JPS62256331A - Dc 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] [Industrial application field] The present invention relates to a DC circuit breaker.

[Conventional technology]

It is a known fact that DC circuit breakers have been put into practical use for DC power transmission and plasma heating equipment for nuclear fusion (for example, as published in the September 1980 issue of Denki Hyoron).

Conventionally, one set of operating devices for operating a DC circuit breaker has been constructed for each DC circuit breaker (one set for each switching contact).

[Problem that the invention attempts to solve]

In the above conventional technology, it takes a long time from when the opening command is given to the DC circuit breaker until the contacts actually open.Therefore, there is no problem when applying the DC circuit breaker as a load switch, but the fault current When applied to protect circuits that are responsible for breaking, the following problems occur when the contacts open. In other words, when the contact is opened, the Electrical Standards Committee standard $
Standards (DC high-speed circuit breakers for railway substations) (JE
C-152) When calculated using the specified current rush rate of 3 x 106 (A/S), the target value of the estimated short circuit current is already 5
After reaching 0 kA, as a result, the capacitor capacity of the commutation circuit required to create the current zero had to be increased in accordance with the magnitude of the short-circuit current.

In addition, it is not a good idea to increase the operating force just to speed up the opening time, or to use high-speed actuators such as hydraulic actuators or electric≠repulsion actuators, as described below. Comparing the possibility of fault current interruption and the frequency of load switching, the frequency is so high that the load switching is almost instantaneous. Therefore, it is not a good idea to cut off the load current on a daily basis by using the operating force required to cut off the fault current that occurs extremely rarely, and with a light operating force to cut off the load current on a daily basis.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a DC breaker that allows the capacitance of the capacitor to be reduced.

Means for Solving Problem C] The above purpose is to cut off the fault current using a high-speed actuator that operates at high speed, such as a hydraulic actuator or an electromagnetic repulsion coil, and to cut off the load current using a commonly used method. This is achieved by using a normal operating device that operates at low speed, such as an AC 5-cycle circuit breaker, and determining the selection based on the operation of the accident detection relay.

[Effect]

In the case of fault current interruption, the fault detection relay detects the fault,
Gives operation commands to the high-speed actuator. In this case, the closing switch provided in the commutation circuit is closed simultaneously or in synchronization with the opening of the contact. As a result, the contacts are opened during the rising process of the fault current, and the fault current is cut off when a zero point is formed in the fault current due to the high-frequency reverse current applied from the commutation circuit.

In the case of normal load current interruption, the normal operating device is operated by a closing command, and the closing switch of the commutation circuit is closed in synchronization with the opening of the contact. As a result, the load current is cut off when a zero point is formed in the load current due to the high frequency reverse current applied from the commutation circuit.

In this way, when a fault current is cut off, it can be cut off during the rising process, and the capacitor capacity needs to be adjusted to the maximum am value of the fault current (short-circuit current), making it possible to reduce the capacitance of the capacitor. .

〔Example〕

The present invention will be explained below based on the illustrated embodiments. FIG. 1 shows one embodiment of the present invention.6 As shown in the same figure, when DC is cut off, the main circuit IA has a contact 2 provided between the main circuit conductors 1a and lb. ,
A commutation circuit 5A is connected in parallel to the contact 2 of the main circuit IA via a closing switch 3, and in which a 4° capacitor and a reactor 5 are connected in series. When the contact 2 is opened, the closing switch 3 is turned on and the commutation circuit 5A is connected to the contact 2.
A high frequency ffi current is caused to flow through the circuit to interrupt the current.

In this embodiment of the DC breaker configured as described above, contact 2
In addition, there is a high-speed actuator 6 that can open the contact 2 at a higher speed when interrupting a fault current earlier than when interrupting a load current.
and a normal operating device 7 which is capable of opening contact 2 at a lower speed when interrupting load current, slower than when interrupting fault current.
These two operating devices 6 and 7 are selectively operated.

By doing so, the contact 2 is equipped with a high-speed actuator 6 that can open the contact 2 at a high speed earlier than that when the load current is cut off when a fault current is cut off, and a high-speed actuator 6 that can open the contact 2 at a high speed when the load current is cut off. A normal operating device 7 is provided that can open at a low speed, slower than that at the time of interruption, and both operating devices 6 and 7 can be operated selectively to interrupt the fault current in its rising process. This makes it possible to obtain a DC breaker in which the capacitance of the capacitor 4 can be reduced.

That is, during operation, a current flows through the earth circuit conductor 1a, the contact 2 in the vacuum vessel 8, and the main circuit conductor 1b. In this case, the closing switch 3 is open, and the commutation capacitor 4 is constantly charged with the charge I9.

When a fault current flows through the main circuit IA consisting of the main circuit conductor 1a, contact 2, main circuit conductor 1b, etc., an overcurrent relay (not shown) notifies you of the abnormality.

Control device! Send a signal to 10. The control unit [10] determines that there is an accidental current cutoff, and gives an operation command to the high speed actuator 6 and the closing switch 3 to cut off the current.

In this case, the control device controls the synchronization of the opening time of the contact 2 by the high-speed actuator 6 and the time until the current zero point is generated by the commutation circuit 5A formed by the capacitor 4 and the reactor 5, which is formed by the closing of the closing switch 3. 10 to be taken as needed.

In the case of load current interruption, the control device 10 that has received the tripping control command determines that the load current is interruption, and normally operates the operating device 7.
The contact 2〆rjjI pole time by the normal operating device 7 and the time until the current zero point occurs by the commutation circuit 5A are determined by the control device 10 and the normal operating device 7. Synchronization is achieved by setting the operation command time to the closing switch 3 separately.

FIGS. 2(a) and 2(b) show the relationship between the cutoff current and time, with the vertical axis representing current and the horizontal axis representing time. In the figure, B indicates the occurrence of an accident, C indicates one relay time, D indicates opening time, E indicates commutation start, F indicates completion of cutoff, and G indicates cutoff command.

In the case of fault current interruption, as is clear from the same figure (a), when the fault occurs B and the interruption command G is given after relay time C, commutation starts E during the contact opening time, and the fault current The cut-off is completed F while the temperature is rising.

In the case of load current interruption, as is clear from the same figure (b),
Commutation start E is performed during the opening time due to the cutoff command G,
Although the interruption is completed F, the time required for the interruption to be completed F is longer than that of the above-mentioned fault current.

In this way, the interruption can be completed while the fault current is rising, but the
As is clear from the figure, since a vacuum interrupter in which the contact point 2 is housed in the vacuum container 8 is used, the commutation circuit 5A
As the frequency of
can be reduced compared to the case where it is not stored in the vacuum container 8.

In addition, the high-speed actuator 6 drives the lower electrode 2a of the contact 2 in the downward direction of the vacuum interrupter, and the normal actuator 7 drives the upper electrode 2b of the contact 2 in the upward direction. The connection structure with the operating devices 6 and 7 can be simplified.

In this way, according to this embodiment, for fault current interruption, it is necessary to shorten the opening time and strengthen the driving force, and for load interruption, which requires frequent switching performance, the Σ driving force must be reduced in order to extend the service life. By dividing the actuator into one for fault current interruption and one for load current interruption, it is possible to design and manufacture the actuator to suit the respective conditions. Therefore, in fault current interruption, the opening time can be increased without considering durability against frequent operations, and the capacitor capacity can be reduced. In load current interruption, the load on the normal operating device can be reduced without considering accidental current interruption, so its switching life can be extended.

In addition, when an accident current is cut off, two sets of actuators, a high-speed actuator and a normal actuator, are activated.In other words, after the current is interrupted by the high-speed actuator, the operation of the normal actuator, which opened with a time delay, is completed. By resetting the open state maintenance of the high-speed actuator, the main circuit recirculation operation can be performed using only the normal actuator, so there is no need for the high-speed actuator to have a closing capability.
The structure can be simplified.

〔Effect of the invention〕

As described above, the present invention makes it possible to reduce the capacitance of the capacitor, thereby providing a DC breaker that allows the capacitance of the capacitor to be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the DC breaker of the present invention,
Figure 2 Pt (a) and (b) also show the relationship between the breaking current and time in one example, where (a) is the characteristic in the case of fault current interruption, and (b) is the characteristic in the case of load current interruption. It is a diagram. IA...Main circuit, la, lb...Main circuit conductor, 2.
...Contact, 2a...lower electrode, 2b...upper electrode,
3... Closing switch, 4... Capacitor, 5...
reactor. 5A... Commutation circuit, 6... High-speed operation device, 7... Normal operation device, 8... Vacuum container, 9... Charger, 10.
··Control device. shaku

Claims (1)

[Claims] 1. A main circuit having at least one contact provided between main circuit conductors, and a capacitor and a reactor connected in parallel to the contact of the main circuit via a closing switch, and a capacitor and a reactor connected in series. and a commutation circuit connected to the contact, and when the contact is opened, the closing switch is turned on to flow a high frequency current from the commutation circuit to the contact to interrupt the current. There is a high-speed actuator that can open the contacts at a higher speed and faster than when interrupting a load current when a fault current is interrupted, and a high-speed actuator that can open the contacts at a slower speed than when interrupting a fault current when interrupting a load current. 1. A DC circuit breaker characterized in that it is provided with a normal operating device which can be opened and opened by , and the two operating devices are selectively operated. 2. The DC circuit breaker according to claim 1, wherein the high-speed operating device and the normal operating device are both operated when the fault current is interrupted.