JP2002354656A - Method of detecting leak circuit and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus that can reliably and quickly detect a leak when intermittent leaks occur in multiple branch circuits provided with a branch breaker only on a single pole. SOLUTION: Zero-phase current Io flowing in a trunk wiring 100 and load current IL1 (or IL2, IL3, etc.), flowing through a wire on one pole of the branch wiring 200 are severally detected by a zero-phase current detecting means and a load current detecting means. The vector quantities of change in current of the zero-phase current and the load current are compared by a vector comparing means 11. The leak circuit in multiple branch circuits are screened based on the results of the comparison so that an intermittent leak condition, where leaks occur and are recovered repeatedly, can be detected as a change in the vector quantity and the leak circuit of an intermittent leak can be specified reliably and quickly out of the multiple branch circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth leakage circuit detection device for detecting an earth leakage circuit in a branch circuit branched into a plurality of branches from a trunk line, and particularly to a case where a branch breaker is provided only on one pole side of a branch circuit. The present invention relates to an earth leakage circuit detection device that detects an earth leakage circuit. In recent years, in distribution boards such as apartment houses and buildings requiring many load circuits, there is a tendency to use a space-saving single-pole circuit breaker in a branch circuit to increase the capacity of the distribution board. .

[0002]

2. Description of the Related Art Hitherto, as this kind of leakage circuit detecting device, there has been one disclosed in Japanese Utility Model Laid-Open No. 5-45578 and Japanese Patent Publication No. 2-16097. This is shown in FIGS.
FIG. 8 is an overall circuit diagram of a conventional leakage circuit detection device represented by a single-line diagram, and FIG. 9 is an overall circuit diagram of another leakage circuit detection device.

[0003] In FIG. 8, a conventional earth leakage circuit detecting device includes a main line 100 of an electric circuit and the main line 100.
A zero-phase current transformer 2 and a zero-phase current transformer 30 for branching, which are provided in each branch wiring 200 branched from the main line 100 and detect a leakage current of the main wiring 100 and the respective branch wirings 200; A receiving circuit 400 that outputs an alarm signal when a leakage current detection signal output from the current transformers 2 and 30 is input; and a receiving circuit 400 that is connected between the respective zero-phase current transformers 2 and the receiving circuit 400. A switch 401 for switching and connecting the respective zero-phase current transformers 2 and 30 to the receiving circuit 400, and a leakage current detection signal is output from the zero-phase current transformers 2 and 30 of the main line 100. When the alarm signal is output, the alarm signal is stored in the temporary storage circuit 402, and then the switching control of each of the switches 401 is started, and the switching of the respective branch wirings 200 is started. The use zero-phase current transformer 30, sequentially, a switch control circuit 404 to be connected to the receiving circuit 400,
When an alarm signal is output from the receiving circuit 400 during the switching control process of the switch 401 by the switch control circuit 404, the branch wiring 200 of the zero-phase current transformer 30 for branching connected to the switch 401 is identifiably displayed. And a display circuit 403 to be provided.

According to the leakage circuit detection device having the above-described configuration, when a leakage current detection signal is output from the zero-phase current transformer 2 of the main line 100 and an alarm signal is output from the reception circuit 400, the switch control circuit 404 After the alarm signal is temporarily stored, each switch switching control is started, and the zero-phase current transformer 30 for branching of each branch wiring 200 is changed to
The connection is sequentially made to the reception circuit 400. When an alarm signal is output from the receiving circuit 400 during the switching control of the switch 401 by the switch control circuit 404,
Since a leakage current is flowing through the branch wiring 200 provided with the branch zero-phase current transformer 30 connected to the switch 401, the display circuit 403 displays the branch wiring 200 so that the branch wiring 200 can be identified.

[0005] In FIG. 9, another conventional earth leakage circuit detecting device is disposed on the surface of the distribution board corresponding to the position of the main earth leakage breaker 110 provided on the main line 100 and the branch breakers 210. An energization / leakage indicator light 501, an energization detection circuit 502 disposed on each branch wiring 200, a leakage detection circuit 503 disposed on each branch wiring 200, and The second switching circuit 505 that receives the detection signal of the conduction detection circuit 502, drives the conduction / leakage display lamp 501 to perform the leakage display, and turns off the first switching circuit 504.
And the power supply / leakage indicator lamp 501 and the power supply detection circuit 5
02 and a power supply circuit 5 for supplying drive power to the leakage detection circuit
06 and an electric leakage lighting resetting means 507 for resetting the electric leakage lighting state of the energization / electric leakage indicating lamp 501. Accordingly, an indicator light that is used for both the energization display and the earth leakage display of the multi-branch wiring 200 is provided on the power distribution display surface, so that the earth leakage branch wiring 200 can be easily determined even after the trip operation of the main earth leakage breaker.

[0006]

Since the conventional earth leakage circuit detecting device is constructed as described above, in the earth leakage circuit detecting device shown in FIG. 8, a branch breaker is arranged in a two-pole circuit. Since the zero-phase current transformers 2 and 30 are collectively clamped on a pair of two-pole electrodes forming each branch circuit in the distribution board, it is necessary to detect the zero-phase current of each branch circuit. There is a problem that a zero-phase current transformer, which is more expensive than a current transformer for detecting a general load current of all circuits, is required.

[0007] The earth leakage circuit detecting device shown in FIG.
Since the branch breaker is disposed on the two-pole electrodes forming the pair of the branch circuits, the zero-phase current transformer 2 can be clamped to the current forming the two-pole pair. In a plurality of branch circuits in which only a single-pole circuit is provided with a branch breaker as in the circuit detection device, there is a problem in that the two poles of the branch circuit cannot be collectively clamped and a leakage circuit cannot be specified.

Further, each of the above-mentioned conventional earth leakage circuit detection devices cannot accurately specify the earth leakage circuit in a plurality of branch circuits in the case of intermittent earth leakage in which the occurrence and recovery of the earth leakage are repeated, and the Since the detection work is performed in response to the experience and intuition of the user, a large amount of labor and work time are required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and when an intermittent leakage occurs in a plurality of branch circuits in which branch breakers are provided only in a single pole, the leakage circuit is detected reliably and quickly. It is an object of the present invention to provide an earth leakage circuit detection method and an earth leakage circuit device that can perform the method.

[0010]

According to the present invention, there is provided a method for detecting an earth leakage circuit, wherein a main earth leakage breaker is installed on a trunk line, the main earth leakage breaker is branched into a plurality of parts, and each pole on the branched branch line is provided. A branch breaker is interposed in the electric wire on the side, and each of the branched other wires and the unipolar wire in which the branch breaker is interposed are connected to a load. In the circuit detection method, a zero-phase current of the main line is detected, each load current of the single-pole-side electric wire is detected, and the detected zero-phase current and each load current are converted into a vector amount of each change current. Are compared with each other, and a single-pole-side electric wire through which the load current, in which the vector amount of the change current matches, is detected as an earth leakage circuit.

As described above, according to the present invention, the zero-phase current flowing through the main line and the load current flowing through the one-pole-side electric wire of the branch line are detected, and the vector amount of the current corresponding to the change between the zero-phase current and the load current is detected. Are compared, and based on the result of the comparison, a leakage circuit in a plurality of branch circuits is detected.
An intermittent leakage state in which the occurrence and recovery of the leakage are repeated can be detected as a change amount of the vector quantity, and the leakage circuit of the intermittent leakage can be reliably and quickly identified from the plurality of branch circuits.

Further, according to the leakage circuit detection method of the present invention, if necessary, the zero-phase current and the load current to be detected are each 1
The cycle is detected as multiple sampling data,
The sampled data of the detected zero-phase current and the sampled data of each load-side current are compared every cycle. As described above, in the present invention, the zero-phase current of the main line and the load current of the branch line are detected by predetermined sampling, and are compared every cycle based on the respective sampled data. The change of the vector amount of the change current can be easily detected by the change pattern of (1), and the leakage circuit of the intermittent leakage can be specified more quickly and accurately.

In the earth leakage circuit detecting apparatus according to the present invention, a main earth leakage breaker is installed in a trunk line, the main earth leakage breaker is branched into a plurality of stages, and a branch breaker is connected to each one-pole side electric wire in the branched branch line. In the earth leakage circuit detection device that detects the earth leakage of a circuit in which each of the branched electric wires on the other pole side and each of the unipolar electric wires on which the branch breaker is interposed are connected to a load. A zero-phase current detecting means for detecting a zero-phase current of the main line, a load current detecting means for detecting each load current of the one-pole electric wire, and changing each of the detected zero-phase current and each load current. Vector amount comparing means for comparing each of the vector amounts of the divided currents, and earth leakage circuit selecting means for selecting, as an earth leakage circuit, a single-pole-side electric wire through which the load current that matches the vector amount of the change current is matched. .

As described above, according to the present invention, the zero-phase current flowing through the main line and the load current flowing through the one-side electric wire of the branch line are detected by the zero-phase current detecting means and the load current detecting means, respectively.
The vector amount of each change current between the zero-phase current and the load current is compared by vector amount comparing means, and the leakage circuits in the plurality of branch circuits are selected by the leakage circuit selection means based on the comparison result. Therefore, it is possible to detect an intermittent leakage state in which the occurrence and restoration of the leakage are repeated as a change amount of the vector amount, and it is possible to reliably and quickly specify the leakage circuit of the intermittent leakage from the plurality of branch circuits.

Further, in the earth leakage circuit detection device according to the present invention, the zero-phase current detection means detects the zero-phase current as a plurality of sampling data for one cycle as necessary, and the load current detection means detects each load current. One cycle is detected as a plurality of sampling data, and the vector amount detecting means compares the detected sampling data of the zero-phase current with the sampling data of each load-side current for each cycle.

As described above, in the present invention, the zero-sequence current of the main line and the load current of the branch line are detected by the zero-sequence current detection means and the load current detection means at a predetermined sampling, and one-phase current is detected based on each sampling data. Since the vector amount comparison means performs comparison for each cycle, it is possible to easily detect the change in the vector amount of the change current in the change pattern of each sampling data, and more quickly and accurately specify the leakage circuit of the intermittent leakage. it can.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment of the Present Invention) Hereinafter, an earth leakage circuit detecting apparatus according to a first embodiment of the present invention will be described together with a method thereof with reference to FIGS. FIG. 1 is an overall schematic configuration diagram of the leakage circuit detection device according to the present embodiment, and FIG. 2 is an operation explanatory diagram of the leakage circuit detection device shown in FIG.

In each of the drawings, the earth leakage circuit detecting apparatus according to the present embodiment is a mains zero-phase current transformer (hereinafter, ZCT) for detecting a zero-phase current Io of the main wiring 100 in which the main earth leakage breaker 110 is disposed. 2 and, on the power application side (non-ground side) of the two-pole branch wiring 200 that is branched into a plurality of stages after the main earth leakage breaker 110 provided on the main wiring 100, the branch breaker 210 is provided. The branch current transformer 3 for detecting the load currents IL1, IL2, IL3,... Flowing through the branch single line 201, the zero-phase current Io and the load currents IL1, IL
., IL3,... As a vector quantity, and a load current IL1 based on the comparison result.
(Or IL2, IL3,...) Through which the single-line branch 201 flows is selected as a leakage circuit. The apparatus main body 1 is composed of the vector comparing means 11 and the earth leakage circuit selecting means 12.

In the branch wiring 200 branched from the main wiring 100, a branch breaker 210 is provided for each branch single line 201 on the power receiving side, and each branch single line 2 on the ground side.
02 is commonly connected via a copper bar 203. Each branch single line 201 on the power application side and each branch single line 202 on the ground side are connected to the load 300 as a pair of two-pole lines. The vector comparing means 11 determines whether the load current IL1 of the branch single line 201 on the power-supply side is a zero-phase current Io + Ig on which the leakage current Ig generated when a ground fault occurs is superimposed.
(Or IL2, IL3,...) + Ig as a vector amount of a change current.

Next, the operation of the earth leakage circuit detecting apparatus according to the present embodiment based on the above configuration for detecting an earth leakage circuit will be described. As a premise, it is assumed that an intermittent ground fault has occurred in each of the branch single lines 201 on the power supply side among the plurality of branch wirings 200. The ground fault current Ig generated by the ground fault accident flows through the main line 100, and the main ground fault breaker 110 trips due to the ground fault current Ig to cut off the main line 100. Since the ground fault accident is intermittent, when the main earth leakage breaker 110 is turned on, the entire circuit is temporarily restored, but after a predetermined period, the earth leakage current Ig flows again, and the main earth leakage breaker 110 operates again. When such an intermittent ground fault occurs, first, the main earth leakage breaker 110 is turned on to restore the entire circuit, and each branch wiring 20
0 to supply current to the load 300. The ZCT 2 is clamped to the main line 100 in the live state, and the branch current transformer 3 is clamped to each branch line 200.

In this clamped state, the vector comparison means 11 continuously compares the outputs of the ZCT 2 and the branch current transformer 3 as vector quantities. If the intermittent ground fault reoccurs during this comparison operation, the vector comparison means 11 detects a coincidence only in the component of the leakage current Ig superimposed on each output of the ZCT 2 and the branch current transformer 3. That is, the zero-phase current Io output from the ZCT 2 and the load currents IL1, IL2, IL3 output from the branch current transformer 3 constantly fluctuate due to the load 300, and the distribution of the main wiring 100 and the branch wiring 200. Since the leakage current as a constant is constantly present, the detection current (Io + Ig) by the ZCT 2 and the detection current (I
L1 + Ig, or IL2 + Ig, IL3 + Ig,...) Must be detected as a vector amount only. The branch wiring 20 in which the coincidence of the leakage current Ig is detected
0 is connected to the vector comparing means 11
Is selected from the plurality of branch single lines 201 on the power receiving side and specified as a leakage circuit in which a ground fault has occurred.

(Second Embodiment of the Present Invention) FIG. 3 is a detailed block diagram of a main part of an earth leakage circuit detecting apparatus according to a second embodiment of the present invention, and FIG. 4 is a block diagram of a sampling control unit shown in FIG. FIG. 5 is an explanatory diagram of a storage operation in the memory control unit shown in FIG. 3, FIG. 6 is an explanatory diagram of a comparison operation in the comparison unit shown in FIG. 3, and FIG. 7 is sampling data in the comparison unit shown in FIG. FIG.

In each of the drawings, the earth leakage circuit detecting apparatus according to the present embodiment comprises a ZCT 2, a branch current transformer 3, a vector comparing means 11 and an earth leakage circuit selecting means as in the first embodiment shown in FIG. 12 in common, the configuration of the vector comparison means 11 is different, and in addition to this configuration, the memory 4 for storing various data and the earth leakage circuit selection means 12
And a display device 5 for displaying the contents of the selection by the display device.

The vector comparison means 11 calculates the ZCT
, An amplifier 11a for amplifying the zero-phase current Io and the load currents IL1, IL2, IL3,... Detected by the current transformer 2 and the branch current transformer 3, respectively, and the amplified zero-phase current Io and each load current IL1, A / D converter 11b for converting analog values of IL2, IL3,... Into digital values, zero-phase current Io of the converted digital values and load currents IL1, I2
.. As sampling data, a memory control unit 11d for sequentially storing the sampling data in the memory 4, and a sampling control unit 11d for sequentially storing the sampling data in the memory 4. This is a configuration including a comparison unit 11e that compares sampling data. The comparing unit 11e compares the sampling data before and after sequentially stored in the memory 4 to compare the leakage current I
g is extracted as a difference, and the extracted leakage current Ig is used as the zero-phase current Io and each of the load currents IL1, IL2, I2.
L3,... Are compared.

Next, a description will be given of an operation of detecting a leakage circuit of the leakage circuit detection apparatus according to the present embodiment based on the above configuration. ZCT clamped as in the first embodiment
2 and the load currents IL1, IL2, IL3,... (In the event of a ground fault, zero-phase currents Io + Ig and IL1 + Ig, IL1 + Ig, IL2 + Ig, IL
3 + Ig,...) Are output as detection currents, and each of these detection currents is amplified by the amplifier 11a and further converted to a digital value by the A / D converter 11b.

The sampling data of each detected current generated by the A / D converter 11b is sampled by the sampling value of the sampling control section 11c and output from the A / D converter 11b to the memory 4 as sampling data. The sampling control unit 11c divides one cycle of the alternating current as a sampling value into a plurality of equal intervals, for example, divides one cycle into 64 equal parts (shown in FIG. 4) or 12.
The interval can be set to be equally divided into eight. Each sampling data of the detected current is stored in the buffer memory 41 as one cycle of table data under the control of the memory control unit 11d as shown in FIG. In addition,
When the cycle data is generated by the A / D converter 11b, each table data for one cycle before the data stored in the buffer memory 42 is copied and stored in the buffer memory 41.

The comparison unit 11e compares the table data stored in the buffer memories 41 and 42 before and after each cycle, and determines the coincidence of the variation for each angle during one cycle. As shown in FIG. 6, comparison as a vector amount is possible. In FIG. 6, when an intermittent leakage fault occurs in one of the branch single lines 201 on the power receiving side, a leakage current Ig occurs after the occurrence of the leakage fault (see FIG. 6A). This leakage current Ig is superimposed on the zero-phase current Io and the load current IL1 (or IL2, IL3,...) (See FIGS. 6B to 6E) and detected by the ZCT 2 and the branch current transformer 3. Current is zero-phase current + leakage current (Io + Ig)
And a load current + leakage current (IL1 + Ig) is detected as a detection current.

As described above, when the comparator 11e compares the leakage current Ig included in each detected current before and after each cycle and detects a change, the change can be extracted as a component of the leakage current Ig. Become. Further, in FIG. 7, a difference table between N and N−1 of ZCT is extracted.
Similarly, each is compared with the difference tables of CT1 to CT3 in FIG. 7, and those having exactly the same data are determined as the leakage circuit. If this match is determined,
As in the case of the first embodiment, the earth leakage circuit selecting means 1
2 determines a leakage circuit from among the plurality of branch wirings 200 based on the comparison result.

[0029]

According to the present invention, the zero-phase current flowing through the main line and the load current flowing through the one-sided electric wire of the branch line are detected, and the vector amount of the current corresponding to the change between the zero-phase current and the load current is detected. Since the comparison is made and the leakage circuit in the plurality of branch circuits is detected based on the comparison result, an intermittent leakage state in which the occurrence and restoration of the leakage are repeated can be detected as a change amount of the vector amount, and the plurality of branch circuits can be detected. There is an effect that the leakage circuit of the intermittent leakage can be reliably and quickly identified from the circuit. In addition, a relatively expensive zero-phase current transformer is not used for each branch circuit, and an inexpensive current transformer can be used.

In the present invention, the zero-phase current of the main line and the load current of the branch line are detected by predetermined sampling, and are compared every cycle based on the respective sampling data. The change of the vector amount of the change current can be easily detected based on the change pattern of the sampling data, and there is an effect that the leakage circuit of the intermittent leakage can be more quickly and accurately specified.

In the present invention, the zero-phase current flowing through the main line and the load current flowing through the one-pole side of the branch line are detected by the zero-phase current detecting means and the load current detecting means, respectively. The vector amount of each change current is compared by the vector amount comparison means, and the leakage circuits in the plurality of branch circuits are selected by the leakage circuit selection means based on the comparison result. Can be detected as the amount of change in the vector amount, and the leakage circuit of the intermittent leakage can be reliably and quickly specified from among a plurality of branch circuits.

In the present invention, the zero-phase current of the main line and the load current of the branch line are detected by the zero-phase current detecting means and the load current detecting means by predetermined sampling, and one cycle is performed based on each sampling data. Since the vector amount comparison means makes a comparison every time, it is possible to easily detect the transition of the vector amount of the change current in the change pattern of each sampling data, and it is possible to more quickly and accurately specify the leakage circuit of the intermittent leakage. This has the effect.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram of an earth leakage circuit detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of the earth leakage circuit detection device shown in FIG.

FIG. 3 is a detailed block diagram of a main part of an earth leakage circuit detection device according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a sampling operation in a sampling control unit shown in FIG. 3;

FIG. 5 is an explanatory diagram of a storage operation in the memory control unit shown in FIG. 3;

FIG. 6 is an explanatory diagram illustrating a comparison operation in the comparison unit illustrated in FIG. 3;

FIG. 7 is an explanatory diagram of comparison of sampling data in the comparison unit shown in FIG. 3;

FIG. 8 is an overall circuit diagram expressing a conventional earth leakage circuit detection device by a single-line diagram.

FIG. 9 is an overall circuit diagram of another conventional leakage circuit detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Device main body 2 Zero-phase current transformer (ZCT) 2 3 Branching current transformer 4 Memory 5 Display device 11 Vector comparison means 11a Amplifier 11b A / D converter 11c Sampling control unit 11d Memory control unit 11e Comparison unit 12 Earth leakage circuit selection Means 30 Zero-phase current transformer for branching 41, 42 Buffer memory 100 Main line 110 Main earth leakage breaker 200 Branch line 201 Each branch single line on the power application side 202 Each branch single line on the ground side 203 Copper bar 210 Branch breaker 300 Load 400 Receiving circuit 401 switch 402 storage circuit 403 display circuit 404 switch control circuit 501 energization / leakage indicator 502 energization detection circuit 503 leakage detection circuit 504 first switching circuit 505 second switching circuit 506 power supply circuit 507 leakage leakage lighting reset means

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[Procedure amendment]

[Submission date] April 4, 2002 (2002.4.4)

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Claims (4)

[Claims] 1. A main earth leakage breaker is installed on a main line, a plurality of branches are provided at a stage subsequent to the main earth leakage breaker, and a branch breaker is interposed in each one-pole-side electric wire in the branched branch line. In the earth leakage circuit detection method for detecting the earth leakage of a circuit in which each of the other-pole-side electric wires and each of the uni-pole-side electric wires having the branch breaker interposed are connected to a load, the zero-phase current of the main line is detected. Detecting each load current of the one-pole electric wire, comparing the detected zero-phase current and each load current with respect to the vector amount of each change current, the vector amounts of the change currents match. And detecting the one-sided electric wire through which the load current flows as a leakage circuit. 2. The leakage circuit detection method according to claim 1, wherein the detected zero-phase current and load current are each detected as a plurality of sampling data in one cycle, and the detected zero-phase current is sampled. A method of detecting an earth leakage circuit, wherein data is compared with sampling data of each load side current every cycle. 3. A main earth leakage breaker is installed on a main line, the main earth leakage breaker is branched into a plurality of parts at a subsequent stage, and a branch breaker is interposed in each one-pole-side electric wire in the branched branch line. In the earth leakage circuit detection device that detects the earth leakage of a circuit in which each of the other pole-side electric wires and each of the unipolar-side electric wires having the branch breaker interposed are connected to a load, the zero-phase current of the main line is detected. Zero-phase current detection means, load current detection means for detecting each load current of the one-pole-side electric wire, and comparing the detected zero-phase current and each load current with respect to a vector amount of each change current. A leakage circuit detection device, comprising: a vector amount comparison unit that performs the load current matching the vector amount of the change current; and a leakage circuit selection unit that selects a single-pole-side electric wire through which the load current flows as a leakage circuit. 4. The leakage circuit detection device according to claim 3, wherein the zero-phase current detection means detects the zero-phase current as a plurality of sampling data for one cycle, and the load current detection means detects each load current. An earth leakage circuit which detects a plurality of sampling data for one cycle, and wherein the vector amount detecting means compares the detected sampling data of the zero-phase current and the sampling data of each load-side current for each cycle. Detection device.