Arc fault detection based on photovoltaic operating characteristics and extraction of pink noise behavior
AssigneesMERSEN USA EP Corp., Northeastern University
InventorsRoy A. Ball, Jonathan C. Kim, Bradley M. Lehman
Life of this patent
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Abstract
Pink noise analysis, along with unique properties of the photovoltaic (PV) operating point of both the instantaneous current and voltage signal, is used to distinguish arc faults from other noisy loads or PV degradations.
Claims21
A method for detecting arc faults in a photovoltaic (PV) string connected to a load, wherein a voltage sensor and a current sensor are electrically connected to the PV string and operative to measure a voltage and current, respectively, supplied to the load, the method comprising:
- measuring, using the voltage sensor, a voltage output by the PV string over a prescribed time period to obtain a data set of voltage measurements;
- measuring, using the current sensor, a current output by the PV string over the prescribed time period to obtain a data set of current measurements;
- determining if the data set of voltage measurements and the data set of current measurements are simultaneously decreasing within the prescribed time period;
- using a pink noise detector to analyze the data set of current measurements and the data set of voltage measurements for the presence of pink noise within the prescribed time period;
- and
- concluding an arc fault has occurred when
- i) the pink noise detector indicates pink noise is present during the prescribed time period, and
- ii) at least a portion of the data set of voltage measurements and at least a portion of the data set of current measurements are simultaneously decreasing while pink noise is present.
An arc fault detection system, comprising:
- a voltage sensor connectable to a photovoltaic (PV) string;
- a current sensor connectable to a PV string;
- and
- a controller communicatively coupled to the voltage sensor and the current sensor to receive voltage measurements and current measurements therefrom, the controller configured to:
- obtain from the voltage sensor a voltage output by the PV string over a prescribed time period to obtain a data set of voltage measurements;
- obtain from the current sensor a current output by the PV string over the prescribed time period to obtain a data set of current measurements;
- determine if the data set of voltage measurements and the data set of current measurements are simultaneously decreasing within the prescribed time period;
- analyze the data set of current measurements and the data set of voltage measurements for the presence of pink noise within the prescribed time period;
- and
- output an indication of an arc fault when
- i) pink noise is present during the prescribed time period, and
- ii) at least a portion of the data set of voltage measurements and at least a portion of the data set of current measurements are simultaneously decreasing while pink noise is present.
A controller for detecting the occurrence of an arc fault in a photovoltaic (PV) string, the controller configured to:
- obtain a voltage output by the PV string over a prescribed time period to obtain a data set of voltage measurements;
- obtain a current output by the PV string over the prescribed time period to obtain a data set of current measurements;
- determine if the data set of voltage measurements and the data set of current measurements are simultaneously decreasing within the prescribed time period;
- analyze the data set of current measurements and the data set of voltage measurements for the presence of pink noise within the prescribed time period;
- and
- output an indication of an arc fault when
- i) pink noise is present during the prescribed time period, and
- ii) at least a portion of the data set of voltage measurements and at least a portion of the data set of current measurements are simultaneously decreasing while pink noise is present.
Dependencies are inferred from the claim text.