Electric arc detection in photovoltaic installations
First Claim
1. A method for estimating a series or parallel nature and a location of an arc in a photovoltaic device, including N (N=1 or N>
- 1) strings of photovoltaic modules, connected to a charge device having a capacitive behavior for the modules, the method comprising;
a) measuring, at terminals of each of the modules of each string, evolution of voltage over time, at least during formation of an electric arc;
b) identifying modules at the terminals of which a voltage variation occurs between a first duration during which the voltage has a substantially stable slope and a second duration during which the voltage has a substantially stable slope for a duration of at least 5 μ
s, which immediately follows the voltage variation, and identifying the positive or negative direction of each voltage variation;
c) estimating the location of the arc in the photovoltaic device and whether the arc has a series or parallel nature, based on the information on the modules at the terminals of which the voltage variation occurs, and the positive or negative direction of each voltage variation; and
d) disconnecting the photovoltaic modules from other circuits connected to the photovoltaic device based on the location of the arc and the series or parallel nature of the arc,wherein, when the voltage at the terminals of a module of one of the strings of the device decreases, when the voltage at the terminals of all other modules of the same string increases, it is concluded that a parallel arc is occurring across the terminals of the module or that a series arc is occurring within the module, andwherein, when the voltage at the terminals of the module;
decreases to the arc voltage value, it is concluded that a parallel arc is occurring across the terminals of the module, anddecreases by an absolute value substantially equal to Varc/((1/nmod)−
1), wherein Varc is the final voltage of the arc, and nmod is the number of modules in the string concerned, it is concluded that a series arc is occurring within the module.
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Accused Products
Abstract
A method estimating a series or parallel nature and a location of an arc in a photovoltaic device, operating under direct current, including N (N=1 or N>1) strings of photovoltaic modules, connected to a charge device having a capacitive behaviour for the modules, the method including: a) detecting, at terminals of each of the modules of each string, evolution of voltage over time, during formation of an electric arc; b) identifying the modules at the terminals of which a voltage variation occurs 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 identifying the sign of each voltage variation; c) estimating the series or parallel nature and the location of the arc in the photovoltaic device.
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Citations
16 Claims
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1. A method for estimating a series or parallel nature and a location of an arc in a photovoltaic device, including N (N=1 or N>
- 1) strings of photovoltaic modules, connected to a charge device having a capacitive behavior for the modules, the method comprising;
a) measuring, at terminals of each of the modules of each string, evolution of voltage over time, at least during formation of an electric arc; b) identifying modules at the terminals of which a voltage variation occurs between a first duration during which the voltage has a substantially stable slope and a second duration during which the voltage has a substantially stable slope for a duration of at least 5 μ
s, which immediately follows the voltage variation, and identifying the positive or negative direction of each voltage variation;c) estimating the location of the arc in the photovoltaic device and whether the arc has a series or parallel nature, based on the information on the modules at the terminals of which the voltage variation occurs, and the positive or negative direction of each voltage variation; and d) disconnecting the photovoltaic modules from other circuits connected to the photovoltaic device based on the location of the arc and the series or parallel nature of the arc, wherein, when the voltage at the terminals of a module of one of the strings of the device decreases, when the voltage at the terminals of all other modules of the same string increases, it is concluded that a parallel arc is occurring across the terminals of the module or that a series arc is occurring within the module, and wherein, when the voltage at the terminals of the module; decreases to the arc voltage value, it is concluded that a parallel arc is occurring across the terminals of the module, and decreases by an absolute value substantially equal to Varc/((1/nmod)−
1), wherein Varc is the final voltage of the arc, and nmod is the number of modules in the string concerned, it is concluded that a series arc is occurring within the module. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- 1) strings of photovoltaic modules, connected to a charge device having a capacitive behavior for the modules, the method comprising;
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9. A device for estimating a series or parallel nature and a location of an arc in a photovoltaic system, including N (N=1 or N>
- 1) strings of photovoltaic modules, connected to a charge device having a capacitive behavior for the modules, the device comprising;
a) detectors configured to detect, at terminals of each of the modules of each string, evolution of voltage over time during formation of an electric arc; b) a data processor configured to; identify modules at the terminals of which at least one voltage variation occurs, between a first duration during which the voltage has a substantially stable slope and a second duration of at least 5 μ
s, during which the voltage has a substantially stable slope and which immediately follows the voltage variation, and identify a positive or negative direction of the voltage variation,estimate the location of the arc in the photovoltaic device, and whether the arc has a series or parallel nature, based on the information on the modules at the terminals of which the voltage variation occurs, and on the positive or negative direction of each voltage variation, and cause a switch to disconnect the photovoltaic modules from other circuits connected the photovoltaic device based on the location of the arc and the series or parallel nature of the arc, wherein, when the detectors at the terminals of one module of one of the strings of the device detect a voltage decrease, when the detectors at the terminals of all other modules of the same string detect a voltage increase over time, it is concluded that a parallel arc is occurring across the terminals of the module or that a series arc is occurring within the module, and wherein; when the detectors at the terminals of the module detect a voltage decrease over time to the arc voltage value, it is concluded that a parallel arc is occurring across the terminals of the module, and when the detectors at the terminals of the module detect a voltage decrease of an absolute value substantially equal to Varc/((1/nmod)−
1), wherein Varc is the final voltage of the arc, and nmod is the number of modules in the string concerned, it is concluded that a series arc is occurring within the module. - View Dependent Claims (10, 11, 12, 13, 14, 15)
- 1) strings of photovoltaic modules, connected to a charge device having a capacitive behavior for the modules, the device comprising;
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16. A device for estimating a series or parallel nature and a location of an arc in a photovoltaic system, including N (N=1 or N>
- 1) strings of photovoltaic modules, connected to a charge device having a capacitive behaviour for the modules, the device comprising;
a) detection means for detecting, at terminals of each of the modules of each string, evolution of voltage over time during formation of an electric arc; means for b) identifying modules at the terminals of which at least one voltage variation occurs, between a first duration during which the voltage has a substantially stable slope and a second duration of at least 5 μ
s, during which the voltage has a substantially stable slope and which immediately follows the voltage variation, and for identifying a positive or negative direction of the voltage variation, andc) estimating the location of the arc in the photovoltaic device, and whether the arc has a series or parallel nature, based on the information on the modules at the terminals of which the voltage variation occurs, and on the positive or negative direction of each voltage variation; and d) means for disconnecting the photovoltaic modules from other circuits connected to the photovoltaic device based on the location of the arc and the series or parallel nature of the arc, wherein, when the detection means at the terminals of one module of one of the strings of the device detect a voltage decrease, when the detection means at the terminals of all other modules of the same string detect a voltage increase over time, it is concluded that a parallel arc is occurring across the terminals of the module or that a series arc is occurring within the module, and wherein; when the detection means at the terminals of the module detect a voltage decrease over time to the arc voltage value, it is concluded that a parallel arc is occurring across the terminals of the module, and when the detection means at the terminals of the module detect a voltage decrease of an absolute value substantially equal to Varc/((1/nmod)−
1), wherein Varc is the final voltage of the arc, and nmod is the number of modules in the string concerned, it is concluded that a series arc is occurring within the module.
- 1) strings of photovoltaic modules, connected to a charge device having a capacitive behaviour for the modules, the device comprising;
Specification