| 摘要 |
PURPOSE:To discriminate the ground fault section, by combining half-wave signals of currents at two points to check to see if the counts thereof double in sound sections, paying attention to the fact that the currents at two points becomes opposite to each other in the phase when a ground fault occurs between the two points. CONSTITUTION:Current detectors 3 are mounted at both ends of one section as one span between steel towers 1 of an overhead ground wire 2 thereon 1. When a ground fault occurs between the points A and B, a part of a ground fault current flows through the overhead wire 2 to be detected with a current detector 3. Current flowing at the point A and current flowing at the point B are halfwave rectified separately when running through a light emitting diode 6 as they are opposite in the phase. The lights emitted according to the respective halfwaves transmit to an optical fiber 8 to be inputted into a ground fault section detector 9, with which the light signals are combined and thus, the frequency of the light emitted are doubled as the signal by the fullwave rectification when the currents at the points A and B are opposite to each other in the phase.
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