Iron core drawstring structure of converter transformer

Abstract

The utility model belongs to the field of transformers, and relates to a converter transformer iron core drawstring structure which comprises a steel drawstring, the two ends of the steel drawstring are connected with the center position of a first drawstring fixing plate and the center position of a second drawstring fixing plate, and a connecting screw is sleeved with an insulating pipe. Annular insulation pads are additionally arranged between the screw head of the connecting screw and the first drawstring fixing plate and the second drawstring fixing plate, fixing holes are formed in the two ends of the drawstring fixing plates in the length direction, inclined threaded holes are formed in the positions, corresponding to the fixing holes, of the clamp web, and the ends, close to the silicon steel sheets, of the inclined threaded holes are higher than the ends, away from the silicon steel sheets, of the inclined threaded holes. An insulating plate of a rectangular plate-shaped structure is arranged between the drawstring fixing plate and the clamping piece web plate, through holes corresponding to the fixing holes are formed in the two ends of the insulating plate, connecting screws penetrate through the fixing holes and the through holes to be screwed into the inclined threaded holes, and the two ends of an equipotential structure are connected with an equipotential base on the second drawstring fixing plate and the clamping piece web plate. According to the utility model, dual optimization of mechanical stability and electrical performance of the iron core drawstring of the converter transformer is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of transformer manufacturing, and in particular relates to a high-reliability converter transformer iron core drawstring structure, which is used for tightening and fixing iron core laminations. Background Art

[0002] As the only way to achieve optimal allocation of medium and long-distance energy, HVDC transmission technology has the advantages of low line loss and large power transmission capacity. The converter station is the core hub of the HVDC transmission system. The composition of the converter station mainly covers key equipment such as converter valves, converter transformers, reactors and filters. Among these components, the converter transformer undoubtedly occupies a pivotal position. The internal structure of the converter transformer is delicate and complex, mainly including key components such as iron core, coil, body and lead wire. As the core equipment of the HVDC transmission system, the complexity and importance of the internal structure of the converter transformer are self-evident. Through careful design and manufacturing, ensuring the efficient and stable operation of the converter transformer plays a vital role in ensuring the reliability and safety of the entire transmission system.

[0003] As the core skeleton of the converter transformer, the iron core not only bears the important responsibility of supporting and fixing all the internal components of the transformer, but also plays a key role in the magnetic circuit transmission of the transformer. In order to ensure the efficiency and stability of the iron core, the iron core of the converter transformer usually uses electrical steel sheets with extremely high magnetic permeability, which are precisely processed and stacked step by step to form a solid frame structure. In this frame structure, the core column and the side column are fixed with binding materials such as binding tape and weft-free tape to ensure the stability of the structure. The tie strap, as a key fastening component of the upper and lower yokes of the transformer core, is crucial to ensuring the mechanical and electrical strength reliability of the core. The design and manufacture of the core tie strap must strictly follow the relevant standards to ensure that the tie strap can maintain stable performance under extreme working conditions.

[0004] In the existing converter transformer structure, the core tie strap is often fixed with a single conventional screw. However, this conventional screw has the problem of uneven distribution of tightening force, which leads to uneven force between the core laminations, easily causing circulating current and overheating, posing a potential threat to the stable operation of the converter transformer. In addition, although a single screw can electrically achieve equipotential connection between the tie strap and the clamp, due to the limited current dispersion capacity of a single screw, this limits the equipotential effectiveness of the tie strap and the clamp to a certain extent. Therefore, in order to improve the performance and stability of the converter transformer, it is necessary to explore a more advanced core tie strap structure. Summary of the invention

[0005] The goal of this utility model is to design a high-reliability converter transformer core tie structure, aiming to significantly improve the fastening effect of the core laminations, ensure the integrity of the core lamination structure, and guarantee the magnetic circuit performance of the converter transformer, effectively solving the deficiencies and challenges in the prior art. The technical solutions adopted by this utility model are:

[0006] The iron core tie-strap structure of the converter transformer comprises a steel tie-strap with heat-resistant crepe paper wound on one side, the two ends of the steel tie-strap are respectively connected to the center positions of a first tie-strap fixing plate and a second tie-strap fixing plate, the first tie-strap fixing plate is a rectangular plate, the second tie-strap fixing plate is a rectangular plate with a convex structure and equal seats integrally formed on the upper surface, fixing holes are respectively provided at the two ends in the length direction of the first tie-strap fixing plate and the second tie-strap fixing plate, oblique threaded holes are respectively provided at positions corresponding to the fixing holes on the web of the clamp, the end of the oblique threaded hole close to the silicon steel sheet is higher than the end away from the silicon steel sheet, and the first Rectangular plate-shaped insulating plates are arranged between the drawstring fixing plate and the clamp web and between the second drawstring fixing plate and the clamp web. Through holes corresponding to the fixing holes are opened at both ends of the insulating plates. Insulating tubes are installed in the fixing holes of the first drawstring fixing plate and the second drawstring fixing plate. The height of the insulating tube is the same as the thickness of the first drawstring fixing plate and the second drawstring fixing plate. A circular ring-shaped insulating pad is installed on the screw head of the connecting screw. The connecting screw passes through the insulating tube in the fixing hole and the through hole of the insulating plate and is screwed into the oblique threaded hole. The two ends of the equal-position structure are respectively connected to the equal-position seat on the second drawstring fixing plate and the upper end of the clamp web.

[0007] Preferably, the equipotential structure includes copper stranded wire, terminal blocks and equipotential screws. The outer side of the copper stranded wire is wrapped with heat-resistant corrugated paper on one side. The two ends of the copper stranded wire are crimped and connected to one end of the terminal block. The other ends of the two terminal blocks are electrically connected to the upper end of the equipotential screws. The screw heads of the two equipotential screws are both covered with disc springs and flat washers. Internal threaded holes are provided on the front side surface of the equipotential seat and the upper side surface of the clamp web. The lower ends of the two equipotential screws are respectively screwed into the internal threaded holes of the equipotential seat and the clamp web, and a shielding cap is buckled on the top of the equipotential screws.

[0008] Preferably, the equipotential screw, disc spring and flat washer are all made of black material, and the shielding cap is made of stainless steel.

[0009] Preferably, the two ends of the steel drawstring are welded to the center of the first drawstring fixing plate and the second drawstring fixing plate respectively, and the end of the steel drawstring is welded with a welding groove, and the height of the solder around the welding groove does not exceed 2 mm.

[0010] Preferably, a metal washer and a disc spring are installed at the screw end of the connecting screw.

[0011] Preferably, the minimum depth of the connecting screw screwed into the oblique threaded hole of the clamp web is 25 mm, and the tightening torque of the core pull strap structure is 140 N.m.

[0012] Preferably, the steel pull strap is made of 6 mm thick S690Q steel plate, has a width of 60 mm, and a bending angle of 165°.

[0013] Preferably, a cross-shaped oil guide groove is provided on the surface of the annular insulating gasket.

[0014] Preferably, the first drawstring fixing plate and the second drawstring fixing plate are made of S690Q steel plate, the insulating tube is made of EPGC22 epoxy glass cloth laminated tube, the insulating plate is made of EPGC308 epoxy glass cloth laminated plate, and the annular insulating pad is made of EPGC203 epoxy glass cloth laminated plate.

[0015] Beneficial effects of the utility model:

[0016] The utility model can show significant advantages in the compression of the core laminations, ensure the integrity and stability of the core laminations, and provide effective guarantee for the safe and stable operation of the converter transformer. This solution is not only simple in structure, but also shows extremely high reliability in mechanical strength, and the implementation process is simple and easy. Through this solution, the dual optimization of the mechanical stability and electrical performance of the converter transformer core pull belt is achieved, laying a solid foundation for the long-term, stable and efficient operation of the converter transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the description of the specific implementation or the prior art. Obviously, the drawings described below are some specific implementations of the utility model. For ordinary technicians in this field, other drawings within the protection scope of this application can be obtained based on these drawings without creative work;

[0018] Figure 1 This is a schematic diagram of the overall structure of the iron core pull strap of an embodiment of the utility model;

[0019] Figure 2 2a is a schematic diagram of the fastening structure of the end of the iron core pull strap of the embodiment of the utility model, 2a is a schematic diagram of the fastening structure of the left end, and 2b is a schematic diagram of the fastening structure of the right end;

[0020] Figure 3 3a is a schematic diagram of the structure of the steel drawstring connected to the drawstring fixing plate of the embodiment of the utility model, 3a is a front view, and 3b is a top view;

[0021] Figure 4 It is a front view of the first drawstring fixing plate of the embodiment of the utility model;

[0022] Figure 5It is a front view of the second drawstring fixing plate of the embodiment of the utility model;

[0023] Figure 6 6a is a schematic structural diagram of a circular ring-shaped insulating pad according to an embodiment of the utility model, 6a is a front view, and 6b is an AA view of 6a;

[0024] In the figure, 1 is the clamp belly plate, 2 is the clamp insulation, 3 is the silicon steel sheet, 4 is the insulation plate, 5 is the insulation tube, 6 is the ring-shaped insulation pad, 7 is the first drawstring fixing plate, 8 is the steel drawstring, 9 is the second drawstring fixing plate, 10 is the connecting screw, 11 is the terminal, 12 is the copper stranded wire, 13 is the shielding cap, and 14 is the equal position screw. DETAILED DESCRIPTION

[0025] The technical solution of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present utility model, rather than all of the embodiments.

[0026] like Figure 1-6 As shown, a plurality of silicon steel sheets 3 are stacked step by step to form the main body of the converter transformer core, a clamp insulation 2 is arranged on the outer side of the silicon steel sheets 3 at both ends, a clamp web 1 is arranged on the outer side of the clamp insulation 2, and the clamp web 1 at both ends is tightened and fixed by the converter transformer core tie structure.

[0027] The converter transformer core tie structure includes a steel tie 8, wherein the steel tie 8 is made of a 6 mm thick S690Q high-strength low-alloy steel plate, has a width of 60 mm, and a bending angle α of 165°. Before use, the steel tie 8 needs to be wrapped with a single-sided heat-resistant corrugated paper, the thickness of which is 2 mm, to ensure insulation between the steel tie 8 and the silicon steel sheet 3.

[0028] The two ends of the steel strap 8 are welded to the center of the first strap fixing plate 7 and the second strap fixing plate 9, respectively. The first strap fixing plate 7 is located at the left end. The height of the weld between the first strap fixing plate 7 and the second strap fixing plate 9 and the end face of the steel strap 8 does not exceed 2 mm. This is a T-shaped butt weld. In order to ensure full penetration of the cross section, the steel strap 8 is welded with a groove, and the height of the weld around the groove is required to be no more than 2 mm. The first strap fixing plate 7 is a rectangular plate structure. The two ends of the first strap fixing plate 7 in the length direction are respectively provided with fixing holes. An oblique threaded hole is provided on the clamp web 1 at a position corresponding to the fixing hole of the first strap fixing plate 7. The end of the oblique threaded hole close to the silicon steel sheet 3 is higher than the end away from the silicon steel sheet 3. The connecting screw 10 passes through the fixing hole of the first strap fixing plate 7 and is screwed into the oblique threaded hole of the clamp web 1. The connecting screw 10 can be selected as a connecting screw of M16 specification. An insulating plate 4 is installed between the clamp web 1 and the first drawstring fixing plate 7. The insulating plate 4 is a rectangular plate-shaped structure. The length and width of the insulating plate 4 are slightly larger than the length and width of the first drawstring fixing plate 7 to ensure reliable insulation between the clamp web 1 and the first drawstring fixing plate 7. A through hole corresponding to the fixing hole of the first drawstring fixing plate 7 is opened on the insulating plate 4. The connecting screw 10 passes through the through hole of the insulating plate 4 to install the insulating plate 4 between the clamp web 1 and the first drawstring fixing plate 7. An insulating tube 5 is set on the connecting screw 10. The height of the insulating tube 5 is the same as the thickness of the first drawstring fixing plate 7. The insulating tube 5 is located between the outer periphery of the screw rod of the connecting screw 10 and the inner periphery of the fixing hole of the first drawstring fixing plate 7. A circular ring-shaped insulating pad 6 is installed between the screw head of the connecting screw 10 and the first drawstring fixing plate 7. The insulating tube 5 and the circular ring-shaped insulating pad 6 can ensure reliable insulation between the connecting screw 10 and the first drawstring fixing plate 7.

[0029] The minimum depth of the connecting screw 10 screwed into the oblique threaded hole of the clamp web 1 is 25mm, and the tightening torque of the drawstring structure is 140N.m. A metal washer and a disc spring are installed between the end of the connecting screw 10 and the annular insulating pad 6 to better tighten the connecting screw 10 (all tightening screws are equipped with flat washers and disc springs for locking). In the process, a hemp rope is passed through the through hole of the insulating plate 4, tied to the first drawstring fixing plate 7 and then knotted. The knotting point of the hemp rope is glued tightly with PVB glue.

[0030] A cross-shaped oil guide groove is provided on the annular insulating pad 6, which can effectively promote the smooth circulation of transformer oil and prevent gas trapping.

[0031] The welding structure of the second drawstring fixing plate 9 and the steel drawstring 8 at the right end, as well as the connection structure of the second drawstring fixing plate 9 and the clamp web 1, are basically the same as the first drawstring fixing plate 7, except that the structure of the second drawstring fixing plate 9 itself is different from that of the first drawstring fixing plate 7. The main structure of the second drawstring fixing plate 9 is the same as that of the first drawstring fixing plate 7, both of which are rectangular plate structures. The upper surface of the main structure of the second drawstring fixing plate 9 is integrally formed with a convex structure equal position seat, and the two ends of the copper stranded wire 12 are respectively crimped to one end of the connecting terminal 11 using a special crimping tool. The outer side of the copper stranded wire 12 is wrapped with heat-resistant corrugated paper with a thickness of 2mm on one side. The front side of the equal position seat and the upper side of the clamp web 1 are both provided with internal threaded holes, and the other ends of the two connecting terminals 11 are electrically connected. The upper end of the equipotential screw 14 and the lower end of the equipotential screw 14 are screwed into the internal threaded holes of the equipotential seat and the clamp web 1. The equipotential screw 14 adopts an M8 equipotential screw. The shielding cap 13 is buckled on the top of the equipotential screw 14. The shielding cap 13 is a one-piece cap structure, including a washer iron sheet and a cap welded together. The edge of the cap is rotatably connected relative to the edge of the washer iron sheet. When tightening, the washer iron sheet is screwed between the screw head and the washer of the equipotential screw 14. After tightening, the cap is rotated and buckled on the screw head of the equipotential screw 14. The terminal 11, the copper stranded wire 12 and the equipotential screw 14 constitute the equipotential structure of the core drawstring. A disc spring and a flat washer can also be installed on the upper end of the equipotential screw 14. The disc spring and the flat washer can make the fastening of the equipotential screw 14 more secure. The shielding cap plays a role in uniform electric field. The copper stranded wire 12 connects the second drawstring fixing plate 9 and the clamp web 1 to form a reliable equipotential. The clamp web 1 has a separate grounding seat connected to a separate grounding wire. The grounding wire is crimped to the copper head and then led to the outside of the transformer for separate grounding. The equipotential screw 14, disc spring, and flat washer are all made of black material, and the shielding cap 13 is made of stainless steel. The tightening torque of the equipotential point is 50N.m.

[0032] The first drawstring fixing plate 7 and the second drawstring fixing plate 9 are made of S690Q low alloy steel plate. The insulating tube 5 uses epoxy glass cloth laminate tube EPGC22, the insulating plate 4 uses epoxy glass cloth laminate board EPGC308, and the annular insulating pad 6 uses epoxy glass cloth laminate board EPGC203.

[0033] Before the converter transformer core is clamped and fixed, the core yoke is temporarily tied and fastened with a polyester binding tape, and then the converter transformer core tie-strap structure of the utility model embodiment is used. The two ends of a single steel tie-strap 8 are respectively connected to the first tie-strap fixing plate 7 and the second tie-strap fixing plate 9. The first tie-strap fixing plate 7 and the second tie-strap fixing plate 9 are both accurately fastened and tightened by two connecting screws 10 to ensure that the four key points form a stable and reliable clamping structure. The converter transformer core tie-strap structure of the utility model embodiment is adopted. The tie-strap structure tightens the clamp web 1 to clamp the clamp insulation 2 and the silicon steel sheet 3 along the lamination direction to prevent the converter transformer core lamination from loosening and ensure the integrity of the core lamination. At the same time, the equipotential line is arranged to ensure the single-point reliable grounding of the tie-strap structure.

[0034] In the embodiments of the utility model, the technical features not described in detail are all existing technologies or conventional technical means and will not be described in detail here.

[0035] Finally, it should be noted that the above embodiments are only specific implementation methods of the present utility model, which are used to illustrate the technical solution of the present utility model, rather than to limit it, and the protection scope of the present utility model is not limited thereto. Those skilled in the art should understand that any technician familiar with the technical field can modify the technical solution recorded in the above embodiments within the technical scope disclosed by the present utility model, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiment of the present utility model, and should be covered within the protection scope of the present utility model.

Claims

1. A converter transformer core tie-belt structure, comprising a steel tie-belt wound with heat-resistant crepe paper on one side, characterized in that: The two ends of the steel drawstring are respectively connected to the center positions of the first drawstring fixing plate and the second drawstring fixing plate, the first drawstring fixing plate is a rectangular plate, the second drawstring fixing plate is a rectangular plate with an integrally formed upper surface provided with a convex structure equal position seat, the first drawstring fixing plate and the second drawstring fixing plate have fixing holes at both ends in the length direction, an oblique threaded hole is provided at a position corresponding to the fixing hole on the clamp web, the end of the oblique threaded hole close to the silicon steel sheet is higher than the end away from the silicon steel sheet, an insulating plate of a rectangular plate structure is provided between the first drawstring fixing plate and the clamp web, and between the second drawstring fixing plate and the clamp web, through holes corresponding to the fixing holes are provided at both ends of the insulating plate, insulating tubes are installed in the fixing holes of the first drawstring fixing plate and the second drawstring fixing plate, the height of the insulating tube is the same as the thickness of the first drawstring fixing plate and the second drawstring fixing plate, a circular ring-shaped insulating pad is installed on the screw head of the connecting screw, the connecting screw passes through the insulating tube in the fixing hole and the through hole of the insulating plate and is screwed into the oblique threaded hole, and the two ends of the equal position structure are respectively connected to the equal position seat on the second drawstring fixing plate and the upper end of the clamp web.

2. The converter transformer core tie-belt structure according to claim 1, characterized in that: The equipotential structure includes copper stranded wire, terminal blocks and equipotential screws. The outer side of the copper stranded wire is wrapped with heat-resistant crepe paper on one side. The two ends of the copper stranded wire are crimped and connected to one end of the terminal block respectively. The other ends of the two terminal blocks are electrically connected to the upper end of the equipotential screws respectively. The screw heads of the two equipotential screws are both covered with disc springs and flat washers. The front side surface of the equipotential seat and the upper side surface of the clamp web are both provided with internal threaded holes. The lower ends of the two equipotential screws are respectively screwed into the internal threaded holes of the equipotential seat and the clamp web, and a shielding cap is buckled on the top of the equipotential screws.

3. The converter transformer core tie-belt structure according to claim 2, characterized in that: The equipotential screw, disc spring and flat washer are all made of black material, and the shielding cap is made of stainless steel.

4. The converter transformer core tie-belt structure according to claim 2, characterized in that: The two ends of the steel drawstring are welded to the center of the first drawstring fixing plate and the second drawstring fixing plate respectively, and the end of the steel drawstring is welded with a welding groove, and the height of the solder around the welding groove does not exceed 2mm.

5. The converter transformer core tie-belt structure according to claim 2, characterized in that: A metal washer and a disc spring are installed at the screw end of the connecting screw.

6. The converter transformer core tie-belt structure according to claim 5, characterized in that: The minimum depth of the connecting screw being screwed into the oblique threaded hole of the clamp web is 25 mm, and the tightening torque of the core pull strap structure is 140 N.m.

7. The converter transformer core tie-belt structure according to claim 2, characterized in that: The steel pull belt is made of 6mm thick S690Q steel plate, with a width of 60mm and a bending angle of 165°.

8. The converter transformer core tie-belt structure according to claim 2, characterized in that: A cross-shaped oil guide groove is provided on the surface of the annular insulating pad.

9. The converter transformer core tie-belt structure according to claim 2, characterized in that: The first drawstring fixing plate and the second drawstring fixing plate are made of S690Q steel plate, the insulating tube is made of EPGC22 epoxy glass cloth laminated tube, the insulating plate is made of EPGC308 epoxy glass cloth laminated plate, and the annular insulating pad is made of EPGC203 epoxy glass cloth laminated plate.

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