JPH07122164A - Puffer type gas-blast circuit breaker - Google Patents

Abstract

PURPOSE:To improve interrupting performance without carrying a capacitor current nor increasing a puffer cylinder capacity in the state where the contact of an arc-extinguishing chamber is opened. CONSTITUTION:When interrupting operation is started, a short-circuit current is commutated to arc contacts 1, 2 from current-carrying contacts 13, 14 to generate an arc 15. The generated magnetic flux acts on a magnetic body 12 on the inside of a fixed electrode. The magnetic body 12 is saturated in a large current period. When the current is reduced to the saturating point of the magnetic body, the state of zero current is held by a large inductance. The inclination of the current zero point is moderated by this action, and the rise ratio of transient recovery voltage after the failure interruption of a near distance line determined by the inclination of the current zero point and the serge impedance of the system can be lowered. The inside of the magnetic body 12 is protected by a heat resisting member 11, and its magnetic characteristic is never changed even when it is directly exposed to the arc. According to such a constitution, a large failure current can be interrupted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a puffer type gas circuit breaker,
In particular, the present invention relates to a puffer type gas circuit breaker that suppresses surge after interruption.

[0002]

2. Description of the Related Art In a gas circuit breaker, when a current interruption operation is performed, an arc is generated between a fixed electrode and a movable electrode. In order to extinguish this arc, in a conventional gas circuit breaker, a gas flow of SF6 gas was blown to the arc from an insulating nozzle. After the current is cut off, the recovery voltage of the power source and the transient recovery voltage determined by the system configuration, short circuit, or ground fault position appear between the circuit breaker contacts.

By the way, in short-distance fault current interruption, a very rapid rising transient recovery voltage determined by the product of the slope of the current at the current zero point during current interruption and the surge impedance of the system occurs as the interruption current increases. This transient recovery voltage increase rate greatly affects the breaking performance of the circuit breaker. In order to cut off, it is necessary to increase the volume of the puffer cylinder or increase the contact opening speed to increase the pressure rise in the puffer cylinder, so the device becomes larger. It is important to suppress the transient recovery voltage rise rate in order to shut down the equipment without making it bulky.

In order to moderate the transient recovery voltage increase rate, in the conventional gas circuit breaker, a capacitor is installed between the poles of the arc extinguishing chamber to improve the performance of the circuit breaker without increasing the puffer cylinder volume. I was letting it.

However, in such a structure, even if the contactor of the circuit breaker is opened, the capacitor current flows through the capacitor side, and the circuit cannot be completely cut off even though the contactor is completely open. It was

[0006]

As described above, it is important to connect the capacitor in parallel with the arc-extinguishing chamber in order to improve the short-circuit line fault current interruption performance.
Even if the contactor was completely opened by disconnecting it from the system, the capacitor current flowed to the capacitor side and it could not be completely disconnected.

Further, it is expected that the capacity of the gas circuit breaker will be further increased in the future, but in such a case, the capacity of the capacitor connected between the arc-extinguishing chamber poles also increases, and the capacitor current tends to increase more and more. . However, if the capacitor is not installed, it is necessary to increase the volume of the puffer cylinder or increase the opening speed.

The present invention has been made in view of the above problems, and an object thereof is to prevent the capacitor current from flowing and to increase the volume of the puffer cylinder in a state where the contact of the arc extinguishing chamber is opened. To provide a puffer type gas circuit breaker with improved breaking performance.

[0009]

To achieve the above object, the first aspect of the present invention comprises a fixed arc contactor and a movable arc contactor which can be contacted and separated from each other in a container filled with an arc-extinguishing gas. , The arc extinguishing gas is compressed by compressing the puffer chamber composed of the puffer piston and the puffer cylinder provided on the movable part side, and is guided to the nozzle part, which is generated between the fixed movable arc contact and the movable arc contact. In a puffer-type gas circuit breaker having an arc-extinguishing chamber for extinguishing the arc by blowing it, heat resistance inside the fixed energizing contact provided coaxially with the fixed arc contact and having an inner diameter larger than the outer diameter of the fixed arc electrode It is characterized in that a magnetic material surrounded by a magnetic member is arranged. A second aspect of the present invention is characterized in that a magnetic body surrounded by a heat resistant member is arranged so as to be in contact with the inside of the fixed energizing contact. Further, a third aspect of the present invention is characterized in that a magnetic body surrounded by a heat resistant member is arranged around the fixed arc contact.

[0010]

According to the puffer type gas circuit breaker of the present invention, the current zero point is to be maintained until the saturation, which is determined by the saturation magnetic flux density of the magnetic material, is reached after interrupting the fault current. As a result, the slope of the current in the vicinity of the current zero becomes equivalently gentle, and the rate of increase in the transient recovery voltage correspondingly decreases, so that a large fault current can be interrupted.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the present invention. In the figure, the arc-extinguishing chamber of the gas circuit breaker according to the present embodiment includes a fixed arc contactor 1 and a movable arc contactor 2, which are freely contactable and separable when interrupting a current, and a movable side on which the movable arc contactor 2 is attached. A puffer chamber 5 composed of a puffer cylinder 3 fixed to an operating rod 7 of the above, and a puffer piston 4 supported and fixed by the puffer cylinder 3 and a movable side fixed portion.
By compressing the puffer chamber 5, SF6 gas is blown to the arc between the fixed arc contact 1 and the movable arc contact 2 through the nozzle 6 fixed to the puffer cylinder 3 by the movable energizing contact 13 to extinguish the arc. The operating rod 7 is mechanically connected to a driving device (not shown) via an insulating rod.

The fixed arc contactor 1 is arranged on the central axis of the fixed side electrode 9 supported by the insulating cylinder 8 fixed to the movable side fixed portion, and is supported by the rib 10 from the fixed side electrode 9. There is. Fixed side electrode 9 and movable current contact 1
A fixed current-carrying contactor 14 that can be brought into contact with and separated from the device 3 is arranged.

Further, a magnetic substance 12 made of a ferromagnetic material such as an amorphous alloy, which is concentrically surrounded by a heat resistant member 11, is fixed to the inside of the fixed electrode 9. The inner diameter of the magnetic body 12 is configured to be larger than the maximum outer diameter of the movable energizing contact 13.

Next, the operation of this embodiment will be described with reference to FIGS. In the closed state of FIG. 1, a commercial frequency current flows. For example, from the AC magnetization curve of the amorphous fluoropolymer alloy 2605S-2 shown in FIG.
The magnetization intensity at the saturation point in Hz is calculated to be 22 A / m.
Becomes In the closed state, the commercial current flows through the movable energizing contact 13 and the fixed energizing contact 14, and the magnetic flux generated thereby does not enter the inside of the energizing contact. Therefore, the magnetic material disposed inside the fixed electrode 12 does not work.

When a short-circuit accident occurs and the circuit breaker starts the breaking operation as shown in FIG.
3 and fixed energizing contactor 14 commutate to fixed arc contactor 1 and movable arc contactor 2 to generate arc 15.
The magnetic flux generated by the arc current flowing through the fixed arc contactor 1 is the magnetic body 12 disposed inside the fixed electrode.
Act on. In the large current period, the magnetic substance 12 is saturated because the current is large. When the current decreases to the saturation point of the magnetic substance near the current zero point, the saturation is released and a large inductance is exhibited, so that the state of zero current is maintained. Due to this action, the slope of the current zero becomes equivalently gentle, and the transient recovery voltage rise rate after interruption of the short-distance line failure determined by the slope of the current zero and the surge impedance of the system can be reduced. The magnetic body 12 has its inside protected by the heat-resistant member 11 and its magnetization characteristics do not change even if it is directly exposed to an arc.

As described above, in the puffer type gas circuit breaker of this embodiment, the magnetic body protected by the arc resistant member is arranged inside the fixed electrode side, and the magnetic body is placed inside the conductor to be energized in the closed state. Therefore, there is no linkage due to the applied current. When the breaking operation is started and a current is transferred between the arc contacts in the middle of the breaking operation, the current is linked to the magnetic body, and the effect of the magnetic body appears. In the vicinity of the current zero point, since the current tends to be retained, the current slope becomes gentle and at the same time the transient recovery voltage increase rate becomes moderate, resulting in a sharp transient recovery voltage increase rate after interruption, such as a short-distance line failure. In such shutoff, the effect is exhibited, and shutoff is possible without installing a parallel capacitor for easing the transient recovery voltage rise rate in the arc extinguishing chamber.

FIG. 4 is a cross-sectional view of another embodiment of the present invention. The difference between this embodiment and the above embodiment is that the arrangement of the magnetic body is different and the other construction is the same. The same parts are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 4, in this embodiment, a magnetic body 12a is arranged around the fixed arc contactor 1 and an arc resistant member 11a is provided outside the magnetic body 12a to prevent the magnetic body 12a from being exposed to an arc. I have to. It is obvious that the same effect as the above embodiment can be obtained in this embodiment.

[0018]

As described above, in the puffer type gas circuit breaker according to the present invention, a short-distance line fault current is generated even if the capacitor is not installed in parallel in the arc extinguishing chamber and the puffer cylinder volume is not increased. The transient recovery voltage rise rate can be reduced to enable interruption. Further, when applied to a puffer type gas circuit breaker that does not use a capacitor, it is possible to reduce the volume of the puffer cylinder and it is possible to downsize the puffer type gas circuit breaker.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining the action during the interruption of FIG.

FIG. 3 is a diagram showing characteristics of the magnetic body of FIG.

FIG. 4 is a sectional view of another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed arc contactor, 2 ... Movable arc contactor, 3 ... Puffer cylinder, 4 ... Puffer piston, 5 ... Puffer chamber, 6 ... Nozzle, 7 ... Operation rod, 8 ... Insulation cylinder, 9 ... Fixed side electrode, 10 ... ribs, 11, 11a ... heat-resistant members, 1
2, 12a ... Magnetic material, 13 ... Movable current contactor, 14 ... Fixed current contactor, 15 ... Arc.

Claims (3)

[Claims] 1. A puffer chamber comprising a puffer piston and a puffer cylinder provided on the movable part side, having a fixed arc contactor and a movable arc contactor which can be contacted and separated from each other in a container filled with an arc-extinguishing gas. In a puffer type gas circuit breaker having an arc extinguishing chamber for extinguishing the arc generated by compressing the arc extinguishing gas by compressing it to the nozzle portion and blowing the arc generated between the fixed arc contact and the movable arc contact, A magnetic material is disposed inside a fixed current-carrying contact provided coaxially with the fixed arc contactor, and the circumference thereof is surrounded by a heat-resistant member whose inner diameter is larger than the outer diameter of the fixed arc contactor. Puffer type gas circuit breaker. 2. The puffer-type gas circuit breaker according to claim 1, wherein a magnetic body surrounded by the heat-resistant member is arranged so as to be in contact with the inside of the fixed energizing contact. 3. The puffer-type gas circuit breaker according to claim 1, wherein a magnetic body surrounded by the heat-resistant member is arranged around the fixed arc contactor.