| 摘要 |
PROBLEM TO BE SOLVED: To provide a testing device of cable runs in a distribution board which can accurately detect the existence of short-circuit in the cable runs at a low-voltage side, when starting the use of an apparatus, after the end of the construction and inspection thereof in the distribution board equipment (a low-voltage distribution board for feeding a low AC voltage), installed in a substation or a distributing substation. SOLUTION: When the existence or the absence of short-circuit failure in the cable runs R, S and T at the low-voltage side in the distribution board 21 is to be detected, the testing device 1 of the cable runs in the distribution board applies AC voltages of high frequencies (frequencies higher than actual working frequency (rated frequency)) which are low in the risk of an iron core of a transformer 22 becoming saturated, in clearances between the electrical paths (between R-S phases, S-T phases, or T-R phases) at the low-voltage side. Then, when an inter-phase short-circuit or a high-resistance short-circuit caused by a foreign matter between and among the cable runs R, S and T in the distribution board 21 is generated, a phase determining section 14 determines the existence of the short-circuit failures, by utilizing the effect where the phase of a current which flows approaches 0 degree with respect to the applied voltage, the smaller the short-circuit resistance value is. COPYRIGHT: (C)2011,JPO&INPIT
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