US 2003/0151414 A1 · Self-powered apparatus and method for optically detecting arcing faults in electric power systems in the presence of other light sources

Abstract

Arcing faults in an electric power system are detected by sensors powered by the light generated by the arcing even in the presence of background light. The sensors have one or more first photovoltaic cells energized by light passed through a first filter having a passband which includes a characteristic wavelength of the arcing material to generate a sensed light electrical signal. One or more second photovoltaic cells are energized by light filtered by a second filter having a passband not including the characteristic wavelength to generate a background light electrical signal. These two electrical signals are applied in opposition to an LED which is turned on when arcing is present. The light signal from the LED is transmitted through an optic fiber to a photoelectric circuit, which generates an arcing signal when energized. The LED may be biased toward the on condition by unfiltered additional photovoltaic cells.

Claims11

Dependent claims

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 incedent 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 incedent 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.

8 more elements

a sensor unit responsive to incedent light including light from the component generating a light signal when the incedent light contains light in a first passband including the predetermined wavelength that exceeds light in the incedent light in a second passband not including the predetermine wavelength by a selected amount, the sensor unit being powered only from the incedent light;
and
response means comprising a photoelectric device responsive to the light signal to generate an electrical arcing fault signal.

Dependencies are inferred from the claim text.

Self-powered apparatus and method for optically detecting arcing faults in electric power systems in the presence of other light sources

Life of this patent

Self-powered apparatus and method for optically detecting arcing faults in electric power systems in the presence of other light sources

Life of this patent

Abstract

Claims11