| 摘要 |
PURPOSE:To make the equipment simple and inexpensive by measuring the distance to a fault point from affected current generated in the power system in case of a ground fault in one line. CONSTITUTION:A change-over switch 103 is connected to the lower position in case of a fault in one line. A multiplier 104 outputs a zero phase current I02 on the side of the sound circuit as introduced through the changeover switch 103 as 2-fold component. Then, an addition circuit 105 adds components applied from input terminals 101 and 102 and outputs I01 (zero phase current of the affected circuit)+I02. Then, an arithmetic circuit 107 divides the output component of the multiplier 104 by the output component of the addition circuit 105, subsequently, integrates the total length Lkm (total length of the parallel 2-line system) from a memory circuit 106 to compute the distance (x) to the fault point and outputs it to an output terminal 108.
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