Method for discriminating abnormal current including arc current in AC load circuit and apparatus for executing the same

摘要

An abnormal current discriminating method including an arc current detecting method and the apparatus for performing the same in which the arc current method includes the steps of: extracting a predetermined transition pattern specified by the combination of fluctuation patterns of peak values of three continuous half waves from the peak value for each half wave detected from an alternating current flowing to the AC load circuit which is sampled in a predetermined cycle and converted into a digital value, counting the number of appearances of the predetermined transition pattern, and comparing the count value with a predetermined threshold. According to which, a series arc which may be caused in a relative small current range by an apparatus cord or the like which has not been detected by an instantaneous breaker and an arc short-circuit phenomenon generated together with an arc through the contact between the cores in a cord and an interior wiring can be detected by executing simple algorithm without error detecting.