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

Abstract

An arc detection system (100) includes a first acquisition unit (11), a second acquisition unit (12), and a determination unit (14). The first acquisition unit (11) acquires a measurement result of a current (I1) flowing through a power supply path (L1) from which power is supplied from a power supply (2) or a voltage (V1) in the power supply path (L1). The second acquisition unit (12) acquires variation information related to variation of a load (31) possessed by an apparatus (3) connected to the power supply path (L1). The determination unit (14) determines whether an arc fault occurs in the power supply path (L1) based on a component of a specific frequency band in the measurement result acquired by the first acquisition unit (11) and the variation 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 variation information related to variations in the load of a device connected to the power supply path. The determination unit determines whether an arc fault has occurred in the power supply path based on specific frequency band components in the measurement results acquired by the first acquisition unit and the variation information acquired by the second acquisition unit.

[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, variation information related to variations in the load of a device connected to the power supply path is acquired. In the determination step, based on a specific frequency band component in the measurement result acquired in the first acquisition step and the variation 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 the implementation method.

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

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

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

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

[0019] 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.

[0020] 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.

[0021] [structure]

[0022] use Figure 1 The arc detection system of the implementation method will be described. Figure 1 This is a schematic diagram showing the overall structure of the arc detection system 100 including the implementation method.

[0023] 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.

[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 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.

[0025] 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.

[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 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. If 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. Furthermore, in this embodiment, the power source 2 can be any type of power source that outputs DC power; it can 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 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 the embodiment, 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.

[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 while device 3 is in operation. That is, in this embodiment, 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.

[0029] 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.

[0030] 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.

[0031] In this embodiment, device 3 is a lighting fixture, but it can also be, for example, a speaker, a camera, a sensor, or a 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 this embodiment, 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.

[0032] The arc detection system 100 includes a first acquisition unit 11, a second acquisition unit 12, a third acquisition unit 13, a determination unit 14, a notification unit 15, and a stop unit 16, serving as functional components for determining whether an arc fault has occurred. In this embodiment, the first acquisition unit 11, the determination unit 14, the notification unit 15, and the stop unit 16 are provided in the power supply 2. Furthermore, the second acquisition unit 12 and the third acquisition unit 13 are provided in a communication module 20, which is connected separately to the power supply path L1. The communication module 20 is configured to communicate with the power supply 2 via, for example, wireless communication or power line communication (PLC).

[0033] 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, including ROM and RAM storing programs, a processor (CPU: Central Processing Unit) executing the programs, a timer, an A / D converter, and a D / A converter. The first acquisition unit 11, the second acquisition unit 12, the third acquisition unit 13, the determination unit 14, the notification unit 15, and the stop unit 16 are all implemented by the processor executing the aforementioned programs.

[0034] 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 this embodiment, 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.

[0035] The second acquisition unit 12 acquires change information related to changes in the load 31 of the device 3 connected to the power supply path L1. Here, a change in the load 31 refers to a change in the power consumed by the load 31, particularly a change in the current flowing through the load 31. Furthermore, the change information may include information that directly or indirectly indicates changes in the power consumed by the load 31 (or the current flowing through the load 31). Changes in the load 31 may occur, for example, when the power supply to the device 3 is switched on / off or when the operating mode of the device 3 is changed.

[0036] In this embodiment, the second acquisition unit 12 obtains the change in power consumed by the load 31 as change information by communicating with the device 3. That is, the device 3 periodically measures the power consumed by the load 31 (or the current flowing through the load 31) using, for example, an equipped ammeter. Then, the second acquisition unit 12 obtains the measurement results from the device 3 by communicating with it, calculates the change in power consumed by the load 31 based on the timing data of the obtained measurement results, and obtains it as change information. Alternatively, the change in power consumed by the load 31 can also be calculated by the device 3. In this case, the second acquisition unit 12 obtains the change in power consumed by the load 31 as change information by communicating with the device 3. 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.

[0037] The third acquisition unit 13 acquires status information related to the operating state of the device 3. Here, the operating state of the device 3 can generally include a normal state and a standby state. The normal state refers to the state where the load 31 of the device 3 receives power and operates, performing its normal functions. The standby state refers to the state where the load 31 of the device 3 receives power but does not perform its normal functions, awaiting a command to switch back to the normal state. In the standby state, compared to the normal state, the power consumed by the load 31 (or the current flowing through the load 31) is less.

[0038] In this embodiment, the third acquisition unit 13 communicates with the device 3, receives a signal containing status information from the device 3, and acquires the status information from the device 3. Alternatively, the third acquisition unit 13 may acquire the status information based on the communication volume with the device 3; if the communication volume is greater than a predetermined amount, it acquires the status information as a normal state; if the communication volume is less than a predetermined amount, it acquires the status information as a standby state. The communication standard between the third acquisition unit 13 and the device 3 is not particularly limited. Furthermore, the communication between the third acquisition unit 13 and the device 3 can be wired communication, wireless communication, or power line communication. In this embodiment, the second acquisition unit 12 and the third acquisition unit 13 may also be implemented by a single acquisition unit.

[0039] In this embodiment, both the second acquisition unit 12 and the third acquisition unit 13 communicate with the device 3, which operates connected to the power supply path L1, at a certain period (e.g., several hundred ms). For example, both the second acquisition unit 12 and the third acquisition unit 13 can communicate with the device 3 by receiving signals unilaterally transmitted from the device 3 operating connected to the power supply path L1. Alternatively, for example, both the second acquisition unit 12 and the third acquisition unit 13 can 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.

[0040] Furthermore, the signals transmitted from device 3 to the second acquisition unit 12 and the third acquisition unit 13 include identification information of the transmitting device 3. Therefore, the arc detection system 100 can grasp change information and status information for each device 3.

[0041] The determination unit 14 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 variation information obtained by the second acquisition unit 12. Specifically, the determination unit 14 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 14 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 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.

[0042] Then, the determination unit 14 determines whether an arc has occurred based not only on the measurement results obtained by the first acquisition unit 11, but also by referring to the change information obtained by the second acquisition unit 12 to determine whether an arc fault has occurred on the power supply path L1. That is, the determination unit 14 determines that an arc has occurred based solely on the measurement results obtained by the first acquisition unit 11, but 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.

[0043] In the DC distribution network 200, an electric arc may occur due to a break or partial break in the power supply path L1. When such an arc occurs, a specific frequency band component overlaps with the current I1 (or voltage V1). Therefore, the determination unit 14 may 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, a specific frequency band component may also overlap with the current I1 (or voltage V1). This phenomenon can occur not only in the DC distribution network 200 but also in the AC (Alternating Current) distribution network.

[0044] Here, the arc caused by a break or partial break in the power supply path L1 is often considered the cause of arc faults. However, the aforementioned phenomenon is not caused by an arc in the power supply path L1 and therefore does not constitute a cause of arc faults. Therefore, in the arc detection system 100, it is desirable not to detect the aforementioned phenomenon, but rather to primarily determine the generation of an arc caused by a break or partial break in the power supply path L1 as the occurrence of an arc fault.

[0045] Therefore, in this embodiment, to meet the above requirements, the determination unit 14 determines whether an arc fault has occurred in the power supply path L1 as follows: First, the determination unit 14 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 14 monitors the duration of the arc. If the duration is less than a first threshold, the determination unit 14 determines that no arc fault has occurred in the power supply path L1, regardless of the change information obtained by the second acquisition unit 12. Furthermore, if the duration is above the first threshold and below the second threshold, the determination unit 14 determines whether an arc fault has occurred in the power supply path L1, as in the first or second determination example shown below. Additionally, if the duration is above the second threshold, the determination unit 14 determines whether an arc fault has occurred in the power supply path L1, as in the third determination example shown below. The first and second thresholds are, for example, preset by the user of the arc detection system 100.

[0046] Figure 2A This is a timing diagram showing the first determination example of the determination unit 14 of the arc detection system 100 according to the embodiment. Figure 2B This is a timing diagram showing a second determination example of the determination unit 14 of the arc detection system 100 according to an embodiment. Figure 2C This is a timing diagram showing a third determination example of the determination unit 14 of the arc detection system 100 according to an embodiment. 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 14 determines that an electric arc has occurred. Furthermore, in... Figures 2A to 2CIn the various diagrams, the pulses in the timing diagram below indicate sharp changes in load 31. Additionally, in... Figure 2B As will be described later, since no abrupt changes occur in load 31, there is no illustrated pulse.

[0047] like Figure 2A As shown, in the first determination example, the determination unit 14 determines the time point (hereinafter also referred to as the "determination time point") t1 where an arc occurred based on the measurement results obtained by the first acquisition unit 11, and the second acquisition unit 12 obtains change information indicating that a sharp change occurred in the load 31. Therefore, in the first determination example, since a sharp change occurred in the load 31 at the determination time point t1, the determination unit 14 determines that no arc occurred in the power supply path L1, and that no arc fault occurred in the power supply path L1.

[0048] like Figure 2B As shown, in the second determination example, at determination time t1, the second acquisition unit 12 acquires change information indicating that no change has occurred in the load 31. Therefore, in the second determination example, since no drastic change has occurred in the load 31 at determination time t1, the determination unit 14 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.

[0049] Thus, in both the first and second determination examples, if an arc is determined to have occurred based on the measurement results obtained by the first acquisition unit 11, and a sharp change occurs in the load 31 at the time of this determination, then the determination unit 14 determines that no arc fault has occurred. Here, whether a sharp change occurs in the load 31 is determined based on the amount of change (gradient) in the power consumed by the load 31 per unit time, i.e., whether the amount of change in the power consumed by the load 31 is above a threshold. Specifically, if the amount of change is above the threshold, the determination unit 14 determines that a sharp change has occurred in the load 31; if the amount of change is less than the threshold, the determination unit 14 determines that no sharp change has occurred in the load 31. The threshold is, for example, preset by the user of the arc detection system 100.

[0050] Furthermore, "determination time" includes not only the instant of determination time point t1, but also the range from a time point earlier than determination time point t1 to a time point later than determination time point t1.

[0051] like Figure 2CAs shown, in the third determination example, the second acquisition unit 12 acquires change information indicating a sharp change in the load 31, but the determination unit 14 determines that the duration of the arc is longer than the second threshold (threshold time Th1). Therefore, in the third determination example, the determination unit 14 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 change information acquired by the second acquisition unit 12. Thus, when the determination unit 14 determines that the time of arc occurrence is greater than or equal to the second threshold (threshold time Th1) based on the measurement results acquired by the first acquisition unit 11, it determines that an arc fault has occurred without relying on the change information acquired by the second acquisition unit 12.

[0052] Furthermore, in this embodiment, the determination unit 14 determines whether an arc fault has occurred in the power supply path L1 by referring to the status information obtained by the third acquisition unit 13. Specifically, if it is determined that an arc has occurred based on the measurement results obtained by the first acquisition unit 11, and the operating state of the device 3 obtained by the third acquisition unit 13 is in standby mode, then the determination unit 14 determines that an arc fault has occurred without relying on the change information obtained by the second acquisition unit 12. That is, if the operating state of the device 3 is in standby mode, since the power originally consumed by the load 31 is relatively small, there will be no drastic changes in the load 31. Therefore, if the operating state of the device 3 is in standby mode, the determination unit 14 determines that an arc fault has occurred based on the measurement results obtained by the first acquisition unit 11 without referring to the change information.

[0053] The notification unit 15 can notify the surrounding area of ​​an arc fault, for example, by turning on a light or sounding a buzzer. Alternatively, the notification unit 15 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.

[0054] If the determination unit 14 determines that an arc fault has occurred, the stopping unit 16 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.

[0055] For example, the stop unit 16 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.

[0056] 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 constituting a switch connected to the power supply path L1. For example, the stop unit 16 stops the switching operation of the switch by controlling it, thereby stopping the current flowing in the power supply path L1.

[0057] Alternatively, the switch can be configured to toggle the connection and disconnection of the power supply 2. In this case, the stop unit 16 controls the switch to disconnect the power supply 2, thereby stopping the current flowing in the power supply path L1.

[0058] 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 16 can also open the power supply path L1 by controlling the switch, thereby stopping the current flowing in the power supply path L1.

[0059] [action]

[0060] The following uses Figure 3 An example of the operation of the arc detection system 100 according to the embodiment will be described. Figure 3 This is a flowchart illustrating an example of the operation of the arc detection system 100 according to an implementation method.

[0061] 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 change information from each device 3 by communicating with each device 3 (S2). Processing S2 corresponds to the second acquisition step ST2 of the arc detection method. In addition, the third acquisition unit 13 acquires status information from each device 3 by communicating with each device 3 (S3).

[0062] Then, the determination unit 14 first determines whether an arc has occurred based on the components of a specific frequency band in the measurement result of the current I1 obtained by the first acquisition unit 11 (S4). Here, the determination unit 14 determines this by performing frequency analysis on the measurement result of the current I1 obtained by the first acquisition unit 11. If the determination unit 14 determines that an arc has occurred (S4: Yes), it monitors the duration of the determination that an arc has occurred (S5). On the other hand, if the determination unit 14 determines that no arc has occurred (S4: No), it determines that there is no arc fault (S9).

[0063] If an arc is detected, and the duration is less than a first threshold (S5: Yes), the determination unit 14 determines that no arc fault has occurred (S9). Conversely, if the duration is greater than or equal to a second threshold (S5: No, S6: No), the determination unit 14 determines that an arc fault has occurred (S10). On the other hand, if the duration is greater than or equal to the first threshold (S5: No) and less than the second threshold (S6: Yes), the determination unit 14 monitors the operating status of each device 3 by referring to the status information obtained by the third acquisition unit 13 (S7).

[0064] If any device 3 is in standby mode (S7: Yes), the determination unit 14 determines that an arc fault has occurred (S10). On the other hand, if at least one device 3 is in normal mode (S7: No), the determination unit 14 monitors whether a sharp change has occurred in the load 31 at the determination time t1, referring to the change information obtained by the second acquisition unit 12 (S8).

[0065] If a sudden change occurs in the load 31 in any device 3 operating normally (S8: Yes), the determination unit 14 determines that no arc fault has occurred (S9). On the other hand, if no sudden change occurs in the load 31 in any device 3 operating normally (S8: No), the determination unit 14 determines that an arc fault has occurred (S10). Processing S4 to S10 corresponds to the determination step ST3 of the arc detection method.

[0066] If the determination unit 14 determines that an arc fault has occurred (S10), the stop unit 16 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 (S11). Then, the notification unit 15 notifies that an arc fault has occurred (S12). On the other hand, if the determination unit 14 determines that no arc fault has occurred (S9), the processing of the arc detection system 100 ends. Hereinafter, the above series of processes S1 to S12 are repeated.

[0067] [advantage]

[0068] Hereinafter, the advantages of the arc detection system 100 of the embodiment 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 the embodiment in that it does not have a second acquisition unit 12 and a third acquisition unit 13. That is, in the arc detection system of the comparative example, the difference from the arc detection system 100 of the embodiment 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.

[0069] 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.

[0070] The comparative arc detection system can also detect the occurrence of arc faults. However, in the comparative arc detection system, an arc fault is detected not only when an arc is generated due to a break or partial break in the power supply path L1, but also when the load 31 of the machine 3 experiences a sudden change. That is, the comparative arc detection system incorrectly detects an arc fault even when no arc is actually generated. Thus, in the comparative arc detection system, every sudden change in the load 31 is detected as an arc fault, which may reduce the user's convenience. For example, since a notification of an arc fault may be generated every time the power supply to the device 3 is turned on / off, it is inconvenient for the user. In addition, for example, suppose the configuration automatically stops the power supply from the 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 the power supply to the device 3 is turned on / off, it is also inconvenient for the user.

[0071] On the other hand, in the arc detection system 100 of the embodiment, since the second acquisition unit 12 is provided, the determination unit 14 can determine whether a sudden change has occurred in the load 31. Therefore, in the arc detection system 100 of the embodiment, an arc fault is determined to have occurred when an arc is generated due to a break or partial break in the power supply path L1, and an arc fault is not generally determined to have occurred when there is a sudden change in the load 31.

[0072] That is, in the arc detection system 100 of the embodiment, the possibility of determining that an arc fault has occurred when a sudden change occurs in the load 31 is low. In other words, the arc detection system 100 of the embodiment has the advantage of easily preventing sudden changes in the load 31 from being mistakenly detected as an arc fault, and easily preventing false detection of arc faults. Therefore, the arc detection system 100 of the embodiment is less likely to produce the phenomenon that may occur in the arc detection system of the comparative example. That is, the arc detection system 100 of the embodiment can notify the user or stop the power supply to the power supply path L1 only when an arc fault occurs that is considered to have a particularly large impact on the user, thus having the advantage of good user convenience.

[0073] (Modified Example)

[0074] The embodiments have been described above, but the present invention is not limited to the embodiments described above. Hereinafter, variations of the embodiments are listed. The variations described below can also be appropriately combined.

[0075] In one implementation, the ammeter 22 is a separate device from the arc detection system 100, but it can be built into the arc detection system 100.

[0076] In this embodiment, the second acquisition unit 12 communicates with the device 3, which operates via the power supply path L1, at a fixed period, but is not limited to this. For example, the second acquisition unit 12 may communicate with the device 3 intermittently.

[0077] In this embodiment, the second acquisition unit 12 acquires change information by communicating with the device 3, but is not limited to this. For example, the second acquisition unit 12 may also acquire control commands sent to the device 3 as change information. This method can be implemented when the second acquisition unit 12 is able to acquire control commands sent to the device 3 by a controller that remotely controls the device 3. That is, when the device 3 receives the control command, it operates according to the content of the control command, and the load 31 changes. Therefore, the second acquisition unit 12 can indirectly grasp the change of the load 31 based on the content of the acquired control command.

[0078] Therefore, in this embodiment, if it is determined that an arc has occurred based on the measurement results obtained by the first acquisition unit 11, and the control command at the time of this determination is an instruction that causes the change in power consumption of the load 31 to be above a threshold, then the determination unit 14 determines that no arc fault has occurred. For example, if the content of the control command obtained by the second acquisition unit 12 is to turn the power supply of the device 3 on / off, or to change the operating mode of the device 3, the determination unit 14 presumes that a sharp change has occurred in the load 31. In this manner, it is possible to determine whether an arc fault has occurred without waiting for a signal from the device 3.

[0079] Furthermore, the second acquisition unit 12 can also acquire change information without communicating with the device 3. Here, when a sharp change occurs in the load 31 of the device 3, the current I1 flowing in the power supply path L1 also changes with this sharp change. Therefore, the second acquisition unit 12 can acquire change information based on, for example, the measurement result of the current I1 measured by the ammeter 22.

[0080] In this embodiment, the arc detection system 100 is provided at the power supply 2, but 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 unit 14.

[0081] In one embodiment, the determination unit 14 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, but is not limited thereto. For example, the determination unit 14 may also extract the 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.

[0082] In this embodiment, 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.

[0083] Furthermore, in this case, the determination unit 14 determines 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 unit 14 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 14 determines 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.

[0084] In one embodiment, the second acquisition unit 12 is provided in the communication module 20, which is connected to the power supply path L1 separately from the power supply 2, but is not limited thereto. For example, the second acquisition unit 12 may be provided in the power supply 2. In this case, the communication module 20 is not required in the arc detection system 100.

[0085] In one embodiment, the arc detection system 100 includes a third acquisition unit 13, but it may also omit the third acquisition unit 13. In this case, the determination unit 14 determines whether an arc fault has occurred based solely on the measurement results obtained by the first acquisition unit 11 and the change information obtained by the second acquisition unit 12.

[0086] In this embodiment, if it is determined that the duration of the arc is greater than or equal to a second threshold (threshold time Th1), the determination unit 14 determines that an arc fault has occurred without relying on the variation information obtained by the second acquisition unit 12, but is not limited thereto. For example, the determination unit 14 may also determine that an arc fault has occurred without relying on the variation information obtained by the second acquisition unit 12 if the components of a specific frequency band included in the measurement result contain a second predetermined value (> a first predetermined value).

[0087] In one embodiment, when the determination unit 14 determines that an arc fault has occurred, the stopping unit 16 stops the current flowing in the power supply path L1, but is not limited to this. For example, the stopping unit 16 may also be configured to disconnect the power supply to the device 3 separately when the determination unit 14 determines that an arc fault has occurred. This method can be implemented, for example, by having the device 3 equipped with a DC / DC converter circuit, and the stopping unit 16 sending a command to the device 3 to disconnect the switching element of the DC / DC converter circuit. In this method, it is possible to disconnect the power supply to only the device 3 related to the arc fault, while maintaining the operation of other devices 3.

[0088] In this implementation, 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.

[0089] 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.

[0090] 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, variation information related to variations in the load 31 of the device 3 connected to the power supply path L1 is acquired. In the determination step ST3, based on the specific frequency band components in the measurement results acquired in the first acquisition step ST1 and the variation information acquired in the second acquisition step ST2, it is determined whether an arc fault has occurred in the power supply path L1.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] (Summarize)

[0095] As described above, the arc detection system 100 includes a first acquisition unit 11, a second acquisition unit 12, and a determination unit 14. The first acquisition unit 11 acquires 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. The second acquisition unit 12 acquires change information related to changes in the load 31 of the device 3 connected to the power supply path L1. The determination unit 14 determines 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 change information acquired by the second acquisition unit 12.

[0096] According to such an arc detection system 100, it has the advantage of easily preventing abrupt changes in load 31 from being mistakenly detected as an arc fault, and easily preventing false detections of arc faults.

[0097] Additionally, for example, in the arc detection system 100, the second acquisition unit 12 communicates with the device 3 to obtain the change in the amount of power consumed by the load 31 as change information. If it is determined that an arc has occurred based on the measurement results obtained by the first acquisition unit 11, and the change obtained by the second acquisition unit 12 is above a threshold at the time of determination, then the determination unit 14 determines that no arc fault has occurred.

[0098] According to such an arc detection system 100, by referring to the change in the amount of power consumed by the load 31, it is easy to detect abrupt changes in the load 31, thus having the advantage of easily preventing false detections of arc faults.

[0099] Additionally, for example, in the arc detection system 100, the second acquisition unit 12 acquires the control command sent to the device 3 as change information. If, based on the measurement results acquired by the first acquisition unit 11, it is determined that an arc has occurred, and at the time of this determination, the control command is an instruction whose change in the power consumed by the load 31 is above a threshold, then the determination unit 14 determines that no arc fault has occurred.

[0100] According to such an arc detection system 100, even without obtaining the amount of change in the power consumed by the load 31 from the device 3, it is possible to detect abrupt changes in the load 31, thus having the advantage of easily reducing the amount of communication.

[0101] In addition, for example, in the arc detection system 100, if the determination unit 14 determines 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, it determines that an arc fault has occurred without relying on the change information obtained by the second acquisition unit 12.

[0102] According to such an arc detection system 100, compared with the case of reference change information, it has the advantage of being able to easily determine that an arc fault has occurred at an early stage.

[0103] Additionally, for example, the arc detection system 100 also includes a third acquisition unit 13 for acquiring status information related to the operating state of the device 3. If an arc is determined to have occurred based on the measurement results acquired by the first acquisition unit 11, and the operating state of the device 3 acquired by the third acquisition unit 13 is a standby state, then the determination unit 14 determines that an arc fault has occurred without relying on the change information acquired by the second acquisition unit 12.

[0104] According to such an arc detection system 100, compared with the case of reference change information, it has the advantage of being able to easily determine that an arc fault has occurred at an early stage.

[0105] 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, variation information related to variations in the load 31 of the device 3 connected to the power supply path L1 is acquired. In the determination step ST3, based on the specific frequency band components in the measurement results acquired in the first acquisition step ST1 and the variation information acquired in the second acquisition step ST2, it is determined whether an arc fault has occurred in the power supply path L1.

[0106] According to this arc detection method, it has the advantages of easily preventing abrupt changes in load 31 from being mistakenly detected as an arc fault, and easily preventing false detections of arc faults.

[0107] Alternatively, for example, a program recording medium records a program that causes one or more processors to execute the above-described arc detection method.

[0108] The recording medium according to such a procedure has the advantage of easily preventing abrupt changes in load 31 from being mistakenly detected as an arc fault, and easily preventing false detection of arc faults.

[0109] Explanation of reference numerals in the attached figures

[0110] 11 First Acquisition Department

[0111] 12 Second Acquisition Department

[0112] 13 Third Acquisition Department

[0113] 14 Judgment Department

[0114] 2 power supplies

[0115] 3 devices

[0116] 31 load

[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] 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 change information related to changes in the load of the device connected to the power supply path; as well as The determination unit, based on the components of a specific frequency band in the measurement results obtained by the first acquisition unit and the variation information obtained by the second acquisition unit, determines whether an arc fault has occurred in the power supply path. The second acquisition unit acquires the control command sent to the device as the change information. If, based on the measurement results obtained by the first acquisition unit, it is determined that an electric arc has occurred, and at the time of this determination, the control command is an instruction that causes the change in the power consumed by the load to be above a threshold, then the determination unit determines that the electric arc fault has not occurred.

2. The arc detection system according to claim 1, wherein, If, based on the measurement results obtained by the first acquisition unit, it is determined that the time during which an electric arc occurred is greater than or equal to a threshold time, the determination unit determines that the electric arc fault has occurred without relying on the change information obtained by the second acquisition unit.

3. The arc detection system according to claim 1, wherein, It also includes a third acquisition unit that acquires state information related to the operating state of the device. If an arc is determined to have occurred based on the measurement result obtained by the first acquisition unit, and the operating state of the device obtained by the third acquisition unit is a standby state, then the determination unit determines that the arc fault has occurred without relying on the change 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 change information related to changes in the load of the device connected to the power supply path; as well as The determination step, based on the specific frequency band components in the measurement results obtained in the first acquisition step and the variation information obtained in the second acquisition step, determines whether an arc fault has occurred in the power supply path. In the second acquisition step, the control command sent to the device is acquired as the change information. In the determination step, if it is determined that an electric arc has occurred based on the measurement result obtained from the first acquisition step, and the control command at the time of determination is a command that causes the change in the power consumed by the load to be above a threshold, then it is determined that the electric arc fault has not occurred.

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

Images