JP2011003290A - Gas-blast circuit breaker for power use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-blast circuit breaker for power use without an enlarged puffer cylinder, capable of quick arc-extinguishing and preventing reignition.SOLUTION: The gas-blast circuit breaker includes: the puffer cylinder 21; a fixed piston 24, outer diameters of which get gradually smaller towards a tip direction; a first compression chamber 26 formed of the puffer cylinder and the fixed piston; a movable piston 25, capable of moving along the axial direction by contacting the fixed piston; a second compression chamber 27, formed by an inner face of the puffer cylinder 21a and a separation wall 21c which is arranged inside of the puffer cylinder in a coaxial state, to which the movable piston engages in free movement in the axial direction; an energizing means 28 accommodated in the second compression chamber and energizes the movable piston towards the fixed piston; A first nozzle 31 to inject the arc extinguishing gas inside the first compression chamber to the arc E and; a second nozzle 32 to inject the arc extinguishing gas in the second compression chamber to the arc E.

Description

  The present invention relates to a power gas circuit breaker for interrupting a large current, and more particularly to a structure of a power gas circuit breaker that enhances the ability to extinguish an arc generated when a current is interrupted.

  Conventionally, there has been known a power gas circuit breaker in which the pressure of the arc extinguishing gas is mechanically increased by relatively moving the piston and the puffer cylinder, and the arc extinguishing gas whose pressure is increased is blown toward the arc. (See Patent Documents 1 and 2). In the gas circuit breaker of Patent Document 1, the compression area of the puffer chamber is reduced to reduce the reaction force of the hot gas generated on the arc side. In the gas circuit breaker of Patent Document 2, the puffer is operated with a small operating force. A sufficient pressure rise in the chamber and a sufficient spraying time are ensured.

JP-A-8-279325 JP-A-10-149552

By the way, in the power gas circuit breaker, it is desirable to extinguish the arc before the arc becomes large. For this purpose, it is necessary to quickly increase the pressure of the arc extinguishing gas at the initial stage of the interruption. When the arc cannot be quickly extinguished, the arc generating part of the puffer cylinder side and the stationary contact is melted by the heat of the arc to become metal vapor, the arc generating part is consumed, and the arc extinguishing gas SF by the heat of the arc There is a problem that ₆ changes in quality and the insulation resistance of the arc-extinguishing gas decreases. Furthermore, when the amount of arc-extinguishing gas injected is not sufficient, there is also a problem that the arc once extinguished reappears.

  In order to solve the above problems, it is necessary to increase the pressure of the arc-extinguishing gas that is injected toward the arc from the beginning of the interruption, and also ensure a sufficient amount of arc-extinguishing gas that is injected toward the arc. There is a need,

  However, in order to secure a sufficient amount of arc-extinguishing gas injected toward the arc, it is necessary to increase the diameter of the puffer cylinder. However, if the diameter of the puffer cylinder is simply increased, the puffer cylinder is stored. As a result, the gap between the pressure vessel and the pressure vessel is reduced, resulting in a new problem that the insulation performance between the puffer cylinder and the pressure vessel is lowered. In Patent Documents 1 and 2, it is possible to increase the pressure of the arc-extinguishing gas that is injected toward the arc in the early period of interruption, but it is not possible to ensure a sufficient amount of arc-extinguishing gas in the latter period of interruption. There is a possibility that the extinguished arc will recur.

  Accordingly, an object of the present invention is to provide a power gas circuit breaker that can quickly extinguish an arc without increasing the size of the puffer cylinder and can prevent the arc from re-arcing. And

  In order to achieve the above object, the invention according to claim 1 has a stationary contact that can contact the puffer cylinder side, and when shutting off, the puffer cylinder moves in a direction away from the stationary contact. A fixed piston that is fitted to the puffer cylinder so as to be movable in the axial direction and whose cross-sectional area in the axial direction changes stepwise, and the fixing of the puffer cylinder formed by the puffer cylinder and the fixed piston. Provided in the interior of the puffer cylinder, a first compression chamber whose axial cross-sectional area becomes smaller stepwise by movement toward the piston side, a movable piston movable in the axial direction by contact with the fixed piston, and A second wall formed by the circumferentially extending partition wall and the inner surface of the puffer cylinder is fitted with the movable piston so as to be movable in the axial direction. A compression chamber; an urging means that is housed in the second compression chamber and urges the movable piston toward the fixed piston; and the first compression chamber is compressed by the axial movement of the puffer cylinder. A first nozzle for injecting an arc gas toward an arc generated between the stationary contact and the puffer cylinder; and an arc-extinguishing gas in the second compression chamber compressed by the axial movement of the movable piston. And a second nozzle that injects the gas toward an arc generated between the stationary contact and the puffer cylinder.

  According to this invention, when the power gas circuit breaker is shut off, the puffer cylinder side and the stationary contact are brought into a non-contact state due to the movement of the puffer cylinder, and an arc is generated between the puffer cylinder side and the stationary contact. When the puffer cylinder moves, the arc-extinguishing gas in the first compression chamber is compressed, and the compressed arc-extinguishing gas is injected from the first nozzle toward the arc. Further, when the puffer cylinder is moved, the arc extinguishing gas in the second compression chamber is compressed by the axial movement of the movable piston due to contact with the fixed piston, and the compressed arc extinguishing gas is arced from the second nozzle. It is injected toward

  According to a second aspect of the present invention, in the power gas circuit breaker according to the first aspect, the fixed piston has a large-diameter portion that can contact the movable piston and a small-diameter portion that can enter the inside of the partition wall. The axial length of the small diameter portion and the axial length of the movable piston are set to be the same.

  According to a third aspect of the present invention, in the power gas circuit breaker according to the first or second aspect, the movable piston is formed with an axially extending skirt portion that contacts the inner surface of the puffer cylinder. It is characterized by.

  According to a fourth aspect of the present invention, in the power gas circuit breaker according to any one of the first to third aspects, the urging means is composed of a compression coil spring that is elastically deformable in the axial direction. The compression coil spring can be stored in a holding case portion formed at an end portion of the puffer cylinder.

  According to a fifth aspect of the present invention, in the power gas circuit breaker according to any one of the first to fourth aspects, the axial movement of the movable piston is applied to the axial end of the partition wall. A flange that bulges radially outward to be regulated is formed, and a gap is provided between the outer peripheral surface of the flange and the movable piston.

  According to the first aspect of the present invention, since the cross-sectional area of the first compression chamber decreases stepwise as the puffer cylinder moves toward the fixed piston, the first nozzle is directed to the arc. Thus, the pressure of the arc extinguishing gas ejected in this manner can be quickly raised, and the arc can be extinguished quickly. As a result, it is possible to avoid the arc generation part of the fixed contact and the puffer cylinder from being melted by the heat of the arc to become metal vapor, and to suppress the wear of the puffer cylinder side and the fixed contact due to the arc heat. it can. Furthermore, since the arc is extinguished quickly, the alteration of the arc extinguishing gas due to the heat of the arc can be suppressed, and the insulation resistance of the arc extinguishing gas can be maintained for a long time.

  Further, since the movable piston moves in the axial direction by contact with the fixed piston, the arc-extinguishing gas in the second compression chamber can be injected toward the arc through the second nozzle. It is possible to secure a sufficient amount of arc-extinguishing gas that is injected toward the arc, and it is possible to reliably prevent the arc that has been extinguished once from recurring.

  According to the second aspect of the present invention, the compression of the arc extinguishing gas in the first compression chamber by the small diameter portion of the fixed piston and the compression of the arc extinguishing gas in the second compression chamber by the movable piston can be started simultaneously. The arc extinguishing gas can be injected toward the arc from both the first nozzle and the second nozzle, and the arc extinguishing ability of the arc can be increased.

  According to the invention described in claim 3, since the movable piston is formed with the skirt portion extending in the axial direction in contact with the inner surface of the puffer cylinder, it is possible to prevent galling between the movable piston and the puffer cylinder, The movable piston can be smoothly moved in the axial direction.

  According to the fourth aspect of the present invention, the urging means is composed of a compression coil spring that is elastically deformable in the axial direction, and this compression coil spring can be stored in the holding portion formed at the end of the puffer cylinder. Therefore, the moving distance of the movable piston can be ensured long, and the volume of the second compression chamber can be increased.

  According to the fifth aspect of the present invention, since the gap is provided between the outer peripheral surface of the flange formed at the end of the partition wall and the movable piston, negative pressure is prevented from acting on the movable piston. The arc-extinguishing gas in the second compression chamber can be compressed smoothly.

It is a principal part expanded sectional view of the gas circuit breaker for electric power concerning embodiment of this invention. It is a principal part expanded sectional view which shows the state at the time of the interruption | blocking operation | movement of the electric power gas circuit breaker of FIG. It is sectional drawing which shows the whole structure of the power gas circuit breaker of FIG. It is principal part sectional drawing which shows the energization state in the gas circuit breaker for electric power of FIG. It is principal part sectional drawing which shows the state at the time of interruption | blocking operation | movement in the electric power gas circuit breaker of FIG. It is a characteristic view which shows the relationship between the pressure of arc-extinguishing gas and the breakdown voltage in the gas circuit breaker for electric power of FIG. It is a schematic diagram which shows the change of the volume of the 1st compression chamber in the gas circuit breaker for electric power of FIG. It is a schematic diagram which shows the position of the fixed piston with respect to the puffer cylinder of the interruption | blocking initial stage in the gas breaker for electric power of FIG. It is a characteristic view which shows the relationship between the position of the fixed piston in FIG. 8, and the pressure of arc-extinguishing gas. It is a schematic diagram which shows the position of the fixed piston with respect to the puffer cylinder in the middle of interruption | blocking in the gas circuit breaker for electric power of FIG. It is a characteristic view which shows the relationship between the position of the fixed piston in FIG. 10, and the pressure of arc-extinguishing gas. It is a schematic diagram which shows the position of the fixed piston with respect to the puffer cylinder of the late stage of interruption | blocking in the electric power gas circuit breaker of FIG. It is a characteristic view which shows the relationship between the position of the fixed piston in FIG. 12, and the pressure of arc-extinguishing gas.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 13 show an embodiment of the present invention. FIG. 3 shows the overall structure of the power gas circuit breaker 1. The power gas circuit breaker 1 has a cylindrical pressure vessel 2. At the upper part of the pressure vessel 2, hollow insulator portions 3 and 4 extending upward are provided. A rod-like conductive member 5 extending from the top of the insulator 3 to the inside of the pressure vessel 2 is disposed inside the insulator 3. Similarly, a rod-like conductive member 6 extending from the top of the insulator 4 to the inside of the pressure vessel 2 is disposed inside the other insulator 4. An arc extinguishing gas G is sealed in the pressure chamber 7 in the pressure vessel 2 in a compressed state. As the arc extinguishing gas G, SF ₆ (sulfur hexafluoride) having high insulating properties is used.

  In the pressure vessel 2, a fixed blocking part 10 connected to the conductive member 6 and a movable blocking part 20 connected to the conductive member 5 are arranged. A hydraulic drive device 8 for operating the movable blocking unit 20 is attached to the end of the pressure vessel 2. The hydraulic drive device 8 has a rod 9 connected to a puffer cylinder 21 described later. 4 and 5 show schematic structures of the fixed blocking unit 10 and the movable blocking unit 20. As shown in FIG. 4, the fixed blocking portion 10 has a fixed contact 12 provided inside a cylindrical frame 11 having a U-shaped cross section. The stationary contact 12 is formed in a bar shape extending in the horizontal direction. The stationary contact 12 is made of, for example, an alloy of silver and tungsten having a high conductivity and a high melting point.

  1 and 2 show details of the movable blocking portion 20. The movable blocking portion 20 mainly has a puffer cylinder 21, a fixed piston 24, a movable piston 25, a first nozzle 31, and a second nozzle 32. The puffer cylinder 21 is made of a cylindrical metal member having high conductivity, and has an end wall 21f at one end. The inner surface 21a of the puffer cylinder 21 is formed with high precision, and the surface is finished very densely. A fixed piston 24 is fitted to the inner surface 21a of the puffer cylinder 21 so as to be movable in the axial direction. The end wall 21f of the puffer cylinder 21 is provided with a movable contact (not shown) that can come into contact with the fixed contact 12 of the fixed blocking portion 10. The movable contact is always in contact with the outer peripheral surface of the stationary contact 12 except during the blocking operation. A plurality of insulating nozzles 22 are attached to the end wall 21 f of the puffer cylinder 21. The plurality of insulating nozzles 22 can be displaced in the radial direction around the fixed contact 12 and are arranged radially so as to surround the fixed contact 12 from the outer periphery.

  The fixed piston 24 is formed so that the cross-sectional area changes in two stages in the axial direction. The fixed piston 24 has a large-diameter portion 24a having a large outer shape and a small-diameter portion 24b having an outer shape formed smaller than the large-diameter portion 24a. The large diameter portion 24 a is movable in the axial direction in contact with the inner surface 21 a of the puffer cylinder 21. The gap formed between the outer surface of the large diameter portion 24a and the inner surface 21a of the puffer cylinder 21 is remarkably small so that gas leakage is minimized. The small-diameter portion 24b is formed continuously with the large-diameter portion 24a, and the outer surface 24b1 can contact an inner surface of a partition wall 21c described later.

  The gap formed between the outer surface of the small diameter portion 24b and the inner surface of the partition wall 21c is remarkably small so that gas leakage is minimized. The fixed piston 24 is formed with a through hole 24b3 extending along the axis C. A guide shaft 21b extending along the axis C from the end wall 21f of the puffer cylinder 21 is inserted through the through hole 24b3. The gap between the outer surface of the guide shaft 21b and the inner surface of the through hole 24b3 of the fixed piston 24 is extremely small so that gas leakage is minimized.

  The end surface 24a1 of the large diameter portion 24a of the fixed piston 24 comes into contact with the end wall 21f of the puffer cylinder 21 when the puffer cylinder 21 moves in the axial direction. The end surface 24b2 of the small diameter portion 24b of the fixed piston 24 comes into contact with the flange 21d of the partition wall 21c of the puffer cylinder 21 when the puffer cylinder 21 moves in the axial direction. The movable blocking part 20 is formed with a first compression chamber 26 and a second compression chamber 27. The first compression chamber 26 is configured such that the cross-sectional area in the axial direction is gradually reduced by the movement of the puffer cylinder 21 toward the fixed piston 24.

  Inside the puffer cylinder 21 is formed a partition wall 21c that faces the inner surface 21a of the puffer cylinder 21 and extends in the circumferential direction. In the movable blocking portion 20, a second compression chamber 28 is formed by the inner surface 21a of the puffer cylinder 21 and the partition wall 21c. A movable piston 25 is fitted in the second compression chamber 28 so as to be movable in the axial direction. The movable piston 25 has a disk-like piston main body 25a and a cylindrical holding portion 25d extending from the piston main body 25a to the fixed piston 24 side. A first skirt portion 25 c extending in the axial direction that contacts the inner surface 21 a of the puffer cylinder 21 is formed on the outer peripheral portion of the piston main body 25 a of the movable piston 25. Similarly, a second skirt portion 25b extending in the axial direction that contacts the inner surface of the puffer cylinder is formed on the outer peripheral portion of the tip of the holding portion 25d of the movable piston 25.

  The movable blocking portion 20 is provided with a compression coil spring 28 as an urging means for urging the movable piston 25 toward the fixed piston 24 side. One end of the compression coil spring 28 is always in contact with the piston body 25a of the movable piston 25. The other end of the compression coil spring 28 is always in contact with the end surface of the holding case portion 21 e formed at the end portion of the puffer cylinder 21. The compression coil spring 28 is elastically deformable in the axial direction. When the compression coil spring 28 is sufficiently compressed in the axial direction by the movement of the movable piston 25, the holding is formed at the end of the puffer cylinder 21 as shown in FIG. It can be stored in the case portion 21e.

  A flange 21d that bulges outward in the radial direction for restricting the axial movement of the movable piston 25 is formed at the axial end of the partition wall 21 of the puffer cylinder 21. A gap S between the outer peripheral surface of the flange 21 d and the holding portion 25 d of the movable piston 25 communicates with the first compression chamber 26. The gap S is for preventing negative pressure from acting on the piston body 25a side when the movable piston 25 moves to the end wall 21f side of the puffer cylinder 21.

  On the end wall 21 f of the puffer cylinder 21, the arc extinguishing gas G in the first compression chamber 26 compressed by the axial movement of the puffer cylinder 21 is placed between the fixed contact 12 and the end wall 21 f of the puffer cylinder 21. The first nozzle 31 that injects toward the arc E generated in the above is provided. Similarly, the arc-extinguishing gas G of the second compression chamber 27 compressed by the axial movement of the movable piston 25 due to contact with the fixed piston 24 is applied to the end wall 21 f of the puffer cylinder 21 with the fixed contact 12. A second nozzle 32 that injects toward the arc E generated between the end wall 21 f of the puffer cylinder 21 is provided.

  Next, the operation sequence and operation of the power gas circuit breaker 1 will be described.

  As shown in FIG. 4, when the power transmission system is normally operated, the stationary contact 12 of the power gas circuit breaker 1 and the movable contact (not shown) on the puffer cylinder 21 side are in contact with each other. A large current flows through the contact portion between the fixed contact 12 and the movable contact. For example, when a failure of the power transmission system occurs, the hydraulic drive device 8 operates and the puffer cylinder 21 moves to the fixed piston 24 side by the tensile force of the rod 9. Accordingly, the volume of the first compression chamber 26 is reduced, and the pressure of the arc extinguishing gas G1 in the first compression chamber 26 is increased.

FIG. 6 shows the relationship between the pressure and the breakdown voltage in SF ₆ as the arc extinguishing gas G sealed in the pressure vessel 2. As shown in FIG. 6, it can be seen that the breakdown voltage (insulation resistance) increases as the pressure of SF ₆ increases. It can also be seen that SF ₆ has better insulation resistance than air. FIG. 7 shows the relationship between the amount of movement of the puffer cylinder 21 and the cross-sectional area of the first compression chamber 26 in the axial direction. As the puffer cylinder 21 approaches the fixed piston 24, the shaft of the first compression chamber 26 is shown. It can be seen that the sectional area in the direction gradually decreases.

  FIGS. 8 and 9 show the relationship between the position of the puffer cylinder 21 and the pressure in the first compression chamber 26 at the initial cutoff of the power gas circuit breaker 1. In the initial stage of shut-off, the puffer cylinder 21 has moved to the position A1, and the pressure in the first compression chamber 26 at this time is at the pressure P1. In this state, since the flange 21d of the partition wall 21c of the puffer cylinder 21 does not reach the small diameter portion 24b of the fixed piston 24, the volume of the first compression chamber 26 is not reduced so much. Therefore, the pressure P1 in the first compression chamber 26 is slightly higher than that of the conventional power gas circuit breaker with the same axial sectional area of the fixed piston.

  FIGS. 10 and 11 show the relationship between the position of the puffer cylinder 21 and the pressure in the first compression chamber 26 in the middle of the cutoff of the power gas circuit breaker 1. In the middle of the shut-off, the puffer cylinder 21 has moved to the position A2, and the pressure in the first compression chamber 26 at this time is at the pressure P2. In this state, the flange 21d of the partition wall 21c of the puffer cylinder 21 moves to a position immediately before the end surface 24b2 of the small diameter portion 24b of the fixed piston 24, so that the volume of the first compression chamber 26 is significantly larger than the state of FIG. Reduced to Therefore, as shown in FIG. 11, the pressure P2 in the first compression chamber 26 is significantly increased as compared with FIG. As a result, the pressure in the first compression chamber 26 quickly rises from the initial period to the middle period, and the arc-extinguishing gas G <b> 1 whose pressure has increased is ejected from the first nozzle 31 toward the arc E.

  FIG. 12 and FIG. 13 show the relationship between the movement position of the puffer cylinder 21 and the pressure in the first compression chamber 26 in the late stage of shutoff of the power gas circuit breaker 1. In the late shut-off period, the puffer cylinder 21 has moved to the position A3, and the pressure in the first compression chamber 26 at this time becomes the pressure P3. In this state, since the small diameter portion 24b of the fixed piston 24 enters the inside of the partition wall 21c, the volume of the first compression chamber 26 is further reduced, and the pressure in the first compression chamber 26 is further increased. In the latter half of the shut-off period, the movable piston 25 contacts the end surface 24a1 of the large-diameter portion 24a of the fixed piston 24, so that the volume of the second compression chamber 27 is reduced by the movement of the movable piston 25 and compressed. The arc extinguishing gas G2 is ejected from the second nozzle 32 toward the arc E.

  Here, since the movable piston 25 is formed with axially extending skirt portions 25b and 25c that come into contact with the inner surface 21a of the puffer cylinder 21, it is possible to prevent squeezing between the movable piston 25 and the puffer cylinder 21. The movable piston 25 can be smoothly moved in the axial direction. Further, since the compression coil spring 28 can be stored in the holding portion 21e formed at the end portion of the puffer cylinder 21, a long moving distance of the movable piston 25 can be secured, and the second compression chamber 27 can be secured. The volume of can be increased. Furthermore, since the gap S is provided between the outer peripheral surface of the flange 21d formed at the end of the partition wall 21c and the movable piston 25, it is possible to prevent negative pressure from acting on the movable piston 25, The arc extinguishing gas G2 in the second compression chamber 27 can be compressed smoothly.

  When recovery from the failure of the power transmission system can be confirmed, the power gas circuit breaker 1 is closed. That is, by the closing operation of the power gas circuit breaker 1, the puffer cylinder 21 moves to the fixed contact 12 side, and the fixed breaker 10 and the movable breaker 20 are electrically connected. In this state, the movable contact (not shown) of the puffer cylinder 21 and the fixed contact 12 are completely in contact with each other, and the movable piston 25 is urged toward the fixed piston 24 by the compression coil spring 28. In addition, in a state where the movable contact (not shown) of the puffer cylinder 21 and the fixed contact 12 are in complete contact, a part of the arc extinguishing gas G in the pressure vessel 2 passes through the first nozzle 31. While flowing into one compression chamber 26, it flows into the second compression chamber 27 via the second nozzle 32.

  In this way, from the initial period to the middle period, the axial cross-sectional area of the first compression chamber 26 decreases stepwise due to the movement of the puffer cylinder 21 toward the fixed piston 24 side. The pressure of the arc extinguishing gas G1 ejected toward the arc E can be quickly increased, and the arc E can be extinguished quickly. As a result, it can be avoided that the arc generating portions of the fixed contact 12 and the puffer cylinder 21 are melted by the heat of the arc E and become metal vapor, and the puff cylinder 21 side and the fixed contact 12 are consumed by the arc heat. Can be suppressed. Furthermore, since the arc E is extinguished rapidly, the alteration of the arc extinguishing gas G in the pressure vessel 2 due to the heat of the arc E can be suppressed, and the insulation resistance of the arc extinguishing gas G can be maintained for a long time. Can do.

  Further, the arc-extinguishing gas G <b> 2 in the second compression chamber 27 can be injected toward the arc E through the second nozzle 32 by the movement of the movable piston 25 in the axial direction by contact with the fixed piston 24. Therefore, it becomes possible to secure a sufficient injection amount of the arc extinguishing gas G2 to be injected toward the arc E, and it is possible to reliably prevent the arc E once extinguished from recurring.

  Furthermore, since the axial length of the small diameter portion 24b of the fixed piston 24 and the axial length of the movable piston 25 are the same, the arc extinguishing gas G1 in the first compression chamber 26 by the small diameter portion 24b of the fixed piston 24 is the same. The compression and the compression of the arc-extinguishing gas G2 in the second compression chamber 28 by the movable piston 25 can be started simultaneously, and the arc-extinguishing gas is directed toward the arc E from both the first nozzle 31 and the second nozzle 32. G1 and G2 can be injected at the same time, and the arc extinguishing ability of the arc E can be enhanced.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to the above-described embodiment, and even if there is a design change or the like without departing from the gist of the present invention, It is included in this invention. For example, the fixed piston 24 is formed with a large-diameter portion 24a and a small-diameter portion 25b, and the axial cross-sectional area is changed in two steps. However, the fixed piston 24 may have a structure with three or more steps.

DESCRIPTION OF SYMBOLS 1 Electric power circuit breaker 8 Hydraulic drive device 10 Fixed interruption | blocking part 12 Fixed contactor 20 Movable interruption | blocking part 21 Puffer cylinder 21c Partition wall 21d Flange 24 Fixed piston 24a Large diameter part 24b Small diameter part 25 Movable piston 25b, 25c Skirt part 26 1st One compression chamber 27 Second compression chamber 28 Compression coil spring (biasing means)
31 First nozzle 32 Second nozzle C Center axis E Arc G Arc extinguishing gas S Clearance

Claims (5)

A power gas circuit breaker having a stationary contact that can come into contact with the puffer cylinder side, wherein the puffer cylinder moves in a direction away from the stationary contact when shut off,
A fixed piston that is fitted to the puffer cylinder so as to be movable in the axial direction, and in which the axial sectional area changes stepwise;
A first compression chamber formed by the puffer cylinder and the fixed piston, the axial cross-sectional area of which is gradually reduced by the movement of the puffer cylinder toward the fixed piston;
A movable piston movable in the axial direction by contact with the fixed piston;
A second compression chamber formed by a circumferentially extending partition wall provided in the puffer cylinder and an inner surface of the puffer cylinder, the movable piston being fitted to be movable in the axial direction;
A biasing means housed in the second compression chamber and biasing the movable piston toward the fixed piston;
A first nozzle that injects an arc-extinguishing gas in the first compression chamber compressed by the axial movement of the puffer cylinder toward an arc generated between the fixed contact and the puffer cylinder;
A second nozzle that injects an arc extinguishing gas in the second compression chamber compressed by the axial movement of the movable piston toward an arc generated between the fixed contact and the puffer cylinder;
A gas circuit breaker for electric power, comprising:   The fixed piston has a large-diameter portion that can contact the movable piston and a small-diameter portion that can enter the inside of the partition wall. The axial length of the small-diameter portion and the axial direction of the movable piston The gas gas circuit breaker for electric power according to claim 1, wherein the lengths are set to be the same.   3. The power gas circuit breaker according to claim 1, wherein the movable piston is formed with an axially extending skirt portion that contacts an inner surface of the puffer cylinder. 4.   The biasing means is composed of a compression coil spring that is elastically deformable in the axial direction, and the compression coil spring can be stored in a holding case portion formed at an end portion of the puffer cylinder. The power gas circuit breaker according to any one of claims 1 to 3.   A flange that bulges outward in the radial direction for restricting the axial movement of the movable piston is formed at the axial end of the partition wall, and is formed between the outer peripheral surface of the flange and the movable piston. 5. The power gas circuit breaker according to claim 1, wherein a gap is provided in the power gas breaker.

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