JPH04152272A - Current interruption detecting system - Google Patents

Abstract

PURPOSE:To enable only the interruption of feed current equal to or above the predetermined value to be detected by detecting induced voltage occurring across an induction coil laid at a feeder. CONSTITUTION:The induced voltage Vc of an induction coil 33 is inputted to the input terminal (-) of a comparator 346 after division into voltage Vc1. Also, reference voltage VTH set at the intermediate level of the predetermined value of the divided voltage Vc1, is inputted to the input terminal (+) of the comparator 346. When comparison voltage Vcp is low, a flipflop circuit 347 maintains reset state, and keeps the detected output di of an output terminal Q at a low level. When the comparison voltage Vcp is changed to a high level, the flipflop circuit 347 is turned to set state, and the detected output di is thereby turned to high level. Consequently, a detection circuit 34 sends the detected output di, only when feed current I2 equal to or above the predetermined value is interrupted with a circuit breaker 21, but does not send the output di, when feed current I below the predetermined value is interrupted.

Description

[Detailed Description of the Invention] [Summary] Regarding the current interruption detection method that detects the interruption of the power supply current supplied to the load via the current breaker, the current breaker can be selected as freely as possible, and the The purpose of this method is to realize a current interruption detection method that detects only when the power supply current flows and is interrupted, and can be electrically isolated from the current breaker and the power supply line. A guide wire ring is provided on the power supply line, and a voltage change detection means for detecting the induced voltage generated in the guide wire ring when the current breaker interrupts the power supply current exceeding a predetermined value is attached to each induction wire. A plurality of current circuit breakers are arranged in a matrix, and a plurality of current circuit breakers are arranged in a row and column to connect the load to the load through each current circuit breaker. Each feeder line that supplies power supply current is provided with a first guide wire ring and a second guide wire ring, and a voltage change detection means is provided corresponding to each row and each column. Each first induction wire corresponding to a current circuit breaker is connected in series, connected to a voltage change detection means provided corresponding to each row, and corresponding to each current circuit breaker arranged in the same column. Each of the second guide wires is connected in series and connected to a voltage change detection means provided corresponding to each column, and the voltage change detection means corresponding to each row is connected to an arbitrary current breaker corresponding to each row. The induced voltage generated in the corresponding first induction wire when the supply current exceeding a predetermined value is interrupted is
Detection through the other first guiding wheel connected in series,
The voltage change detection means corresponding to each column detects the induced voltage generated in the corresponding second induction wire when an arbitrary current breaker corresponding to each column interrupts a power supply current exceeding a predetermined value. is detected through the other second guide wire connected in series, and the interrupted power supply current is detected by the combination of the detection outputs of the voltage change detection means provided corresponding to each row and each column. Configure to detect.

[Industrial application field]

The present invention relates to a current interruption detection method for detecting interruption of a power supply current supplied to a load via a current breaker.

[Conventional technology]

FIG. 5 is a diagram showing an example of a power supply system to which the present invention is applied, FIG. 6 is a diagram showing an example of a conventional current interruption detection method, and FIG. 7 is a diagram showing an example of a fuse with an alarm contact. 8 is a diagram showing an example of another conventional current interruption detection method, FIG. 9 is a diagram showing an example of still another conventional current interruption detection method, and FIG. 10 is a diagram showing an example of another conventional current interruption detection method. 9 is a diagram showing an example of a detection output waveform in FIG. 9. FIG.

In FIG. 5, a main distribution board 2 is provided corresponding to a main power supply device 1 of the exchange, which is composed of, for example, a storage battery and a rectifier, and a plurality of racks 3 composing the exchange are arranged in a line. Row 4 (individual rows are referred to as 4-1 and 4-2, and each rack composing row 4-1 is referred to as 3-11 to 3-1)
3, hereinafter the same), respectively, the distribution board 5
is provided.

Power is supplied from the main power supply device 1 to the exchange. The power supply current I0 is the power supply! It is transmitted to the main distribution board 2 via a10, and the no-fuse breaker (NF
B) The power is divided into 4 units of overhead lines via 20 and supplied to each distribution panel 5 via feeder lines 11, respectively.

The power supply current 11 transmitted to each distribution board 5 is divided into three units of each rack via a no-fuse breaker (NFB) 21 provided corresponding to each rack 3, and is then routed through the feed lineman 2. and is supplied to each rack 3.

Each distribution board 5 is equipped with a current interruption detection device (DET).
30 is provided, and when an arbitrary no-fuse breaker (NFB) 21 provided in each distribution board 5 detects that the power supply current I has been cut off, the The detection output d is transmitted to the central control device 7.

Each central control device 7, which has received the detection output d, sends an alarm display indicating that the interruption of the power supply current I has occurred and identifying the rack 3 where the interruption has occurred, to the installation room of the switching equipment or the room where maintenance personnel are stationed. It is displayed on the provided alarm display device 6.

Note that since the detection output d output from each current interruption detection device (DET) 30 is transmitted to the duplex central control device 7, the power supply current 2 to either one of the central control devices 7 is interrupted. However, the alarm display device 6 reliably displays the alarm.

In one example of a conventional current interruption detection system, a no-fuse breaker (NFB) 21 equipped with an alarm contact 213 is used as shown in FIG.

In Figure 6, no fuse breaker (NFB) 21
The current cutoff contact 211 is set to the normal conduction state (the state shown in the figure), and the alarm contact 213 is set to the cutoff state, so that the power supply current I2 supplied via the power supply line 11 and divided to each rack 3 unit is is supplied to each rack 3 via the current cutoff contact 211, the electromagnet 212, and the power supply line 12.

In such a state, if a fault occurs in the rack 3 and a power supply current I exceeding a specified value flows to the electromagnet 212, the electromagnet 21
2 operates, setting the current cutoff contact 211 to the cutoff state and setting the alarm contact 213 to the conduction state.

As a result, the photocoupler 31 in the detection circuit 31 provided corresponding to each no-fuse breaker (NFB) 21
3 diode section 313. is from the power supply 311 to the resistor 31
2 and the alarm contact 213, the transistor section 3137 changes from a cutoff state to a conduction state, changing the input voltage vl of the inverter 315 from a high level to a low level.

As a result, the output voltage v0 of the inverter 315 changes from a low level to a high level, and is output as a detection output di.

The central control device 7 receives the detection output di output from the detection circuit 31 corresponding to each no-fuse breaker (NFB) 21 in the current interruption detection device (DET) 30, and operates the no-fuse breaker (NFB) 21. Supply current■
2 recognizes the blocked rack 3.

Note that instead of the no-fuse breaker (NFB) 21, a fuse 22 with an alarm contact as illustrated in FIG. 7 is used, and in place of the alarm contact 2I3 in FIG. 6, the fuse 22 with an alarm contact is provided. Even if the alarm contact 222 is used, the detection circuit 31 outputs the same detection output di.

Furthermore, a large number of no-fuse breakers (N
FB) 21 is provided, a detection circuit 31 is provided corresponding to each no-fuse breaker (NFB) 21, and each detection output di output from each detection circuit 31 is independently controlled by a central control device. Instead of transmitting to the 7th, the 8th
As illustrated in the figure, each no-fuse breaker (NFB)
21 are arranged in a matrix, and a detection circuit 31 is provided corresponding to each row and each column.
(however, i (=1 to N) indicates the row number), the detection circuit corresponding to each column is called 31y+ (however, j (=1 to M) indicates the column number), the same shall apply hereinafter], the same row and Each no fuse breaker (NFB) 21 arranged in the same row
1+ alarm contact 213 is connected via a diode D to a detection circuit 3 provided corresponding to each row and each column.
Connect in parallel to 1 and 31Y.

As a result, any no-fuse breaker (NFB) 21
When the power supply current I is cut off by operation of the no fuse breaker (NFB) 21, ., the row side detection circuit 31x1 and the column side detection circuit 317. are the detection output dXl and (Iy+
is output and transmitted to the central control device t7.

The central control device 7 receives the transmitted detection outputs dXl and d
Due to the combination of YI, the power supply current I2 is cut off at rack 3.
Detect.

Next, in the current interruption detection method illustrated in FIG. 9, a no-fuse breaker (NFB
) 21, the output voltage V to the power supply line 12 is monitored by the detection circuit 32 to detect interruption of the power supply current (2).

In FIG. 9, the output voltage V, is equal to the resistors 321 and 3
22 and input to the input terminal (-) of the comparator 326.

Note that the constant voltage diode 323 is for high voltage protection for the comparator 326.

The comparator 326 has a partial voltage v2 input to the input terminal (-).
is compared with the reference voltage V input to the input terminal (10), and when the divided voltage V2 exceeds the reference voltage V, the photocoupler 327 is energized in order to set the output voltage V to a low level. However, when the divided voltage V2 becomes lower than the reference voltage V, the output voltage Vs is set to a high level. To make the change, the photocoupler 327 is energized and sets the detection output di to a high level in a process similar to that in the detection circuit 31 (FIG. 6).

As described above, the central control device 7 receives the detection output di output from the detection circuit 32 corresponding to each no-fuse breaker (NFB) 21, and detects the no-fuse breaker (NFB).
FB) 21 operates to recognize the rack 3 from which the power supply current I2 has been cut off.

[Problem to be solved by the invention]

As is clear from the above explanation, in the conventional current interruption detection method, a no-fuse breaker (NFB) 21 with an alarm contact 213 is used, and the alarm contact 213
The conduction/cutoff state of the
and 31YI, the rack 3 where the power supply current I2 was cut off.
, or by using a no-fuse breaker (NFB) 21 without an alarm contact and monitoring the output voltage V1 to the power supply line 12 with the detection circuit 32, the rack 3 whose power supply current I is cut off can be detected. was detected.

First, a no fuse breaker (NFB) with alarm contact 213
) 21 has a limit on the withstand voltage of the alarm contact 213, and operates only when the power supply current I, which is higher than the specified value, flows and is cut off, and when the power supply current I2, which is lower than the specified value, is intentionally cut off. Depending on conditions such as selecting alarm contacts that do not operate,
The selection range of usable no-fuse breakers (NFB) 21 is limited, which poses a problem of impairing economic efficiency.

Also, no-fuse breaker (NFB) 2 without alarm contact
1, since the detection circuit 32 is directly connected to the power supply line 12, it is necessary to provide sufficient high voltage protection means (for example, the constant voltage diode 323 in FIG. 9) for the detection circuit 32, and the detection output A means to separate the output circuit of di from the power supply line 12 (photocoupler 327 in Fig. 9) is essential, which impairs the economic efficiency of the detection circuit 32, and also intentionally disconnects the power supply current (2) below the specified value. There is also a problem that there is a possibility that the detection output di will be output even in the case of the detection output di.

The present invention makes it possible to select a current breaker as freely as possible, detects only when a power supply current exceeding a specified value flows and interrupts the current, and further enables current interruption detection to be electrically separated from the current breaker and the power supply line. The purpose is to realize the method.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention; FIG. 1(a) shows the principle regarding the present invention (claim 1), and FIG. 1(b) shows the principle regarding the present invention (claim 2).

In FIGS. 1(a) and 1(b), 100 is a current breaker, and 200 is a power supply line.

Reference numeral 300 denotes a guide wire ring provided on the feeder line 200 according to the present invention (claim 1).

301 and 302 are a first guide wire ring and a second guide wire ring provided in the feeder line 200 according to the present invention (claim 2).

400 is a voltage change detection means provided according to the present invention (claims 1 and 2).

Note that the voltage change detection means 400 is provided corresponding to each guide wire ring 300 in the present invention (claim 1).

Further, in the present invention (claim 2), the plurality of current circuit breakers 100 are arranged in a matrix, and each first guide wire 301 corresponding to each current circuit breaker 100 arranged in the same row, and the same The second guide wires 302 corresponding to the current circuit breakers 100 arranged in the columns are connected in series, and the voltage change detection means 400 is provided corresponding to each row and column.

[Effect]

In claim 1, the voltage change detection means 400 detects the induced voltage generated in the guide wire 300 when the corresponding current breaker 100 interrupts a power supply current equal to or higher than a predetermined reference value, In claim 2, wherein the power supply current is interrupted by the detection output of the voltage change detection means 400, the voltage change detection means 400 corresponding to each row detects that any current breaker 100 corresponding to each row has a predetermined value or more. When the power supply current is cut off, the induced voltage generated in the corresponding first guide wire 300 is detected via the other first guide wire 301 connected in series, and The voltage change detection means 400 detects the induced voltage generated in the corresponding second induction coil 302 when any current breaker 100 corresponding to each row interrupts a supply current of a predetermined value or more. , through the other second guide wire 302 connected in series, and by a combination of the detection outputs of the voltage change detection means 400 provided corresponding to each row and each column, the interrupted power supply current is detected. Detect.

Therefore, there is no need to use a current breaker with an alarm contact, and there is no need to electrically connect the current breaker to the power supply line, and there is a current interruption detection method that can detect the interruption of only the power supply current exceeding a specified value. It becomes realizable.

〔Example〕

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

FIG. 2 is a diagram showing a current interruption detection method according to an embodiment of the present invention (claim 1), FIG. 3 is a diagram showing an example of the detection output waveform in FIG. 2, and FIG. 4 is a diagram showing an example of the detection output waveform in FIG. It is a figure which shows the current interruption detection method by one Example of invention (Claim 2). Note that the same reference numerals indicate the same objects throughout the figures.

The target power supply system is as shown in FIG.

First, one embodiment of the present invention (claim 1) will be described using FIGS. 2 and 3.

In FIG. 2, the current breaker 10 in FIG.
A no-fuse breaker (NFB) 21 is shown as 0, a power feed line 12 is shown as the power feed line 200 in FIG.
A guide wire ring 33 is provided as the voltage change detection means 400 in FIG. 1, and a detection circuit 34 is provided as the voltage change detection means 400 in FIG.

In Figures 2 and 3, no fuse breakers (
The current cutoff contact 211 of the NFB) 21 is normally set to a conductive state (the state shown in the figure), and the current cutoff contact 211 is supplied via the power supply line 11 and diverts the divided power supply current I2 to the current cutoff contact 211.
The power is supplied to each rack 3 via the electromagnet 212 and the power supply line 12.

The induction wire ring 33 outputs an induced voltage vc according to a change in the power supply current (2) flowing through the power supply line 12, and transmits it to the detection circuit 34.

In the detection circuit 34, the induced voltage Vc is divided by resistors 341 and 342, and the comparator 3
It is input to the input terminal (-) of 46.

Note that the capacitor 343 constitutes a noise filter together with the resistor 342, and removes high frequency noise from the induced voltage Vc.

The input terminal (+) of the comparator 346 receives a reference voltage V?, which is set by dividing the power supply 311 by resistors 344 and 345. H is input.

The comparator 346 has a divided voltage VC input to the input terminal (-).
I is compared with the reference voltage V7H input to the input terminal (+), and when the divided voltage VC0 is lower than the reference voltage VTH, the comparison voltage V is output. , is maintained at a low level, but when the divided voltage VCI exceeds the reference voltage ytH, the output comparison voltage VCP is changed from a low level to a high level.

The comparison voltage Ver is applied to the set input terminal (S
) and the comparison voltage V. While P is maintained at a low level, the flip-flop (FF) 347 maintains the reset state and maintains the detection output di output from the output terminal (Q) at a low level, but when the comparison voltage Vcp is low. When the setting is changed from the level to the high level, the flip-flop (FF) 347 is kept set and the detection output di output from the output terminal (Q) is changed from the low level to the high level.

When a power supply current (■) lower than the specified value is supplied to the rack 3, and when such power supply current I2 is intentionally cut off, there is a problem in the rack 3 compared to the induced voltage VC generated in the guide wire ring 33. occurs and a power supply current I exceeding the specified value is supplied, so when the no-fuse breaker (NFB) 21 operates and cuts off the power supply current I2, the induced voltage Vo generated in the induction wire 33 becomes higher. voltage.

Therefore, if the reference voltage V7H is set to the supply current I below the specified value,
A partial voltage Vc1 corresponding to the current, and a partial voltage V corresponding to the power supply current exceeding the specified value. 1, the detection circuit 34 outputs the detection output di only when the power supply current I, which is equal to or greater than the specified value, is interrupted by the no-fuse breaker (NFB) 21, and when the supply current I, which is equal to or greater than the specified value, is If the power supply current I is cut off, the detection output di will not be output.

The central control device 7 controls each no-fuse breaker (NFB)
21 and the detection output di output from the detection circuit 34 corresponding to the feeder line 12, and the no fuse breaker (
NFB) 21 operates to recognize the rack 3 to which the power supply current I has been cut off.

When the recognition of the rack 3 is completed, the input voltage of the reset input terminal (R) of the flip-flop (FF) 347 is changed from a low level to a high level by operating a changeover switch 348 provided in the detection circuit 34. , the flip-flop (FF) 347 enters a reset state, and the detection output di currently being output from the output terminal (Q) returns to a low level.

Next, one embodiment of the present invention (claim 2) will be described using FIG. 4.

In FIG. 4, each current circuit breaker 100 arranged in a matrix in FIG. =1 to M) indicate column numbers], and each feed line 12. is shown as each feed line 200 in FIG. 1(b), and each first feed line in FIG. A row-side guide ring 33□1 is provided as a guide ring 30], and a row-side guide ring 33Y is provided as each second guide ring 302 in the first output).
Further, as each voltage change detection means 400 in FIG. 1(b), a detection circuit 34□ is provided on the row side, and a detection circuit 34V1 is provided on the column side.

In addition, each no fuse breaker (NF B) 21 +7
The detection circuits 34.1 and 34Y1 have the same configuration as shown in FIG. 2, respectively.

The row-side guide wire wheels 33.1 arranged in the -i row are connected in series with each other and connected to the corresponding detection circuits 34x1, and each column-side guide wire ring 33.1 arranged in the -j column is , are connected in series with each other and connected to the corresponding detection circuit 34Y.

Each row side guide wire ring 33fI and column side guide wire ring 33YIJ
Second, the corresponding no-fuse breaker (NFB) 21□
And due to changes in the feed current ■2 flowing through the feed line 121J, the induced voltage VC similar to that of the induction wire 33 in FIG.
occur respectively.

Therefore, the induced voltage vc generated in each of the series-connected row-side guide wheels 33xl is added and inputted to the row-side detection circuit 34x1, and the column-side detection circuit 34YJ is
The induced voltages Vc generated in the series-connected column-side guiding wire wheels 33Y□ are added and input.

Here, the reference voltages V and N of the detection circuit 34□ on each row side are
When each feed current I is maintained below a specified value or is intentionally cut off, a partial voltage V corresponding to the sum of induced voltages Vc generated in each row-side guiding coil 33x is higher than C1, and When any power supply current I2 increases above the specified value and the corresponding no-fuse breaker (NFB) 21° cuts off the power supply current I2, the corresponding row-side guide wire 33□
The reference voltage VT of the detection circuit 34Y on each column side is set lower than the partial voltage VC1 corresponding to the induced voltage VC generated in the VC, and each supply current I is maintained below a specified value.
Or, if the guide wire ring 33 on each row side is cut off intentionally,
The induced voltage V generated at 71. The partial pressure v corresponding to the added value of
No fuse breaker (NFB) 21 that is higher than cI and corresponds to an arbitrary power supply current ■2 that increases above the specified value
．． 1 is lower than the partial voltage VCI corresponding to the induced voltage vc generated in the corresponding row-side induction coil 33y+ when the supply current ■2 is cut off (if set, a failure occurs in any rack 3) and a no-fuse breaker (NFB) 2t arranged in the corresponding i-th row and j-th column, and a power supply line 121.
As a result of the power supply current passing through ■2 increasing to more than the specified value,
Assuming that the no-fuse breakers (NFB) 21, , operate to cut off the power supply current ■2, the induced voltage VC generated in the corresponding row-side guide coil 33x□ and column-side guide coil 33V1 will be the same as that of the i-row. are input to the detection circuit 34 and the j-column detection circuit 31Y, and in the same process as in FIGS. 2 and 3, the detection outputs d□ and d Yl are respectively
is output and transmitted to the central control device 7.

The central control device 7 detects the rack 3 from which the power supply current I11 has been cut off, based on the combination of the transmitted detection outputs d x+ and d Yl.

As is clear from the above description, according to the embodiment shown in FIG. It can be used, and without electrically connecting to the no-fuse breaker (NFB) 21 and the power supply line 12, the power supply current exceeds the specified value ■2
Only when the rack 3 is cut off, the detection output di is outputted and transmitted to the central control device 7, and it becomes possible to detect whether the feed current 2 is cut off or not, and according to the embodiment shown in FIG. , each feeder line 121. 33. , and row-side guide wire wheel 33. A detection circuit 34x is provided in each row.
1. Just by providing the detection circuit 34Y in each column, it becomes possible to detect the rack 3 in which the power supply current I2 is cut off, as described above.

Note that FIGS. 2 to 4 are only one embodiment of the present invention (claims 1 and 2), and for example, the current circuit breaker 1
00 is not limited to the no-fuse breaker (NFB) 21, and many other modifications may be considered, such as a fuse without an alarm contact, but the effects of the present invention do not change in any case. Further, the configuration of the voltage change detection means 400 is not limited to the illustrated detection circuit 34, and for example, the comparison voltage V is applied to the reference voltage VTN generation circuit of the comparator 346. .

Although many other modifications may be considered, such as providing a hysteresis characteristic by feeding back, the effect of the present invention remains the same in any case. Furthermore, it goes without saying that the power supply system to which the present invention is applied is not limited to the power supply system in the exchange shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention (claims 1 and 2), there is no need to use a current breaker with an alarm contact, and there is no need to electrically connect the current breaker and the power supply line to the specified value. It becomes possible to realize a current interruption detection method that can detect interruption of only the power supply current.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention; FIG. 1(a) shows the principle regarding the present invention (Claim 1), FIG. FIG. 2 is a diagram showing a current interruption detection method according to an embodiment of the present invention (claim 1);
FIG. 3 is a diagram showing an example of the detection output waveform in FIG. 2,
Fig. 4 is a diagram showing a current interruption detection method according to an embodiment of the present invention (M requirement 2), Fig. 5 is a diagram showing an example of a power supply system to which the present invention applies, and Fig. 6 is a diagram showing a conventional current FIG. 7 is a diagram showing an example of a fuse with various contacts, FIG. 8 is a diagram showing an example of another conventional current interrupt detection method, and FIG. 9 is a diagram showing an example of another conventional current interrupt detection method. FIG. 10 is a diagram showing an example of the detection output waveform in FIG. 9. In the figure, l is the main power supply unit, 2 is the main distribution board, 3 is the rack,
4 is an overhead row, 5 is a distribution board, 6 is an alarm display device, 7 is a central control device, 10.11.12 and 200 are power supply lines, 20
and 21 is a no-fuse breaker (NFB), 22 is a fuse with alarm contact, and 30 is a current interrupt detection device (DET).
), 31.32 and 34 are detection circuits, 33 and 30
0 is a guide wire ring, 33x is a row side guide wire ring, 33V- is a row side guide wire ring, 100 is a current breaker, 211 is a current cutoff contact, 212 is an electromagnet, 213 and 222 are alarm contacts, 221 is a Fuse, 301 is the first guide ring, 302
is the second guide ring, 311 is the power source, 312.314.3
21322.324.325.328.341.342
．． 344 and 345 are resistors, 313 and 327 are photocouplers, 3]5 and 329 are inverters, 323 is a constant voltage diode, 326 and 346 are comparators, 34
3 is a capacitor, 347 is a flip-flop (FF), 8 is a change-over switch, 00 is a voltage change detection hand flag (Claim 1) (b) Principle diagram of the invention 51 Figure 2 (NFF3) Non-kinmei (Claim 1) Figure 2 [NFB] f Coming current dust, m detection power type Other conventional current interruption #n Figure 3

Claims (2)

[Claims] (1) A guide ring (300) is provided on a power feed line (200) that supplies a power supply current to a load via a current breaker (100), and the current breaker (100) When the feed current is cut off, the guide wire ring (300
) Voltage change detection means (4) for detecting the induced voltage generated in
00) is provided corresponding to each of the guide wire rings (300), and the interruption of the feed current is detected by the detection output of the voltage change detection means (400). (2) A plurality of current breakers (100) are arranged in a matrix, and each feeder line (200) that supplies the feeder current to the load via each of the current breakers (100) has a first guiding wire. A ring (301) and a second guide ring (302) are provided, voltage change detection means (400) are provided corresponding to each row and each column, and each current breaker (100) is arranged in the same row. Each first guide wire ring (301) corresponding to is connected in series,
Voltage change detection means (40
0) and arranged in the same row.
100) are connected in series, respectively, and connected to a voltage change detection means (400) provided corresponding to each column, to detect a voltage change corresponding to each row. The detection means (400) detects a current generated in the corresponding first guide wire (301) when an arbitrary current breaker (100) corresponding to each row interrupts a power supply current of a predetermined value or more. Voltage change detection means (400) that detects the induced voltage via another first induction wire ring (301) connected in series, and corresponds to each of the rows.
is the induced voltage generated in the corresponding second induction wire ring (302) when an arbitrary current breaker (100) corresponding to each row interrupts a power supply current of a predetermined value or more, Through the combination of the detection outputs of the voltage change detection means (400) provided corresponding to each row and each column, detected via another second guide wire (302) connected in series, A current interruption detection method characterized by detecting interrupted power supply current.