Patent ID: 6693438
Filing Date: 2004-02-17
Classification: H02H

Abstract:
Apparatus for detecting an arcing fault at a component of an electric power system where the arcing fault generates light at a predetermined wavelength in the presence of light from other sources which may include the predetermined wavelength, the apparatus comprising:a sensor unit comprising: first photovoltaic means for generating a sensed light electrical signal from incident light including light from the component in a first wavelength band including the predetermined wavelength; second photovoltaic means for generating a background light electrical signal from incident light including light from the component in a second wavelength band not including the predetermined wavelength; an electrically activated light-emitting device for emitting a light signal when electrically activated; and circuit means connecting the first photovoltaic means and the second photovoltaic means to the light-emitting device with the sensed light electrical signal and the background light electrical signal in opposition to electrically activate the light-emitting device to emit the light signal when the sensed light electrical signal exceeds the background light electrical signal by a threshold amount indicative of an arcing fault; and a response unit comprising: an optic fiber transmitting the light signal from the light-emitting device; and photoelectric means responsive substantially only to the light signal transmitted by the optic fiber for generating an arcing signal in response to the light signal.