Interharmonic detection method for eliminating interference caused by fundamental waves and harmonic waves to interharmonic detection

A harmonic detection and harmonic technology, applied in the field of inter-harmonic detection, can solve the problems of endangering the safe operation of the power supply system and affecting the stable and normal use of various electrical equipment, so as to achieve the benefits of engineering realization, high-precision detection, and increase Effect of Frequency Resolution

Active Publication Date: 2016-08-17
UNIV OF JINAN
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Problems solved by technology

It is mainly reflected in endangering the safe operation of the power supply system and affecting the stable and normal use of various electrical equipment

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  • Interharmonic detection method for eliminating interference caused by fundamental waves and harmonic waves to interharmonic detection
  • Interharmonic detection method for eliminating interference caused by fundamental waves and harmonic waves to interharmonic detection
  • Interharmonic detection method for eliminating interference caused by fundamental waves and harmonic waves to interharmonic detection

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Embodiment Construction

[0046] The present invention is described in detail below in conjunction with accompanying drawing:

[0047] 1. The principle of spectrum leakage phenomenon

[0048]Theoretically, the fast Fourier transform is to transform the entire time domain of the measured signal, but in practice, we need to perform Fourier transform on one or several periods of the measured signal. This is equivalent to adding a rectangular window whose width is its own period T to the measured signal invisibly. The result of the corresponding Fourier transform becomes the convolution of the Fourier transform of the entire time domain and the Fourier transform of the rectangular window. Let me do a specific analysis:

[0049] Suppose an infinitely long harmonic signal x m (t), the amplitude of the signal is A m , with frequency ω m , the phase angle is θ, as shown in formula (1). The result of the Fourier transform of this signal is located at ω m a spectral line at .

[0050] x m (t)=A m e j ...

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Abstract

The invention discloses an interharmonic detection method for eliminating interference caused by fundamental waves and harmonic waves to interharmonic detection. The method comprises the following steps: establishing an electric power system model, when detected signals of an electric power system only have fundamental wave and harmonic wave components, performing truncation analysis on continuous signals through a method of adding rectangular windows of M fundamental wave periods, and obtaining parameters of interharnomic waves; when the detected signals of the electric power system only include a combination of the fundamental waves, the harmonic waves and interharnomic waves with a single frequency, taking values of a frequency spectrum graph from endpoints of sidelobes, for reflecting frequency spectrum features of the inerharnomic waves; and when the fundamental waves, the harmonic waves and multiple interharmonic waves exist in the detected signals of the electric power system, constructing a new function by use of features of the frequency spectrum graph and the feature that the attenuation speeds of main lobes are faster relative to adjacent sidelobes and are successively mitigated downwards so as to enable the attention speeds to be faster. The method has the advantages of convenient realization, simple analysis and high precision and is an accurate and practical harmonic analysis algorithm. An effective method is provided for harmonic detection and analysis in the electric power system.

Description

technical field [0001] The invention relates to an inter-harmonic detection method, in particular to an inter-harmonic detection method for eliminating fundamental wave and harmonic pair inter-harmonic detection interference. Background technique [0002] With the development of power grid technology, harmonics and interharmonics have attracted more and more attention from scholars. The physical meaning of the fundamental wave is a signal whose period is equal to the longest period in a group of signals. In the power grid, it is the electric energy with a voltage frequency of 50Hz issued by an ideal power plant. The higher the purity of grid electric energy, the better, which can increase the efficiency of electric energy and prolong the service life of power system components. A harmonic is a group of sinusoidal voltages or currents whose frequency is an integer multiple of the fundamental frequency, while an interharmonic frequency is a group of sinusoidal voltages or cu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16
CPCG01R23/16
Inventor 程新功曾靖翔宗西举王成友任宏伟王洪玉王晗
Owner UNIV OF JINAN
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