Phasor measurement method in electric-power system

A phasor measurement and power system technology, applied in the power field, can solve the problems of rectangular window and Fourier transform multi-frequency interference, spectrum energy leakage, etc., and achieve the effect of solving high-frequency interference and spectrum energy leakage

Active Publication Date: 2014-12-03
CHINA AGRI UNIV
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Problems solved by technology

[0008] Aiming at the defects in the prior art, the present invention provides a phasor measurement method in the power system, which is used to solve the problems of more high-frequency interference and spectrum energy leakage in the rectangular window and Fourier transform in the prior art

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[0026] The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] Currently, the spectrum leakage in the sampled signal is related to the side lobes on both sides of the window function spectrum. If the height of the side lobes is lower and the main lobe is more concentrated, the spectrum leakage will be less and closer to the real spectrum.

[0028] In the prior art, the most commonly used window functions are rectangular window, Hanning window, Hamming window, Blackman window, raised cosine window (raised cosine window, RCW for short) and the like.

[0029] The advantage of the rectangular window is that the main lobe is relatively concentrated, and the disadvantage is that the side lobes are relatively high, which leads to high...

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Abstract

The invention provides a phasor measurement method in an electric-power system. The method includes the following steps: adopting a composite window used for inhibiting negative frequencies to process sampling signals; and carrying out Fourier transformation on the sampling signals processed by the composite window so that a phasor value is obtained, wherein the amplitudes of sidelobes corresponding to -48 to -52 HZ frequencies in the sampling signals processed by the composite window are smaller than a preset value. The method is capable of solving a problem, which exists in the prior art, that more high-frequency interferences and spectrum energy leakage exist in a rectangular window and Fourier transformation.

Description

technical field [0001] The invention relates to electric power technology, in particular to a phasor measurement method in an electric power system. Background technique [0002] In the photovoltaic grid-connected power generation system, the phasor value is an important observation quantity. The safety automatic device of the photovoltaic grid-connected power generation system needs to measure its value in real time, and make corresponding control measures according to the change of its value. [0003] In the prior art, the most widely used phasor measurement method under low-frequency oscillation conditions in power systems is mainly based on discrete Fourier transform (Discrete Fourier Transform, DFT) to obtain phasor values. [0004] The existing Fourier transform studies the relationship between the entire time domain and the frequency domain. In practical applications, it is impossible to measure and calculate an infinitely long signal, but to take its finite time seg...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16
Inventor 薛蕙陈娟万蓉
Owner CHINA AGRI UNIV
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