Device and method for detecting arc fault

摘要

A device for detecting arc fault which distinguishes harmful arc from the signal generated by operation of a dimmer and start of electronic devices. Signals outputted from a current transformer is attenuated by a resistor which is coupled in parallel to the current transformer. By the attenuation of the resistor, the signal generated by the operation of a dimmer is not determined to be arc in arc determining part. Harmful arc and the signal generated by the start of the electronic device are distinguished by integrating both signals. As the harmful arc lasts for a long time, large signals are integrated in an integrator while the signal generated by the start of electronic device does not last for a long time.