JPS6079629A - Buffer type gas breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention provides a method for forming a buffer chamber between a fixed contact, a movable contact, and a fixed piston in a container filled with arc-extinguishing gas. A buffer cylinder that compresses the gas in the buffer chamber in cooperation with the movable contact, and a fixed and movable cylinder that surrounds the movable contact and is attached to the end face of the buffer cylinder on the fixed contact side and compresses the compressed gas. The present invention relates to a measure for improving the breaking performance of a buffer type gas circuit breaker, which is equipped with an insulating nozzle equipped with a throat portion that guides gas into a separation gap of a contact and from which the guided gas is ejected.

[Prior art and its problems]

As a conventional buffer type gas trace breaker, for example, the one shown in FIG. 1 is known. The figure shows the closing state of the circuit breaker, and during normal use, the current flowing from one main terminal 2a of this circuit breaker flows from the sealed metal container l to the bushing conductor 2b, which is insulated and supported by the bushing 2. ,
A fixed contact base 4 that is electrically connected to the conductor 2b and has a fixed contact 5 implanted therein, and a movable contact 6;
A current-carrying tube 14 integrally coupled with a buffer cylinder 11 that compresses arc-extinguishing gas between a stationary piston 12 and a current collector 15 and a bushing conductor 3 working together with the movable contact 6 and a fixed piston 12.
It flows out from the other main terminal 3a via b(!l:.

When the current is cut off, the insulation operation iron 6 is pulled in the X direction in the figure by a drive mechanism (not shown), and the buffer cylinder 11 is driven to the right via the current carrying tube 14 connected to the insulation operation iron 16. buffer room 1
3 gas is compressed. This compressed gas surrounds the movable contact 6 and is delivered to the fixed contact 5 by an insulating nozzle 7 attached to the end face of the buffer cylinder 11 on the fixed contact side.
The insulating nozzle 7 leads to the separation gap between the movable contact 6 and the movable contact 6.
The goarc is blocked by the cooling effect when it is ejected adiabatically from the throat part (7°a in Figure 2) of the goarc. In this example, the insulating nozzle 7 is rigidly attached to the buffer cylinder 11 using a nozzle holder 8. Second
The figure shows an enlarged view of the vicinity of the fixed and movable solid contacts. In the figure, the upper half shows the closed state and the lower half shows the closed state.

Figure 3 shows the situation near the arc when it is cut.

In this case, the arc 21 is thick, so the gas J9 is blocked by the arc 21 and is freely blown onto the current-carrying tube 14.
Most of the gas is exposed to the arc and becomes the expanded high-temperature gas 20 of the body fk, and flows back into the buffer chamber 13.

Therefore, as shown in FIG. 4, the pressure rise in the buffer chamber 13, that is, the buffer pressure, increases as shown by ΔP2 when the large current is interrupted, compared to Jl during no-load when the large current is not interrupted.

By the way, large current interruption in this type of buffer type gas circuit breaker occurs when the tip of the fixed contact 5 escapes from the throat section 7a of the insulating nozzle 7, and the high pressure gas on the upstream side of the throat section exits from the outlet of the throat section. This is done by the cooling effect when it expands adiabatically in the direction. The arc extinguishing power of this male gas increases as the pressure in the C exhaust chamber 13 increases. Therefore, the fixed contact 5 is connected to the throat portion 7a of the insulating nozzle 7.
Until it escapes, the high temperature gas exposed to the arc20
is accumulated in the buffer chamber 13 as much as possible to increase the pressure,
As soon as the fixed contact 5 escapes from the throat part, the buffer chamber 1
A buffer type gas circuit breaker with excellent arc-extinguishing property can be obtained by explosively ejecting the gas with increased pressure inside the valve from the throat portion.

From this point, the distance indicated by Lo in Fig. 2 does not cause stagnation of the gas flow on the upstream side of the throat, and as long as the total passage time does not exceed the specified value, the larger the distance, the more high-temperature gas will be generated. The amount is also large, which is preferable.

On the other hand, FIG. 5 shows the process of interrupting a so-called small current such as a charging current of an unloaded power transmission line. In this case shut off °
t@: Since the current is small, from tens to hundreds of amperes, the arc 21 is extinguished immediately after the fixed contact 5 and the movable contact 6 are separated. Now, let ta be the time from the opening of the solid contact until the arc is extinguished, that is, the arc time, and let t be the time from the moment the arc is extinguished, then at the point when t becomes equal to 0.5 cycles of the commercial frequency, , there is a sixth
As shown in the figure, for example, in a system where the neutral point is not grounded, a high voltage of 2.5 E (E is the phase voltage) is applied. Therefore, not only is there a loose gear between the surface contacts, but also keeping them away from the insulating nozzle 7 is an important point for improving the small current connection performance. For this purpose, it is necessary to reduce Lo shown on the right side of FIG.

In this way, there are two conflicting requirements for large current interruption and small current interruption, whereas in the past, for example, Lo was kept large for large current interruption (electrostatic seal)" (9 in Figure 1) Measures have been taken to reduce the electric field near the tip of the fixed contact, or to increase the opening speed by increasing the operating force, but these all result in a significant price increase. As a result, effective countermeasures were desired.

[Purpose of the invention]

In view of the above, this invention is an inexpensive buffer type with improved interrupting performance in all ranges from large currents to small currents by simply modifying conventional components and adding simple parts. The purpose is to provide a gas cutoff device.

[Key points of the invention]

This invention forms a buffer chamber between a fixed contact, a movable contact, and a fixed piston in a container filled with an arc-extinguishing gas, and also operates together with the movable contact to gas in the buffer chamber. a buffer cylinder that surrounds the movable contact and is attached to the fixed contact side end face of the buffer cylinder to guide the compressed gas to the gap between the fixed and movable contacts and to compress the guided gas. In a buffer type circuit breaker equipped with an insulating nozzle 7 having a throat portion from which a The distance between the throat portion and the movable contactor is changed by the gas pressure in the buffer chamber, and excellent breaking performance is always achieved depending on the magnitude of the breaking current.

[Example of departure J]

An embodiment of the present invention is shown in Figure 7.8.9. As can be seen from the figure, a plurality of springs 23 are arranged at equal intervals on the circumference between the nozzle holder 8 and the flange 7b on the end face of the insulating nozzle, and each spring 23 is installed in the nozzle holder 8. Further, the position is held by a guide pin 18 so as not to shift laterally. Also, the nozzle holder 8 has bolt 1
7, it is fixed to the buffer cylinder 11.

Here, the strength of the spring 23 is the maximum value of the buffer pressure in the buffer chamber 13 when there is no negative pressure (APIQ) shown in FIG. 4 (△)? The setting is such that compression begins when I M is exceeded, and the distance L1 between the throat part of the insulating nozzle and the movable absorber is such that the minimum necessary gas flow is obtained in contrast to the small current interruption. The distance is set shorter than Lo of the conventional circuit breaker shown in Figure @2.

FIG. 8 shows how a small current is interrupted by such a configuration. In this case, since the breaking current is small, the pressure rise in the buffer chamber 13 is the same as in the case of no load, so the insulating nozzle 7 remains pressed against the end face of the back cylinder 11 and does not move, resulting in a fixed contact. The child 5 escapes from the throat portion 7a of the insulating nozzle 7 in a short time after leaving by a short separation distance. Therefore, as soon as another 0.5 cycle elapses after the arc time shown in FIG. 6, what happens to the fixed contact 5? It is far away from the three-edge nozzle 7, and penetration failure in the gas gap between the fixed contact 5 and movable contact 6 and creepage failure along the inner surface of the insulating nozzle are unlikely to occur.

On the other hand, when a large current is interrupted, the arc 2 shown in Figure 9
1, the pressure in the buffer chamber 13 becomes ΔP in FIG.
Since it rises beyond IM, the insulating nozzle 7 moves to the left against the spring 23, and the distance between the throat portion 7a of the insulating nozzle 7 and the movable contact 6 is changed from the conventional distance shown in FIG. The distance #L2 is longer than the distance L'o. The arc energy or arc power during unit time is this distance p! t
Since it is approximately proportional to iL2, the temperature of the high-temperature gas exposed to the arc ζ becomes increasingly higher and its volume expands significantly. As a result, the pressure in the buffer chamber 13 increases more and more, and as soon as the fixed contact 5 escapes from the throat portion 7a of the insulating nozzle 7, the arc is extinguished by the cooling effect due to explosive adiabatic expansion.

As described above, by simply inserting the spring 23 between the nozzle holder 8 and the flange 7b of the insulating nozzle 7, the gap between the throat portion 7a of the insulating nozzle 7 and the movable contact 6 can be adjusted depending on the current value to be interrupted. Since the distance can be changed, it is possible to obtain a circuit breaker with improved interrupting performance over all ranges from large currents to small currents.

In the above embodiment, the flange 7 of the insulating nozzle 7
Although b is shown as being formed from the same material as the nozzle body, this flange could also be formed from a metallic material that is affixed or fastened to the nozzle body. Moreover, a ring-shaped rubber surrounding the insulating nozzle can be used as a suspension instead of the spring 23, and the first
It is also possible to provide the spring 23 inside the buffer cylinder 11 as in another embodiment shown in the θ diagram.
C. In short, is the distance hi between the throat part of the insulating nozzle and the movable contact the gas pressure in the pack chamber? If it is installed so as to be variable depending on this, it becomes possible to improve the interrupting performance over the entire range of interrupting current.

〔Effect of the invention〕

As described above, according to the present invention, the components of conventional circuit breakers are simply modified and elastic members are added so that the distance between the throat portion of the insulating nozzle and the movable contact changes depending on the bumper pressure. Just by inserting it, it is possible to improve the interrupting performance in all ranges from large current to small current, so it has a great economical advantage.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an example of a conventional buffer type gas circuit breaker, Fig. 2 is an enlarged view of the vicinity of the contact in Fig. 1, and Fig. 3 is an enlarged view of the vicinity of the contact in Fig. 1.
Figure 4 shows the gas flow near the arc when a large current is interrupted.
The figure shows the change in buffer pressure over time during no-load operation of the circuit breaker and when breaking a large current. Figure 5 is a diagram explaining the location of insulation breakdown when breaking a small current. Figure 6 shows the change in the buffer pressure when breaking a small current. Fixed. Diagram showing the time change of the voltage applied between the movable direct contactors, No. 7
The figure shows an embodiment based on the present invention, FIG. 8 is a diagram explaining the state of the interrupting part when a small current is interrupted by the structure shown in the embodiment of FIG. 7, and FIG. FIG. 10, which is a diagram for explaining the state of the interrupting section when interrupting the current, is a diagram showing another embodiment based on the present invention. 1: Container, 5: Fixed contact, 6: Movable contact, 7: Absolute R
Nozzle, 11: buffer cylinder, 12: fixed piston, 13: buffer chamber, 23: spout b Fig. 5 Fig. 6.

Claims (1)

[Claims] 1) A buffer chamber is formed between a fixed contact, a movable contact, and a fixed piston in a container filled with arc-extinguishing gas, and the buffer chamber works together with the movable contact to compress the gas in the buffer chamber. A buffer cylinder, which surrounds the movable contact and is attached to the fixed contact side end face of the buffer cylinder, guides the compressed gas to the separation gap of the fixed and movable solid contact, and the guided gas blows out. In the buffer type gas circuit breaker, the insulating nozzle has a throat portion, and the insulating nozzle is connected to the fixed contact iii! of the buffer cylinder by an elastic member. 1. A buffer type gas circuit breaker, characterized in that the buffer type gas circuit breaker is attached to an end face by being pressed, and the distance # between the throat portion of the insulating nozzle and the movable contact ♂ is made variable depending on the gas pressure in the buffer chamber.