To provide an apparatus which facilitates determining the presence of a ground-fault current of a resistance value and value reliability and is practical and economical.
An apparatus such as a molded case circuit breaker, a ground-fault interrupter, a relay, and a measuring instrument provided with a means for detecting a ground leakage current of an electrical path and detecting the magnitude of a leakage current due to a resistance ground fault on the basis of a phase shift between its magnitude and a voltage of the electrical path is provided with a means for detecting a ground-fault current of the resistance value, displaying or outputting its magnitude each time, and displaying or outputting an error range of computation results corresponding to the magnitude of the phase shift between the ground leakage current and the voltage of the electrical path together.
COPYRIGHT: (C)2009,JPO&INPIT
Kenji Nakata
Masao Imamoto
Shigeru Aihara
Hayashi Tadataka
Takanori Aoki
Kenji Ando
Hironori Azuma
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