Arc detector and arc detection method

Patent metadata

Field	Value
Publication number	US-10554035-B2
Application number	US-201715657306-A
Country	US
Kind code	B2
Filing date	Jul 24, 2017
Priority date	Feb 18, 2015
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

An arc detector includes a current sensor, a power spectrum conversion unit that converts an output from the current sensor to a power spectrum, a section value obtaining unit that divides an arc measurement section for the power spectrum into a plurality of regions, and obtains, from region values for the plurality of regions excluding a maximum one of the region values, a region value to be a section value of the arc measurement section, and an arc determination unit that determines a presence of an arc by comparing the section value with a threshold.

First claim

The invention claimed is:

1. An arc detector, comprising:
a current sensor configured to detect an output current from a distributed direct-current power supply; and
a processor configured to perform operations comprising:
operation as a power spectrum conversion unit configured to convert the output current from the current sensor to a power spectrum;
operation as a section value obtaining unit configured to
divide an arc measurement section for the power spectrum having a predetermined frequency range-into a plurality of regions, and
obtain, from region values determined for the plurality of regions, each of the region values indicating a magnitude of the power spectrum for a respective region of the plurality of regions, and with a maximum one of the region values being excluded, a region value to be a section value of the arc measurement section; and

operation as an arc determination unit configured to determine a presence of an arc by comparing the magnitude of the power spectrum for the section value with a predetermined threshold.

2. The arc detector according to claim 1 , wherein the processor is configured to perform operations such that operation as the section value obtaining unit comprises operation as the section value obtaining unit that obtains, as the section value, a minimum one of the region values determined for the plurality of regions.

3. The arc detector according to claim 1 , wherein
the arc measurement section has a frequency range greater than 2 kHz, and
the processor is configured to perform operations such that operation as the section value obtaining unit comprises operation as the section value obtaining unit that obtains the region value to be selected as the section value from a portion of the arc measurement section that excludes a frequency range of 2 kHz the frequency range comprising a frequency corresponding to a maximum value of the power spectrum.

4. The arc detector according to claim 1 , wherein the processor is configured to perform operations such that:
operation as the section value obtaining unit comprises operation as the section value obtaining unit that obtains a plurality of the section values for a plurality of the arc measurement sections, and
operation as the arc determination unit comprises operation as the arc determination unit that determines the presence of the arc by comparing a value calculated using the plurality of the section values with the predetermined threshold.

5. The arc detector according to claim 1 , wherein the processor is configured to perform operations such that:
operation as the section value obtaining unit comprises operation as the section value obtaining unit that obtains a plurality of the section values for a plurality of the arc measurement sections, and
operation as the arc determination unit comprises operation as the arc determination unit that determines the presence of the arc by comparing a selected one of the plurality of the section values with the predetermined threshold.

6. The arc detector according to claim 1 , wherein the processor is configured to perform operations such that operation as the power spectrum conversion unit comprises operation as the power spectrum conversion unit that converts the output current from the current sensor to the power spectrum for the arc measurement section.

7. An arc detector, comprising:
a current sensor configured to detect an output current from a distributed direct-current power supply; and
a processor configured to perform operations comprising:
operation as a power spectrum conversion unit configured to convert the output current from the current sensor to a power spectrum;
operation as a section value obtaining unit configured to:
divide an arc measurement section for the power spectrum having a predetermined frequency range into a plurality of regions,
obtain, from region values determined for the plurality of regions each of the region values indicating a magnitude of the power spectrum for a respective region of the plurality of regions, and with a maximum one of the region values being excluded, a region value to be a section value of the arc measurement section, and
obtain a section value of a noise measurement section for the power spectrum having a frequency range different from the frequency range of the arc measurement section; and

operation as an arc determination unit configured to determine a presence of an on by comparing a value calculated from the section value of the arc measurement section and the section value of the noise measurement section with a predetermined threshold.

8. The arc detector according to claim 7 , wherein the processor is configured to perform operations such that:
operation as the arc determination unit comprises operation as the arc determination unit that determines the presence of the arc by comparing, as the value calculated from the section value of the arc measurement section and the section value of the noise measurement section, at least one of a ratio of the section value of the arc measurement section to the section value of the noise measurement section, and a difference between the section value of the arc measurement section and the section value of the noise measurement section, with the predetermined threshold.

9. The arc detector according to claim 7 , wherein the processor is configured to perform operations such that:
operation as the section value obtaining unit comprises operation as the section value obtaining unit that obtains a plurality of the section values for a plurality of the arc measurement sections, and
operation as the arc determination unit comprises operation as the arc determination unit that determines the presence of the arc by comparing, as the value calculated from the section value of the arc measurement section and the section value of the noise measurement section, a ratio calculated using the plurality of the section values of the plurality of the arc measurement sections to the section value of the noise measurement section, with the predetermined threshold.

10. The arc detector according to claim 7 , wherein the processor is configured to perform operations such that:
operation as the section value obtaining unit comprises operation as the section value obtaining unit that obtains a plurality of the section values for a plurality of the arc measurement sections, and
operation as the arc determination unit comprises operation as the arc determination unit that determines the presence of the arc by comparing, as the value calculated from the section value of the arc measurement section and the section value of the noise measurement section, at least one of a ratio of a selected one of the plurality of the section values to the section value of the noise measurement section, and a difference between the selected one of the plurality of the section values and the section value of the noise measurement section, with the predetermined threshold.

11. An arc detection method, comprising:
detecting an output current from a distributed direct-current power supply;
converting the output current detected from the distributed direct-current power supply to a power spectrum;
dividing an arc measurement section for the power spectrum having a predetermined frequency range into a plurality of regions;
obtaining, from region values determined for the plurality of regions, each of the region values indicating a magnitude of the power spectrum for a respective region of the plurality of regions, and with a maximum one of the region values being excluded, a region value to be a section value of the arc measurement section; and
determining a presence of an arc by co

Assignees

• Omron Tateisi Electronics Co

Inventors

• Tomita Kohei
• Fujii Toru
• Hattori Reiko
• Ashida Takeshi

Classifications

• H02S50/00

  Monitoring or testing of PV systems, e.g. load balancing or fault identification · CPC title

• H02H7/20

  for electronic equipment (for converters H02H7/10; for electric measuring instruments G01R1/36; for DC voltage or current semiconductor regulators G05F1/569; for amplifiers H03F1/52; for electronic switching circuits H03K17/08) · CPC title

• H02H3/10

  additionally responsive to some other abnormal electrical conditions · CPC title

• G01R31/1227 Primary

  of components, parts or materials (G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16) · CPC title

• H02H3/32

  involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors · CPC title