JP2518400B2 - Fault monitoring device for operating circuits - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a failure monitoring device for an operating circuit, and more specifically, operation such as disconnection of a trip coil provided in a controlled device such as a power receiving device or a disconnecting device. The present invention relates to a monitoring device for monitoring a failure related to a circuit.

[Conventional technology]

This type of trip coil is intended to be operated only in an emergency, such as when an abnormal current flows through the controlled device, and it is necessary for the operator of the device to monitor that it is always in an operable state. It is desired that the monitoring device also has high reliability. FIG. 3 shows an example of such a conventional failure monitoring device for an operating circuit. Here, 1 is a controlled device, 2 is an auxiliary contact (OC) of the controlled device 1, 3 is a trip coil for breaking and breaking, and 4 is a switch (SW1) for trip operation. On the other hand, a current limiting resistor R1 and a relay 5 are provided in parallel with the trip operation switch 4, and an abnormality such as a disconnection of the trip coil 3 is detected via the relay 5.

That is, when the controlled device 1 is turned on, the auxiliary contact 2 is in the "ON" state, and when it is normal, the current limiting resistor R1, the relay
5, current is flowing in the route of the auxiliary contact 2 and the trip coil 3, and it can be seen from the contact output that the trip coil 3 is normal because the relay 5 is in the "ON" state. If there is a wire break in the relay 5, the relay 5 is turned off and the abnormality is detected. In a normal trip operation, by operating the operation switch 4, it is possible to supply a current necessary for the exciting operation of the trip coil 3, and thereby the controlled device 1 can be turned on or off.

[Problems to be Solved by the Invention]

However, in the conventional operating circuit failure monitoring device as described above, when the controlled device 1 is "OFF", the auxiliary contact 2 is in the open state, and therefore the disconnection detection of the trip coil 3 is impossible. Also, when the trip operation switch 4 is operated, the relay 5 is opened and the same relay contact output as that of the trip coil disconnection is obtained. Furthermore, even when the control power supply fails, the relay 5 is opened and the relay contact output is the same as the trip coil disconnection, which is indistinguishable from the coil disconnection.

An object of the present invention is to eliminate the above-mentioned disadvantages of the conventional device,
To provide a monitoring device that detects and outputs only when the trip coil is disconnected, regardless of whether the controlled device is turned on or off, by distinguishing between the trip coil disconnection and a failure such as the presence or absence of an AC control power supply. It is in.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention provides a trip coil for cutting off a controlled device, and an auxiliary contact which is turned on / off according to a closing state and a cutting state of the controlled device,
In a fault monitoring device for an operating circuit for monitoring a fault occurring in an operating circuit in which the trip coil operating switch is connected in series, a resistor connected in parallel with the auxiliary contact, and a trip coil operating switch Is connected in parallel with the AC control power supply connected to the operation circuit half-wave for trip coil disconnection detection, the other half-wave for detecting the connection state of the AC control power supply, the AC control power supply Based on the outputs of the first and second switch means and the first and second switch means, which are respectively energized by the half-wave current, the presence / absence of the outputs of the first and second switch means is used. And a detection circuit that outputs only the disconnection of the trip coil as a state change signal.

According to the present invention, even when the controlled device is in the cut-off state, a current flows through the resistance connected in parallel to the auxiliary contact, so that it is possible to detect the presence / absence of disconnection of the trip coil, and it is possible to detect the disconnection of the first and second operation switches connected in parallel. By the combination of the switch means and the detection circuit, the disconnection of the trip coil and the failure such as the presence or absence of the applied state of the AC control power supply are distinguished, and the state change signal is output from the detection circuit only when the trip coil is disconnected.

[Embodiment of the invention]

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

[Embodiment 1] FIG. 1 shows an embodiment of the present invention. Here, a portion surrounded by a broken line is a failure detection unit involved in failure monitoring and detection. In this example, the resistance R2 is connected in parallel with the auxiliary contact 2.
As long as the trip coil 3 is normal regardless of whether the auxiliary contact 2 is on or off, the current limiting resistance R is applied to the photocoupler PC2 of the detection circuit 10 when the AC1 side of the AC control power supply is.
A half-wave current flows through the diode 3 and the diode D1. Similarly, when the control power supply AC2 side is, a half-wave current flows through the photocoupler PC1 via the diode D2 and the resistor R4.

Furthermore, the capacitor C1 provided in the detection circuit 10 has a resistance
Charging is performed via R5 and discharging is performed alternately via resistor R6, but by setting the capacity of resistor R5 sufficiently larger than that of resistor R6, the capacitor C1 is hardly charged and the comparator The voltage supplied to one input terminal of 11 is always kept below the reference voltage VREF.

Now, in the fault monitoring device configured as described above, if the trip coil 3 is disconnected, no current flows in the photocoupler PC2, and the capacitor C1 is only charged via the resistor R5. R5 and capacitor C1
After that, according to the charging time constant determined by, the charging voltage of the capacitor C1 becomes higher than the reference voltage VREF and the output of the comparator 11 is inverted, so that the disconnection failure can be detected.

Also, assuming that the trip coil 3 is normal and the trip operation switch 4 is operated, current will not flow through the photocoupler PC2 at this time as well, but at the same time, the photocoupler P2 will not flow.
Since the current flowing in C1 flows through the diode D1 and the operating switch 4, it does not flow in the photocoupler PC1,
Therefore, the capacitor C1 is not charged either.

Furthermore, when the control power supplies AC1 and AC2 are not supplied, of course, no current flows through the photocouplers PC1 and PC2,
The capacitor C1 is never charged.

In the detection circuit 10, the resistor R7 shown in broken line provided in parallel with the photocoupler PC1 is the detection circuit 10 and the control power supplies AC1 and AC.
In preparation for an abnormality in the external connection relationship between the photocoupler and the photocoupler regardless of whether the control power supplies AC1 and AC2 are energized by providing such a resistance R7. If PC1 is not activated, this resistor R7
The capacitor C1 is charged via the, and its failure can be detected in the same manner as described above. The resistance R8, which is also shown by the broken line, is added to enable the determination of the cause of the abnormality by utilizing the fact that the charging voltage of the capacitor C1 is different when the photocoupler PC1 is operating and when it is not operating.

[Embodiment 2] FIG. 2 shows another embodiment of the present invention. In this example, a resistor R9 and a diode D3 are provided in parallel with the series circuit of the auxiliary contact 2 and the trip coil 3.
By incorporating the resistor R9 and the diode D3 in the operation circuit on the side, the wiring work becomes unnecessary for the external actual wiring, and the reliability can be improved. In this example, the resistor R9 and the diode D3 function corresponding to the resistor R4 and the diodes D1 and D2 shown in FIG. 1, and other configurations and operations are described in the case of FIG. Since it does not change, its explanation is omitted.

〔The invention's effect〕

As described above, according to the present invention, by providing the resistor in parallel with the auxiliary contact, it is possible to detect the presence or absence of disconnection of the trip coil even when the controlled device is not in the closed state. Connected in parallel with the operation switch, half-wave component of the AC control power supply connected to the operation circuit for detecting the disconnection of the trip coil, the other half-wave component for detecting the connection state of the AC control power supply, Based on the outputs of the first and second switch means and the first and second switch means, which are respectively energized by the half-wave current of the AC control power supply, the outputs of the first and second switch means. By providing a detection circuit that outputs only the disconnection of the trip coil as a state change signal depending on the presence or absence of the above, the disconnection of the trip coil and the abnormal connection state of the AC control power supply can be distinguished. Since the detection function can be improved, the detection function can be improved, and even in the case of remote centralized monitoring, the disconnection of the trip coil can be clearly distinguished from other ones and unnecessary alarms need not be issued. The reliability of the system can be increased.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an example of the configuration of a failure monitoring device for an operating circuit of the present invention, FIG. 2 is a circuit diagram showing the configuration of another embodiment of the present invention, and FIG. 3 is a circuit showing a conventional configuration example. It is a figure. 1 ... Controlled device, 2 ... Auxiliary contact, 3 ... Trip coil, 4 ... Trip coil operation switch, PC1, PC2
...... Photo coupler, R2 to R9 ...... Resistor, C1 ...... Capacitor, 10 ...... Detection circuit, 11 ...... Comparator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Shown 54-95851 (JP, U) Shown 52-75756 (JP, U) Shown 62-123028 (JP, U) Shown 45- 5808 (JP, Y1) Actual public 49-46037 (JP, Y1) Actual public 49-44194 (JP, Y1)

Claims (1)

(57) [Claims] 1. A trip coil for shutting off a controlled device, an auxiliary contact which is turned on / off according to a closed state and a shutoff state of the controlled device, and an operating switch for the trip coil are connected in series. In a failure monitoring device for an operating circuit for monitoring a failure occurring in an operating circuit, a resistor connected in parallel with the auxiliary contact, and a switch for operating the trip coil are connected in parallel, and connected to the operating circuit. A first half of the AC control power supply is used for detecting a break in the trip coil, another half of the AC power supply is used for detecting a connection state of the AC control power supply, and each of which is energized by a current of the half wave of the AC control power supply. And a second switch means, and the first switch based on the outputs of the first and second switch means.
And a detection circuit for outputting only the disconnection of the trip coil as a state change signal depending on the presence or absence of the output of the second switch means.