KR102229637B1 - Method and apparatus for detecting arc in power system - Google Patents

Abstract

An arc detection method and apparatus are provided, wherein the arc detection method includes detecting at least one phase AC voltage pattern among polyphase AC voltage patterns, detecting an optical signal through an arc sensor, and a period of the at least one AC voltage pattern. And comparing the period of the detected optical signal with and determining whether the optical signal is a signal due to an arc based on the comparison.

Description

TECHNICAL FIELD The method and apparatus for detecting arc in power system TECHNICAL FIELD

The present disclosure relates to a method and apparatus for determining whether an arc generated in a power system such as a switchboard or a power transmission panel in an electric power system is detected incorrectly.

The invention according to the present disclosure is a research conducted as part of a technology development project supported by the Korea Institute of Energy Technology Evaluation, funded by the Ministry of Trade, Industry and Energy in 2019 (Task unique number: 20192910100080, Task name: Arc removal system construction through arc signal detection And related safety standards establishment) and research conducted with the support of KEPCO with the government's funding in 2019 (project name: KEPCO's large, small and medium-sized business innovation partnership support project).

Since switchboards and transmission boards are places where human touch can occur frequently, safety from electric accidents is of paramount importance. Safety is important for power system stability as well as because of frequent human touches, as well as distribution boards and transmission boards. However, since there are devices that can generate electric arcs such as power switches in switchboards and transmission boards, it is important for the safety of the power system to continuously monitor the occurrence of arcs. Usually, the switchboard or the transmission board does not explode with a single arc, but if the arc is continuously accumulated, the explosion by the arc occurs in the switchboard or the transmission board.

At the same time, power devices that are likely to generate such arcs are usually installed in dark rooms, and the optical sensor that detects the arc activates the protection circuit that the arc is detected even though the actual arc is not generated by the light penetrating into the dark room, not by the arc for some reason. The case also occurs. Therefore, it has become an important classification task to accurately determine whether the signal detected by the sensor for actual arc detection is an arc that can lead to an actual accident.
Korean Patent Laid-Open Publication No. 13-95947 (Prior Document 1) proposes an invention for blocking the arc detection malfunction according to the load characteristic, and the invention according to the prior document passes a current to detect the false arc detection according to the load characteristic. As a method of using a current sensor for a wire, the current sensor as in Prior Document 1 cannot detect an erroneous arc due to light penetrating into the dark room, not an arc on an electric device mounted in the dark room.

In the power system, even if it is not an actual arc, a technology is required to accurately classify and detect the arc so that the arc is not falsely detected. In addition, when detecting an arc, a technique is also required to determine where the arc occurs.

The arc detection method for solving the above-described problem includes detecting at least one phase AC voltage pattern among polyphase AC voltage patterns, detecting an optical signal through an arc sensor, and a period of the at least one AC voltage pattern. And comparing the period of the detected optical signal, and determining whether the optical signal is a signal due to an arc based on the comparison.

In one embodiment, a period of the at least one AC voltage pattern compared with a period of the detected optical signal is a period of an absolute value of the at least one AC voltage.

As an embodiment, the determining whether the optical signal is a signal due to an arc may include a period of the absolute value pattern of the at least one AC voltage coinciding with a period of the detected optical signal or a period of the detected optical signal. In the case of an integer multiple of, it is characterized in that it is determined that the optical signal is a signal by an arc.

As an embodiment, when it is determined that the optical signal is a signal due to an arc, determining at which point the arc occurs by calculating a time interval between the periodically generated optical signal and the period of the at least one AC voltage pattern. It further includes steps.

In one embodiment, determining at which point the arc occurs is characterized in determining whether an arc occurs at a phase voltage or a line voltage based on the calculated time interval.

In an embodiment, the method further includes displaying and displaying which phase voltage or which line voltage is the point where the arc occurs.

An arc detection apparatus for solving the above-described problem includes a voltage signal detection unit for detecting at least one phase AC voltage pattern among polyphase AC voltage patterns, an arc sensor for detecting an optical signal, and a period of the at least one AC voltage pattern. And a processor that compares the periods of the detected optical signals and determines whether the optical signal is a signal due to an arc based on the comparison.

According to the present disclosure, it is possible to accurately classify and detect an arc so as not to falsely detect an arc even though it is not an actual arc in the power system. It is also possible to determine where the arc occurs when detecting an arc.

1 shows an example of an arc detection system that detects the occurrence of an arc.
2 is a diagram illustrating predicting an arc generation pattern according to a single-phase power supply pattern according to an embodiment of the present disclosure.
3 is a graph showing occurrence of arc detection in a waveform according to an embodiment of the present disclosure.
4 is a flowchart of determining whether an arc is falsely detected according to an embodiment of the present disclosure.
5 is a diagram illustrating application of arc detection according to a phase voltage absolute value pattern of a three-phase AC voltage according to an embodiment of the present disclosure.
6 is a diagram illustrating application of arc detection according to an absolute line voltage pattern of a three-phase AC voltage according to an embodiment of the present disclosure.
7 is a flowchart illustrating an arc detection method according to an embodiment of the present disclosure.
8 is an arc detection apparatus according to an embodiment of the present disclosure.

The terms used in the present specification will be briefly described, and the present disclosure will be described in detail.

The terms used in the present disclosure have selected general terms that are currently widely used as possible while considering functions in the present invention, but this may vary according to the intention or precedent of a technician working in the field, the emergence of new technologies, and the like. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning of the terms will be described in detail in the description of the corresponding disclosure. Therefore, the terms used in the present disclosure should be defined based on the meaning of the term and the overall contents of the present disclosure, not a simple name of the term.

When a part of the specification is said to "include" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary. In addition, terms such as "... unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software. .

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the embodiments. However, the present disclosure may be implemented in various different formats and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description are omitted in order to clearly describe the present disclosure, and similar reference numerals are attached to similar parts throughout the specification.

Power equipment that may cause arcing is usually installed in a dark room, but there are cases in which the optical sensor that detects the arc activates the protection circuit because the arc is detected even though the actual arc is not generated by the light penetrating into the dark room for some reason. Occurs. Therefore, it has become an important classification task to accurately determine whether the signal detected by the sensor for actual arc detection is an arc that can lead to an actual accident.

Therefore, it is important to detect arcs that occur as early as possible to prevent safety accidents such as explosions. Also, it is very important for the efficiency and safety of the power system to accurately detect whether the optical signal detected by the arc detector is caused by an arc.

1 shows an example of an arc detection system that detects the occurrence of an arc.

The arc detection system 100 that detects the occurrence of the arc 101 mainly uses an optical sensor 120 that detects the arc 101 with light. At this time, the weakness in determining the failure is that the optical sensor 120 It is to falsely detect natural light, not arc, as an arc. For example, when an administrator opens the door of the darkroom to check the power switch installed in the darkroom, natural light penetrates into the darkroom, and there is a possibility that the light sensor falsely detects this natural light as an arc. Alternatively, when natural light leaks into the dark room due to poor management of the dark room, the optical sensor may detect simple natural light as an arc, not an arc.

Referring to FIG. 1, when an arc 101 occurs due to a malfunction in a power switch 110 of a power transmission board or a switchboard, the optical sensor 120 detects the arc light and generates a fault signal 111 to generate a protection circuit ( 130). The protection circuit 130 starts a power system protection function according to a fault signal. As an example of the protection function, there is a method of protecting the switch 110 by shorting the ground fault switch 140 connected to the power switch 110.

However, it is important for the arc detection system 100 to determine whether or not the arc is an actual arc when determining that an arc is occurring as described above. If it is not an actual accident but it is treated as an arcing accident and the switchboard switch is grounded, it will cause a disruption in supplying power to the power system due to transmission interruption, and a lot of costs will be wasted in recovering to the previous state from an unexpected power outage accident.

2 is a diagram illustrating predicting an arc generation pattern according to a single-phase power supply pattern according to an embodiment of the present disclosure.

2, 210 denotes a single-phase AC voltage waveform.

The A regions 201, 203, and 205 are regions in which the absolute value of the AC voltage becomes the maximum, and the B regions 202, 204 and 206 are the regions in which the absolute value of the AC voltage becomes the minimum. The arc will hardly occur in the region of point B where the absolute value of the alternating voltage is minimal. Conversely, the arc will eventually have a very high probability of occurring in the area A, where the absolute value of the voltage is high. In conclusion, arcs in the transmission and distribution panel are more likely to occur when the AC voltage is in the A region, and arcs will hardly occur in the B regions where the AC voltage is considerably low. Therefore, it can be assumed that the arc accident will occur in a periodic pattern synchronized with the A regions. If it is not an accidental arc but a simple natural light, it will not be detected as a periodic arc failure signal such as the A region synchronized with the absolute value pattern of the alternating voltage.

Therefore, the arc detection system detects the phase of the input AC voltage and compares it with the arc signal input, but determines whether the arc occurs periodically while occurring in the A region. It can be distinguished whether it is a simple natural light or another light source. The biggest clue that can be distinguished is whether or not there is a periodicity that synchronizes with the A region while the arc to be detected occurs near the absolute value of the AC voltage-for example, A region.

In one embodiment, how large the width of area A, which is a reference area for detecting an input arc as a periodic input, is a designer's choice, but can be set based on arc detection data due to an actual failure. For example, the width of the region A may be set to be 80% or more of the maximum value of the AC voltage, or may be set to be 90% or more of the maximum value of the AC voltage. Alternatively, the period of the AC voltage may be detected and determined as a time width according to the period. That is, if the period of the AC voltage is 16.7ms, the period of the A region will be 8.35ms. At this time, according to the user's setting, the width of area A may be set as 1ms. Of course, the width of area A may vary according to the user's experience or experimental data.

In an embodiment, if it is determined that the arc detection is periodically increasing, the user may adaptively change the area A through the processor of the arc detection apparatus. For example, when there is no arc and there is no failure, the width of area A can be made slightly narrower or wider.

In an embodiment, when the entire power system system is operating normally without failure, when the cycle of the AC voltage is 16.7 ms, the width of the area A may be set to 1.5 ms. However, if the arc detection signal is detected and periodically occurs, in order to detect whether arcing occurs in other areas, the width of area A is expanded to 3ms and then narrowed to 1ms to determine the temporal location of the arc occurrence. And it is possible to determine whether the arc is a false positive or an actual arc.

Likewise, in one embodiment, the width of area B may be set by a designer to a predetermined value in advance. By detecting the zero crossing of the AC voltage, it can be set to a point that becomes 20% or less to 0 of the maximum AC voltage value before and after the point at which the zero crossing occurs, or it can be set to a point that becomes 10% or less to 0 of the AC voltage maximum value. In addition, the width of area B can be set as a time value compared to the period.

However, when it is determined that the arc detection signal is detected and is periodically occurring, the width of the area B is also variably adjusted, and if it is detected that the arc is also occurring in the area B, there is a possibility that the detected signal is not an arc. If it is determined that there is a possibility other than an arc, the determination can be further confirmed by examining whether an arc is detected while narrowing the width of area B.

3 is a graph showing occurrence of arc detection in a waveform according to an embodiment of the present disclosure.

According to FIG. 3, graph 310 is a graph showing an AC voltage.

As shown in FIG. 2, the graph 320 is a graph in which a region in which the maximum value of the AC voltage occurs is displayed in accordance with the AC voltage cycle.

Graph 330 is a graph showing the waveform of the area where the arc occurs (area A) at the maximum value of 310 AC voltage. As can be seen from 330, the arcing point coincides with the period at which the absolute value of the AC voltage according to the 320 graph becomes maximum. The arc detection system according to the present disclosure determines whether an arc generation signal is periodically received by integrating when a signal generated by an arc is received in graph 330 to determine whether it is a false detection due to natural light.

4 is a flowchart of performing an arc false detection according to an embodiment of the present disclosure.

The arc false detection method according to FIG. 4 will be described with reference to the arc detection apparatus according to FIG. 8.

The arc detection apparatus 800 first detects an AC voltage pattern through a voltage sensor called a voltage signal detection unit 820 (S410).

The arc detection device 800 also detects an optical signal through the arc sensor 830 (S420). It may be desirable that the detection of the alternating voltage pattern and the detection of the optical signal are not ordered and are performed simultaneously.

The processor 810 of the arc detection device 800 checks the periodicity of the detected optical signal by comparing it with the AC voltage pattern (S430). The processor 810 may determine whether or not the optical signal being detected is an arc signal based on the periodicity of the detected optical signal (S440). That is, if the detected optical signal has a periodicity that is synchronized with the absolute value pattern of the AC voltage pattern, the detected arc signal is likely to be an actual arc caused by a failure due to a ground fault in an actual power system.

5 is a diagram illustrating an application of arc detection according to a phase voltage absolute value pattern of a three-phase AC voltage according to an embodiment of the present disclosure.

The AC voltage graph of FIG. 5 shows the AC voltage consisting of three phases R, S, and T as absolute values. Referring to FIG. 5, since the R-phase AC voltage is R 510 and the S-phase AC voltage has a phase difference of 120 degrees compared to the R-phase, S 520 will be the S-phase AC voltage. Likewise, since the T-phase AC voltage is delayed by 120 degrees from the S-phase, T 530 will be the T-phase AC voltage.

As in Fig. 2, the probability of occurrence of an arc in a three-phase voltage is in the vicinity of the absolute value of the phase voltage reaching the highest point in each of R(510), S(520), and T(530), and R1(511) and S1(521), respectively. , T1 (531) regions, and although not individually illustrated in FIG. 5, the regions with high probability of arc occurrence have the highest absolute value of the phase voltage of each R (510), S (520), and T (530) periodically. Therefore, R1 (511), S1 (521), T1 (531) will also appear at a period of 180 degrees. The widths of R1 (511), S1 (521), and T1 (531) can be set in advance by the system designer as in FIG. 2, but in order to obtain a uniform arc false detection result, R1 (511), S1 (521), T1 (531) It would be desirable to make each width equal.

Since each of the three-phase AC voltages is connected to each switch at the transmission and distribution end, it is necessary to determine which of the three switches has a failure. In this case, arc sensors that detect arcs can be installed to monitor all voltage switches to which each R, S, T phase voltage is connected. However, it is not necessary to detect all three-phase AC voltages to detect which phase an arc occurs. This is because the three-phase voltages have 120 degrees of phase difference from each other, and the resulting arc pattern will eventually occur with 120 degrees of difference.

As an example, it is assumed that only R1 511 whose absolute value of the phase voltage pattern R 510 is the highest is compared with the arc signal and the period. If the arc signal is continuously detected at a point 60 degrees away from the point where the cycle in which R1 (511) occurs is repeated, this means that an arc is occurring at the maximum point on T (530). Check the voltage switch part or take protective control measures on the T 530. The arc detection device may specifically indicate that an arc is occurring on "T" through a display.

This arc signal continues to accumulate as an integral value each time the period is complete. In other words, an arc failure occurs in any of the R(510), S(520), and T(530) phases by determining whether the integral value at which the arc signal is generated is large at which point periodically coincides with the R1, S1, and T1 areas. It detects whether it is, and finally decides

In one embodiment, if the arc signal is continuously detected at a point 120 degrees away from the point where the cycle of R1 511 is repeated in the same situation as in the previous example-when only R1 511 is synchronized with the arc signal, it is S It can be seen that an arc is occurring at the maximum point on (520).

In one embodiment, the period of generating the arc signal may be shorter than the period of the R1 511 when compared with the period of generating the arc signal by periodically monitoring the R1 511. That is, when the period of R (510) is 16.7 ms, the period of R1 (511) will be 8.35 ms. However, as in the above two embodiments, if an arc is generated in both the S (520) phase and the T (530) phase, the arc generation period will appear shorter than the period of R1 (511). If an arc is generated in both S (520) and T (530) phases, the period of R1 (511) will be an integer multiple of the period in which the arc occurs.

The foregoing example is only an example, and it is possible to determine exactly at which point (which phase voltage) arc generation occurs while monitoring all of the three-phase voltage maximum points 511, 521, and 531.

6 is a diagram illustrating an application of arc detection according to an absolute line voltage pattern of a three-phase AC voltage according to an embodiment of the present disclosure.

Previously, in FIG. 5, where an arc occurs at a phase voltage of a three-phase alternating current voltage, it has been discussed. In FIG. 6, it is possible to find out at which point an arc occurs according to an absolute value pattern of a phase-to-phase voltage or a line-to-line voltage.

According to FIG. 6, the three-phase AC voltage is shown as an R-phase voltage 510, an S-phase voltage 520, and a T-phase voltage 530. In addition, in FIG. 6, each of the three-phase AC voltages is represented by an absolute value.

The absolute value of the three-phase line voltage is shown as the RS line voltage 6010, the RT line voltage 6020, and the ST line voltage 6030.

As shown in FIG. 5, when the highest absolute value R1 511 of the R-phase voltage 510 is set as a reference, the highest absolute value of the RS line voltage 6010 among the line voltages becomes 6011. The highest absolute value of the RT line voltage 6020 is 6021, and similarly, the highest absolute value of the ST line voltage 5030 is 6031.

In one embodiment, the highest point of R1 511 will be repeated in a period of 180 degrees. If the arc signal is detected after a delay of 30 degrees based on the highest point of the absolute value corresponding to 511, according to FIG. 6, the corresponding point is the RT line voltage 6020. It can be seen that the absolute value of) is the highest point 6021. Thus, the arc detection system can detect that a problem has occurred on the RT line voltage side.

In one embodiment, the highest point of R1 511 will be repeated in a period of 180 degrees. If an arc signal is detected after a delay of 90 degrees with respect to the highest point of the absolute value corresponding to 511, according to FIG. 6, the corresponding point is the ST line voltage 6030. It can be seen that the absolute value of is the highest point (6031). Therefore, it can be seen that the arc detection system has a problem in the ST line voltage side. In this way, when an arc occurs due to a line-to-line short circuit or line-to-line ground fault, it is possible to accurately determine at which line voltage the problem occurs.

In one embodiment, if an arc is detected at both the RT line voltage 6020 and the ST line voltage 6030, the period of the arc detection signal will be shorter than the period of the peak of R1 511. In this case, it is possible to determine not only the exact arc occurrence point, but also that the arc is occurring at a plurality of points. Normally, when the arc occurs at such a plurality of points, the period of the peak of R1 (511) will be an integer multiple of the period of the arc detection signal. .

The above example is only an example, and it is possible to determine exactly where the arc occurs (which line voltage) while monitoring all of the absolute value peaks (ie, 6011, 6021, 6031) of the three-phase line voltage.

7 is a flowchart illustrating an arc detection method according to an embodiment of the present disclosure.

The flowchart according to FIG. 7 will be described with reference to each component of the arc detection apparatus 800 of FIG. 8.

The arc detection apparatus 800 detects at least one phase AC voltage pattern among the polyphase AC voltage patterns through a voltage sensor called the voltage signal detection unit 820 (S710).

The arc detection device 800 detects an optical signal through the arc sensor 830 (S720).

The processor 810 of the arc detection apparatus 800 compares the period of the at least one AC voltage pattern with the period of the detected optical signal (S730). In this case, the AC voltage pattern may be used as a cycle of an absolute value of the AC voltage according to an embodiment. If the period of the optical signal and the period of the AC voltage pattern coincide or the period is shorter than that of the AC voltage pattern, but the optical signal shows periodicity, it is determined as an arc signal.

The processor 810 determines whether the optical signal is a signal due to an arc based on the above comparison (S740). If the optical signal exhibits periodicity, it may be determined that the arc signal is generally detected. This is because natural light does not exhibit periodicity. If natural light without periodicity or light from a general lamp is detected, it is judged that it is not an arc-it is a false detection.

Further, if the processor 810 determines that the optical signal is an arc signal based on the above comparison, the processor 810 may determine at which point the arc occurs based on the interval between the AC voltage pattern period and the period of the optical signal. That is, it is possible to determine whether an arc occurs at which phase voltage or which of the phase voltages or line voltages, and which line voltages among line voltages, according to the time interval between periods.

The display 840 of the arc detection device 800 may display a point where an arc occurs (S750).

8 is an arc detection apparatus according to an embodiment of the present disclosure.

The arc detection apparatus 800 according to an embodiment includes a processor 810, a voltage signal detection unit 820, an arc sensor 830, and a display 840.

The voltage signal detector 820 detects a voltage. Since the voltage is generally an alternating voltage, it will be possible to detect an alternating voltage waveform. The voltage signal detector 820 will be a voltage sensor that senses an AC voltage.

The arc sensor 830 senses an arc generated in the power system. In general, since the arc is in the form of light, the arc sensor 830 uses an optical sensor.

The processor 810 receives a voltage waveform (voltage pattern) according to the voltage signal detection unit 820 and a signal from the arc sensor 830 as inputs and checks each periodicity to determine whether an arc is falsely detected and a point where the arc has occurred. Judge.

If an arc is detected, the processor 810 may show the point where the arc occurs on the display 840, on which phase or at which line voltage, the arc is generated. Further, in this case, the processor 810 notifies the protection control unit 850 that an arc has occurred so that the protection circuit of the power system can start a protection function of outputting a protection control signal. The arc detection device 800 may also include an upper protection control unit 850 in the device, if necessary.

The methods according to embodiments may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -A hardware device specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like.

Although the embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also included in the scope of the present invention. Belongs to.

100; Arc detection system
101; Arc
110; Power switch
111; Fault signal
120; Light sensor
130; Protection circuit
140; Ground fault switch
800; Arc detection device
810; Processor
820; Voltage signal detection unit
830; Arc sensor
840; display
850; Protection control unit

Claims (12)

Detecting at least one phase alternating voltage pattern among the multiphase alternating voltage patterns of electric devices installed in the darkroom;
Detecting an optical signal due to inflow of external light around the electric device through an arc sensor;
Comparing a period of the at least one AC voltage pattern with a period of the detected optical signal; And
And determining whether the optical signal is a signal due to an arc based on the comparison. The method of claim 1, wherein a period of the at least one AC voltage pattern compared with a period of the detected optical signal is a period of an absolute value of the at least one AC voltage. The method of claim 2, wherein determining whether the optical signal is a signal due to an arc comprises: a period of the absolute value pattern of the at least one AC voltage coincides with a period of the detected optical signal or of the detected optical signal. In the case of an integer multiple of a period, it is determined that the optical signal is a signal due to an arc. The method of claim 2,
When it is determined that the optical signal is a signal due to an arc, determining at which point the arc occurs by calculating a time interval between the periodic light signal and the period of the at least one AC voltage pattern. Arc detection method. The method of claim 4, wherein determining at which point the arc occurs
Based on the calculated time interval, the arc detection method, characterized in that it is determined whether the point where the arc occurs is a phase voltage or a line voltage. The method of claim 5, further comprising displaying and displaying which phase voltage or which line voltage is the point where the arc occurs. A voltage signal detector configured to detect at least one phase AC voltage pattern among polyphase AC voltage patterns of electric devices installed in the darkroom;
An arc sensor that detects an optical signal generated by inflow of external light around the electric device; And
And a processor configured to compare a period of the at least one AC voltage pattern with a period of the detected optical signal, and to determine whether the optical signal is a signal due to an arc based on the comparison, and installed in the dark room. Arc detection device. The arc detection apparatus according to claim 7, wherein the period of the at least one alternating voltage pattern compared with the period of the detected optical signal is a period of an absolute value of the at least one alternating voltage. The method of claim 8, wherein the processor determines whether the optical signal is a signal due to an arc, by the processor, the period of the absolute value pattern of the at least one AC voltage coincides with the period of the detected optical signal or the An arc detection apparatus, characterized in that, when it is an integer multiple of a period of the detected optical signal, it is determined that the optical signal is a signal due to an arc. The method of claim 8,
When the processor determines that the optical signal is a signal due to an arc, the processor calculates a time interval between the periodic optical signal and the period of the at least one AC voltage pattern to determine at which point the arc occurs. Arc detection device, characterized in that. The method of claim 10, wherein the processor determines at which point the arc occurs,
The arc detection apparatus, characterized in that the processor determines whether the point where the arc occurs is a phase voltage or a line voltage based on the calculated time interval. The arc detection apparatus according to claim 11, further comprising a display that displays which phase voltage or which line voltage is the point where the arc occurs.

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