| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an earth fault detection device capable of identifying an earth-fault steel tower in an extra-high-voltage transmission system whose neutral point on a transmission side is directly grounded. <P>SOLUTION: Surge absorbers 140 and 142 are provided with, besides a function for suppressing outputs of detecting coil parts 1 and 2 that have detected a fault current in earth fault, a function of reducing magnetic saturation of the first and second detecting coil parts 1 and 2, and are configured to have nonmagnetic air core parts between a core 7 and a coil 9 wound around the core 7. When the output waveforms of the first and second detecting coil parts 1 and 2 are distorted, the earth fault detection device improves the distortion of a fault current in the earth fault on the basis of the outputs of the nonmagnetic air core parts of the first and second detecting coil parts 1 and 2 so as to enable phase detection. <P>COPYRIGHT: (C)2013,JPO&INPIT |
