Arc detection system, arc detection method, and program recording medium

Abstract

An arc detection system (100) includes a first obtaining section (11), a second obtaining section (12), and a determination section (13). The first obtaining section (11) obtains a measurement result of a current (I1) or a voltage (V1), the current (I1) being a current flowing in a power feeding line (L1) to which a power source (2) supplies electric power, the voltage (V1) being a voltage in the power feeding line (L1). The second obtaining section (12) obtains quality information relating to quality of communication with a device (3) connected to the power feeding line (L1) by power line communication via the power feeding line (L1) and the device (3). The determination section (13) determines whether or not an arc fault has occurred in the power feeding line (L1) based on a component of a specific frequency band in the measurement result obtained by the first obtaining section (11) and the quality information obtained by the second obtaining section (12).

Description

Technical Field

[0001] This invention relates to an arc detection system, an arc detection method, and a program recording medium for determining the possibility of an arc fault occurring in a feeder line. Background Technology

[0002] Patent Document 1 discloses an arc detection unit for detecting electric arcs. This arc detection unit includes: a voltage detection unit that measures the voltage between an input wire fed into a terminal block and an output wire discharged from the terminal block; and a current detection unit that measures the current in the output wire discharged from the terminal block. Furthermore, this arc detection unit identifies electrical noise and electric arcs within the terminal block by simultaneously detecting changes in both the voltage value of the voltage detection unit and the current value of the current detection unit.

[0003] (Existing technical literature)

[0004] (Patent Documents)

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-7765 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] This invention provides an arc detection system, an arc detection method, and a program recording medium that can easily prevent false detection of arc faults.

[0008] The means used to solve the problem

[0009] One embodiment of the present invention relates to an arc detection system comprising a first acquisition unit, a second acquisition unit, and a determination unit. The first acquisition unit acquires measurement results of current or voltage, wherein the current is a current flowing in a feeder line powered by a power source, and the voltage is the voltage in the feeder line. The second acquisition unit acquires quality information related to the quality of communication between the feeder line and a device connected to the feeder line through power line communication. The determination unit determines whether an arc fault has occurred in the feeder line based on a specific frequency band component in the measurement results acquired by the first acquisition unit and the quality information acquired by the second acquisition unit.

[0010] One embodiment of the present invention relates to an arc detection method comprising a first obtaining step, a second obtaining step, and a determining step. In the first obtaining step, a measurement result of current or voltage is obtained, wherein the current is the current flowing in a feeder line powered by a power source, and the voltage is the voltage in the feeder line. In the second obtaining step, quality information related to the quality of communication between the feeder line and a device connected to the feeder line is obtained through power line communication. In the determining step, a determination is made as to whether an arc fault has occurred in the feeder line based on a specific frequency band component in the measurement result obtained in the first obtaining step and the quality information obtained in the second obtaining step.

[0011] One embodiment of the present invention relates to a program recording medium that records a program that causes one or more processors to execute the arc detection method.

[0012] Invention Effects

[0013] One embodiment of the present invention has the advantage of easily preventing false detection of arc faults. Attached Figure Description

[0014] Figure 1 This is a schematic diagram showing the overall configuration of the arc detection system according to the embodiments.

[0015] Figure 2A This is a timing diagram showing a first judgment example performed by the judgment unit of the arc detection system according to the embodiment.

[0016] Figure 2B This is a timing diagram showing a second judgment example in which the judgment unit of the arc detection system according to the embodiment makes a judgment.

[0017] Figure 2C This is a timing diagram showing a third judgment example in which the judgment unit of the arc detection system according to the embodiment makes a judgment.

[0018] Figure 3 This is a flowchart illustrating an example of the operation of the arc detection system according to the embodiment. Detailed Implementation

[0019] The embodiments of the present invention will now be described with reference to the accompanying drawings. The embodiments described below are all specific examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, the arrangement and position of constituent elements, connection methods, steps, and the order of steps shown in the following embodiments are all examples and are not intended to limit the present invention.

[0020] Furthermore, the diagrams are schematic diagrams, not rigorous illustrations. Also, in each diagram, substantially identical components are given the same symbols, and repetitive explanations are omitted or simplified.

[0021] [constitute]

[0022] use Figure 1 The arc detection system involved in the implementation method will be described. Figure 1 This is a schematic diagram showing the overall configuration of the arc detection system 100 according to the embodiments.

[0023] The arc detection system 100 is primarily used to determine whether an arc fault has occurred in the feeder line L1, which is powered by the power source 2. That is, the feeder line L1 may be damaged or broken due to external factors or years of aging, which could lead to an arc (arc discharge), resulting in a potential arc fault. Therefore, the arc detection system 100 is mainly used to detect potential arc faults in the feeder line L1.

[0024] Specifically, the arc detection system 100 is used in a so-called DC (Direct Current) distribution network 200. The DC distribution network 200 is configured to include one or more feeder lines L1. Figure 1 In the diagram, only one feeder line L1 is shown. The DC distribution network 200 is supplied with DC power by the power source (in this case, the DC power source) 2. Each feeder line L1 consists of a feeder line connected to the positive terminal of the output side of the power source 2 and a feeder line connected to the negative terminal of the output side of the power source 2.

[0025] Here, when the DC distribution network 200 has only one feeder line L1, the feeder line L1 is supplied with DC power by the power source 2. Furthermore, when the DC distribution network 200 has multiple feeder lines L1, one end of each of the multiple feeder lines L1 is connected to more than one branch point. Therefore, if DC power is supplied to any one feeder line L1 by the power source 2, the DC power will also be supplied to the other feeder lines L1 via more than one branch point.

[0026] In this embodiment, the power source 2 is a power converter equipped with an AC / DC converter 21. The power source 2 converts the alternating current (AC) output from the power system 300 into direct current (DC), and outputs the converted DC to the feeder line L1 connected to the power source 2. If the DC distribution network 200 has multiple feeder lines L1, the DC output to that feeder line L1 is also output to other feeder lines L1. Furthermore, in this embodiment, the power source 2 can be any configuration that outputs DC, and may be a distributed power source such as a solar cell, a power source such as a battery, or a combination of these power sources and a power converter (e.g., a power converter equipped with a DC / DC converter circuit).

[0027] Each feeder line L1 is, for example, constructed from a conduit rail, and can accommodate one or more devices 3. That is, one or more devices 3 can be freely positioned at any location on each feeder line L1. Of course, the placement of each feeder line L1, capable of accommodating one or more devices 3, can be predetermined. In this embodiment, although each feeder line L1 is positioned on the ceiling of the facility, it can also be mounted on the floor, walls, or furniture of the facility.

[0028] Device 3 has a load 31 and a pair of connection terminals. Furthermore, device 3 has the function of communicating with the second acquisition unit 12 (described later) of the arc detection system 100. The communication function operates when device 3 is in operation. That is, in this embodiment, when device 3 is connected to the feed line L1, device 3 can communicate with the second acquisition unit 12; however, when device 3 is not connected to the feed line L1, device 3 cannot communicate with the second acquisition unit 12.

[0029] Device 3 can be attached to and detached from feeder line L1 via a pair of connecting terminals. Specifically, when installing device 3 onto feeder line L1, with the pair of connecting terminals of device 3 already inserted into the guide rail (feeder line L1), device 3 is rotated clockwise or counterclockwise by a predetermined angle (e.g., 90 degrees) from the insertion direction. Accordingly, the pair of connecting terminals are fixed in contact with a pair of connecting conductors provided on feeder line L1, thus connecting device 3 to feeder line L1 electrically and mechanically.

[0030] To remove device 3 from feeder line L1, rotate device 3 by a predetermined angle in the opposite direction to the direction described above, viewed from the insertion direction of device 3. This releases the contact between the pair of connecting terminals and the pair of connecting conductors, allowing device 3 to be removed from feeder line L1. With device 3 installed on feeder line L1, load 31 receives and is driven by DC power supplied by power source 2 via feeder line L1.

[0031] In this embodiment, although device 3 is a lighting fixture, it could also be a speaker, camera, sensor, or USB PD (Power Delivery). In other words, device 3 can be any device other than a lighting fixture, as long as the load 31 can receive and drive it. Furthermore, although in this embodiment, the devices 3 connected to each feeder line L1 are all lighting fixtures, and there is only one type, the types of devices 3 connected to each feeder line L1 can be multiple. For example, the devices connected to each feeder line L1 could be lighting fixtures, speakers, cameras, sensors, or USB PD. These devices 3 can be all connected to one feeder line L1, or they can be connected separately to multiple feeder lines L1.

[0032] The arc detection system 100 includes a first acquisition unit 11, a second acquisition unit 12, a judgment unit 13, a notification unit 14, and a stop unit 15 as functional components for determining whether an arc fault has occurred. In this embodiment, the first acquisition unit 11, the judgment unit 13, the notification unit 14, and the stop unit 15 are provided in the power supply 2. Furthermore, the second acquisition unit 12 is separately provided from the power supply 2 in a communication module 20 connected to the feed line L1. The communication module 20 is configured, for example, to communicate with the power supply 2 via wireless communication or power line communication (PLC).

[0033] The arc detection system 100 in both the power supply 2 and the communication module 20 is, for example, a microcomputer or a device equipped with a microcomputer. The microcomputer is a semiconductor integrated circuit containing ROM (Read Only Memory) and RAM (Random Access Memory) for storing programs, a processor (CPU) for executing programs, a timer, an A / D converter, and a D / A converter, etc. Any one of the first acquisition unit 11, the second acquisition unit 12, the judgment unit 13, the notification unit 14, and the stop unit 15 can be implemented by the processor executing the aforementioned program.

[0034] The first acquisition unit 11 acquires the measurement results of the current I1 flowing in the feeder line L1, which is powered by the power source 2, or the voltage V1 in the feeder line L1. In this embodiment, the first acquisition unit 11 acquires the measurement results of the measured current I1 by sampling the current at a predetermined period (sampling period) using an ammeter 22. That is, the first acquisition unit 11 acquires the measurement results of the current I1 at a predetermined period from the ammeter 22. The ammeter 22 is installed between the power source 2 and the feeder line L1 to measure the current flowing in the feeder line on the negative side of the feeder line L1 (that is, the current I1 flowing in the feeder line L1). Alternatively, the ammeter 22 may be built into the power source 2.

[0035] The second acquisition unit 12 obtains quality information related to the quality of communication between itself and the device 3 via power line communication through the feeder line L1 and the device 3 connected to the feeder line L1. There is no particular limitation on the communication standard for the power line communication between the second acquisition unit 12 and the device 3. In this embodiment, the quality information includes the degree of quality of the power line communication between the second acquisition unit 12 and the device 3, and the degree of communication quality is represented by the frequency of communication anomalies. That is, the second acquisition unit 12 obtains the frequency of communication anomalies as quality information. Communication anomalies may include, for example, situations where a signal unilaterally transmitted from the device 3 cannot be received, or even if the signal can be received, only a portion of the data can be received. Furthermore, communication anomalies may also include situations where, when the second acquisition unit 12 sends a request signal including a request for a reply to the device 3, a response signal from the destination device 3 of the request signal cannot be received, or even if a response signal can be received, only a portion of the data can be received.

[0036] Furthermore, the frequency of communication anomalies is represented by the number of communication anomalies occurring per unit time (e.g., 1 minute, several minutes, 1 hour, or several hours) or the number of retries sent from the second acquisition unit 12 to the device 3 per unit time. In other words, the lower the frequency of communication anomalies, the higher the quality of communication; conversely, the higher the frequency of communication anomalies, the lower the quality of communication.

[0037] In this embodiment, the second acquisition unit 12 and the operating device 3 connected to the feed line L1 communicate at regular intervals (e.g., hundreds of milliseconds). For example, the second acquisition unit 12 may also communicate with the device 3 by receiving signals unilaterally transmitted from the operating device 3 connected to the feed line L1. Furthermore, the second acquisition unit 12 may also communicate with the device 3, for example, by broadcasting a request signal and receiving a response signal from the device 3 that received the request signal.

[0038] Furthermore, the signal sent from device 3 to the second acquisition unit 12 includes identification information identifying device 3 as the sender. Thus, the arc detection system 100 can grasp quality information for each device 3.

[0039] The determination unit 13 determines whether an arc fault has occurred in the feeder line L1 based on the components of a specific frequency band in the measurement results obtained by the first acquisition unit 11 and the quality information obtained by the second acquisition unit 12. Specifically, the determination unit 13 performs frequency analysis on the measurement results of the current I1 obtained by the first acquisition unit 11. Frequency analysis refers to, for example, calculating the spectrum of the measurement results of the current I1 by performing a Fourier transform (in this case, FFT) on the time waveform of the measurement results of the current I1. Then, the determination unit 13 refers to the calculated spectrum and determines that an arc has occurred if the measurement results of the current I1 include components of a specific frequency band above a first predetermined value. The specific frequency band is, for example, a frequency band that includes the frequency of noise generated in the event of an arc fault. As an example, the specific frequency band is tens of kHz, which is a high-frequency band. In addition, the frequency of the noise generated in the above case can be determined experimentally.

[0040] Furthermore, the determination unit 13 not only determines whether an arc has occurred based on the measurement results obtained by the first acquisition unit 11, but also determines whether an arc fault has occurred in the feeder line L1 by referring to the quality information obtained by the second acquisition unit 12. In other words, the determination unit 13 will not determine that an arc fault has occurred in the feeder line L1 if it determines that an arc has occurred solely based on the measurement results obtained by the first acquisition unit 11. The process of determining the occurrence of an arc fault in this way will be explained below.

[0041] The two possible types of electric arcs in the DC distribution network 200 are: arcs caused by a broken or nearly broken feeder line L1, and arcs generated momentarily when installing or removing device 3 from feeder line L1. Specifically, if the installation of device 3 onto feeder line L1 is not smooth, the load 31 of device 3 may repeatedly switch between being connected to and disconnected from feeder line L1 for a short period, potentially causing contact bounce. Furthermore, during contact bounce, an arc may occur when the load 31 is momentarily disconnected from feeder line L1 while current is flowing. Similarly, contact bounce may also occur when removing device 3 from feeder line L1. Again, during contact bounce, an arc may occur when the load 31 is momentarily disconnected from feeder line L1 while current is flowing. Such arcing caused by contact bounce can occur not only in DC distribution networks 200, but also in AC (Alternating Current) distribution networks. Especially when device 3 is installed on feeder line L1 with a less than ideal distance between the electrodes of device 3 and feeder line L1, the arc will be difficult to extinguish.

[0042] Furthermore, in the DC distribution network 200, if an arc occurs due to a broken or nearly broken feeder line L1, a specific frequency band component overlaps with the current I1 (or voltage V1). Therefore, the determination unit 13 can determine that an arc has occurred by monitoring the specific frequency band component of the current I1 (or voltage V1). However, if the load 31 of the device 3 experiences a sudden change, it is also possible that a specific frequency band component overlaps with the current I1 (or voltage V1). This phenomenon can occur not only in the DC distribution network 200 but also in the AC distribution network.

[0043] Here, although an arc caused by a broken or nearly broken feeder line L1 is more likely to be the cause of an arc fault, the aforementioned phenomena do not actually lead to an arc in feeder line L1, and therefore will not be the cause of an arc fault. Furthermore, an arc caused by contact chatter is generally extinguished within a short period, so it is unlikely to be the cause of an arc fault. Therefore, in the arc detection system 100, it is desirable not to detect the aforementioned phenomena or the short-term arc caused by contact chatter, but to primarily determine the occurrence of an arc caused by a broken or nearly broken feeder line L1 as the occurrence of an arc fault.

[0044] Therefore, in this embodiment, to meet the above requirements, the determination unit 13 determines whether an arc fault has occurred in the feeder line L1 as follows: First, the determination unit 13 determines whether an arc has occurred based on the measurement results obtained by the first acquisition unit 11. Then, if an arc is determined to have occurred, the determination unit 13 monitors the duration of the determination. If the duration is less than a first threshold, the determination unit 13 determines that no arc fault has occurred in the feeder line L1, regardless of the quality information obtained by the second acquisition unit 12. Furthermore, if the duration is above the first threshold and less than the second threshold, the determination unit 13 determines whether an arc fault has occurred in the feeder line L1 as in the first or second determination example shown below. And, if the duration is above the second threshold, the determination unit 13 determines whether an arc fault has occurred in the feeder line L1 as in the third determination example shown below. The first and second thresholds can also be preset by the user of the arc detection system 100.

[0045] Figure 2A This is a timing diagram showing a first judgment example performed by the judgment unit 13 of the arc detection system 100 according to the embodiment. Figure 2B This is a timing diagram showing a second judgment example performed by the judgment unit 13 of the arc detection system 100 according to the embodiment. Figure 2C This is a timing diagram showing a third judgment example performed by the judgment unit 13 of the arc detection system 100 according to the embodiment. Figures 2A to 2C In the timing diagrams of the upper half of each diagram, the pulses represent the duration of the judgment made by the judgment unit 13 that an arc has occurred. Furthermore, in Figures 2A to 2C In the timing diagrams of the lower half of each diagram, the pulses indicate an anomaly in the power line communication between the second acquisition unit 12 and the device 3. Additionally, in Figure 2A as well as Figure 2C Since no abnormalities occurred in the power line communication between the second acquisition unit 12 and the device 3 as will be described later, the pulses are not illustrated.

[0046] like Figure 2A As shown, in the first judgment example, at time t1, the judgment unit 13 determines that an arc has occurred based on the measurement results obtained by the first acquisition unit 11. At this time (hereinafter also referred to as the "judgment time") t1, the second acquisition unit 12 obtains little or no quality information indicating an abnormality in the power line communication with the device 3. Therefore, in the first judgment example, since the communication quality is high at judgment time t1, the judgment unit 13 determines that no arc has occurred in the feeder line L1, and no arc fault has occurred in the feeder line L1.

[0047] like Figure 2B As shown, in the second judgment example, at judgment time t1, the second acquisition unit 12 frequently acquires quality information indicating abnormal power line communication with device 3. Therefore, in the second judgment example, since the communication quality is low at judgment time t1, the judgment unit 13 judges that an arc fault has occurred due to a broken or nearly broken feeder line L1.

[0048] Thus, in both the first and second judgment examples, if the judgment unit 13 determines that an arc has occurred based on the measurement results obtained by the first acquisition unit 11, and the communication quality obtained by the second acquisition unit 12 is low during the judgment period, then the judgment unit 13 determines that an arc fault has occurred. Here, whether the communication quality is low is determined by whether the frequency of communication anomalies is above a threshold. Specifically, if the frequency of communication anomalies is less than the threshold, the judgment unit 13 determines that the communication quality is high; if the frequency of communication anomalies is above the threshold, the judgment unit 13 determines that the communication quality is low. The threshold is, for example, preset by the user of the arc detection system 100.

[0049] In addition, the "judgment time" includes not only the instant of judgment time t1, but also the range from the time before the specified time of judgment time t1 to the time after the specified time.

[0050] like Figure 2C As shown, in the third judgment example, although the second acquisition unit 12 did not obtain quality information indicating an abnormality in power line communication with device 3, the duration of the judgment made by the judgment unit 13 as indicating that an arc had occurred was longer than the second threshold (threshold time Th1). Therefore, in the third judgment example, the judgment unit 13 judges that an arc fault has occurred because the feeder line L1 was broken or nearly broken, without referring to the quality information obtained by the second acquisition unit 12. Thus, if the judgment unit 13 judges that an arc fault has occurred for a period exceeding the second threshold (threshold time Th1) based on the measurement results obtained by the first acquisition unit 11, it judges that an arc fault has occurred regardless of the quality information obtained by the second acquisition unit 12.

[0051] The notification unit 14 may notify the surrounding area of ​​an arc fault by, for example, illuminating a light or emitting a buzzer. Furthermore, the notification unit 14 may also notify the owner or manager of the arc detection system 100 of an arc fault by sending information indicating that an arc fault has occurred to an information terminal. As an example, the information terminal may include portable terminals such as smartphones or tablets, as well as personal computers.

[0052] If the determination unit 13 determines that an arc fault has occurred, the stopping unit 15 stops the current flowing in the feeder line L1. Accordingly, if an arc discharge occurs due to an arc fault, the arc discharge disappears.

[0053] The stopping unit 15 stops the current flowing in the feeder line L1, for example, by controlling a switch connected to the feeder line L1. The switch can be, for example, a mechanical switch or a semiconductor switch. A mechanical switch can be, for example, a relay or a circuit breaker, while a semiconductor switch can be, for example, a transistor or a diode.

[0054] Furthermore, the switch connected to the feeder line L1 can be either directly connected to the feeder line L1 or indirectly connected to it. For example, this switch is used to implement the AC / DC conversion function in the AC / DC converter 21. Even if this switch is not directly connected to the feeder line L1, it is still indirectly connected to the feeder line L1, so it can be considered a switch connected to the feeder line L1. The stop unit 15 stops the operation of opening the switch, for example, by controlling the switch, thereby stopping the current flowing in the feeder line L1.

[0055] Alternatively, the switch can be configured to toggle between turning the power supply 2 on and off. In this case, the stop unit 15 controls the switch to turn off the power supply 2, thereby stopping the current flowing in the feeder line L1.

[0056] Furthermore, the switch can be installed on the feeder line L1, and the switch can be configured to switch between connecting and disconnecting the feeder line L1. For example, the stop unit 15 can control the switch to disconnect the feeder line L1, thereby stopping the current flowing in the feeder line L1.

[0057] [Work]

[0058] The following uses Figure 3 An example of the operation of the arc detection system 100 according to the implementation method will be described. Figure 3 This is a flowchart illustrating an example of the operation of the arc detection system 100 according to the embodiment.

[0059] First, the first acquisition unit 11 acquires the measurement result of current I1 over a predetermined period from ammeter 22 (S1). Processing S1 corresponds to the first acquisition step ST1 of the arc detection method. Next, the second acquisition unit 12 acquires quality information from each device 3 through power line communication (S2). Processing S2 corresponds to the second acquisition step ST2 of the arc detection method. Then, the judgment unit 13 determines whether an arc has occurred based on the specific frequency band components in the measurement result of current I1 acquired by the first acquisition unit 11 (S3). Here, the judgment unit 13 makes the judgment by performing frequency analysis on the measurement result of current I1 acquired by the first acquisition unit 11.

[0060] If the determination unit 13 determines that an electric arc has occurred (S3 "Yes"), it monitors the duration of the determination that an electric arc has occurred (S4). On the other hand, if the determination unit 13 determines that no electric arc has occurred (S3 "No"), it determines that no electric arc fault has occurred (S7).

[0061] If an arc is detected, and the duration is less than the first threshold (S4 "Yes"), the determination unit 13 determines that no arc fault has occurred (S7). Furthermore, if the duration is greater than or equal to the second threshold (S4 "No", S5 "No"), the determination unit 13 determines that an arc fault has occurred (S8). On the other hand, if the duration is greater than or equal to the first threshold (S4 "No") and less than the second threshold (S5 "Yes"), the determination unit 13 refers to the quality information obtained by the second acquisition unit 12 and monitors whether the communication quality of each device 3 at determination time t1 is low (i.e., whether the frequency of communication abnormalities is greater than or equal to the threshold) (S6).

[0062] If the frequency of communication anomalies in any of the devices 3 at judgment time t1 is less than the threshold (S6 "Yes"), the judgment unit 13 determines that no arc fault has occurred (S7). On the other hand, if the frequency of communication anomalies in any of the devices 3 at judgment time t1 is greater than the threshold (S6 "No"), the judgment unit 13 determines that an arc fault has occurred (S8). Processing S3 to S8 corresponds to judgment step ST3 of the arc detection method.

[0063] If the determination unit 13 determines that an arc fault has occurred (S8), the stop unit 15 stops the power supply from the power source 2 to the feeder line L1 by stopping the current flowing in the feeder line L1 (S9). Then, the notification unit 14 notifies that an arc fault has occurred (S10). On the other hand, if the determination unit 13 determines that no arc fault has occurred (S7), the processing of the arc detection system 100 ends. Hereinafter, the above series of processes S1 to S10 are repeated.

[0064] [advantage]

[0065] Hereinafter, the advantages of the arc detection system 100 according to the embodiment will be explained while comparing it with the comparative arc detection system. The comparative arc detection system differs from the arc detection system 100 according to the embodiment in that it does not have a second acquisition unit 12. That is, the comparative arc detection system differs from the arc detection system 100 according to the embodiment in that it immediately determines that an arc fault has occurred when a specific frequency band component in the measurement result of the current I1 obtained by the first acquisition unit 11 reaches a first predetermined value or above.

[0066] First, the conditions required for an arc detection system will be explained. If an arc occurs due to a break or near break in the feeder line L1, ignoring this situation could lead to a fire due to excessive heating of the broken or near-broken section, which may sometimes generate sparks. Therefore, it is crucial that the arc detection system can quickly detect the occurrence of an arc (i.e., an arc fault) and stop supplying power to the feeder line L1 before a fire occurs. For example, the UL (Underwriters Laboratories) standard requires detection of an arc fault within two seconds of its occurrence.

[0067] Even in a comparative arc detection system, the occurrence of arc faults can be detected. However, this system misclassifies arcing not only as a result of a broken or nearly broken feeder line L1, but also as an arc caused by contact chatter. In other words, the comparative arc detection system incorrectly identifies arcing as a fault even when the occurrence of an arc is unlikely to be the cause.

[0068] Furthermore, in the comparative arc detection system, an arc fault is also detected even when the load 31 of device 3 experiences a sudden change. In other words, the comparative arc detection system incorrectly identifies an arc fault even when no arc has actually occurred. Thus, because the comparative arc detection system detects an arc fault every time an arc occurs or every sudden change in load 31 occurs, users may find it inconvenient to use. For example, there is a possibility that the user is notified of an arc fault every time device 3 is connected to or disconnected from the feeder line L1, or every time the power to device 3 is turned on / off, which would be annoying for the user. Furthermore, assuming the comparative arc detection system is configured to automatically stop supplying power from power source 2 to feeder line L1 when an arc fault is detected, this configuration could also result in the power supply to feeder line L1 being stopped every time device 3 is connected to or disconnected from the feeder line L1, or every time the power to device 3 is turned on / off, which would also be annoying for the user.

[0069] On the other hand, in the arc detection system 100 according to the embodiment, since a second acquisition unit 12 is provided, the determination unit 13 can grasp the degree of quality of power line communication with the device 3. Here, the quality of power line communication via the feeder line L1 is affected by the state of the feeder line L1. Specifically, if the feeder line L1 is not in an aged state, the degree of quality of power line communication will be higher; conversely, if the feeder line L1 is in an aged state, the degree of quality of power line communication will be lower. Furthermore, when the feeder line L1 tends to age and a part of it is broken or almost broken, the frequency of communication abnormalities is above a threshold and the greater it is than the threshold, the lower the degree of quality of power line communication. In other words, the determination unit 13 can determine whether a break or almost breakage is likely to occur in the feeder line L1 by grasping the degree of quality of power line communication with the device 3.

[0070] Therefore, in the arc detection system 100 according to the embodiment, if an arc occurs due to a break or near break of the feeder line L1, it is determined that an arc fault has occurred. Otherwise, it is generally not determined that an arc fault has occurred.

[0071] In other words, in the arc detection system 100 according to the embodiment, the likelihood of judging an arc fault as occurring is low when an arc is caused by contact jitter or when there is a sharp change in the load 31. In other words, the arc detection system 100 according to the embodiment has the advantage of easily preventing the erroneous detection of arc faults caused by contact jitter or sharp changes in the load 31, thus easily preventing false detection of arc faults. Therefore, the phenomena that may occur in the comparative arc detection system are unlikely to occur in the arc detection system 100 according to the embodiment. That is, in the arc detection system 100 according to the embodiment, since the user is notified or power supply to the feeder line L1 is stopped only when a phenomenon considered to have a significant impact on the user occurs, i.e., when an arc fault occurs, it has the advantage of being convenient for the user to use.

[0072] (Modified Example)

[0073] While the embodiments have been described above, the present invention is not limited to these embodiments. Hereinafter, variations of the embodiments are listed. The variations described below can also be appropriately combined.

[0074] In some embodiments, although the ammeter 22 is configured as a different device from the arc detection system 100, it may also be built into the arc detection system 100.

[0075] In this embodiment, although the second acquisition unit 12 and the operating device 3 connected to the feed line L1 communicate at regular intervals, this is not a limitation. For example, the second acquisition unit 12 may also communicate with the device 3 intermittently. For example, if the number of times the second acquisition unit 12 sends a request signal to the device 3 per unit time is fixed, the interval between sending the request signal per unit time may also be intermittent.

[0076] In this embodiment, although the arc detection system 100 is provided in the power supply 2, it is not limited thereto. For example, the arc detection system 100 may also be connected to the feeder line L1 as a device different from the power supply 2. In this case, as long as the arc detection system 100 is configured to communicate with the power supply 2 via wired communication, wireless communication, or power line communication, it can provide the power supply 2 with an indication corresponding to the judgment result of the judgment unit 13.

[0077] In this embodiment, although the determination unit 13 extracts components of a specific frequency band by performing frequency analysis on the measurement result of the current I1 obtained by the first acquisition unit 11, it is not limited to this. For example, the determination unit 13 may also extract frequency components of a specific frequency band by passing the measurement result of the current I1 obtained by the first acquisition unit 11 through a filter (e.g., a bandpass filter) instead of performing frequency analysis.

[0078] In this embodiment, while the first acquisition unit 11 obtains the measurement result of the current I1, it can also obtain the measurement result of the voltage V1. In this case, the first acquisition unit 11 obtains the measurement result of the measured voltage V1 by using a voltmeter instead of the ammeter 22 to perform sampling measurements at a predetermined period (sampling period). That is, the first acquisition unit 11 obtains the measurement result of the voltage V1 at the predetermined period from the voltmeter. The voltmeter is installed in the power supply 2 to measure the line voltage (i.e., the voltage V1 in the feed line L1) between the feed line on the positive side and the feed line on the negative side of the feed line L1. Alternatively, the voltmeter may not be installed in the power supply 2, and may be configured as a device different from the power supply 2.

[0079] Furthermore, in this case, the determination unit 13 determines whether an arc has occurred based on the components of a specific frequency band in the voltage V1 measurement result obtained by the first acquisition unit 11. Specifically, the determination unit 13 performs frequency analysis on the voltage V1 measurement result obtained by the first acquisition unit 11. Then, by referring to the calculated spectrum, the determination unit 13 determines that an arc has occurred if the voltage V1 measurement result includes components of a specific frequency band above a first predetermined value. The specific frequency band is, for example, a frequency band that includes the frequency of noise generated in the event of an arc fault. As an example, the specific frequency band is tens of kHz, which is a relatively high frequency band. In addition, the frequency of the noise generated in the above case can be determined experimentally.

[0080] In this embodiment, although the second acquisition unit 12 is separately installed from the power supply 2 in the communication module 20 connected to the feed line L1, it is not limited to this. For example, the second acquisition unit 12 may also be installed in the power supply 2. In this case, the communication module 20 is not required in the arc detection system 100.

[0081] In this embodiment, although the determination unit 13 determines that an arc fault has occurred if the duration of the determination that an arc has occurred is above a second threshold (threshold time Th1), it is not limited to this. For example, the determination unit 13 may determine that an arc fault has occurred if the component of a specific frequency band included in the measurement result is above a second predetermined value (greater than a first predetermined value), regardless of the variation information obtained by the second acquisition unit 12.

[0082] In this embodiment, the feeder line L1 may also be connected to multiple devices 3. In this case, the determination unit 13 can estimate to some extent where an arc fault has occurred on the feeder line L1 by referring to the quality information of each of the multiple devices 3. That is, the determination unit 13 can also estimate the location of the arc fault based on the quality information of each of the multiple devices 3 obtained by the second acquisition unit 12 when it is determined that an arc fault has occurred.

[0083] For example, suppose device 3, referred to as "A", and device 3, referred to as "B", are connected to feeder line L1. Furthermore, if the determination unit 13 determines that an arc fault has occurred, it assumes that the frequency of communication anomalies in device 3, referred to as "A", is lower than a threshold, and the frequency of communication anomalies in device 3, referred to as "B", is higher than a threshold. In this case, the determination unit 13 estimates that an arc fault has occurred between the connection points of device 3, referred to as "A", and device 3, referred to as "B", in feeder line L1.

[0084] In this implementation, although the stopping unit 15 stops the current flowing in the feeder line L1 when the determination unit 13 determines that an arc fault has occurred, it is not limited to this. For example, the stopping unit 15 may also be configured to shut off the power supply to the device 3 separately when the determination unit 13 determines that an arc fault has occurred. For example, if the device 3 is equipped with a DC / DC converter circuit, the stopping unit 15 can implement this by sending a command to the device 3 to shut down the switching element of the DC / DC converter circuit. In this manner, it is possible to maintain the operation of other devices 3 while only cutting off the power supply to the device 3 related to the arc fault.

[0085] In this implementation, although the arc detection system 100 is used in a DC distribution network 200, it is not limited to this. For example, the arc detection system 100 can also be used in an AC distribution network. In this case, the power source 2 is an AC power source.

[0086] For example, the present invention can be implemented not only as an arc detection system 100, but also as an arc detection method including the steps (processes) performed on each constituent element constituting the arc detection system 100.

[0087] Specifically, the arc detection method includes a first acquisition step ST1, a second acquisition step ST2, and a judgment step ST3. In the first acquisition step ST1, the measurement results of current I1 or voltage V1 are obtained. Current I1 is the current flowing in the feeder line L1, which is powered by power source 2, and voltage V1 is the voltage in the feeder line L1. In the second acquisition step ST2, quality information related to the quality of communication between the feeder line L1 and the device 3 connected to the feeder line L1 is obtained through power line communication. In the judgment step ST3, a judgment is made as to whether an arc fault has occurred in the feeder line L1, based on the specific frequency band components in the measurement results obtained in the first acquisition step ST1 and the quality information obtained in the second acquisition step ST2.

[0088] For example, these steps can also be performed by a computer (computer system) having more than one processor. Furthermore, the present invention can be implemented as a program for causing a computer to execute the steps included in these methods. Further, the present invention can also be implemented by a non-transitory recording medium such as a CD-ROM, which is a computer-readable recording program. Specifically, the program causes more than one processor to execute the above-described arc detection method.

[0089] Although at least a portion of the arc detection system 100 described in the above embodiments is implemented by microcomputer-executed software, it can also be implemented by executing software on a general-purpose computer such as a personal computer. Furthermore, at least a portion of the arc detection system 100 can also be implemented by hardware consisting of dedicated electronic circuits such as A / D converters, logic circuits, gate arrays, and D / A converters.

[0090] Furthermore, the forms obtained by performing various modifications that can be conceived by those skilled in the art on various embodiments, as well as the forms achieved by arbitrarily combining the constituent elements and functions of various embodiments without departing from the spirit of the present invention, are all included within the scope of the present invention.

[0091] (Summarize)

[0092] As described above, the arc detection system 100 includes a first acquisition unit 11, a second acquisition unit 12, and a determination unit 13. The first acquisition unit 11 acquires measurement results of current I1 or voltage V1, where current I1 is the current flowing in the feeder line L1 powered by the power source 2, and voltage V1 is the voltage in the feeder line L1. The second acquisition unit 12 obtains quality information related to the quality of communication between the feeder line L1 and the device 3 connected to the feeder line L1 through power line communication. The determination unit 13 determines whether an arc fault has occurred in the feeder line L1 based on the components of a specific frequency band in the measurement results acquired by the first acquisition unit 11 and the quality information acquired by the second acquisition unit 12.

[0093] Such an arc detection system 100 has the following advantages: it can easily prevent the arc generated when the device 3 is installed or removed from the feeder line L1 and the load 31 from changing drastically, thus preventing false detection of arc faults.

[0094] For example, in the arc detection system 100, if the determination unit 13 determines that an arc has occurred based on the measurement results obtained by the first acquisition unit 11, and the frequency of communication abnormalities obtained by the second acquisition unit 12 during the determination time is above a threshold, then the arc fault has occurred.

[0095] Such an arc detection system 100 has the following advantages: since the broken or nearly broken feeder line L1 can be easily detected by referring to the frequency of communication anomalies, it is easy to prevent false detection of arc faults.

[0096] For example, in the arc detection system 100, if the judgment unit 13 determines that an arc has occurred based on the measurement results obtained by the first acquisition unit 11 and the time of determination is above the threshold time Th1, the judgment unit 13 determines that an arc fault has occurred regardless of the quality information obtained by the second acquisition unit 12.

[0097] Such an arc detection system 100 has the following advantages: compared with the case of referring to quality information, it is easier to detect arc faults at an earlier stage.

[0098] For example, in the arc detection system 100, the feeder line L1 is connected to multiple devices 3. When the determination unit 13 determines that an arc fault has occurred, it estimates the location of the arc fault based on the quality information of each of the multiple devices 3 obtained by the second acquisition unit 12.

[0099] Such an arc detection system 100 has the following advantages: since it can estimate the location of an arc fault, it is easy to take measures to address the occurrence of the arc fault.

[0100] Furthermore, the arc detection method includes, for example, a first acquisition step ST1, a second acquisition step ST2, and a judgment step ST3. In the first acquisition step ST1, the measurement results of current I1 or voltage V1 are obtained. Current I1 is the current flowing in the feeder line L1, which is powered by the power source 2, and voltage V1 is the voltage in the feeder line L1. In the second acquisition step ST2, quality information related to the quality of communication with the device 3 is obtained by power line communication via the feeder line L1 and the device 3 connected to the feeder line L1. In the judgment step ST3, a judgment is made as to whether an arc fault has occurred in the feeder line L1, based on the specific frequency band components in the measurement results obtained in the first acquisition step ST1 and the quality information obtained in the second acquisition step ST2.

[0101] This arc detection method has the following advantages: it easily prevents the arc generated when the device 3 is installed and removed from the feeder line L1 and the load 31 from changing drastically, thus preventing false detection of arc faults.

[0102] Furthermore, the program recording medium may contain, for example, a program that enables one or more processors to execute the aforementioned arc detection method.

[0103] Such a recording medium has the following advantages: it easily prevents the arc generated when the device 3 is installed or removed from the feeder line L1 and the sudden change in load 31 from being mistakenly detected as an arc fault, thus easily preventing false detection of arc faults.

[0104] Symbol Explanation

[0105] 11 First Acquisition Department

[0106] 12 Second Acquisition Department

[0107] 13 Judgment Department

[0108] 2 Power Supply

[0109] 3 Equipment

[0110] 100 Arc Detection System

[0111] I1 current

[0112] L1 feeder line

[0113] ST1 First Acquisition Step

[0114] ST2 Second Acquisition Step

[0115] ST3 Judgment Steps

[0116] V1 voltage

Claims

1. An arc detection system, comprising: The first obtaining unit obtains a measurement result of current or voltage, wherein the current is the current flowing in a feeder line powered by a power source, and the voltage is the voltage in the feeder line; The second acquisition unit obtains quality information related to the quality of communication between the devices by performing power line communication via the feeder and the device connected to the feeder. as well as The determination unit determines whether an arc fault has occurred in the feeder line based on the components of a specific frequency band in the measurement results obtained by the first acquisition unit and the quality information obtained by the second acquisition unit.

2. The arc detection system as described in claim 1, The second acquisition unit acquires the frequency of communication anomalies as the quality information. The determination unit determines that an arc fault has occurred if it determines that an arc has occurred based on the measurement result obtained by the first acquisition unit, and the frequency of the communication abnormality obtained by the second acquisition unit during the determination time is above a threshold.

3. The arc detection system as described in claim 1 or 2, If the time for determining that an arc has occurred based on the measurement result obtained by the first obtaining unit is greater than a threshold time, the determining unit determines that an arc fault has occurred regardless of the quality information obtained by the second obtaining unit.

4. The arc detection system as described in claim 1 or 2, The feeder cable is connected to multiple of the aforementioned devices. When the determination unit determines that the arc fault has occurred, it estimates the location of the arc fault based on the quality information of each of the plurality of devices obtained by the second acquisition unit.

5. An arc detection method, comprising: The first obtaining step is to obtain a measurement result of current or voltage, wherein the current is the current flowing in the feeder line that is powered by the power source, and the voltage is the voltage in the feeder line; The second obtaining step involves obtaining quality information related to the quality of communication between the devices by performing power line communication via the feeder and the devices connected to the feeder. as well as The judgment step involves determining whether an arc fault has occurred in the feeder line based on the specific frequency band components in the measurement results obtained in the first obtaining step and the quality information obtained in the second obtaining step.

6. A program recording medium, The program recording medium records a program that causes one or more processors to execute the arc detection method of claim 5.

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