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EP-4120494-B1 - ARC DETECTION DEVICE, POWER CONDITIONER, INDOOR WIRING SYSTEM, BREAKER, SOLAR PANEL, SOLAR PANEL-ATTACHED MODULE, AND CONNECTION BOX

EP4120494B1EP 4120494 B1EP4120494 B1EP 4120494B1EP-4120494-B1

Inventors

  • OHSHIMA, KAZUYA
  • KOGA, TATSUO
  • KANAMORI, Keita
  • KIDERA, KAZUNORI

Dates

Publication Date
20260506
Application Date
20210303

Claims (7)

  1. An arc detection device comprising: a current detector that includes a magnetic core (21) penetrated by a first path and a second path each connecting a direct current (DC) power source (40) and a device, and detects a current flowing through each of the first path and the second path in accordance with a magnetic field generated at the magnetic core (21); a low impedance circuit having a lower impedance than impedances of the DC power source (40) and the device, the low impedance circuit being connected to the first path and the second path to cause a high frequency component to bypass one of the first path or the second path; and an arc determiner (30) that determines an occurrence of an arc based on the current detected by the current detector, wherein in the magnetic core (21), a direct current flows through the first path in a direction opposite to a direction in which a direct current flows through the second path, wherein the arc detection device is characterized in that the DC power source (40) feeds electric power to the device via a first wire and a second wire, the first wire being connected to one of a positive electrode and a negative electrode of the DC power source (40), the second wire being connected to another one of the positive electrode and the negative electrode of the DC power source (40), and the first path and the second path pass through the first wire, the first wire penetrates the magnetic core (21) from one side to another side of the magnetic core (21) and then turns around in the first path, and penetrates the magnetic core (21) from the another side to the one side of the magnetic core (21) in the second path, wherein the low impedance circuit is placed in a bypass path connecting a connection point in the turnaround and a connection point on the first wire between the one side of the magnetic core (21) and the device, or wherein the low impedance circuit is placed in a bypass path connecting a connection point in the turnaround and a connection point on the first wire between the one side of the magnetic core (21) and one of the positive electrode and the negative electrode of the DC power source (40), or wherein the low impedance circuit is placed in a bypass path connecting a connection point in the turnaround and a connection point on the second wire.
  2. A solar inverter comprising: the arc detection device according to claim 1; and a converter that converts electric power output from the DC power source (40).
  3. An indoor wiring system comprising: the arc detection device according to claim 1; the first path (51a); the second path (52a); and the device placed indoors.
  4. A breaker comprising the arc detection device according to claim 1, wherein the breaker blocks a current flowing through each of the first wire and the second wire, when an occurrence of an arc is determined.
  5. A solar panel comprising the arc detection device according to claim 1, wherein the solar panel generates electricity from sunlight.
  6. A solar panel-attached module comprising the arc detection device according to claim 1, wherein the solar panel-attached module converts a signal output from a solar panel.
  7. A junction box comprising the arc detection device according to claim 1, wherein the junction box connects a solar panel and a solar inverter.

Description

[Technical Field] The present invention relates to an arc detection device, a solar inverter, an indoor wiring system, a breaker, a solar panel, a solar panel-attached module, and a junction box. [Background Art] Typically known is a system that convers direct current (DC) power fed from a photovoltaic (PV) panel (i.e., a solar panel) via a wire into alternating current (AC) power, using a device such as an inverter. There are reports that such a wire is damaged or broken by external factors, aging, or other reasons. Such a damage or any other problem of the wire may cause an arc (i.e., an arc discharge). Arc detection means for detecting an arc are suggested (e.g., JP2011-7765 A). JP 2017-161240 A discloses an arc detection device, in which positive and negative output lines of a solar cell string are connected to a bypass current path including a capacitor. JP 2012-145363 A discloses a failure detection and protection circuit of a DC power supply system. The failure detection and protection circuit of the DC power supply system is a leakage detection circuit which includes two power supply disconnection parts two one-way conduction devices a leakage current detector and a voltage temporary compensator. Systems for arc detection using current sensing are also disclosed in the following prior art documents: JP 2020 139925 A, JP 2017 161240 A, US 2011/141644 A1 and GB 2 457 766 A. [Summary of Invention] [Technical Problem] There is a method of detecting a magnetic field generated at a current sensor using a current flowing through a wire and detecting an arc based on the current corresponding to the magnetic field. This method may cause however magnetic saturation in a magnetic core of the current sensor and thus fail to detect an arc accurately. To address the problem, it is an objective of the present invention to provide an arc detection device, for example, capable of detecting an arc accurately. [Solution to Problem] An arc detection device according to an aspect of the present invention as defined in the appended claim 1 includes: a current detector that includes a magnetic core penetrated by a first path and a second path each connecting a direct current (DC) power source and a device, and detects a current flowing through each of the first path and the second path in accordance with a magnetic field generated at the magnetic core; a low impedance circuit having a lower impedance than impedances of the DC power source and the device, the low impedance circuit being connected to the first path and the second path to cause a high frequency component to bypass one of the first path or the second path; and an arc determiner that determines an occurrence of an arc based on the current detected by the current detector. In the magnetic core, a direct current flows through the first path in a direction opposite to a direction in which a direct current flows through the second path, wherein the arc detection device is characterized in that the DC power source feeds electric power to the device via a first wire and a second wire, the first wire being connected to one of a positive electrode and a negative electrode of the DC power source, the second wire being connected to another one of the positive electrode and the negative electrode of the DC power source, and the first path and the second path pass through the first wire,the first wire penetrates the magnetic core from one side to another side of the magnetic core and then turns around in the first path, and penetrates the magnetic core from the another side to the one side of the magnetic core in the second path,wherein the low impedance circuit is placed in a bypass path connecting a connection point in the turnaround and a connection point on the first wire between the one side of the magnetic core and the device, or wherein the low impedance circuit is placed in a bypass path connecting a connection point in the turnaround and a connection point on the first wire between the one side of the magnetic core and one of the positive electrode and the negative electrode of the DC power source, or wherein the low impedance circuit is placed in a bypass path connecting a connection point in the turnaround and a connection point on the second wire. A solar inverter according to an aspect of the present invention includes: the arc detection device described above; and a converter that converts electric power output from the DC power source. An indoor wiring system according to an aspect of the present invention includes: the arc detection device described above; the first path; the second path; and the device placed indoors. A breaker according to an aspect of the present invention includes the arc detection device described above. The breaker blocks a current flowing through each of the first wire and the second wire, when an occurrence of an arc is determined. A solar panel according to an aspect of the present invention includes the arc detection device descr