Patent ID: 6556397
Filing Date: 2003-04-29
Classification: H02H

Abstract:
A device for detecting an arc fault coupled to a conductor, the conductor coupling a source and a load in power distribution system, comprising:current detecting means which detects variance of current on the conductor and generates a current detection signal proportional to the variance of the current; signal attenuating means which attenuates the current detection signal to output a first attenuated signal; signal transforming means for removing noise from the first attenuated signal and limiting the level of the first attenuation signal to a predetermined level to produce a second attenuation signal; means for determining an arc fault occurrence, which compares the second attenuation signal with a predetermined first reference signal level and generates an arc detection signal if the level of the second attenuation signal is higher than the first reference signal level; and means for determining a trip of the conductor which integrates the arc detection signal and generates a trip signal if the integrated arc detection signal level is higher than a predetermined second reference signal level, wherein said signal transforming means comprises a rectifier, which rectifies the first attenuated signal, a first filter which remove low frequency signal components from an output signal of the rectifier, a level limiter which limits an output signal of the first filter to a predetermined level if the output signal of the first filter exceeds the predetermined level, a buffer which performs buffering of an output signal of the level limiter, and a second filter which remove low frequency signal from an output signal of the buffer.