JP6057887B2 - Vacuum circuit breaker - Google Patents

Description

  The present invention relates to a vacuum circuit breaker having two pairs of contact pairs that open and close in a vacuum space, and particularly to a vacuum circuit breaker having a high rated voltage and requiring high withstand voltage performance and breaking performance.

  In the vacuum valve used in the conventional vacuum circuit breaker, the basic structure is to secure both the breaking performance and the withstand voltage performance using a pair of movable electrode and fixed electrode contacts. In order to cope with the increase in capacity, the number of contacts inside the vacuum valve is increased to two pairs in series, the breaking performance is shared by parallel magnetic field type electrodes with a short gap, and the withstand voltage performance is shared by a withstand voltage electrode with a long gap. There is something that was solved by doing. (For example, see Patent Document 1)

JP 58-68818 A

  In the vacuum valve (Patent Document 1) used in the conventional vacuum circuit breaker, as shown in FIG. 13, the force of the compression spring 36 is applied to the movable side, and the intermediate holder 29 is movable while the withstand voltage electrodes 30 and 31 are pressed against each other. It moves to the right (upward in FIG. 13) together with the holder 32 to open the parallel magnetic field electrodes 27 and 28 (see the lower left column on page 2 of Patent Document 1). Further, the opening distance of the parallel magnetic field type electrodes 27 and 28 is shortened to 10 or less mm, the opening distance of the withstand voltage electrodes 30 and 31 is increased to 10 or more mm, and the arc being interrupted is a parallel magnetic field type. Stroke operation characteristics are given so as to extinguish arcs while the electrodes 27 and 28 are opened (see the lower left column on page 2 of Patent Document 1).

However, when the rated voltage increases, the crest value and initial rise rate of the regenerated voltage at the time of interruption increase, so that the parallel magnetic field type electrodes 27 and 28 open first and the withstand voltage electrodes 30 and 31 open later. In such a vacuum valve, it is necessary to increase the opening speed of the parallel magnetic field type electrodes 27 and 28 to alleviate the high electric field generated between the parallel magnetic field type electrodes accompanying the rise of the regenerative voltage that rises rapidly immediately after the opening.
Furthermore, in order to extinguish the arc being interrupted during the opening of the parallel magnetic field type electrodes 27, 28, the opening distance of the parallel magnetic field type electrodes 27, 28 is increased to increase the wave with a high regenerative voltage. Need to deal with high prices.
If the rated voltage is high, the voltage of the AC withstanding voltage test and the impulse withstanding voltage test also becomes high, so it is necessary to increase the opening speed of the withstanding voltage electrodes 30 and 31.

  As described above, the conventional vacuum valve has a structure in which the intermediate holder 29 moves together with the movable holder 32 while keeping the withstand voltage electrodes 30 and 31 in pressure contact, so that the parallel magnetic field type electrodes 27 and 28 are opened as described above. To increase the pole speed and further increase the opening distance, it is necessary to increase the spring constant of the compression spring 36 and increase the expansion / contraction distance. Therefore, the compression spring 36 is increased in size, and the entire vacuum valve is further increased in size. There was a problem that led to.

The present invention has been made to solve the above-described problems, and does not divide two sets of series-connected electrodes into a breaking electrode and a withstand voltage electrode, and is on the side closer to the switching mechanism. This is caused by the electrode surface welding and subsequent opening due to the large inrush current at the time of turning on, by ensuring both the breaking performance and withstand voltage performance at the electrode and further suppressing the inrush current at the time of turning on. An object of the present invention is to obtain a vacuum circuit breaker having a high breaking performance and a high withstand voltage performance by suppressing damage to the electrode surface.

A vacuum circuit breaker according to the present invention is a vacuum having a contact pair disposed so as to be able to contact and separate in an axial direction of an insulating cylinder and a stud connected to the contact pair in an insulating cylinder held in a sealed state. In a vacuum circuit breaker provided with two valves connected in series, both contact pairs of the first vacuum valve A are movable and the contact pair of the second vacuum valve B is farther from the first vacuum valve A. , The contact closer to the first vacuum valve A is movable, and of the two studs of the first vacuum valve A, the stud A1 located on the second vacuum valve B side is the second vacuum. The movable contact of the valve B is connected to the attached stud B2 so as to move integrally, and the stud A2 away from the second vacuum valve B is connected to an opening / closing mechanism, and the movable contact of the second vacuum valve B is connected. Stud B2 to which is attached The opening spring stud A1 of the first vacuum valve A, which is connected to the head B2 is provided, the resistor is provided in parallel with the contact pair of the second vacuum valve B, the gap of the contact pairs of the first vacuum valve A Is opened before the gap between the contact pairs of the second vacuum valve B.

  According to the present invention, in the vacuum circuit breaker in which two vacuum valves are connected in series, the capacitance formed when the contact pair of the second vacuum valve is opened and the resistor are in parallel. The electric charge flows through the resistor, and the shared voltage of the second vacuum valve becomes small, and almost all of the applied voltage is applied to the contact pair of the first vacuum valve. Therefore, since the first vacuum valve contact pair has a structure that ensures both the breaking performance and the withstand voltage performance, the open spring is strengthened like the conventional vacuum valve, and the first vacuum valve contact pair is It is not necessary to open the contact pair of the second vacuum valve while it is closed, and the open spring can be miniaturized.

  Furthermore, since the contact pair of the first vacuum valve is closed first when it is turned on, a current flows through a resistor provided in parallel with the contact pair of the second vacuum valve, and the inrush current is suppressed. Thereafter, the contact pair of the second vacuum valve is closed with a delay, but the inrush current is closed in a attenuated state. For this reason, there is an effect of suppressing the electrode surface welding that occurs when the inrush current at the time of charging is large and the electrode surface damage caused by the subsequent opening, and the contact pair of the first vacuum valve is also the second vacuum valve. The surface of the contact pair is also kept clean, and the breaking performance and withstand voltage performance can be improved.

It is the sectional side view and circuit block diagram which show the vacuum valve of the vacuum circuit breaker concerning Embodiment 1 of this invention. It is an enlarged view of the connection part of two vacuum valves of the vacuum circuit breaker concerning Embodiment 1 of this invention. It is a sectional side view which shows the vacuum circuit breaker concerning Embodiment 1 of this invention. It is a figure which shows the injection | throwing-in operation | movement of the vacuum valve of the vacuum circuit breaker concerning Embodiment 1 of this invention. It is a figure which shows the opening characteristic of the vacuum valve of the vacuum circuit breaker concerning Embodiment 1 of this invention. It is a figure which shows the opening operation of the vacuum valve of the vacuum circuit breaker which concerns on Embodiment 1 of this invention. It is a figure which compares the inrush current when a small current test is performed with the vacuum circuit breaker according to Embodiment 1 of the present invention and the inrush current in the case of a normal vacuum circuit breaker. It is an enlarged view of the connection part of the two vacuum valves of the vacuum circuit breaker concerning Embodiment 2 of this invention. It is an enlarged view of the connection part of two vacuum valves of the vacuum circuit breaker concerning Embodiment 3 of this invention. It is a figure which shows the injection | throwing-in operation | movement of the vacuum valve of the vacuum circuit breaker concerning Embodiment 3 of this invention. It is a figure which shows the opening operation of the vacuum valve of the vacuum circuit breaker concerning Embodiment 3 of this invention. It is sectional drawing which shows the elastic body holder used for the connection part of two vacuum valves of the vacuum circuit breaker concerning Embodiment 4 of this invention. It is sectional drawing which shows the structure of the vacuum valve in the conventional vacuum circuit breaker.

Embodiment 1 FIG.
Hereinafter, the vacuum circuit breaker of Embodiment 1 of this invention is demonstrated based on FIGS. FIG. 1 shows a vacuum valve used in the vacuum circuit breaker of the present invention. FIG. 1 (a) is a side sectional view showing the vacuum valve, and FIG. 1 (b) is a circuit configuration diagram thereof. FIG. 2 is an enlarged view of a connecting portion of two vacuum valves, and FIG. 3 is a side sectional view showing a vacuum circuit breaker.

1 and 2, a first vacuum valve (referred to as a vacuum valve A) 50 and a second vacuum valve (referred to as a vacuum valve B) 80 are connected in series, and a plate electrode of the second vacuum valve 80 A resistor 40 is connected in parallel with the resistor 86. The vacuum valves 50 and 80 and the resistor 40 are held in a sealed state in a metal cylinder as will be described later.
The first vacuum valve 50 includes ceramics 51 and 52, a metal cylindrical portion 53, an end plate 54, flanges 55 and 56 provided at both ends of the ceramic 51, and flanges 57 and 58 provided at both ends of the ceramic 52. A pair of longitudinal magnetic field electrodes 59, two studs 60 (referred to as studs A1) and studs 61 (referred to as studs A2) to which the longitudinal magnetic field electrodes 59 are fixed are arranged in the vacuum vessel.

The stud (A1) 60 is connected to the end plate 54 via the bellows fixing plate 62 and the bellows 63, and the stud (A2) 61 is connected to the flange 58 via the bellows fixing plate 64 and the bellows 65. With the above configuration, the inside of the first vacuum valve 50 is sealed, and the inside is in a vacuum state.
The feature of the first vacuum valve 50 is that both the stud (A1) 60 and the stud (A2) 61 are connected to the end plate 54 and the flange 58 via bellows 63 and 65, so that they can be moved in the axial direction of the vacuum vessel. It is a point that can be.

  The bellows 65 is a so-called external pressure bellows in which the inside is vacuum and the outside is an insulating gas. This is to prevent buckling because the movable distance of the stud (A2) 61 is large and the opening speed is large as will be described later. A cover 66 is provided around the bellows 65 so that the bellows 65 is not deformed or damaged by touching the bellows 65 during operation.

  The stud (A1) 60 is provided with a guide 67, and the guide 67 defines the movement of the stud (A1) 60 in the axial direction. The stud (A2) 61 is provided with a guide 68, and the guide 68 regulates the movement of the stud (A2) 61 in the axial direction. The guides 67 and 68 are made of plastic or the like to make the copper studs 60 and 61 slip easily. Further, grease may be applied to improve sliding. Since the stud (A2) 61 is driven at a high speed and a large force is applied to the guide 68, it is preferable to reinforce the strength by covering the periphery of the guide 68 with a metal guide cover 69 such as SUS.

Here, the longitudinal magnetic field electrode 59 is composed of a pair of contacts (contact pair) 59a and a coil 59b, and a reinforcing material 59c is provided on the back of the contact 59a so that the coil 59b is not deformed by an opening / closing impact. When the vertical magnetic field electrodes 59 of the short-circuit breaking, by the current flowing through the coil 59b generates an axial magnetic field (vertical magnetic field), for maintaining the arc generated in the gap G _A between the contacts 59a to the diffusion state, The contact surface temperature is suppressed, the generation of metal vapor is suppressed, and high breaking performance is achieved. Further, the contact 59a has a flat plate shape and has a structure in which a high electric field portion is not generated on the surface because the end portion is subjected to R processing.
The metal vapor generated from the contact surface when a short circuit is interrupted by the longitudinal magnetic field electrode 59 is captured by the arc shield 70 to suppress the adhesion of the metal vapor to the creeping surface in the ceramic.

In order to braze the ceramic 51 and the flanges 55 and 56, the ceramic 51 is provided with a metallized layer which is a thin metal. Similarly, the ceramic 52 is provided with a metallized layer which is a thin metal and brazed to the flanges 57 and 58. For this reason, since the end portion of the metallized layer has a high electric field, the electric field relaxation shields 71, 72, 73 are provided outside the vacuum vessel.
As will be described later, an opening / closing mechanism for opening and closing the electrode is connected to the end of the first vacuum valve 50 on the guide 68 side of the stud (A2) 61.

  On the other hand, in the second vacuum valve 80, a ceramic container 81, end plates 82 and 83, and flanges 84 and 85 constitute a vacuum container, and a flat plate electrode 86 having a pair of contacts (contact pairs) 86a is one in the vacuum container. A pair and two studs 87 (referred to as stud B1) and studs 88 (referred to as stud B2) to which the plate electrode 86 is fixed are arranged. The stud (B1) 87 is fixed to the end plate 82, and therefore the contact 86a attached thereto is a fixed contact. On the other hand, the stud (B 2) 88 is connected to the end plate 83 via a bellows fixing plate 89 and a bellows 90. Therefore, only the stud (B2) 88 of the second vacuum valve 80 moves in the axial direction of the vacuum vessel.

  Of the two studs 60, 61 of the first vacuum valve 50, the stud (A1) 60 on the second vacuum valve 80 side has a movable-side contact 86a of the plate electrode 86 of the second vacuum valve 80 fixed thereto. It is connected to the stud (B2) 88 by brazing or the like so as to move integrally. Further, the first vacuum valve 50 and the second vacuum valve 80 are independent from each other as a vacuum vessel, but are connected integrally by brazing or the like at the respective end plates 54 and 83.

An opening spring 74 is provided inside the bellows 63 of the first vacuum valve 50 to generate a force that pushes the stud (A1) 60 downward in the drawing inside the vacuum vessel via the bellows fixing plate 62. This spring force, studs (A1) 60 stud (B2) 88 of the second vacuum valve 80 which integrates the drive and open a gap _{G B} between the contacts 86a of the plate electrode 86. For studs (A1) 60 and the stud (B2) as 88 movement stops at the gap _{G B} is opened to a prescribed length, the stopper 91 provided on the stud (B2) 88, the stopper 91 hits the guide 67 Therefore, the movement of the stud (A1) 60 and the stud (B2) 88 is stopped.

Since the ceramic 81 is provided with a metallized layer which is a thin metal like the first vacuum valve 50 and brazed to the flanges 84 and 85, the end of the metallized layer becomes a high electric field. Therefore, the electric field relaxation shield 92 is provided outside the vacuum vessel, and the electric field relaxation shield 93 is also provided inside the vacuum vessel.
In FIG. 2, which is an enlarged view of the connection portion of the vacuum valve, a vent hole 75 (arrow) is provided in the end plate 54 of the first vacuum valve 50 to insulate the space 76 inside the bellows 63 with the same pressure as the outside of the vacuum valve. The gas is filled. Similarly, the end plate 83 of the second vacuum valve 80 is provided with a vent hole 94 (arrow) so that the space 95 inside the bellows 90 is filled with the insulating gas at the same pressure as the outside of the vacuum valve.

FIG. 3 shows the structure of the vacuum circuit breaker according to the present invention. The first vacuum valve (vacuum valve A) 50 and the second vacuum valve (vacuum valve B) 80 are placed in a tank 1 which is a metal cylinder. Held in a sealed state. An insulating gas is sealed in the tank 1, and the withstand voltage performance is increased by increasing the gas pressure if necessary. As the insulating gas, SF6 gas, dry air, or the like is used.
The tank 1 is at ground potential, and voltage and current are introduced into the vacuum valves 50 and 80 inside the tank by the bushing 2. A shunt 3 is connected to the tip of the central conductor of the bushing 2, and voltage and current are applied to the vacuum valves 50 and 80 via the shunt 3.
In the first embodiment, the first vacuum valve (vacuum valve A) 50 and the second vacuum valve (vacuum valve B) 80 are held in the tank 1 which is a metal cylinder. Even if it is held in a container formed of an insulating material and the insulating gas is sealed, the same effect can be obtained. In addition, the vacuum valve of the first embodiment has the same performance whether installed in the horizontal direction (parallel to the ground) or in the vertical direction.

The first vacuum valve (vacuum valve A) 50 is fixed to the tank 1 via the support 4 and the insulating support member 5. The stud (A2) 61 of the first vacuum valve 50 has an opening / closing mechanism connecting portion 61a, to which the shunt 3 is electrically connected, connected to the connecting conductor 6, via the connecting conductor 6, the insulating rod 7, and the connecting conductor 8. Connected to the opening / closing mechanism 9. A flexible conductor 100 is provided to seal between the connection conductor 8 and the tank 1. Therefore, the flexible conductor 100 uses, for example, a bellows.
The second vacuum valve (vacuum valve B) 80 is fixed to the fixed support 11 by a fixing member 10 to which the shunt 3 is electrically connected. The fixed side support 11 is fixed to the tank 1 via an insulating support member 12.

FIG. 4 shows the closing operation of the vacuum circuit breaker according to the first embodiment, and (1) shows the opening state. When closing the open state mechanism 9 drives the stud (A2) 61 rightwards in the figure, (2) as first gap G _A vertical magnetic field electrode 59 of the first vacuum valve 50 is closed. Further, when driving the stud (A2) 61 rightward in the figure by the opening and closing mechanism 9, shortens press opening spring 74, (3) the way the gap G _B of the plate electrode 86 of the second vacuum valve 80 is closed. Thus, the vacuum circuit breaker is closed.

The opening / closing mechanism 9 is constituted by an electromagnetic drive mechanism or a spring drive mechanism, and is driven so that the moving distance of the stud (A2) 61 is substantially proportional to time. Stud (A1) was determined from the relationship between the 60 and the stud (B2) 88 travel distance and time when driven by the opening spring 74, shown in FIG. 5 the time variation of the opening distance of the gap G _A and the gap G _B .

By adjusting the spring constant of the opening spring 74, the stud (A1) 60 and the stud (B2) for 88 to move slowly, as in FIG. 5 (a), the time is up to about 3ms to open a gap _{G B} The polar distance is almost 0 mm, but after 10 ms and 20 ms have elapsed, it opens to 6 mm and 21 mm. Since the time the movement distance of the stud (A1) 60 increases along with, as shown in FIG. 5 (b), opening the distance of the gap G _A comes slightly attenuated than proportional relation between about 10ms later time. However, in the range of about 10ms after especially important opening for blocking performance ensured, since the opening speed of the gap G _A is sufficiently large, can achieve high breaking performance.

FIG. 6 shows the opening operation of the vacuum circuit breaker of Embodiment 1, and (1) shows the closing state. When opening and closing mechanism 9 from closed state to drive the stud (A2) 61 to the left in the figure, but (2) the gap G _B of the plate electrode 86 of the second vacuum valve 80 to 3ms as hardly open , the gap G _a vertical magnetic field electrode 59 of the first vacuum valve 50 is beginning to open. In addition, as shown in (3), the stud (A1) 60 moves slightly to the left in 10 ms, but the stud (A2) 61 opens at high speed, so that the longitudinal magnetic field electrode of the first vacuum valve 50 gap _{G a} of 59 is wide open.

In a vacuum circuit breaker with a high rated voltage, it is important to ensure advance and small current performance, which will be described below.
A vacuum circuit breaker used for opening / closing a power transmission line or a capacitor bank is required to have a capability of interrupting a small electric current determined by the ground capacitance of the 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 “advanced small current interruption test” together with the advanced small current test for circuit breakers connected to power transmission lines and capacitor banks. This is referred to as the advanced small current interruption test.

In order to investigate the phenomenon inside the vacuum valve, especially the contact surface phenomenon, in the advanced small current interruption test, the result of conducting the contact surface analysis before and after the test by forming a vacuum valve with a glass tube and observing the inside phenomenon with a high-speed camera I found out the following.
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. Thereafter, when the electrode is opened, the above-mentioned welded portion is pulled off, and minute protrusions (welding marks) are generated on the contact surface. If the recurrent voltage of the small current test is applied to the electrode immediately after the opening, a local high electric field is generated in the above-mentioned welding mark, and the withstand voltage performance is lowered, causing re-ignition.

In a vacuum valve (Patent Document 1) used in a conventional vacuum circuit breaker, a parallel magnetic field type electrode for breaking and a withstand voltage electrode with a large opening distance for withstand voltage are provided in series. After closing 30 and the withstand voltage movable electrode 31, the parallel magnetic field type fixed electrode 27 and the parallel magnetic field type intermediate electrode 28 are closed.
For this reason, when the parallel magnetic field type fixed electrode 27 and the parallel magnetic field type intermediate electrode 28 are closed, a pre-arc is generated between the parallel magnetic field type electrodes as described above, an inrush current flows, and welding occurs on the contact surface. Thereafter, when the electrodes are opened, protrusions (welding marks) due to welding removal are generated on the contact surface. Since the parallel magnetic field type electrode opens first at the time of opening, the recurrent voltage of the small current test is applied to the parallel magnetic field type electrode immediately after opening, and a local high electric field is generated at the above-mentioned welding mark. The performance will decrease and cause re-ignition.

In the vacuum valve according to the embodiment of the present invention, it will be described that the occurrence of the above-described welding marks is suppressed by the effect of installing the resistor 40.
FIG. 7 is a diagram comparing the calculated value of the inrush current when an experiment was conducted by incorporating the vacuum circuit breaker of the present invention into the advanced small current breaker test circuit, compared with the case of the conventional vacuum circuit breaker. As shown in FIG. 7A, in the case of a normal vacuum circuit breaker, an inrush current having a peak value of 4 kA flows. For this reason, as described above, a melted portion is generated on the contact surface due to the heat of the pre-arc, and then, when the electrode is opened, minute protrusions (welding marks) due to welding removal are generated on the contact surface. Cause re-ignition.

  On the other hand, as shown in FIG. 7B, in the case of the vacuum circuit breaker of the present invention, since the inrush current is attenuated, the contact surface is not melted by the heat of the pre-arc, and the contact surface is in a clean state. Kept. As a result, the withstand voltage performance increases and the small current interruption performance also increases. In this example, the resistor 40 is set to 300Ω.

  Further, according to the present invention, as shown in FIGS. 1 and 2, the stud (A1) 60 of the first vacuum valve 50 and the stud (B2) 88 of the second vacuum valve 80, which are integrally moved, are respectively bellows. The inner diameter of the bellows 63 connected to the stud (A1) 60 of the first vacuum valve 50 is connected to the stud (B2) 88 of the second vacuum valve 80. The inner diameter of the bellows 90 is smaller.

  The stud (A1) 60 and the stud (B2) 88 are integrated, and the external force acting on the stud (A1) 60 and the stud (B2) 88 is a resultant force of the opening spring 74 and the atmospheric pressure acting on the bellows 63 and the bellows 90. When the inner diameter of the bellows 90 is made larger than the inner diameter of the bellows 63, the atmospheric pressure force is a force that pushes the integrated stud (A1) 60 and stud (B2) 88 toward the contact pair 86a. The force F1 of the atmospheric pressure is constant, but the force F2 of the opening spring 74 becomes weaker as the spring in the compressed state is extended. Therefore, the force F2 of the opening spring 74 is smaller than the force F1 of the atmospheric pressure. Then, the resultant force of F1 and F2 acts in the direction of decelerating the integrated stud (A1) 60 and stud (B2) 88.

If the atmospheric pressure force F1 is not present, the integrated stud (A1) 60 and stud (B2) 88 are rapidly stopped when the contact pair 86a is opened. Since there is a pressure F1 of the atmospheric pressure, the integrated stud (A1) 60 and stud (B2) 88 can be stopped in a decelerated state to suppress the opening shock.
For this reason, there is an effect that the opening / closing life is extended. In addition, vacuum insulation has the characteristic that the withstand voltage performance decreases when the fine particles in the vacuum bulb float to the high electric field part due to impact, so the effect of improving the withstand voltage performance by suppressing the opening impact is effective. is there.

In the vacuum valve of the present invention, as shown in FIG. 3, the fixing member 10 electrically connected to the shunt 3 and the opening / closing mechanism connecting portion 61a are input / output terminals. When the voltage between the input and output terminals in a state where the gap G _B is opened both in the gap G _A and the flat plate electrode 86 of the vertical magnetic field electrodes 59 is applied, electric charge is accumulated in the capacitance C to form a gap G _B plate electrodes 86 but since the thus charge flows through immediately resistor R40, shared voltage of the gap the gap G _B is small, almost all the voltage is applied to the gap G _a. For this reason, since the voltage applied to the vacuum valve 80 is small, there is an effect that the creeping length of the ceramic 81 can be reduced and the vacuum valve 80 can be downsized.

Therefore, the process proceeds at the time of turn-on of a small current test, the time to close the gap G _A before closing gap G _B is the system voltage to be applied to (FIG. 4 (2)), be a maximum voltage to be applied to the vacuum valve 80 In order to withstand this, the electric field design inside the vacuum valve 80 is performed.
As described above, the second vacuum valve 80 is an auxiliary vacuum valve, and the advanced small current interruption and the short-circuit current interruption are performed by the first vacuum valve 50. Therefore, especially for securing the small-current interrupting performance proceeds high transient recovery voltage immediately after opening is applied, opening previously gap G _A vertical magnetic field electrode 59 of the vacuum valve 50 as shown in FIG. 6, the vacuum valve 80 and the gap G _B delayed open method of plate electrode 86.

  If the contact pair 59a is opened when the contact distance of the contact pair 59a is still small, the regenerative voltage is rapidly increasing, and the electric field between the contacts is high, the contact pair 86a forms a capacitance C, Since a current flows between the resistor R and the resistor R provided in the circuit and a transient voltage fluctuation occurs, there is a possibility that the circuit breaks down. Therefore, opening the contact pair 86a with a delay as described above has an effect of suppressing the occurrence of a disconnection failure due to a transient voltage fluctuation.

In the vacuum valve of patent document 1, since the compression spring 36 is incorporated in the vacuum vessel, it is exposed to a brazing temperature of about 800 ° C. For this reason, the spring characteristics may change from those before brazing, resulting in variations in the opening characteristics.
Further, in Patent Document 1, “Because the force of the compression spring 36 is applied to the movable side, the intermediate holder 29 moves to the right together with the movable holder 32 while keeping the withstand voltage electrodes 30 and 31 in pressure contact with each other. “Open the electrodes 27 and 28” (lower left column on page 2). However, as described in the problem to be solved by the invention, in the vacuum valve having a high rated voltage, the re-starting voltage at the time of interruption is also high. The parallel magnetic field type electrode needs to withstand a high voltage applied before the withstand voltage electrode is sufficiently opened immediately after the arc is extinguished.

  For this reason, it is necessary to increase the opening distance of the parallel magnetic field type electrodes 27 and 28. Furthermore, a high electric field is generated between the surface of the parallel magnetic field type electrode and the electrode with the rise of the regenerative voltage that rises rapidly during the opening of the electrode. It is necessary to increase the electrode opening speed. Further, when the diameter of the stud is increased to increase the capacity, the weight increases. For these reasons, if the force of the compression spring 36 is not large, the movement as described in Patent Document 1 is not realized, and the spring becomes large.

In the vacuum valve of the present invention, since the open spring 74 is installed in the atmosphere, when the two vacuum valves are connected, the open spring is not exposed to high-temperature treatment by brazing, and the spring characteristics are stably maintained. It has the effect of becoming a highly functional vacuum circuit breaker. Further, since it is not necessary for the stud (A1) 60 to move following the stud (A2) 61 by the release spring 74, the release spring 74 does not require a particularly large driving force and does not need to be enlarged. is there.
The stud (A1) 60 and the stud (B2) 88 are required to operate stably without being affected by disturbances such as opening / closing impacts. Therefore, in the vacuum valve of the present invention, the guide 67 is provided to regulate and stabilize the movement of the stud (A1) 60 and the stud (B2) 88.

  As described above, in the invention of Embodiment 1, in the vacuum circuit breaker in which two vacuum valves are connected in series, when the advanced small current interruption test is turned on and the contact pair 59a is closed first, the contact pair 86a is connected in parallel. Since a current flows through the provided resistor 40, an inrush current is suppressed. Thereafter, the contact pair 86a closes with a delay, but the current is attenuated, so there is an effect of suppressing the electrode surface welding that occurs when the inrush current at the time of application is large and the electrode surface damage caused by the subsequent opening, The surface of both the contact pair 59a and the contact pair 86a is kept clean, and the breaking performance and withstand voltage performance can be improved. By keeping the contact surface clean, there is an effect that the progress and small current interruption performance can be improved.

  Further, since the capacitance C formed when the contact pair 86a is opened and the resistor 40 are in parallel, the charge of the capacitance C flows through the resistor 40, and the shared voltage of the vacuum valve 80 is reduced. For this reason, the vacuum valve (vacuum valve B) 80 side only needs to have an insulation performance that can withstand the system voltage applied when the vacuum valve (vacuum valve A) 50 is closed. Since the container can be made small, the vacuum circuit breaker can be reduced in size. In addition, since two vacuum vessels are connected, brazing is simplified and manufacturing is easy.

Embodiment 2. FIG.
Next, a vacuum circuit breaker according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 8 is an enlarged view of a connection part of two vacuum valves.
As shown in FIG. 8, the second embodiment of the present invention includes a stud (A1) 60 and a second vacuum valve (vacuum valve B) of the first vacuum valve (vacuum valve A) 50 which are integrally moved. 80 studs (B2) 88 both have a hollow structure. A reinforcing rod 77 may be provided in the hollow structure portion.
Such a structure is advantageous in that the studs 60 and 88 are lighter, so that the movement of the stud by the opening spring 74 is stabilized. Further, there is an effect that the opening spring 74 can be reduced in size. In this case, the current-carrying portions of the studs 60 and 88 need to have a thickness of about the skin thickness or more.

Embodiment 3 FIG.
Next, a vacuum circuit breaker according to Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 9 is an enlarged view of a connection part of two vacuum valves.
As shown in FIG. 9, the third embodiment of the present invention includes a stud (A1) 60 and a second vacuum valve (vacuum valve B) of the first vacuum valve (vacuum valve A) 50 which are integrally moved. The connection portion of the 88 with the stud (B2) 88 does not connect the stud (A1) 60 and the stud (B2) 88 together by brazing as in the first embodiment. The connection is made through the body holder 79.

The elastic body holder 79 is fixed to the stud (A1) 60, and the elastic body 78 is held by the elastic body holder 79. On the other hand, a stopper 96 is fixed to the stud (B 2) 88, and the elastic body 78 is sandwiched between the stopper 96 and the elastic body holder 79. The elastic body holder 79 slides in the axial direction on the outer periphery of the stopper 96, and a flange 79a is provided at the tip of the elastic body holder 79 so as to abut against the stopper 96 and stop sliding. The elastic body 78 is made of a material having elasticity such as a coil spring, a spring such as a disc spring, or rubber. Further, since an impact is applied to the elastic body 78 during the opening / closing operation, it is desirable that the elastic body 78 is fixed to the elastic body holder 79 and the stopper 96 for stable operation.
The conduction between the stud (A1) 60 and the stud (B2) 88 is performed by a flexible conductor 97 connected to each stud. The flexible conductor 97 has a sufficient cross-sectional area for energization.

Also in the third embodiment, the stud (A1) 60 of the first vacuum valve 50 and the stud (B2) 88 of the second vacuum valve 80 that are integrally moved are fixed to the vacuum vessel via the bellows. The inner diameter of the bellows 63 connected to the stud (A1) 60 of the first vacuum valve 50 is smaller than the inner diameter of the bellows 90 connected to the stud (B2) 88 of the second vacuum valve 80. Yes. The release spring 74 is provided on the stud (A1) 60 of the first vacuum valve 50. The other configurations are the same as those shown in FIGS. 1 to 3 shown in the first embodiment, and thus description thereof is omitted.

FIG. 10 shows the closing operation of the vacuum circuit breaker according to the third embodiment, and (1) shows the opening state. When closing the open state mechanism 9 drives the stud (A2) 61 rightwards in the figure, (2) as first gap G _A vertical magnetic field electrode 59 of the first vacuum valve 50 is closed. Further, when the stud (A2) 61 is driven rightward in the drawing by the opening / closing mechanism 9, the elastic body 78 is compressed as shown in (3). When the flange 79a of the elastic body holder 79 comes into contact with the right end portion of the stopper 96 due to the compression of the elastic body 78, the elastic body 78 is held in a compressed state. Further, when the stud (A2) 61 is driven in the right direction in the figure (4) of the way the gap _{G B} of the plate electrode 86 of the second vacuum valve 80 is closed. Thus, the vacuum circuit breaker is closed.
As described in the first embodiment, this closing operation suppresses the inrush current of the advanced small current test and maintains the contact surface in a clean state, so that the withstand voltage performance is improved.

FIG. 11 shows the opening operation of the vacuum circuit breaker according to the third embodiment, and (1) shows the closing state. When opening and closing mechanism 9 from closed state to drive the stud (A2) 61 to the left in the figure, although the gap G _B of the plate electrode 86 of the second vacuum valve 80 hardly opens as in (2), the gap G _a vertical magnetic field electrode 59 of the first vacuum valve 50 is beginning to open. At this time, the stud (A1) 60 is driven leftward by the force of the opening spring 74, and the elastic body 78 is compressed, so that force is generated in both the left and right directions in FIG.

Furthermore, a force in the vacuum valve is applied by the pressure of the insulating gas. For example, since 1 atm is 10 N / cm ² , a force of 253 N is generated when the bellows inner diameter φ100 is set. In this embodiment, since the inner diameter of the bellows 90 is larger than the inner diameter of the bellows 63 as shown in FIG. 9, the pressure applied to the stud (B2) 88 is larger than the pressure applied to the stud (A1) 60. .

Above, the opening spring 74, an elastic member 78, by the force of atmospheric pressure, first stud (A1) 60 moves to the left in a state where the gap _{G B} of the plate electrode 86 of the second vacuum valve 80 is closed. When the flange 79a of the elastic body holder 79 comes into contact with the left end portion of the stopper 96, the elastic body 78 does not extend beyond a specified value. In the flange portion 79a is abutted against the 11 to the left end portion of the stopper 96 of the elastic holder 79 (2), while the gap _{G B} plate electrodes 86 is closed, the stud (A1) 60 is compared with (1) moving to the left Te, but the stud (A2) 61 by the opening and closing mechanism 9 for movement at a high speed, the gap G _a vertical magnetic field electrode 59 is open.

Thereafter, the stud (A1) 60 and the stud (B2) 88 by the force of the opening spring 74 is driven to the left, behind the gap _{G A} gap _{G B} of the flat plate electrode 86 is vertical magnetic field electrode 59 as shown in (3) Open. This delay time can be adjusted by the opening spring 74, the elastic body 78, the pressure of the atmospheric pressure, and the specified length of the elastic body holder 79.

  Thus, while the flat plate electrode 86 of the second vacuum valve 80 is closed, the resultant force of the force that the opening spring 74 drives the stud (A1) 60 and the force that the compressed elastic body 78 tries to open is obtained. The stud (A1) 60 is driven, but the elastic body 78 extends beyond a predetermined length to generate a force for opening the stud (B2) 88. Further, the force for opening the stud (B2) 88 by the elastic body 78 is large. The contact pair 86a of the plate electrode 86 is not opened until the force for closing the stud (B2) due to atmospheric pressure is exceeded. For this reason, the contact pair 59a of the longitudinal magnetic field electrode 59 of the first vacuum valve 50 is opened first by the opening / closing mechanism 9, but the contact pair 86a is opened with a delay.

  If the regenerative voltage is applied to the contact pair 59a of the vertical magnetic field electrode 59 and the contact pair 86a of the flat plate electrode 86 is opened when the electric field between the contacts is high, the contact pair 86a forms a capacitance C and is provided in parallel. If a current flows between the resistor R and a transient voltage fluctuation occurs, there is a possibility of a failure of interruption. Therefore, opening the contact pair 86a of the plate electrode 86 with a delay as described above has an effect of suppressing the occurrence of a failure due to a transient voltage fluctuation.

As described above, in the third embodiment, since the elastic body 78 and the elastic body holder 79 are provided at the connection portion between the stud (A1) 60 and the stud (B2) 88, the elastic body 78 extends until it reaches the specified length. only time can be delayed from the opening time of the gap G _a vertical magnetic field electrodes 59 a opening time of the gap G _B of the plate electrode 86. Therefore, as described in the first embodiment, the regenerative voltage immediately after the opening is applied only to the first vacuum valve 50, and the advanced small current interruption and the short-circuit current interruption can be performed by the vacuum valve 50.

Thus, by applying the recovery voltage to the vacuum valve 50 when the electric field is high between the contacts, open gap G _B of the plate electrode 86 of the vacuum valve 80, it enters a cutoff failure by transient voltage fluctuation occurs There is an effect to suppress.
Further, since the elastic body 78 absorbs an impact when the contact pair 59a of the longitudinal magnetic field electrode 59 is closed at the time of turning on, there is an effect of suppressing chattering.

Embodiment 4 FIG.
Next, a vacuum circuit breaker according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 12 is an enlarged view showing another example of the elastic body holder at the connection portion of the two vacuum valves.
In the invention of the fourth embodiment, the stud (A1) 60 of the first vacuum valve (vacuum valve A) 50 and the stud (B2) 88 of the second vacuum valve (vacuum valve B) 88 as in the third embodiment. Are connected via an elastic body 78 and an elastic body holder 79. As shown in FIG. 12, the elastic body holder 79 is connected to the stud (B2) of the second vacuum valve 80 by a bolt 98. ) 88 is attached by tightening. The elastic body holder 79 has a flange 79a at the left end, and this flange 79a functions as a stopper that defines the length when the elastic body 78 is extended.

The elastic body 78 is attached to the stud (A1) 60 of the first vacuum valve 50 by an attachment member 99.
The fourth embodiment is characterized in that the elastic body holder 79 is formed by tightening the bolt 98, so that the manufacture is easy. 12B has a stopper function when the elastic body 78 is extended, but does not have a stopper function when the elastic body 78 is contracted as shown in FIG. The body 78 has a damper function of absorbing the input impact, and has a great effect of suppressing chattering.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

1: Tank (insulating cylinder) 3: Shunt 9: Opening / closing mechanism 40: Resistor
50: first vacuum valve (vacuum valve A), 59: longitudinal magnetic field electrode,
59a: contact pair of longitudinal magnetic field electrodes, 60: stud (stud A1),
61: Stud (Stud A2), 63, 65, 90: Bellows, 74: Opening spring,
78: elastic body, 80: second vacuum valve (vacuum valve B), 86: plate electrode,
86a: Plate electrode contact pair 87: Stud (stud B1),
88: Stud (Stud B2).

Claims (6)

Two vacuum valves having a contact pair disposed so as to be able to contact and separate in the axial direction of the insulating cylinder and a stud connected to the contact pair are connected in series in an insulating cylinder held in a sealed state. In the vacuum circuit breaker provided
Both contact pairs of the first vacuum valve A are movable, and the contact pair of the second vacuum valve B is fixed at a contact point farther from the first vacuum valve A, and closer to the first vacuum valve A. The stud A1 located on the second vacuum valve B side among the two studs of the first vacuum valve A is a stud B2 to which the movable contact of the second vacuum valve B is attached. The stud A2 that is remote from the second vacuum valve B is connected to an open / close mechanism, and the stud B2 to which the movable contact of the second vacuum valve B is attached or this stud An opening spring is provided on the stud A1 of the first vacuum valve A connected to B2, and a resistor is provided in parallel with the contact pair of the second vacuum valve B ;
The vacuum circuit breaker characterized in that the gap between the contact pairs of the first vacuum valve A is opened before the gap between the contact pairs of the second vacuum valve B.   2. The vacuum circuit breaker according to claim 1, wherein the release spring is provided at a connection portion between the first vacuum valve A and the second vacuum valve B, and the periphery of the release spring is filled with an insulating gas. .   The stud A1 of the first vacuum valve A and the stud B2 of the second vacuum valve B, which are moved together, have a hollow structure, according to claim 1 or 2. Vacuum circuit breaker.   An elastic body is sandwiched between the stud A1 of the first vacuum valve A and the stud B2 of the second vacuum valve B, which are integrally moved, and the stud A1 of the first vacuum valve A and the The vacuum circuit breaker according to claim 1 or 2, wherein energization of the second vacuum valve B with the stud B2 is performed by a flexible conductor connected to each stud.   The stud A1 of the first vacuum valve A and the stud B2 of the second vacuum valve B, which are integrally moved, are fixed to the vacuum vessel via bellows, respectively. The inner diameter of the bellows connected to the stud A1 is made smaller than the inner diameter of the bellows connected to the stud B2 of the second vacuum valve B, according to any one of claims 1 to 4. Vacuum circuit breaker.   The inside of the bellows connected to the stud A1 of the first vacuum valve A and the inside of the bellows connected to the stud B2 of the second vacuum valve B are filled with insulating gas at the same pressure as the outside of the vacuum valve. The vacuum circuit breaker according to claim 5, wherein