1250A oil immersed combined on-load tap-changer contact system

Abstract

The utility model discloses a 1250A oil immersed combined on-load tap-changer contact system, which comprises an oil chamber insulating cylinder, an arc-shaped plate, a rotating shaft, a main contact, a main static contact, an inner side contact assembly, a button contact assembly, a contact support assembly and a soft connection assembly, the two shifting forks are respectively connected with two rotatable active contacts, and the end parts of the active contacts are in contact connection with the main static contacts; a contact seat is arranged in the oil chamber insulating cylinder, a button contact assembly is arranged in the contact seat, and the inner side contact assembly is in contact connection with the button contact assembly, so that a current-carrying loop is formed. By adopting the contact system provided by the utility model, single-phase or three-phase 1250A current-carrying connection and separation are realized in the switching process of the on-load tap-changer, so that the switching of the selector is completed, the whole structure is simple, the system is simplified, the cost is saved, the failure rate is reduced, and the contact system is suitable for popularization and application.

Description

Technical Field

[0001] The utility model relates to the technical field of on-load tap-changers for transformers, and particularly relates to a contact system of a 1250A oil-immersed combined on-load tap-changer. Background Art

[0002] In the power system, since power generation and power consumption cannot be kept balanced, voltage fluctuations are inevitable, and thus on-load tap-changers are required to adjust the voltage. The on-load tap-changer is used in power transformers or industrial transformers to tap under the condition of no interruption of the load current (i.e., on-load condition), change the turns ratio of the transformer, and thus adjust the output voltage of the transformer. Among them, the combined on-load tap-changer is composed of a switching switch with current conversion and a tap selector for pre-selecting the tap position without current. The switching switch includes a switching core and a switching switch oil chamber. The switching core mainly consists of a switching switch insulating cylinder, upper and lower flanges, three arc-shaped plates forming a cylindrical shape, a spring energy storage quick mechanism, a transmission central shaft, a contact system fixed on each arc-shaped plate, a transition resistor, and a contact switching mechanism.

[0003] At present, the power supply is becoming increasingly tense in various countries around the world, and there are more and more large-capacity transformers. Correspondingly, the required current of the supporting on-load tap-changer is getting higher and higher. The maximum current of the existing composite three-phase delta-connected on-load tap-changer can only reach 500A. The combined on-load tap-changer in three-phase integration can only achieve the star connection method, and three single-phase switches are required to achieve the delta connection method, resulting in a significant increase in manufacturing costs and operating costs. Content of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a contact system of a large-current oil-immersed combined on-load tap-changer to meet the use requirements of large-capacity transformers in view of the problems in the background art. By using this contact system, single-phase 1250A current-carrying can be achieved. By combining three contact systems, three-phase delta-connected 1250A current-carrying can also be obtained, thus ensuring the normal operation of the power system. Specifically, it is a contact system of a 1250A oil-immersed combined on-load tap-changer.

[0005] To solve the above technical problems, the technical solution adopted by the present utility model is as follows: A 1250A oil-immersed combined on-load tap-changer contact system, comprising an oil chamber insulating cylinder, and an arc plate and a rotating shaft installed inside the oil chamber insulating cylinder. There are two arc plates, and the two arc plates are arranged in a ring shape outside the rotating shaft. The contact system further includes a moving contact, a static main contact, an inner contact assembly, a button contact assembly, a contact support assembly, and a flexible connection assembly. Two fork levers, namely an upper fork lever and a lower fork lever, are installed on the rotating shaft along its axial direction. Two rotatable moving contacts are respectively connected to the edges of the upper fork lever and the lower fork lever. The static main contact is installed in the arc plate through the contact support assembly. The inner contact assembly and the flexible connection assembly are respectively connected to the static main contact installed in the arc plate. The end of the moving contact is in contact connection with the static main contact;

[0006] Two sets of contact seats are provided in the oil chamber insulating cylinder. The two sets of contact seats are arranged in parallel on the upper side and the lower side of the oil chamber insulating cylinder and correspond to the inner contact assembly. Two vertically arranged button contact assemblies are provided in each contact seat located inside the oil chamber insulating cylinder, and the upper and lower two sets of contact seats located outside the oil chamber insulating cylinder are respectively short-circuited with each other through wires to form a parallel circuit;

[0007] During the switching process of the on-load tap-changer, the rotating shaft drives the moving contact to rotate synchronously with the rotating shaft by the fork lever. When the moving contact switches to contact with the static main contact, the inner contact assembly is pushed to move outwards through the contact support assembly, and a space for avoiding movement is formed through the flexible connection assembly, so that the inner contact assembly is in contact connection with the button contact assembly, thereby constituting a current-carrying circuit.

[0008] Furthermore, a 1250A oil-immersed combined on-load tap-changer contact system according to the present utility model is adopted. The moving contact is arranged in a horn structure having two horn contacts and a rotating connecting part. The end of the horn contact adopts a double-contact structure. An installation plate is further provided in the oil chamber insulating cylinder. The installation plate includes an upper installation plate and a lower installation plate. The upper installation plate and the lower installation plate are installed in parallel in the oil chamber insulating cylinder. The rotating shaft is rotatably connected to the installation plate. A screw rod arranged parallel to the rotating shaft is further provided in the installation plate. The moving contact is sleeved on the screw rod through the rotation center of the rotating connecting part. A connecting key corresponding to the fork is provided on the rotating shaft. The fork is fixed to the rotating shaft through the connecting key. The moving contact is connected to the fork through the end of the rotating connecting part. The two moving contacts connected to the fork are arranged at an interval of 120° along the circumferential direction of the oil chamber insulating cylinder outside the rotating shaft. During the switching process of the on-load tap-changer, under the action of the upper fork and the lower fork, through the mutual cooperation of the moving contact, the main static contact, the inner contact assembly, the button contact assembly, the contact support assembly and the flexible connection assembly, the inner contact assembly is brought into contact and connected with the button contact assembly, and is short-circuited with each other outside the oil chamber insulating cylinder to form a parallel circuit, constituting a 1250A current-carrying circuit.

[0009] Furthermore, a 1250A oil-immersed combined on-load tap-changer contact system according to the present utility model is adopted. The inner contact assembly includes a static contact, a neutral point contact and a flexible conductive component. The neutral point contact is arranged in the middle of the arc-shaped plate. There are two static contacts, namely an odd-number static contact and an even-number static contact. The odd-number static contact and the even-number static contact are symmetrically arranged in the arc-shaped plates on both sides of the neutral point contact. Both the odd-number static contact and the even-number static contact are composed of two parallel contacts, and a copper-tungsten alloy contact is welded to the contact end of one of the contacts. The static contact is connected to the contact support assembly. The flexible conductive component is arranged at the tail of the rotating connecting part of the moving contact. The neutral point contact is connected to the moving contact through the flexible conductive component.

[0010] Furthermore, a 1250A oil-immersed combined on-load tap-changer contact system according to the present utility model is adopted. The flexible conductive component includes a flexible conductive connecting piece and a conductive rod. The conductive rod is fixed in the arc-shaped plate. One end of the flexible conductive connecting piece is riveted to the tail of the rotating connecting part of the moving contact, and the other end is fixed to the conductive rod. The neutral point contact is fixed to the end of the conductive rod. The neutral point contact and the static contact are respectively in contact connection with the button contact assembly installed in the contact seat.

[0011] Furthermore, a 1250A oil-immersed combined on-load tap changer contact system described in the utility model is adopted, and the two arc-shaped plates installed in the insulating cylinder of the oil chamber are respectively fixed to the upper mounting plate and the lower mounting plate by first connecting bolts, and a through hole corresponding to the rotating shaft is provided in the mounting plate, and a bearing and a retaining ring are provided in the through hole, and the rotating shaft is rotatably connected to the mounting plate through the bearing; the active contact, the conductive rod and the neutral point contact are respectively fixedly connected to the upper mounting plate and the lower mounting plate by second connecting bolts to form an integrated structure.

[0012] Furthermore, a 1250A oil-immersed combined on-load tap changer contact system described in the utility model is adopted, and the contact support assembly includes a guide sleeve, a contact return spring, a second pressure plate and a connecting pin. The guide sleeve is installed in the arc plate, and the main static contact is installed in the guide sleeve. One end of the main static contact is in contact and connected with the active contact, and the other end is fixed in the arc plate through a soft connection assembly; the second pressure plate is arranged on the outside of the guide sleeve, and a connecting pin is provided in the second pressure plate, one end of the contact return spring is placed in the main static contact, and the other end is sleeved on the connecting pin in the second pressure plate; the contact support assembly is in contact and connected with the static contact through the second pressure plate.

[0013] Furthermore, a 1250A oil-immersed combined on-load tap changer contact system according to the utility model is adopted, wherein the soft connection assembly includes a soft conductive copper sheet, a connecting rivet, a first pressure plate, a gasket, a third connecting bolt and a fourth connecting bolt. One end of the soft conductive copper sheet passes through the first pressure plate and the soft conductive copper sheet in sequence through the connecting rivet and is riveted together with the main static contact. The middle part of the soft conductive copper sheet is fixed to the arc plate by the third connecting bolt, and a gasket corresponding to the third connecting bolt is provided on the soft conductive copper sheet. The other end of the soft conductive copper sheet and the two ends of the static contact are fixed to the arc plate by a fourth connecting bolt; when the rotating shaft is switched with the on-load tap changer, the shift fork drives the active contact to rotate synchronously with the rotating shaft, and the static contact in the inner contact assembly is pushed outward by the contact return spring in the contact support assembly, and an avoidance space is formed by the soft conductive copper sheet in the soft connecting assembly to avoid jamming, so that the static contact and neutral point contact in the inner contact assembly are respectively in contact and connected with the button contact assembly, thereby forming a current-carrying circuit.

[0014] Furthermore, a 1250A oil-immersed combined on-load tap-changer contact system of the present utility model is adopted. The button contact assembly includes a button contact, a flexible conductive sheet, a support, a button return spring, and a fifth connecting bolt. The button contact is riveted to the support through the flexible conductive sheet. The button return spring is arranged inside the support. The support is snap-fitted inside the contact seat. The flexible conductive sheet is fixed to the contact seat through the fifth connecting bolt. An installation hole corresponding to the contact seat is provided in the oil chamber insulating cylinder. The contact seat is arranged in the oil chamber insulating cylinder through the installation hole. The button contact assembly is in contact connection with the neutral point contact and the static contact through the corresponding button contact, and reliable contact is achieved under the action of the button return spring.

[0015] Furthermore, a 1250A oil-immersed combined on-load tap-changer contact system of the present utility model is adopted. The button contact assembly further includes a sealing ring. The sealing ring is arranged in the installation hole. The contact seat is hermetically connected to the oil chamber insulating cylinder through the sealing ring.

[0016] Furthermore, a 1250A oil-immersed combined on-load tap-changer contact system of the present utility model is adopted. The button contact assembly is fixedly connected to the contact seat along the vertical direction of the oil chamber insulating cylinder. The button contact assemblies installed in the contact seat are respectively an odd-number contact assembly, an even-number contact assembly, and a neutral point contact assembly. Among them, the odd-number contact assembly, the even-number contact assembly, and the neutral point contact assembly are respectively in contact connection with the odd-number static contact and the even-number static contact in the static contact, and the neutral point contact. The odd-number contact assemblies in the upper and lower two groups of contact seats located outside the oil chamber insulating cylinder are short-circuited, the even-number contact assemblies are short-circuited, and the neutral point contact assemblies are short-circuited to form a parallel circuit. During the switching process of the on-load tap-changer, the rotating shaft is in contact connection with the button contact assembly through the inner contact assembly to form a single-phase or three-phase 1250A current-carrying circuit.

[0017] Adopting the 1250A oil-immersed combined on-load tap-changer contact system of the present utility model, compared with the prior art, its beneficial effects are as follows: Since two rotatable active contacts are respectively connected in the upper and lower fork levers fixed on the rotating shaft, and main static contacts and inner contact assemblies corresponding to the active contacts are provided on two arc-shaped plates, and a button contact assembly corresponding to the inner contact assembly is provided on the contact seat in the oil chamber insulating cylinder. The two groups of active contacts, inner contact assemblies and button contact assemblies are respectively arranged axially up and down along the rotating shaft in the oil chamber insulating cylinder, which can not only save the installation space of the transformer, but also save the volume and manufacturing cost of the transformer. At the same time, since the two active contacts connected to the fork lever are arranged at an interval of 120° along the circumferential direction of the oil chamber insulating cylinder outside the rotating shaft, during the switching process of the on-load tap-changer with the rotating shaft, first the active contacts contact with the main static contacts, and then through the connection and separation of the inner contact assembly and the button contact assembly, the purpose of single-phase or three-phase 1250A current conduction can be achieved, thus completing the conversion of the selector; in addition, since the power of the rotating shaft is taken from the energy storage mechanism connected to the switch at the upper end of the contact system, its action time and phase are affected by the energy storage mechanism of the on-load tap-changer, so that the potential switch and its supporting control and operating systems can be omitted.

[0018] Thus, adopting the contact system of the present utility model, since the contact seat in the oil chamber insulating cylinder adopts a double-axis lead-out method, two button contact assemblies installed inside the contact seat form a floating structure, and the inner contact assembly installed on the arc-shaped plate includes a static contact, a neutral point contact and a soft conductive assembly, and the static contact is in contact connection with the active contact through a contact support assembly. Under the action of the contact return spring and the button return spring, through spring compensation, the reliable contact between the inner contact assembly and the button contact assembly is ensured. During the switching process of the on-load tap-changer, single-phase or three-phase 1250A current connection and separation are realized, thus completing the conversion of the selector. Its overall structure is simple, which not only simplifies the system, but also saves costs and reduces the failure rate, and is suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present utility model will be further described in detail below with reference to the drawings.

[0020] Figure 1 is a schematic plan layout structure diagram of the contact system of the present utility model;

[0021] Figure 2 is a schematic vertical layout structure diagram of the contact system of the present utility model;

[0022] Figure 3 is a schematic unfolded structure diagram of the arc-shaped plate of the contact system of the present utility model;

[0023] Figure 4It is a schematic structural diagram of the button contact assembly of the contact system of the present utility model.

[0024] As shown in the figure: 1 - rotating shaft, 2 - fork, 3 - moving contact, 4 - fixed main contact, 5 - guide sleeve, 6 - flexible conductive copper sheet, 7 - connecting rivet, 8 - first pressing plate, 9 - contact return spring, 10 - second pressing plate, 11 - fixed contact, 12 - arc plate, 13 - screw, 14 - button contact, 15 - flexible conductive sheet, 16 - support member, 17 - contact seat, 18 - button return spring, 19 - sealing ring, 20 - fifth connecting bolt, 21 - oil chamber insulating cylinder, 22 - flexible conductive connecting piece, 23 - conductive rod, 24 - neutral point contact, 25 - second connecting bolt, 26 - mounting plate, 27 - copper tungsten alloy contact, 28 - gasket, 29 - third connecting bolt, 30 - fourth connecting bolt, 31 - first connecting bolt, 32 - bearing, 33 - retaining ring. Specific embodiments

[0025] The technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model. Embodiment 1

[0026] As Figure 1As shown, this embodiment provides a 1250A oil-immersed combined on-load tap changer contact system, which includes an oil chamber insulating cylinder 21, and an arc-shaped plate 12 and a rotating shaft 1 installed in the oil chamber insulating cylinder 21. Two groups of contact seats 17 are provided in the oil chamber insulating cylinder 21, and also include an active contact 3, a main static contact 4, an inner contact assembly, a button contact assembly, a contact support assembly and a soft connection assembly. Two shift forks 2 are installed on the rotating shaft 1 along its axial direction, namely an upper shift fork and a lower shift fork. Two rotatable active contacts 3 are respectively connected to the edges of the upper shift fork and the lower shift fork. The main static contact 4 is installed in the arc-shaped plate 12 through the contact support assembly. The inner contact assembly and the soft connection assembly are respectively connected to the main static contact 4 installed in the arc-shaped plate 12, and the end of the active contact 3 is connected to the main static contact 4. contact connection; and two groups of contact seats 17 are provided in the oil chamber insulating cylinder 21, and the two groups of contact seats 17 are arranged in parallel on the upper and lower sides of the oil chamber insulating cylinder 21, and correspond to the inner contact assembly, and two vertically arranged button contact assemblies are provided in each contact seat 17 located on the inner side of the oil chamber insulating cylinder 21, and the upper and lower groups of contact seats 17 located on the outer side of the oil chamber insulating cylinder 21 are short-circuited with each other through wires to form a parallel circuit; during the switching process of the on-load tap changer, the rotating shaft 1 is driven by the fork 2 to rotate synchronously with the rotating shaft 1, and when the active contact 3 is switched to contact with the main static contact 4, the inner contact assembly is pushed outward by the contact support assembly, and an avoidance space is formed by the soft connection assembly, so that the inner contact assembly is in contact and connected with the button contact assembly, thereby forming a current-carrying circuit.

[0027] Specifically, the contact system described in this embodiment is adopted, and the inner contact assembly includes a static contact 11, a neutral point contact 24, a soft conductive connector 22 and a conductive rod 23; the button contact assembly includes a button contact 14, a soft conductive sheet 15, a support 16, a button reset spring 18 and a fifth connecting bolt 20; the contact support assembly includes a guide sleeve 5, a contact reset spring 9, a second pressure plate 10 and a connecting pin; the soft connection assembly includes a soft conductive copper sheet 6, a connecting rivet 7, a first pressure plate 8, a gasket 28, a third connecting bolt 29 and a fourth connecting bolt 30. The active contact 3 is configured as a ram's horn structure having two ram's horn contacts and a rotating connection portion, and the end of the ram's horn contact adopts a double-contact structure. A mounting plate 26 is also provided in the oil chamber insulating cylinder 21. The mounting plate 26 includes an upper mounting plate and a lower mounting plate. The upper mounting plate and the lower mounting plate are installed in parallel in the oil chamber insulating cylinder 21, and the rotating shaft 1 is rotatably connected to the mounting plate 26; a screw 13 arranged parallel to the rotating shaft 1 is also provided in the mounting plate 26, and the active contact 3 is placed on the screw 13 through the rotating center sleeve of the rotating connection portion.

[0028] The rotating shaft 1 is used for the transmission of the power of the contact system. The upper end of the contact system is connected to the energy storage mechanism of the on-load tap-changer, and the lower end is connected to the fork 2 through a connecting key. The roller of the fork 2 is placed in the fork groove of the moving contact 3. The rotation center of the moving contact 3 is sleeved on the screw 13. When the rotating shaft 1 drives the fork 2 to rotate, the fork 2 drives the moving contact 3 to act around the screw 13. The main static contact 4 is installed in the guide sleeve 5. One end of the main static contact 4 is in contact with the moving contact 3, and the other end is riveted together with the flexible conductive copper sheet 6 through the connecting rivet 7 and the first pressing plate 8. One end of the contact return spring 9 is placed inside the main static contact 4, and the other end is sleeved on the connecting pin of the second pressing plate 10. When the moving contact 2 moves in place, its end will push the main static contact 4 out 2.5 mm along the axis of the guide sleeve, that is, the contact return spring 9 will be compressed by 2.5 mm, ensuring that there is a certain contact pressure between the moving contact 2 and the main static contact 4, so as to ensure reliable contact. The other side of the second pressing plate 10 is stuck on the static contact 11 for position limitation, and both ends of the static contact 11 are fixed on the arc plate 12. The button contact 14 is riveted together with the flexible conductive sheet 15 and the support member 16. The button contact 14 is respectively in contact with the static contact 11 and the neutral point contact 24 installed on the arc plate 12. At this time, the support member 16 presses the button return spring 18 and is stuck inside the contact seat 17. The flexible conductive sheet 15 is fixed on the contact seat 17 through the fifth connecting bolt 20. The contact seat 17 is installed in the installation hole of the oil chamber insulating cylinder 21, and a sealing ring 19 is arranged in the installation hole. In this way, it can be sealed through the sealing ring 19, and the outside is fastened with a nut. The tail end of the moving contact 3 is riveted with a flexible conductive connecting piece 22, and the other end of the flexible conductive connecting piece 22 is fixed on the conductive rod 23 through a bolt. The neutral point contact 24 is fixed on the conductive rod 23 through a bolt. In the circumferential direction, two groups of contacts are arranged at intervals of 120°. In the vertical direction, the two groups of contacts are arranged in a parallel state. In this way, outside the oil chamber insulating cylinder 21, the odd numbers and odd numbers, even numbers and even numbers, and neutral points and neutral points corresponding up and down in the contact seat 17 can be short-circuited through wires to form a parallel circuit.

[0029] The above takes the conversion of the moving contact 3 to the odd side as an example to illustrate the formation of the current-carrying path of the contact system for large current.

[0030] As Figure 2 shown, in the vertical direction, the moving contact 3 is designed with a double-contact structure at the end, and each contact can independently contact the main static contact 4. Taking the odd side as an example, there are 2 groups of moving contacts 3 with a total of four contacts in the vertical direction of each group of odd sides, and four groups of main static contacts 4 in the same plane. As Figure 3As shown, one end of each group of main static contacts 4 is riveted to one end of a flexible conductive copper sheet 6. The middle part of the flexible conductive copper sheet 6 is fastened to the arc-shaped plate 12 with a gasket 28 and a third bolt 29. The other end of the flexible conductive copper sheet 6 and both ends of the static contact 11 are fixed to the arc-shaped plate 12 through a fourth bolt 30. On the two arc-shaped plates 12, a group of odd-numbered contacts and a group of even-numbered contacts are arranged respectively, and among them, the odd-numbered contacts and the even-numbered contacts are distributed on both sides of the neutral point contact (24).

[0031] To make the structure of the entire contact system more compact, the rotating shaft 1 is positioned on the upper and lower arranged mounting plates 26 through bearings 32 and retaining rings 33. The moving contact 3, the conductive rod 23, and the neutral point contact 24 are fixed to the mounting plate 26 through a second connecting bolt 25, and the two symmetrically arranged arc-shaped plates 12 are fixed to the mounting plate 26 through a first bolt 31. Through the above connections, an integral body can be formed inside the contact system.

[0032] As Figure 4 shown, the button contact assembly includes a button contact 14, a flexible conductive sheet 15, a support member 16, a button return spring 18, a sealing ring 19, and a fifth connecting bolt 20. The button contact 14 is riveted to the support member 16 through the flexible conductive sheet 15. The button return spring 18 is arranged inside the support member 16. The support member 16 is snap-fitted inside the contact seat 17. The flexible conductive sheet 15 is fixed to the contact seat 17 through a fifth connecting bolt 20. In the oil chamber insulating cylinder 21, there is an installation hole corresponding to the contact seat 17. The sealing ring 19 is arranged inside the installation hole. The contact seat 17 is hermetically connected to the oil chamber insulating cylinder 21 through the sealing ring 19 arranged inside the installation hole. Since two groups of button contacts 14 are installed in a group of contact seats 17 on the oil chamber insulating cylinder 21, and the two groups of contact seats 17 are arranged side by side in the vertical direction, so that there are a total of four groups of button contacts 14 at each position in the vertical direction.

[0033] After the integral body inside the contact system is placed inside the oil chamber insulating cylinder 21, the static contact 11 and the neutral point contact 24 in the arc-shaped plate 12 are in contact with the button contact 14, so that the button return spring 18 is compressed by 3 mm, and through the button return spring 18, a certain contact pressure can be applied to the contact between the static contact 11, the neutral point contact 24 and the button contact 14, which can ensure reliable contact.

[0034] In the specific application process, since the button contact assembly is fixedly connected to the contact seat 17 along the vertical direction of the oil chamber insulating cylinder 21, and the button contact assemblies installed in the contact seat 17 are respectively an odd contact assembly, an even contact assembly and a neutral point contact assembly, wherein the odd contact assembly, the even contact assembly and the neutral point contact assembly are respectively in contact with the odd static contacts and the even static contacts in the static contact 11, and the neutral point contact 24, while the odd contact assemblies and the odd contact assemblies in the upper and lower groups of contact seats 17 outside the oil chamber insulating cylinder 21 are respectively in contact with each other. The components are short-circuited, the even-numbered contact components are short-circuited, and the neutral point contact components are short-circuited to form a parallel circuit; during the switching process of the on-load tap changer, the rotating shaft 1 is in contact with the button contact component through the inner contact component, that is, the odd-numbered static contacts in the static contacts 11 are in contact with the odd-numbered contact components, or the even-numbered static contacts in the static contacts 11 are in contact with the even-numbered contact components, and the neutral point contact 24 is in contact with the neutral point contact assembly, thereby forming a single-phase or three-phase 1250A current-carrying circuit. Example 2

[0035] This embodiment is based on Example 1. To improve the overall performance of the contact system, the main static contact 4 is stacked in four pieces, each contact piece contacting one contact piece of the active contact 3, thus ensuring reliable contact. At the same time, a copper-tungsten alloy contact 27 is welded to the contact end of one of the contacts. Through the welded copper-tungsten alloy contact 27, during the synchronous rotation of the static contact 11 with the arc plate 12, a contact return spring 9 provided in the main static contact 4 can provide spring compensation. The compensation amount can be approximately 1mm greater than that of other contacts. When the static contact 11 finally leaves the active contact 3, it can assume the task of extinguishing the arc after the active contact 3 leaves. At the same time, the copper-tungsten alloy is also resistant to electrical corrosion, which can improve the overall performance of the contact system.

[0036] The utility model provides a 1250A oil-immersed modular on-load tap changer contact system. This contact system utilizes a centrally located rotating shaft 1 to rotate two shift forks 2. The shift forks 2 then shift the tail of a driving contact 3, causing it to rotate around a screw 13. Once the driving contact 3 is in position, it contacts the main static contact 4, which is mounted on a curved plate 12 via a guide sleeve 5. The main static contact 4 incorporates a built-in contact return spring 9, ensuring a certain contact pressure when the driving contact 3 makes contact, ensuring reliable contact. When the contact system is placed within the switch oil chamber, the static contact 11 and neutral contact 24 on the outer side of the curved plate 12 make contact with the button contact 14. The button contact 14 is riveted to the support 16 through a soft conductive sheet 15, and a button return spring 18 is provided inside the support 16, so that the static contact 11 and the neutral point contact 24 on the outside of the arc plate 12 have a certain contact pressure when they contact the button contact 14, ensuring reliable contact.

[0037] It can be seen that with the contact system of the present utility model, since the contact seat 17 in the oil chamber insulating cylinder 21 adopts a biaxial lead-out method, the two button contact assemblies installed inside the contact seat 17 form a floating structure, and the inner contact assembly installed on the arc-shaped plate 12 includes a static contact 11, a neutral point contact 24 and a soft conductive assembly. The static contact 11 is in contact connection with the main contact 3 through a contact support assembly. Under the action of the contact return spring 9 and the button return spring 18, through spring compensation, the reliable contact between the inner contact assembly and the button contact assembly is ensured. During the switching process of the on-load tap-changer, the single-phase or three-phase 1250A current-carrying connection and separation are realized, thereby completing the conversion of the selector. Its overall structure is simple, which not only simplifies the system, but also saves costs and reduces the failure rate, and is suitable for popularization and application.

[0038] Other details not elaborated in the present utility model are all well-known conventional techniques in the art, so no detailed description is given.

[0039] The protection scope of the present utility model is not limited to the technical solutions disclosed in the specific embodiments. The above are only the preferred embodiments of the present utility model and do not limit the present utility model. Any minor modifications, equivalent replacements and improvements made according to the technical solutions of the present utility model shall be included in the protection scope of the technical solutions of the present utility model.

Claims

1. A 1250A oil-immersed combined on-load tap-changer contact system, comprising an oil chamber insulating cylinder (21), and an arc-shaped plate (12) and a rotating shaft (1) installed inside the oil chamber insulating cylinder (21). There are two arc-shaped plates (12), and the two arc-shaped plates (12) are arranged in a ring outside the rotating shaft (1). It is characterized in that: The contact system further comprises an active contact (3), a main static contact (4), an inner contact assembly, a button contact assembly, a contact support assembly and a soft connection assembly. Two shift forks (2) are mounted on the rotating shaft (1) along its axial direction, namely an upper shift fork and a lower shift fork. Two rotatable active contacts (3) are connected to the edges of the upper shift fork and the lower shift fork respectively. The main static contact (4) is mounted in the arc plate (12) through the contact support assembly. The inner contact assembly and the soft connection assembly are respectively connected to the main static contact (4) mounted in the arc plate (12). The end of the active contact (3) is in contact with the main static contact (4). Two groups of contact seats (17) are provided in the oil chamber insulating cylinder (21). The two groups of contact seats (17) are arranged in parallel on the upper side and the lower side of the oil chamber insulating cylinder (21) and correspond to the inner contact assembly. Two vertically arranged button contact assemblies are provided in each contact seat (17) located on the inner side of the oil chamber insulating cylinder (21), and the upper and lower groups of contact seats (17) located on the outer side of the oil chamber insulating cylinder (21) are short-circuited with each other through wires to form a parallel circuit. During the switching process of the on-load tap changer, the rotating shaft (1) is driven by the shift fork (2) to rotate synchronously with the rotating shaft (1); when the active contact (3) switches to contact with the main static contact (4), the inner contact assembly is pushed outward by the contact support assembly, and an avoidance space is formed by the soft connection assembly, so that the inner contact assembly is in contact with the button contact assembly to form a current-carrying circuit.

2. The contact system of a 1250A oil-immersed combined on-load tap-changer according to claim 1, characterized in that: The active contact (3) is configured as a ram's horn structure having two ram's horn contacts and a rotating connection portion, the ends of the ram's horn contacts adopt a double-contact structure, a mounting plate (26) is further provided in the oil chamber insulating cylinder (21), the mounting plate (26) comprises an upper mounting plate and a lower mounting plate, the upper mounting plate and the lower mounting plate are mounted in parallel in the oil chamber insulating cylinder (21), the rotating shaft (1) is rotatably connected to the mounting plate (26); a screw (13) arranged parallel to the rotating shaft (1) is further provided in the mounting plate (26), the active contact (3) is placed on the screw (13) through the rotating center sleeve of the rotating connection portion, a connecting key corresponding to the shift fork (2) is provided on the rotating shaft (1), the shift fork (2) The rotating shaft (1) is fixed to the rotating shaft (1) by a connecting key; the active contact (3) is connected to the shift fork (2) by the end of the rotating connection part, and the two active contacts (3) connected to the shift fork (2) are arranged on the outside of the rotating shaft (1) at intervals of 120 degrees along the circumferential direction of the oil chamber insulating cylinder (21); during the switching process of the on-load tap changer, the rotating shaft (1) cooperates with the active contact (3), the main static contact (4), the inner contact assembly, the button contact assembly, the contact support assembly and the soft connection assembly through the mutual cooperation of the active contact (3), the main static contact (4), the inner contact assembly, the button contact assembly, the contact support assembly and the soft connection assembly, and short-circuit each other through the outer side of the oil chamber insulating cylinder (21), forming a parallel circuit, forming a current carrying circuit of 1250A.

3. The contact system of a 1250A oil-immersed combined on-load tap-changer according to claim 2, characterized in that: The inner contact assembly includes a static contact (11), a neutral point contact (24) and a soft conductive assembly. The neutral point contact (24) is arranged in the middle of the arc-shaped plate (12). There are two static contacts (11), namely an odd-number static contact and an even-number static contact. The odd-number static contact and the even-number static contact are symmetrically arranged in the arc-shaped plates (12) on both sides of the neutral point contact (24). Both the odd-number static contact and the even-number static contact are composed of two parallel contacts, and a copper-tungsten alloy contact (27) is welded to the contact end of one of the contacts. The static contact (11) is connected to the contact support assembly. The soft conductive assembly is arranged at the tail of the rotary connection part of the active contact (3). The neutral point contact (24) is connected to the active contact (3) through the soft conductive assembly.

4. The contact system of a 1250A oil-immersed combined on-load tap-changer according to claim 3, characterized in that: The soft conductive assembly includes a soft conductive connector (22) and a conductive rod (23). The conductive rod (23) is fixed in the arc-shaped plate (12). One end of the soft conductive connector (22) is riveted to the tail of the rotary connection part of the active contact (3), and the other end is fixed to the conductive rod (23). The neutral point contact (24) is fixed to the end of the conductive rod (23). The neutral point contact (24) and the static contact (11) are respectively in contact connection with the button contact assembly installed in the contact seat (17).

5. The contact system of a 1250A oil-immersed combined on-load tap-changer according to claim 4, characterized in that: The two arc-shaped plates (12) installed in the oil chamber insulating cylinder (21) are respectively fixed in the upper mounting plate and the lower mounting plate through the first connection bolts (31). Through holes corresponding to the rotating shaft (1) are provided in the mounting plate (26). A bearing (32) and a retaining ring (33) are arranged in the through holes. The rotating shaft (1) is rotationally connected to the mounting plate (26) through the bearing (32). The active contact (3), the conductive rod (23) and the neutral point contact (24) are fixedly connected to the upper mounting plate and the lower mounting plate as an integral structure through the second connection bolts (25).

6. The contact system of a 1250A oil-immersed combined on-load tap-changer according to claim 5, characterized in that: The contact support assembly includes a guide sleeve (5), a contact return spring (9), a second pressure plate (10) and a connecting pin. The guide sleeve (5) is installed in the arc-shaped plate (12). The main static contact (4) is installed in the guide sleeve (5). One end of the main static contact (4) is in contact connection with the active contact (3), and the other end is fixed in the arc-shaped plate (12) through a soft connection assembly. The second pressure plate (10) is arranged outside the guide sleeve (5). A connecting pin is provided in the second pressure plate (10). One end of the contact return spring (9) is placed inside the main static contact (4), and the other end is sleeved on the connecting pin in the second pressure plate (10). The contact support assembly is in contact connection with the static contact (11) through the second pressure plate (10).

7. The contact system of a 1250A oil-immersed combined on-load tap-changer according to claim 6, characterized in that: The flexible connection assembly includes a flexible conductive copper sheet (6), a connecting rivet (7), a first pressing plate (8), a gasket (28), a third connecting bolt (29) and a fourth connecting bolt (30). One end of the flexible conductive copper sheet (6) is riveted to the main static contact (4) through the connecting rivet (7) successively passing through the first pressing plate (8) and the flexible conductive copper sheet (6). The middle part of the flexible conductive copper sheet (6) is fixed on the arc-shaped plate (12) by the third connecting bolt (29), and a gasket (28) corresponding to the third connecting bolt (29) is provided on the flexible conductive copper sheet (6). The other end of the flexible conductive copper sheet (6) and both ends of the static contact (11) are fixed on the arc-shaped plate (12) by the fourth connecting bolt (30). During the switching process of the on-load tap-changer with the rotation of the rotating shaft (1), the driving fork (2) drives the active contact (3) to rotate synchronously with the rotating shaft (1). The static contact (11) in the inner contact assembly is pushed outward by the contact reset spring (9) in the contact support assembly, and an avoidance moving space is formed through the flexible conductive copper sheet (6) in the flexible connection assembly, so that the static contact (11) and the neutral point contact (24) in the inner contact assembly are respectively in contact connection with the button contact assembly, constituting a current-carrying loop.

8. A 1250A oil-immersed combined on-load tap-changer contact system according to any one of claims 1 to 6, characterized in that: The button contact assembly includes a button contact (14), a flexible conductive sheet (15), a support member (16), a button reset spring (18) and a fifth connecting bolt (20). The button contact (14) is riveted to the support member (16) through the flexible conductive sheet (15). The button reset spring (18) is arranged inside the support member (16). The support member (16) is snap-fitted inside the contact seat (17). The flexible conductive sheet (15) is fixed on the contact seat (17) by the fifth connecting bolt (20). In the oil chamber insulating cylinder (21), there is an installation hole corresponding to the contact seat (17), and the contact seat (17) is arranged in the oil chamber insulating cylinder (21) through the installation hole. The button contact assembly is in contact connection with the neutral point contact (24) and the static contact (11) through the corresponding button contact (14), and reliable contact is achieved under the action of the button reset spring (18).

9. A 1250A oil-immersed combined on-load tap-changer contact system according to claim 8, characterized in that: The button contact assembly further includes a sealing ring (19). The sealing ring (19) is arranged in the installation hole, and the contact seat (17) is hermetically connected to the oil chamber insulating cylinder (21) through the sealing ring (19).

10. A 1250A oil-immersed combined on-load tap-changer contact system according to claim 8, characterized in that: The button contact assembly is fixedly connected to the contact seat (17) along the vertical direction of the oil chamber insulating cylinder (21). The button contact assemblies installed in the contact seat (17) are respectively single-contact assemblies, double-contact assemblies, and neutral-point contact assemblies. Among them, the single-contact assemblies, double-contact assemblies, and neutral-point contact assemblies are respectively in contact connection with the single static contacts and double static contacts in the static contact (11), and the neutral-point contact (24). The single-contact assemblies in the upper and lower two groups of contact seats (17) located outside the oil chamber insulating cylinder (21) are short-circuited with each other, the double-contact assemblies are short-circuited with each other, and the neutral-point contact assemblies are short-circuited with each other to form a parallel circuit. During the switching process of the on-load tap-changer, the rotating shaft (1) is in contact connection with the button contact assembly through the inner contact assembly to form a single-phase or three-phase 1250A current-carrying circuit.

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