JPH0759246A - Leak detection method - Google Patents

Abstract

PURPOSE:To specify a defective appliance efficiently while enhancing the workability. CONSTITUTION:In the leak detection method, a load circuit 57 having lowered insulation resistance is specified among a plurality of load circuits 57 by means of an insulation resistance meter. After opening the switch 54 for a specified load circuit 57, lead wires of different phases on the power supply side and the load side of the switch 54 are connected with detection lead wires 11A, 11B of a master unit 10 generating an alarm sound and delivering an alarm signal when the insulation resistance is lower than a predetermined value. A portable slave unit 30 receives the alarm signal to generate an alarm sound and an electric appliance is disconnected from a specified load circuit 57 thus specifying a defective appliance when the alarm sound is interrupted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leakage detecting method for detecting a leakage device from a low-voltage distribution circuit having a plurality of load circuits, and more particularly, to improve workability and efficiently identify a defective device. The present invention relates to a leak detection method.

[0002]

2. Description of the Related Art As a conventional leakage detection method, for example, there is a method of using a distribution line of a load circuit for detecting leakage as a communication line. This leakage detection method, the main unit measures the insulation resistance to ground of the load circuit, injects the signal output when the value is below a predetermined level into the distribution line of the load circuit,
The slave unit has a configuration to receive the injected signal via the current transformer. When the worker carrying the child device removes an electric device, which is considered to be a defective device, from the outlet, the ground insulation resistance is restored to a predetermined value. The signal indicating this recovery is also communicated to the slave unit via the distribution line of the load circuit.

[0003]

However, according to the conventional leakage detection method, since the output signal from the master unit is received by the current transformer from the distribution line, the behavior of the worker carrying the slave unit is reduced. The range is limited, or it becomes impossible for the worker to carry the child device. As a result, the workability of attaching or detaching electrical equipment to or from the outlet is reduced, and defective equipment can be efficiently identified. There is an inconvenience that you cannot do it.

Therefore, an object of the present invention is to provide an earth leakage detecting method capable of improving workability and efficiently identifying a defective device.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention isolates a load circuit from a plurality of load circuits by an insulation resistance meter in order to improve workability and efficiently identify defective equipment. After identifying the load circuit whose resistance has decreased and opening the switch of the specified load circuit, the lead wire of the different phase on the power supply side and the load side of the switch may cause a failure of the electrical equipment connected to the specified load circuit. Based on the lowering of insulation resistance, the detection lead wire of the main unit of the leakage detector that generates the alarm sound and transmits the alarm signal is connected, and the slave unit of the leakage detector that receives the alarm signal and generates the alarm sound is carried. However, the present invention provides a method for detecting electrical leakage by disconnecting an electric device from the specified load circuit and specifying the electric device as a defective device when the generation of the alarm sound is stopped.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The leakage detecting method of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an external view of a base unit 10 of an earth leakage detector applied to one embodiment of the present invention. The master device 10 includes lead wires 11A and 11B having grip terminals.
It has a detection cable 11 connected to a load circuit whose insulation resistance is reduced via a power supply switch 12 for adjusting the volume of an alarm sound, and a power supply lamp 13 for displaying the ON / OFF state of the power supply. .

As shown in FIG. 2, the circuit configuration of the base unit 10 includes a detection circuit 14 for detecting the insulation resistance value (ground) of the load circuit to which the detection cable 11 is connected, and a load circuit detected by the detection circuit 14. Low-frequency oscillator 15 that oscillates a low-frequency signal of a predetermined frequency when the insulation resistance value of is less than a predetermined level (100 ± 5 KΩ), and a low-frequency oscillator 15
When the low frequency signal is oscillated from the high frequency oscillator 16, which oscillates a high frequency signal of a predetermined frequency, and the low frequency oscillator 1
Low-frequency amplifier 1 for amplifying the low-frequency signal output from 5
7, a speaker 19 for outputting the amplified low frequency signal as an alarm sound, a modulation circuit 23 for FM-modulating the high frequency signal output from the high frequency oscillator 16, and a high frequency amplifier 24 for amplifying the high frequency signal of the FM modulated wave, Antenna 25 that transmits the amplified FM modulated signal as a transmission signal, power supply 20 that operates each circuit, and detection cable 11 as a voltage for measuring the insulation resistance value by boosting the voltage of 3 V of power supply 20 to 12 V. Boost converter 21
And a stabilizing circuit 22 for supplying a stabilized voltage to the modulating circuit 23 and the high frequency amplifier 24.

FIG. 3 shows the external appearance of the child device 30 of the leakage detector applied to one embodiment of the present invention. This slave unit 30 includes a volume 31 with a power switch capable of adjusting the volume of an alarm sound, an antenna connection section 32 to which an auxiliary antenna (described later) is connected if necessary, and a reception state displaying a reception state from the master unit 10. It has a lamp 33 and a power supply lamp 34 for displaying the ON / OFF state of the power supply.

As shown in FIG. 4, the circuit configuration of the handset unit 30 is such that an antenna 35 for receiving a transmission signal transmitted from the base unit 10 and a reception signal of a predetermined level or lower received by the antenna unit 35 are cut off. A limiter 36 for removing noise,
A high-frequency amplifier 37 for amplifying the received signal, a demodulation circuit 38 for extracting the signal from the FM modulated wave by mixing the amplified received signal and a local oscillation output from a local oscillator (not shown) and detecting the mixture. It is composed of a low-frequency amplifier 39 that amplifies the extracted signal, a speaker 41 that outputs the amplified signal as an alarm sound, and a power supply 42 that supplies power to each circuit via a stabilizing circuit 43.

The leakage detecting method of the present invention will be described below with reference to FIGS. 5 and 6. First, as shown in FIG. 5, the circuit breaker (SB) 51 and the earth leakage breaker (ELB) 5
Low-voltage service wire 53 having two and one phase composed of a ground conductor
In addition, the load resistance 57 whose insulation resistance has decreased is identified from among the plurality of load circuits 57 connected via the plurality of switches (MCCB) 54 using the insulation resistance meter 58.

Next, the switch 54 of the specified load circuit 57
6, the lead wires 11A and 11B of the detection cable 11 of the parent device 10 are connected to the conductors of different phases on the power source side and the load side of the switch 54, respectively, as shown in FIG.

After that, the volume 12 with the power switch of the base unit 10 is adjusted, and power is supplied from the power source 20 to each circuit to operate the base unit 10. Since the load circuit 57 to which the parent device 10 is connected has the ground insulation resistance lowered due to the presence of the leakage device, the low frequency signal and the high frequency signal are output from the low frequency oscillator 15 and the high frequency oscillator 16, respectively. Therefore, the alarm sound is output from the speaker 19 and the alarm signal is transmitted from the antenna 25 at the same time.

On the other hand, when the volume 31 with the power switch of the slave unit 30 is adjusted and the slave unit 30 is operated in the same manner, the transmission signal transmitted from the master unit 10 is received via the antenna 35 and an alarm is issued from the speaker 41. Sound is output.

When the leakage detector is operated in this manner, the worker carries the slave unit 30 and, as shown in FIG. 6, from the plurality of outlets 55 connected to the load circuit 57, the power cord 56 of the electric device. Remove. At this time, the handset 30
When the audible alarm generated from is stopped, it indicates that the insulation resistance of the load circuit 57 has been restored, so that the electrical device is specified as a defective device (electrical device with leakage).

As can be seen from the above-described embodiments, the worker can carry out the work of removing the power cord 56 of the electric device from the outlet 55 while carrying the child device 30, so that the workability is improved and the leakage device can be identified efficiently. Can be done on a regular basis.

[0017]

As described above, according to the leakage detection method of the present invention, a load circuit having a reduced insulation resistance is specified from among a plurality of load circuits by an insulation resistance meter, and a switch of the specified load circuit is identified. After opening, the different phase lead wires on the power supply side and the load side of the switch generate an alarm sound and transmit an alarm signal due to a decrease in insulation resistance due to a defect in the electrical equipment connected to the specified load circuit. Connect the detection lead wire of the main unit of the detector and receive the alarm signal and generate an alarm sound. While carrying the slave unit of the earth leakage detector, disconnect the electrical equipment from the specified load circuit and generate the alarm sound. Since the electric device at the time of stopping is identified as the defective device, the workability can be improved and the defective device can be efficiently identified.

[Brief description of drawings]

FIG. 1 is an external view showing a master unit of an earth leakage detector applied to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a master unit.

FIG. 3 is an external view showing a child device of an earth leakage detector applied to one embodiment of the present invention.

FIG. 4 is a block diagram showing a circuit configuration of a child device.

FIG. 5 is an explanatory diagram showing a low voltage distribution circuit according to an embodiment.

FIG. 6 is an explanatory diagram showing a usage state of the leakage detector according to the embodiment.

[Explanation of symbols]

10 Parent Device 11 Detection Cable 11A, 11B Lead Wire 12 Power Switch Volume 13 Power Lamp 14 Detection Circuit 15 Low Frequency Oscillator 16 High Frequency Oscillator 17 Low Frequency Amplifier 18 Transformer 19 Speaker 20 Power Supply 21 Boost Converter 22 Stabilization Circuit 23 Modulation Circuit 24 High frequency amplifier 25 Antenna 30 Handset 31 Volume switch with power switch 32 Antenna connection section 33 Receiving lamp 34 Power lamp 35 Antenna 36 Limiter 37 High frequency amplifier 38 Demodulation circuit 39 Low frequency amplifier 40 Transformer 41 Speaker 42 Power supply 43 Stabilization circuit 51 Circuit breaker 52 Leakage breaker 53 Low-voltage service wire 54 Switchgear 55 Outlet 56 Electrical equipment power cord 57 Load circuit 58 Insulation resistance meter

Claims (1)

[Claims] 1. A leakage detection method for detecting a leakage device from a low-voltage distribution circuit having a switch on each power supply side of a plurality of load circuits, wherein an insulation resistance meter reduces insulation resistance from the plurality of load circuits. Specified load circuit, after opening the switch of the specified load circuit, the power supply side of the switch and the lead wire of the different phase on the load side, defective electrical equipment connected to the specified load circuit Of the leakage detector that generates an alarm sound and transmits an alarm signal due to a decrease in insulation resistance based on the A method for detecting electrical leakage, characterized in that while the portable device is carried, the electric device is disconnected from the specified load circuit, and the electric device when the generation of the alarm sound is stopped is specified as a defective device.