| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and method for computing a line characteristic which can determine the line characteristic so that setting of a ground fault relay can be performed highly accurately and exactly, without performing an artificial ground fault test.SOLUTION: The device 10 for computing the line characteristic includes a resistance Rand a changeover switch SW which are connected in parallel with a GPT tertiary limiting resistance Rof a transformer 3 for grounded type instrument and connected in series with each other, an ωC measuring part 11 which is provided for measuring an ωC value (Yor Y-Y), based on tertiary voltage Vof the transformer 3 for the grounded type instrument before and after a changeover of the changeover switch SW, and a line characteristic computing part 12 which calculates a ground fault current Iof the whole power system at the time of a ground fault accident, based on the ωC value measured by the ωC measuring part 11, calculates first to nth distribution line ground fault currents flowing through first to nth distribution lines fto fat the time of the ground fault accident, based on the calculated ground fault current I, and thus calculates the line characteristic of the first to nth distribution lines f-f. |
