Method and apparatus for compensation of phasor estimations
US6141196A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1998 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Mar 2, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/343
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for obtaining a power system phasor includes sampling a power system signal at instants determined by a nominal power system frequency to provide a plurality of data samples; using the data samples to estimate a phasor having an elliptical trajectory; generating a deviation formula representing a frequency deviation between actual and nominal power system frequencies; and using the deviation formula to perform a coordinate transform of the estimated phasor to provide a scaled phasor having a substantially circular trajectory. If the data samples are unevenly spaced, a method in another embodiment includes minimizing squares of errors between the unevenly spaced data samples and an approximating sinusoidal function of the data samples. Power system phasors can be used to detect turn faults by providing scaled current and voltage phasors; extracting fundamental voltage and current phasors; and applying a symmetrical component transform to the fundamental voltage and current phasors to obtain symmetrical component voltage and current phasors for use in determining the existence of a turn fault. Variance calculations and/or trigonometric function fits can be used to increase s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.