Parallel arc detection using discrete wavelet transforms
First Claim
1. An apparatus for interrupting current in an electrical circuit, the apparatus comprising:
- a current sensing device disposed in the electrical circuit to sense an electrical load, the current sensing device configured to produce an output signal representative of a load current passing therethrough;
a detection unit, in signal communication with the current sensing device and configured to receive the output signal produced by the current sensing device, the detection unit being configured and disposed to output a secondary signal based on the output signal, the secondary signal comprising a positive half cycle and a negative half cycle; and
a microcontroller coupled to the detection unit, being responsive to computer executable instructions which, when executed by the microcontroller, cause the microcontroller to receive and to decompose the secondary signal for the positive half cycle via discrete wavelet transforms to thereby obtain discrete wavelet coefficients for the positive half cycle, and to decompose the secondary signal for the negative half cycle via discrete wavelet transforms to thereby obtain discrete wavelet coefficients for negative half cycle, and to compute a sum of the discrete wavelet coefficients for the positive half cycle and the negative half cycle, and to compare the sum of the discrete wavelet coefficients for the positive half cycle and the negative half cycle to a predetermined threshold, and to generate a trip signal when the sensed load current is above a predetermined threshold and the sum of the discrete wavelet coefficients for at least one of the positive half cycle and the negative half cycle cooperatively indicate that predetermined threshold conditions for trip signal generation are satisfied.
2 Assignments
0 Petitions
Accused Products
Abstract
An apparatus to perform parallel arc fault current interruption (AFCI) is provided. The apparatus includes a current sensing device disposed in the electrical circuit, a detection unit configured to receive an output signal produced by the current sensing device and to output a secondary signal based on the output signal, a microcontroller coupled to the detection unit, configured to receive and to decompose the secondary signal via discrete wavelet transforms to thereby obtain discrete wavelet coefficients, to compute a sum of the discrete wavelet coefficients, and to compare the sum of the discrete wavelet coefficients to a predetermined threshold, and to generate a trip signal when the sensed load current is above a predetermined threshold and the sum of the discrete wavelet coefficients cooperatively indicate that predetermined threshold conditions are satisfied.
-
Citations
17 Claims
-
1. An apparatus for interrupting current in an electrical circuit, the apparatus comprising:
-
a current sensing device disposed in the electrical circuit to sense an electrical load, the current sensing device configured to produce an output signal representative of a load current passing therethrough; a detection unit, in signal communication with the current sensing device and configured to receive the output signal produced by the current sensing device, the detection unit being configured and disposed to output a secondary signal based on the output signal, the secondary signal comprising a positive half cycle and a negative half cycle; and a microcontroller coupled to the detection unit, being responsive to computer executable instructions which, when executed by the microcontroller, cause the microcontroller to receive and to decompose the secondary signal for the positive half cycle via discrete wavelet transforms to thereby obtain discrete wavelet coefficients for the positive half cycle, and to decompose the secondary signal for the negative half cycle via discrete wavelet transforms to thereby obtain discrete wavelet coefficients for negative half cycle, and to compute a sum of the discrete wavelet coefficients for the positive half cycle and the negative half cycle, and to compare the sum of the discrete wavelet coefficients for the positive half cycle and the negative half cycle to a predetermined threshold, and to generate a trip signal when the sensed load current is above a predetermined threshold and the sum of the discrete wavelet coefficients for at least one of the positive half cycle and the negative half cycle cooperatively indicate that predetermined threshold conditions for trip signal generation are satisfied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A computer implemented method of performing arc fault current interruption (AFCI) for a circuit, the method comprising:
-
sensing a load current at a current sensing device in electrical communication with the circuit; generating a secondary signal comprising a positive half cycle and a negative half cycle and being reflective of a current of the sensed load current at a detection unit in signal communication with the current sensing device; sampling the positive half cycle of the secondary signal at a predetermined frequency at a microcontroller coupled to the detection unit; sampling the negative half cycle of the secondary signal at a predetermined frequency at a microcontroller coupled to the detection unit; determining the magnitude of the secondary signal; computing discrete wavelet coefficients from the positive half cycle components of the secondary signal computing discrete wavelet coefficients from the negative half cycle components of the secondary signal; computing a sum of the computed positive half cycle and the negative half cycle discrete wavelet coefficients; comparing the sum of the computed positive half cycle and the negative half cycle discrete wavelet coefficients to a predetermined threshold; determining if threshold criteria have been met based on the magnitude of the secondary signal and at least one of the sum of the positive half cycle or the negative half cycle discrete wavelet coefficients; and
if so,issuing a trip signal to interrupt an operation of the circuit. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
-
Specification