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

Abstract

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 the measurement results of the current (I1) flowing through the power supply path (L1) supplied with power from the power source (2) or the voltage (V1) in the power supply path (L1). The second acquisition unit (12) acquires operation information related to the operation of the device (3) connected to the power supply path (L1). The determination unit (13) determines whether an arc fault has occurred in the power supply path (L1) based on the measurement results acquired by the first acquisition unit (11) and the operation information acquired by the second acquisition unit (12).

Description

Technical Field

[0001] This invention relates to an arc detection system, arc detection method, and program recording medium for determining whether there is a possibility of an arc fault occurring in a power supply path. Background Technology

[0002] Patent Document 1 discloses an arc detection unit for detecting electric arcs. This arc detection unit includes a voltage detection unit and a current detection unit. The voltage detection unit measures the voltage between the input-side wiring to the terminal block and the output-side wiring from the terminal block, and the current detection unit measures the current from the output-side wiring of the terminal block. Furthermore, this arc detection unit identifies electrical noise and electric arcs in 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] Prior art 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, arc detection method, and program recording medium that easily prevent false detections of arc faults.

[0008] Problem-solving methods

[0009] An arc detection system according to one aspect of the present invention includes a first acquisition unit, a second acquisition unit, and a determination unit. The first acquisition unit acquires measurement results of current flowing in a power supply path from which power is supplied, or of voltage in the power supply path. The second acquisition unit acquires operational information related to the operation of a device connected to the power supply path. The determination unit determines, based on the measurement results acquired by the first acquisition unit and the operational information acquired by the second acquisition unit, whether an arc fault has occurred in the power supply path.

[0010] An arc detection method according to one aspect of the present invention includes a first acquisition step, a second acquisition step, and a determination step. In the first acquisition step, a measurement result of the current flowing in a power supply path from which power is supplied, or the voltage in the power supply path, is acquired. In the second acquisition step, operational information related to the operation of a device connected to the power supply path is acquired. In the determination step, based on the measurement result acquired in the first acquisition step and the operational information acquired in the second acquisition step, it is determined whether an arc fault has occurred in the power supply path.

[0011] In one aspect of the present invention, a program recording medium records a program for executing the arc detection method by one or more processors.

[0012] The effects of the invention

[0013] According to one aspect of the present invention, it has the advantage of easily preventing false detections of arc faults. Attached Figure Description

[0014] Figure 1 This is a schematic diagram showing the overall structure of the arc detection system including Embodiment 1.

[0015] Figure 2A This is a timing diagram showing the first determination example of the determination unit of the arc detection system in Embodiment 1.

[0016] Figure 2B This is a timing diagram showing the second determination example of the determination unit of the arc detection system in Embodiment 1.

[0017] Figure 2C This is a timing diagram showing the third determination example of the determination unit of the arc detection system in Embodiment 1.

[0018] Figure 3 This is a flowchart illustrating an example of the operation of the arc detection system in Implementation Method 1.

[0019] Figure 4 This is a schematic diagram showing the overall structure of the arc detection system including Embodiment 2. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below represent specific examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement positions of constituent elements, connection methods, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0021] Furthermore, the figures are schematic diagrams and not necessarily rigorous illustrations. Also, in each figure, substantially identical structures are labeled with the same reference numerals, and repetitive descriptions are omitted or simplified.

[0022] (Implementation Method 1)

[0023] [structure]

[0024] use Figure 1 The arc detection system of Implementation Method 1 will be described. Figure 1 This is a schematic diagram showing the overall structure of the arc detection system 100 including Embodiment 1.

[0025] The arc detection system 100 is used to determine whether an arc fault has occurred in the power supply path L1, which is mainly supplied with power from the power source 2. That is, the power supply path L1 may be damaged or broken due to external factors or aging over time, and such damage may generate an arc (arc discharge), resulting in an arc fault. Therefore, the arc detection system 100 is mainly used to detect arc faults that may occur in the power supply path L1.

[0026] 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 power supply paths L1. Figure 1 Only one power supply path L1 is shown in the diagram. DC power is supplied from the power source (in this case, a DC power source) 2 to the DC distribution network 200. Each power supply path L1 consists of a pair of circuits: a positive power supply path connected to the positive terminal of the output side of the power source 2, and a negative power supply path connected to the negative terminal of the output side of the power source 2.

[0027] Here, when the DC distribution network 200 has only one power supply path L1, DC power is supplied from the power source 2 to that power supply path L1. Alternatively, when the DC distribution network 200 has multiple power supply paths L1, each of the multiple power supply paths L1 is connected at one or more branch points. Therefore, when DC power is supplied from the power source 2 to a certain power supply path L1, DC power is also supplied to other power supply paths L1 via one or more branch points.

[0028] In Embodiment 1, the power source 2 is a power converter equipped with an AC / DC converter 21. The power source 2 converts the AC power output from the power system 300 into DC power, and outputs the converted DC power to the power supply path L1 connected to the power source 2. When the DC distribution network 200 has multiple power supply paths L1, the DC power output to that power supply path L1 is also output to other power supply paths L1. In Embodiment 1, the power source 2 can be any type of power source that outputs DC power, and can also 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).

[0029] Each power supply path L1 is, for example, formed by a duct rail, and can accommodate more than one device 3. That is, more than one device 3 can be arranged in a free position in each power supply path L1. Of course, each power supply path L1 can also be arranged in a way that predetermines the location where more than one device 3 can be installed. In embodiment 1, each power supply path L1 is arranged on the ceiling of the facility, but it can also be arranged on the floor, wall, or other objects of the facility.

[0030] 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 while device 3 is in operation. That is, in Embodiment 1, when device 3 is connected to the power supply path L1, device 3 can communicate with the second acquisition unit 12; however, when device 3 is not connected to the power supply path L1, device 3 cannot communicate with the second acquisition unit 12.

[0031] Device 3 can be installed on or removed from power supply path L1 via a pair of connecting terminals. Specifically, when device 3 is installed on power supply path L1, with the pair of connecting terminals of device 3 inserted into the pipe rail (power supply path L1), device 3 can be rotated clockwise or counterclockwise by a predetermined angle (e.g., 90 degrees) when viewed from the insertion direction. This fixes the pair of connecting terminals in contact with a pair of connecting conductors provided on power supply path L1, thus electrically and mechanically connecting device 3 to power supply path L1.

[0032] With device 3 removed from power supply path L1, viewed from the insertion direction of device 3, rotate device 3 by a predetermined angle in the opposite direction. This releases the contact between a pair of connecting terminals and a pair of connecting conductors, allowing device 3 to be removed from power supply path L1. With device 3 installed in power supply path L1, load 31 is driven by DC power supplied from power source 2 via power supply path L1.

[0033] In Embodiment 1, device 3 is a lighting fixture, but it can also be, for example, a speaker, camera, sensor, or USB PD (Power Delivery). That is, device 3 can be any device other than a lighting fixture, as long as it is powered by the load 31. Furthermore, in Embodiment 1, all devices 3 connected to each power supply path L1 are of the same type of lighting fixture, but the types of devices 3 connected to each power supply path L1 can be multiple. For example, lighting fixtures, speakers, cameras, sensors, and USB PDs can be connected to each power supply path L1. These devices 3 can be all connected to one power supply path L1, or they can be connected separately to multiple power supply paths L1.

[0034] The arc detection system 100 includes a first acquisition unit 11, a second acquisition unit 12, a determination unit 13, a notification unit 14, and a stop unit 15, serving as functional components for determining whether an arc fault has occurred. In Embodiment 1, the first acquisition unit 11, the determination 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 provided in a communication module 20 that is connected separately to the power supply path L1 from the power supply 2. The communication module 20 is configured to communicate with the power supply 2 via, for example, wireless communication or power line communication (PLC).

[0035] In both the power supply 2 and the communication module 20, the arc detection system 100 is, for example, a microcomputer or a device equipped with a microcomputer. The microcomputer is a semiconductor integrated circuit, etc., having ROM and RAM storing programs, a processor (CPU: Central Processing Unit) for executing programs, a timer, an A / D converter, and a D / A converter, etc. The first acquisition unit 11, the second acquisition unit 12, the determination unit 13, the notification unit 14, and the stop unit 15 are all implemented by the processor executing the aforementioned programs.

[0036] The first acquisition unit 11 acquires the measurement results of the current I1 flowing in the power supply path L1 from the power source 2 or the voltage V1 in the power supply path L1. In Embodiment 1, the first acquisition unit 11 acquires the measurement results of the current I1 measured by sampling by the ammeter 22 at a predetermined period (sampling period). That is, the first acquisition unit 11 acquires the measurement results of the current I1 from the ammeter 22 at a predetermined period. The ammeter 22 is provided between the power source 2 and the power supply path L1, and measures the current flowing in the negative side of the power supply path L1 (i.e., the current I1 flowing in the power supply path L1). Alternatively, the ammeter 22 may be built into the power source 2.

[0037] The second acquisition unit 12 acquires operation information related to the operation of the device 3 connected to the power supply path L1. Here, the operation information may include information directly or indirectly indicating whether the load 31 of the device 3 receives power and operates. In Embodiment 1, the operation information indicates the communication status with the device 3. That is, if the second acquisition unit 12 receives a signal from the device 3 and can communicate with it, it acquires operation information that the device 3 is connected to the power supply path L1 and is operating. On the other hand, if it does not receive a signal from the device 3 and cannot communicate with it, the second acquisition unit 12 acquires operation information that the device 3 is not connected to the power supply path L1 and is not operating. The communication standard between the second acquisition unit 12 and the device 3 is not particularly limited. Furthermore, the communication between the second acquisition unit 12 and the device 3 can be wired communication, wireless communication, or power line communication.

[0038] In Embodiment 1, the second acquisition unit 12 communicates with the device 3, which operates connected to the power supply path L1, at a certain period (e.g., several hundred ms). For example, the second acquisition unit 12 may also communicate with the device 3 by receiving a signal unilaterally transmitted from the device 3, which operates connected to the power supply path L1. Alternatively, for example, the second acquisition unit 12 may broadcast a request signal containing an instruction to request a reply and receive a response signal from the device 3 that received the request signal, thereby communicating with the device 3.

[0039] Furthermore, the signal sent from device 3 to the second acquisition unit 12 includes identification information of the sending device 3. Therefore, the arc detection system 100 can grasp the operation information (here, the communication status) of each device 3.

[0040] The determination unit 13 determines whether an arc fault has occurred in the power supply path L1 based on the components of a specific frequency band in the measurement results obtained by the first acquisition unit 11 and the operation 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 determines that an arc has occurred if the measurement results of the current I1 contain components of a specific frequency band above a first predetermined value, referring to the calculated spectrum. The specific frequency band is, for example, a frequency band containing the frequency of noise generated when an arc has occurred. As an example, the specific frequency band is a band of 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.

[0041] Then, 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 on the power supply path L1 by referring to the operation information obtained by the second acquisition unit 12. That is, the determination unit 13 determines that an arc has occurred only based on the measurement results obtained by the first acquisition unit 11, and does not determine that an arc fault has occurred on the power supply path L1. The process of determining the occurrence of an arc fault in this way will be explained below.

[0042] Arcs that may occur in the DC distribution network 200 include arcs caused by a break or partial break in the power supply path L1, and arcs that may occur momentarily when installing or removing equipment 3 from the power supply path L1. Specifically, if the installation of equipment 3 is not successful when it is installed on the power supply path L1, the load 31 of equipment 3 may repeatedly switch between being connected to the power supply path L1 and disconnected from it for a short period, resulting in what is known as chattering. Furthermore, during the chattering process, an arc may occur when the load 31 is momentarily disconnected from the power supply path L1 while current is flowing. Similarly, chattering may also occur when equipment 3 is removed from the power supply path L1. Moreover, during the chattering process, an arc may occur when the load 31 is momentarily disconnected from the power supply path L1 while current is flowing. Such arcs caused by chattering can occur not only in the DC distribution network 200 but also in AC (Alternating Current) distribution networks. In particular, when the device 3 is installed on the power supply path L1 with the distance between the electrode of the device 3 and the electrode of the power supply path L1 incomplete, the electric arc is difficult to extinguish.

[0043] Here, arcs caused by breaks or partial breaks in the power supply path L1 are often the cause of arc faults, but arcs caused by vibrations are generally extinguished within a short time and are therefore unlikely to be the cause of arc faults. Therefore, in the arc detection system 100, it is desirable not to detect short-lived arcs caused by vibrations, but to primarily determine the occurrence of arcs caused by breaks or partial breaks in the power supply path L1 as the cause of arc faults.

[0044] Therefore, in Embodiment 1, to meet the above requirements, the determination unit 13 determines whether an arc fault has occurred in the power supply path 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 arc. If the duration is less than a first threshold, the determination unit 13 determines that no arc fault has occurred in the power supply path L1, regardless of the operation information (communication state) obtained by the second acquisition unit 12. Furthermore, if the duration is greater than or equal to the first threshold and less than the second threshold, the determination unit 13 determines whether an arc fault has occurred in the power supply path L1, as in the first or second determination example described below. Additionally, if the duration is greater than or equal to the second threshold, the determination unit 13 determines whether an arc fault has occurred in the power supply path L1, as in the third determination example described below. The first and second thresholds are, for example, preset by the user of the arc detection system 100.

[0045] Figure 2A This is a timing diagram showing the first determination example of the determination unit 13 of the arc detection system 100 in Embodiment 1. Figure 2B This is a timing diagram showing a second determination example of the determination unit 13 of the arc detection system 100 in Embodiment 1. Figure 2C This is a timing diagram showing a third determination example of the determination unit 13 of the arc detection system 100 in Embodiment 1. Figures 2A to 2C In each of the diagrams, the pulse representation in the upper timing diagram indicates the duration at which the determination unit 13 determines that an electric arc has occurred. Furthermore, in... Figures 2A to 2C In each of the diagrams, the pulses in the timing diagram below represent signals received from device 3 by the second acquisition unit 12.

[0046] like Figure 2A As shown, in the first determination example, before the determination unit 13 determines, based on the measurement results obtained by the first acquisition unit 11, that an arc has occurred (hereinafter also referred to as the "determination time point") t1, the second acquisition unit 12 periodically receives signals from the device 3. On the other hand, in the first determination example, after the determination time point t1, the second acquisition unit 12 fails to receive signals from the device 3.

[0047] Therefore, in the first determination example, before and after determination time point t1, the communication status obtained by the second acquisition unit 12 changes from "able to communicate" to "unable to communicate," thus determining that device 3 was removed from power supply path L1 at determination time point t1. Then, determination unit 13 determines that the generated arc is an arc caused by vibration, and no arc fault occurred in power supply path L1. On the other hand, if the communication status obtained by the second acquisition unit 12 before and after determination time point t1 is still "able to communicate," then determination unit 13 determines that an arc caused by a break or partial break in power supply path L1 has occurred, i.e., an arc fault has occurred.

[0048] like Figure 2B As shown, in the second determination example, the second acquisition unit 12 fails to receive a signal from the device 3 before the determination time point t1. On the other hand, in the second determination example, signals from the device 3 are received periodically after the determination time point t1.

[0049] Therefore, in the second determination example, the determination unit 13 determines that the device 3 is installed in the power supply path L1 at the determination time t1, based on the change in communication status from "cannot communicate" to "can communicate" obtained by the second acquisition unit 12 before and after the determination time t1. Then, the determination unit 13 determines that the generated arc is an arc caused by vibration, and no arc fault has occurred in the power supply path L1. On the other hand, if the communication status obtained by the second acquisition unit 12 before and after the determination time t1 is still "cannot communicate", the determination unit 13 determines that an arc caused by a break or partial break in the power supply path L1 has occurred, that is, an arc fault has occurred.

[0050] Thus, in the first and second determination examples, if the determination is based on the measurement results obtained by the first acquisition unit 11 and it is determined that an arc has occurred, and the communication status shown in the operation information before and after the determination has changed, the determination unit 13 determines that no arc fault has occurred.

[0051] like Figure 2C As shown, in the third determination example, the determination unit 13 determines that the duration of the arc is longer than the second threshold (threshold time Th1). Furthermore, in the third determination example, the determination unit 13 determines that an arc caused by a break or partial break in the power supply path L1 has occurred, i.e., an arc fault has occurred, without referring to the communication status obtained by the second acquisition unit 12. Thus, when the determination unit 13 determines that the duration of the arc is greater than or equal to the second threshold (threshold time Th1) based on the measurement results obtained by the first acquisition unit 11, it determines that an arc fault has occurred without relying on the operation information obtained by the second acquisition unit 12.

[0052] The notification unit 14 can notify the surrounding area of ​​an arc fault, for example, by turning on a light or sounding a buzzer. Alternatively, the notification unit 14 can notify the owner or administrator of the arc detection system 100 of an arc fault by sending information indicating an arc fault to their information terminal. As an example, the information terminal could include portable terminals such as smartphones or tablets, as well as personal computers.

[0053] If the determination unit 13 determines that an arc fault has occurred, the stopping unit 15 stops the current flowing in the power supply path L1. Thus, if an arc discharge occurs due to the arc fault, the arc discharge is extinguished.

[0054] For example, the stop unit 15 stops the current flowing in the power supply path L1 by controlling a switch connected to the power supply path L1. The switch can be, for example, a mechanical switch or a semiconductor switch. A mechanical switch is, for example, a relay or a circuit breaker, while a semiconductor switch is, for example, a transistor or a diode.

[0055] Furthermore, the switch connected to the power supply path L1 can be either directly or indirectly connected to the power supply path L1. 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 power supply path L1, it is indirectly connected to the power supply path L1, thus the switch is connected to the power supply path L1. For example, the stop unit 15 stops the switching operation of the switch by controlling the switch, thereby stopping the current flowing in the power supply path L1.

[0056] Alternatively, the switch can be configured to toggle the connection and disconnection of the power supply 2. In this case, the stop unit 15 controls the switch to disconnect the power supply 2, thereby stopping the current flowing in the power supply path L1.

[0057] Alternatively, a switch can be provided on the power supply path L1, and this switch can also be configured to switch the opening and closing of the power supply path L1. For example, the stop unit 15 can also open the power supply path L1 by controlling the switch, thereby stopping the current flowing in the power supply path L1.

[0058] [action]

[0059] The following uses Figure 3 An example of the operation of the arc detection system 100 of Embodiment 1 will be described. Figure 3 This is a flowchart illustrating an example of the operation of the arc detection system 100 according to Embodiment 1.

[0060] First, the first acquisition unit 11 acquires the measurement result of current I1 from the ammeter 22 at a predetermined period (S1). Processing S1 corresponds to the first acquisition step ST1 of the arc detection method. Next, the second acquisition unit 12 acquires the communication status (i.e., operation information) with each device 3 by waiting to receive signals from each device 3 (S2). Processing S2 corresponds to the second acquisition step ST2 of the arc detection method. Then, the determination unit 13 first determines whether an arc has been generated based on the components of a specific frequency band in the measurement result of current I1 acquired by the first acquisition unit 11 (S3). Here, the determination unit 13 determines this by performing frequency analysis on the measurement result of current I1 acquired by the first acquisition unit 11.

[0061] 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).

[0062] If an arc is detected, and the duration is less than a first threshold (S4: Yes), the determination unit 13 determines that no arc fault has occurred (S7). Conversely, if the duration is greater than or equal to a 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 monitors whether there are any changes in the communication status with each device 3 before and after the determination time point t1, referring to the communication status obtained by the second acquisition unit 12 (S6).

[0063] If the communication status with any device 3 changes before or after the determination time point t1 (S6: Yes), the determination unit 13 determines that no arc fault has occurred (S7). On the other hand, if the communication status with any device 3 remains unchanged before or after the determination time point t1 (S6: No), the determination unit 13 determines that an arc fault has occurred (S8). Processing S3 to S8 corresponds to determination step ST3 of the arc detection method.

[0064] If the determination unit 13 determines that an arc fault has occurred (S8), the stop unit 15 stops supplying power from the power source 2 to the power supply path L1 by stopping the current flowing in the power supply path 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.

[0065] [advantage]

[0066] Hereinafter, the advantages of the arc detection system 100 of Embodiment 1 will be explained in comparison with the arc detection system of the comparative example. The arc detection system of the comparative example differs from the arc detection system 100 of Embodiment 1 in that it does not have a second acquisition unit 12. That is, in the arc detection system of the comparative example, the difference from the arc detection system 100 of Embodiment 1 is that when a specific frequency band component in the measurement result of the current I1 acquired by the first acquisition unit 11 is above a first predetermined value, an arc fault is immediately determined to have occurred.

[0067] First, the conditions required for an arc detection system will be explained. In the event of an arc caused by a break or partial break in the power supply path L1, if left unattended, the broken or partial break will overheat, potentially leading to a fire. Therefore, it is crucial that the arc detection system quickly detects the occurrence of an arc (i.e., the occurrence of an arc fault) and stops supplying power to the power supply path L1 before it escalates into a fire. For example, the UL (Underwriters Laboratories) standard requires the detection of an arc fault within 2 seconds of its occurrence.

[0068] The comparative arc detection system can also detect the occurrence of arc faults. However, in the comparative arc detection system, not only when an arc is generated due to a break or partial break in the power supply path L1, but also when an arc is generated due to vibration, it is incorrectly identified as an arc fault. That is, in the comparative arc detection system, even if an arc is generated that is unlikely to be the cause of an arc fault, it is incorrectly identified as an arc fault. Thus, in the comparative arc detection system, every time an arc occurs, it is identified as an arc fault, which may reduce user convenience. For example, since a notification of an arc fault occurs every time device 3 is connected to or disconnected from the power supply path L1, it is inconvenient for the user. Furthermore, for example, suppose the system is configured to automatically stop the power supply from power source 2 to the power supply path L1 when an arc fault is detected. In this configuration, since the power supply to the power supply path L1 is stopped every time device 3 is connected to or disconnected from the power supply path L1, this is also inconvenient for the user.

[0069] On the other hand, in the arc detection system 100 of Embodiment 1, since a second acquisition unit 12 is provided, the determination unit 13 can determine whether the device 3 has been installed or removed by referring to the communication status (i.e., operation information) with the device 3. Therefore, in the arc detection system 100 of Embodiment 1, if an arc is generated due to a break or partial break in the power supply path L1, it is determined that an arc fault has occurred; if an arc is generated due to vibration, it is generally not determined that an arc fault has occurred.

[0070] That is, in the arc detection system 100 of Embodiment 1, the probability of determining that an arc fault has occurred based on the generation of an arc that is unlikely to cause an arc fault is low. In other words, in the arc detection system 100 of Embodiment 1, it is not necessary to detect phenomena that only occur temporarily and do not lead to arc faults, such as arcs that may occur when the device 3 is installed or removed from the power supply circuit L1. Therefore, it has the advantage of easily preventing false detections of arc faults. Thus, in the arc detection system 100 of Embodiment 1, the phenomena that may occur in the arc detection system of the comparative example are less likely to occur. That is, in the arc detection system 100 of Embodiment 1, it is possible to notify the user or stop the power supply to the power supply path L1 only when an arc fault that is considered to have a particularly large impact on the user occurs. Therefore, it has the advantage of good user convenience.

[0071] (Implementation Method 2)

[0072] [structure]

[0073] The following uses Figure 4 The arc detection system 100 of Embodiment 2 will be described. Figure 4 This is a schematic diagram showing the overall structure of the arc detection system 100 including Embodiment 2. In the arc detection system 100 of Embodiment 2, the function of the second acquisition unit 12A differs from the function of the second acquisition unit 12 in the arc detection system 100 of Embodiment 1. Furthermore, in the arc detection system 100 of Embodiment 2, the function of the determination unit 13A differs from the function of the determination unit 13 in the arc detection system 100 of Embodiment 1. In addition, in Embodiment 2, a device 3A equipped with a battery 32 can be connected to the power supply path L1, in addition to the device 3 in Embodiment 1. Hereinafter, the differences from Embodiment 1 will be mainly explained, and the commonalities with Embodiment 1 will be appropriately omitted.

[0074] Device 3A differs from device 3 in Embodiment 1 in that it includes a battery 32. Therefore, unlike device 3 in Embodiment 1, device 3A's communication function with the second acquisition unit 12A does not operate upon receiving power from the power supply path L1, but rather upon receiving power from the battery 32. Therefore, in Embodiment 2, device 3A can perform its communication function with the second acquisition unit 12A regardless of whether it is connected to the power supply path L1.

[0075] The second acquisition unit 12A differs from the second acquisition unit 12 in Embodiment 1 in that it also acquires, as operation information, whether the communication function between the devices 3 and 3A and the second acquisition unit 12A is driven by the battery 32. For example, the second acquisition unit 12A broadcasts a request signal containing a command to request drive information. Upon receiving the request signal, the device 3 sends a response signal containing drive information indicating that the battery 32 is not present to the second acquisition unit 12A. Conversely, upon receiving the request signal, the device 3A sends a response signal containing drive information indicating that the battery 32 is present to the second acquisition unit 12A. Then, the second acquisition unit 12A acquires the drive information indicating whether the device is driven by the battery 32 by receiving the response signal.

[0076] Furthermore, for example, when the user inputs drive information from devices 3 and 3A such as the controller or remote operation controller provided with the arc detection system 100, the second acquisition unit 12A can also acquire the input drive information. In this case, the second acquisition unit 12A can acquire drive information even without communicating with devices 3 and 3A.

[0077] The determination unit 13A differs from the determination unit 13 in Embodiment 1. When the communication function between device 3A and the second acquisition unit 12A is driven by the battery 32, it determines whether an arc fault has occurred in the power supply path L1 without referring to the communication status. That is, for device 3 which does not have a battery 32, the determination unit 13A, as in Embodiment 1, determines whether an arc fault has occurred by referring to the communication status obtained by the second acquisition unit 12A as needed. On the other hand, for device 3A which has a battery 32, the determination unit 13A does not refer to the communication status obtained by the second acquisition unit 12A, but only determines whether an arc fault has occurred based on the measurement results obtained by the first acquisition unit 11.

[0078] For example, if it is determined that the duration of the arc is greater than or equal to a first threshold but less than a second threshold, the determination unit 13A does not refer to the communication status obtained by the second acquisition unit 12A for the device 3A equipped with the battery 32. In this case, the determination unit 13A determines that an arc fault has occurred only if the duration is greater than or equal to the second threshold (threshold time Th1).

[0079] [advantage]

[0080] Like the arc detection system 100 of Embodiment 1, the arc detection system 100 of Embodiment 2 has the advantage of easily preventing false detections of arc faults. Furthermore, the arc detection system 100 of Embodiment 2 has the advantage that, when the communication function between device 3A and the second acquisition unit 12A is driven by battery 32, false detections of arc faults are easily prevented by not referring to the communication state. That is, device 3A, equipped with battery 32, can be driven by battery 32 even when not connected to the power supply path L1, and therefore can communicate with the arc detection system 100. Therefore, in the arc detection system 100 of Embodiment 1, if the communication state with device 3A is referenced, the determination unit 13 may incorrectly determine that an arc fault has occurred because the communication state has not changed. Therefore, in the arc detection system 100 of Embodiment 2, the determination unit 13A does not refer to the communication state when device 3A is driven by battery 32, thereby avoiding the incorrect determination of an arc fault as described above.

[0081] (Modified Example)

[0082] The embodiments 1 and 2 have been described above, but the present invention is not limited to the embodiments 1 and 2 described above. Hereinafter, variations of embodiments 1 and 2 are listed. The variations described below can also be appropriately combined.

[0083] In embodiments 1 and 2, the ammeter 22 is a device separate from the arc detection system 100, but it can be built into the arc detection system 100.

[0084] In embodiments 1 and 2, the second acquisition units 12 and 12A communicate with the devices 3 and 3A that operate via the power supply path L1 at fixed intervals, but are not limited to this. For example, the second acquisition units 12 and 12A may communicate with the devices 3 and 3A at irregular intervals.

[0085] In embodiments 1 and 2, the arc detection system 100 is installed at the power supply 2, but it is not limited thereto. For example, the arc detection system 100 may also be connected to the power supply path L1 as a device separate from the power supply 2. In this case, if the arc detection system 100 is configured to communicate with the power supply 2 via wired communication, wireless communication, or power line communication, the arc detection system 100 can provide the power supply 2 with an indication corresponding to the determination result of the determination units 13 and 13A.

[0086] In embodiments 1 and 2, the determination units 13 and 13A extract components of a specific frequency band by performing frequency analysis on the measurement results of the current I1 obtained by the first acquisition unit 11, but are not limited thereto. For example, the determination units 13 and 13A may also extract the frequency components of a specific frequency band by passing the measurement results of the current I1 obtained by the first acquisition unit 11 through a filter (e.g., a bandpass filter) instead of performing frequency analysis.

[0087] In embodiments 1 and 2, the first acquisition unit 11 acquires the measurement result of the current I1, but it can also acquire the measurement result of the voltage V1. In this case, the first acquisition unit 11 acquires the measurement result of the voltage V1, which is measured by sampling at a predetermined period (sampling period) using a voltmeter instead of the ammeter 22. That is, the first acquisition unit 11 acquires the measurement result of the voltage V1 from the voltmeter at a predetermined period. The voltmeter is installed in the power supply 2 and measures the line voltage between the positive and negative power supply paths of the power supply path L1 (i.e., the voltage V1 in the power supply path L1). Alternatively, the voltmeter may not be installed in the power supply 2, or it may be a device separate from the power supply 2.

[0088] Furthermore, in this case, the determination units 13 and 13A determine whether an electric 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 units 13 and 13A perform frequency analysis on the voltage V1 measurement result obtained by the first acquisition unit 11. Then, by referring to the calculated spectrum, the determination units 13 and 13A determine that an electric arc has occurred if the voltage V1 measurement result contains components of a specific frequency band above a first predetermined value. The specific frequency band is, for example, a band containing the frequency of noise generated in the event of an electric arc fault. As an example, the specific frequency band is a band of 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.

[0089] In embodiments 1 and 2, the second acquisition units 12 and 12A are provided in the communication module 20, which is connected to the power supply path L1 separately from the power supply 2, but are not limited thereto. For example, the second acquisition units 12 and 12A may be provided in the power supply 2. In this case, the communication module 20 is not required in the arc detection system 100.

[0090] In embodiments 1 and 2, if it is determined that the duration of the arc is greater than or equal to a second threshold (threshold time Th1), the determination units 13 and 13A determine that an arc fault has occurred without relying on the operation information obtained by the second acquisition units 12 and 12A, but are not limited thereto. For example, the determination units 13 and 13A may also determine that an arc fault has occurred without relying on the operation information obtained by the second acquisition units 12 and 12A if the components of a specific frequency band included in the measurement result contain a second predetermined value (> a first predetermined value).

[0091] In embodiments 1 and 2, the arc detection system 100 is used in a DC distribution network 200, but is not limited thereto. For example, the arc detection system 100 can be used in an AC distribution network. In this case, the power source 2 is an AC power source.

[0092] 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.

[0093] Specifically, the arc detection method includes a first acquisition step ST1, a second acquisition step ST2, and a determination step ST3. In the first acquisition step ST1, the measurement results of the current I1 flowing in the power supply path L1 from the power source 2, or the voltage V1 in the power supply path L1, are acquired. In the second acquisition step ST2, action information related to the operation of the device 3 connected to the power supply path L1 is acquired. In the determination step ST3, based on the measurement results acquired in the first acquisition step ST1 and the action information acquired in the second acquisition step ST2, it is determined whether an arc fault has occurred in the power supply path L1.

[0094] For example, these steps can be performed by a computer (computer system) having one or more processors. Furthermore, the present invention can be implemented as a program for causing a computer to perform the steps included in these methods. Moreover, the present invention can be implemented as a non-transitory computer-readable recording medium such as a CD-ROM containing the program. Specifically, the program causes one or more processors to execute the above-described arc detection method.

[0095] At least a portion of the arc detection system 100 described in each of the above embodiments is implemented in software using a microcomputer, but it can also be implemented in software using a general-purpose computer such as a personal computer. Furthermore, at least a portion of the arc detection system 100 can also be implemented in hardware using dedicated electronic circuits composed of A / D converters, logic circuits, gate arrays, D / A converters, etc.

[0096] Furthermore, this invention also includes various modifications to the embodiments that would be conceived by those skilled in the art, and methods implemented by arbitrarily combining the constituent elements and functions of the embodiments without departing from the spirit of the invention.

[0097] (Summarize)

[0098] As described above, the arc detection system 100 includes a first acquisition unit 11, second acquisition units 12 and 12A, and a determination unit 13 and 13A. The first acquisition unit 11 acquires the measurement results of the current I1 flowing in the power supply path L1 from the power supply 2 or the voltage V1 in the power supply path L1. The second acquisition units 12 and 12A acquire operation information related to the operation of the devices 3 and 3A connected to the power supply path L1. The determination units 13 and 13A determine whether an arc fault has occurred in the power supply path L1 based on the specific frequency band components in the measurement results acquired by the first acquisition unit 11 and the operation information acquired by the second acquisition units 12 and 12A.

[0099] According to such an arc detection system 100, since it does not need to detect phenomena that are only temporarily generated and will not cause arc faults, such as the arcs that may be generated when the equipment 3 and 3A are installed or removed from the power supply line L1, it has the advantage of easily preventing false detections of arc faults.

[0100] Furthermore, for example, in the arc detection system 100, the operation information indicates the communication status of devices 3 and 3A. If, based on the measurement results obtained by the first acquisition unit 11, it is determined that an arc has occurred, and the communication status shown in the operation information changes before and after the determination, the determination units 13 and 13A determine that no arc fault has occurred.

[0101] According to such an arc detection system 100, by referring to the communication status with devices 3 and 3A, it is easy to detect the installation and removal of devices 3 and 3A relative to the power supply path L1, thus having the advantage of easily preventing false detection of arc faults.

[0102] Additionally, for example, in the arc detection system 100, the second acquisition unit 12A also acquires drive information as operation information regarding whether the communication function between the devices 3 and 3A and the second acquisition unit 12A is driven by the battery 32. If the communication function between the device 3A and the second acquisition unit 12A is driven by the battery 32, the determination unit 13A determines whether an arc fault has occurred in the power supply path L1 without referring to the communication status.

[0103] According to such an arc detection system 100, since it does not refer to the communication status of the device 3A driven by the battery 32, it has the advantage of easily preventing false detection that the device 3A has not been installed or removed relative to the power supply path L1.

[0104] In addition, for example, in the arc detection system 100, if the determination units 13 and 13A determine that the time when an arc was generated is a threshold time Th1 or more based on the measurement results obtained by the first acquisition unit 11, they determine that an arc fault has occurred without relying on the operation information obtained by the second acquisition units 12 and 12A.

[0105] According to such an arc detection system 100, compared with the case of referring to action information, it has the advantage of being able to easily determine that an arc fault has occurred at an early stage.

[0106] Additionally, for example, the arc detection method includes a first acquisition step ST1, a second acquisition step ST2, and a determination step ST3. In the first acquisition step ST1, the measurement results of the current I1 flowing in the power supply path L1 from the power source 2, or the voltage V1 in the power supply path L1, are acquired. In the second acquisition step ST2, action information related to the operation of devices 3 and 3A connected to the power supply path L1 is acquired. In the determination step ST3, based on the measurement results acquired in the first acquisition step ST1 and the action information acquired in the second acquisition step ST2, it is determined whether an arc fault has occurred in the power supply path L1.

[0107] According to this arc detection method, since it is not necessary to detect arcs that may occur temporarily and do not lead to arc faults, such as those that may occur when equipment 3 and 3A are installed or removed from power supply line L1, it has the advantage of easily preventing false detections of arc faults.

[0108] Alternatively, for example, a program recording medium records a program that causes one or more processors to execute the above-described arc detection method.

[0109] According to such a recording medium, since it is not necessary to detect phenomena that are only temporarily generated and will not cause arc faults, such as the arc that may be generated when the equipment 3 and 3A are installed or removed from the power supply line L1, it has the advantage of easily preventing false detection of arc faults.

[0110] Explanation of reference numerals in the attached figures

[0111] 11 First Acquisition Department

[0112] 12, 12A Second Acquisition Section

[0113] 13. 13A Judgment Section

[0114] 2 power supplies

[0115] 3. 3A equipment

[0116] 32 batteries

[0117] 100 Arc Detection System

[0118] I1 current

[0119] L1 power supply path

[0120] ST1 First Acquisition Steps

[0121] ST2 Second Acquisition Step

[0122] ST3 Determination Steps

[0123] Th1 threshold time

[0124] V1 voltage

Claims

1. An arc detection system, wherein, have: The first acquisition unit acquires the measurement results of the current flowing in the power supply path from which power is supplied, or the voltage in the power supply path. The second acquisition unit acquires action information related to the operation of the device connected to the power supply path; as well as The determination unit, based on the measurement results obtained by the first acquisition unit and the operation information obtained by the second acquisition unit, determines whether an arc fault has occurred in the power supply path. The action information indicates the communication status with the device. If the determination unit determines that an electric arc has occurred based on the measurement results obtained by the first acquisition unit, and the communication state shown in the action information changes before and after the determination, the determination unit determines that no electric arc fault has occurred.

2. The arc detection system according to claim 1, wherein, The second acquisition unit also acquires driving information as the operation information, the driving information indicating whether the communication function between the device and the second acquisition unit is battery powered. When the communication function between the device and the second acquisition unit is driven by the battery, the determination unit determines whether an arc fault has occurred in the power supply path without referring to the communication status.

3. An arc detection system, wherein, have: The first acquisition unit acquires the measurement results of the current flowing in the power supply path from which power is supplied, or the voltage in the power supply path. The second acquisition unit acquires action information related to the operation of the device connected to the power supply path; as well as The determination unit, based on the measurement results obtained by the first acquisition unit and the operation information obtained by the second acquisition unit, determines whether an arc fault has occurred in the power supply path, wherein... If the determination unit determines that the time for which an electric arc has occurred is greater than or equal to a threshold time based on the measurement results obtained by the first acquisition unit, the determination unit determines that the electric arc fault has occurred without relying on the action information obtained by the second acquisition unit.

4. An arc detection method, wherein, include: The first obtaining step is to obtain the measurement results of the current flowing in the power supply path from which power is supplied, or the voltage in the power supply path. The second acquisition step involves acquiring action information related to the operation of the device connected to the power supply path; as well as The determination step, based on the measurement results obtained in the first acquisition step and the action information obtained in the second acquisition step, determines whether an arc fault has occurred in the power supply path. The action information indicates the communication status with the device. In the determination step, if it is determined that an electric arc has occurred based on the measurement results obtained from the first acquisition step, and the communication status shown by the action information changes before and after the determination, it is determined that no electric arc fault has occurred.

5. An arc detection method, wherein, include: The first obtaining step is to obtain the measurement results of the current flowing in the power supply path from which power is supplied, or the voltage in the power supply path. The second acquisition step involves acquiring action information related to the operation of the device connected to the power supply path; as well as The determination step, based on the measurement results obtained in the first acquisition step and the action information obtained in the second acquisition step, determines whether an arc fault has occurred in the power supply path. In the determination step, if it is determined that the time for which an electric arc was generated is greater than or equal to a threshold time based on the measurement result obtained in the first acquisition step, the electric arc fault is determined to have occurred without relying on the action information obtained in the second acquisition step.

6. A program recording medium for recording a program, wherein, The program causes one or more processors to execute the arc detection method according to claim 4 or 5.

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