JPH03219515A - Buffer-type gas circuit-breaker - Google Patents

Abstract

PURPOSE:To make it unnecessary to enlarge operational force of a driving rod inresponse to a rated shut current by installing a non-return valve and passing only gas flow toward a gap part separated from a main buffer chamber. CONSTITUTION:An auxiliary buffer chamber 16 having a plurality of through holes 16A connected to a separated gap part 9 divided separately from a main buffer chamber 60 is formed in the inside of a buffer cylinder 50. A gas 14E in the gap part 9 is expanded by heat of an arc 15 and flows into the buffer chamber 16 through a space between insulated nozzles 10A, 10C. At that time, due to a non-return valve 17, the gas does not flow into the buffer chamber 60 and even when shut current increases, gas pressure increase in the buffer chamber 60 due to arc heat does not occur. Consequently, independent of the resisting force of a driving rod 12, a large amount of the gas 14E is generated in the buffer chamber 16 when a fixed contactor 3 escapes from the throat part 10 of nozzle 10A. The gas low 14A extinguishes the arc 15 and thus operational force of the driving rod does not need to be enlarged even at the time of rated current shut.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a buffer type gas circuit breaker used as a large-capacity power circuit breaker, and particularly to the structure of the arc extinguishing chamber.

[Conventional technology]

Buffer-type gas circuit breakers compress arc-extinguishing gas and spray this compressed gas into the opening gap of the interrupting part to extinguish the generated arc and interrupt large currents. SF is an excellent gas, and is even used in ultra-high pressure, large-capacity circuit breakers.

FIG. 3 is a vertical cross-sectional view showing the main part configuration of a conventional buffer type gas circuit breaker. Fixed contact 3 supported from the left side of 1 via insulator 2
, a movable contact 4 that can be brought into contact with and separated from this, a buffer cylinder 5 interlocked with this, a main buffer chamber 6 formed within this buffer cylinder 5, and a main buffer chamber 6 formed from the right side of the metal container 1 through an insulator 7. Supported fixed piston 8 and movable contact 4
The movable contact 4 moves in the X direction when the current is cut off, thereby guiding the gas compressed in the main buffer chamber 6 to the separation gap 9 between the fixed contact 3 and the movable contact 4. It is heated by the arc 15 between the insulating nozzle IOA, the second insulating nozzle IOB, and the fixed/movable contact provided on the opposite side of the movable contact 4 to the central axis of the main buffer chamber 6. The free space 1 inside the metal container 1
A cylindrical drive rod 12 provided with an exhaust passage 12A for discharging air to the current interrupting section 1 is housed as a main component of the current interrupting section.

When the current is cut off, when the driving force in the X direction is transmitted from the drive device (not shown) through the insulating rod 13, the movable contact 4, which is an integrated movable part, moves to the first insulating nozzle 10.
A. In a state where the second insulating nozzle IOB, the drive rod 12 and the buffer cylinder 5 move in the X direction and the fixed contact 3 does not escape from the throat portion 10 of the first insulating nozzle IOA, as shown in the figure, The plurality of sprays compressed by the fixed piston 8 in the main buffer chamber 6 flow from the hole 5A through the gap between the first insulating nozzle IOA and the second insulating nozzle IOB, separating the fixed contact 3 and the movable contact 4. The gas flow 14A blowing across the gap 9 cools the arc 15 generated in the separated gap 9, and the gas heated by the arc 15 flows through the exhaust passage 12A into the gas flow 14B.

14C and is discharged into the free space 11. As the breaking current increases, the arc 15 increases and the exhaust passage 1
Since the inlet of the main buffer chamber 2A is attempted to be blocked, the gas flow 14A from the main buffer chamber 6 tends to be difficult to flow. Therefore, the gas pressure in the main buffer chamber 6 has a large cutoff current (
It rises as it becomes.

Such an arc extinguishing method, that is, a method in which the inlet side of the exhaust passage 12A is somewhat blocked by the arc 15 at the initial stage of current cutoff, and the pressure rise in the buffer chamber 6 is thickened (the arc is extinguished by puf
It is called a buffer shape, which comes from the f meaning "to blow out".
The fixed contact 3 is the throat part 1 of the first insulating nozzle IOA.
It is used as a large current circuit breaker because it can spray a large amount of gas onto the arc 15 when it escapes from zero.

[Problem to be solved by the invention]

However, as mentioned above, in the conventional device, the pressure in the main buffer chamber 6 increases due to arc heat as the interrupting current increases, so the gas in the main buffer chamber 6 is compressed by the fixed piston 8 against this increase. Drive rod 1
There was a drawback that the operating force of No. 2 had to be increased as the breaking current increased.

If this operating force is small, the reaction force against the gas pressure will be insufficient, and the speed of separation between the fixed contact 3 and the movable contact 4 will decrease, and in extreme cases, the movable contact 4 will be pushed back in the X direction. A retrograde phenomenon occurs and it becomes impossible to shut off. Therefore, the drive device in the conventional device was equipped to provide an operating force determined by the rated breaking current of the circuit breaker.

An object of the present invention is to provide an apparatus in which the interior of the puff cylinder is divided into two chambers, so that even if the interrupting current increases, there is no need to increase the operating force of the drive rod accordingly.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, a fixed contact, a movable contact that can be brought into and out of contact with the fixed contact, and a buffer interlocked with the movable contact are arranged in a metal container filled with an arc-extinguishing gas. A cylinder, a fixed piston forming a main buffer chamber in the cylinder, and a blower provided on the opposite side of the buffer cylinder to the fixed piston, which surrounds the movable contact and transfers the gas compressed in the main buffer chamber. is equipped with an insulating nozzle that leads from the hole to the separation gap of the fixed/movable contact, wherein the cylinder is partitioned so as not to communicate with the main buffer chamber, and there is a communication port that communicates with the separation gap. An auxiliary buffer chamber provided with a hole is provided, and a check valve is provided at the outlet of the hole to allow only the gas flow from the main buffer chamber toward the separation gap to pass through.

Moreover, according to the present invention, in order to solve the above problems,
In a metal container filled with arc-extinguishing gas, a fixed contact, a movable contact that can be moved into and out of contact with the fixed contact, a buffer cylinder that is interlocked with the movable contact, and a main buffer chamber formed within the buffer cylinder. A blower provided on the side of the buffer cylinder opposite to the fixed piston guides the gas surrounding the fixed piston and the movable contact and being compressed in the main buffer chamber to the gap between the fixed and movable contacts through a hole. In the one equipped with an insulating nozzle, an auxiliary buffer chamber and a blowing passage are arranged in the buffer cylinder adjacent to the side opposite to the fixed piston of the main buffer chamber, and the auxiliary buffer chamber does not communicate with the main buffer chamber. The blowing passage is partitioned into the main buffer chamber at both ends to pass a gas flow from the main buffer chamber to the separation gap. It is assumed that the chamber and the spray are connected to the hole.

[Effect]

According to the configuration of the present invention, an auxiliary buffer chamber is provided in the buffer cylinder so as to be partitioned so as not to communicate with the main buffer chamber, and is provided with a communication hole communicating with the separation gap, and the spraying is carried out at the outlet of the hole. By having a structure equipped with a check valve that allows only the gas flow from the main buffer chamber to the opening gap to pass through, the gas in the opening gap that has expanded due to arc heat can be removed from the main buffer chamber due to the check valve. It no longer flows into the auxiliary buffer chamber, but instead flows into the auxiliary buffer chamber through the communication hole. Therefore, there is no pressure increase in the main buffer chamber due to arc heat, so even if the breaking current increases, there is no need to increase the operating force of the drive rod.On the other hand, as the breaking current increases, arc heat causes the auxiliary buffer Since the gas pressure in the first chamber increases, when the fixed contact escapes from the throat of the first insulating nozzle, a large amount of gas stored in the auxiliary buffer chamber flows out through the communication hole and blows out the arc.

Further, according to the configuration of the present invention, there is an auxiliary buffer chamber adjacent to the main buffer chamber on the side opposite to the fixed piston in the buffer cylinder and partitioned off from the main buffer chamber, and a blowing gas in the main buffer chamber is guided to the hole. By adopting a structure in which a blowing passage is provided, the gas in the gap that has expanded due to the arc heat is difficult to flow to the main buffer chamber side due to the large flow resistance of the blowing passage, and most of the gas is It flows into the auxiliary buffer chamber side via the long way out.

Therefore, there is almost no pressure increase in the main buffer chamber due to arc heat, so even if the interrupting current increases, there is no need to increase the operating force of the drive rod.On the other hand,
As the breaking current increases, the gas pressure in the auxiliary buffer chamber rises due to arc heat, so when the fixed contact escapes from the throat of the first insulating nozzle, a large amount of gas stored in the auxiliary buffer chamber flows through the communication hole. It flows out and blows out the arc.

〔Example〕

The present invention will be explained below based on examples.

FIG. 1 is a cross-sectional view showing the main part configuration of a buffer type gas circuit breaker according to an embodiment of the present invention, in which a buffer cylinder 5
0 is provided with an auxiliary buffer chamber 16 that is partitioned off from the main buffer chamber 60 and is equipped with a plurality of communication holes 16A that communicate with the separation gap 9. An intermediate insulating nozzle IOC for guiding the gas flow 140, 148 from the buffer cylinder 50 is interposed between the insulating nozzle IOB and the main buffer chamber 60 for spraying. A valve body 17A consisting of a conical piece, a spring 17B, and a spring support 100 are arranged so that only the gas flow 140 directed toward the section 9 passes through.
A check valve 17 consisting of a nozzle portion 170 into which a valve body 17 fits
It is configured with 10. Note that detailed explanations will be omitted by using the same reference numerals for the same parts as in the conventional device.

In FIG. 1, the gas in the separation gap 9 expanded by the heat of the arc 15 passes through the gap between the first insulating nozzle IOA and the middle insulating nozzle 10C and enters the auxiliary buffer chamber 16 through the communication hole 16A. Although the gas pressure in the auxiliary buffer chamber 16 increases as the cutoff current increases, gas does not enter the main buffer chamber 60 due to the check valve 17, and the gas pressure in the main buffer chamber 60 increases due to arc heat. do not have. Therefore, even if the interrupting current increases, the reaction force of the drive rod 12 will not be affected much. Fixed contact 3 is the first
When the insulating nozzle IOA escapes from the throat portion 10, a large amount of gas flow 14E is generated from the auxiliary buffer chamber 16 and blows out the arc 15.

FIG. 4 is a characteristic line diagram showing the pressure characteristics in the buffer chamber at the time of current cutoff, and the horizontal axis is a time scale, from the drive start time t0 of the drive rod 12 to the opening start time 1+ of the separation gap 9. The vertical axis shows the pressure inside the buffer chamber. In the figure, a broken line 18 indicates the pressure characteristic curve of the main buffer chamber 6 in the conventional device shown in FIG. The dashed line 19 indicates the main buffer chamber 60.
The solid line 20 shows the pressure characteristic curve 20 of the auxiliary buffer chamber 16.

In FIG. 4, the main buffer chamber 6.60 is separated by the separation gap 9.
Before opening, the pressure is only mechanically compressed by the fixed piston 8, so the pressure rise characteristics are the same in both cases. However, after the opening start time t1, the inflow of gas expanded by the arc 15 causes The pressure in the buffer chamber 6 rises rapidly as shown in the pressure characteristic curve 18, and after rising to pressure P2, the pressure decreases because the fixed contact 3 escapes from the throat portion 10 of the first insulating nozzle IOA. On the other hand, the first
The pressure in the main buffer chamber 60 in the device of the illustrated embodiment is:
Since there is no inflow of gas by the check valve 17, the pressure rises only due to the mechanical compression of the fixed piston 8, and after the pressure rises to a pressure P as shown in the pressure characteristic curve 19, the fixed contact 3 moves to the first insulating nozzle. The pressure in the auxiliary buffer chamber 16 decreases as it escapes from the throat portion 10 of the IOA, but the pressure in the auxiliary buffer chamber 16 rises rapidly as shown in the pressure characteristic curve 20 due to the inflow of gas, and after rising to a pressure almost equal to Pg, the arc 15 is blown out. A gas flow 14B can be generated. The maximum pressure P2 of the pressure characteristic curve 1113.20 increases as the breaking current increases, but the maximum pressure P1 of the pressure characteristic curve 19 is smaller than Pg because it does not affect the breaking current, and as the fast acting current increases, Pg and Pl increase. The difference becomes larger.

As can be seen from FIG. 4, the maximum gas pressure in the auxiliary buffer chamber 16 increases to the same level as in the conventional device, so the interruption speed and current interruption ability do not decrease at all. Furthermore, even if the breaking current increases, there is no longer a need to increase the operating force of the drive rod 12 accordingly, so conventional devices, for example,
A drive device was provided in accordance with the rated breaking current of A, but with this invention, the operating force for the drive rod 12 is less than half that of the conventional device, making it possible to reduce the size of the drive device and reduce the operating force. By reducing this, the impact force generated on the gas circuit breaker itself at the time of circuit breakage becomes smaller, and the components of the gas circuit breaker also become more compact.

FIG. 2 is a sectional view showing the main part structure of a buffer type gas circuit breaker according to a different embodiment of the present invention. The buffer chamber 161, the main buffer chamber 61 and the spray hole 51A are connected to the spray passage 2.
1, and the auxiliary buffer chamber 161 has a plurality of communication holes 161A communicating with the separation gap 9. The same reference numerals are used for the same parts as in the conventional device, so that details will be explained. Further explanation will be omitted.

In FIG. 2, the gas in the separation gap 9 expanded by the heat of the arc 15 flows into the auxiliary buffer chamber 161 through the communication hole 161A, and the gas pressure in the auxiliary buffer chamber 161 increases as the breaking current increases. Since the passage 21 is narrow and long, there is a large flow resistance to the main buffer chamber 61 side, and the gas cannot enter the main buffer chamber 61 in a short period of time. There is almost no pressure increase.

Therefore, even if the interrupting current increases, the reaction force of the drive rod 12 will not be affected much. When the fixed contact 3 escapes from the throat portion 10 of the first insulating nozzle IOA, a large amount of gas flow 14F is generated from the auxiliary buffer chamber 161 and blows out the arc 15.

The blowing passage 161A serves as a substitute for the check valve 17 in the embodiment shown in FIG. This prevents inflation gas from flowing back into the main buffer chamber 61. Therefore, the pressure characteristics in the buffer chamber at the time of current interruption in the embodiment shown in FIG. 2 are almost the same as the characteristics in the embodiment shown in FIG. 1 in FIG. There isn't. Spraying is in aisle 1
The optimum width and length of the passage 161A will vary depending on the rated breaking current of the circuit breaker, but for example, in the case of a breaking rating of several tens of kA, the dimensions of the passage 161A should be approximately 5 in the radial direction.
fi, if the length is several tens of cranes, effective flow resistance will occur.

〔Effect of the invention〕

As described above, this invention provides an auxiliary buffer chamber in the buffer cylinder that is partitioned off from the main buffer chamber and is equipped with a communication hole that communicates with the separation gap, and the blowing is carried out at the outlet of the hole into the main buffer chamber. Equipped with a check valve that allows only the gas flow from the chamber to the separation gap to pass through, the conventional device has the disadvantage that the operating force of the drive rod must be increased as the cut-off current increases.
It is possible to provide a device that has sufficient arc extinguishing ability without increasing the operating force of the drive rod.

Therefore, even if the main buffer chamber and the auxiliary buffer chamber according to the present invention are constructed by dividing a buffer cylinder of the size of the conventional device in half, the same arc extinguishing ability can be obtained with less than half the operating force of the conventional device. This provides the advantage that the drive device can be made smaller, and the weight of the gas circuit breaker can also be reduced by making the components in the gas circuit breaker more compact.

In addition, this invention has a configuration in which an auxiliary buffer chamber and a passageway are arranged adjacent to the side opposite to the fixed piston of the main buffer chamber in the pump cylinder. This device can prevent the gas flow expanded by the thermal arc from flowing into the main buffer chamber, so it has sufficient arc extinguishing ability with a small drive device without using a check valve with a complicated mechanism. can be provided.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 and 2 are cross-sectional views showing the main structure of a buffer type gas circuit breaker according to different embodiments of the present invention;
FIG. 3 is a sectional view showing the main structure of a conventional buffer type gas circuit breaker, and FIG. 4 is a characteristic diagram showing the pressure characteristics within one chamber of the pants. 1: Metal container, 2: Insulator, 3: Fixed contact, 4: Movable contact, 5.50.51: Buffer cylinder, 6, 6
0. st: Main buffer room, 5A, 50A, 51A
: Blowout hole, 7: Insulating pipe, 8: Fixed piston, 9: Separation gap, 10 Niss throat, 10A: First insulating nozzle, 10B: Second insulating nozzle, 10C: Intermediate insulating nozzle, 11 : Free space, 12: Drive rod, 12A: Exhaust passage, 13: Insulating rod, 14A, 14B, 14
G. 7- 14D, 14B, 14F: Gas flow, 15: Arc,
16.161 = Auxiliary buffer chamber, 16^, tsla: Communication hole, 17: Check valve, 17A: Valve body, 17B Nispring, 17C Nispring support, 1711: Nozzle part,
18: Pressure characteristic curve of main buffer chamber 6, 19: Pressure characteristic curve of main buffer chamber 60, 20: Pressure characteristic curve of auxiliary buffer chamber 16, -18=

Claims (1)

[Claims] 1) A fixed contact, a movable contact that can be moved into and out of contact with the fixed contact, a buffer cylinder interlocked with the movable contact, and the buffer cylinder in a metal container filled with arc-extinguishing gas. A fixed piston forming a main buffer chamber therein, and a gas compressed in the main buffer chamber that surrounds the movable contact and passes through a blowing hole provided on the side opposite to the fixed piston of the buffer cylinder to the fixed/movable contact. An auxiliary device equipped with an insulating nozzle that leads to the separation gap of the child, wherein the buffer cylinder is partitioned so as not to communicate with the main buffer chamber, and is provided with a communication hole that communicates with the separation gap. 1. A buffer type gas circuit breaker, characterized in that a buffer chamber is provided, and a check valve is provided at the outlet of the blowing hole to allow only the gas flow from the main buffer chamber toward the separation gap to pass through. 2) In a metal container filled with arc-extinguishing gas, there is a fixed contact, a movable contact that can be brought into and out of contact with the fixed contact, a buffer cylinder that is interlocked with the movable contact, and a main buffer chamber inside the buffer cylinder. The gas compressed in the main buffer chamber surrounds the fixed piston to form and the movable contact, and the gas that is compressed in the main buffer chamber is supplied to the gap between the fixed and movable contacts through a blowing hole provided on the side opposite to the fixed piston of the buffer cylinder. An auxiliary buffer chamber and a blowing passage are arranged in the buffer cylinder adjacent to the side opposite to the fixed piston of the main buffer chamber, and the auxiliary buffer chamber is connected to the main buffer chamber. The blowing passage is partitioned so as not to communicate with each other, and includes a communication hole communicating with the separation gap, and the blowing passage has two holes at both ends so as to pass a gas flow from the main buffer chamber toward the separation gap. A buffer type gas circuit breaker, characterized in that the main buffer chamber and the blowing hole communicate with each other.