Method for analyzing electric network waveform distortions and automatically monitoring electric power harmonic parameters

A technology for automatic monitoring of power harmonics, applied in the direction of measuring electrical variables, measuring current/voltage, spectrum analysis/Fourier analysis, etc.

Inactive Publication Date: 2012-02-01
CHINA UNIV OF MINING & TECH
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Problems solved by technology

Many scholars have effectively improved the accuracy of harmonic estimation by using the window interpolation method [1~6], but with the increase of the order of the interpolation correction curve fitting function and the increase of the number of harmonics , the accuracy of harmonic estimation is improved and the amount of calculation is greatly increased

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  • Method for analyzing electric network waveform distortions and automatically monitoring electric power harmonic parameters
  • Method for analyzing electric network waveform distortions and automatically monitoring electric power harmonic parameters
  • Method for analyzing electric network waveform distortions and automatically monitoring electric power harmonic parameters

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Embodiment Construction

[0029] In order to achieve the above object, the implementation of the present invention can directly use a voltage divider or obtain the busbar voltage signal of the power grid from the secondary side of the voltage transformer PT, obtain the current signal from the current transformer CT, and send the signal sampling after appropriate signal conditioning Entrance.

[0030] Step a. Sampling the voltage or current of the power signal to be analyzed, and press figure 1 The process calculates its Chirp-Z Transform or CZT value , take a natural positive integer, and then calculate the fundamental wave parameters, amplitude, frequency and phase of the power signal by formula 1, formula 2 and formula 3;

[0031] Estimate the fundamental amplitude: Formula 1

[0032] Estimate the fundamental frequency value: f 1 =(θ+k’Ф) / 2 Formula 2

[0033] Estimate the fundamental phase value: Formula 3

[0034] In the above 3 formu...

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Abstract

The invention discloses a method for analyzing electric network waveform distortions and automatically monitoring electric power harmonic parameters, and is applicable for analyzing and monitoring harmonic waves of voltage and current of an electric network. The method comprises the following steps of: firstly, highly-precisely extracting fundamental wave signal parameters (amplitude, frequency and phase) from electric power signals containing harmonic waves by using linear frequency modulation Z transform (Chirp-ZTransform or CZT); secondly, subtracting fundamental wave signals from the analyzed electric power signals, adding Blackman window function interception electric power signals, and calculating the frequency spectrum of remaining signals by using fast Fourier transform (FFT); thirdly, precisely calculating the frequency value of each harmonic wave according to the fundamental wave frequency; and finally, interpolating a Blackman window function in a frequency domain accordingto each harmonic wave frequency, and precisely calculating parameters of each electric power harmonic wave. Compared with a method for analyzing the electric power harmonic waves by adding Blackman window FFT double spectral line interpolation fitting, the method provided by the invention has basically equivalent estimated value precision, and the amount of calculation is about 1 / 2.

Description

Technical field [0001] The invention involves an analysis and automatic monitoring algorithm of a grid voltage and current waveform distortion, which can be used for analysis instruments and automatic monitoring devices for various grid voltage and current waveform distortion.It belongs to the field of power measurement and automation technology. Background technique [0002] With the development of power electronics technology and devices, the application of non -linear loads in power systems is becoming more and more widespread. Harmony pollution of power systems is becoming increasingly serious. Harmony has become the main problem that affects the quality of electrical energy.The high -precision estimation of the harmonic component parameters will be conducive to the assessment of electrical energy quality and the corresponding necessary governance measures. [0003] Quick Fourier Transformation (FFT) is the fastest tool in harmonious analysis.However, the premise of FFT accur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16G01R19/00G01R25/00
Inventor 唐轶陈奎秦媛倩王涛杨洛尹远张跃陈雷渐伟周斌
Owner CHINA UNIV OF MINING & TECH
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