JP5144394B2 - DC vacuum interrupter - Google Patents

Description

  The present invention relates to a DC vacuum circuit breaker that opens and closes a current in a DC circuit, and more particularly to a DC vacuum switchgear that can improve noise resistance.

  In the DC vacuum interrupter, in order to interrupt the accident current of the DC circuit, for example, a current zero point is forcibly created by superimposing a current in the opposite direction to the interrupted current, and the vacuum valve can be interrupted (for example, Patent Document 1).

  The configuration of this type of DC vacuum interrupter is shown in FIG. As shown in FIG. 3, the DC vacuum interrupter includes an interrupting unit 1a that interrupts the main circuit current, a commutation unit 1b that injects commutation current into the interrupting unit 1a, and a protection control unit 1c that controls injection of commutation current. It consists of

  The breaker unit 1a is provided with a sub-breaker 2 and a main breaker 3 having vacuum valves connected in series. A current transformer 4 (Hall CT) for detecting a current is connected to the main circuit on the power supply side.

  In the commutation unit 1b, a surge absorbing element 8 is connected in parallel to a reactor 5, a capacitor 6 and a thyristor switch 7 connected in series. These are connected in parallel to the main circuit breaker 3. A charging device 9 and a discharging device 10 are connected to both ends of the capacitor 6.

  The protection control unit 1c includes a current detection circuit 11 that detects a current from the current transformer 4, a state detection circuit 12 that detects the open / close state of the circuit breakers 2 and 3 of the circuit breaker unit 1a, and the circuit breaker unit 1a that is opened manually. An external cutting circuit 13 is provided for making a pole. The outputs of these circuits 11, 12, and 13 are connected to a thyristor operation circuit 14 that operates the thyristor switch 7 and injects a commutation current into the main circuit breaker 3.

  Next, the operation will be described.

  As shown in FIG. 4, when an accident current exceeding a predetermined current value is detected by the current detection circuit 11, a contact opening command is immediately output from the interrupt command circuit (not shown) to the interrupt unit 1a at time t0. When the main circuit breaker 3 of the breaker unit 1a starts to open and reaches a predetermined gap, the state detection circuit 12 detects the open state and outputs a state signal.

  The thyristor operation circuit 14 receives the status signal and immediately outputs a signal for operating the thyristor switch 7 at time t1. Thereby, the commutation current is superimposed on the accident current, and the accident current is interrupted by the main breaker 3 at the current zero point.

On the other hand, during a normal operation, when an opening signal is input to the external disconnect circuit 13 at time t0, an opening instruction is immediately output from an unillustrated interruption command circuit to the interruption unit 1a. Then, similarly to the above, the main circuit breaker 3 starts opening, a state signal is output, and a signal for operating the thyristor switch 7 is output from the thyristor operation circuit 14 at time t1. Thereby, even at the time of normal current, it is interrupted by the main circuit breaker 3 at the current zero point.
JP 2002-93294 A (3rd page, FIG. 9)

  In the conventional DC vacuum interrupter described above, a signal for operating the thyristor switch 7 is output from the thyristor operation circuit 14 in response to a status signal from the interrupting unit 1a during an accident current and during a normal current. Therefore, even under the condition where no fault current is detected, the thyristor operation circuit 14 is operated by receiving the input of the status signal, so that it is superimposed on the chattering of the contacts constituting the status signal and the line for acquiring the status signal. There was a problem of being severe with respect to noise.

  For this reason, although the signal for operating the thyristor switch 7 is output at the instant of the current rise at the time of the accident current, even if the signal output is slower than at the time of the accident current at the normal current, the signal is hardly affected by noise. It is desirable to be able to operate the thyristor switch 7.

  The present invention has been made to solve the above problems, and provides a direct-current vacuum circuit breaker having improved noise resistance by providing a difference in signal output for operating a thyristor switch between an accident current and a normal current. The purpose is to do.

To achieve the above object, a DC vacuum circuit breaker according to the present invention includes a circuit breaker unit having a main circuit breaker and a sub circuit breaker connected in series to a main circuit, and a commutation current connected in parallel to the main circuit breaker. A commutation unit for injecting a current, a state detection circuit for detecting an open state of the main circuit breaker, a current determination circuit for determining a current value of the main circuit, and a thyristor operation for operating a thyristor switch in the commutation unit A time for operating the thyristor switch by determining the normal current by the current determination circuit rather than the time t1 by which the current determination circuit determines an accident current and operating the thyristor switch. While the time t2 is delayed, the fault current has a duration of 200 μs or more, and the time t1 is 500 μs or less .

  According to the present invention, the thyristor switch that immediately injects the commutation current is operated at the accident current, and the thyristor switch is operated at a later time than the accident current that is hardly affected by the noise at the normal current. The noise resistance is improved and the DC circuit can be cut off reliably.

  Embodiments of the present invention will be described below with reference to the drawings.

  A DC vacuum interrupter according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram showing a configuration of a DC vacuum interrupter according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining signal output in a protection control unit of the DC vacuum interrupter according to an embodiment of the present invention. is there. In addition, in each figure, the same code | symbol was attached | subjected about the component similar to the past.

  As shown in FIG. 1, the DC vacuum interrupter includes an interrupting unit 1a that interrupts the main circuit current, a commutation unit 1b that injects commutation current into the interrupting unit 1a, and a protection control unit 1c that controls injection of commutation current. It consists of

  The breaker unit 1a is provided with a sub-breaker 2 and a main breaker 3 having vacuum valves connected in series. A current transformer 4 (Hall CT) for detecting a current is connected to the main circuit on the power supply side.

  In the commutation unit 1b, a surge absorbing element 8 made of a ZnO element is connected in parallel to a reactor 5, a capacitor 6 and a thyristor switch 7 connected in series. These are connected in parallel between the poles of the main circuit breaker 3. A charging device 9 and a discharging device 10 having a resistor and a switch are connected to both ends of the capacitor 6.

  The protection control unit 1c includes a current detection circuit 11 that detects a current from the current transformer 4, and a current determination circuit 20 that determines whether the current detected by the current detection circuit 11 is an accident current greater than or equal to a predetermined current value. A state detection circuit 12 that detects the open / close state of the circuit breakers 2 and 3 of the circuit breaker unit 1a and an external circuit 13 that opens the circuit breaker unit 1a manually are provided. The outputs of these circuits 20, 12, and 13 are connected to a thyristor operation circuit 14 that operates the thyristor switch 7 and injects a commutation current into the main circuit breaker 3.

  Next, the operation will be described.

  As shown in FIG. 2, when a current is detected by the current detection circuit 11 and an accident current is determined by the current determination circuit 20, the current determination signal is received immediately after the interruption command circuit (not shown) for a time t0, as in the prior art. To output an opening command to the breaking unit 1a. When the main circuit breaker 3 of the breaker unit 1a starts to open and reaches a predetermined gap where insulation recovery is possible, the state detection circuit 12 detects the open state and outputs a state signal.

  The thyristor operation circuit 14 receives the status signal and immediately outputs a signal for operating the thyristor switch 7 at time t1. The time t1 is 500 μs or less, and the duration of the accident current is 200 μs or more. Thereby, the commutation current is superimposed on the accident current, and the accident current is interrupted by the main circuit breaker 3 at the current zero point. Then, the circuit is reliably opened by the auxiliary circuit breaker 2.

  On the other hand, during normal operation, when the signal is input to the external disconnect circuit 13 at time t0 in order to open the blocking unit 1a, the current determination circuit 20 determines the magnitude of the current. This current is a normal current having a predetermined current value in order to turn off the main circuit breaker 3 at the normal time. At time t0, as in the case of the accident current, an opening command is output from an unillustrated interrupting command circuit to the interrupting unit 1a, the main circuit breaker 3 starts to open, and when a predetermined gap is reached, a status signal is output. Is output. However, since the thyristor operation circuit 14 receives the current determination signal determined as the normal current by the current determination circuit 20, the thyristor operation circuit 14 outputs a signal for operating the thyristor switch 7 at time t2.

  The time t2 is set to 5 ms or more that chattering of the contacts constituting the state signal hardly occurs and is not easily affected by noise superimposed on the signal system that takes in the state signal. Thereby, at the time of a normal current, a commutation current is inject | poured in the time t2 later than the time t1, and it interrupts | blocks with the main circuit breaker 3 in a current zero point. In the state signal taken out from the shut-off unit 1a of the main circuit, the noise has a lot of high-frequency components. However, by delaying the operation of the thyristor switch 7 on the order of ms, the attenuation of the noise increases, and the thyristor switch 7 is reliably operated. be able to.

  According to the DC vacuum interrupter of the above embodiment, if the current determination circuit 20 determines that the current is an accident current, a signal for operating the thyristor switch 7 that immediately injects the commutation current is output from the thyristor operation circuit 14, and the normal current and If judged, since the signal is output in a time later than the time of the accident current, the noise resistance of the signal system is improved, and the thyristor switch 7 can be operated reliably.

1 is a circuit diagram showing a configuration of a DC vacuum interrupter according to an embodiment of the present invention. The figure explaining the signal output in the protection control unit of the direct-current vacuum circuit breaker concerning the example of the present invention. The circuit diagram which shows the structure of the conventional DC vacuum interrupter. The figure explaining the signal output in the protection control unit of the conventional DC vacuum interrupter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Breaking unit 1b Commutation unit 1c Protection control unit 2 Sub circuit breaker 3 Main circuit breaker 4 Current transformer 5 Reactor 6 Capacitor 7 Thyristor switch 8 Surge absorption element 9 Charging device 10 Discharging device 11 Current detection circuit 12 State detection circuit 13 External Cutting circuit 14 Thyristor operation circuit 20 Current determination circuit

Claims (2)

An interrupting unit having a main circuit breaker and a sub circuit breaker connected in series to the main circuit;
A commutation unit for injecting a commutation current connected in parallel to the main circuit breaker;
A state detection circuit for detecting an open state of the main circuit breaker, a current determination circuit for determining a current value of the main circuit, and a protection control unit having a thyristor operation circuit for operating a thyristor switch in the commutation unit. Prepared,
The current determination circuit determines that the current is an accident current, and the current determination circuit determines that the current is normal and the time t2 for operating the thyristor switch is slower than the time t1 for operating the thyristor switch .
The accident current has a duration of 200 μs or more,
The direct current vacuum circuit breaker characterized in that the time t1 is 500 μs or less .   2. The thyristor switch operates according to a status signal when the main circuit breaker starts to open and reaches a predetermined gap, and a current determination signal from the current determination circuit. The direct-current vacuum circuit breaker described.

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