JPH05252646A - Detecting device for deterioration of insulation - Google Patents

Abstract

PURPOSE:To provide a deterioration of insulation detecting device, capable of realizing the prediction of leak, by monitoring the change of leakage current. CONSTITUTION:A breaker 1 for wiring, which is equipped with an opening and closing contact 7 interposed in a wiring and opened upon overload or shortcircuit as well as a zero-phase current transformer 8 provided in the wiring and provided with an earth leakage breaker function, is provided. An extracting unit 21, taking out the output of the zero-phase current transformer 8, is provided. A comparing and indicating unit 23, connected to the extracting unit 21 and monitoring the zero-phase current transformer 8, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulation deterioration detecting device for monitoring the condition of insulation deterioration of wiring.

[0002]

2. Description of the Related Art Conventionally, an earth leakage breaker has been provided in an indoor wiring in case the insulation deteriorates and an electric leakage occurs. That is, the conventional general earth leakage breaker has a zero-phase current transformer provided in the wiring, and when an output is generated in the zero-phase current transformer due to leakage, this output reaches a predetermined current value. At this point, the switching contact is opened and the power is shut off.

Further, in an important wiring which does not want to shut off the power source, for example, Japanese Patent Laid-Open No. 3-210727 (H0
1H83 / 02), an earth leakage breaker with overload / short-circuit protection function is provided, and the output of the zero-phase current transformer provided in the wiring reaches a value equivalent to the predetermined earth leakage current value. At that point, an alarm is issued instead of opening the contact.

[0004]

As described above, in each of the conventional earth leakage circuit breakers, the output of the zero-phase current transformer that opens the switching contact or issues an alarm corresponds to an earth leakage current of, for example, 15 mA or 30 mA. The value is predetermined, and it does not operate until insulation deterioration reaches a dangerous state, and
Since the operation is performed suddenly, the progress of insulation deterioration cannot be grasped. However, the insulation deterioration of the wiring does not occur suddenly, but in many cases, it gradually progresses. Therefore, if it is possible to grasp the progress of this deterioration, it is possible to predict the leakage and take appropriate measures before the leakage breaker operates, but conventionally, this can be confirmed only by an insulation resistance test. There was a problem that the wiring path had to be cut off in order to carry out the test.

By the way, in recent years, there has been considered an earth leakage breaker provided with a monitoring terminal for monitoring the output of the zero-phase current transformer as described in the above publication.

Therefore, the present invention provides an insulation deterioration detecting device capable of realizing the prediction of the leakage by monitoring the change of the leakage current based on the conventional situation.

[0007]

That is, an insulation deterioration detecting device C according to the invention of claim 1 is provided with a switching contact 7 which is interposed in a wiring and is opened when an overload or a short circuit occurs, and a zero provided in the wiring. A circuit breaker 1 having a leakage current interruption function, which is provided with a phase current transformer 8, an extraction unit (extraction unit) 21 for extracting the output of the zero-phase current transformer 8, and a connection to the extraction unit (extraction unit) 21. And a monitoring means (comparative display section) 23 for monitoring the output of the zero-phase current transformer 8.

Further, the insulation deterioration detecting apparatus C according to the invention of claim 2 is provided with a switching contact 7 provided in the wiring and a zero-phase current transformer 8 provided in the wiring, and a zero-phase current change. The output of the earth leakage breaker (wiring circuit breaker with earth leakage interruption function) 1 that opens the switching contact 7 when the output of the equipment 8 reaches a predetermined value and the output of the zero-phase current transformer 8 It is composed of an earth leakage warning means (comparative display section) 23 for issuing a warning at an output of a value lower than the output of the zero-phase current transformer 8 in which the contact 7 is opened.

Further, the insulation deterioration detecting device C according to the third aspect of the present invention comprises a circuit breaker 25 having a switching contact 7 interposed in the wiring and opened at the time of overload and a short circuit, and the latter stage of the switching contact 7. The zero-phase current transformer 8 provided on the wiring (wiring path) 26 and the monitoring means (comparison display unit) 23 for monitoring the output of the zero-phase current transformer 8.

[0010]

According to the insulation deterioration detecting apparatus C of the present invention, the output of the zero-phase current transformer 8 included in the circuit breaker 1 for the wiring having the earth leakage breaking function is extracted, and the extracted output is used. Based on this, the change of the leakage current can be monitored by the monitoring means (comparative display unit) 23. This makes it possible to grasp the status of insulation deterioration and predict leakage.

According to the insulation deterioration detecting device C of the second aspect of the present invention, there is provided an earth leakage breaker (wiring circuit breaker having an earth leakage interruption function) 1
Is used to extract the output of the zero-phase current transformer 8 of the circuit, and the earth leakage warning means (comparison display unit) 23 issues an alarm at an output value lower than the output value at which the earth leakage breaker opens the switching contact 7. Therefore, a warning can be given before the wiring is cut off by the earth leakage breaker, and the user can be made aware of the occurrence of earth leakage.

According to the insulation deterioration detecting apparatus C of the third aspect of the present invention, the leakage current is detected in the subsequent stage of the normal circuit breaker 25 having no leakage interruption function, and the monitoring means (comparison display section) is based on the output thereof. ) 23, it is possible to monitor changes in the leakage current. This makes it possible to grasp the condition of insulation deterioration and predict leakage.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows an electric circuit diagram of an insulation deterioration detecting device C of the present invention. In FIG. 1, a circuit breaker 1 for a wiring with an earth leakage breaking function includes an input terminal 2 and an output terminal 3 connected to a three-phase AC indoor wiring, a wiring path 4 as wiring between both terminals 2 and 3, and this wiring. It is provided with an overcurrent detecting bimetal 6 and an opening / closing contact 7 provided in the path 4, and a zero-phase current transformer 8 arranged so as to surround the wiring path 4.

The voltage across the leakage detection unit 9 which is the coil of the zero-phase current transformer 8 is input to the leakage comparison output unit 11, and the output of the leakage comparison output unit 11 has an alarm output contact 17 provided with an alarm output. Coil of relay 12 and leakage indicator lamp 13
Are connected. A test button 14 and a leakage operation button 16 are further connected to the leakage comparison output unit 11.

The operation of the circuit breaker 1 for a circuit with the earth leakage breaker having the above structure will be described. When an overload or a short circuit occurs in the wiring and an overcurrent flows in the wiring path 4, the bimetal 6 bends to open the switching contact 7. As a result, the wiring path 4 is shut off to prevent damage to subsequent devices. Further, when a leakage occurs in the wiring, the vector sum of the three-phase currents flowing through the wiring path 4 does not become 0, whereby a magnetic flux is generated in the zero-phase current transformer 8 and a voltage is generated across the leakage detection unit 9. Leakage comparison output unit 1
1 operates, for example, when a voltage corresponding to a leakage current of 30 mA appears in the leakage detection unit 9, opens the open / close contact 7, and disconnects the wiring path 4. This prevents electric shock accidents and fires due to electrical leakage.

At the same time, the leakage comparison output unit 11 generates an output to close the alarm output contact 17 of the alarm output relay 12 and sounds a buzzer (not shown) connected thereto, or a leakage display device provided in a remote guard room or the like. Is activated to notify the occurrence of leakage. The operation of the alarm output relay 12 is displayed to the outside by the lighting of the leakage indicator lamp 13. Further, the leakage comparison output unit 11 pushes out the leakage operation button 16 when the opening / closing contact 7 is opened due to the occurrence of the leakage, thereby making it possible to identify whether the opening / closing contact 7 is manually opened or the leakage is opened. Further, in order to confirm the operation of the circuit breaker 1 for wiring with the earth leakage breaker function, for example, by operating the test button 14 once a month, the earth leakage comparison output unit 11 is artificially generated and operates. Can be done.

To both ends of the leakage detecting section 9 of the circuit breaker 1 for wiring with an earth leakage interrupting function as described above, an extracting section 21 composed of a voltage dividing resistor is connected as an extracting means. This extraction unit 21
The terminal voltage of the voltage-dividing resistor forming the circuit is drawn out to the outside of the circuit breaker 1 for a circuit with an earth leakage breaker function by a lead wire 22 and input to a comparison display section 23 as a monitoring means composed of a personal computer or the like. There is.

The comparison display unit 23 is installed in the central control department such as the security room, and constantly monitors the change of the leakage current based on the voltage taken out from the extraction unit 21 to thereby insulate the circuit and the equipment. The progress of deterioration is displayed on the monitor by a number corresponding to the leakage current, for example. Further, the comparison display unit 23, for example, the input value corresponding to the output voltage of the leakage detection unit 9 corresponding to the leakage current of 5 mA to 10 mA, which is less than 30 mA which is the set value of the leakage comparison output unit 11, as a threshold value, The inputs from the extraction unit 21 are compared, and a warning is issued when the leakage current exceeds the threshold value. By these monitoring operations, the user can constantly grasp the current progress of insulation deterioration and predict the future occurrence of serious leakage, and thereby the leakage comparison output unit 11 opens the switching contact 7. Before that, it becomes possible to repair the faulty part of the earth leakage.

Here, even if the earth leakage comparison output unit 11 operates and the switching contact 7 opens, it is difficult to repair it immediately at night or on a holiday, causing serious damage due to power failure. easy. However, according to the present invention, the comparative display unit 23 constantly monitors the progress of the leakage,
Since measures can be taken in advance, it is possible to prevent inconveniences such as the sudden disconnection of the wiring by the earth leakage breaker as in the conventional case, and it is possible to achieve a remarkable effect in terms of equipment maintenance. Particularly in an important circuit where it is not desired to turn off the power supply, there is an advantage that the failure can be dealt with at a minor stage before it develops into a serious failure.

Next, FIG. 2 shows an electric circuit diagram in the case of constructing the insulation deterioration detecting device C of the present invention by using the normal circuit breaker 25 which does not have an earth leakage breaking function. In addition, in FIG.
The components denoted by the same reference numerals as are the same, and the description thereof is omitted.

In this case, the circuit breaker 25 for wiring has the above-mentioned overload / short-circuit protection function, but does not have a zero-phase current transformer. 26, the zero-phase current transformer 8 is provided so as to surround it. The voltage across the leakage detection unit 9 of the zero-phase current transformer 8 is directly connected to the lead wire 22 and the comparison display unit 23 to perform the same monitoring / warning operation as described above.

[0022]

As described above in detail, according to the invention of claim 1, the output of the zero-phase current transformer included in the circuit breaker for wiring having the earth leakage breaker function is extracted, and based on the extracted output. Since the change of the leakage current can be monitored by the monitoring means, it is possible to grasp the state of the insulation deterioration of the wiring and predict the leakage. Therefore, it is possible to perform a treatment before the power is cut off, it is possible to prevent the power from being suddenly cut off as in the conventional case, and it is possible to obtain a remarkable effect in terms of maintenance of the device.

According to the second aspect of the present invention, an output value lower than the output value at which the output of the zero-phase current transformer included in the earth leakage breaker is extracted and the earth leakage breaker opens the switching contact. Since the earth leakage warning means gives a warning, it is possible to warn the user before the wiring is cut off by the earth leakage breaker and to let the user predict the occurrence of earth leakage. Therefore, it is possible to perform a treatment before the power is cut off, it is possible to prevent the power from being suddenly cut off as in the conventional case, and it is possible to obtain a remarkable effect in terms of maintenance of the device.

Further, according to the third aspect of the present invention, the leakage current is detected in the subsequent stage of the normal circuit breaker having no leakage interruption function, and the change of the leakage current is monitored by the monitoring means based on the output thereof. Since it is possible to grasp the situation of insulation deterioration of the wiring, it becomes possible to predict leakage.
Therefore, it is possible to perform a treatment before the power is cut off, it is possible to prevent the power from being suddenly cut off as in the conventional case, and it is possible to obtain a remarkable effect in terms of maintenance of the device.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an insulation deterioration detecting device using a circuit breaker for wiring with an earth leakage breaking function.

FIG. 2 is an electric circuit diagram of an insulation deterioration detecting device using a normal circuit breaker for wiring.

[Explanation of symbols]

 1 Circuit breaker with a leakage breaker function 7 Switching contacts 8 Zero-phase current transformer 11 Leakage comparison output unit 21 Extraction unit 23 Comparison display unit C Insulation deterioration detection device

Claims (3)

[Claims] 1. A wiring breaker with an earth leakage breaking function, comprising: a switching contact which is interposed in a wiring and is opened in the event of an overload or a short circuit; and a zero-phase current transformer provided in the wiring. An insulation deterioration detecting device comprising: an extracting means for extracting the output of the phase current transformer; and a monitoring means connected to the extracting means for monitoring the output of the zero-phase current transformer. 2. A switching contact provided on the wiring and a zero-phase current transformer provided on the wiring, the switching being performed when the output of the zero-phase current transformer reaches a predetermined value. An earth leakage breaker that opens contacts and an output of the zero-phase current transformer, and outputs a warning with an output having a value lower than the output of the zero-phase current transformer that opens the switching contacts. An insulation deterioration detecting device comprising. 3. A wiring breaker, which is provided in the wiring and has a switching contact opened when an overload or a short circuit occurs, a zero-phase current transformer provided in the wiring at a stage subsequent to the switching contact, An insulation deterioration detecting device comprising a monitoring means for monitoring the output of a zero-phase current transformer.