pieces 13 at both ends of the resistance wire piece 2 (resistance wire group) are 5 mm thick. After the material of the connecting pieces 13 at both ends of the resistance wire piece 2 is changed to pure copper, the toughness is increased; at the same time, the connecting pieces 13 are widened to increase the strength of the connecting pieces 13.

[0041] Two spring sheets 5 are provided outside each layer of the mounting frame 1 , and the spring sheets 5 are clamped tightly around the upper ceramic sheet 4 and the lower ceramic sheet 4 . The spring sheets 5 are responsible for fixing the resistance wire sheet 2 and the ceramic sheet 4 on the mounting frame 1 and making the ceramic sheet 4 clamp the resistance wire sheet 2 .

[0042] The connecting plate 1 9 , the connecting plate 2 10 , the connecting plate 3 11 and the connecting plate 4 12 are all U-shaped and have conductive copper plates arranged laterally. The thickness of the conductive copper plates is greater than 0.3 mm and has a certain bending strength. They play the role of connecting the series resistor wire 2, stabilizing the installation frame 1 and improving the stability of the frame structure. Among them, the openings of the connecting plate 1 9 and the connecting plate 2 10 face left, and the openings of the connecting plate 3 11 and the connecting plate 4 12 face right.

[0043] The upper and lower ends of the connecting plate 9 are respectively pressed against the left outer wall of the first layer installation frame 1 and the left outer wall of the second layer installation frame 1 by fasteners. The left end of the resistance wire group connecting piece 13 of the first layer installation frame 1 and the left end of the resistance wire group connecting piece 13 of the second layer installation frame 1 are respectively pressed against the two ends of the connecting plate 9 by fasteners one by one, that is: Figure 4 As shown, the left end of the resistor wire group connecting piece 13 of the first-layer installation frame 1 overlaps the outside of the horizontal part of the upper side of the connecting plate 9, and then is pressed against the outside of the upper side of the connecting plate 9 by the fasteners passing through the two, and at the same time, the horizontal part of the upper side of the connecting plate 9 is also pressed against the left outer wall of the first-layer installation frame 1. The left end of the resistor wire group connecting piece 13 of the second-layer installation frame 1 overlaps the outside of the horizontal part of the lower side of the connecting plate 9, and then is pressed against the outside of the lower side of the connecting plate 9 by the fasteners passing through the two, and at the same time, the horizontal part of the lower side of the connecting plate 9 is also pressed against the left outer wall of the second-layer installation frame 1. In addition, the vertical part of the connecting plate 9 is respectively pressed against the outside of the first-layer installation frame 1 and the second-layer installation frame 2.

[0044] The upper and lower ends of the second connecting plate 10 are respectively pressed against the left outer wall of the third-layer mounting frame 1 and the left outer wall of the fourth-layer mounting frame 1 by fasteners. The left end of the third-layer mounting frame 1 resistor wire group connecting piece 13 and the left end of the fourth-layer mounting frame 1 resistor wire group connecting piece 13 are respectively pressed against the two ends of the second connecting plate 10 by fasteners one by one. That is: Figure 4As shown, after the left end of the resistor wire group connecting piece 13 of the third-layer installation frame 1 overlaps the outside of the horizontal portion of the upper side of the second connecting plate 10, it is pressed against the outside of the upper side of the second connecting plate 10 by the fasteners passing through the two, and at the same time, the horizontal portion of the upper side of the second connecting plate 10 is also pressed against the left outer wall of the third-layer installation frame 1. After the left end of the resistor wire group connecting piece 13 of the fourth-layer installation frame 1 overlaps the outside of the horizontal portion of the lower side of the second connecting plate 10, it is pressed against the outside of the lower side of the second connecting plate 10 by the fasteners passing through the two, and at the same time, the horizontal portion of the lower side of the second connecting plate 10 is also pressed against the left outer wall of the fourth-layer installation frame 1. In addition, the vertical portion of the second connecting plate 10 is respectively pressed against the outside of the third-layer installation frame 1 and the fourth-layer installation frame 1.

[0045] The upper and lower ends of the connecting plate 3 11 are respectively pressed against the right outer wall of the second-layer installation frame 1 and the right outer wall of the third-layer installation frame 1 by fasteners. The right end of the connecting piece 13 of the resistance wire group of the second-layer installation frame 1 and the right end of the connecting piece 13 of the resistance wire group of the third-layer installation frame 1 are respectively pressed against the two ends of the connecting plate 3 11 by fasteners one by one. That is: Figure 5 As shown, after the right end of the resistor wire group connecting piece 13 of the second-layer installation frame 1 overlaps with the inner side of the lateral part of the upper side of the connecting plate 3 11, it is pressed between the lateral part of the upper side of the connecting plate 3 11 and the outer side of the right end of the second-layer installation frame 1 by the fasteners passing through the two, and at the same time, the lateral part of the upper side of the connecting plate 3 11 is also pressed against the right end of the resistor wire group connecting piece 13 of the second-layer installation frame 1. After the right end of the resistor wire group connecting piece 13 of the third-layer installation frame 1 overlaps with the inner side of the lateral part of the lower side of the connecting plate 3 11, it is pressed between the lateral part of the lower side of the connecting plate 3 11 and the outer side of the right end of the third-layer installation frame 1 by the fasteners passing through the two, and at the same time, the lateral part of the lower side of the connecting plate 3 11 is also pressed against the right end of the resistor wire group connecting piece 13 of the third-layer installation frame 1. In addition, the vertical parts of the connecting plate 3 11 are respectively pressed against the outside of the second-layer installation frame 1 and the third-layer installation frame 1.

[0046] The upper and lower ends of the connecting plate 4 12 are respectively pressed against the right outer wall of the first layer installation frame 1 and the right outer wall of the fourth layer installation frame 1 by fasteners. The right end of the connecting piece 13 of the resistor wire group of the first layer installation frame 1 is pressed against the upper end of the connecting plate 4 12 by fasteners, and the lower end of the connecting plate 4 12 is bridged with one end of the power supply. The right end of the connecting piece 13 of the resistor wire group of the fourth layer installation frame 1 is pressed against the outer wall of the fourth layer installation frame 1 by fasteners and bridged with the other end of the power supply. Figure 5 As shown, the right end of the resistor wire group connecting piece 13 of the first-layer installation frame 1 overlaps the outside of the horizontal portion of the upper side of the connecting plate 4 11, and then is pressed against the horizontal portion of the upper side of the connecting plate 4 12 by the fastener passing through the two, and at the same time, the horizontal portion of the upper side of the connecting plate 4 11 is also pressed against the right end of the resistor wire group connecting piece 13 of the first-layer installation frame 1. In addition, the vertical portions of the connecting plate 4 12 are respectively pressed against the outside of the fourth-layer installation frame 1.

[0047] The fasteners used to fix the connecting plate 1 9, the connecting plate 2 10, the connecting plate 3 11 and the connecting plate 4 12 are M5 fasteners. The connecting plate 1 9, the connecting plate 2 10, the connecting plate 3 11 and the connecting plate 4 12 not only have the function of connecting the resistance wire group in series in the four-layer installation frame 1, but also have the function of stabilizing the four-layer installation frame 1 and improving the structural stability of the four-layer installation frame 1. The setting of the connecting plate improves the stability and reliability of the transition resistor. Example 2

[0048] The difference between this embodiment and embodiment 1 is that:

[0049] like Figure 4 and Figure 5 As shown, many saw teeth for clamping the resistance wire 2 are respectively provided on the lower surface of the upper ceramic sheet 4, the upper and lower surfaces of the middle ceramic sheet 4, and the lower surface of the lower ceramic sheet 4. The grooves of the saw teeth are clamped together with the resistance wire 2 to fix the resistance wire 2 and improve its stability. Example 3

[0050] The difference between this embodiment and embodiment 1 or embodiment 2 is that:

[0051] like Figure 4 and Figure 5 As shown, heat dissipation grooves 3 for heat dissipation are also provided at the upper and lower parts of each layer of the mounting frame 1, which are used for heat dissipation of the resistance wire sheet 2 during operation.

[0052] Other details of the present invention are all conventional techniques known to those skilled in the art.

[0053] It should be noted that the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0054] The protection scope of the present utility model is not limited to the technical solutions disclosed in the specific implementation methods. Any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A composite on-load tap changer transition resistor, comprising four layers of mounting frames arranged from top to bottom, three layers of ceramic sheets are installed from top to bottom in each layer of mounting frames, one layer of resistance wire sheet is respectively arranged between two adjacent layers of ceramic sheets of each layer of mounting frames, and two spring sheets are arranged outside each layer of mounting frames, the spring sheets are clamped outside the upper and lower layers of ceramic sheets and enable the ceramic sheets to clamp the resistance wire sheet; characterized in that: It also includes a connecting plate 1, a connecting plate 2, a connecting plate 3 and a connecting plate 4; wherein, The upper and lower ends of the connecting plate 1 are respectively pressed against the left outer wall of the first layer installation frame and the left outer wall of the second layer installation frame by fasteners; The upper and lower ends of the second connecting plate are respectively pressed on the left outer wall of the third-layer installation frame and the left outer wall of the fourth-layer installation frame by fasteners; The upper and lower ends of the connecting plate 3 are respectively pressed against the right outer wall of the second-layer installation frame and the right outer wall of the third-layer installation frame by fasteners; The upper and lower ends of the connecting plate 4 are respectively pressed against the right outer wall of the first-layer installation frame and the right outer wall of the fourth-layer installation frame by fasteners.

2. The transition resistor for the composite on-load tap changer according to claim 1 is characterized in that: The two layers of resistance wire sheets of each installation frame are connected in parallel to form a resistance wire group, and the resistance wire groups of the four layers of installation frames are connected in series in sequence.

3. The transition resistor for the composite on-load tap changer according to claim 2 is characterized in that: The connecting plate 1, the connecting plate 2, the connecting plate 3 and the connecting plate 4 are all conductive metal plates.

4. The transition resistor for the composite on-load tap changer according to claim 3 is characterized in that: The left end of the first-layer mounting frame resistance wire group and the left end of the second-layer mounting frame resistance wire group are respectively pressed one-to-one on the two ends of the connecting plate 1 by fasteners; The left end of the third-layer mounting frame resistance wire group and the left end of the fourth-layer mounting frame resistance wire group are respectively pressed one-to-one on the two ends of the connecting plate 2 by fasteners; The right end of the second-layer mounting frame resistance wire group and the right end of the third-layer mounting frame resistance wire group are respectively pressed one-to-one on the two ends of the connecting plate three by fasteners; The right end of the resistance wire group of the first-layer mounting frame is pressed against the upper end of the connecting plate four by the fastener, and the lower end of the connecting plate four is bridged with one end of the power supply. The right end of the resistance wire group of the fourth-layer mounting frame is pressed against the outer wall of the fourth-layer mounting frame by the fastener and bridged with the other end of the power supply.

5. The transition resistor for the composite on-load tap changer according to claim 4 is characterized in that: The connecting plate 1, the connecting plate 2, the connecting plate 3 and the connecting plate 4 are all U-shaped and arranged laterally, wherein the openings of the connecting plate 1 and the connecting plate 2 face left, and the openings of the connecting plate 3 and the connecting plate 4 face right.

6. The transition resistor for the composite on-load tap changer according to claim 5, characterized in that: The connecting plates 1, 2, 3, 4 and the connecting plates at both ends of the resistance wire are all pure copper plates, and the thickness of the connecting plates at both ends of the resistance wire is 3-6 mm.

7. The transition resistor for the composite on-load tap changer according to claim 1, characterized in that: The four-layer installation frames are stacked up and down to form a frame body, and the frame body is fixed to an insulating installation plate of the composite on-load tap changer by fasteners vertically passing through two diagonal corners thereof.

8. The transition resistor for the composite on-load tap changer according to claim 6, characterized in that: The fasteners used to fix the frame body are M8 fasteners, and the fasteners used to fix the connecting plate 1, the connecting plate 2, the connecting plate 3 and the connecting plate 4 are M5 fasteners.

9. The transition resistor for the composite on-load tap changer according to claim 1, characterized in that: A plurality of saw teeth for clamping the resistance wire are respectively arranged on the lower surface of the upper ceramic sheet, the upper and lower surfaces of the middle ceramic sheet, and the lower surface of the lower ceramic sheet.

10. The transition resistor for the composite on-load tap changer according to claim 1, characterized in that: Heat dissipation slots for heat dissipation are also provided at the upper and lower parts of each layer of the installation frame.

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