Non-contact arc detection apparatus and method
AssigneeElectric Power Research Institute, Inc.
InventorsDouglas Stewart Dorr, Kermit O. Phipps, Thomas A. Cooke, Francis S. Doherty, Neil Weisenfeld
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Abstract
The present invention relates to a non-contact arc detection, recognition, and warning apparatus for the detection of arcing in an electrical system. The apparatus includes an electric field detector having first and second electric field sensors adapted to sense electric fields; a magnetic field detector having a multi-axis magnetic field sensor adapted to detect a magnetic field; and a digital signal processor. The digital signal processor compares and enhances signals obtained from the electric field detector and the magnetic field detector and creates a response to alert a user of the presence of arcing.
Claims18
A non-contact arc detecting apparatus, comprising:
- (a) an electric field detector having first and second electric field sensors adapted to sense electric fields;
- (b) a magnetic field detector having a multi-axis magnetic field sensor adapted to detect a magnetic field;
- (c) a digital signal processor adapted to compare and enhance signals obtained from the electric field detector and the magnetic field detector and create a response to alert a user of the presence of arcing.
A portable non-contact arc detection, recognition, and warning apparatus, comprising:
- (a) an electric field detector having:
- (i) first and second electric field sensors adapted to sense electric fields;
- (ii) first and second AM receiver circuits electrically connected to the first and second electric field sensors to transform signals received from the first and second electric field sensors into LO-band and HI-band signals;
- (iii) first and second demodulators electrically connected to the first and second AM receiver circuits to receive the LO-band and HI-band signals and resolve audio frequencies of the LO-band and HI-band signals in the 1 Hz to about 20 KHz range to form DEMOD-LO and DEMOD-HI signals;
- (b) a magnetic field detector having:
- (i) a multi-axis magnetic field sensor adapted to detect a magnetic field;
- (ii) a first HI-pass filter electrically connected to the multi-axis magnetic field sensor to form a first buffered HI-pass signal;
- (iii) a second HI-pass filter electronically connected to the multi-axis magnetic field sensor;
- (iv) a series of 12th order notch filters electrically connected to the second HI-pass filter to form a second buffered HI-pass signal;
- (c) a digital signal processor adapted to receive the DEMOD-LO, DEMOD-HI, first buffered HI-pass, and second buffered HI-pass signals from the electric field and magnetic field detectors to compare and enhance the signals and create a response to alert a user of the presence of arcing.
A method of determining an arcing condition, comprising the steps of:
- (a) providing an arc detection device having:
- (i) an electric field detector;
- (ii) a magnetic field detector;
- (iii) a digital signal processor;
- (b) simultaneously detecting waveform signatures in both electric and magnetic fields using the electric and magnetic field detectors;
- (c) enhancing the signatures using signal processing techniques;
- (d) using the digital signal processor to form time coordinated signals of the enhanced signatures;
- (e) using the digital signal processor to compare the time coordinated signals to a third derivative signal of the magnetic field to determine arcing conditions;
- and
- (f) reporting arcing conditions to a user.
Dependencies are inferred from the claim text.