JPS62268026A - Fine gap current limiting 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 [Field of Industrial Application] The present invention relates to a slit current limiting type circuit breaker that limits the short circuit current and extinguishes the arc when a short circuit accident occurs in a power system.

[Conventional technology]

As this type of slit@flow type device, for example, the patent application No. 58
There is one proposed in No.-189569.

Figure 3 shows this Iz-defined slit current-limiting type 2i? f. That is, FIG. 3 is a top view thereof.

FIG. 2B is a side sectional view taken along the line A-A in the same figure, and FIG. C1 is a front sectional view taken along the line fBL B-B in the same figure.

In the slit current limiting device, a fixed electrode 1 and a movable electrode 2
Arc runner electrodes 3 and 4 are provided in parallel above each other. These arc runner electrodes 3 and 4 are provided with protrusions 3a and 4a, respectively. In addition, these protrusions 3a and 4a create a wide slit g1 near the fixed electrode 1 and movable electrode 2, respectively, and create a narrow slit g2 toward the tips of the arc runner electrodes 3 and 4. Molded. Furthermore, an arc extinguishing plate 5 is arranged with respect to the arc runner electrodes 3 and 4 so as to sandwich these protrusions 3a and 4a from both sides.

As a result, the gap formed between the arc extinguishing plate 5 and the protrusions 3a and 4a is a wide gap g1 near the base ends of the arc runner electrodes 3 and 4, and a gap g1 near the tips of the arc runner electrodes 3 and 4. There is a narrow gap g2. A discharge port 6 is provided at the opening of the narrow gap g2.

In addition, the reference numeral 7 in FIG. 3 indicates a current collector, and the reference numeral 8 indicates a current collector housing.

In a slit current limiting device having such a structure, except for the discharge port 6, there are a fixed electrode 1, a movable electrode 2. By covering the arc runner electrode 3.4 and the arc extinguishing plate 5 with an insulating container 9, the space between the fixed electrode 1 and the movable electrode 22 and the above-mentioned narrow space function as a pressurization chamber 10. . When the arc is extinguished, high-pressure gas is discharged from the pressurization chamber 10 to the atmosphere through the discharge port 6. On the other hand, the pressurization chamber 10 has arcs A, ~A
, separated from the atmosphere by .

In addition, there is a movable pi on the movable side! 2 and the arc runner electrode 4 are electrically connected by a current collector 7 and a current collector housing 8. This current collector 7 is connected to the pressurizing chamber 10 from the atmosphere.
It also has the function of sealing.

The slit current limiting device operates as follows.

The fixed electrode 1 and the movable electrode 2 are in a normal pre-illll contact state. At this time, when an overcurrent occurs, the movable electrode 2 is opened by an external mechanism (not shown), and as shown in FIG.
As shown at b+, an arc A1 is generated between the fixed electrode 1 and the movable electrode 2. This arc A is elongated into an arc shape with the opening operation of the movable electrode 2, and finally moves to the protrusions 3a, 4a of the arc runner electrode 3.4.
It becomes arc A2, and continues to rise further to become arc A.

The current path at this time is fixed electrode 1 - arc runner electrode 3 - arc A, +→arc runner electrode 4 - movable electrode 2. That is, the current path has a convex shape, and the magnetic field generated by the current flowing through the arc runner electrodes 3 and 4 acts in a direction perpendicular to the arc current. Therefore, according to Fleming's left hand rule, arc A is the third
(Fig. 2) attempts to shift upward.

In addition to the magnetic field generated by the current flowing through the arc runner electrodes 3 and 4, the magnetic field acting on the arc A is generated by a separately provided external coil so as to cross the arc A at right angles. It is also possible to use a magnetic field that is

This electromagnetic force causes the arc A to migrate through the gap space towards the narrower gap. At this time, the gas inside the pressurizing chamber 10 is heated by the arc heat of about 5000 to toooo degrees Celsius from the time the arc is generated until the arc runs through the slit. Since the pressurizing chamber 10 has a structure sealed against the atmosphere, the internal pressure of the pressurizing chamber 10 increases.

Also, due to the contact between the arc A and the arc extinguishing plate 5,
A part of the wall of the arc-extinguishing plate 5 is melted and vaporized. These vaporized and thermally dissociated molecules have the effect of further increasing the internal pressure of the pressurizing chamber 10.

Then, as arc A moves to the narrower side of the slit,
The diameter of arc A is equal to the slot gear knob length. When the arc A3 moves to a gap narrower than the slit gap length, the arc A3 between the pressurization chamber 10 and the discharge port 9 is
A occlusion phenomenon occurs.

Due to this blockage by the arc A, the pressurizing chamber 10 is completely sealed, and the internal pressure of the pressurizing chamber 10 further increases. As a result of this pressure increase, arc A attempts to penetrate into a narrower slit. At this time, as in the conventional case, the arc extinguishing plate 5 due to arc heat
Due to the vaporization of the wall and the thermal work that removes latent heat, a back pressure is created in the slit space of the discharge port 6 regarding the end A3. However, since the pressure in the rising chamber 10 is sufficiently increased between the time of firing and the time of closure, this back pressure can be overcome.

After the pressurization chamber 10 is closed, the arc moves toward an even narrower slit due to the force of [internal pressure of the pressurization chamber 10 - back pressure] and electromagnetic force. Then, as the current increases, the current reaches zero, and the arc A is extinguished and disappears from the slit space. At this time, the high pressure gas stored in the pressurization chamber lO At the same time as A1 disappears, it is discharged through the discharge port 6.

[Problem that the invention seeks to solve]

However, in the conventional method, since a short circuit current flows, the arc A1 generated when the movable electrode 2 separates from the fixed electrode 3 reaches the protrusions 3a, 4a of the arc runner electrode 3.4. The adhesion time to the fixed and movable electrode 1.2 becomes longer. the result,
This delays the time it takes for the arc to be inserted into the slit arc extinguishing chamber, increasing the arc voltage in the slit and requiring a long time for the arc to be extinguished. Also, arc AI7'l<
Because the time spent stuck to electrodes 1 and 2 is long, electrodes 1 and 2
The disadvantage was that the damage to the contacts was large.

Therefore, the present invention was devised to solve such problems, and is a slit current limiting method that promotes the transfer of the arc to the arc runner electrode and makes it possible to extinguish the arc in a short time. The purpose is to provide a type circuit breaker.

Means for Solving Problem C] In order to achieve the purpose, the slit current limiting circuit breaker of the present invention has the following:
In a slit current limiting type circuit breaker, arc running runner electrodes are arranged in parallel and facing each other above a pair of fixed electrodes and a movable electrode, and the runner electrodes are sandwiched between arc-extinguishing plates. The contact portion of the movable electrode is surrounded by an insulating hollow body extending along the electrode opening direction, and an elongated gas outlet is formed in the portion of the hollow body where the runner electrode is located.

The hollow body may be made of nitride ceramics and/or composite ceramics thereof. However, without being restricted to this, when the slit current limiting type circuit breaker is of the SF or gas-filled type, it is also possible to use a hollow body made of a thermosetting organic material.

In addition, the gap between the hollow body and the movable electrode is filled with a zero sealing material.
By interposing the ring, gas injection can be limited to only the locations corresponding to the runner electrodes.

[Effect]

That is, an insulating hollow body is provided close to the separable fixed electrode and the movable electrode so as to surround these electrodes. The gas inside this insulating hollow body is heated and expanded by the arc heat generated by the short circuit current. Also,
When this insulating hollow body is made of nitride-based ceramics and/or composite ceramics thereof, the inner surface layer of the hollow body is decomposed by the arc and gas is generated. As a result, the gas inside the hollow body becomes high pressure, and this high pressure gas is ejected through the ejection port toward the arc located between the fixed electrode and the movable electrode. As a result, the arc is blown up and its transfer to the arc runner electrode is promoted. Therefore, the time for the arc to stick to the fixed electrode and the movable electrode is shortened, making it possible to quickly extinguish the arc.

〔Example〕

Hereinafter, the features of the present invention will be specifically explained with reference to Examples.

FIG. 1 shows a side sectional view of the slit current limiting type circuit breaker in this embodiment, and FIG. 2 is a sectional view taken along line CC in FIG. In these figures, parts corresponding to those in FIG. 3 are designated by the same reference numerals, and their explanations will be omitted.

In normal times, the fixed electrode 1 and the movable electrode 2 are in contact. Then, when a short circuit current flows through the circuit, the movable electrode 2 is dissociated by a drive device (not shown), and the arc A
, occurs.

Here, the fixed electrode 1 and the movable electrode 2 have a hollow space in their axial direction. Only the protrusions 3a and 4a of the arc runner electrodes 3 and 4 are surrounded by an insulating hollow body 11. This hollow body 11 is made of, for example, silicon nitride-based ceramics, and is provided with an elongated ejection port 12 . Furthermore, an O-ring 13 is interposed between the hollow body II and the movable electrode 2.

As a result, the inner surface of the insulating hollow body 11 is exposed to the arc A
Decomposes on contact with 1. At this time, if the hollow body 11 is made of silicon nitride ceramics, the sublimation and decomposition temperature of silicon nitride is about 1900° C., so nitrogen gas is generated by the arc A1. Also, the inside of the hollow body 11 is arc A
Since it is heated by I, the gas inside it thermally expands. In this way, the internal pressure of the hollow body 11 rises rapidly.

The high pressure gas in this hollow body 11 is directed from the jet nozzle 12 in the direction F.
It is ejected along. This ejected gas flow applies an upward force along the gas ejecting direction F to the arc A1. As a result, the arc A becomes arcuate, and its transition to the arc runner electrodes 3 and 4 is promoted. Then, the arc voltage rises rapidly and arc A is shortened.

Note that the insulating hollow body 11 can also be made of a thermosetting organic material when the slit current limiting type circuit breaker is used in SF or gas.

〔Effect of the invention〕

As explained above, in the slit current limiting circuit breaker of the present invention, the gas ejected from the insulating hollow body
The arc is quickly transferred to the runner electrode. the result,
Since the time for the arc to stick to the fixed electrode and the movable electrode is shortened, damage to the contact portions of the fixed electrode and the movable electrode due to the sticking of the arc is suppressed. In addition, rapid transfer of the arc to the runner electrode is also effective in shortening the interruption time. In this way, according to the present invention, a high-performance, highly reliable slit current-limiting circuit breaker can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view, not showing, of a slit current limiting type circuit breaker according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line C--X in FIG. 1. Also,
FIG. 3 shows a conventional slit current limiting type circuit breaker.

Claims (1)

[Claims] 1. A slit current limiting type in which runner electrodes for arc travel are arranged in parallel and facing each other above a pair of fixed electrodes and a movable electrode, and the runner electrodes are sandwiched between arc extinguishing plates. In the circuit breaker, a contact portion of the fixed electrode and the movable electrode is surrounded by an insulating hollow body extending along the electrode opening direction, and an elongated gas outlet is formed in a portion of the hollow body where the runner electrode is located. A slit current limiting circuit breaker featuring: 2. A slit current limiting type circuit breaker, wherein the hollow body according to claim 1 is made of nitride ceramics and/or composite ceramics thereof. 3. A slit current-limiting circuit breaker, characterized in that a sealing O-ring is interposed in the gap between the hollow body and the movable electrode according to claim 1.