JPH0762972B2 - Shiya disconnection control circuit - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a control circuit for a circuit breaker, which is provided in a high-voltage power supply system of a plant and is suitable for protecting a plant device connected to the power supply system and the plant.

[Technical background of the invention]

Generally, in a high-voltage power supply system of various plants, a power supply switch is provided in an appropriate place for the purpose of minimizing an influence when an accident occurs in the power supply system.
Among them, the high-voltage circuit breaker has an absolute mission to block large currents generated in an accident as quickly as possible. Further, normally, a breaker provided with a closing coil and a trip coil separately is used.

Fig. 3 shows an example of such a high-voltage power supply system.
Power is supplied from the main bus composed of RST to the high-voltage equipment 2 via the breaker 1 which has a closing coil and a tripping coil separately. Also, power is supplied from this main bus to the high-voltage equipment 4 via the same circuit breaker 3.

FIG. 2 shows an example of the control circuit of the circuit breaker 1, in which the control power supplies 6-P and 6-N are taken out from the power supplies P and N through the fuses 5-P and 5-N. This control power supply 6-P, 6-
N is a closing signal contact 7-a, a breaker 1-b contact 1-b
1, closing coil 1-CC series circuit and trip signal contact 8
-A, the a-contact 1-a of the circuit breaker 1 and the trip coil 1-TC are connected in parallel to the series circuit, and the trip signal contact 8-a is connected in parallel with the indicator lamp 9 and further the indicator lamp 9 A series circuit of 10 and b-contact 1-b2 of the circuit breaker 1 is connected in parallel.

With the above configuration, when the circuit breaker 1 is opened, the closing signal contact 7-
When a is closed, the contact b 1-b1 of the circuit breaker 1 is closed, so the closing coil 1-CC is excited, the circuit breaker 1 is closed, and the main bus RST supplies power to the high-voltage equipment 2 through the circuit breaker 1. Is supplied. On the contrary, if the trip signal contact 8-a is closed when the circuit breaker 1 is closed, the contact a 1-a of the circuit breaker 1 is closed.
Is closed, the trip coil 1-TC is excited, the circuit breaker 1 is opened, and the power supplied to the high-voltage equipment 2 is cut off. The indicator lamp 10 lights up when the circuit breaker 1 is open and when the control power supplies 6-P and 6-N have voltage. Further, the indicator lamp 9 is provided when the breaker 1 is closed and the trip coil 1-
Lights when the control power supply 6-P, 6-N has a voltage without a break in TC.

[Problems of background technology]

However, in the above-described conventional configuration, even if the trip coil 1-TC is short-circuited, if the closing signal contact 7-a is output, the circuit breaker 1 is once closed and cannot be opened thereafter.

As a result, the high-voltage device 2 affects not only the printing but also the entire printing. At this time, if an internal short-circuit accident occurs in the high-voltage equipment 2, the circuit breaker 1 cannot be opened, so the power supply source of the main bus RST prompts a short-circuit accident, and the main bus RST
The power is cut off and the high-voltage equipment 4 also stops. In this case, if the high-voltage equipment 4 is an important equipment that influences the plant, the entire plant is forced to stop. If the tripping power supply of the circuit breaker provided at the power supply source of the main bus RST is the same as the circuit breaker 1, connect it to the power supply system of the main bus RST and the high-voltage equipment 2, 4 and the main bus RST. There is a risk of causing a major accident in which all the high-voltage equipment in use is burned out. The same is true when the trip coil 1-TC is disconnected.

The above was not a big problem in the era when most of the plant operation was done by remote manual operation, but it is fatal nowadays when automation advances and most of high-voltage equipment is operated by automatic signals. It becomes a defect.

[Object of the Invention]

The present invention, when the circuit breaker is turned on, turns on the circuit breaker after confirming that the trip coil of the circuit breaker is not short-circuited or disconnected, and issues an alarm if an abnormality occurs in the circuit trip coil. An object of the present invention is to provide a circuit breaker control circuit capable of safely protecting plant equipment and the like.

Example of Invention

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 shows a circuit breaker control circuit according to an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts, and the difference from FIG. 2 is that between the trip coil 1-TC or the a-contact 1-a of the circuit breaker 1 the trip coil 1-TC. Relay that operates only when the resistance ratio of
11, the trip signal contact 8-b and the closing signal contact 7-a1 are connected in series to the control power supply 6-P, and the closing coil 1
-CC is to connect the a contact 11-a of the relay 11 and to connect the closing signal contact 7-a2 and the b contact 11-b of the relay 11 to the alarm display device 12.

With the above configuration, the closing signal 7- is provided only when the circuit breaker 1 is open, the control power supplies 6-P and 6-N are sound, and the trip coil 1-TC is not short-circuited or disconnected. When a1 is turned on, the relay 11 operates and the a-contact 11-
The closing coil 1-CC is illustrated by a and the breaker 1 is turned on. However, at this time, the relay 11 limits the current so that the trip coil 1-TC does not reach the operating current.

If the trip coil 1-TC is short-circuited or disconnected even if the closing signal contact 7-a1 is closed, trip coil 1-TC
The relay 11 does not operate because the resistance ratio with At this time, the fact that the alarm display device 12 is abnormal is output by the closing signal contact 7-a2 and the b contact 11-b of the relay 11.

〔The invention's effect〕

As described above, with a simple circuit configuration that operates under the condition that the resistance ratio of the trip coil and the resistance of the relay are constant, the trip coil is short-circuited and disconnected when the breaker closing signal is turned on. It is possible to turn on the circuit breaker after monitoring and confirming, and make a great contribution to the safe operation of the plant.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a circuit breaker control circuit according to an embodiment of the present invention,
FIG. 2 is a conventional circuit breaker control circuit diagram, and FIG. 3 is a system diagram of a high-voltage power supply using a circuit breaker. 1,3 ...... Breaker 1-CC ...... Breaker closing coil 1-TC ...... Breaker trip coil 2,4 ...... High-voltage equipment, 5-P, 5-N ...... Fuse 6-P, 6- N: control power supply, 7: closing signal contact 8: trip signal contact, 9, 10 ... indicator lamp 11 ... relay, 12 ... alarm display device

Claims (1)

[Claims] Claims: 1. A trip signal a contact, a circuit breaker a contact and a trip coil constitute a series circuit to connect to a control power source, a make signal a contact, a trip signal b contact and the trip circuit. A series circuit including a relay having a resistance that operates under a constant resistance ratio between a resistance of the coil and an internal resistance of the coil and that is equal to or lower than the operating current of the trip coil when the make signal a contact operates. And a parallel circuit that connects the input signal a contact to the control power source and connects the relay between the contact a of the breaker and the trip coil, the contact a of the relay, and the breaker of the breaker. A closing coil circuit in which a b-contact and a closing coil form a series circuit and are connected to a control power source, and a series circuit including the closing signal a contact and the relay b-contact. Circuit breaker control circuit, characterized in that it includes an alarm indicator for abnormal alarm display of the trip coil to be connected to.