Arc fault circuit interrupter and method of detecting and interrupting a resistive series arc of a power circuit
First Claim
1. An arc fault circuit interrupter for a power circuit including a plurality of alternating current half cycles, said arc fault circuit interrupter comprising:
- a line terminal;
a load terminal;
separable contacts electrically connected in series between said line terminal and said load terminal;
a neutral conductor;
an operating mechanism structured to open and close said separable contacts, said operating mechanism being structured to trip open said separable contacts in response to a trip signal;
a current sensor structured to sense current flowing through said separable contacts;
a voltage sensor structured to detect a plurality of voltage zero crossings between said load terminal and said neutral conductor, a consecutive pair of said voltage zero crossings defining a corresponding one of said half cycles; and
a processor cooperating with said current sensor and said voltage sensor to detect a resistive series arc in series with said separable contacts, said processor comprising a routine structured to determine, for each of said half cycles, a plurality of samples of said sensed current, an offset value from an average of a plurality of said samples of said sensed current proximate the voltage zero crossings for the corresponding one of said half cycles, a plurality of adjusted samples of said sensed current, each of said adjusted samples being a corresponding one of said samples of said sensed current adjusted by said offset value, a profile corresponding to a resistive series arc as a function of a plurality of said samples of said sensed current and said adjusted samples, and said trip signal in response to a number of occurrences of said profile for a number of said half cycles.
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Accused Products
Abstract
An arc fault circuit interrupter includes line and load terminals, separable contacts in series between the terminals, a neutral conductor, and an operating mechanism opening and closing the contacts and tripping open the contacts in response to a trip signal. A current transformer senses current flowing through the contacts. A voltage sensor detects voltage zero crossings between the load terminal and the neutral conductor. A processor detects a resistive series arc in series with the contacts. A processor routine determines, for each half cycle, samples of the sensed current, an offset value from an average of sensed current samples proximate the voltage zero crossings for the corresponding half cycle, adjusted sensed current samples as adjusted by the offset value, a profile corresponding to a resistive series arc as a function of the sensed current samples and the adjusted samples, and the trip signal in response to occurrences of the profile.
10 Citations
23 Claims
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1. An arc fault circuit interrupter for a power circuit including a plurality of alternating current half cycles, said arc fault circuit interrupter comprising:
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a line terminal; a load terminal; separable contacts electrically connected in series between said line terminal and said load terminal; a neutral conductor; an operating mechanism structured to open and close said separable contacts, said operating mechanism being structured to trip open said separable contacts in response to a trip signal; a current sensor structured to sense current flowing through said separable contacts; a voltage sensor structured to detect a plurality of voltage zero crossings between said load terminal and said neutral conductor, a consecutive pair of said voltage zero crossings defining a corresponding one of said half cycles; and a processor cooperating with said current sensor and said voltage sensor to detect a resistive series arc in series with said separable contacts, said processor comprising a routine structured to determine, for each of said half cycles, a plurality of samples of said sensed current, an offset value from an average of a plurality of said samples of said sensed current proximate the voltage zero crossings for the corresponding one of said half cycles, a plurality of adjusted samples of said sensed current, each of said adjusted samples being a corresponding one of said samples of said sensed current adjusted by said offset value, a profile corresponding to a resistive series arc as a function of a plurality of said samples of said sensed current and said adjusted samples, and said trip signal in response to a number of occurrences of said profile for a number of said half cycles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of detecting and interrupting a resistive series arc of a power circuit including a plurality of alternating current half cycles, said method comprising:
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sensing current flowing through said power circuit; detecting a plurality of voltage zero crossings of said power circuit, a consecutive pair of said voltage zero crossings defining a corresponding one of said half cycles; determining, for each of said half cycles, a plurality of samples of said sensed current, an offset value from an average of a plurality of said samples of said sensed current proximate the voltage zero crossings for the corresponding one of said half cycles, a plurality of adjusted samples of said sensed current, each of said adjusted samples being a corresponding one of said samples of said sensed current adjusted by said offset value, a profile corresponding to a resistive series arc as a function of a plurality of said samples of said sensed current and said adjusted samples, and a trip signal in response to a number of occurrences of said profile for a number of said half cycles; and interrupting said power circuit responsive to said trip signal. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification