JP2013093129A - Gas circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas circuit breaker to which a driving method for accelerating an opening speed in leading small current interruption while driving energy is being reduced.SOLUTION: A gas circuit breaker is constituted such that a first contact section 20 and a second contact section 10 individually provided with a first arcing contact 21 and a second arcing contact 11 on a central axis cl inside a sealed container 80 are disposed opposite to each other and that the first contact section 20 is driven by an operating mechanism section at the time of opening operation and closing operation. The gas circuit breaker is provided with an arm ratio control function which is disposed between the first contact section 20 and the operating mechanism section and is constituted of: a stationary cam plate 40 on which a guide groove 40a having a curved line shape is formed; a rotary lever 50 of which one end is swingably supported by a fulcrum pin 60 at a predetermined position in a direction perpendicular to the guide groove 40a and other end has a slot 50a formed thereon; and a driving rod 51 coupled to the operating mechanism section via a pin 62 at an intermediate portion of the rotary lever 50 by fixing a pin 61 to an end of the first contact section 20, causing the pin 61 to be loosely fitted into both the slot 50a and the guide groove 40a and coupling an end of an insulation rod 27 and the end of the rotary lever 50 to each other.

Description

  Embodiments described herein relate generally to a gas circuit breaker that reduces drive energy for driving a movable contact portion.

  Conventionally, there is a puffer type gas circuit breaker as a large-capacity gas circuit breaker capable of breaking from a small current to a large current. FIG. 4 is a diagram showing a state in which the shut-off operation is completed from the on-state before the shut-off operation of the puffer type gas circuit breaker, FIG. 4a is a cross-sectional view showing the on-state before the shut-off operation, and FIG. FIG. 4C is a cross-sectional view showing a state immediately after the arc contact is opened, FIG. 4C is a cross-sectional view showing a state where the breaking operation has further progressed, and FIG. 4D is a cross-sectional view showing a state where the breaking operation is further completed.

In FIG. 4a, in a sealed container (not shown) filled with an arc extinguishing gas, a stationary contact portion 10 provided on the stationary side and a movable contact portion 20 are arranged opposite to the stationary contact portion 10. ing. In the following description, regarding the positional relationship of the movable contact portion 20, the direction on the fixed contact portion 10 side is defined as “front”, and the opposite side is defined as “rear”. In addition, the arc extinguishing gas is any gas such as SF ₆ , carbon dioxide gas, nitrogen gas, or a mixed gas thereof.

  The movable contact portion 20 has a hollow operation rod 26 connected to a swingable insulating rod 27 via a pin 28, and is arranged around the operation rod 26 and connected to the operation rod 26 at a front end portion. A cylinder 25, an annular (disc-shaped disk having a hole in the center), which will be described later, inserted into the cylinder 25, and a hollow and finger-shaped (finger-shaped) connected in front of the cylinder 25 A movable arc contact 21, an insulation guide 22 provided so as to surround the movable arc contact 21, an insulation nozzle 23 disposed on the outer periphery of the insulation guide 22 with an annular passage, and further this insulation nozzle The movable energizing contact 24 is disposed concentrically outside the cylinder 23 and connected to the front of the cylinder 25.

  On the other hand, the fixed-side contact portion 10 includes a fixed arc contact 11 fixed by a cylindrical support portion 14 that contacts the outer peripheral portion of the movable energizing contact 24 and a support portion 13 fixed to the support portion 14. And a fixed energizing contact 12 fixed to a support portion 14 disposed so as to surround the fixed arc contact 11. Reference numeral 14 a denotes an opening of the support portion 14.

  A space between the fixed arc contact 11 and the movable arc contact 21 is an arc space, a space around the arc contact 11 communicating with the arc space is a downstream space, and a space between the cylinder 25 and the fixed piston 29 is a pressure accumulating space. Respectively.

  Of the movable contact portion 20 configured as described above, the operation rod 26 is configured to reciprocate in the axial direction thereof by the drive device 4 (not shown) via the insulating rod 27. In the middle, it has a plurality of openings 26a communicating the hollow portion with the filling gas atmosphere space.

  Further, the annular space between the insulating guide 22 and the insulating nozzle 23 functions as an upstream gas flow path for introducing the compressed gas formed in the cylinder 25 into the arc space as a gas flow. Yes.

  Further, as described above, the fixed piston 29 is formed in a circular flat plate shape having a hole in the center portion, and slides with respect to the outer peripheral surface of the operation rod 26 on the inner peripheral surface thereof, and the cylinder on the outer peripheral surface thereof. It is comprised so that it may slide with respect to the inner peripheral surface of 25. In this case, the fixed piston 29 is integrally provided at the rear thereof, and a piston support portion 29a extending in the axial direction is fixed in a container (not shown) by the support portion 29b.

  Here, when the gas circuit breaker's breaking operation starts in the state of FIG. 4a, the rear insulating rod 27 moves in the direction of the arrow shown in the figure, so that the movable contact portion 20 including this insulating rod 27 moves integrally. As a result, the operation rod 26 and the cylinder 25 move integrally with respect to the fixed piston 29 fixed in the container, and the cylinder 25 and the fixed piston 29 move relative to each other. The space formed between the two is compressed.

  Next, as shown in FIG. 4b to FIG. 4c, when the breaking operation proceeds and the fixed arc contact 11 and the movable arc contact 21 are separated or opened, the arc space between the arc contacts 11 and 21 is An arc 30 is generated. When the interruption operation further proceeds and the current zero point is reached, a gas flow is supplied from the cylinder 25 to the arc 30 and finally the arc is extinguished as shown in FIG.

The conventional gas circuit breaker described above has the following problems.
In the case of a large current arc on the order of several kA, such as when an accidental current is interrupted, the distance between both arc contacts is sufficiently wide to form an appropriate flow path, and sufficient blowing pressure is accumulated in the cylinder 25. If not, the arc will not be extinguished even if the current zero point is reached.

  However, in the case of a small current arc of several hundreds A or less, such as an advanced small current interruption, the arc can be easily extinguished when the current zero point is reached even immediately after the opening (opening) of both arc contacts. Arced. Depending on the current phase, the arc time (the time that the arc between the arc contacts continues) is almost zero, the arc is extinguished immediately after the arc contacts are opened, and the distance between the arc contacts is extremely small. A recovery voltage from the grid is applied. When this breakdown voltage causes dielectric breakdown (re-ignition) between the arc contacts 11 and 21, overvoltage may occur, and the reliability of the system equipment is threatened. It is required to have an insulation recovery characteristic that is quick enough to avoid this.

  In order to avoid dielectric breakdown between the arc contacts 11, 21, generally, the electric field at the tip of the arc contacts 11, 21 is relaxed, or the speed at the time when the arc contacts 11, 21 are separated, That is, it is necessary to improve the opening speed and ensure quick insulation recovery between the arc contacts 11 and 21.

  However, if the drive speed is increased by increasing the driving force, the driving device becomes larger, or the weight of the movable contact portion increases to increase the mechanical strength, and the driving energy must be increased further. There was a problem.

  As an example of a method for dealing with such a problem, an invention 1 is disclosed in which the movable contact portion 20 of the circuit breaker and the opening / closing drive mechanism are connected via a fixed cam mechanism. According to the first aspect of the present invention, the speed after the opening can be improved by driving the link connected to the movable contact portion along the shape of the cam groove.

  In addition, as another countermeasure for the above-described problem, Invention 2 using a rotating groove cam and a connecting rod is also disclosed. According to the second aspect of the present invention, the rotating groove cam can be installed between the driving device and the movable contact portion, and the opening speed can be improved. If the system of this invention 2 is used, it is possible to further change the moving distance between the movable part on the driving device side and the movable contact part, and the moving distance of the movable part on the driving device side rather than the moving distance of the movable contact part. It is possible to reduce the drive energy efficiently by reducing.

JP 2002-208336 A JP 2004-55420 A

  However, in the countermeasure in which the movable contact portion of the circuit breaker and the open / close drive mechanism are connected via a fixed cam mechanism, the movable portion on the drive device side must be moved from the cam groove by the same amount as the movable contact portion. It is not efficient from the viewpoint of reducing driving energy. Further, in the recent market, the spring drive mechanism is oriented for ease of maintenance. Since the spring drive mechanism tends to increase the weight of the movable part from the structure of the hydraulic drive apparatus conventionally used, it is not efficient to move the movable part on the drive apparatus side by the same amount.

  In the case of a countermeasure using a rotating groove cam and a connecting rod, if the required speed is large, the mechanical strength of the groove cam has to be increased. Cannot be reduced. Furthermore, a damper and a stopper for the rotational motion of the rotating groove cam are required, and the structure may be complicated.

  In view of the above-described problems of the prior art, an object of the present invention is to provide a gas circuit breaker that applies a driving method for reducing driving energy and improving the opening speed in advanced small current interruption. And

  In order to achieve the above-mentioned object, the embodiment of the present invention arranges the first contact portion and the second contact portion on the central axis facing each other in a sealed container filled with an arc extinguishing gas, At least the first contact portion is configured to be driven by the operation mechanism portion at the time of the shut-off operation and the closing operation, and the first arc contact and the second arc contact are respectively connected to the first contact portion and the second contact portion. The first arc contactor and the second arc contactor are in contact conduction state during normal operation, and constitute an arc space that generates an arc in the space between the two contactors by being separated during the interruption operation, The first contact portion has a pressure accumulation space that generates a gas flow that extinguishes the arc by being accumulated by a thermal pressure increase action or a mechanical compression action from the arc space in the interruption operation process, and the pressure accumulation space is Has opening And communicated directly or indirectly to the upstream gas passage through the opening, and the upstream gas passage communicates with the arc space and has the same pressure as the filling pressure in the arc space and the sealed container. In the gas circuit breaker having the downstream gas flow path connecting the downstream space defined as the space, a pin fixed to the end of the first contact portion between the first contact portion and the operation mechanism portion Is fixedly supported by a fixed cam plate formed with a guide groove for guiding in the moving direction of the first contact portion, and at one end portion as a fulcrum at a position appropriately spaced in a direction orthogonal to the guide groove. In addition, an elongated hole for loosely fitting a pin fixed to the end portion of the first contact portion is formed at the other end portion, and an arm ratio control function including an intermediate portion connected to the operation mechanism portion is provided. From the fulcrum of the rotating lever to the slot Arm length of L1, when said arms length from the fulcrum of the rotating lever to the middle part was L2, L1 / L2 and arm ratio X, characterized in that the arm ratio X variable in opening operation.

Sectional drawing which shows the injection state of the gas circuit breaker which concerns on Embodiment 1 of this invention. Sectional drawing which shows the state which the interruption | blocking operation | movement of the gas circuit breaker concerning Embodiment 1 of this invention advanced. Sectional drawing which shows the state which the interruption | blocking operation | movement of the gas circuit breaker concerning Embodiment 1 of this invention was completed. The top view of the fixed guide plate employ | adopted as the gas circuit breaker which concerns on Embodiment 1 of this invention. It is a figure which compares the operation | movement performance of the gas circuit breaker which concerns on Embodiment 1 of this invention, and a prior art, (a) is a comparative example figure of the movement distance from an on state to a interruption | blocking state, (b) is a movement distance. The comparative example figure shown with the waveform. An axial direction sectional view showing some gas circuit breakers concerning Embodiment 2 of the present invention. Sectional drawing which shows the injection state of the gas circuit breaker which concerns on a prior art. Sectional drawing which shows the state which the interruption | blocking operation | movement of the gas circuit breaker concerning a prior art advanced. Sectional drawing which shows the further advanced state of the interruption | blocking operation | movement of the gas circuit breaker which concerns on a prior art. Sectional drawing which shows the state which the interruption | blocking operation | movement of the gas circuit breaker concerning a prior art was completed.

  Hereinafter, an embodiment according to a gas circuit breaker of the present invention will be described with reference to the drawings. In addition, the description which overlaps suitably is abbreviate | omitted suitably by attaching | subjecting the code | symbol same or related to the part which is common in each figure including the figure of a prior art.

[Embodiment 1]
1a to 1c are cross-sectional views showing the state of the gas circuit breaker according to Embodiment 1 of the present invention, FIG. 1a is a cross-sectional view showing a closing state before the breaking operation, and FIG. 1b is an arc contact when the breaking operation starts. FIG. 1 c is a cross-sectional view showing a state immediately after the child is opened, and FIG. FIG. 1d is a plan view of the fixed guide plate.

(Constitution)
1a to 1d, the basic configuration of the gas circuit breaker according to the first embodiment is the same as that of the prior art shown in FIG. 4, except that the insulating rod 27 of the movable contact portion 20 and an operation (not shown) are performed. The “arm ratio control function” is provided between the mechanism unit.

Here, the arm ratio control function is constituted by the following parts.
That is, the fixed cam plate 40 having a curved guide groove 40a extending in the pulling direction of the operation rod 26 between the insulating rod 27 of the movable contact portion 20 and the operation mechanism portion (not shown), and the fixed cam plate 40 One end of the pivot lever 50 is swingably supported by a fulcrum pin 60 at a predetermined distance in a direction orthogonal to the guide groove 40a, and the end of the insulating rod 27 has an elongated hole 50a at the other end. A pin 61 is fixed to the shaft, and the pin 61 is loosely fitted into both the long hole 50a and the guide groove 40a to connect the end of the insulating rod 27 and the end of the rotating lever 50, and the rotating lever. An arm ratio control function is constituted by a drive rod 51 connected to an operation mechanism unit (not shown) via a pin 62 at an intermediate portion of 50.

  The fixed cam plate 40 and the fulcrum pin 60 are fixed to appropriate portions of a sealed container (not shown).

The curved guide groove 40a described above is a large arc (radius is R2) groove substantially parallel to the center line cl of the operation rod 26, which is the center axis of the movable contact portion 20, as shown in detail in FIG. The large arcuate groove is composed of two small arcs (radius R1, R3) that are continuously and smoothly connected to both ends. Here, a relationship of R1 <R2, R3 <R2, and R1 = R3 is established between the radius R2 of the large arc groove and the radii R1 and R3 of the small arc groove. A line connecting both ends of the guide groove 40a is disposed on the axial center line cl of the operating rod 26, and a line vl connecting the center portion of the large arc-shaped groove and the fulcrum pin 60 of the rotating lever 50. Is orthogonal to the axial center line cl. That is, the guide groove 40a is formed symmetrically with respect to the vertical line vl.
Instead of the large arc (radius R2) groove, a linear groove substantially parallel to the axial center line cl of the operating rod 26 may be provided.

  Here, with respect to the rotating lever 50, the arm length L1 on the movable contact portion 20 side is the length from the fulcrum pin 60 to the center of the end pin 61, and on the other hand, the arm length L2 on the operation mechanism 4 side. Is the length from the fulcrum pin 60 of the rotating lever 50 to the center of the pin 62 at the connecting portion with the drive rod 51, and is configured such that L1 ≧ L2 in the blocking operation. L1 / L2 is referred to as an arm ratio X.

  In the first embodiment, the pin 61 moves in the elongated hole 50a and the guide groove 40a with the rotation of the rotation lever 50 in the blocking operation process, thereby changing the arm length L1 on the movable contact portion 1 side. Along with this, the arm ratio X (= L1 / L2) becomes variable.

In Embodiment 1, the arm ratio X of breaking operation early and X _0, when the arm ratio of the time of opening of the movable arc contact 21 and the fixed arc contact 11 and the X _1, X 0 _{<X 1} , the dimension of the long hole 50a and the shape of the guide groove 40a are considered in advance.

(Function)
Hereinafter, the operation of the first embodiment will be described.
In the state where the gas circuit breaker shown in FIG. 1a is turned on, when a small current interruption operation starts, the drive rod 51 connected to the operation mechanism unit (not shown) is pulled to the right side in the drawing by the intermediate portion of the rotation lever 50. The insulating rod 27 connected to the end of the rotating lever 50 via the pin 61 is also pulled. As a result, the movable contact portion 20 moves integrally in the arrow direction via the hollow operation rod 26 connected to the insulating rod 27.

  As the movable contact portion 20 moves, the operation rod 26 and the cylinder 25 move integrally with respect to the fixed piston 29 that is fixed, so that a relative movement occurs between the cylinder 25 and the fixed piston 29, and the cylinder. 25, the annular space formed inside is mechanically compressed.

  During the blocking operation of FIG. 1b, the pin 61 that connects the insulating rod 27 and the rotation lever 50 through the long hole 50a moves upward in the long hole 50a and moves in the arcuate guide groove of the fixed cam plate 40. It is guided in 40a. The arm length L2 between the pin 61 and the fulcrum pin 60 of the drive rod 51 connected to the operation drive unit (not shown) is selected to be shorter than the arm length L1 on the movable contact part 1 side. The moving distance of the movable part on the apparatus side is shorter than the moving distance of the movable contact part 20. Therefore, since the moving distance on the driving device side can be made shorter than the moving distance required from the insertion to the closing of the movable contact portion 20, it is possible to reduce the driving energy.

  Further, by making the arm ratio X at the time of opening the movable arc contact 21 and the fixed arc contact 11 in FIG. 1b larger than the arm ratio X in the closing state in FIG. The force for driving the unit 20 can be increased.

  As a result, the movable contact portion 20 accelerates quickly, and at the time when the movable arc contact 21 and the fixed arc contact 11 are separated, the driving force is reduced and the moving distance can be increased to enable high-speed control. Become.

  Further, since the large circular groove having the radius R2 located in the middle portion of the guide groove 40a is substantially parallel to the pulling direction, the operation of the movable contact portion 20 is maintained at a high speed. Since the guide groove 40a is symmetric with respect to the vertical line vl, the arm ratio X is gradually reduced and the speed is reduced when the cut-off state of FIG. 1c is reached.

Next, the performance of the gas circuit breaker according to Embodiment 1 and the conventional gas circuit breaker will be compared with reference to FIG.
FIG. 2A shows a case where the fixed cam plate 40 having the rotation lever 50 and the guide groove 40a according to the first embodiment is provided for the movement distance from the closing state to the shut-off state, as in the conventional technique. This is a comparison of the blocking operation with the case where only the lever is provided.

  The portion indicated by the solid line in the upper half of the insulating rod 27 means the closed state, and the portion indicated by the dotted line in the lower half means that it is in the cut-off state. Further, although the fixed cam plate 40 and the guide groove 40a are not shown, the center point of the pin 61 of the connecting portion of the insulating rod 27 and the rotation lever 50 rotates the locus 70 when moving along the guide groove 40a. As shown for each angle θ, the movable contact portion 20 moves in correspondence with the rotation angle θ like the movement distance 71 from the input state to the shut-off state corresponding to the locus 70.

  A locus 73 is a movement distance on the drive device side (not shown). The moving distance 71 is based on the center of the pin 28 of the connecting portion between the operating rod 26 and the insulating rod 27. The moving distance 72 is the moving distance of the movable contact portion 1 in the conventional driving method.

FIG. 2B is a waveform diagram showing each moving distance in relation to time.
In the case where only the pivot lever is provided as in the prior art, the speed is substantially constant as indicated by reference numeral 75. On the other hand, when the rotating lever 50 and the fixed cam plate 40 with the guide groove 40a are installed as in the first embodiment, the moving distance is small between the opening point and the end of the stroke as described above, as indicated by reference numeral 74, and the speed. Becomes slower. However, after the opening point that affects the advance small current interruption, the moving distance is large, and the opening speed can be improved.

(effect)
As described above, the gas circuit breaker according to the first embodiment is provided with the fixed cam plate 40 having the guide groove 40a and the rotating lever 50 between the movable contact portion 20 and the operation mechanism portion. Since the ratio control function is provided, not only can the driving energy be reduced, but the movable contact portion 20 is accelerated at a high load at the beginning, and the movable arc contact 21 and the fixed arc contact 11 are separated. The time can be driven at high speed. Therefore, even if the drive device is enlarged or the mechanical strength is not increased to increase the drive energy, a quick insulation recovery can be obtained and a good advance and small current interrupting performance can be obtained. Can be realized.

[Embodiment 2]
Next, a gas circuit breaker according to Embodiment 2 of the present invention will be described with reference to FIG.
(Constitution)
FIG. 3 is a cross-sectional view of the gas circuit breaker according to the second embodiment when the rotary lever 50 and its peripheral parts are viewed in the axial direction.

  In the case of the first embodiment described above, the arm lengths L1 and L2 are configured using the end portion and the intermediate portion of one rotation lever 50. However, in the second embodiment, the rotation lever is provided with the arm length L2. The first turning lever 50A and the second turning lever 50B having an arm length L1 are divided into a single piece and the turning levers 50A and 50B are integrally coupled by a turning shaft 50C. Moreover, in the second embodiment, the rotation shaft 50C is configured to pass through the gas filling container 80 via the gas seal 81, so that the first rotation lever 50A is rotated from the outside of the gas filling container 80. Accordingly, the second turning lever 50B disposed inside the gas space can be turned.

  Also in the case of the second embodiment, the arm length L1 on the movable contact portion 20 side, the arm length L2 on the drive mechanism side, and the arm ratio X are the same as those in the first embodiment, and other components are also shown in FIGS. Since it is the same as that shown by 1d, illustration is abbreviate | omitted.

  In the case of the second embodiment, the center line of the rotation shaft 50C corresponds to the position of the fulcrum by the fulcrum pin 60 of the first embodiment described above. Then, outside the gas filling container 80, the drive rod 51 is connected via the pin 62 from the rotation center line of the first rotation lever 50A to the position of the arm length L2. On the other hand, inside the gas filling container 80, the operation rod 26 is connected via the pin 61 from the rotation center line of the second rotation lever 50B to the position of the arm length L1.

(Function and effect)
The gas circuit breaker according to Embodiment 2 includes a fixed cam plate 40 having a guide groove 40a between the movable contact portion 20 and the operation mechanism portion, the first rotation lever 50A, the second rotation lever 50B, and both. Since the arm ratio control function is configured by the rotation shaft 50C integrally connecting the rotation lever, in addition to the same effects as the first embodiment, in addition to the gas filling container 80 of the rotation shaft 50C. By applying the gas seal 81 to the portion that penetrates the friction, the friction of the seal portion when a load perpendicular to the operation axis of the movable contact portion 20 is generated can be reduced, and the breaking operation speed (opening speed) can be reduced. It is possible to improve. Therefore, in the case of the second embodiment as well, it is possible to realize a circuit breaker that can quickly recover the insulation without increasing the driving energy and can obtain a good advanced small current interrupting performance.

[Other Embodiments]
Although the puffer type gas circuit breaker has been described in the embodiment described above, the present invention is not limited to the puffer type gas circuit breaker, but is a type using a so-called self-effect that obtains upstream pressure accumulation using arc energy. It can also be applied to other gas circuit breakers.

  In the embodiment described above, the fixed side contact portion 10 is described as being fixed to the sealed container. However, both the fixed side contact portion 10 and the movable contact portion 20 are moved in the reverse direction by the operation mechanism portion. You may do it.

  Furthermore, the embodiment described above is presented as an example, and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Fixed side contact part (2nd contact part), 11 ... Fixed arc contact, 12 ... Fixed electricity supply contact, 13 ... Support, 14 ... Support part, 14a ... Opening part, 20 ... Movable contact part ( 1st contact portion), 21 ... movable arc contact, 22 ... movable energizing contact, 23 ... insulating nozzle, 24 ... movable energizing contact, 25 ... cylinder, 25a ... opening, 26 ... operating rod, 26a ... opening 27, insulating rod, 28, pin, 29 ... fixed piston, 29a ... piston support, 29b ... support, 30 ... arc, 40 ... fixed cam plate, 40a ... guide groove, 50 ... rotating lever, 50a ... Long hole, 50A ... first turning lever, 50B ... second turning lever, 50C ... turning shaft, 51 ... drive rod, 60 ... turning lever fulcrum pin, cl ... movable contact center axis, 61 ... pin, 62 ... pin, 70 ... trajectory, 71 Moving distance of movable contact part by rotating lever, 72: Conventional moving distance of moving contact part, 73: Trajectory, 74: Moving distance of moving contact part by rotating lever (relation with time), 75: Conventional moving distance Contact part moving distance (relationship with time), 80 ... gas-filled container, 81 ... gas seal.

Claims (5)

A first contact part and a second contact part are arranged opposite to each other on a central axis in a sealed container filled with an arc-extinguishing gas, and at least the first contact part is turned off and inserted by an operation mechanism part. A first arc contact and a second arc contact are provided in the first contact portion and the second contact portion, respectively, and the first arc contact and the second arc contact are configured to be driven during operation. During normal operation, it is in a contact conduction state, and during the breaking operation, it is separated to constitute an arc space that generates an arc in the space between both contacts, and the first contact portion is separated from the arc space in the breaking operation process. A pressure accumulating space for generating a gas flow that extinguishes the arc, the pressure accumulating space being accumulated by a thermal pressure increasing action or a mechanical compression action, the pressure accumulating space having an opening and the opening to the upstream gas flow path; Through The downstream gas flow path is connected directly or indirectly, and the upstream gas flow path is connected to the arc space and connects the arc space and a downstream space defined as a space having the same pressure as the filling pressure in the sealed container. In a gas circuit breaker having
A fixed cam plate between the first contact portion and the operation mechanism portion, in which a pin fixed to an end portion of the first contact portion forms a guide groove that guides in the moving direction of the first contact portion; A pin fixed to the end portion of the first contact portion is loosely fitted to the other end portion while being supported to be swingable at one end portion as a fulcrum at a position that is appropriately spaced in a direction orthogonal to the guide groove. An arm ratio control function is provided which is formed with a long hole and an intermediate part is connected to the operation mechanism part. The arm length from the fulcrum of the rotation lever to the long hole is L1, and the rotation lever A gas circuit breaker in which the arm ratio X is made variable in the breaking operation when the arm length from the fulcrum to the intermediate portion is L2 and L1 / L2 is the arm ratio X. Regarding the arm ratio X of the rotating lever, when the arm ratio X at the initial stage of the breaking operation is X ₀ and the arm ratio X ₁ at the time when the first arc contactor and the second arc contactor are separated is X _0. 2. The gas circuit breaker according to claim _{1, wherein} the relationship of <X1 is established.   A line connecting the start end and the end of the guide groove is on the central axis of the first contact portion of the gas circuit breaker, and a line connecting the intermediate point from the start end to the end of the guide groove and the fulcrum of the rotating lever. The gas circuit breaker according to claim 1, wherein the gas circuit breaker is orthogonal to the above.   The gas circuit breaker according to any one of claims 1 to 3, wherein the rotating lever is provided in the sealed container.   The rotary lever is divided into a first rotary lever having an arm length L2 and a second rotary lever having an arm length L1, and the rotary levers are coupled together by a rotary shaft so that the second rotary lever is connected. The gas circuit breaker according to any one of claims 1 to 3, wherein a lever is housed in the sealed container, and the second rotating lever is disposed in the atmosphere.

Images