Arc fault circuit interrupter system
First Claim
1. A circuit for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
- a filter circuit for analyzing said sensor signal to determine the presence of noise in a predetermined frequency range, and producing a corresponding filtered signal, wherein said filter circuit includes at least two bandpass filters having different passbands;
a comparator circuit for comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal, wherein said comparator circuit includes a corresponding at least two comparators, each receiving a reference threshold voltage, and each operable to compare the corresponding filtered signal to a reference threshold voltage to generate an output signal; and
a switching circuit for each of the comparators, each switching circuit receiving a plurality of threshold voltages and operating to select one of those threshold voltages as the reference threshold voltage for application to its corresponding comparator circuit.
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Accused Products
Abstract
In order to determine whether arcing is present in an electrical circuit, a sensor signal corresponding to current in said electrical circuit is processed. The sensor signal is filtered to determine the presence of noise in a predetermined frequency range and produce a corresponding filtered signal. The corresponding filtered signal is compared to a reference threshold voltage to generate an output signal potentially indicative of arcing. A selection is made of one from a plurality of available threshold voltages as the reference threshold voltage for use in the comparing operation. The detection operation supports either or both branch feeder arc fault detection and/or series arc fault detection.
258 Citations
34 Claims
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1. A circuit for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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a filter circuit for analyzing said sensor signal to determine the presence of noise in a predetermined frequency range, and producing a corresponding filtered signal, wherein said filter circuit includes at least two bandpass filters having different passbands; a comparator circuit for comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal, wherein said comparator circuit includes a corresponding at least two comparators, each receiving a reference threshold voltage, and each operable to compare the corresponding filtered signal to a reference threshold voltage to generate an output signal; and a switching circuit for each of the comparators, each switching circuit receiving a plurality of threshold voltages and operating to select one of those threshold voltages as the reference threshold voltage for application to its corresponding comparator circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A circuit for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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a filter circuit for analyzing said sensor signal to determine the presence of noise in a predetermined frequency range, and producing a corresponding filtered signal; a comparator circuit for comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal; a switching circuit receiving a plurality of threshold voltages and operating to select one of those threshold voltages as the reference threshold voltage for application to the comparator circuit; and a controller circuit for selectively controlling the switching circuit to select one of the plurality of threshold voltages as the reference threshold voltage for application to the comparator circuit; wherein the controller circuit comprises threshold register and a microprocessor, and wherein the microprocessor loads the threshold register with a value indicative of the selected one of the plurality of threshold voltages, and the switching circuit responds to the value loaded into the threshold register to make the selection.
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15. A circuit for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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a filter circuit for analyzing said sensor signal to determine the presence of noise in a predetermined frequency range, and producing a corresponding filtered signal; a comparator circuit for comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal; a switching circuit receiving a plurality of threshold voltages and operating to select one of those threshold voltages as the reference threshold voltage for application to the comparator circuit; and a controller circuit for selectively controlling the switching circuit to select one of the plurality of threshold voltages as the reference threshold voltage for application to the comparator circuit; wherein the plurality of threshold voltages include a voltage useful in detecting branch feeder arc faults in the electrical circuit and another voltage useful in detecting series arc faults in the electrical circuit.
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16. A circuit for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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a filter circuit for analyzing said sensor signal to determine the presence of noise in a predetermined frequency range, and producing a corresponding filtered signal; a comparator circuit for comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal; a switching circuit receiving a plurality of threshold voltages and operating to select one of those threshold voltages as the reference threshold voltage for application to the comparator circuit; and a controller circuit for processing said output signal to determine whether an arcing fault of the series type is present in said electrical circuit.
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17. A circuit for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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a filter circuit for analyzing said sensor signal to determine the presence of noise in a predetermined frequency range, and producing a corresponding filtered signal; a comparator circuit for comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal; and a switching circuit receiving a plurality of threshold voltages and operating to select one of those threshold voltages as the reference threshold voltage for application to the comparator circuit; wherein the plurality of threshold voltages include a voltage useful in detecting branch feeder arc faults in the electrical circuit and another voltage useful in detecting series arc faults in the electrical circuit. - View Dependent Claims (18, 19, 20)
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21. A method for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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filtering said sensor signal to determine the presence of noise in a predetermined frequency range so as to produce a corresponding filtered signal, wherein filtering comprises bandpass filtering in at least two different passbands; comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal potentially indicative of arcing, wherein comparing comprises separately first and second comparing of the corresponding filtered signals in the different passbands to at least one reference threshold voltage; and selecting individually for each of the separate first and second comparing one from a plurality of available threshold voltages as the reference threshold voltage for use in comparing. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A method for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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filtering said sensor signal to determine the presence of noise in a predetermined frequency range so as to produce a corresponding filtered signal; comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal potentially indicative of arcing; selecting one from a plurality of available threshold voltages as the reference threshold voltage for use in comparing; and selectively choosing one of the plurality of threshold voltages as the reference threshold voltage for comparing; wherein the plurality of threshold voltages include a voltage useful in detecting branch feeder arc faults in the electrical circuit and another voltage useful in detecting series arc faults in the electrical circuit.
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30. A method for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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filtering said sensor signal to determine the presence of noise in a predetermined frequency range so as to produce a corresponding filtered signal; comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal potentially indicative of arcing; selecting one from a plurality of available threshold voltages as the reference threshold voltage for use in comparing; and processing said output signal to determine whether an arcing fault of the series type is present in said electrical circuit.
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31. A method for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising:
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filtering said sensor signal to determine the presence of noise in a predetermined frequency range so as to produce a corresponding filtered signal; comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal potentially indicative of arcing; and selecting one from a plurality of available threshold voltages as the reference threshold voltage for use in comparing; wherein the plurality of threshold voltages include a voltage useful in detecting branch feeder arc faults in the electrical circuit and another voltage useful in detecting series arc faults in the electrical circuit. - View Dependent Claims (32, 33, 34)
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Specification