Vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity

Abstract

The invention discloses a vacuum arc extinguish chamber structure with large rated current and strong breaking capacity, which comprises a structure body, and is characterized in that the structure body comprises a static contact assembly, the static contact assembly comprises a static end arc contact and a static end main contact, and the static end arc contact is arranged in front of the static end main contact and protrudes for a preset distance d along the on-off direction; and the moving contact assembly comprises a moving end main contact and a moving end arc contact, and the moving end main contact and the moving end arc contact are located on the same plane. According to the invention, the effect that the main contact does not burn arc during breaking is realized, the contact surface of the main contact is protected from being ablated by the arc, and a physical foundation is laid for the high capacity of the vacuum arc-extinguishing chamber. The moving end arc contact is provided with a coil structure so as to generate a transverse magnetic field or a longitudinal magnetic field, and the magnetic lines of force between the static end arc contact and the moving end arc contact have the combined action of the longitudinal magnetic field and the transverse magnetic field, so that the breaking capacity is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum arc-extinguishing chamber, and particularly relates to a vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity. BACKGROUND

[0002] Vacuum circuit breakers are widely used in 10kV and 35kV systems due to many advantages. However, the vacuum circuit breaker uses flat plate contacts due to the structure of the contacts, and the flat plate contacts are connected with longitudinal magnetic or transverse magnetic contact structures behind the flat plate. Although pressure is applied to the flat plate contacts, the contact surfaces are inevitably ablated due to arc during multiple breaking, so that the contact resistance is continuously increased. During normal current flow, the temperature rise is increased, so that the current carrying capacity of the vacuum circuit breaker is limited.

[0003] The existing vacuum arc-extinguishing chamber adopts a single contact structure, and the arc is generated between the same contacts during closing and breaking, which causes serious contact ablation and increases the contact resistance. Some improved schemes attempt to add auxiliary contacts, but the following problems exist:

[0004] The breaking action timing is difficult to accurately control;

[0005] The uneven electric field distribution of the double breaking points affects the arc-extinguishing performance;

[0006] The main contact may still be affected by the arc.

[0007] The present application solves the above problems through the design of split contact, spring pre-pressing mechanism and the synergistic effect of magnetic field.

[0008] As described above, the present application provides a vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity to solve the above problems. SUMMARY

[0009] The present application aims to solve the problems in the prior art and provides a vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity.

[0010] To achieve the above purpose, the present application adopts the following technical scheme:

[0011] A vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity comprises a structure body, wherein the structure body comprises:

[0012] A static contact assembly comprises a static arc contact and a static main contact, and the static arc contact is arranged in front of the static main contact and protrudes in the on-off direction by a preset distance d;

[0013] The moving contact assembly comprises a moving end main contact and a moving end arc contact, which are in the same plane, and the static end arc contact is used to first contact the moving end arc contact when closed and to last break the arc when breaking, so as to realize the arc burning between the arc contacts;

[0014] A vacuum insulation shell is in airtight connection with the static contact assembly at one end and is connected with the moving contact assembly through a bellows at the other end, so as to form a closed vacuum cavity;

[0015] The bellows is used to ensure that the moving contact assembly maintains the vacuum degree of the cavity during reciprocating motion, and the bellows shield is used to adjust the electric field distribution in the arc-extinguishing chamber;

[0016] The static end main contact and the moving end main contact constitute a main current flow path for current transmission in a normal current flow state.

[0017] The static end arc contact and the moving end arc contact constitute an arc burning path for generating and extinguishing an arc during breaking.

[0018] The static end arc contact is made of copper-chromium alloy material, and the moving end main contact is made of red copper material and plated with silver on the contact surface to enhance the conductivity and corrosion resistance.

[0019] Preferably, the static contact assembly comprises a hollow copper conductive rod, a compression spring is arranged inside the copper conductive rod, and wear-resistant guide sleeves are installed at both ends of the copper conductive rod, which cooperate with the copper conductive rod to limit the linear motion of the copper conductive rod in the on-off direction.

[0020] Preferably, the static end arc contact is fixedly connected with the hollow copper conductive rod through a connecting piece, the connecting piece comprises a connecting nut and an extended contact piece with a threaded hole, and the connecting structure enables the static end arc contact to produce a pre-displacement relative to the static end main contact under the action of the compression spring.

[0021] Preferably, the moving end arc contact is connected with an arc-extinguishing coil through riveting or welding, the arc-extinguishing coil is in a longitudinal magnetic or transverse magnetic structure, and is used to enhance the arc burning magnetic field to improve the arc extinguishing capability when energized.

[0022] Preferably, the moving contact assembly further comprises a moving conductive rod and a moving conductive rod guide sleeve, the moving conductive rod is electrically connected with the moving end main contact, and the conductive rod guide sleeve is used to ensure the motion stability of the moving conductive rod during the on-off process.

[0023] Preferably, the bellows shield is made of red copper material, and the shape and length are used to uniformly distribute the electric field inside the vacuum arc-extinguishing chamber.

[0024] Preferably, during the closing process, the moving end arc contact and the static end arc contact first contact to form an arc channel QF2, and then the moving end main contact and the static end main contact are closed to form a main current path QF1.

[0025] During the breaking process, the moving end main contact and the static end main contact are first disconnected, the moving end arc contact and the static end arc contact continue to maintain the arc until the last disconnection, and the main contact does not generate an arc during the whole process.

[0026] Preferably, the closing time difference between the arc contacts is adjusted by the distance d and the static end spring pre-pressing to realize the sequential control of the on-off operation.

[0027] Preferably, the structure of the static end arc contact is in a circular arc shape, a middle flat plate shape or a structure with a tangent edge circular arc and a flat plate, which satisfies the design principle of uniform electric field distribution between the contacts during the on-off.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1. The structure of the moving and static contacts of the vacuum arc chamber is modified, and instead of the previous flat plate contacts, there are arc contacts and main contacts respectively.

[0030] 2. The effect of two breaking points is realized in one vacuum arc chamber.

[0031] 3. The gap formed by the arc contacts and the gap formed by the main contacts have a time difference during the closing, and the arc formed between the arc contacts protects the main contacts from the ablation of the arc during the closing, which lays a foundation for the small contact resistance of the main contacts in the closed state.

[0032] 4. The gap formed by the arc contacts and the gap formed by the main contacts have a time difference during the breaking, and the arc formed between the arc contacts protects the main contacts from the arc during the breaking, which realizes the effect of no arc of the main contacts during the breaking and lays a foundation for the small contact resistance of the main contacts in the closed state.

[0033] The present application protects the main contacts from the ablation of the arc by the arc formed between the arc contacts during the closing, which lays a foundation for the small contact resistance of the main contacts in the closed state, and only the arc formed between the arc contacts protects the main contacts from the arc during the breaking, which realizes the effect of no arc of the main contacts during the breaking, protects the contact surface of the main contacts from the ablation of the arc and lays a physical foundation for the large capacity of the vacuum arc chamber. The moving end arc contact itself has a coil structure to generate a transverse magnetic field or a longitudinal magnetic field, and the magnetic lines between the static end arc contact and the moving end arc contact have the comprehensive effect of the longitudinal magnetic field and the transverse magnetic field, so the breaking capacity is strong. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1A schematic structural view of a vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity is provided in the present application.

[0035] Figure 2 An internal structural view of a hollow copper conductor of the vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity is provided in the present application.

[0036] Figure 3 A dynamic end structural view of a main contact and an arc contact of the vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity is provided in the present application.

[0037] Figure 4 A whole structural view and a component view of the vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity is provided in the present application.

[0038] Figure 5 A connection relationship view between a fracture formed by an arc contact and a fracture formed by a main contact of the vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity is provided in the present application.

[0039] Figure 6 An example view of different shapes of static end arc contacts of the vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity is provided in the present application.

[0040] In the figure, 1 is a static end arc contact, 2 is a static end main contact, 3 is a dynamic end main contact, 4 is a dynamic end arc contact, 5 is a corrugated tube shielding cover, 6 is a corrugated tube, 7 is a copper conducting rod, 8 is a compression spring, 9 is a dynamic conducting rod, and 10 is a dynamic conducting rod guide sleeve. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0042] EMBODIMENT

[0043] REFERENCE Figures 1-6 A vacuum arc-extinguishing chamber structure with large rated current and strong breaking capacity includes a structural body, which comprises:

[0044] A static contact assembly, which comprises a static end arc contact 1 and a static end main contact 2, the static end arc contact 1 being arranged in front of the static end main contact 2 and protruding a preset distance d along a make-break direction;

[0045] A dynamic contact assembly, which comprises a dynamic end main contact 3 and a dynamic end arc contact 4, the dynamic end main contact 3 and the dynamic end arc contact 4 being in the same plane, the static end arc contact 1 being used to first contact the dynamic end arc contact 4 when closed and to be disconnected last when broken, so as to realize arc burning between the arc contacts;

[0046] a vacuum insulation shell, one end of which is in airtight connection with the static contact assembly, and the other end is connected with the dynamic contact assembly through a bellows, forming a closed vacuum cavity;

[0047] a bellows 6 for ensuring that the dynamic contact assembly maintains the vacuum degree of the cavity during reciprocating motion, and a bellows shield 5 for adjusting the electric field distribution inside the vacuum arc chamber;

[0048] The static end main contact 2 and the dynamic end main contact 3 constitute a main current path for current transmission in a normal current passing state.

[0049] The static end arc contact 1 and the dynamic end arc contact 4 constitute an arc path for generating and extinguishing an arc during breaking.

[0050] The static end arc contact 1 is made of copper-chromium alloy material, and the dynamic end main contact 3 is made of red copper material and plated with silver on its contact surface to enhance the conductivity and corrosion resistance.

[0051] More specifically, the static contact assembly includes a hollow copper conducting rod 7, a compression spring 8 is arranged inside the copper conducting rod 7, wear-resistant guide sleeves are installed at both ends of the copper conducting rod 7, and the guide sleeves cooperate with the copper conducting rod 7 to limit the linear motion of the copper conducting rod 7 in the on-off direction. The static end arc contact 1 is fixedly connected with the hollow copper conducting rod 7 through a connecting piece, the connecting piece includes a connecting nut and an extended contact piece with a threaded hole, and the connecting structure enables the static end arc contact 1 to produce a pre-displacement relative to the static end main contact 2 under the action of the compression spring 8.

[0052] The dynamic end arc contact 4 is connected with the arc extinguishing coil through riveting or welding, the arc extinguishing coil is in longitudinal or transverse magnetic structure, and is used for enhancing the arc magnetic field to improve the arc extinguishing capacity when energized. The dynamic contact assembly further includes a dynamic conducting rod 9 and a dynamic conducting rod guide sleeve 10, the dynamic conducting rod 9 is electrically connected with the dynamic end main contact 3, and the conducting rod guide sleeve 10 is used to ensure the motion stability of the dynamic conducting rod 9 during the on-off process.

[0053] More specifically, the bellows shield 5 is made of red copper material, and the shape and length are used to uniformly distribute the electric field inside the vacuum arc chamber.

[0054] During the closing process, the dynamic end arc contact 4 first contacts the static end arc contact 1 to form an arc passage QF2, and then the dynamic end main contact 3 and the static end main contact 2 are closed to form a main current path QF1.

[0055] In the breaking process, the moving end main contact 3 and the static end main contact 2 are first disconnected, the moving end arc contact 4 and the static end arc contact 1 continue to maintain the arc, and are finally disconnected, and the main contact does not generate arc during the whole process, the closing time difference between the arc contacts is adjusted by the distance d and the static end spring pre-pressing, so as to realize the sequential control of the on-off operation, and the structure of the static end arc contact 1 is in the shape of a circular arc, a middle flat plate or a tangent structure of an edge circular arc and a flat plate, which meets the design principle of uniform electric field distribution between the contacts during on-off.

[0056] It should be noted that, Figure 1 The static end structure of the novel vacuum interrupter composed of the main contact and the arc contact

[0057] The arc contact of the static contact is in the shape of a circular arc, which protrudes from the main contact of the static contact by a certain distance d. The arc contact of the static contact is made of copper-chromium contact material, which is not only resistant to arc but also has good arc breaking performance. The part with the label 5 of the static contact is in the shape of a circular arc, and the part with the label 6 is in the shape of a hollow copper conductor. Figure 1 The part with the label 8 is a wear-resistant guide sleeve. Figure 1 The internal structure of the hollow copper conductor with the label 6 is shown in Figure 2 The part with the label A of the hollow copper conductor is provided with Figure 2 The wear-resistant guide sleeve with the label 12. Figure 1 The cylindrical surface with the label B is connected with the watchband contact guide body with the label 3 after being plated with silver. Figure 2 The surface with the label C is plated with silver, so that the silver-plated surface is closely connected with the arc contact with the label 1 of the vacuum interrupter shown in Figure 1 Figure 2 Figure 1

[0058] Figure 2 Figure 1 The internal structure of the hollow copper conductor with the label 6

[0059] The moving end structure of the novel vacuum interrupter is shown in Figure 3

[0060] The arc contact and the main contact of the moving contact are both in the shape of a flat plate, and the main contact body is made of red copper, and the side surface is plated with silver to enhance the conductivity.

[0061] Figure 3 The moving end structure of the novel vacuum interrupter composed of the main contact and the arc contact

[0062] The vacuum interrupter of the whole vacuum circuit breaker is shown in Figure 4 Figure 4 ​​​​​The A of the new vacuum interrupter is a microcrystalline glass or ceramic insulation shell. It is connected with the static end and the moving end respectively. It is connected with the corrugated tube of the moving end on one side, so that the moving end ensures the vacuum degree in the vacuum interrupter while moving. It is connected with the metal primary forming of the static end on the other side, which ensures the vacuum degree in the vacuum interrupter. The B is a corrugated tube shielding cover made of red copper. Its shape and length are used to adjust the electric field distribution in the vacuum interrupter, so that the electric field distribution in the whole vacuum interrupter is uniform at the breaking position of the moving contact part and the static contact part. Figure 4 The main components of the new vacuum interrupter shown include: a static contact part composed of a main contact and an arc contact; a moving contact part composed of a main contact and an arc contact; a corrugated tube and a corrugated tube shielding cover.

[0063] Figure 4 The overall structure and component diagram of the new vacuum interrupter

[0064] The mechanical operating mechanism for moving the moving contact and the moving conducting rod of the new vacuum interrupter provides operating power, and the movement of the moving contact makes the vacuum interrupter realize closing and breaking. When the new vacuum interrupter starts to close from the open state, the moving contact moves to a certain position, and the distance between the protruding arc contacts of the moving contact and the static contact cannot withstand the voltage of the power source applied to the gap, so the gap is first broken down, and the arc starts to burn between the arc contacts of the static end and the arc contacts of the moving end. Figure 5 QF2 is the break between the arc contacts of the moving end and the arc contacts of the static end of the new vacuum interrupter. QF1 is the break between the static contacts of the moving end and the static contacts of the static end of the new vacuum interrupter.

[0065] Figure 5 The connection relationship between the break formed by the arc contacts and the break formed by the main contacts of the new vacuum interrupter

[0066] When the spring of the static end is in a free state, the distance between the arc contacts of the static end and the arc contacts of the moving end and the main contacts of the moving end under the action of the spring is smaller than the distance between the main contacts of the static end and the main contacts of the moving end by a distance d, as shown in the figure. Figure 4 In this way, QF2 in Figure 5 precedes QF1 in closing when closing. The time saved by QF2 is related to the distance d, and the adjustment Figure 4The shape of the moving end and the static end main contact can further adjust the time difference of the action of QF2 and QF1. QF2 realizes the function of closing from the beginning of pre-breakdown. The moving end continues to move under the pushing of the operating mechanism, and the spring inside the arc contact of the static end is compressed. The main contact of the moving end and the main contact of the static end are in contact under the action of the finger spring, so that QF1 is closed. The contacts of QF1 never arc, so the contact surface condition is good, the contact is good, the conductivity is good, and the contact resistance is small, so the heating of the contacts of the circuit breaker under normal closing condition is small.

[0067] When the new type of vacuum circuit breaker needs to be opened, QF1 is separated before QF2, at this time QF2 is still in the closed state, so that QF1 does not arc during breaking. QF1 does not arc during closing and breaking, so the contact surface is not ablated by arc, the surface condition is good, and the contact resistance is small under normal current carrying. In this way, the arc is limited between the contacts of QF2 during opening, which protects the contacts of QF1 from arcing, so that the contact resistance is small under closing condition. The arcing contact has good arc extinguishing performance, and the magnetic field acts, so the arc extinguishing capability of the circuit breaker is ensured.

[0068] The innovation points of the patent are summarized as follows:

[0069] (1) The structure of the moving and static contacts of the vacuum arc chamber is modified, which is no longer the previous flat plate contact, but has arc contacts and main contacts respectively;

[0070] (2) The effect of two breaking points is realized in one vacuum arc chamber;

[0071] (3) The gap formed by the arc contact and the gap formed by the main contact have a time difference during closing. The arc formed by the arc contact protects the main contact from arc ablation during closing, which lays the foundation for the small contact resistance of the main contact under closing condition;

[0072] (4) The gap formed by the arc contact and the gap formed by the main contact have a time difference during breaking. The arc formed by the arc contact protects the main contact from arcing during breaking, which realizes the effect of no arcing of the main contact during breaking, and lays the foundation for the small contact resistance of the main contact under closing condition;

[0073] Such a new type of vacuum arc chamber structure is the first of its kind.

[0074] Figure 6 Examples of different shapes of static end arc contacts

[0075] In addition, the coil structure for generating longitudinal or transverse magnetic field can be placed in the moving end or the static end of the vacuum arc chamber. Although it can be placed directly near the arc contact or slightly away from the arc contact, the magnetic field generated by the former method is smaller than that generated by the latter method. However, a magnetic field can still be generated.

[0076] The new vacuum interrupter thus designed has greater current carrying capacity while ensuring breaking capacity.

[0077] Application example: The patent designs a new structure of vacuum interrupter, which has greater current carrying capacity. The structure of the new vacuum interrupter, except that the arc contact of the middle fixed contact is in the shape of a circular arc, other structures that can make the arc contact of the fixed contact protrude from the main contact of the fixed contact are within the scope of the design, such as Figure 4 the structure shown in FIG. 4, which is in the shape of a flat plate in the middle and the edge is tangent to the circular arc and flat plate, and satisfies the principle of uniform distribution of electric field, is a feasible structure design of the arc contact of the fixed contact. Figure 6

[0078] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above examples, and various changes and improvements can be made without departing from the spirit and scope of the present application. These changes and improvements are within the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents.​

Claims

1. A vacuum interrupter structure having a high breaking capacity for a large current, comprising a structure body, characterized in that, The structure body comprises: A static contact assembly comprising a static end arc contact (1) and a static end main contact (2), the static end arc contact (1) being arranged in front of the static end main contact (2) and protruding in the on-off direction by a preset distance d; A dynamic contact assembly comprising a dynamic end main contact (3) and a dynamic end arc contact (4), the dynamic end main contact (3) and the dynamic end arc contact (4) being in the same plane, the static end arc contact (1) being used to first contact the dynamic end arc contact when the vacuum interrupter with large rated current and strong breaking capacity is closed and to last break when the vacuum interrupter with large rated current and strong breaking capacity is broken, so as to realize arcing only between the static end arc contact (1) and the dynamic end arc contact (4); A vacuum insulation shell, one end of which is in airtight connection with the static contact assembly and the other end of which is connected with the dynamic contact assembly through a bellows, forming a closed vacuum cavity; A bellows (6) for ensuring that the dynamic contact assembly maintains the vacuum degree of the cavity when reciprocating and a bellows shield (5) for adjusting the electric field distribution in the vacuum interrupter; The static end main contact (2) and the dynamic end main contact (3) constitute a main current path for current transmission in a normal current passing state. The static end arc contact (1) and the dynamic end arc contact (4) constitute an arcing path for generating and extinguishing an arc during breaking. The static end arc contact (1) is made of copper-chromium alloy material, and the dynamic end main contact (3) is made of red copper material and plated with silver on the contact surface to enhance the conductivity and corrosion resistance.

2. The vacuum interrupter according to claim 1, wherein The static contact assembly comprises a hollow copper conducting rod (7), the inside of the copper conducting rod (7) is provided with a compression spring (8), and wear-resistant guide sleeves are installed at both ends of the copper conducting rod (7), which cooperate with the copper conducting rod (7) to limit the linear motion of the copper conducting rod (7) in the on-off direction.

3. The vacuum interrupter according to claim 1, wherein The static end arc contact (1) is fixedly connected with the hollow copper conducting rod (7) through a connecting piece, the connecting piece comprises a connecting nut and an extended contact piece with a threaded hole, and the connecting structure enables the static end arc contact (1) to produce a pre-displacement relative to the static end main contact (2) under the action of the compression spring (8).

4. The vacuum interrupter according to claim 1, wherein The dynamic end arc contact (4) is connected with an arc extinguishing coil through riveting or welding, the arc extinguishing coil is a longitudinal magnetic or transverse magnetic structure, and is used to enhance the arcing magnetic field when energized to improve the arc extinguishing capacity.

5. The vacuum interrupter according to claim 1, wherein The dynamic contact assembly further comprises a dynamic conducting rod (9) and a dynamic conducting rod guide sleeve (10), the dynamic conducting rod (9) is electrically connected with the dynamic end main contact (3), and the conducting rod guide sleeve (10) is used to ensure the stability of the dynamic conducting rod (9) during the on-off process.

6. The vacuum interrupter according to claim 1, wherein The bellows shield (5) is made of red copper material and has a shape and length for uniformly distributing the electric field inside the vacuum interrupter.

7. The vacuum interrupter according to claim 1, wherein During the closing process, the dynamic end arc contact (4) first contacts the static end arc contact (1) to form an arcing channel QF2, and then the dynamic end main contact (3) and the static end main contact (2) are closed to form a main current path QF1. In the breaking process, the moving main contact (3) and the static main contact (2) are first disconnected, the moving arc contact (4) and the static arc contact (1) continue to maintain the arc, and finally disconnected, the main contact does not produce arc during the whole process.

8. The vacuum interrupter according to claim 1, wherein The closing time difference between the arc contacts is adjusted by the distance d and the static spring pre-pressing to realize the sequential control of the on-off operation.

9. The vacuum interrupter according to claim 1, wherein The structure of the static arc contact (1) is in the shape of a circular arc, a middle flat plate or a tangent structure of an edge circular arc and a flat plate, which satisfies the design principle of uniform electric field distribution between the contacts during on-off.

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