| 摘要 |
PROBLEM TO BE SOLVED: To detect a serial arc and an arc short circuit, which have been hitherto undetectable, by the use of a simple algorithm without falsely detecting a normal load current. SOLUTION: There are provided a detecting method for an abnormal current including an arc current in an AC load circuit and a device for implementing the method. The arc current detecting method includes: a step for extracting a prescribed transitional pattern specified by the combination of a variation pattern of every consecutive three half-waves detected every half-wave from a current that is sampled at prescribed cycles, converted to a digital value and made to flow into the AC load circuit; a step for counting the number of occurrences of the patterns every prescribed limit section; and a step for comparing the counted value with a prescribed threshold and discriminating abnormality when the counted value exceeds the threshold. By this method, the serial arc generated in G relatively small current area, i.e., in an apparatus cord or the like, and an arc short-circuit accident accompanying an arc generated by a touch of each core wire in the cord or in-door wiring can correctly be detected.
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