JP2014067512A - Vacuum circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve breaking performance especially in a small capacitive current breaking test and a capacitor bank opening and closing test by improving withstand voltage performance without increasing the open electrode distance and open electrode speed of a movable electrode.SOLUTION: Respective movable contacts 2 of one side contact pair B and the other side contact pair A are driven by an opening and closing mechanism 23 so that when closing the vacuum circuit breaker, after the movable contact 2 of one side contact pair B is brought into contact with the stationary contact 3 of the other side contact pair B, the movable contact 2 of the other side contact pair A is brought into contact with the stationary contact 3 of the other side contact pair A, and when opening the vacuum circuit breaker, timing of separation of the movable contact 2 of the other side contact pair A from the stationary contact 3 of the other side contact pair A does not precede timing of separation of the movable contacts 2 of one side contact pair B from the stationary contacts 3 of the one side contact pair B.

Description

  The present invention relates to a vacuum circuit breaker having two contact pairs each opened and closed in a vacuum space, and particularly to a vacuum circuit breaker having a high rated voltage and high shutoff performance in an advanced small current break test and a capacitor bank open / close test. Suitable.

  The basic structure of a vacuum valve used in a vacuum shut-off device is to ensure both shut-off and withstand voltage performance using a pair of contacts. However, in order to cope with the recent increase in voltage and capacity, A vacuum valve in which two sets of contacts are provided inside a vacuum vessel has been devised.

  FIG. 13 is a diagram for explaining the structure of Patent Document 1. In FIG. A central substrate 7 made of a nonmagnetic material is provided in a cylindrical enclosure 1 made of an airtight insulating material. Disk-shaped contacts 10 and 11 are fixed to the central substrate 7. The movable contacts 12 and 13 include a conductive base 22, a spiral wound body 23, a conductive plate 24, a ring 25, and a jumper 26. The movable contacts 12 and 13 are connected to the conductive rods 14 and 15.

  Since the dielectric strength of the vacuum gap increases only by the 0.5th power of the gap length, in the case of a high-voltage vacuum valve, the total gap length is greater when the applied voltage is divided by two sets of contacts than when one set of contacts is used. Can be shortened. For this reason, there exists an effect of making a dielectric strength high and reducing material consumption.

  In addition to this, a two-point cut-off vacuum breaker has been developed in which two vacuum valves containing a pair of contacts are provided in series. In these vacuum circuit breakers, two sets of contacts are opened and closed simultaneously, and the applied voltage is divided by the two sets of contacts.

  Apart from the above methods, a device for improving the withstand voltage performance by improving the contact material has been devised. However, since the high pressure resistant material tends to have a low breaking performance, it is difficult to improve both the withstand voltage performance and the breaking performance at the same time.

Japanese Patent Laid-Open No. 58-14504

  The vacuum circuit breaker used for opening and closing the power transmission line or the capacitor bank is required to have a capability of interrupting a small current that is determined by the ground capacitance of the power transmission line or the capacitance of the capacitor bank. For this reason, it is necessary to perform an advanced small current interruption test and a capacitor bank switching test to inspect the interruption performance. The AC circuit breaker standard JEC2300 commonly used in Japan is referred to as the “advanced small current interruption test” together with the advanced small current test for the circuit breaker connected to the transmission line and capacitor bank. This is referred to as the advanced small current interruption test.

  In the advanced small current interruption test, when the electrode is closed with the circuit voltage applied, the electric field between the fixed electrode and the movable electrode increases, and dielectric breakdown occurs before the electrode is closed. The heat of the arc generated at this time (hereinafter referred to as pre-arc) causes melting on the contact surface of the electrode. Thereafter, the electrode is closed, and the melted portion is welded with the temperature lowered by thermal diffusion. Subsequent opening operation causes the welded site to be peeled off, causing damage to the contact surface. For this reason, the withstand voltage performance is lowered, causing re-ignition.

Since the conventional vacuum circuit breaker of FIG. 13 closes and opens two sets of contacts at the same time, damage due to welding pull-out can occur at either contact. Furthermore, in the advanced small current interruption test, since the test is performed many times, for example, 24 times, it is highly possible that both of the two sets of contacts are damaged. In this state, when a re-start voltage is applied, even if the voltage is divided by the two sets of contacts, a local high electric field is generated at the damaged portion of the contacts, so that the withstand voltage decreases and causes re-ignition.

  The present invention has been made in view of the above-mentioned problems, and is movable by maintaining a clean state in one of the two contact pairs so as not to cause damage due to welding removal. The purpose is to improve the withstand voltage performance without increasing the electrode opening distance and speed, and to improve the breaking performance in the advanced small current breaking test and the capacitor bank switching test.

The vacuum circuit breaker according to the present invention is a vacuum circuit breaker having two pairs of contact pairs A and B each opened and closed in a vacuum space. When the vacuum circuit breaker is closed , the movable contact of one of the contact pairs B is The vacuum circuit breaker is further opened so that the movable contact of the other contact pair A contacts the fixed contact of the other contact pair A after contacting the fixed contact of the one contact pair B. At an extreme time, the timing at which the movable contact of the other contact pair A is separated from the fixed contact of the other contact pair A is such that the movable contact of the one contact pair B is the one of the one contact pair B. The movable contacts of each of the one contact pair B and the other contact pair A are driven by an opening / closing mechanism so as not to come before the timing of releasing from the fixed contact.

  The present invention provides a vacuum interrupter having two pairs of contact pairs A and B each opened and closed in a vacuum space, and when the vacuum interrupter is closed, the movable contact of one of the contact pairs B is the one contact pair. In order that the movable contact of the other contact pair A contacts the fixed contact of the other contact pair A after the contact with the fixed contact B, the other contact pair A is opened when the vacuum breaker is opened. When the movable contact of the contact pair A is separated from the fixed contact of the other contact pair A, the movable contact of the one contact pair B is separated from the fixed contact of the one contact pair B. The movable contact of each of the one contact pair B and the other contact pair A is driven by an opening / closing mechanism so that the opening distance and the opening speed of the movable electrode are increased so that the timing is not earlier than Do And without improving withstand voltage performance, blocking performance in a small current interrupting test and capacitor bank closing test proceeds can be improved.

It is side surface sectional drawing which shows the vacuum interrupting device which concerns on Embodiment 1 of this invention. It is the schematic structure figure which shows the structure of the link mechanism of the opening-and-closing mechanism of the vacuum circuit breaker concerning Embodiment 1 of this invention, and explanatory drawing explaining operation | movement of a contact. It is a figure which shows the average electric field and regenerative voltage between contacts in an advance small current interruption test. It is a figure which shows the average electric field between the contacts in the conventional vacuum interrupter. It is a figure which shows the average electric field between the contacts of the vacuum interrupter which concerns on Embodiment 1 of this invention. It is an enlarged view of the vacuum valve which provided the voltage dividing capacitor with the vacuum circuit breaker concerning Embodiment 2 of this invention. It is a figure which shows the average electric field between the contacts of the vacuum interrupter concerning Embodiment 2 of this invention. In the vacuum circuit breaker concerning Embodiment 2 of this invention, it is a figure which shows the average electric field between contacts when opening distance is shortened. It is a figure which shows the average electric field between contacts when a voltage dividing capacitor is provided in the vacuum circuit breaker according to Embodiment 3 of the present invention and contact A opens with a delay of 1 ms. It is a figure which shows the average electric field between contacts when there is no voltage dividing capacitor in the vacuum circuit breaker concerning Embodiment 3 of this invention, and the contact A opens 1 cycle behind. In the vacuum circuit breaker concerning Embodiment 4 and Embodiment 5 of this invention, it is a figure which shows the average electric field between contacts at the time of making the partial pressure of the A side high with a voltage dividing capacitor. It is an enlarged view of the vacuum valve which provided the impact-absorbing structure in the vacuum interrupter concerning Embodiment 6 of this invention. It is sectional drawing which shows the structure of the vacuum valve in the conventional vacuum interrupter.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS.
In FIG. 1, the vacuum shut-off device mainly includes a tank 20, a vacuum valve 1 installed at the center of the tank 20, an opening / closing mechanism 23 provided outside the tank 20 and a bushing (not shown). The bushing center conductor 25, the vacuum valve 1, and the flexible conductor 16 constitute an electric circuit, and the opening / closing mechanism opens and closes two pairs of the fixed contact 3 and the movable contact 2 in the vacuum valve 1 to thereby open and close the current. Cut into pieces.

The vacuum valve 1 includes two pairs of a fixed contact 3 and a movable contact 2 which are disposed in an insulating cylinder 10 held in a sealed state so as to be opposed to and separated from each other in the axial direction of the insulating cylinder 10. The fixed contact 3 and the movable contact 2 of each set are fixed to the corresponding fixed electrode rod 7 and movable electrode rod 6 via the coil 5, respectively. When the short circuit is interrupted, the current flowing through the coil 5 generates an axial magnetic field (longitudinal magnetic field), thereby maintaining the arc generated between the fixed contact 3 and the movable contact 2 in a diffused state. Such an electrode structure is called a longitudinal magnetic field electrode and has a high blocking performance. Furthermore, since each contact 2 and 3 of each set is a flat plate and does not have the structure which raises electric fields, such as a groove | channel and a protrusion part, it has high withstand voltage performance. For long interruption duties with an arc time of 0.5 cycles or more, the amount of metal vapor generated increases because the arc stays on the contact surface for a long time. There is a risk of migration.
Therefore, a predetermined distance is provided between the fixed contact 3 and the support member 15 via the fixed electrode rod 7 so that the arc does not move to the support member 15. The fixed contact 3 is made larger in diameter than the fixed electrode rod 7 so that the arc does not move from the fixed contact 3 to the fixed electrode rod 7.
In the following, of the two pairs of fixed contact 3 and movable contact 2, the left set of fixed contact 3 and movable contact 2 are referred to as “contact pair A”, and the right set of fixed contact 3 and movable contact 2 are illustrated. 2 is referred to as “contact pair B”.

The fixed electrode rod 7 is fixed to the support member 15 and attached to the center in the axial direction and the center in the radial direction of the insulating cylinder 10. The movable electrode rod 6 is attached to the insulating cylinder 10 via the bellows 8 and the flange 9.
An arc shield 11 is provided for each set at a position surrounding the two sets of fixed contact 3 and movable contact 2. The arc shield 11 prevents the metal vapor generated from the contact when the current is interrupted from adhering to the inner surface of the insulating cylinder 10 and prevents the creepage breakdown voltage from decreasing. The two arc shields 11 and 11 are provided separately so that they can have different potentials.

  An electric field relaxation shield 14 is attached to the support member 15. The vacuum valve 1 is firmly fixed to the tank 20 by a vacuum valve support bushing 22 through a support member 15. The movable electrode rod 6 is connected to the link mechanism 24 that transmits the operation of the opening / closing mechanism 23 through the insulating rod 12, the tank side bellows 13, and the rod 31. The tank side bellows 13 is attached to the tank 20. A split terminal 26 is attached to the movable electrode rod 6, and is connected to the central conductor 23 of the bushing 25 </ b> B by the flexible conductor 16.

  The insulating cylinder 10 is made of ceramic, and a thin metallized layer is provided on the ceramic and fixed to the flange 9 and the support member 15 by brazing. Since the end portion of the metallized layer has a high electric field, the electric field relaxation shield 14 is provided to relax the electric field and prevent discharge along the creeping surface of the ceramic insulating cylinder 10. The electric field relaxation shields 14 positioned at both ends of the insulating cylinder 10 are supported by the flange 9.

Although the tank 20 is at ground potential, the central conductor 25 of the bushing 25B and each conductor in the vacuum valve 1 are at a high voltage, so the vacuum valve support bushing 22 is made of an insulating material such as ceramic or mold resin to ensure a withstand voltage. To do. Furthermore, the vacuum valve support bushing 22 needs to have a mechanical strength sufficient to withstand an impact when the fixed contact 3 and the movable contact 2 are opened and closed. Since the open / close impact is also applied to the fixed electrode rod 7 and the support member 15, these components also have mechanical strength.
The tank 27 is filled with SF6 gas, air, nitrogen gas or the like, which is an insulating gas.

Next, the opening / closing mechanism will be described.
FIG. 2A shows the structure of the link mechanism 24 for transmitting the operation of the opening / closing mechanism 23 to the movable electrode rod 6. For the explanation of the operation of the contact pair A, B, only the fixed contact 3 and the movable contact 2 of the contact pair A, B are extracted from FIG.
The shaft 30 driven by the opening / closing mechanism 23 is connected to a linear joint A27, and the joint A27 is connected to a dog-shaped joint B28. The joint A27 and the joint B28 are supported by the rotating shaft 29 and transmit the movement of the shaft 30. The joint B28 is connected to the rod 31, and the movement of the rod 31 drives the movable electrode rod 6. The rod 31 on the right side (contact pair B side) is provided with a slider 32, and the connecting portion 33 at the end of the joint B28 slides within the slider 32 in the opening and closing direction of the contact pair B for a predetermined length to move the rod 31. It can be done.

The arrow in FIG. 2 (1) shows the movement at the time of insertion. In FIG. 2 (1), the white circle ◯ indicates the rotation axis, and the black circle ● indicates the connecting portion.
When the shaft 30 moves in the upward direction in the figure by the opening / closing mechanism 23, this movement is transmitted to the connecting portion 33 by the joint A27 and the joint B28, and the connecting portion 33 moves in the direction of the arrow in the figure. Since the rod 31 on the right contact pair B side starts to move after the connecting portion 33 slides within the slider 32 for the predetermined length, the right contact pair B can close the contact later than the left contact pair A. After the contact is closed, the movable electrode rod 6 is held at the contact closing position by a latch mechanism (not shown), and the contact is kept closed.

At the time of opening, the latch mechanism of the movable electrode rod 6 of the left contact pair A is removed so that the left movable electrode rod 6 can move, and at the same time, the shaft 30 moves downward in the figure (the direction opposite to the arrow in the figure). First, the rod 31 on the contact pair A side is moved by the movement of the joint B28 on the left side (on the contact pair A side), and the left movable electrode rod 6 moves in the direction to open the left contact pair A. By the movement of the right joint B28, the connecting portion 33 at the tip thereof slides in the slider 32, and immediately before the connecting portion 33 reaches the right end of the slider 32, the latch mechanism of the movable electrode rod 6 of the right contact pair B is removed to the right. The movable electrode rod 6 can be moved. When the connecting portion 33 comes to the right end of the slider 32, the rod 31 on the right contact pair B side starts to move, and the right movable electrode rod 6 moves in the direction to open the right contact pair B. As a result of the above operation, the left contact pair A is opened first, and the right contact pair B is opened later.
The speed VA of the left connecting portion 33 corresponding to the contact pair A and the speed VB of the right connecting portion 33 corresponding to the contact pair B are the length a of the corresponding joint B28 (the left side corresponding to the contact pair A). The length between the rotating shaft 29 of the joint B28 and the connecting portion 33), b (the length between the rotating shaft 29 of the right joint B28 corresponding to the contact pair B and the connecting portion 33) are set to different lengths. You can change it.

  As described above, according to the opening / closing mechanism and the link mechanism of FIG. 2, the opening / closing timing and the opening / closing speed of the left contact pair A and the right contact pair B can be variously changed. In the present embodiment, as shown in FIG. 2 (2), the movable electrode rod 6 and the contact pair on the contact pair A side are contacted so that the contact point A on the left side comes into contact with the contact pair B on the right side after contact with the contact pair B on the right side. The movable electrode rod 6 on the B side is operated, and at the time of opening, the contact pair A and the contact pair B are opened at the same time.

Next, the operation and effect of this structure (Embodiment 1) will be described.
The breaking performance and withstand voltage performance of the vacuum breaker configured as described above will be described in comparison with a conventional vacuum breaker.

  In the advanced small current interruption test, as described in [Problems to be Solved by the Invention], the contact surface is melted by the pre-arc at the time of charging, and the welded site is peeled off and damaged by the subsequent opening. As a result of contact surface analysis and discharge analysis with a high-speed camera, the contact surface has peeled off the welded part, resulting in minute protrusions of several tens to several hundreds of μm. As a result, the withstand voltage performance decreases. Furthermore, peeling of the weld site causes fine particles to be generated on the contact surface, and the fine particles are peeled off from the contact by an electrostatic force when a voltage is applied between the contacts, and accelerated by an electric field between the contacts to become a counter contact. When it collides, it causes discharge.

FIG. 3 shows the average electric field between the contacts (FIG. 3 (1)) and the regenerated voltage (FIG. 3 (2)) in the advanced small current interruption test. In the figure, the horizontal axis indicates the elapsed time from the current zero point.
In the advanced small current interruption test, it is stipulated that the test is performed by changing the arc duration (hereinafter referred to as “arc time”), but this figure shows the case where the arc time is 0 ms. When the arc time is 0 ms, the electric field between the contacts is higher than when the arc time is longer than 0 ms, which is a severe test condition, and is considered suitable for explaining the advanced small current interruption performance.

The average electric field between the contacts indicates a value when the contacts are separated at time 0 s and start to open to the specified gap length at 0.02 s. As shown in FIG. 3 (1), the average electric field between the contacts becomes maximum at 0.007 s in the middle of the opening. If there is no damage on the contact surface, even this maximum electric field does not discharge, but if the contact surface damage occurs and the withstand voltage performance decreases, the average electric field between the contacts will rise to this maximum electric field value or the maximum electric field value. Re-ignition occurs before and after. Therefore, in the following, attention is paid to the rise of the electric field between the contacts immediately after opening and the maximum electric field.
As the withstand voltage performance after the damage has occurred, here, by reducing the regenerative voltage, if the average electric field between the contacts falls to the level of “withstand voltage with welding” in FIG. Assume that it does not occur. In this case, the withstand voltage performance is reduced to 70% when the contact surface is not damaged.

Using the above conditions, it is investigated whether or not an average electric field between contacts and discharge are generated when a small current interruption test is performed in the conventional structure of FIG. In the conventional structure, two sets of contacts are closed and opened simultaneously.
Assume that both of the two contact pairs are damaged. For this reason, when the electric field between the contacts becomes larger than the “withstand voltage with welding” in FIG. The circuit shown in FIG. 4 (3) was used to calculate the partial pressure of the two contact pairs. C (A) is a capacitance between the contacts of the contact pair A, C (B) is a capacitance between the contacts of the contact pair B, and C (bushing) is a capacitance of the vacuum valve support bushing 22.
The regenerative voltage is applied to the contact pair A, and the contact pair B and the lower end (tank 20) of the vacuum valve support bushing 22 are grounded. The contact pair A and the contact pair B are simultaneously opened and opened at the same opening speed. This opening speed is denoted as V (m / s), and in the following, the opening speed is indicated as a relative value based on this speed (for example, a 0.8 times opening speed is denoted as 0.8 V (m / s)).
In order to prevent the electrostatic capacitance between the arc shield 11 and the contact from greatly affecting the potential sharing between the contact pair A and the contact pair B, the arc shield 11 includes the contact pair A side and the contact pair B side. It was assumed that the support member 15 and the support member 15 are insulated from each other.

As a result of the calculation, the partial pressure of contact pair A is 70%, and a higher voltage is applied than contact pair B. Therefore, the electric field exceeds the withstand voltage performance near 0.005s immediately after opening as shown in FIG. Will occur. Then, as shown in FIG. 4 (2), the entire voltage is applied to the contact pair B. However, the contact pair B is also damaged and the withstand voltage performance is lowered, so that the contact pair B is also discharged.
The withstand voltage performance refers to an average electric field between contacts where the discharge probability is low and no discharge occurs even if the test is performed a specified number of times, such as an electric field with a discharge probability of 0.1%.
The number of tests in the advanced small current interruption test is defined by the standard, and when an electric field higher than the withstand voltage performance is applied, the probability of re-ignition within the specified number of tests increases.

FIG. 5 shows the case of Embodiment 1 of the present invention. 2 is used to close the movable electrode rods 6 and 6 so that the contacts 2 and 3 of the left contact pair A come into contact with each other after the contacts 2 and 3 of the right contact pair B contact. At the time of opening and opening, the contact pair A and the contact pair B are simultaneously opened and opened at the same speed.
As a result, the contact pair A is damaged, but the contact pair B is not damaged and is in a clean state. For this reason, peeling of the welded portion does not occur on the surface of the contact pair B, and generation of minute protrusions and fine particles is suppressed, so that the withstand voltage performance is improved.

FIG. 5 (3) shows a circuit for simulating the structure of the first embodiment. As shown in FIG. 5A, since the partial pressure on the contact pair A side is 70%, an electric field exceeding the withstand voltage performance is applied in the vicinity of 0.005 s immediately after the opening of the electrode to generate a discharge. However, since the contact pair B is in a clean state, even if the entire voltage is applied to the contact pair B, the withstand voltage performance is not exceeded and no discharge occurs.
The withstand voltage drop of the contact pair A is not limited to 70% and may be lower. In that case, the discharge at the contact pair A occurs earlier, and the entire voltage is applied to the contact pair B, but the average electric field between the contacts of the clean contact pair B does not exceed the withstand voltage performance, and the discharge does not occur. Does not occur.
Contrary to FIG. 5 (3), a high voltage H.P. When V is applied, no discharge occurs because the withstand voltage performance of the contact pair B is high.

FIG. 5 shows the case where the contact pair A and the contact pair B are opened at the same speed. However, by increasing the opening speed of the contact pair A, the electric field between the contacts of the contact pair A exceeds the withstand voltage performance. Can not be. In this case, both the contact pair A and the contact pair B have an effect that the average electric field between the contacts does not exceed the withstand voltage performance and the reliability is increased.
Conversely, when the opening speed of the contact pair A is lowered, the time during which the electric field between the contacts of the contact pair A exceeds the withstand voltage performance is shortened, but the effect is maintained because no discharge occurs in the clean contact pair B. In this case, since the burden on the bellows 8 on the contact pair A side is reduced, the bellows 8 on the contact pair A side can be downsized.

As described above, in the first embodiment, two pairs of contact pairs A and B are provided in series in one insulating cylinder, and the bellows 8 is provided on each movable electrode rod 6. B can be opened and closed separately,
Furthermore, by one opening / closing mechanism 23 and link mechanism 24,
The movable electrode rods 6 and 6 are operated so that the contact pair A comes into contact with the contact pair B after the contact is closed, and the contact electrode pair A and the contact pair B are opened at the same time when the contact is opened. Because 6 and 6 were operated,
Contact pair A is damaged, but contact pair B is not damaged and is clean,
In advanced small current interruption test and capacitor bank switching test,
Even if a discharge occurs in the contact pair A, the clean contact pair B does not generate a discharge, so that there is an effect that the advanced small current interruption performance and the capacitor bank switching performance are high.

  Since two pairs of contact pairs are housed in one vacuum vessel, there is an effect that the labor of assembling into the tank 20 can be saved. In addition, the vacuum valve can be made smaller than the two vacuum valves 1 and 1 in combination, and the entire vacuum shut-off device can be reduced. This brings about the effect of reduction of material, reduction of transportation work, and compact installation location.

  Since the opening / closing operation is performed by the single opening / closing mechanism 23 and the link mechanism 24, the number of parts is reduced, and the reliability of manufacturing and adjustment is increased.

Embodiment 2. FIG.
Hereinafter, the second embodiment will be described with reference to FIGS.
FIG. 6 shows the structure of the vacuum interrupter according to the second embodiment, which is characterized by providing voltage dividing capacitors 34 and 34. The structure of the other vacuum circuit breaker and the timing of opening and closing are the same as those in the first embodiment.
The voltage dividing capacitors 34 and 34 are provided for both of the two contact pairs A and B, one end of which is electrically connected to the fixed electrode rod 7 through the support member 15 and the other end is connected to the flange 9. So as to be electrically connected to the movable electrode rod 6. Although the detailed structure of each of the voltage dividing capacitors 34 and 34 is omitted, both are configured to secure a withstand voltage by fixing a cylindrical ceramic capacitor connected in series in an insulating cylinder. ing.
The capacitance of the voltage dividing capacitors 34, 34 is made sufficiently large, for example, 70 times larger than the capacitance between the contacts 2 and 3 of the corresponding contact pair A, B when the contacts 2 and 3 are opened by the opening distance. It is. The contact pair A and the contact pair B are opened simultaneously to be separated.

As a result of calculation by the circuit of FIG. 7 (3), as shown in FIG. 7 (1), the partial pressures of the contact pair A and the contact pair B are substantially equal (52% partial pressure to the contact pair A). Since a voltage about 1/2 of the applied voltage is applied to, the electric field between the electrodes is suppressed to 1/2. For this reason, it is possible to reduce the opening speed. In this example, as illustrated in FIG. 7 (1), the opening speed of the contact pair A is 0.8 times the opening speed V when the dividing capacitor is not provided, and the opening speed of the contact pair B is set by the dividing capacitor. It can be lowered to 0.55 times the opening speed V in the absence, and FIGS. 7 (1) and (2) show the electric field when opening at these speeds.
If the opening speed is thus reduced, the opening / closing mechanism can be downsized. Furthermore, since the burden on the bellows 8 is also reduced, the vacuum valve can be downsized as the bellows 8 is downsized.

  Since the vacuum valve also requires a breaking performance, the opening speed for that is necessary. However, since the opening speed for the advanced small current breaking performance is larger, the opening speed can be increased by adopting the second embodiment. Can be reduced.

  Further, if the opening speed is the original opening speed V for both the contact pair A and the contact pair B, the opening distance can be shortened. FIG. 8 shows the electric field between the contacts when the opening distance is the original 82.5%. Because the contact pair A is damaged, the withstand voltage performance is reduced to 70% not only after the first wave but also after the second wave. Both the contact pair A (illustrated in FIG. 8 (1)) and the contact pair B (illustrated in FIG. 8 (2)) have an electric field below the withstand voltage performance, and no discharge occurs.

  As described above, in the second embodiment, the voltage dividing capacitors 34 and 34 are provided corresponding to the contact pairs A and B, respectively, so that the partial pressures of the contact pair A and the contact pair B are equalized. The inter-field is suppressed. For this reason, there is an effect of reducing the opening speed and shortening the opening distance.

Embodiment 3 FIG.
The third embodiment will be described below with reference to FIGS.
In the first and second embodiments described above, the two contact pairs A and B are simultaneously opened at the time of opening. However, in the third embodiment, the contact pair A is delayed from the contact pair B at the time of opening. Open the pole.
Consider the following four cases (1) to (4).

(1) When the voltage dividing capacitors 34 and 34 are present (example in FIG. 6) and the contact pair A opens 1 ms later than the contact pair B.
The capacitances of the voltage dividing capacitors 34, 34 are sufficiently larger, for example, 70 times than the capacitance when the corresponding contacts 2, 3 are opened by the opening distance. The opening speed was Vm / s for both contact pair A and contact pair B.
As shown in FIG. 9 (1), the re-emergence voltage is on the way from 0.005s immediately after the opening of the contact pair A. However, since the gap length is short, a high electric field is applied to the contact pair A and the withstand voltage performance is improved. Exceed. For this reason, discharge occurs in the contact pair A, but since the contact pair B is in a clean state, even if all the voltages are applied to the contact pair B, the withstand voltage performance is not exceeded and no discharge occurs.
Here, when the contact material of the contact pair A is made of a material having a high withstand voltage and a strong resistance to welding removal, discharge in a high electric field immediately after opening is suppressed. In this case, the electric field of “when the contact pair A does not discharge” in FIG. 9B is applied to the contact pair B, and the peak value is suppressed. Therefore, the opening distance of the contact pair B can be shortened.
Since the entire voltage is applied only to the contact pair B from when the contact pair B is opened until the contact pair A is opened, the material of the contact pair B needs to be a material that can withstand this. Further, if the contact pair A is made of a high pressure resistant material, the high pressure resistant material tends to have a low breaking performance, so that the contact pair B needs to secure the breaking performance.

(2) In the case where the contact pair A is opened with a delay of 1 ms from the contact pair B in the same manner without the voltage dividing capacitor (example in FIG. 1).
Since the partial pressure of the contact pair A increases to 60 to 70%, the peak electric field increases to 13.3. Even in this case, even if the contact pair A is discharged, the contact pair B maintains a high withstand voltage performance, so that no discharge occurs even when the entire voltage is applied to the contact pair B.

(3) When there is no voltage dividing capacitor (example in FIG. 1), the timing for opening the contact pair A is delayed for a time longer than 1 ms compared to the opening timing of the contact pair B.
Since the contact is opened when the re-emergence voltage becomes high, the electric field between the contacts immediately after the opening becomes large. For this reason, there is a high possibility that discharge will occur even if the contact pair A is made of a high withstand voltage contact material. However, since the contact pair B has a high withstand voltage performance as in the case described above, no discharge will occur.
When the contact pair A is opened at a high regenerative voltage, the time during which a high electric field is applied between the electrodes becomes long, so that damage to the contact due to discharge increases. Therefore, it is desirable to open the electrode in a range where the reactivation voltage is low, about 2 ms from the rise of the reactivation voltage, and about 2 ms before and after the current zero point after one cycle.

(4) When contact pair A is opened one cycle after the current zero point.
As shown in FIG. 10, since the contact pair A is opened just from the reactivation voltage of 0 kV, a high electric field is not generated immediately after the opening, and is kept below the withstand voltage performance as shown in FIG.
When the withstand voltage performance of the contact pair A further decreases due to damage, a discharge occurs in the contact pair A, but the contact pair B does not discharge as in the case described above.
The partial pressure of the contact A is 50 to 70%.
Actually, since there is a width Δt of variation in the time at which the contact is opened due to the operation of the opening / closing mechanism 23, the contact pair A is opened within the range of Δt one cycle after the rise of the reactivation voltage. When an electromagnetic actuator is used, Δt can be reduced.

  Apart from the above case, a method of opening the contact pair A first is also conceivable. When the arc time is several ms or more, the electric field is relaxed because the gap between the contact pair A is open when the re-starting voltage rises. However, when the arc time is 0 ms, the contact pair B is closed and only the contact pair A is present. Time for applying the re-emergence voltage occurs. For this reason, when a discharge occurs at the contact pair A, it immediately fails. Therefore, this timing should not be applied.

As described above, when the contact pair A is opened later than the contact pair B at the time of opening, a high electric field is applied immediately after the contact pair A is opened, and a discharge occurs. However, the contact pair B is clean. Since the withstand voltage is high, the contact pair B does not discharge. As a result, there is an effect that the advance small current becomes high. The opening timing of the contact pair A is preferably in the range of about 2 ms from the rise of the re-start voltage and about 2 ms before and after the current zero point after one cycle. Furthermore, if the voltage dividing capacitors 34 and 34 are provided and a high voltage contact is applied to the contact pair A, the discharge at the contact pair A can be suppressed.

Embodiment 4 FIG.
Hereinafter, the fourth embodiment will be described with reference to FIG.
In the second embodiment and the third embodiment described above, the partial pressures of the two contact pairs A and B are equalized by the voltage dividing capacitors 34 and 34. However, in the fourth embodiment, the voltage dividing capacitor 34 provides the contact pair B. Thus, the function of the contact pair A is divided into that for withstanding pressure and the contact pair B is divided into functions for breaking. High breakdown voltage materials have relatively low breaking performance, and conversely, materials with high breaking performance tend to have low withstand voltage performance. In this fourth embodiment, both the withstand voltage performance and the breaking performance are improved by separating the functions. Let

FIG. 11 shows the electric field between the contacts when the voltage dividing capacitors 34 and 34 are provided and the capacitance of the capacitors 34 and 34 is double on the contact pair B side than on the contact pair A side. The opening is performed simultaneously with the contact pairs A and B. As a result of calculation, the partial pressure of contact pair A was 66%, and the partial pressure of contact pair B was 34%.
Therefore, it is assumed that the contact pair A is made of a material that maintains a high withstand voltage even after the welding is removed, and has a withstand voltage performance 1.1 times that of the contacts of the other embodiments after the welding is removed. On the other hand, the contact pair B is made of a material having a good breaking performance, and the withstand voltage performance is 70% of the original withstand voltage performance.

With this configuration, as shown in FIG. 11, neither the contact pair A nor the contact pair B has a withstand voltage performance and does not discharge.
Since the high pressure resistant material has a low breaking performance, the breaking of the contact pair A fails at the time of breaking, and the breaking is performed by the contact pair B. For this reason, the partial pressure of the contact pair B needs to be a ratio that can withstand the reactivation voltage of interruption.
High-voltage contact materials include, for example, CuW, CuCr with a Cr ratio of 50% or more, and CuCr with a high-voltage material such as W as the third element. There are some which made the ratio of 30% or less.

  As described above, according to the fourth embodiment, by dividing the function of the contact pair A from the withstand voltage and the contact pair B from breaking by reducing the partial pressure of the contact pair B by the voltage dividing capacitor, the advanced small current breaking performance is obtained. And high current interruption performance can be improved.

Embodiment 5 FIG.
In the above-described fourth embodiment, the contact pair A is applied with a high-breakdown-voltage contact material and the contact pair B is applied with a high-breaking-performance contact material. This is an example of functional separation of the electrode structure and the contact pair B as an electrode structure with a high breaking performance, and there are the following combinations.

(1) The contact pair A is a longitudinal magnetic field electrode, and the contact pair B is also a longitudinal magnetic field electrode.
As an advantage, the longitudinal magnetic field electrode can have a lower opening speed and a shorter opening distance than a spiral electrode described later. Furthermore, since the contacts 2 and 3 of the contact pair A and the contact pair B are flat plates (see FIG. 1 (2)), the withstand voltage performance is also high.
The disadvantage is that the heat generated by energization is large due to the resistance of the coil section 5 (see FIG. 1B). If it is going to suppress resistance of coil part 5, a magnetic field will become weak and interception performance will fall.

(2) The contact pair A is a flat plate electrode, and the contact pair B is a longitudinal magnetic field electrode.
As an advantage, since the resistance of the plate electrode is small, it is possible to increase the current carrying capacity of the contact pair A.
The disadvantage is that since the interruption performance of the flat plate electrode is low, the interruption performance is inferior to the case where both the contact pair A and the contact pair B are longitudinal magnetic field electrodes.

(3) The contact pair A is a flat plate electrode, and the contact pair B is a spiral electrode.
The advantage is that the structure is simple compared to the longitudinal magnetic field electrode, so that the manufacture is easy. Since the resistance is small, the current carrying capacity can be increased.
Disadvantages are interruption by a spiral electrode, and therefore it is necessary to increase the opening speed and increase the opening distance compared to the longitudinal magnetic field electrode.

As described above, in the fifth embodiment, the voltage dividing capacitors 34 and 34 (see FIG. 6) are used to lower the partial pressure of the contact pair B, thereby separating the function of the contact pair A from the withstand voltage and the contact pair B from breaking. As a result, both the advanced small current interruption performance and the large current interruption performance can be enhanced.
Even when the voltage dividing capacitor is not provided, an optimal combination of electrode structures may be selected and optimized in accordance with the responsibility for the interrupting device.

Embodiment 6 FIG.
Hereinafter, the sixth embodiment will be described with reference to FIG.
In the first to fifth embodiments described above, the fixed electrode rod 7 is fixed to the support member 15, and the support member 15 is further fixed to the vacuum valve support bushing 22. Therefore, the contacts 2, 3 are less likely to absorb the impact at the time of closing. The chattering of the contacts 2 and 3 was likely to occur immediately after turning on. Therefore, in the sixth embodiment, a shock absorbing structure 35 at the time of closing is provided.

The shock absorbing structure 35 shown in FIG. 12 is a combination of hollowed hollow discs and fixed to the support member 15 so as to be interposed in the intermediate portion in the axial direction of the fixed electrode rod 7. The impact absorbing structure 35 is distorted by the impact at the time of charging, so that the energy of the impact at the time of charging is absorbed and chattering of the contacts 2 and 3 is prevented. The shock absorbing structure 35 has a small hole 36 so that the central cavity is evacuated. In order to separate the current path and the shock absorbing structure 35, a Cu flexible conductor serving as a current path may be provided separately.
Although a spring may be provided as the shock absorbing structure, the concave structure has an advantage that it is simple and easy to manufacture.

  As described above, since the shock absorbing structure is provided in the support member 15 in the sixth embodiment, chattering of the contacts 2 and 3 immediately after the charging is suppressed. For this reason, damage to the surface of the contacts 2 and 3 due to the arc due to chattering is suppressed, and in particular, there is an effect of maintaining the withstand voltage of the contact pair B to be input first. As a result, the advanced small current interruption performance is enhanced.

The first to sixth embodiments described above have the following characteristics.
Feature 1: A movable contact and a fixed contact disposed in an insulating tube held in a sealed state so as to be able to contact and separate in the axial direction of the insulating tube, and a movable electrode rod fixed to the movable contact are bellows The vacuum valve is attached to the insulating cylinder via a flange and a vacuum circuit breaker having a vacuum valve in which a fixed electrode rod fixed to the fixed contact is attached to the insulating cylinder via a support member. Arranged in series, or two contact pairs A and B are provided in series in one insulating cylinder, each of which has a bellows on each movable electrode bar, and can be opened and closed separately. When the electrode is closed, the movable electrode bar is operated so that the contact A comes into contact with the contact B. When the electrode is opened, the movable electrode bar is set so that the contact B is not separated from the contact A when the electrode is opened. True, characterized by operating It is an air shut-off device.
Due to this feature, welding pull-out occurs only at the contact A, and the contact B is kept clean. Further, when the contact pair A and the contact pair B are simultaneously opened at the time of opening, the applied voltage is divided by the two sets of contacts, so that the electric field of the contact pair A that causes welding pull-out is relaxed.
If the contact pair B is first opened at the time of opening and the contact pair A is opened later, the contact pair A may be discharged due to a high electric field generated by the shared voltage immediately after the opening. Since it is in a clean state, the withstand voltage is high and does not discharge.
As a result, the advanced small current interruption test performance and the capacitor bank switching test performance are improved.
In addition, since the opening / closing operation is performed by a single opening / closing mechanism, the number of parts is reduced, and the reliability of manufacturing and adjustment is increased.

Feature 2: In the above-mentioned feature 1, if the variation in the time for which the contact is opened by the operation of the switching mechanism is Δt, the contact A is opened in the range of Δt one cycle after the rise of the reactivation voltage at the time of opening. It is a vacuum shut-off device characterized by being poled.
Due to this feature, the contact pair A is opened just from the regenerative voltage 0 kV, so that a high electric field immediately after the opening is not generated. For this reason, the discharge at the contact pair A is suppressed, the discharge probability in the small current interruption test is further lowered, and the reliability is increased.

Feature 3: A vacuum circuit breaker characterized in that, in at least one of the above-mentioned features 1 and 2, a voltage dividing capacitor is provided to make the partial pressure of the contact pair A and the contact pair B substantially equal.
Due to this feature, the partial pressures of the contact pair A and the contact pair B are equalized, and the electric field between the electrodes is suppressed to 1/2. For this reason, it is possible to reduce the opening speed and shorten the opening distance.

Feature 4: In at least one of the above-mentioned features 1 and 2, by providing a voltage dividing capacitor and lowering the partial pressure of the contact pair B, the contact pair A is separated from the function for breakdown voltage, and the contact pair B is separated from the function for breaking. The vacuum breaker is characterized in that a high-breakdown-voltage contact material is applied to the contact pair A and a high-breaking-performance contact material is applied to the contact pair B.
With this feature, by applying a high-breakdown-voltage contact material to the contact pair A and a high-breaking-performance contact material to the contact pair B, both the advanced small current breaking performance and the large current breaking performance can be enhanced.

Feature 5: In the features 1 to 4, the electrode structures related to the contact pair A and the contact pair B are both longitudinal magnetic field electrodes, a combination of flat plate electrodes and vertical magnetic field electrodes, or a combination of flat plate electrodes and spiral electrodes. This is a featured vacuum shut-off device.
Due to this feature, the longitudinal magnetic field electrode is excellent in the withstand voltage performance and the interruption performance, but has a disadvantage that heat generation by energization is large due to the resistance of the coil portion. Spiral electrodes and flat plate electrodes are excellent in heat generation when energized, but have a drawback of poor shut-off performance. Therefore, a combination is selected and optimized according to the duty required for the shut-off device.
As in the feature 4, by providing a voltage dividing capacitor and lowering the partial pressure of the contact pair B, when the electrode structure is selected after separating the function of the contact pair A from the withstand voltage and the contact pair B from being cut off, Both the advanced small current interruption performance and the large current interruption performance can be maximized.

Feature 6: A vacuum interrupting device according to the features 1 to 5 described above, wherein a distance is provided between the fixed contact and the support portion so that the arc does not move to the support portion.
Due to this feature, in the interrupting duty with a long arc time of 0.5 cycle or more, the generation amount of metal vapor is large, so that the withstand voltage around the electrode temporarily decreases and there is a risk that the arc moves to other than the electrode. Even in that case, since the arc does not move to the support portion, there is an effect that the interruption performance is high.

Feature 7: A vacuum shut-off device according to the above features 1 to 6, wherein an impact absorbing structure is provided between the fixed electrode rod and the support member.
Due to this feature, a shock absorbing structure is provided on the support member to suppress chattering immediately after being thrown in and prevent damage to the contact surface, thereby maintaining the pressure resistance. As a result, the advanced small current interruption performance is enhanced.

Feature 8: In the above-described features 1 to 7, it is composed of one opening / closing mechanism driven by an electromagnetic actuator or a spring, and a link mechanism that transmits the movement of the opening / closing mechanism to two movable electrodes, and is connected to the movable electrode The vacuum interrupter is characterized in that the moving timing of the two movable electrodes is shifted by providing a slider on the rod.
With this feature, since the two movable electrodes are opened and closed by a single opening / closing mechanism, the number of parts can be reduced and the size can be reduced.

  Feature 9: Two pairs of contacts A and B are provided in series, and each movable electrode rod is provided with a bellows so that it can be opened and closed separately. Operate to close. On the other hand, the contact pair B is prevented from opening after the contact pair A at the time of opening. By this operation, only the contact pair A is welded and pulled off, and the contact pair B is kept clean. The above opening / closing operation is performed by one opening / closing mechanism.

  Characteristic 10: When the contact pair A and the contact pair B are simultaneously opened at the time of opening, the applied voltage is divided by the two sets of contacts, so that the electric field of the contact pair A that causes welding pull-out is relaxed. If the contact pair B is first opened at the time of opening and the contact pair A is opened later, the contact pair A may be discharged due to a high electric field between the contacts due to the shared voltage immediately after opening. Since the contact pair B is in a clean state, the withstand voltage is high and does not discharge. As a result, the advanced small current interruption test performance and the capacitor bank switching test performance are improved. Further, since the opening / closing operation is performed by one opening / closing mechanism, the number of parts is reduced, and the reliability of manufacturing and adjustment is increased.

  Feature 11: Two pairs of contact pairs A and B are provided in series, and each movable electrode rod is provided with a bellows so that it can be opened and closed separately. Is operated to close later. On the other hand, the contact pair B is prevented from opening after the contact pair A at the time of opening. By this operation, only the contact pair A is welded and pulled off, and the contact pair B is kept clean. For this reason, even if a discharge occurs in the contact pair A, the contact pair B is in a clean state, so the withstand voltage is high and does not discharge. As a result, the advanced small current interruption test performance and the capacitor bank switching test performance are improved.

Feature 12: In a vacuum breaker having two contact pairs A and B that open and close in a vacuum space, the movable contact of one of the contact pairs B is fixed to the contact pair B when the vacuum breaker is closed. The timing T _BC when contacting the contact is made before the timing T _AC when the movable contact of the other contact pair A contacts the fixed contact of the contact pair A (that is, T _BC <T _AC ). When the vacuum closing device is opened, the timing T _{AO at} which the movable contact of the other contact pair A is separated from the fixed contact of the contact pair A is the movable contact of the one contact pair B. The one contact pair B and the other contact point are opened so that the contact point does not come before the timing T _{BO when the} contact point B is separated from the fixed contact point (that is, T _BO ≦ T _AO ). That of contact pair A The movable contact is driven by an opening / closing mechanism, and the closing operation causes a pre-arc in the other contact pair A and damages the contact surface, but the one contact pair B is kept clean. Therefore, at the time of opening operation, the one contact pair B that is clean is opened first, or the other contact pair A and the one contact pair B are opened simultaneously, and the electric field of the other contact pair A is opened. Works to lower.

  Feature 13: In a vacuum breaker having two pairs of contact pairs A and B that open and close in the vacuum space, when the vacuum breaker is closed, one contact pair B has its movable contact 2 in contact with its fixed contact 3 After that, the movable contact 2 of the other contact pair A contacts the fixed contact 3 of the contact pair A, and when the vacuum breaker is opened, the fixed contact of the other contact pair A of the movable contact 2 of the other contact pair A Of the one contact pair B and the other contact pair A so that the movable contact 2 of one contact pair B is not separated from the fixed contact 3 of one contact pair B after the separation from the third contact pair B. Each movable contact 2 is driven by an opening / closing mechanism 23, so that the withstand voltage performance is improved without increasing the opening distance or opening speed of the movable electrode. Improved shut-off performance at .

In the present invention, each embodiment can be appropriately modified or omitted within the scope of the invention.
In each of FIGS. 1, 2, 6 and 12, CL1 is movable contact 2, fixed contact 3, coil 5, movable electrode rod 6, fixed electrode rod 7, bellows 8, arc shield 11, insulating rod 12, rod A common center line 31, CL 2, is a common center line for the fixed electrode rod 7, the electric field relaxation shield 14, the support member 15, and the vacuum valve support bushing 22. Moreover, in each figure of FIGS. 1-12, the same code | symbol shows the same or an equivalent part.

1 vacuum valve, 2 movable contact, 3 fixed contact,
4 longitudinal magnetic field electrode, 5 coil, 6 movable electrode rod,
7 fixed electrode rod, 8 bellows, 9 flange,
10 insulation cylinder, 11 arc shield, 12 insulation rod,
13 tank side bellows, 14 electric field relaxation shield, 15 support member,
16 flexible conductors, 17 guides, 18 blocks S,
19 support insulators, 20 tanks, 21 lids,
22 Vacuum valve support bushing, 23 Opening / closing mechanism,
24 link mechanism, 25 bushing center conductor,
25B bushing, 26 split terminal, 27 joint A,
28 joint B, 29 rotating shaft, 30 shaft,
31 rod, 32 slider, 33 connecting part,
34 partial pressure capacitor, 35 shock absorbing structure, 36 holes,
CL1, CL2 center line.

Claims (17)

  In a vacuum breaker having two pairs of contact pairs A and B that open and close in the vacuum space, when the vacuum breaker is closed, the movable contact of one contact pair B is the fixed contact of the one contact pair B In order that the movable contact of the other contact pair A contacts the fixed contact of the other contact pair A after the contact with the other contact pair A, the other contact pair A is further opened when the vacuum interrupter is opened. The timing at which the movable contact of the one contact pair B is separated from the fixed contact of the other contact pair A is before the timing at which the movable contact of the one contact pair B is separated from the fixed contact of the one contact pair B. In order to prevent this, the movable contact of each of the one contact pair B and the other contact pair A is driven by an opening / closing mechanism.   In the vacuum circuit breaker having two pairs of contact pairs A and B that open and close in the vacuum space, when the vacuum circuit breaker is closed, one of the contact pairs B has its movable contact brought into contact with the fixed contact, The movable contact of the other contact pair A contacts the fixed contact of the contact pair A, and the fixed contact of the one contact pair B of the movable contact of the one contact pair B when the vacuum interrupter is opened. The one contact pair B and the other contact pair B and the other contact pair A and the other contact pair A are separated from the fixed contact of the other contact pair A at the same time. A vacuum circuit breaker characterized in that each movable contact of the contact pair A is driven by an opening / closing mechanism.   In the vacuum circuit breaker having two pairs of contact pairs A and B that open and close in the vacuum space, when the vacuum circuit breaker is closed, one of the contact pairs B has its movable contact brought into contact with the fixed contact, The movable contact of the other contact pair A contacts the fixed contact of the contact pair A, and the fixed contact of the one contact pair B of the movable contact of the one contact pair B when the vacuum interrupter is opened. The one contact pair B and the other contact pair are separated from the other contact pair A so that the movable contact of the other contact pair A is separated from the fixed contact of the other contact pair A. A vacuum circuit breaker characterized in that each movable contact of the contact pair A is driven by an opening / closing mechanism.   The vacuum interrupter according to claim 3, further comprising a link mechanism that transmits the movement of the opening / closing mechanism to the movable contacts of the one contact pair B and the other contact pair A, The rod connected to the movable contact through a movable electrode rod is provided with a slider for shifting the moving timing of the movable contacts of the one contact pair B and the other contact pair A. Vacuum shut-off device.   The vacuum interrupter according to any one of claims 1 to 4, wherein the two pairs of contact points A and B are disposed in a common vacuum vessel.   The vacuum interrupter according to any one of claims 1 to 4, wherein the two sets of contact pairs A and B are respectively disposed in individual vacuum vessels.   7. The vacuum circuit breaker according to claim 1, wherein the movable contacts of the two pairs of contact pairs A and B are driven by the common opening / closing mechanism. .   The vacuum interrupter according to any one of claims 1 to 7, wherein Δt is a width of variation in time when the movable contact of the other contact pair A is separated from the fixed contact of the other contact pair A. Then, at the time of opening, the movable contact of the other contact pair A is separated from the fixed contact of the other contact pair A within a range of Δt after one cycle from the rise of the reactivation voltage. A vacuum switchgear. The vacuum circuit breaker according to any one of claims 1 to 8, wherein a voltage dividing capacitor is provided, and a partial pressure of the one contact pair B and the other contact pair A is substantially equal by the voltage dividing capacitor. A vacuum shut-off device characterized by being.   9. The vacuum circuit breaker according to claim 1, wherein a voltage dividing capacitor is provided, and the partial pressure of the one contact pair B is lowered from the divided pressure of the other contact pair A by the voltage dividing capacitor. Accordingly, the other contact pair B is a breaking contact pair, the one contact pair A is a pressure-resistant contact pair, and the other contact pair B is formed of a high breaking performance contact material, A vacuum circuit breaker characterized in that one contact pair A is formed of a high pressure resistant contact material.   The vacuum interrupter according to any one of claims 1 to 10, wherein each of the one contact pair B and the other contact pair A is a flat plate electrode.   The vacuum circuit breaker according to any one of claims 1 to 10, wherein each of the one contact pair B and the other contact pair A is a longitudinal magnetic field electrode.   The vacuum circuit breaker according to any one of claims 1 to 10, wherein the one contact pair B and the other contact pair A are a combination of a plate electrode and a longitudinal magnetic field electrode. .   The vacuum interrupter according to any one of claims 1 to 10, wherein the one contact pair B and the other contact pair A are a combination of a plate electrode and a spiral electrode.   The vacuum interrupter according to any one of claims 1 to 14, wherein the support portion that supports the fixed contact and the fixed contact include a fixed electrode rod so that an arc does not move from the fixed contact to the support portion. A vacuum shut-off device characterized by being spaced apart by a predetermined distance.   16. The vacuum interrupter according to claim 15, wherein an impact absorbing structure that absorbs an impact at the time of closing is provided between the fixed electrode rod and the support portion. .   17. The vacuum circuit breaker according to claim 1, wherein the opening / closing mechanism is an open / close mechanism that is driven by an electromagnetic actuator.

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