| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and a method for measuring leak current, which can enhance reliability in measurement values of the leak current flowing through ground insulating resistance of a load system connected with power distribution line fed from 400 V class star-shaped distribution power source. SOLUTION: The device includes a processing operation part 16, being equipped with a fundamental wave processor 3, which makes signal processing of voltage to ground of any one phase among three phases input from the star-shaped distribution power source 1, line voltage between any 2 lines among 3 lines, and zero phase current I<SB>0</SB>detected from the power distribution line 4 by a zero phase current transformer 9, and then measures phase difference between input voltage and the zero phase current I<SB>0</SB>to make signal processing, and an operation part 14. The operation part 14 calculates a phase angle θ to the input voltage of the zero phase current I<SB>0</SB>and computes both active and reactive elements to the input voltage from both the phase angle θ and value of the zero phase current I<SB>0</SB>. Thus the value of total leak current Igr for each phase excluding one sound phase and its reliability are calculated from the effective value of the computed elements. This value of leak current Igr and an imbalance differential current value derived from imbalance of ground capacitance are displayed on a display part 15. COPYRIGHT: (C)2010,JPO&INPIT |
