JPH0682531B2 - DC circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a DC circuit breaker.

[Conventional technology]

A conventional reverse current insertion type DC current limiting circuit breaker is disclosed in
As described in Japanese Patent Publication No. 54-149873, it was basically as shown in FIG. That is, as shown in the figure, the DC circuit breaker includes a circuit breaker 2 connected in series to the DC main line 1, a commutation capacitor 3, a reactor 4 and a thyristor switch 5 connected in parallel to the circuit breaker 2. It is composed of a series connection body. When performing the shutoff operation, an opening command is given to the shutoff unit 2, the thyristor switch 5 is ignited after the shutoff unit 2 is opened, and the discharge current from the commutation capacitor 3 is applied to the shutoff unit 2. , The current passing through the breaking portion 2 reaches the current zero point, the breaking portion 2 is extinguished, and the main line current is commutated to the commutation capacitor 3,
The current limit is completed.

[Problems to be solved by the invention]

Since the reverse current insertion type DC circuit breaker cuts off the current before the main line current rises in the event of an accident, the breaker is opened immediately after a short circuit occurs, and the discharge circuit of the commutation capacitor is synchronized with the opening. Need to be formed. However, since the thyristor switch is used for forming the discharge circuit of the commutation capacitor in the above-mentioned conventional technique, it is difficult to synchronize the opening of the mechanically operating breaker and the thyristor switch. It must be dealt with by delaying the arc for a predetermined amount of time. Therefore, there is a problem that the current limiting value of the main circuit current increases and the capacity of the commutation capacitor increases more than necessary. In addition, in a bidirectional circuit breaker that cuts off current in both forward and reverse directions, it is necessary to continuously discharge the discharge current of the commutation capacitor for one cycle or more to reach the current zero point. In the case of a thyristor switch, a half cycle is required. Since it automatically shuts off with a bidirectional circuit breaker, it cannot be applied. In addition, the thyristor switch has a problem that it cannot be used continuously because it has a small withstand current.

The present invention has been made in view of the above points, and reliably synchronizes with the opening of the interruption portion, does not interrupt the discharge circuit until the commutation is completed, and makes it possible to prevent re-arcing between the main electrodes. It is intended to provide a DC breaker.

[Means for solving problems]

The above-mentioned object is to dispose the interrupting section on the main fixed electrode provided on the DC main line and the main movable electrode facing the main fixed electrode, and to freely separate the main movable electrode and the main movable electrode inside the main electrodes via the main electrode and the gear gap. It is formed by a vacuum valve composed of auxiliary fixed electrodes arranged coaxially with each other, and a series connection body of a commutation capacitor and a reactor is connected between the main fixed electrode and the auxiliary fixed electrode to separate the main electrodes. Induced arc between the main electrode and the auxiliary fixed electrode by the arc between the main electrodes generated by
This is achieved by discharging the commutation capacitor.

[Action]

The switch operation is performed by the induction firing by the arc between the main electrodes generated between the main electrodes of the interruption part, so that it is surely synchronized with almost no time delay and the arc between the main electrodes is kept between the main electrodes until the commutation is completed. Since it continues, the switch side will not extinguish the arc. Further, since the auxiliary fixed electrode is arranged coaxially inside the main electrode, after the discharge of the commutation capacitor, the arc between the auxiliary fixed electrode and the main movable electrode is the magnetic field and arc created by the current flowing through the auxiliary fixed electrode. Due to the electromagnetic action, the arcs move away from the arc between the main electrodes, and the re-arc between the main electrodes is prevented. Further, when the unloaded line is opened, the arc between main electrodes does not occur between the main electrodes, so that induction arc does not occur and unnecessary switching operation does not occur.

〔Example〕

Hereinafter, the present invention will be described based on the illustrated embodiments. 1 to 3 show an embodiment of the present invention.
Since the same parts as those of the prior art are designated by the same reference numerals, the description thereof will be omitted. In this embodiment, the cutoff portion 2a is arranged to face the main fixed electrode 6 provided on the DC main line 1 and the main fixed electrode 6,
And a vacuum valve composed of a main movable electrode 7 which can be freely contacted and separated, and an auxiliary fixed electrode 8 which is coaxially arranged inside the main electrodes 6 and 7 via the main electrodes 6 and 7, and A series connection body of a commutation capacitor 3 and a reactor 4 is connected between the main fixed electrode 6 and the auxiliary fixed electrode 8, and the main electrodes 6 and 7 due to the arc 9 between the main electrodes generated when the main electrodes 6 and 7 are separated from each other. The commutation capacitor 3 is discharged by induction firing between the 7 and the auxiliary fixed electrode 8. By doing so, it surely synchronizes with the opening of the breaking portion 2a, does not cut off the discharge circuit until the commutation is completed, and prevents the re-arcing between the main electrodes 6 and 7. It is possible to obtain a DC circuit breaker that is reliably synchronized with the opening of the breaking unit 2a, does not block the discharge circuit until the commutation is completed, and is capable of preventing re-arcing between the main electrodes 6 and 7.

That is, the blocking section 2a is composed of a vacuum container 13 formed of main electrodes 6 and 7, auxiliary fixed electrodes 8, insulating cylinders 10 and 11, bellows 12 and the like, and the main fixed electrode 6 and the main movable electrode 7 are DC main lines. Connected to 1. In the closed state shown in FIG. 1, the main line current flows from the main movable electrode 7 to the main fixed electrode 6 as shown by the arrow 14 in the figure.
The commutation capacitor 3 which has been charged in the polarity direction shown in the figure is insulated by the gap between the main fixed electrode 6 and the auxiliary fixed electrode 8.

When the cutoff command is given, the main movable electrode 7 is driven leftward in the drawing by the operating device (not shown), and the main fixed electrode 6 and the main movable electrode 7 are opened as shown in FIG. Release,
An arc 9 between the main electrodes is generated between both electrodes 6 and 7. A commutation capacitor 3 is provided between the main electrode arc 9 and the auxiliary fixed electrode 8.
Is applied to the gear with the auxiliary fixed electrode 8 to induce arcing and generate an arc 15 to form a capacitor discharging circuit shown by an arrow 16 in the figure.

The arc 15 increases and the arc 9 between the main electrodes decreases due to the rising of the discharge current of the commutation capacitor 3, and when the arc 9 between the main electrodes reaches the current zero point, it is between the main fixed electrode 6 and the main movable electrode 7. Is extinguished, and all the main line current is commutated to the commutation capacitor 3, and the current path becomes an arrow 17 as shown in FIG. The electromagnetic force generated by the magnetic field generated by the electric current shown by the arrow 17 flowing in the auxiliary fixed electrode 8 and the arc 15 is indicated by the arrow 18 in the figure.
Since the arc 15 moves away from the arc between the main electrodes, it does not re-ignite between the main electrodes 6 and 7 after extinguishing the arc, as shown by the arrow 17 after commutation. The current gradually decreases, and when the current reaches the zero point, the arc 15 is also extinguished, and the breaking operation is completed.

As described above, according to this embodiment, since the discharge circuit of the commutation capacitor is formed by the induction firing by the inter-main electrode arc generated between the main electrodes, the discharge is surely synchronized with the opening of the main electrodes with almost no time delay. The current limiting value of the main line current can be suppressed to a small value, and the required capacity of the commutation capacitor can be reduced. Further, since the arc between the main electrodes between the main electrodes continues until the commutation is completed, the discharge circuit of the commutation capacitor is maintained, and it can be applied as a bidirectional circuit breaker. Further, when the unloaded line is opened, the arc between the main electrodes does not occur between the main electrodes, so that induction arc does not occur, unnecessary switching operation does not occur, and damage to the electrodes can be reduced.

〔The invention's effect〕

As described above, the present invention surely synchronizes with the opening of the breaking portion, does not cut off the discharge circuit until commutation is completed, and prevents re-ignition between the main electrodes, thereby preventing the breaking of the breaking portion. It is possible to obtain a DC circuit breaker that is reliably synchronized with the opening, does not block the discharge circuit until commutation is completed, and can prevent re-arcing between the main electrodes.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a closed state of a breaking portion of an embodiment of a DC circuit breaker of the present invention, FIG. 2 is a circuit diagram showing a state immediately after opening of the breaking portion of the embodiment, and FIG. Is a circuit diagram showing a state after commutation of the circuit breaker of one embodiment, and FIG. 4 is a circuit diagram of a conventional DC circuit breaker. 1 ... DC main line, 2a ... Breaking part, 3 ... Commutation capacitor, 4 ... Reactor, 6 ... Main fixed electrode, 7 ... Main movable electrode, 8 ... Auxiliary fixed electrode, 9 ... Main Arc between electrodes.

Claims (1)

[Claims] 1. A cutoff portion provided on a DC main line and a series connection body of a commutation capacitor and a reactor connected to the cutoff portion, wherein the cutoff portion is cut off from the commutation capacitor when the cutoff portion is opened. In a DC breaker of the reverse current insertion type, in which a discharge current in the direction opposite to the main line current is forced to cut off in a reverse current insertion system, the breaker is a main fixed electrode provided in the DC main line and this main fixed It is formed by a vacuum valve composed of a main movable electrode which is arranged to face the electrode and is freely contactable and separable, and an auxiliary fixed electrode which is coaxially arranged inside these main electrodes via these main electrodes and a gap. The main electrode and the auxiliary fixed electrode are formed by connecting a series connection body of the commutation capacitor and the reactor between the main fixed electrode and the auxiliary fixed electrode, and by an arc between the main electrodes generated when the main electrodes are separated from each other. In the induction onset arc, DC breaker being characterized in that so as to discharge the commutation capacitor.