Vacuum circuit breaker with contact electromagnetic shield

Abstract

The utility model provides a kind of vacuum circuit breaker with contact electromagnetic shield, including support frame, insulating beam, upper branch row, lower branch row, grounding row, driving mechanism, moving contact, connecting static contact and vacuum arc-extinguishing chamber;The insulating beam is erected on support frame, and upper branch row is arranged on insulating beam;Lower branch row is arranged in support frame;The hinged end of moving contact is hinged on connecting static contact;Connecting static contact is connected with lower branch row by vacuum arc-extinguishing chamber;Moving contact is connected with driving mechanism, to realize the swing of the movable end of moving contact to with upper branch row closing, or swing to with grounding row closing;The movable end of moving contact is respectively provided with shield case on both sides;The side of shield case that is attached to moving contact forms attachment surface, and more than one cavity is formed on attachment surface.The circuit breaker can limit high-frequency current in shield case, effectively reduce electromagnetic radiation interference, improve the reliability and safety of equipment.

Description

Technical Field

[0001] This utility model relates to the field of electrical equipment technology, and more specifically, to a vacuum circuit breaker with contact electromagnetic shielding. Background Technology

[0002] Medium-voltage gas-insulated metal-enclosed switchgear is designed to completely seal high-voltage energized components (such as circuit breakers, disconnectors, grounding switches, busbars, and connecting terminals) within an airtight enclosure welded from stainless steel or aluminum alloy. The chamber is filled with a pressurized insulating gas, which replaces the air in traditional air-insulated switchgear as the primary insulating medium and the arc-extinguishing medium during circuit breaker interruption. This type of equipment offers advantages such as miniaturization and compactness, high reliability, high safety, and strong adaptability.

[0003] Medium-voltage gas-insulated metal-enclosed switchgear, as a type of fully metal-enclosed, gas-insulated switchgear, possesses excellent electromagnetic shielding performance. During circuit breaker opening and closing, the separation / contact between the moving and stationary contacts generates high-intensity transient electromagnetic fields (frequency bands reaching MHz-GHz), producing electromagnetic radiation interference. This transient electromagnetic interference poses a risk of overvoltage breakdown or may affect nearby low-voltage equipment (such as communication and control signals). Therefore, the design of switchgear needs to strengthen the shielding against transient electromagnetic radiation interference from circuit breaker opening and closing. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and provide a vacuum circuit breaker with electromagnetic shielding of contacts. This circuit breaker can limit high-frequency current within the shielding cover, effectively reduce electromagnetic radiation interference, and improve the reliability and safety of the equipment.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution: a vacuum circuit breaker with contact electromagnetic shielding, comprising a support frame, an insulating beam, an upper branch line, a lower branch line, a grounding bar, a drive mechanism, a moving contact, a connecting stationary contact, and a vacuum interrupter; the insulating beam is mounted on the support frame, and the upper branch line is arranged on the insulating beam; the lower branch line is disposed on the support frame; the hinged end of the moving contact is hinged to the connecting stationary contact; the connecting stationary contact is connected to the lower branch line through the vacuum interrupter; the moving contact is connected to the drive mechanism to realize that the movable end of the moving contact swings to close with the upper branch line, or swings to close with the grounding bar; shielding covers are respectively provided on both sides of the movable end of the moving contact; the shielding cover is attached to one side of the moving contact to form a contact surface, and one or more cavities are opened on the contact surface.

[0006] The key location of transient electromagnetic radiation during circuit breaker opening and closing lies at the circuit breaker contact point. Steep-front overvoltages and rapidly changing currents generated at the contact point, along with the interaction of parasitic inductance and capacitance on the conductors with the rapidly changing voltage / current, amplify interference and generate local oscillations. Therefore, this invention incorporates a shielding cover at the circuit breaker contact point, specifically at the moving end of the moving contact. This shielding cover generates eddy currents to counteract the high-frequency magnetic field generated by sudden current changes, confining the high-frequency current within the cover. This effectively reduces electromagnetic radiation interference and improves the reliability and safety of the equipment. The shielding cover is directly mounted on both sides of the moving contact, allowing it to swing in conjunction with the contact. Its simple structure ensures shielding functionality during both opening and closing.

[0007] Preferably, the shield is elongated; the width of the shield is greater than the width of the moving contact, and the length of the shield extends from the edge of the moving end of the moving contact to the connection with the drive mechanism, so as to completely cover the outer side area between the edge of the moving end of the moving contact and the connection with the drive mechanism.

[0008] Preferably, the shielding cover is provided with a countersunk hole for installing a fixing connector; the shielding covers on both sides are positioned with the moving contact by pins and fixed to the moving contact by the fixing connector.

[0009] Preferably, when there are two or more cavities on the bonding surface, the cavities are arranged side by side along the length of the shield.

[0010] Preferably, shielding rings are provided on both sides of the hinge end of the moving contact. The shielding rings can further enhance the shielding of electromagnetic radiation, and further improve the reliability and safety of the equipment.

[0011] Preferably, the center of the shielding ring is coaxially arranged with the hinge center of the moving contact and the connecting stationary contact; the radius of the shielding ring is greater than the distance between the hinge center and the edge of the hinge end of the moving contact, so that the shielding ring completely covers the outer surface area between the edge of the hinge end of the moving contact and the hinge point with the connecting stationary contact.

[0012] Preferably, the shielding ring is provided with a countersunk hole for installing the fixing connector; the two shielding rings on both sides are fixed to the moving contact through the fixing connector.

[0013] Preferably, the driving mechanism includes a drive shaft, a driving device for rotating the drive shaft, a drive crank arm, a connecting rod, and a connecting block; the drive crank arm passes through the drive shaft; one end of the connecting rod is hinged to the drive crank arm, and the other end of the connecting rod is hinged to the connecting block; the connecting block is connected to the moving contact.

[0014] Preferably, the upper branch has an isolating stationary contact for closing with the moving end of the moving contact; the grounding bar is disposed in the support frame; the grounding bar has a grounding contact for closing with the moving end of the moving contact.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. This utility model provides a shielding cover at the circuit breaker break point. The shielding cover can generate eddy currents to counteract the high-frequency magnetic field generated by the sudden change in current, effectively reducing electromagnetic radiation interference and improving the reliability and safety of the equipment. 2. In this utility model, the shielding cover is directly installed on both sides of the moving contact, which can be used in conjunction with the swing of the moving contact to achieve the shielding function at the moment of opening and closing; 3. In this utility model, the moving contact is also equipped with a shielding ring, which can further enhance the shielding of electromagnetic radiation and further improve the reliability and safety of the equipment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the vacuum circuit breaker with contact electromagnetic shielding of this utility model in the isolated closing state; Figure 2 This is a schematic diagram of the structure of the vacuum circuit breaker with contact electromagnetic shielding hidden support frame side plate of this utility model; Figure 3 This is a schematic diagram showing the connection of the moving contact, shielding cover, shielding ring, and connecting stationary contact in the vacuum circuit breaker with electromagnetic shielding of the contacts of this utility model. Figure 4 This is an exploded view of the moving contact, shielding cover, and shielding ring of the vacuum circuit breaker with electromagnetic shielding of the present invention. Figure 5 This is a schematic diagram of the vacuum circuit breaker with contact electromagnetic shielding of this utility model in the grounded closed state; Among them, 1 is the insulating beam, 2 is the isolating stationary contact, 3 is the upper branch, 4 is the driving crank arm, 5 is the connecting rod, 6 is the shielding ring, 6.1 is the second countersunk hole, 7 is the connecting block, 8 is the shielding cover, 8.1 is the first countersunk hole, 8.2 is the cavity, 9 is the grounding contact, 10 is the first fixed connector, 11 is the moving contact, 12 is the connecting stationary contact, 13 is the lower branch, 14 is the vacuum interrupter, 15 is the grounding bar, 16 is the contact seat, 17 is the support frame, and 18 is the drive shaft. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] Example like Figures 1 to 5As shown, this embodiment of a vacuum circuit breaker with electromagnetic shielding includes a support frame 17, an insulating beam 1, an upper branch line 3, a lower branch line 13, a grounding busbar 15, a drive mechanism, a moving contact 11, a connecting stationary contact 12, and a vacuum interrupter 14. The insulating beam 1 is mounted on the support frame 17, and the upper branch line 3 is arranged on the insulating beam 1; the upper branch line 3 has an isolating stationary contact 2 for closing with the moving end of the moving contact 11. The lower branch line 13 is disposed on the support frame 17. The grounding busbar 15 is disposed in the support frame 17; the grounding busbar 15 has a grounding contact 9 for closing with the moving end of the moving contact 11. The hinged end of the moving contact 11 is hinged to the connecting stationary contact 12; the connecting stationary contact 12 is connected to the lower branch line 13 through the vacuum interrupter 14.

[0019] The moving contact 11 is connected to the drive mechanism. Specifically, the drive mechanism includes a drive shaft 18, a drive device for rotating the drive shaft 18, a drive crank arm 4, a connecting rod 5, and a connecting block 7; the drive crank arm 4 passes through the drive shaft 18; one end of the connecting rod 5 is hinged to the drive crank arm 4, and the other end of the connecting rod 5 is hinged to the connecting block 7; the connecting block 7 is connected to the moving contact 11.

[0020] With the movable end of the moving contact 11 closed to the grounding busbar 15, the drive shaft 18, driven by the drive device, rotates 80° clockwise, causing the drive crank arm 4 to rotate clockwise around the center, thereby moving the connecting rod 5 to the right. This, in turn, causes the moving contact 11 to rotate clockwise around the hinge center, leaving the movable end of the moving contact 11 suspended, completing the grounding tripping action. The drive shaft 18, driven by the drive device, continues to rotate 85° clockwise, repeating the above action, closing the movable end of the moving contact 11 with the upper branch busbar 3, completing the isolation tripping action. Conversely, the drive shaft 18, driven by the drive device, rotates 85° counterclockwise, leaving the movable end of the moving contact 11 suspended, completing the isolation tripping action; the drive shaft 18, driven by the drive device, continues to rotate 80° counterclockwise, closing the movable end of the moving contact 11 with the grounding busbar 15, completing the grounding tripping action.

[0021] A shielding cover 8 is provided on both sides of the movable end of the moving contact 11; the shielding cover 8 is attached to one side of the moving contact 11 to form a contact surface, and one or more cavities 8.2 are formed on the contact surface. In this embodiment, there are two cavities; in actual applications, there may be one, three, or even more cavities. When there are two or more cavities 8.2, the cavities 8.2 are arranged side by side along the length of the shielding cover 8.

[0022] The shield 8 is elongated; the width of the shield 8 is greater than the width of the moving contact 11, and the length of the shield 8 extends from the edge of the moving end of the moving contact 11 to the connection with the drive mechanism, that is, to the connection with the connecting block 7; the shield 8 completely covers the outer side area between the edge of the moving end of the moving contact 11 and the connection with the drive mechanism.

[0023] The shielding cover 8 is provided with a countersunk hole 8.1 for installing the fixing connector 10; the shielding covers 8 on both sides are positioned with the moving contact 11 by pins and fixed with the moving contact 11 by the fixing connector 10.

[0024] The key location of transient electromagnetic radiation during circuit breaker opening and closing lies at the circuit breaker contact point. Steep-front overvoltages and rapidly changing currents generated at the contact point, along with the interaction between parasitic inductance and capacitance on the conductors and the rapidly changing voltage / current, amplify interference and generate local oscillations. Therefore, this invention provides a shielding cover 8 at the circuit breaker contact point, i.e., the moving end of the moving contact 11. The shielding cover 8 generates eddy currents to counteract the high-frequency magnetic field generated by the current surge, confining the high-frequency current within the shielding cover 8. This effectively reduces electromagnetic radiation interference and improves the reliability and safety of the equipment. The shielding cover 8 is directly installed on both sides of the moving contact 11 and can swing in conjunction with the moving contact 11. Its simple structure allows it to provide shielding during both opening and closing.

[0025] Preferably, shielding rings 6 are provided on both sides of the hinge end of the moving contact 11. The center of the shielding ring 6 is coaxially arranged with the hinge center of the moving contact 11 and the connecting stationary contact 12; the radius of the shielding ring 6 is greater than the distance between the hinge center and the edge of the hinge end of the moving contact 11, so that the shielding ring 6 completely shields the outer surface area from the edge of the hinge end of the moving contact 11 to the hinge point with the connecting stationary contact 12. The shielding ring 6 is provided with a countersunk hole 6.1 for installing the second fixing connector; the two shielding rings 6 are fixed to the moving contact 11 by the second fixing connector.

[0026] The shielding ring 6 can further enhance the shielding of electromagnetic radiation, thereby further improving the reliability and safety of the equipment.

[0027] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A vacuum circuit breaker with contact electromagnetic shielding, characterized by: The device includes a support frame, an insulating beam, an upper branch line, a lower branch line, a grounding bar, a drive mechanism, a moving contact, a connecting stationary contact, and a vacuum interrupter. The insulating beam is mounted on the support frame, and the upper branch line is arranged on the insulating beam. The lower branch line is mounted on the support frame. The hinged end of the moving contact is hinged to the connecting stationary contact. The connecting stationary contact is connected to the lower branch line through the vacuum interrupter. The moving contact is connected to the drive mechanism to allow the movable end of the moving contact to swing to close with the upper branch line or to close with the grounding bar. Shielding covers are provided on both sides of the movable end of the moving contact. The shielding covers are attached to one side of the moving contact to form a contact surface, and one or more cavities are opened on the contact surface.

2. The vacuum circuit breaker with contact electromagnetic shield according to claim 1, characterized in that: The shield is elongated; the width of the shield is greater than the width of the moving contact, and the length of the shield extends from the edge of the moving end of the moving contact to the connection with the drive mechanism, so that the shield completely covers the outer side area between the edge of the moving end of the moving contact and the connection with the drive mechanism.

3. The vacuum circuit breaker with contact electromagnetic shielding according to claim 2, characterized in that: The shielding cover is provided with a countersunk hole for installing a fixing connector; the shielding covers on both sides are positioned with the moving contact by pins and fixed to the moving contact by the fixing connector.

4. The vacuum circuit breaker with contact electromagnetic shielding according to claim 1, characterized in that: When there are two or more cavities on the bonding surface, the cavities are arranged side by side along the length of the shield.

5. The vacuum circuit breaker with contact electromagnetic shielding according to claim 1, characterized in that: The hinge end of the moving contact is provided with shielding rings on both sides.

6. The vacuum circuit breaker with contact electromagnetic shielding according to claim 5, characterized in that: The center of the shielding ring is coaxially arranged with the hinge center of the moving contact and the connecting stationary contact; the radius of the shielding ring is greater than the distance between the hinge center and the edge of the hinge end of the moving contact, so that the shielding ring completely covers the outer surface area between the edge of the hinge end of the moving contact and the hinge point with the connecting stationary contact.

7. The vacuum circuit breaker with contact electromagnetic shielding according to claim 6, characterized in that: The shielding ring is provided with a countersunk hole for installing the second fixing connector; the shielding rings on both sides are fixed to the moving contact through the second fixing connector.

8. The vacuum circuit breaker with contact electromagnetic shielding according to claim 1, characterized in that: The driving mechanism includes a drive shaft, a driving device for rotating the drive shaft, a drive crank arm, a connecting rod, and a connecting block; the drive crank arm passes through the drive shaft; one end of the connecting rod is hinged to the drive crank arm, and the other end of the connecting rod is hinged to the connecting block; the connecting block is connected to the moving contact.

9. The vacuum circuit breaker with contact electromagnetic shielding according to claim 1, characterized in that: The upper branch has an isolating stationary contact for closing with the moving end of the moving contact; the grounding bar is installed in the support frame; the grounding bar has a grounding contact for closing with the moving end of the moving contact.

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