Abstract: The present invention relates to an fault electric arc protection circuits which comprising a power source, a signal sampling device, a signal processing module, an arc detection control device and a power cut-off module. This invention also provides a method for detecting arc-fault, comprising the steps of S1, sampling the current signal of the circuits to be protected in real time, and outputting the sampled signal; S2, processing the sampled signal, then outputting the processed result; S3, detecting the processed result, and then determining whether an arc symbol has occurred based on the detected result. The advantages of the present invention is, when using the electric equipment, once a continuous fault electric arc occurred in the wires, the protection circuits can detect the fault electric are and cut off the power, thus to prevent the fire caused by the fault electric arc.

Abstract: The present invention relates to an fault electric arc protection circuits which comprising a power source, a signal sampling device, a signal processing module, an arc detection control device and a power cut-off module; the signal sampling device comprising a matching resistor R3 and a current transformer without iron core; the signal processing module comprising a rectifying tube D1 and a voltage divider R2; the arc detection control device is a SCM; the power cut-off module comprising a set of audion that orderly connected, and an actuator portion; one end of the current transformer is grounded and the other end is connected to the rectifying tube D1 thus to connect to the SCM; the matching resistor R3 is parallelly connected between the rectifying tube D1 and the current transoformer, and the voltage divider R2 is parallelly connected between the rectifying tube D1 and the SCM.