PURPOSE: To separate only fault sections without requiring service interruption for all the sections by detecting loop current flow through a loop current detection means in a section detector and opening a section switch.
CONSTITUTION: A zero-phase detecting means detects zero-phase current and zero-phase voltage of a distribution line, and when the detected zero-phase voltage and zero-phase current are higher than set values the signal processing means E311, E321, E311 in section detectors E31, E32, E33 judge the direction of ground current flow based on the zero-phase voltage and zero-phase current. When loop current is flowing between the loop current detecting means E313, E323, E333 in the section detectors E31, E32, E33 and the loop current detecting means in a section detector arranged in upstream or downstream, section switches E21, E22, E23 arranged on the distribution line are opened thus separating the fault section from sound distributing section. Through such an arrangement, only the fault section can be separated from sound sections without requiring service interruption for all the sections.
HORI KOICHI
OTSUKA MASAO
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