METHOD AND APPARATUS FOR DETECTION OF RESISTIVE FAULT CONDITIONS
First Claim
1. A resistive fault condition detector for conducting at least one test of a circuit comprising a live conductor, a neutral conductor, a ground conductor, and a load, the detector comprising:
- means for determining changes in current through the load during said at least one test;
means for measuring changes in first and second voltages respectively between the live and neutral conductors and between the neutral and ground conductors during said at least one test, said changes in said first and second voltages corresponding to said changes in said current respectively;
means for calculating apparent source impedances for the live and neutral conductors respectively based on said changes in said current and said measured changes in said first and second voltages respectively; and
means for calculating an estimated source impedance for each of said live and neutral conductors respectively for said at least one test.
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Abstract
A resistive fault condition detector for conducting one or more tests of a circuit to detect a resistive fault condition. The detector includes means for determining changes in current through a load during the test, and means for measuring changes in first and second voltages respectively between the circuit'"'"'s live and neutral conductors and between the circuit'"'"'s neutral and ground conductors during the test, the changes in the first and second voltages corresponding to the changes in the current respectively. The detector also includes means for calculating apparent source impedances for the live and neutral conductors respectively, based on the changes in current and the measured changes in the first and second voltages respectively, and means for calculating an estimated source impedance for each of the live and neutral conductors for the test.
25 Citations
33 Claims
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1. A resistive fault condition detector for conducting at least one test of a circuit comprising a live conductor, a neutral conductor, a ground conductor, and a load, the detector comprising:
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means for determining changes in current through the load during said at least one test; means for measuring changes in first and second voltages respectively between the live and neutral conductors and between the neutral and ground conductors during said at least one test, said changes in said first and second voltages corresponding to said changes in said current respectively; means for calculating apparent source impedances for the live and neutral conductors respectively based on said changes in said current and said measured changes in said first and second voltages respectively; and means for calculating an estimated source impedance for each of said live and neutral conductors respectively for said at least one test. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for conducting at least one test to detect a resistive fault condition in a circuit comprising a live conductor, a neutral conductor, a ground conductor, and a load, the method comprising:
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(a) determining changes in current through the load during said at least one test; (b) measuring changes in first and second voltages respectively between the live and neutral conductors and between the neutral and ground conductors during said at least one test, said changes in said first and second voltages corresponding to said changes in said current respectively; (c) calculating apparent source impedances for the live and neutral conductors respectively based on said changes in said current and said measured changes in said first and second voltages respectively; and (d) calculating an estimated source impedance for each of said live and neutral conductors respectively for said at least one test. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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30. A resistive fault condition detector for conducting at least one test of a circuit comprising a live conductor, a neutral conductor, a ground conductor, and a load, the detector comprising:
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means for initiating said at least one test; means for determining a change in current through the load during said at least one test; means for measuring a change in each of first and second voltages respectively between the live and neutral conductors and between the neutral and ground conductors during said at least one test, said changes in each of said first and second voltages corresponding to said change in said current; means for calculating at least one apparent source impedance for each of the live and neutral conductors respectively based on said change in said current and said measured changes in said first and second voltages; means for calculating an estimated source impedance for each of said live and neutral conductors respectively for said at least one test; and means for generating an alarm signal if any one of the respective estimated source impedances for the live conductor and the neutral conductor exceeds a respective predetermined threshold value therefor.
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31. A resistive fault condition detector for conducting at least one test of a circuit comprising a live conductor, a neutral conductor, a ground conductor, and a load, the detector comprising:
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means for initiating said at least one test; means for determining a change in current through the load during said at least one test; means for measuring a change in each of first and second voltages respectively between the live and neutral conductors and between the neutral and ground conductors during said at least one test, said changes in each of said first and second voltages corresponding to said change in said current; means for calculating at least one apparent source impedance for each of the live and neutral conductors respectively based on said change in said current and said measured changes in each of said first and second voltages; means for calculating an estimated source impedance for each of said live and neutral conductors respectively for said at least one test; and means for determining an imbalance between the respective estimated source impedances for the live and neutral conductors. - View Dependent Claims (32)
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33. A resistive fault condition detector for monitoring a circuit comprising a live conductor, a neutral conductor, a ground conductor, and a load, the detector comprising:
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means for determining changes in current through the load; means for measuring changes in first and second voltages respectively between the live and neutral conductors and between the neutral and ground conductors, said changes in said first and second voltages corresponding to said changes in said current respectively; means for calculating apparent source impedances for the live and neutral conductors respectively based on said changes in said current and said measured changes in said first and second voltages respectively; and means for calculating estimated source impedances for said live and neutral conductors respectively.
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Specification