Parallel electric arc detection across the main terminals of a photovoltaic installation

Patent metadata

Field	Value
Publication number	US-9843288-B2
Application number	US-201414915504-A
Country	US
Kind code	B2
Filing date	Aug 27, 2014
Priority date	Aug 29, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

A method detecting a parallel arc in a photovoltaic device, including N (N=1 or N>1) photovoltaic modules, connected to a charge device having a capacitive behavior for the modules, the method including: a) detecting, across main terminals of the device, evolution of voltage over time, at least during formation of the electric arc; b) identifying a negative voltage variation between a first zone with stable voltage and a second zone with stable voltage for a duration of at least 5 μs, which immediately follows the voltage variation, and c) determining whether the voltage variation is between a maximum value Vmax, greater than or equal to 100 V, and a minimum value Vmin, less than or equal to 30 V, with a fall time of this variation between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.

First claim

The invention claimed is:

1. A method for detecting a parallel arc in a photovoltaic device, including N (N=1 or N>1) photovoltaic modules, connected to a charge device having a capacitive behavior for the modules, the method comprising:
a) detecting, by a detector and across main terminals of the photovoltaic device, evolution of voltage over time;
b) identifying, by a data processor, a negative voltage variation between a first zone, during which the voltage has a substantially stable slope and a second zone, during which the voltage has a substantially stable slope for a duration of at least 5 μs, which immediately follows the voltage variation; and
c) determining, by the data processor, whether the voltage variation is between a maximum value Vmax, greater than or equal to 100 V, and a minimum value Vmin, less than or equal to 30 V, with a fall time of this variation between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.

2. The method according to claim 1 , wherein the determining c) takes place:
by analyzing the slope of the voltage variation and determining whether this slope is between:
a minimum value, given by the ratio of Vmin/Tmax,
and a maximum value, given by the ratio of Vmax/Tmin;
and, by determining whether the voltage variation is between a minimum value Vmin, less than or equal to 30 V, and a maximum value Vmax, greater than or equal to 100 V, or whether a rise time of the variation is between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.

3. The method according to claim 1 , wherein passive and/or active filtering of the evolution of the voltage over time takes place.

4. The method according to claim 1 , wherein the evolution of the voltage over time is digitized, whereby the a) to c) are performed based on digital voltage values.

5. The method according to claim 1 , wherein the charge device includes a converter, an inverter, or a battery.

6. The method according to claim 1 , wherein a current in the photovoltaic device is a direct current.

7. A device for detecting a parallel arc in a photovoltaic device, including N (N=1 or N>1) photovoltaic modules, connected to a charge device having a capacitive behaviour for the modules, the device comprising:
a) means for detecting, across main terminals of the photovoltaic device, evolution of voltage over time;
b) means for identifying a negative voltage variation between a first zone, during which the voltage has a substantially stable slope and a second zone, during which the voltage has a substantially stable slope for a duration of at least 5 μs, which immediately follows the voltage variation; and
c) means for determining whether the voltage variation is between a maximum value Vmax, greater than or equal to 100 V, and a minimum value Vmin, less than or equal to 30 V, with a fall time of the variation between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.

8. The device according to claim 7 , wherein the means for determining determines whether the voltage variation is between the maximum value Vmax and the minimum value Vmin, with a fall time for the variation of between Tmin and Tmax:
by analyzing the slope of the voltage variation and determining whether the slope is between:
a minimum value, given by the ratio of Vmin/Tmax,
and a maximum value, given by the ratio of Vmax/Tmin;
and, by determining whether the voltage variation is between a minimum value Vmin, less than or equal to 30 V, and a maximum value Vmax, greater than or equal to 100 V, or whether a rise time of the variation is between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.

9. The device according to claim 7 , further comprising means for removing frequencies at least equal to 100 Hz from the evolution of the voltage over time.

10. The device according to claim 7 , further comprising means for passive and/or active filtering of the evolution of the voltage over time.

11. The device according to claim 7 , further comprising means for analog and digital filtering of the evolution of the voltage over time.

12. The device according to claim 7 , further comprising means for digitizing voltages measured.

13. The device according to claim 7 , wherein the charge device having a capacitive behaviour for the modules includes a converter, an inverter, or a battery.

14. A device for detecting a parallel arc in a photovoltaic device, including N (N=1 or N>1) photovoltaic modules, connected to a charge device having a capacitive behaviour for the modules, the device comprising:
a) a detector to detect, across main terminals of the photovoltaic device, evolution of voltage over time;
b) a data processor configured to:
identify a negative voltage variation between a first zone, during which the voltage has a substantially stable slope and a second zone, during which the voltage has a substantially stable slope for a duration of at least 5 μs, which immediately follows the voltage variation, and
determine whether the voltage variation is between a maximum value Vmax, greater than or equal to 100 V, and a minimum value Vmin, less than or equal to 30 V, with a fall time of this variation between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.

15. The device according to claim 14 , wherein the data processor determines whether the voltage variation is between the maximum value Vmax and the minimum value Vmin, with a fall time for the variation of between Tmin and Tmax:
by analyzing the slope of the voltage variation and determining whether this slope is between:
a minimum value, given by the ratio of Vmin/Tmax,
and a maximum value, given by the ratio of Vmax/Tmin;
and, by determining whether the voltage variation is between a minimum value Vmin, less than or equal to 30 V, and a maximum value Vmax, greater than or equal to 100 V, or whether a rise time of the variation is between a minimum duration Tmin greater than or equal to 0.01 μs and a maximum duration Tmax less than or equal to 10 μs.

16. The device according to claim 14 , further comprising at least a filter removing frequencies at least equal to 100 Hz from the evolution of the voltage over time.

17. The device according to claim 14 , further comprising at least one of a passive and active filter to filter the evolution of the voltage over time.

18. The device according to claim 14 , further comprising at least one of an analog and digital filter to filter the evolution of the voltage over time.

19. The device according to claim 14 , further comprising a converter to digitize the evolution of the voltage over time.

20. The device according to claim 14 , wherein the charge device having a capacitive behavior for the modules includes a converter, an inverter, or a battery.

Assignees

• Commissariat Energie Atomique
• Commissariat L Energie Atomique Et Aux Energies Alternatives

Inventors

• Chaintreuil Nicolas
• Plissonnier Alexandre

Classifications

• G01R31/26

  Testing of individual semiconductor devices (testing of photovoltaic devices H02S50/10; testing or measuring during manufacture or treatment {H10P74/00}) · CPC title

• H02S50/10 Primary

  Testing of PV devices, e.g. of PV modules or single PV cells (testing of semiconductor devices during manufacturing {H10P74/00}) · CPC title

• H02S50/00

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

• Y02E10/50

  Photovoltaic [PV] energy · CPC title