JPH06267365A - Preventive maintenance device for circuit breaker - Google Patents

Abstract

PURPOSE:To provide a preventive maintenance device for a circuit breaker, which can precisely monitor any abnormality from fluctuation of the operating time of the circuit breaker. CONSTITUTION:Current detectors 71, 72 are connected in series to exciting coils such as a release coil 12 and a closing coil 13, and current flowing through the exciting coils is detected by current level detecting circuits 73, 74 as a command for the starting point of monitoring and information about operation of the auxiliary contacts 14, 15 of a circuit breaker 1 is detected by input fetching circuits 75, 76 as a command for the intermediate stage of monitoring. Further, a micro current Ir flowing through a floating capacitor 3 is detected by a current transformer 2 as a command for the stopping point of monitoring, and a time measuring circuit 82 monitors the operating time of the circuit breaker 1 from the time from the command for the starting point of monitoring to the command for the stopping point of monitoring, and monitors abrasion of a main contact 11 from the time from the command for the intermediate stage of monitoring to the command for the stopping point of monitoring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preventive maintenance device for a circuit breaker.

[0002]

2. Description of the Related Art In general, a circuit breaker used in a power receiving and transforming facility is required to have high reliability because an abnormality of the circuit breaker greatly affects other facilities. In response to this demand, in recent years, in order to predict in advance that the circuit breaker will become abnormal, a preventive maintenance device that captures and monitors various types of preventive maintenance data has been proposed. Known preventive maintenance devices and the like are known.

As such a preventive maintenance device, the current level detection circuit 73 detects that the contact 91a of the auxiliary relay 91 connected in parallel with the release coil 12 of the circuit breaker 1 is closed as shown in FIG. From the main contact 11 of the circuit breaker 1
The time measuring circuit 82 monitors the time until the input capturing circuit 76 detects that the auxiliary contact 14 mechanically connected to the circuit is opened, and when this time exceeds a predetermined time, the circuit breaker 1 It is abnormal and the closing coil 1 of the circuit breaker 1
After detecting that the contact 92a of the auxiliary relay 92 connected in parallel with 3 is closed by the current level detection circuit 74,
The time measuring circuit 82 monitors the time until the input capturing circuit 75 detects that the auxiliary contact 15 of the circuit breaker 1 is closed, and when the time exceeds a predetermined time, it is determined that the circuit breaker 1 is abnormal. Also, as described in Japanese Patent Laid-Open No. 59-180376, there is known one which monitors the time from the current being supplied to the exciting coil such as the release coil of the circuit breaker to the operation of the auxiliary contact of the circuit breaker. Has been.

[0004]

However, in the preventive maintenance device shown in FIG. 2 described above, when attention is paid to the monitoring time, since the starting point is the time when the contacts of the auxiliary relays 91 and 92 operate, these auxiliary relays 91 , 92 when connected to the operating power source P-N, the operating time of the auxiliary relays 91, 92 also changes, and it is determined whether the time fluctuation is due to an abnormality or a voltage fluctuation. Can not do it. In addition, JP-A-59-18
In the preventive maintenance device described in Japanese Patent No. 0376, when attention is paid to the monitoring time, the operation of the auxiliary contact is used as the end point of the monitoring time. However, the interruption of the current causes wear of the main contact of the circuit breaker, which causes the main contact and the auxiliary Since the operating time varies among the contacts, it is still impossible to determine whether the change in the monitoring time is due to an abnormality of the breaker or wear.

An object of the present invention is to provide a preventive maintenance device for a circuit breaker, which can accurately monitor an abnormality from fluctuations in operating time of the circuit breaker.

[0006]

In order to achieve the above-mentioned object, the preventive maintenance device for a circuit breaker according to the present invention detects a current flowing through an exciting coil of the circuit breaker with a current detector, and detects the current. In the preventive maintenance device for the circuit breaker that uses the monitoring start point command to monitor the operating time, the current transformer and the current detector that detect the current flowing through the floating capacitor that changes when the main contact of the circuit breaker operates. The present invention is characterized in that a time measurement circuit that uses the detection as a monitoring start point command and the detection by the current transformer as a monitoring stop end point command and an abnormality determination circuit that compares the monitoring time by the time measurement circuit with a set value are provided. And

In order to achieve the above-mentioned object, the preventive maintenance device for a circuit breaker according to the present invention is the preventive maintenance device for a circuit breaker having an auxiliary contact mechanically connected to a main contact of the circuit breaker. The current transformer that detects the current flowing through the floating capacitor that changes when the main contact of the device operates, and the detection by the auxiliary contact is monitored as an intermediate command.The detection by the current transformer is monitored. The monitoring time until the end point command is measured. And a failure determination circuit that compares the monitoring time of the time measurement circuit with a set value.

[0008]

In the preventive maintenance device for a circuit breaker according to the present invention, as described above, the starting point of the monitoring time is when the current flowing through the exciting coil is detected, and the ending point of the monitoring time is the floating capacitor.
Since the current flowing in the circuit is detected, even if the operating power supply fluctuates in voltage, or even if there is variation between the main contact and auxiliary contact of the circuit breaker due to wear, etc.
The monitoring time can be measured without being affected by these, and therefore the fluctuation of the operating time of the circuit breaker can be accurately monitored by the abnormality determination circuit by comparing the monitoring time with the set value.

Since the preventive maintenance device for a circuit breaker according to the present invention measures the current flowing through the floating capacitor after the auxiliary contact of the circuit breaker operates as described above, both of them are measured. If there is no substantial difference between the two, it means that there is no wear on the main contact of the circuit breaker, and if the difference between the two exceeds a specified value, it is known that the abnormality judgment circuit has worn the main contact of the circuit breaker. Therefore, the abnormality can be accurately monitored from the fluctuation of the operating time of the circuit breaker.

[0010]

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

FIG. 1 is a circuit diagram showing a preventive maintenance device for a circuit breaker according to an embodiment of the present invention.

The distribution line breakers 4, 5 and 6 are connected to the 6.6 KV system via the breaker 1, and the breaker 1 is mechanically connected to the main contact 11 and the main contact 11. It is composed of auxiliary contacts 14 and 15 which are interlocked with each other, and an exciting coil, that is, a releasing coil 12 and a closing coil 13, which are connected between the operating power sources P and N. A release command contact X1 and a current detector 71 are connected in series to the release coil 12 between the operation power supplies P and N, and a close command contact Y1 and a current detector 72 are connected in series to the closing coil 13. The current detectors 71 and 72 are connected to a time measuring circuit 82 via current level detecting circuits 73 and 74, respectively. The auxiliary contacts 14 and 15 of the circuit breaker 1 are connected to the time measuring circuit 82 via the input capturing circuits 76 and 75, respectively.

On the other hand, a current transformer 2 is provided on the distribution line breakers 4, 5, 6 side of the main contact 11 of the circuit breaker 1, and the secondary side of the current transformer 2 is an amplifier 77. , The band pass filter 78, the peak hold circuit 79, and the comparison circuit 81 are connected to the time measurement circuit 82. Comparison circuit 8
1 can set the reference level by the setter 80. It is generally known that the high-voltage switchboards and the high-voltage cables on the distribution line breakers 4, 5, 6 side of the main contact 11 of the circuit breaker 1 have a floating capacitor 3. The output of the time measuring circuit 82 is connected to the trend management device 83 and the abnormality determination circuit 84, and the abnormality determination circuit 84 can set a reference value by the setter 85.

Next, the operation of the preventive maintenance device for the circuit breaker described above will be described.

Since the case of exciting the release coil 12 to open the circuit breaker 1 and the case of exciting the closing coil 13 to close the circuit breaker 1 are similar, here, the release coil 12 is excited to break the circuit breaker. The case of opening 1 will be described.

Normally, the circuit breaker 1 is in a closed state, and when a signal is given to the release command contact X1 due to a failure such as overcurrent, the operating power source P ... Current detector 71 ... Release coil 1
2 ... A current flows between the operating power supply N and the release coil 12 is excited. Therefore, the main contact 11 of the circuit breaker 1 is released by an operating device (not shown), and at the same time, the current level detection circuit 73 detects the current flowing through the release coil 12 and the starting point for starting the measurement of the monitoring time by the time measuring circuit 82 is started. It becomes a command. After that, when the main contact 11 of the circuit breaker 1 is opened, a momentary minute current Ir flows through the floating capacitor 3 existing in the high voltage switchboard and the high voltage cable when the main contact 11 of the circuit breaker 1 is opened and closed. After being detected by the current transformer 2 and amplified by the amplifier 77, the bandpass filter 7
8, the high frequency component 1 to 10 MHz is extracted, the peak hold circuit 79 converts the peak value into a DC component as shown in FIG. 4, and the output of the comparison circuit 81 is given to the time measuring circuit 82. The measurement circuit 82 serves as an instruction to stop measuring the monitoring time. Therefore, the accurate time from the excitation of the release coil 12 to the release of the main contact 11 is measured by the time measuring circuit 82, and its output is input to the abnormality determining circuit 84, and the abnormality determining circuit 84 sets the setter 85. Compared with the preset value set in advance, that is, the set value that takes into consideration the variation due to aging, if it exceeds the set value, it is judged that there is an abnormality, and if it does not exceed the set value, it is judged that there is no abnormality and the trend It is managed by the management device 83. As shown in FIG. 4, the measurement from the excitation of the release coil 12 to the release of the main contact 11 has an advantage that it can be similarly detected regardless of no load and actual load.

Almost at the same time as the opening of the main contact 11 of the circuit breaker 1 described above, the auxiliary contact 15 of the circuit breaker 1 mechanically connected to the main contact 11 is closed, and the input capturing circuit 75 operates to operate the time measuring circuit. An intermediate command for measuring the monitoring time by 82 is given, and in the time measuring circuit 82, the time from the excitation of the release coil 12 to the closing of the auxiliary contact 15 or the current transformer 2 after the auxiliary contact 15 is closed. Then, the time until the minute current Ir instantaneously flowing in the floating capacitor 3 is detected is measured. The time from the excitation of the release coil 12 to the detection of the minute current Ir of the floating capacitor 3 and the time from the excitation of the release coil 12 to the closing of the auxiliary contact 15 should be substantially the same. Alternatively, or after the auxiliary contact 15 is closed, the minute current Ir instantaneously flowing to the floating capacitor 3 in the current transformer 2
If the time until it is detected is almost zero, the abnormality determination circuit 84 determines that it is normal, there is no wear of the main contact 11, and the main contact 11 and the auxiliary contact 15 are operating at the same time as in the initial state. I understand. However, the release coil 1 described above
2 is excited and then a small current Ir of the floating capacitor 3
Is different from the time from when the release coil 12 is excited to when the auxiliary contact 15 is closed, or when the auxiliary contact 15 is closed, the current transformer 2 instantly connects to the floating capacitor 3. If the time until the minute electric current Ir flowing through the target is detected exceeds the set value, the abnormality determining circuit 84 determines that the main contact 11 is abnormally worn.

The above-described operation is shown in a time chart of FIG. 3, and the right half of FIG. 3 corresponds to the case where the release coil 12 is excited to open the circuit breaker 1.

When a break command is given to the release command contact X1 for the circuit breaker 1 in the closed state, the release coil 12 is released.
A TC current as shown in the figure flows through the operating power supplies P and N. When this TC current reaches a detectable current detection level, the current level detection circuit 73 detects this and becomes a measurement start starting point command for the monitoring times TF1 and TF3 by the time measurement circuit 82. In this respect, in the conventional detection time,
As shown in the figure, when the voltage fluctuations of the operating power supplies P and N occur, the measurement start origin command changes within the fluctuation range tα according to this voltage fluctuation, and the abnormality determination value T1 is set correctly. In this case, the monitoring time is affected and the abnormality determination variation occurs within the range shown in the figure. However, since the TC current flowing through the release coil 12 is used as the measurement start point command as described above, even if the voltage fluctuations of the operating power supplies P and N occur, they are not affected and the measurement start point command becomes accurate. After that, in the circuit breaker 1, the main contact 11 is opened after a time TF2, which is a minute current I instantaneously flowing through the floating capacitor 3 present in the high voltage switchboard and the high voltage cable.
r is detected by the current transformer 2 and the monitoring time measurement stop end command is given by the time measuring circuit 82 to obtain the monitoring time TF2. This monitoring time TF2 is compared with a set value T0 in consideration of the variation time t1 due to secular change in the abnormality determination circuit 84, and if it is within the set value T0, it is determined as normal, and if it exceeds this set value T0, it is determined as abnormal. It

When the main contact 11 is opened, the auxiliary contact 15 mechanically connected to the main contact 11 is closed, and the input capturing circuit 75 detects this and the time measuring circuit 82 gives an instruction to stop the measurement of the monitoring time TF1. And monitor time T
I am trying to get F1. This monitoring time TF1 is compared with a set value T0 in consideration of the variation time t1 due to secular change in the abnormality judging circuit 84, and it is judged normal if it is within the set value T0 and abnormal if it exceeds the set value T0. It

Generally, in the circuit breaker, after the initial adjustment, the auxiliary contact 15 is mechanically connected to the main contact 11 and works in synchronism with each other. However, when the main contact 11 is worn due to current interruption, the main contact 11 Will operate later than the auxiliary contact 15. Therefore, although not shown, the abnormality determination circuit 8
By looking at the difference between the monitoring time TF1 and the monitoring time TF2 in FIG. This is because the difference between the monitoring time TF1 and the monitoring time TF2 is obtained by the time measuring circuit 82, and the operation delay time of both is set by the setter 8 shown in FIG.
5, the time difference is compared with the set value by the abnormality determination circuit 84, and if the time difference is within the set value, it can be determined as normal, and if it exceeds the set value, it can be determined as abnormal.

In the above description, the case where the main contact 11 of the circuit breaker 1 is opened is described.
The same effect can be obtained as shown on the left side of FIG. 3 when the main contact 11 is closed by passing an electric current. In either case,
The monitoring time measurement start point command may be obtained from the current flowing through the exciting coil of the release coil 12 and the closing coil 13, and the monitoring time measurement stop point command may be obtained from the minute current Ir instantaneously flowing through the floating capacitor 3.

[0023]

As described above, according to the preventive maintenance device for a circuit breaker according to the present invention, a monitoring time measurement start point command is obtained from the current flowing through the exciting coil, and the monitoring time is obtained from the minute current instantaneously flowing through the floating capacitor. Since the measurement stop end point command is obtained, it is possible to measure the operating time accurately against disturbances such as fluctuations in the operating power supply and without being affected by the wear of the main contact. Preventive maintenance can be performed.

In addition to the above-mentioned structure, the preventive maintenance device for a circuit breaker according to the present invention obtains the measurement intermediate command until the auxiliary contact of the circuit breaker operates, and the time until the measurement intermediate command and the measurement stop end command is reached. Since this is monitored, it is possible to grasp the wear condition of the main contact from this time difference.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a preventive maintenance device for a circuit breaker according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional preventive maintenance device for a circuit breaker.

FIG. 3 is an operation explanatory view of the preventive maintenance device for the circuit breaker shown in FIG. 1.

4 is a processing waveform diagram of a main part of the preventive maintenance device for a circuit breaker shown in FIG.

[Explanation of Codes] 1 Circuit breaker 2 Current transformer 3 Floating capacitor 11 Main contact 12 Release coil 13 Make-up coil 14,15 Auxiliary contact 71,72 Current detector 82 Time measurement circuit 84 Abnormality judgment circuit

Claims (4)

[Claims] 1. A preventive maintenance device for a circuit breaker in which a current flowing through an exciting coil of the circuit breaker is detected by a current detector and a monitoring start point command for monitoring the operating time of the circuit breaker is used as a preventive maintenance device for the circuit breaker. A current transformer that detects the current flowing in the floating capacitor that changes due to the operation of the main contact,
A time measurement circuit that makes the detection by the current detector the monitoring start point command and the detection by the current transformer the monitoring stop point command, and an abnormality determination circuit that compares the monitoring time by the time measurement circuit with a set value. A preventive maintenance device for a circuit breaker characterized by being provided. 2. A preventive maintenance device for a circuit breaker, which has an auxiliary contact mechanically connected to the main contact of the circuit breaker, for detecting a current flowing through a floating capacitor which changes when the main contact of the circuit breaker operates. Monitoring the detection by the current transformer with the detection by the auxiliary contact as the monitoring intermediate command Monitoring the detection time by the current transformer and the time measurement circuit that measures the monitoring time until the end command, and compares the monitoring time by this time measurement circuit with the set value A preventive maintenance device for a circuit breaker, which is provided with an abnormality determination circuit that operates. 3. The device according to claim 2, further comprising a current detector for detecting a current flowing through the exciting coil of the circuit breaker,
The time measuring circuit measures the monitoring time from the monitoring start starting point command to the monitoring stop ending point command by using the detection by the current detector as a monitoring start starting point command for monitoring the operating time of the circuit breaker. A characteristic circuit breaker preventive maintenance device. 4. The current detector according to claim 2, further comprising a current detector for detecting a current flowing through the exciting coil of the circuit breaker,
The time measuring circuit uses the detection by the current detector as a monitoring start starting point command for monitoring the operating time of the circuit breaker, the monitoring time from the monitoring start starting point command to the monitoring stop end point command, and the detection by the current detector. Is a monitoring start point command for monitoring the operating time of the circuit breaker, and the difference from the monitoring time from the monitoring start point command to the monitoring intermediate command by the auxiliary contact is measured. Preventive maintenance device.