Alternating current series arc fault detection method
First Claim
1. A method of detecting and indicating a presence of alternating current (AC) series arc fault events in current supplied by an AC electrical power source to an electrical load for the power source, comprising the steps of:
- measuring positive and negative current through the load over a first sample cycle of the AC power to establish first measured positive and first measured negative current levels;
determining the absolute value of the first measured positive and first measured negative current levels to establish a first absolute positive current level and a first absolute negative current level;
adding the first absolute positive current level and the first absolute negative current level to establish a first sum current level;
measuring positive and negative current through the load over a second sample cycle of the AC power staggered from the first sample cycle to establish second measured positive and second measured negative current levels;
determining the absolute value of the second measured positive and second measured negative current levels to establish a second absolute positive current level and a second absolute negative current level;
adding the second absolute positive current level and the second absolute negative current level to establish a second sum current level;
subtracting the second sum current level from the first sum current level to establish a current difference level; and
indicating a series arc fault event if the current difference level exceeds a predetermined threshold level.
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Accused Products
Abstract
A method of detecting and indicating a presence of alternating current (AC) series arc fault events in current supplied by an AC electrical power source to an electrical load for the power source comprises the steps of: measuring positive and negative current through the load over a first sample cycle of the AC power to establish first measured positive and first measured negative current levels; determining the absolute value of the first measured positive and first measured negative current levels to establish a first absolute positive current level and a first absolute negative current level; adding the first absolute positive current level and the first absolute negative current level to establish a first sum current level; measuring positive and negative current through the load over a second sample cycle staggered from the first sample cycle to establish second measured positive and second measured negative current levels; determining the absolute value of the second measured positive and second measured negative current levels to establish a second absolute positive current level and a second absolute negative current level; adding the second absolute positive current level and the second absolute negative current level to establish a second sum current level; subtracting the second sum current level from the first sum current level to establish a current difference level; and indicating a series arc fault event if the current difference level exceeds a predetermined threshold level.
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Citations
24 Claims
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1. A method of detecting and indicating a presence of alternating current (AC) series arc fault events in current supplied by an AC electrical power source to an electrical load for the power source, comprising the steps of:
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measuring positive and negative current through the load over a first sample cycle of the AC power to establish first measured positive and first measured negative current levels; determining the absolute value of the first measured positive and first measured negative current levels to establish a first absolute positive current level and a first absolute negative current level; adding the first absolute positive current level and the first absolute negative current level to establish a first sum current level; measuring positive and negative current through the load over a second sample cycle of the AC power staggered from the first sample cycle to establish second measured positive and second measured negative current levels; determining the absolute value of the second measured positive and second measured negative current levels to establish a second absolute positive current level and a second absolute negative current level; adding the second absolute positive current level and the second absolute negative current level to establish a second sum current level; subtracting the second sum current level from the first sum current level to establish a current difference level; and indicating a series arc fault event if the current difference level exceeds a predetermined threshold level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Computer-readable media for storing instructions to detect and indicate a presence of alternating current (AC) series arc fault events in current supplied by an AC electrical power source to an electrical load for the power source, comprising:
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instructions to measure positive and negative current through the load over a first sample cycle of the AC power to establish first measured positive and first measured negative current levels; instructions to determine the absolute value of the first measured positive and first measured negative current levels to establish a first absolute positive current level and a first absolute negative current level; instructions to add the first absolute positive current level and the first absolute negative current level to establish a first sum current level; instructions to measure positive and negative current through the load over a second sample cycle of the AC power staggered from the first sample cycle to establish second measured positive and second measured negative current levels; instructions to determine the absolute value of the second measured positive and second measured negative current levels to establish a second absolute positive current level and a second absolute negative current level; instructions to add the second absolute positive current level and the second absolute negative current level to establish a second sum current level; instructions to subtract the second sum current level from the first sum current level to establish a current difference level; and instructions to indicate a series arc fault event if the current difference level exceeds a predetermined threshold level. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An electrical system comprising:
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an electrical alternating current (AC) load; an electrical AC power source; an electrical AC power bus for coupling power from the source to the load; and a system control unit for controlling the electrical system that detects and indicates a presence of alternating current (AC) series arc fault events in current supplied by the power source to the load; wherein the system control unit; measures positive and negative current through the load over a first sample cycle of the AC power to establish first measured positive and first measured negative current levels; determines the absolute value of the first measured positive and first measured negative current levels to establish a first absolute positive current level and a first absolute negative current level; adds the first absolute positive current level and the first absolute negative current level to establish a first sum current level; measures positive and negative current through the load over a second sample cycle of the AC power staggered from the first sample cycle to establish second measured positive and second measured negative current levels; determines the absolute value of the second measured positive and second measured negative current levels to establish a second absolute positive current level and a second absolute negative current level; adds the second absolute positive current level and the second absolute negative current level to establish a second sum current level; subtracts the second sum current level from the first sum current level to establish a current difference level; and indicates a series arc fault event if the current difference level exceeds a predetermined threshold level. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification