Harmonic characteristic measuring method and harmonic characteristic measuring apparatus
US6114859A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 13, 1998 |
| Grant date | Sep 5, 2000 |
| Priority date | — |
| Expiry date | Jul 13, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R23/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Single-phase currents at two frequencies f.alpha. and f.beta. (f.alpha.<n.multidot.fs<f.beta.) of non-integral multiples of a system fundamental wave frequency fs sandwiching an targeted harmonic (frequency n.multidot.fs) are injected between two phases of a three-phase power system as interharmonic currents. A frequency analysis of measurement current and measurement voltage of each phase in the system is carried out and a positive-phase-sequence current I1, a positive-phase-sequence voltage V1, a negative-phase-sequence current I2, and a negative-phase-sequence voltage V2 are detected for each of the two frequencies f.alpha. and f.beta. in the system based on injecting of the interharmonic currents. Positive-phase-sequence and negative-phase-sequence admittances Y1 and Y2 or positive-phase-sequence and negative-phase-sequence impedances Z1 and Z2 are found for each of the frequencies f.alpha. and f.beta. in the system as Y1=I1/V1 and Y2=I2/V2 or Z1=V1/I1 and Z2=V2/I2. Interpolation operation is performed for finding positive-phase-sequence and negative-phase-sequence admittances or positive-phase-sequence and negative-phase-sequence impedances for the targeted harmonic in the sys…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.