JP3248519B2 - Submarine cable discharge circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a discharge circuit,
In particular, the present invention relates to a discharge circuit for discharging residual charges of a submarine cable in a submarine cable system.

[0002]

2. Description of the Related Art As shown in FIG. 3, in a submarine cable system in which a high-voltage output end of a power supply device C is connected to a conductor E of a submarine cable D, when an open fault of a long-distance submarine cable or a fault is detected, the submarine cable is used. As shown in the figure, a worker generally discharges a discharge rod A having an internal resistance at first with a discharge rod A having one end connected to the ground, and then a discharge rod A having an internal resistance. In addition, the discharge rod B for short-circuit is directly touched to the conductor portion to artificially discharge.

[0003]

In this case, since the worker touches the high-voltage portion while holding the discharge rod in his hand, it is inevitable that the worker feels fear of electric shock.

[0004] It is an object of the present invention to provide a submarine cable discharge circuit having a discharge function that enables an operator to safely and easily work when discharging residual charges in a submarine cable.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a discharge circuit for discharging residual charges in a conductor E of a submarine cable D connected to a high-voltage output terminal of a power supply device C. And a resistor R for connecting the conductor E to the ground,
A first high voltage relay RL1 and a second high voltage relay RL
2, a first contact rl1 that is connected between the conductor E and the resistor R, is closed by the operation of the first high-voltage relay RL1, and discharges the residual charge of the conductor E through the resistor R; A second contact rl2 connected in parallel and closed by the operation of the second high voltage relay RL2 to short-circuit the resistance;
Timer circuit 3 that activates the second high withstand voltage relay RL2 after a certain period of time after the high withstand voltage relay RL1 is operated
And a sequence circuit 1/10 for suppressing the activation of the first high-voltage relay RL1 during the operation of the power supply device C.

Preferably, the first sequence circuit 1 having the first starting input a controls the first high-voltage relay RL1 (eg, a vacuum relay) via the first drive circuit 2 to operate. And the first sequence circuit 1
Operates so as to receive the signal d during the operation of the power supply device and to suppress the first start-up input a, and that the second sequence circuit 10 having the second start-up input b 20 to control the second high voltage relay RL2 to be activated, and the output of the first sequence circuit 1 to the first drive circuit 2 is simultaneously input to the timer circuit 3; The output of 1 acts on the second sequence circuit 10 so as to suppress the second start-up input b for a certain time (for example, one minute), and the second output of the timer circuit 3 becomes after a certain time ( For example, after 2 minutes), the second high-voltage relay RL2 is automatically activated via the second drive circuit 20, and the reset signal input c is applied to the first drive circuit 2 and the second drive circuit RL2. Input to the drive circuit 20 of the first Act to cancel the breakdown voltage relay RL1 and the second high-voltage relay RL2 simultaneously, first
One end of the contact rl1 of the high voltage relay RL1 is connected to the conductor of the submarine cable, and the other end is connected to the ground via the resistor R.
The contact rl2 of the second high voltage relay is connected to both ends of the resistor R.

[0007]

According to the present invention, the first high voltage relay RL1 can be operated by inputting a signal to the first starting input. Thereby, the contact rl of the first high voltage relay
1 is closed and the residual charge of the conductor of the submarine cable can be discharged via the resistor R. This operation is suppressed so that the first high withstand voltage relay does not operate while the power supply device is operating. Next, when a signal is input to the second starting input after a predetermined time, the second high withstand voltage relay can be operated. As a result, the contact rl2 of the second high-voltage relay is closed, and the resistor R is short-circuited, so that the residual charge of the conductor of the submarine cable is completely discharged. The second high withstand voltage relay automatically operates by the operation of the timer circuit a predetermined time after the first activation input even if there is no second operation activation input, and the residual charge is completely discharged. . The high breakdown voltage relays RL1 and RL2 can be released from operation at any time by inputting a reset signal.

[0008]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing one embodiment of a discharge circuit according to the present invention. In the figure, a high-voltage output end of a power supply device C is connected to a conductor E of a submarine cable D, and a discharge circuit F according to the present invention is
Used to connect to.

The discharge circuit F includes a first sequence circuit 1 activated by a first activation input a, a first drive circuit 2 controlled by the first sequence circuit 1, and a first drive circuit 2 controlled by the first sequence circuit 1. The first activated by the drive circuit 2
High voltage relay (for example, a vacuum relay) RL1, a second sequence circuit 10 activated by a second activation input b, and a second high voltage relay (for example, operated by the second drive circuit 10) Vacuum relay) RL2, timer circuit 3, and resistor R for connecting conductor E to ground.
A make contact rl1 of the first high voltage relay RL1,
And the make contact rl2 of the second high withstand voltage relay RL2.

Then, the first sequence circuit 1 controls the first high-voltage relay RL1 to operate via the first drive circuit 2, and the first sequence circuit 1 operates during the operation of the power supply device. In response to the signal d, the first activation input a acts so as to be suppressed, and the second sequence circuit 10
A second high voltage relay R via the second drive circuit 20;
Control is performed to activate L2.

The output of the first sequence circuit 1 to the first drive circuit 2 is input to the timer circuit 3 at the same time, and the first output of the timer circuit 3 is supplied to the second sequence circuit for a certain period of time. 10, the second output of the timer circuit 3 automatically outputs the second high-voltage relay RL2 via the second drive circuit 20 after a certain period of time. It works to operate.

The reset signal input c is input to the first drive circuit 2 and the second drive circuit 20, and the first high voltage relay RL1 and the second high voltage relay RL
2 are simultaneously released, one end of the make contact rl1 of the first high-voltage relay RL1 is connected to the conductor of the submarine cable, and the other end is connected to the ground via the resistor R. Make contact rl2 is configured to be connected to both ends of resistor R.

Next, the operation of the discharge circuit F having the above configuration will be described. In FIGS. 1 and 2, by inputting a signal to the first starting input a (t = t1), the first high-voltage relay RL1 is output via the first sequence circuit.
Operates. Thereby, the contact rl of the first high voltage relay
1 is closed and the residual charge of the conductor of the submarine cable is discharged via the resistor R. This operation is performed while the power supply device is operating.
The high withstand voltage relay is suppressed in the first sequence circuit so as not to operate.

Next, after a certain time (t2 ≦ t3 ≦ t4),
When a signal is input to the second starting input b, the second high voltage relay RL2 operates via the second sequence circuit. As a result, the contact rl2 of the second high-voltage relay is closed, and the resistor R is short-circuited, so that the residual charge of the conductor of the submarine cable is completely discharged. This second high voltage relay RL2
Is activated automatically by the operation of the timer circuit after a certain time (t = t4) after the first activation input a even if the second operation activation input b does not exist, so that the residual charges are completely discharged. Will be The high breakdown voltage relays RL1 and RL2 cancel their operations by inputting the reset signal c (t = t5).

[0015]

As described in detail above, the discharge circuit according to the present invention discharges the residual charge of the conductor of the submarine cable without the need for the operator to directly touch the high-voltage part with a discharge rod or the like as in the prior art. By controlling the high withstand voltage relay as the discharging means, there is an effect that the residual charges can be discharged safely and reliably.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a discharge circuit according to the present invention.

FIG. 2 is a time chart showing the operation of the present invention.

FIG. 3 is a diagram showing a conventional means using a discharge rod.

[Explanation of symbols]

 C Power supply device D Submarine cable E Conductor F Discharge circuit a, b Control signal input c Reset signal input d Power supply device operation signal 1, 10, Sequence circuit 2, 20 Drive circuit 3 Timer circuit RL1, RL2 High voltage relay rl1, rl2 High withstand voltage Relay contact R resistance

Claims (2)

(57) [Claims] 1. A discharge circuit connected to a conductor of a submarine cable connected to a high-voltage output end of a power supply device to discharge residual charges in the conductor, a resistor for connecting the conductor to ground, A first high-voltage relay, a second high-voltage relay, connected between the conductor and the resistor, closed by the operation of the first high-voltage relay, and the residual charge of the conductor is passed through the resistor. A first contact to be discharged, a second contact connected in parallel with the resistor, closed by operation of the second high withstand voltage relay to short-circuit the resistor, and a constant after the first high withstand voltage relay is operated A discharge circuit for a submarine cable, comprising: a timer circuit that activates the second high-voltage relay after a time; and a sequence circuit that suppresses activation of the first high-voltage relay while the power supply device is operating. circuit. 2. A first sequence circuit having a first start-up input controls a first high voltage relay via a first drive circuit to operate, the first sequence circuit comprising: The second sequence circuit having the second start-up input acts to suppress the first start-up input in response to the signal during the operation of the power supply device, and the second sequence circuit having the second start-up input receives the second start-up input via the second drive circuit. The high-voltage relay is controlled to operate, and the output of the first sequence circuit to the first drive circuit is simultaneously input to the timer circuit. The first output of the timer circuit is the second output for a certain period of time. The second output of the timer circuit automatically activates the second high-voltage relay via the second drive circuit after a certain period of time, acting on the sequence circuit to suppress the second start-up input. And the reset signal The first and second high-voltage relays are input to the first and second high-voltage relays to simultaneously release the first and second high-voltage relays. One end of a contact of the first high-voltage relay is connected to a conductor of the submarine cable, and the other end is connected to a resistor. Connected to ground via
2. The discharge circuit for submarine cables according to claim 1, wherein the contacts of the second high voltage relay are connected to both ends of the resistor.