JPH0646522A - Normal supervisory unit for circuit breaker operation control circuit - Google Patents

Abstract

PURPOSE:To realize constant and simultaneous supervision of an operating coil and an operating switch by employing duplex operating switch and comparing the voltage distribution of resistors connected in parallel with respective switch elements with a normal voltage distribution. CONSTITUTION:Electric resistors 9, 10 are connected in parallel with switch elements 5, 6 while an electric resistor 11 is connected in parallel with an auxiliary contact 3. A supervisory control circuit 12 drives each switch element and executes comparison operation between each terminal voltage and a reference voltage. For the purpose of supervision of a trip operation circuit 8, a state where both switch elements 5, 6 are turned OFF, a state where only the switch element 5 is turned OFF, and a state where only the switch element 6 is turned OFF are set and each state is reproduced cyclically. Any failure exhibits a voltage distribution different from normal one regardless of the closed state or tripped state of circuit breaker. This constitution realizes constant supervision of failure in the operating switch as well as in the operating coil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker operation control circuit continuous monitoring apparatus for constantly monitoring an operation control circuit for performing a circuit breaker closing operation and a tripping operation.

[0002]

2. Description of the Related Art As is well known, an operation control circuit for closing and tripping a circuit breaker comprises an operation control switch, an operation control coil, and an auxiliary contact that opens and closes in tandem with the open / close state of the circuit breaker. Connected and configured. In the conventional constant monitoring for the failure of the operation control circuit, only the disconnection of the operation control coil is detected.

FIG. 3 shows a conventional example thereof. This example is a control circuit for tripping operation, and an operating switch 1 for tripping operation and a trip coil 2 are provided between control power lines P and N. And an auxiliary contact 3 that opens and closes in conjunction with the open / close state of the circuit breaker are connected in series. Tripping coil 2
A monitoring device 4 is connected in parallel to the trip coil 2 for detecting the disconnection of the.

In order to trip the circuit breaker in the closed state (the auxiliary contact 3 is turned on at this time), the operation switch 1 may be turned on, whereby the trip coil 2 is excited. The circuit breaker is tripped. Monitoring for detecting disconnection of the trip coil 2 is performed by causing a current equal to or lower than the operating current to flow through the trip coil 2 and monitoring the current value at that time by the monitoring device 4.

However, according to such a configuration, even if it is possible to monitor the disconnection detection of the trip coil, it is not possible to monitor the operation switch. This is because when the operation test of the operation switch is performed, the operation current flows and the circuit breaker operates, and when the operation switch is a mechanical relay contact, the switching life is shorter than that of the semiconductor switch. , Based on the reason that it cannot be monitored frequently and constantly.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to always monitor a failure of an operation control circuit including not only an operation coil but also an operation control switch.

[0007]

The present invention provides an operation control switch circuit in which a first switch element and a second switch element are connected in series, and an operation control coil for closing or tripping a circuit breaker, An operation control circuit is configured by connecting in series an auxiliary contact that is opened / closed in conjunction with the open / closed state of the circuit breaker, and an electric resistance is provided in parallel with each of the first switch element, the second switch element and the auxiliary contact. A first switch that is connected and that simultaneously turns off the first switch element and the second switch element
, A second state in which only the first switch element is turned off, and a third state in which only the second switch element is turned off are cyclically generated, and first to third
In this state, each terminal voltage of the electric resistances connected in parallel to the first switch element and the second switch element is compared with the reference voltage, and the first switch element, the second switch element and the operation control coil are compared. It is characterized by comprising a comparison detection means for detecting an abnormality of the operation control circuit based on a difference between each terminal voltage in a normal state and each terminal voltage in an abnormal state.

[0008]

The operation control coil is excited by simultaneously turning on and off the first and second switch elements.
Whether the circuit breaker is closed or tripped,
The first to third states are cyclically generated. First
The terminal voltage of each electric resistance is different when the second switch element and the operation control coil are all normal and when any one of them is abnormal. Therefore, by comparing this voltage with the reference voltage, it is possible to detect an abnormality in each switch element and the operation control coil.

[0009]

Embodiments of the present invention will be described with reference to the drawings. Figure 3
The operation circuit of the trip coil will be described below as an example. In addition, the part given the same code as FIG. 3 shows the same or corresponding part. According to the present invention, the switch circuit 7 is configured by connecting the first switch element 5 and the second switch element 6 in series. Semiconductor switch elements are used as the switch elements 5 and 6, for example. The switch circuit 7 is connected in series to the trip coil 2 and the auxiliary contact 3 to form an operation control circuit, that is, a trip operation circuit 8, which is connected between the control power supply lines P and N.

Electrical resistances 9 and 10 are connected in parallel to the switch elements 5 and 6, respectively. Further, an electric resistance 11 is connected in parallel with the auxiliary contact 3. Reference numeral 12 is a supervisory control circuit, to which the terminal voltage V1 of the electric resistance 9 and the terminal voltage V2 of the electric resistance 10 and the control power supply voltage from the control power supply line P are given as reference voltages. Then, each switch element is driven for monitoring, and a comparison operation between each terminal voltage and the reference voltage is executed.

When the circuit breaker is in the closed state, both switch elements 5 and 6 are turned on by a drive circuit (not shown). As a result, the trip coil 2 is driven and the breaker is tripped. The auxiliary contact 3 is turned off by this tripping operation. These operations are not particularly different from the conventional configuration.

For monitoring the tripping operation circuit 8, both the switch elements 5 and 6 are off (first state), only the switch element 5 is off (second state), and only the switch element 6 is present. Is set to the off state (third state).
Each state is cyclically reproduced. This is executed by driving each switch element by a signal issued from the monitor control circuit 12 according to a predetermined program.

Terminal voltages V1 and V2 are generated in the electric resistances 9 and 10 corresponding to the first to third states. This voltage causes an excessive response due to the inductance of the trip coil 2, but when it reaches a steady value, it becomes a voltage value determined for each state.

However, disconnection may occur in the trip coil 2,
When the switch elements 5 and 6 are not in the normal operating state, that is, when they are in a failure state, the voltage distribution values are different from those in the normal state. Table 1 shows the voltage distribution in such a case in comparison with the voltage distribution in the normal state.

The failure status indicates a disconnection of the trip coil 2, a short-circuit failure of the switch elements 5 and 6 (including a case where a failure of the drive circuit is caused), and an open failure. For simplification, each voltage value is shown as a ratio when the control power supply voltage is set to 1, and the case where the resistance values of the electric resistances 9 to 11 are set equal is shown. In the table, a symbol-indicates that a failure is detected in the output voltage in the previous state, the failure is displayed, and then the next state is not progressed.

[0016]

[Table 1]

As is clear from Table 1, even if the circuit breaker is in the closed state or the tripped state, any failure shows a voltage distribution different from the normal voltage distribution in any of the states 1 to 3. Can understand. Therefore, the occurrence of a failure can be detected by giving a voltage distribution in a normal state as a reference voltage for comparing each state. Further, when the control power supply voltage of the control power supply lines P and N fluctuates, the fluctuation can be compensated by using the control power supply voltage as a reference voltage.

The monitoring is always performed by cyclically raising states 1 to 3. If a trip command is generated during monitoring, this can be used as an interrupt input to stop the cyclic for monitoring, and restart the cyclic after the closing operation or the trip operation is completed. It is also possible to display the details of the failure by logically operating the comparison result of the voltage distribution described above.

FIG. 3 shows an example of the monitor control circuit 12. The program stored in the program storage unit 20 is decoded by the arithmetic processing unit 19 of the microcomputer, and the switch elements 5 and 6 are cyclically driven at set time intervals. 21 is an external interface circuit for that purpose, 2
2 is a drive circuit for the switch element 5, 23 is a drive circuit for the switch element 6, and 24 is a display circuit for displaying the details of the failure.

The voltages V1 and V2 and the control power supply voltage V are given to the input converter 13, where they are stepped down to a voltage suitable for input, reduced in noise through the analog filter 14, and then held in the sample hold circuit 15. . And
The data of these voltage signals are sequentially switched by the multiplexer 16, converted into a digital signal by the A / D converter 17, and temporarily stored in the A / D conversion data memory 18.

Of these data, the switch element 5,
By the operation processing unit 19 reading the data after a lapse of a fixed time after the drive command of 6, the malfunction due to the rising characteristic of the voltage waveform can be eliminated. Compare this data with the voltage distribution data specified in the program,
If there is a difference, a command to turn off both the switch elements 5 and 6 is output to the drive circuits 22 and 23, and the failure content is displayed on the display circuit 24 via the interface circuit 21.

When a trip command is issued during these cyclic monitoring operations, this command is issued to the arithmetic processing unit 19.
Is input to the drive circuits 22 and 23 of the switch elements 5 and 6 immediately after the operation processing section 19 stops the monitoring operation based on the program. As shown in Table 1, the trip operation is confirmed by voltage V1,
This is possible from the voltage distribution of V2. After the confirmation, the monitoring operation is restarted.

Since the voltage waveform is an excessive waveform as described above, the reliability of the operation is improved by comparing the voltage waveform with the steady voltage value in consideration of the rising of the waveform. Further, for this kind of operation circuit, a power semiconductor element that is fast in switching and has a long switching life is suitable. By duplicating the switch element and constantly monitoring itself, the switch element can be used with high reliability.

Although the above description is an example of the tripping operation circuit, it goes without saying that the present invention can be similarly applied to the closing operation circuit.

[0025]

As described above, according to the present invention, in the operation circuit of the circuit breaker, not only the operation coil but also the operation switch can be constantly monitored for each failure.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of the supervisory control circuit of FIG.

FIG. 3 is a circuit diagram of a conventional example.

[Explanation of symbols]

 2 Operation coil (tripping coil) 3 Auxiliary contact 5 First switch element 6 Second switch element 7 Operation control switch circuit 8 Operation circuit (tripping operation circuit) 9 Electric resistance 10 Electric resistance 11 Electric resistance 12 Monitoring control circuit

Claims (6)

[Claims] 1. An operation control switch circuit in which a first switch element and a second switch element are connected in series, an operation control coil for turning on or off a circuit breaker, and an open / close state of the circuit breaker. And an auxiliary contact that is opened and closed in series to form an operation control circuit, and an electric resistance is connected in parallel to each of the first switch element, the second switch element and the auxiliary contact. A first state in which the first switch element and the second switch element are turned off at the same time, and a second state in which only the first switch element is turned off
And a state generating means for cyclically generating a third state in which only the second switch element is turned off,
In the first to third states, each terminal voltage of electric resistances connected in parallel to the first switch element and the second switch element is compared with a reference voltage,
Comparison detecting means for detecting an abnormality of the operation control circuit based on the difference between the terminal voltages in the normal state of the switch element, the second switch element and the operation control coil and the terminal voltages in the abnormal state. A continuous monitoring device for an operation control circuit for a circuit breaker. 2. The continuous monitoring device for an operation control circuit for circuit breaker according to claim 1, wherein the reference voltage is a power supply voltage of the operation control circuit. 3. The continuous monitoring device for an operation control circuit for circuit breaker according to claim 1 or 2, wherein the first switch element and the second switch element are semiconductor switch elements. 4. The method according to claim 1, wherein comparison is made with a reference voltage after a rise time of a waveform of each terminal voltage of the electric resistance.
A continuous monitoring device for an operation control circuit for a circuit breaker according to the item 3 or 3. 5. An apparatus for constantly monitoring a circuit breaker operation control circuit according to claim 1, 2, 3, or 4, wherein the comparison and detection means is provided with means for displaying a failure content. 6. A patent comprising means for stopping the operation of the comparison detection means by using the inputs of the closing command and the tripping command as interrupt inputs and restarting the operation of the comparison detecting means after the completion of the closing operation and the tripping operation. Claims 1st, 2nd, 3rd
A continuous monitoring device for an operation control circuit for circuit breaker according to item 4, item 5 or item 5.