JPH03295121A - Buffer shaped gas-blast circuit 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] 1. Industrial application field” The present invention relates to a buffer type gas circuit breaker.

"Prior Art" Gas circuit breakers are manufactured to shut off accidental N-flow, etc. within a time commensurate with the operating conditions of the system.

After the current interruption is completed, the movable electrodes come to rest with a distance between the electrodes commensurate with the equipment's rated insulation level.

FIG. 3 shows an example of the extinguisher structure of such a gas circuit breaker, in which an insulating gas 7 is filled in a container 6 with a closed structure, and a drive device 15 is connected to the center of the container 6 by an operating rod 8. A connected arc extinguisher 12 is provided.

The arc extinguisher 12 is connected to the buffer cylinder 4. Buffer piston 5. It is composed of a fixed electrode 1 and a movable electrode 2 that can be freely connected and separated, and after extinguishing the generated arc 9 by spraying insulating gas 7 in the buffer cylinder 4 toward the fixed electrode 1 from the insulated nozzle 3, the equipment rating is determined. The movable electrode 2 remains stationary with an electrode open circuit IFIJ commensurate with the insulation level of .

"Problem to be Solved by the Invention" When an accident occurs in a system due to multiple lightning strikes and a lightning surge voltage due to multiple lightning strikes is applied to the system immediately after the fault current is cut off by a gas circuit breaker, the gas A breakdown of the insulation between the circuit breaker electrodes 1 and 2 may cause the fault current to flow again.

Conventionally, when the movable electrode 2 comes to rest, that is, until the compressed gas 7 in the buffer cylinder 4 stops blowing onto the fixed electrode 1, there is an opportunity to cut off the fault current that has flowed again, so-called current zero point. Although the fault current was successfully cut off,
If there is no current zero point, there is a drawback that current interruption will fail.

"Means for Solving the Problems" In view of the drawbacks of the prior art described above, the present invention prolongs the spraying time of compressed gas by increasing the moving distance of the movable electrode.

``Effect'' By extending the spraying time of compressed gas, the chances of interruption are increased to three or more times, making it possible to interrupt the fault current even if multiple lightning strikes are applied immediately after the current interruption.

"Example" Hereinafter, an example of the present invention will be described in detail based on FIGS. 1 and 2. Note that the same numbers are given to parts that are the same as those in the prior art described above, and redundant explanations are omitted.

FIG. 1 shows an embodiment of the present invention, in which the moving distance of the movable electrode 2 is made longer than in the prior art, and the volume of the insulating gas 7 in the buffer cylinder 4 is increased. FIG. 2 shows the movement of the movable electrode 2 and the gas pressure inside the Pantsoff cylinder 4 during current interruption in this embodiment. Normally, the current is interrupted at the current zero point shown by the solid line, but if a lightning surge voltage due to multiple lightning is applied immediately after this current interruption and dielectric breakdown occurs between electrodes 1 and 2, the current shown by the broken line will continue to flow. .

In conventional gas circuit breakers, it is sometimes possible to interrupt the circuit at the current zero point indicated by the broken line, but immediately after this interruption, the lightning surge voltage due to multiple lightning strikes is applied again, causing dielectric breakdown between electrodes 1 and 2. In this case, it becomes impossible to quickly cut off the current at the zero point on the one-dot chain line where the current continues to flow again because the insulating gas in the cylinder 4 is almost completely exhausted. However, in the present invention, as shown in FIG. 2, the insulating gas in the Pantsoff cylinder 4 exists at a certain pressure even at the current zero point indicated by the dashed-dotted line, so the current can be cut off with certainty. be done.

FIG. 4 shows another embodiment of the present invention, in which the gas pressure in the buffer cylinder 7 is kept almost constant when the current is cut off in the embodiment shown in FIG. 1. The gas pressure is adjusted by a spring 8. FIG. 5 shows the movement of the movable electrode 2 and the gas pressure inside the buffer cylinder 4 when the current is cut off in this embodiment. The gas pressure is determined by balancing the energy of the arc and the increase in gas pressure due to the reduction of the buffer cylinder internal volume with the force of the spring so that the gas pressure remains almost constant at a level slightly higher than the gas pressure that can be cut off, and the gas ejection is prevented. Even after the movable electrode 2 has come to rest, the compression is performed by the compression of the cylinder by the force of the spring. As a result, it is possible to obtain the effect that the chances of current interruption are greatly increased compared to the embodiment shown in FIG.

1. Effects of the Invention As described above, by lengthening the ejection time of the high-speed gas flow, it is possible to improve the performance of interrupting fault currents caused by multiple lightning.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a gas circuit breaker which is an embodiment of the present invention, FIG. 2 is a diagram showing movable electrode movement and cylinder pressure change during current interruption according to the embodiment, and FIG. 3 is a diagram showing the prior art. FIG. 4 is a cross-sectional view showing another embodiment of the present invention, and FIG. 5 is a diagram showing the movement of the movable electrode and the change in cylinder pressure during current interruption according to the embodiment. . In the figure, 1 is a fixed electrode 3 is an insulating nozzle 5 is a buffer piston 7 is an insulating gas 9 is an arc

Claims (2)

[Claims] (1) A movable electrode and a fixed electrode that can be freely moved toward and away from each other are arranged in a container filled with an arc-extinguishing insulating gas, and the movable electrode and a buffer cylinder are fixed to one end of an operating rod connected to a drive device, and the buffer cylinder A buffer type in which arc-extinguishing insulating gas is compressed in the buffer cylinder, and this compressed gas is ejected as a high-speed gas flow from an insulating nozzle fixed to the buffer cylinder, and is blown onto the arc generated between the opposing electrodes to extinguish the arc. A gas circuit breaker characterized in that the moving distance of the movable electrode is made much longer than the distance between the electrodes corresponding to the insulation level of the rated voltage, and the ejection time of the high-speed gas flow is lengthened. (2) A gas circuit breaker characterized in that the pressure of the compressed insulating gas in the buffer cylinder is maintained at a substantially constant pressure capable of interrupting current, and the jetting time of the high-speed gas flow is lengthened.