Voltage internal switching device and method suitable for double-voltage transformer

Abstract

The invention provides a voltage internal switching device and method suitable for a double-voltage transformer, and relates to the technical field of electrical setup, two supporting side plates are fixed to one side of the front surface of a mounting base at equal intervals, and a first connecting cable and a second connecting cable are mounted in a first clamp and a second clamp respectively; a supporting frame is fixedly mounted on the front surface of the other side of the mounting base, a third clamp is mounted on the upper surface of the supporting frame, a third connecting cable is mounted in the third clamp, and the third connecting cable is movably connected with the first connecting cable and the second connecting cable through connecting pieces. According to the invention, a movable and lockable shielding cover structure is innovatively designed, during normal operation, a shielding cover is arranged at a terminal connecting part, and when 110kV and 132kV coils are switched to switch the terminal part, a special-shaped electrode formed by irregular metal with an irregular outer surface, such as a bolt, is protected and shielded, so that the electric field distribution is improved, and the operation is convenient.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment technology, specifically to a voltage internal switching device and method suitable for dual-voltage transformers. Background Technology

[0002] During operation, dual-voltage transformers often need to switch their operating voltage according to the power supply network or load requirements;

[0003] For example, patent application CN201220228685.1 discloses a dual-voltage transformer, comprising: a three-phase core structure, three primary windings corresponding to the three-phase core, three secondary windings corresponding to the three-phase core, and a connection switching device. The connection switching device is used to select the interconnection scheme of the three primary windings. Scheme 1 is: connecting the tail ends of the three primary windings together, with the three head ends serving as input terminals; Scheme 2 is: connecting the head and tail ends of the three primary windings to form a closed loop, with the three head ends connected as input terminals. This utility model provides a novel dual-voltage transformer that can achieve 10kV to 20kV conversion through simple connection switching, thus being applicable to 10kV and 20kV power distribution systems, and saving power grid transformation costs in conjunction with grid upgrades.

[0004] The voltage switching operations described above are limited to 10kV and 20kV level conversions. When switching to higher voltages, such as 110kV and 132kV coil conversions, the voltage at the switching terminals is higher. Irregularly shaped electrodes formed by metal on the outer surface of bolts and other components can easily cause electric field distortion, resulting in partial discharge and affecting the safe operation of the equipment. After the internal leads are switched, the connection points are often directly exposed inside the transformer cavity. The transformer operating environment is complex and may be contaminated with oil and dust for a long time. These external factors can easily accumulate at the exposed terminals, leading to oxidation and corrosion of the contact surfaces. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a voltage internal switching device and method suitable for dual-voltage transformers. It solves the problems that connection points are often directly exposed inside the transformer cavity, the transformer operating environment is complex, and oil and dust may accumulate at the exposed terminals, leading to oxidation and corrosion of the contact surfaces. Furthermore, when switching to higher voltages, such as switching between 110kV and 132kV coils, the voltage at the switching terminal is high, and irregularly shaped electrodes formed by irregular metals on the outer surface of bolts and other components can easily cause electric field distortion.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a voltage internal switching device suitable for a dual-voltage transformer, comprising a mounting base, two supporting side plates fixedly fixed at equal intervals on one side of the front surface of the mounting base, four crossbars fixedly installed between the two supporting side plates, and a mounting plate fixedly installed between each pair of crossbars. A first clamp and a second clamp are respectively fixedly installed on the upper surface of the two mounting plates, and a first connecting cable and a second connecting cable are respectively installed inside the first clamp and the second clamp. A support frame is fixedly installed on the other front surface of the mounting base, and a third clamp is installed on the upper surface of the support frame. A third connecting cable is installed inside the third clamp, and the third connecting cable is movably connected to the first connecting cable and the second connecting cable through a connector.

[0007] Preferably, the first connecting cable, the second connecting cable, and the third connecting cable are equipped with terminals, and the terminals are connected to each other by a first connecting bolt.

[0008] Preferably, the protective assembly includes a shield, a first screw sleeve, and a second positioning ring. The shield is fitted over the middle of the first connecting cable, the first screw sleeve is mounted on the first clamp, and the second positioning ring is mounted on the first connecting cable.

[0009] Preferably, a groove is formed on one end surface of the shield, and a first slider is slidably installed inside the groove.

[0010] Preferably, a slide rod is rotatably mounted on the front surface of the first slider, and the slide rod slides through the first clamp.

[0011] Preferably, the slide bar has a threaded section in the middle, which engages with the first threaded sleeve.

[0012] Preferably, a first positioning ring is fixedly installed on the inner wall of the shielding cover. The inner wall of the first positioning ring is provided with an internal thread, and the circumferential surface of the second positioning ring is provided with an external thread. The external thread and the internal thread are engaged and connected.

[0013] Preferably, the shielding cover has a mounting groove on its circumference, and the mounting groove has a through hole on its surface.

[0014] Preferably, a second connecting bolt is installed inside the mounting groove via a second threaded sleeve.

[0015] A voltage switching method suitable for dual-voltage transformers is described below, with the specific operation steps as follows:

[0016] S1. First, ensure the transformer is de-energized, discharged, and properly grounded. Then, use an insulated wrench to loosen the first connecting bolt between the terminals to separate them. At this point, rotate the second connecting bolt to move it upwards, disengaging the tip of the second connecting bolt from the external thread surface, allowing the internal and external threads to rotate.

[0017] S2. At this time, rotate the shielding cover to disengage the internal thread from the external thread, so that the shielding cover is detached from the terminal on the first connecting cable. At the same time, rotate the slide rod to engage the threaded section with the first threaded sleeve, thereby limiting the slide rod and limiting the shielding cover to prevent it from shifting.

[0018] S3. At this time, by rotating the first connecting bolt on the terminal block directly between the third connecting cable and the first connecting cable, the different terminals are separated. Then, rotate the rotatable connector to connect the third connecting cable to the second connecting cable through the connector for replacement.

[0019] S4. After replacement, repeat the above operation to reset the shielding cover to the position of the connector for protection. Then, perform insulation resistance and contact resistance tests on the connection parts. Only after confirming that the connection is reliable and the insulation performance meets the requirements can it be used.

[0020] This invention provides a voltage internal switching device and method suitable for dual-voltage transformers. It has the following beneficial effects:

[0021] 1. By setting up a flexible rotatable connector and first and second connecting cables corresponding to different voltage levels, the present invention enables safe and quick dual voltage switching outside the device without having to enter the transformer box, which greatly reduces safety risks and operational complexity.

[0022] 2. This invention innovatively designs a movable and lockable shielding structure. During normal operation, the shielding completely covers critical connectors and terminals, effectively preventing dust and moisture intrusion and accidental contact, thus improving the equipment's protection level and operational reliability.

[0023] 3. The protective components adopt a double locking method combining threaded connections and anti-loosening bolts, ensuring a firm and reliable fixation. Its sliding rod and slider structure makes the removal and repositioning of the shielding cover simple and controllable, and provides a temporary fixed position after removal, facilitating subsequent switching operations.

[0024] 4. A shielding cover is installed at the terminal connection point. The material is aluminum, and the surface is covered with epoxy resin and paper insulation. When switching the terminal points between 110kV and 132kV coils, it protects and shields irregularly shaped electrodes formed by metals with irregular outer surfaces, such as bolts. This not only improves the electric field distribution and facilitates operation, but also reduces the local electric field intensity, avoids corona discharge and surface flashover, and ensures the insulation safety and operational stability of the equipment. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the overall top structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the first connecting cable structure in this invention;

[0028] Figure 4 This is a schematic cross-sectional view of the shielding cover in this invention;

[0029] Figure 5 This is an enlarged structural diagram of point A in this invention;

[0030] Figure 6 This is an enlarged structural diagram of point B in the present invention.

[0031] The components include: 1. Mounting base; 2. Support side plate; 3. Crossbar; 4. Mounting plate; 5. First clamp; 6. First connecting cable; 7. Protective assembly; 701. Shielding cover; 702. First threaded sleeve; 703. Sliding rod; 704. Threaded section; 705. Sliding groove; 706. Sliding block; 707. First positioning ring; 708. Internal thread; 709. Mounting groove; 710. Second connecting bolt; 711. Second threaded sleeve; 712. Through hole; 713. Second positioning ring; 714. External thread; 8. Second connecting cable; 9. Second clamp; 10. Connector; 11. Support frame; 12. Third clamp; 13. Third connecting cable; 14. Terminal block; 15. First connecting bolt. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figures 1 to 6As shown, this embodiment of the invention provides a voltage internal switching device suitable for dual-voltage transformers, including a mounting base 1. Two support side plates 2 are fixedly fixed at equal intervals on one side of the front surface of the mounting base 1. Four crossbars 3 are fixedly installed between the two support side plates 2. A mounting plate 4 is fixedly installed between every two crossbars 3. A first clamp 5 and a second clamp 9 are fixedly installed on the upper surfaces of the two mounting plates 4, respectively. A first connecting cable 6 and a second connecting cable 8 are respectively installed inside the first clamp 5 and the second clamp 9. A support frame 11 is fixedly installed on the other front surface of the mounting base 1. A third clamp 12 is installed on the upper surface of the support frame 11. A third connecting cable 13 is installed inside the third clamp 12. The third connecting cable 13 is movably connected to the first connecting cable 6 and the second connecting cable 8 through a connector 10.

[0034] like Figures 1 to 6 As shown, terminal blocks 14 are installed at the connection points of the first connecting cable 6, the second connecting cable 8, and the third connecting cable 13, and the terminal blocks 14 are connected to each other by a first connecting bolt 15.

[0035] like Figures 1 to 6As shown, the protective component 7 includes a shielding cover 701, a first threaded sleeve 702, and a second positioning ring 713. The shielding cover 701 is sleeved on the middle of the first connecting cable 6. The first threaded sleeve 702 is disposed on the first clamp 5. The second positioning ring 713 is mounted on the first connecting cable 6. A groove 705 is formed on one end surface of the shielding cover 701. A first slider 706 is slidably installed inside the groove 705. A sliding rod 703 is rotatably installed on the front end surface of the first slider 706. The sliding rod 703 slides through the first clamp 5. A threaded section 704 is provided in the middle of the sliding rod 703. The threaded section 704 engages with the first threaded sleeve 702. A first positioning ring 707 is fixedly installed on the inner wall of the shield 701. The inner wall of the first positioning ring 707 is provided with an internal thread 708. The circumferential surface of the second positioning ring 713 is provided with an external thread 714. The external thread 714 engages with the internal thread 708. The circumferential surface of the shield 701 is provided with a mounting groove 709. A through hole 712 is provided through the surface of the mounting groove 709. A second connecting bolt 710 is installed inside the mounting groove 709 through a second threaded sleeve 711. The operator first performs the safety procedures (power off, discharge, ground). Then, loosen and remove the first connecting bolt 15 on the terminal 14 of the current connection (such as the third connecting cable 13 and the first connecting cable 6). Next, loosen the second connecting bolt 710 on the shield 701. Tighten the shielding cover 701 to separate the first positioning ring 707 from the second positioning ring 713, allowing the shielding cover 701 to be pulled back along the cable axis, fully exposing the internal connector 10 and terminal 14. Simultaneously, rotate the slide rod 703 so that its threaded section 704 engages with the first threaded sleeve 702, temporarily locking the slide rod 703 and the connected shielding cover 701 in the removed position for easy operation. Then, operate the connector 10 to disconnect the terminal 14 of the third connecting cable 13 from the terminal 14 of the first connecting cable 6. Rotate the connector 10 to align the terminal 14 of the third connecting cable 13 with the terminal 14 of the second connecting cable 8, and tighten with the first connecting bolt 15, thus completing the switch from the first voltage level to the second voltage level.

[0036] A voltage switching method suitable for dual-voltage transformers, the specific operation steps are as follows;

[0037] S1. First, ensure that the transformer is de-energized, discharged, and properly grounded. Then, use an insulated wrench to tighten the first connecting bolt 15 between the terminals 14 to separate the terminals 14. At this time, rotate the second connecting bolt 710 to move the second connecting bolt 710 upwards, so that the top of the second connecting bolt 710 disengages from the surface of the external thread 714, allowing the internal thread 708 and the external thread 714 to rotate.

[0038] S2. At this time, rotate the shield 701 to disengage the internal thread 708 from the external thread 714, so that the shield 701 is disengaged from the terminal 14 on the first connecting cable 6. At the same time, rotate the slide rod 703 to engage the threaded section 704 with the first threaded sleeve 702, so that the slide rod 703 is limited and the shield 701 is limited to prevent the shield 701 from shifting.

[0039] S3. At this time, by rotating the first connecting bolt 15 on the terminal 14 directly connecting the third connecting cable 13 and the first connecting cable 6, the different terminals 14 are separated. Then, rotate the rotatable connector 10 to connect the third connecting cable 13 to the second connecting cable 8 through the connector 10 to perform the replacement work.

[0040] S4. After the replacement is completed, repeat the above operation to reset the shield 701 to the position of the connector 10 for protection. Then, perform insulation resistance test and contact resistance test on the connection part. Only after confirming that the connection is reliable and the insulation performance meets the requirements can it be used.

[0041] Working principle:

[0042] When voltage switching is required, the operator first follows the safety procedures (power off, discharge, ground). Then, loosen and remove the first connecting bolt 15 from the terminal 14 of the current connection (e.g., the third connecting cable 13 and the first connecting cable 6). Next, loosen the second connecting bolt 710 on the shield 701. Tighten the shield 701 to separate the first positioning ring 707 from the second positioning ring 713, allowing the shield 701 to be pulled backward along the cable axis, fully exposing the internal connector 10 and terminal 14. Simultaneously, the slide rod 703 can be rotated so that its threaded section 704 engages with the first threaded sleeve 702, temporarily locking the slide rod 703 and the connected shield 701 in the removed position for easy operation. Subsequently, operate the connector 10 to disconnect the terminal 14 of the third connecting cable 13 from the terminal 14 of the first connecting cable 6. Rotate connector 10 to align terminal 14 of the third connecting cable 13 with terminal 14 of the second connecting cable 8, and tighten with first connecting bolt 15. This completes the switch from the first voltage level to the second voltage level. After switching and verifying that everything is correct, reverse the operation: loosen the threaded lock of slide rod 703, push shield 701 back above the connection point, and screw shield 701 to re-thread lock its first positioning ring 707 and second positioning ring 713. Finally, tighten the second connecting bolt 710 to prevent loosening. After restoring protection, perform necessary electrical tests. Only after confirming that the tests are qualified can the cable be put back into operation.

[0043] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A voltage internal switching device suitable for a dual voltage transformer, comprising a mounting base (1), characterized in that, The mounting base (1) is equidistantly fixed with two support side plates (2) on the front surface side, four cross bars (3) are fixedly installed between the two support side plates (2), the mounting plate (4) is fixedly installed between every two cross bars (3), the first clamp (5) and the second clamp (9) are fixedly installed on the upper surfaces of the two mounting plates (4) respectively, the first connecting cable (6) and the second connecting cable (8) are installed in the first clamp (5) and the second clamp (9) respectively, the support frame (11) is fixedly installed on the other side of the front surface of the mounting base (1), the third clamp (12) is installed on the upper surface of the support frame (11), the third connecting cable (13) is installed in the third clamp (12), and the third connecting cable (13) is movably connected with the first connecting cable (6) and the second connecting cable (8) through the connecting piece (10).

2. A voltage internal switching device for a dual voltage transformer according to claim 1, characterized in that, The first connecting cable (6), the second connecting cable (8) and the third connecting cable (13) are provided with wiring terminals (14) at the connection positions, and the wiring terminals (14) are connected through the first connecting bolt (15).

3. A voltage internal switching device for a dual voltage transformer according to claim 1, characterized in that, The protection assembly (7) comprises a shielding cover (701), a first screw sleeve (702) and a second positioning ring (713), the shielding cover (701) is sleeved on the middle part of the first connecting cable (6), the first screw sleeve (702) is arranged on the first clamp (5), and the second positioning ring (713) is installed on the first connecting cable (6).

4. A voltage internal switching device for a dual voltage transformer according to claim 3, characterized in that, A sliding groove (705) is formed in one end surface of the shielding cover (701), and a first sliding block (706) is slidably installed in the sliding groove (705).

5. A voltage internal switching device for a dual voltage transformer according to claim 4, characterized in that, A sliding rod (703) is rotatably installed on the front end surface of the first sliding block (706), and the sliding rod (703) slidably penetrates the first clamp (5).

6. A voltage internal switching device for a dual voltage transformer according to claim 5, characterized in that, A threaded section (704) is arranged on the middle part of the sliding rod (703), and the threaded section (704) is in meshing connection with the first screw sleeve (702).

7. A voltage internal switching device for a dual voltage transformer according to claim 6, characterized in that A first positioning ring (707) is fixedly installed on the inner wall of the shielding cover (701), an inner thread (708) is arranged on the inner wall of the first positioning ring (707), an outer thread (714) is arranged on the circumferential surface of the second positioning ring (713), and the outer thread (714) is in meshing connection with the inner thread (708).

8. A voltage internal switching device for a dual voltage transformer according to claim 7, characterized in that, An installation groove (709) is formed in the circumferential surface of the shielding cover (701), and a perforation (712) is formed in the surface of the installation groove (709).

9. A voltage internal switching device for a dual voltage transformer according to claim 8, characterized in that, A second connecting bolt (710) is installed in the installation groove (709) through a second screw sleeve (711).

10. A voltage internal switching method for a dual voltage transformer according to claim 9, characterized in that, The specific operation steps are as follows, S1, first of all, ensure that the transformer has been powered off, discharged and well grounded, then use an insulating wrench to twist the first connecting bolt (15) between the wiring terminals (14), so that the wiring terminals (14) are separated, at this time, the second connecting bolt (710) is rotated, so that the second connecting bolt (710) moves upward in cooperation with the second connecting bolt (710), so that the top end of the second connecting bolt (710) is separated from the surface of the outer thread (714), so that the inner thread (708) and the outer thread (714) can be rotated; S2, at this time rotate the shield (701), the inner thread (708) and the outer thread (714) are separated, the shield (701) is separated from the terminal (14) on the first connecting cable (6), and the slide rod (703) is rotated, the threaded section (704) is engaged with the first sleeve (702), the slide rod (703) is limited, the shield (701) can be limited, and the shield (701) is prevented from deviating; S3, at this time, rotate the first connecting bolt (15) on the terminal (14) of the third connecting cable (13) and the first connecting cable (6), separate the different terminals (14), rotate the rotatable connecting piece (10), connect the third connecting cable (13) and the second connecting cable (8) through the connecting piece (10), and replace the connecting cable (13); S4, after replacement, the shield (701) is reset to the position of the connecting piece (10) for protection, and then the insulation resistance test and the contact resistance test are carried out on the connecting part, and the connection is reliable, the insulation performance meets the requirements, and then it can be used.

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