Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Parameter related to the reproduction or fidelity of a...
Patent
1993-08-23
1995-12-05
Wieder, Kenneth A.
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Parameter related to the reproduction or fidelity of a...
324 7612, 324 7621, 324605, G01R 23167, H02J 301
Patent
active
054732557
ABSTRACT:
A method for improving accuracy of estimating natural frequency of a distribution system. The estimation is performed in order to identify a rectifier load that generates harmonics due to commutation oscillation. It includes the steps of measuring a charging current flowing into a power factor improving capacitor to obtain first data, removing fundamental frequency from the first data to obtain second data, determining, from the second data, a first time at which the amplitude of commutating oscillation components takes a maximum value, picking up third data in the interval beginning from the first time and ending at a second time later than the first time by T/N, where T is the period of the fundamental frequency, and N is the number of rectifier phases, performing frequency analysis on the third data to form fourth data by expanding the third data into a Fourier series, and determining a local peak frequency, that is, the natural frequency in the fourth data. This prevents frequency components of particular orders from being emphasized, and reduces interference between the commutation oscillations, thereby making it possible to obtain a local peak value, that is, the natural frequency with ease at high accuracy.
REFERENCES:
Matsumura et al., "Study of a method for identifying the source of harmonics . . .", Technical Research Reference of the Institute of Electric Power Engineers of Japan, PE-90-90, Jul. 20, 1990.
Kunihiro Naoki
Naito Tadashi
Do Diep
Fuji Electric & Co., Ltd.
Wieder Kenneth A.
LandOfFree
Apparatus for estimating natural frequency of distribution syste does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for estimating natural frequency of distribution syste, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for estimating natural frequency of distribution syste will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1376145