초록 ▼

Apparatus is provided for detecting the presence of a high impedance arcing fault on an electrical circuit, particularly a high voltage power line. Detection of a high impedance fault is realized by monitoring the high frequency components of the alternating current in the circuit, and evaluating th

Apparatus is provided for detecting the presence of a high impedance arcing fault on an electrical circuit, particularly a high voltage power line. Detection of a high impedance fault is realized by monitoring the high frequency components of the alternating current in the circuit, and evaluating the high frequency components of each cycle of the alternating current using a microcomputer operating in accordance with a program of instructions, to determine the occurrence of a significant increase in magnitude of the high frequency components, and then to determine whether the increase exists for a prescribed period of time and follows a prescribed pattern. The high frequency components are monitored using a current-to-voltage transducer coupled to the electrical circuit, bandpass filters coupled to the transducer, and an analog-to-digital converter providing digitized samples of the filtered transducer output voltage signal.

대표청구항 ▼

Apparatus for detecting high impedance faults on an electrical circuit having alternating current flowing therethrough, which comprises: means coupled to the electrical circuit for generating a signal indicative of the magnitude and waveform of the current in the circuit, and for removing from said

Apparatus for detecting high impedance faults on an electrical circuit having alternating current flowing therethrough, which comprises: means coupled to the electrical circuit for generating a signal indicative of the magnitude and waveform of the current in the circuit, and for removing from said generated signal the portion indicative of frequency components below a preselected frequency, so as to provide an output signal indicative of the high frequency components of the alternating current in the electrical circuit; and means receiving said output signal, for evaluating the same to determine whether the magnitude of the high frequency components of the alternating current in the electric circuit is above a prescribed level, and after determining that said components are above the prescribed level, for evaluating said output signal to further determine whether the magnitude of the high frequency components of the alternating current in the electric circuit remains above the prescribed level for at least a prescribed minimum number of cycles of the alternating current, thereby determining the existence of a high impedance fault condition on the electrical circuit.