US-12627133-B2 - Arc detection device, breaker, power conditioner, solar panel, solar-panel-attached module, junction box, arc detection system, and arc detection method

Abstract

An arc detection device that detects an arc fault that occurs in a transmission line connecting a DC power supply that generates DC power and a power converter that converts the DC power to AC power, includes: a first determination unit that determines whether or not there is a possibility of an arc fault occurrence according to current flowing in the transmission line; a shutoff unit that temporarily stops the flow of current in the transmission line when the first determination unit determines there is a possibility of an arc fault occurrence; and a second determination unit that determines whether or not an arc fault has occurred according to an input voltage, of the power converter supplied from the DC power supply, after lifting temporary stoppage of the flow of current in the transmission line.

Inventors

• Tatsuo Koga
• Keita KANAMORI
• Kazunori Kidera
• Yoshio Mitsutake

Assignees

• PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.

Dates

Publication Date

20260512

Application Date

20210205

Claims (11)

1. 1 . An arc detection device that detects an arc fault that occurs in a transmission line connecting a DC power supply that generates DC power and a power converter that converts the DC power to AC power, the arc detection device comprising: a first determination unit configured to determine whether or not there is a possibility of an arc fault occurrence according to current flowing in the transmission line; a shutoff unit configured to temporarily stop flow of current in the transmission line when the first determination unit determines there is a possibility of an arc fault occurrence; and a second determination unit configured to determine whether or not an arc fault has occurred according to an input voltage, of the power converter supplied from the DC power supply, after lifting temporary stoppage of the flow of current in the transmission line, wherein the first determination unit is configured to perform a frequency analysis of current flowing in the transmission line and determine there is a possibility of an arc fault occurrence when the current includes a component in a specific frequency band, and the second determination unit is configured to determine that an arc fault has occurred when the input voltage after lifting temporary stoppage of the flow of current in the transmission line is less than a predetermined value.
2. 2 . The arc detection device according to claim 1 , wherein the shutoff unit is configured to temporarily stop the flow of current in the transmission line by controlling a switch connected to the transmission line.
3. 3 . The arc detection device according to claim 2 , wherein the switch is a mechanical switch or a semiconductor switch.
4. 4 . The arc detection device according to claim 1 , further comprising: a notification unit configured to notify of an arc fault occurrence when the second determination unit determines that an arc fault has occurred.
5. 5 . A breaker comprising: the arc detection device according to claim 1 , wherein the breaker interrupts the flow of current in the transmission line when the arc detection device detects that an arc fault has occurred.
6. 6 . A power conditioner comprising: the arc detection device according to claim 1 ; and the power converter.
7. 7 . A solar panel comprising: the arc detection device according to claim 1 , wherein the solar panel is the DC power supply.
8. 8 . 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 which is the DC power supply.
9. 9 . A junction box comprising: the arc detection device according to claim 1 , wherein the junction box connects a solar panel which is the DC power supply and a power conditioner including the power converter.
10. 10 . An arc detection system comprising: the arc detection device according to claim 1 ; the DC power supply; and the power converter.
11. 11 . An arc detection method of detecting an arc fault that occurs in a transmission line connecting a DC power supply that generates DC power and a power converter that converts the DC power to AC power, the arc detection method comprising: determining whether or not there is a possibility of an arc fault occurrence according to current flowing in the transmission line; temporarily stopping flow of current in the transmission line when it is determined there is a possibility of an arc fault occurrence; and determining whether or not an arc fault has occurred according to an input voltage, of the power converter supplied from the DC power supply, after lifting temporary stoppage of the flow of current in the transmission line, wherein the determining of whether or not there is a possibility of an arc fault occurrence includes performing a frequency analysis of current flowing in the transmission line and determining there is a possibility of an arc fault occurrence when the current includes a component in a specific frequency band, and the determining of whether or not an arc fault has occurred includes determining that an arc fault has occurred when the input voltage after lifting temporary stoppage of the flow of current in the transmission line is less than a predetermined value.

Description

TECHNICAL FIELD The present invention relates to an arc detection device and the like for detecting arc faults that occur in a transmission line connecting a DC power supply and a power converter. BACKGROUND ART A conventional system is known which converts DC power supplied from a DC power supply such as a photo voltaic (PV) panel (i.e., a solar panel) via a transmission line to AC power using a power conditioner. There have been reports of transmission lines connecting PV panels and power conditioners being damaged or ruptured by external factors or age-related deterioration. Arc faults may occur due to such transmission line damage. In view of this, arc detection means for detecting arc faults have been proposed (for example, see PTL 1). The arc detection means disclosed in PTL 1 attempts to detect arc faults based on fluctuations in the current and voltage applied to the transmission line. CITATION LIST Patent Literature [PTL 1] Japanese Unexamined Patent Application Publication No. 2011-7765 SUMMARY OF INVENTION Technical Problem However, the techniques disclosed in PTL 1 may incorrectly detect that an arc fault has occurred even though no arc fault has actually occurred when fluctuation in the current and voltage applied to the transmission line is not due to an arc fault but to disturbance noise, for example. In view of this, the present invention has an object to provide an arc detection device and the like that can accurately detect arc faults that occur in a transmission line. Solution to Problem In order to achieve the above object, in one aspect, an arc detection device according to the present invention detects an arc fault that occurs in a transmission line connecting a DC power supply that generates DC power and a power converter that converts the DC power to AC power, and includes: a first determination unit configured to determine whether or not there is a possibility of an arc fault occurrence according to current flowing in the transmission line; a shutoff unit configured to temporarily stop flow of current in the transmission line when the first determination unit determines there is a possibility of an arc fault occurrence; and a second determination unit configured to determine whether or not an arc fault has occurred according to an input voltage, of the power converter supplied from the DC power supply, after lifting temporary stoppage of the flow of current in the transmission line. In order to achieve the above object, in one aspect, a breaker according to the present invention includes the arc detection device described above, and interrupts the flow of current in the transmission line when the arc detection device detects that an arc fault has occurred. In order to achieve the above object, in one aspect, a power conditioner according to the present invention includes the arc detection device and the power converter described above. In order to achieve the above object, in one aspect, a solar panel according to the present invention is the DC power supply described above and includes the arc detection device described above. In order to achieve the above object, in one aspect, a solar-panel-attached module according to the present invention includes the arc detection device described above, and converts a signal output from a solar panel, which is the DC power supply described above. In order to achieve the above object, in one aspect, a junction box according to the present invention includes the arc detection device described above, and connects a solar panel, which is the DC power supply described above, and a power conditioner including the power converter described above. In order to achieve the above object, in one aspect, an arc detection system according to the present invention includes the arc detection device, the DC power supply, and the power converter described above. In order to achieve the above object, in one aspect, an arc detection method according to the present invention is a method of detecting an arc fault that occurs in a transmission line connecting a DC power supply that generates DC power and a power converter that converts the DC power to AC power, includes: determining whether or not there is a possibility of an arc fault occurrence according to current flowing in the transmission line; temporarily stopping flow of current in the transmission line when it is determined there is a possibility of an arc fault occurrence; and determining whether or not an arc fault has occurred according to an input voltage, of the power converter supplied from the DC power supply, after lifting temporary stoppage of the flow of current in the transmission line. Advantageous Effects of Invention According to one aspect of the present invention, an arc fault that occurs in a transmission line can be accurately detected. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating one example of an arc detection system to which an arc detection device of Embodiment 1 has