| 摘要 |
PROBLEM TO BE SOLVED: To measure the characteristics of higher harmonics of three-phase electric power system about an aimed higher harmonic by applying a single phase electric current. SOLUTION: A single-phase electric current having two frequencies fα, fβ(fα<n.fs< f') which are obtained by increasing a system basic wave frequency fs sandwiching an aimed higher harmonic (frequency n.fs) by non-integer times is severally applied between two phases of three phase electric power system 1 as a middle higher harmonic electric current, and the measured current and voltage of each phase in a system 1 are frequency-analyzed to detect a positive phase current I1 , a positive phase voltage V1 , and a negative phase current I2 , a negative phase voltage V2 about each of frequencies fα, fβof the system 1 on the application of the current of the middle higher harmonics, and the positive phase and single phase admittances Y1 , Y2 or the positive phase and negative phase impedance Z1 , Z2 of each of frequencies fα, fβof the system 1 are obtained as Y1 =I1 /V1 , Y2 =I2 /V2 or Z1 =V1 /I1 , Z2 =V2 /I2 , and the positive phase and negative phase admittance or positive phase and negative phase impedance are obtained from the admittance Y1 , Y2 or impedance Z1 , Z2 of the frequencies fαand fβthrough interpolating computation.
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