Two-section type series vacuum circuit breaker

Abstract

The invention provides a two-section type series vacuum circuit breaker. The vacuum circuit breaker comprises a first vacuum arc-extinguishing tube, a second vacuum arc-extinguishing tube and a third vacuum arc-extinguishing tube, a second vacuum arc extinguishing tube; a telescopic rod; a contact arm which is provided with a contact; a piezoresistor; wherein the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube are connected in series, and telescopic rods are respectively arranged at the end parts of the outer sides of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube and are used for controlling the opening and closing of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube. The corresponding contact of the contact arm is provided with the piezoresistor.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum circuit breakers, and in particular to a two-stage series vacuum circuit breaker. Background Art

[0002] In the current prior art, the existing vacuum circuit breaker structure is generally a single-tube structure. At the moment when the moving and static contacts of the vacuum tube are disconnected, the vacuum circuit breaker with a single-tube structure will have a surge problem. Due to the capacitance between the two contacts, the insulation between the contacts is broken, thereby generating metal vapor and forming a vacuum arc. The density and temperature of the charged particles in the arc column in the vacuum are much higher than those of the surrounding medium, which causes the vacuum arc column to diffuse rapidly to the vacuum area outside the arc column, forming a very strong diffusion current. When the disconnected current approaches zero, the temperature and pressure of the arc between the contacts drop sharply, making the arc unable to continue to be maintained and extinguished quickly and reliably. Within a few microseconds after the arc is extinguished, the vacuum withstand voltage level between the two contacts recovers rapidly, and the recovery speed can reach 20kV / μs. The above-mentioned high-voltage arc has a great influence on the wear of the contacts of the single-tube vacuum tube, and has a certain loss on the overall life of the vacuum tube. Summary of the invention

[0003] One of the inventive purposes of the present invention is to provide a two-stage series vacuum circuit breaker, wherein the vacuum circuit breaker is a two-stage series structure, wherein the two-stage series structure combined with a parallel varistor vacuum circuit breaker can effectively absorb energy from two contacts of the vacuum circuit breaker, so that the instantaneous voltage of the breakpoint between the two contacts can be effectively reduced when a large current is switched, thereby effectively improving the service life of the vacuum circuit breaker.

[0004] Another object of the present invention is to provide a two-stage series vacuum circuit breaker. During the two-stage switching process of the vacuum circuit breaker, there may be a problem that the two contacts are not switched synchronously. If the contacts of the two-stage vacuum circuit breaker are not switched synchronously, an instantaneous voltage higher than the voltage divider voltage will be generated at one of the contacts that contacts first, thereby causing certain damage to the contacts that are switched asynchronously. In fact, since the switching process is a mechanical action, it is inevitable that the contacts will be out of sync. Therefore, the present invention is based on the two-stage series vacuum circuit breaker structure. Further, two contacts are provided with varistors on another parallel path. The nonlinear volt-ampere characteristic curve of the varistor and the two-path parallel structure are used to reduce the damage to the contacts caused by the high instantaneous voltage caused by the asynchronous switching, thereby improving the life of the contacts.

[0005] Another inventive object of the present invention is to provide a two-stage series vacuum circuit breaker, wherein the vacuum circuit breaker is configured with a varistor with a nonlinear volt-ampere characteristic as a varistor in the contact, wherein the varistor is preferably zinc oxide, and when the corresponding asynchronous contacts are first contacted and the instantaneous voltage of the contacts is higher than the threshold voltage of the varistor, the varistor in parallel quickly reduces its resistance. According to the principle of equal voltage in parallel circuits, the asynchronous switching voltage increase of the two-stage series vacuum circuit breaker can be effectively suppressed, and the current energy of the instantaneous contact can be absorbed, thereby effectively protecting the high voltage impact of the asynchronous contact of the contacts of the two-stage series vacuum circuit breaker.

[0006] In order to achieve at least one of the above-mentioned invention objects, the present invention further provides a two-stage series vacuum circuit breaker, the vacuum circuit breaker comprising: The first vacuum arc extinguishing tube; A second vacuum arc extinguishing tube; Telescopic rod; A contact arm having a crossbar conductor thereon; Varistor; The first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube are connected in series, and telescopic rods are respectively provided at the outer ends of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube, and the telescopic rods are used to control the opening and closing of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube. The outer ends of the cross-bar conductors corresponding to the contact arms have the varistors in contact with each other, and one path of the cross-bar conductor and the varistor corresponding to the contact arms and one path of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube in series form a two-path parallel structure, and the varistor is used to control in parallel the switching voltage formed by the series voltage division of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube.

[0007] According to one of the preferred embodiments of the present invention, the electrical connection ends at both ends of the outer sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are respectively provided with corresponding conductive strips, and the conductive strips are connected to the telescopic rods at the corresponding positions, and the conductive strips are contacted and connected with the contacts at the corresponding positions through the movement of the telescopic rods at the corresponding positions.

[0008] According to another preferred embodiment of the present invention, the contact arm includes a first contact arm arranged at the electrical connection end on both sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube connected in series, and a second contact arm respectively arranged in the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube, and the second contact arm includes a moving contact and a static contact, and the moving contact is connected to the corresponding telescopic rod for controlling the separation and connection of the moving contact and the static contact.

[0009] According to another preferred embodiment of the present invention, one end is connected to the moving contact of the second contact arm, and the other end is connected to a reset spring, and the reset spring is used for resetting the moving and static contacts when power is off. The reset springs are provided at both ends of the outer sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube.

[0010] According to another preferred embodiment of the present invention, the first contact arms are respectively arranged to be two for input current and output current, and opposite cross bar conductors are respectively arranged on the two first contact arms, and the outer ends of the two opposite cross bar conductors are respectively arranged with the varistors, wherein the varistors are in contact with each other or formed as one piece, and when the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are switched, the non-simultaneous instantaneous voltage of the switching voltage of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube is controlled through the parallel connection of the conductor cross bar connected by the two first contact arms and the varistors.

[0011] According to another preferred embodiment of the present invention, when the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are switched on, the instantaneous high voltage generated by the asynchronous switching is greater than the inflection point voltage of the volt-ampere characteristic of the varistor, so that the resistance of the varistor decreases rapidly, and the current in the path where the varistor is located increases rapidly, which is used to absorb the instantaneous high voltage energy and reduce the instantaneous high voltage when the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are connected in series to divide the voltage.

[0012] According to another preferred embodiment of the present invention, a varistor corresponding to the voltage-sensitive threshold is configured according to the electrical parameter types of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube, wherein the varistor is a zinc oxide varistor.

[0013] According to another preferred embodiment of the present invention, the vacuum circuit breaker includes an insulating shell, which is arranged on the outside of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube and covers the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Shown is a cross-sectional structural schematic diagram of a two-stage series vacuum circuit breaker in the present invention.

[0015] Figure 2 Shown is a schematic diagram of the parallel varistor structure of one of the preferred embodiments of a two-stage series vacuum circuit breaker in the present invention.

[0016] First contact arm 11, contact 111, conductive strip 112, crossbar conductor 113, second contact arm 21, moving contact 211, stationary contact 212, first vacuum tube 31, second vacuum tube 32, telescopic rod 41, return spring 42, varistor 50, insulating shell 60. DETAILED DESCRIPTION

[0017] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0018] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0019] Please combine Figure 1-Figure 2 The present invention discloses a two-stage series vacuum circuit breaker, the structure of which includes the following parts: a first vacuum arc extinguishing tube; a second vacuum arc extinguishing tube; a telescopic rod; a contact arm, on which a contact is provided; a varistor, wherein the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are connected in series, and the two outer ends of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube after being connected in series are respectively provided with the telescopic rod, wherein the telescopic rod is connected to the contact arm in the corresponding vacuum arc extinguishing tube, and is used to control the separation and combination of the moving and static contacts in the corresponding vacuum arc extinguishing tube. It should be noted that the series structure of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube in the present invention can effectively divide the high voltage contact, thereby reducing the risk of damage to the moving and static contacts. Generally speaking, after the vacuum arc extinguishing tubes of the same specification are divided in series, the contact voltage of each vacuum arc extinguishing tube is half of the original voltage. However, in the actual operation process, the contact of the contacts needs to be synchronized to maintain the ideal voltage division state. However, when the operating mechanism is used to control the separation and combination of the moving and static contacts in the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube in series, it is difficult to achieve synchronization by mechanical control. When it is not synchronized, an instantaneous voltage higher than the divided voltage will appear on the contact. Therefore, based on the structure of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube in series, the present invention further configures the varistor connected in parallel with the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube in series. The parallel varistor is used to limit the increase of the instantaneous voltage and absorb the instantaneous current caused by the high instantaneous voltage.

[0020] Specifically, the present invention respectively sets crossbar conductors on the two contact arms of the input current and the output current, and respectively sets the varistor at the outer ends of the two crossbar conductors, wherein the varistor can be a contact structure or an integrally formed structure. When the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are switched on, the instantaneous high voltage generated by the asynchronous switching is greater than the inflection point voltage of the volt-ampere characteristic of the varistor, so that the resistance of the varistor decreases rapidly, and the current of the one path where the varistor is located increases rapidly, which is used to absorb the instantaneous high voltage energy and reduce the instantaneous high voltage of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube connected in series to divide the voltage.

[0021] As shown in the figure, the first contact arms are respectively arranged to be two for input current and output current, and opposite cross bar conductors are respectively arranged on the two first contact arms, and the outer ends of the two opposite cross bar conductors are respectively arranged with the varistors, wherein the varistors are in contact with each other or formed as one piece, and when the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are switched on and off, the non-simultaneous instantaneous voltage of the switching voltage of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube is controlled through the parallel connection of the conductor cross bar and the varistor connected by the two first contact arms.

[0022] The specific structure of the two-stage series vacuum circuit breaker includes the following parts: the electrical connection ends at both ends of the outer sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are respectively provided with corresponding conductive strips, and the conductive strips are connected to the telescopic rods at the corresponding positions, and the conductive strips are contacted and connected with the contacts at the corresponding positions through the movement of the telescopic rods at the corresponding positions.

[0023] The contact arm includes a first contact arm arranged at the electrical connection ends on both sides of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube connected in series, and a second contact arm respectively arranged in the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube, and the second contact arm includes a moving contact and a static contact, and the moving contact is connected to the corresponding telescopic rod for controlling the separation and connection of the moving contact and the static contact.

[0024] One end is connected to the moving contact of the second contact arm, and the other end is connected to a reset spring. The reset spring is used for resetting the moving and static contacts when power is off. The reset springs are provided at both ends of the outer sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube.

[0025] A varistor corresponding to the voltage-sensitive threshold is configured according to the electrical parameter types of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube, wherein the varistor is a zinc oxide varistor.

[0026] The vacuum circuit breaker comprises an insulating shell, which is arranged outside the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube and covers the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube.

[0027] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments. Without departing from the principles, the implementation methods of the present invention may be deformed or modified in any way.

Claims

1. A two-stage series vacuum circuit breaker, characterized in that: The vacuum circuit breaker comprises: The first vacuum arc extinguishing tube; A second vacuum arc extinguishing tube; Telescopic rod; A contact arm having a crossbar conductor thereon; Varistor; The first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube are connected in series, and telescopic rods are respectively provided at the outer ends of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube, and the telescopic rods are used to control the opening and closing of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube. The outer ends of the cross-bar conductors corresponding to the contact arms have the varistors in contact with each other, and one path of the cross-bar conductor and the varistor corresponding to the contact arms and one path of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube in series form a two-path parallel structure, and the varistor is used to control in parallel the switching voltage formed by the series voltage division of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube.

2. A two-stage series vacuum circuit breaker according to claim 1, characterized in that: The electrical connection ends at both ends of the outer sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are respectively provided with corresponding conductive strips, and the conductive strips are connected to the telescopic rods at the corresponding positions, and the conductive strips are contacted and connected to the contacts at the corresponding positions through the movement of the telescopic rods at the corresponding positions.

3. A two-stage series vacuum circuit breaker according to claim 1, characterized in that: The contact arm includes a first contact arm arranged at the electrical connection end portions on both sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube connected in series, and a second contact arm respectively arranged in the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube, and the second contact arm includes a moving contact and a static contact, and the moving contact is connected to a corresponding telescopic rod for controlling the separation and connection of the moving contact and the static contact.

4. A two-stage series vacuum circuit breaker according to claim 1, characterized in that: One end is connected to the moving contact of the second contact arm, and the other end is connected to a reset spring. The reset spring is used for resetting the moving and static contacts when power is off. The reset springs are provided at both ends of the outer sides of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube.

5. A two-stage series vacuum circuit breaker according to claim 1, characterized in that: The first contact arms are respectively arranged to be two for input current and output current, and opposite cross bar conductors are respectively arranged on the two first contact arms, and the outer ends of the two opposite cross bar conductors are respectively arranged with the varistors, wherein the varistors are in contact with each other or formed as one piece, and when the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are switched on and off, the non-simultaneous instantaneous voltage of the switching voltage of the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube is controlled through the parallel connection of the conductor cross bar connected by the two first contact arms and the varistors.

6. A two-stage series vacuum circuit breaker according to claim 1, characterized in that: When the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are switched on, the instantaneous high voltage generated by the asynchronous switching is greater than the inflection point voltage of the volt-ampere characteristic of the varistor, so that the resistance of the varistor decreases rapidly, and the current in the path where the varistor is located increases rapidly, which is used to absorb the instantaneous high voltage energy and reduce the instantaneous high voltage when the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube are connected in series to divide the voltage.

7. A two-stage series vacuum circuit breaker according to claim 1, characterized in that: A varistor corresponding to the voltage-sensitive threshold is configured according to the electrical parameter types of the first vacuum arc-extinguishing tube and the second vacuum arc-extinguishing tube, wherein the varistor is a zinc oxide varistor.

8. A two-stage series vacuum circuit breaker according to claim 1, characterized in that: The vacuum circuit breaker comprises an insulating shell, which is arranged outside the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube and covers the first vacuum arc extinguishing tube and the second vacuum arc extinguishing tube.

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