Electric power and electric quantity measuring method based on frequency domain analysis and sequence component analysis

A measurement method and technology of frequency domain analysis, applied in the direction of electric power measurement, spectrum analysis/Fourier analysis, and measurement devices through the application of digital technology, can solve the problems of power equipment, power users and communication lines, and analysis of out-of-sequence components Problems such as the power calculation method and the influence on the measurement accuracy of electric load power have achieved the effect of high measurement accuracy

Inactive Publication Date: 2010-07-28
HEBEI ELECTRIC POWER RES INST
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Problems solved by technology

[0002] With the development of power electronic technology, various nonlinear, non-periodic and asymmetrical loads are put into use, and the harmonic problems brought by power electronic devices pose a potential threat to the safety, stability and economic operation of the power system. The application of these technologies While improving productivity, it has brought great negative effects to the power grid, causing a large number of harmonics and negative sequences to exist in the power grid. Harmonics and negative sequences not only pose hazards to power equipment, power users and communication lines, but also Will affect the power measurement accuracy of normal electrical loads
[0003] Current measurement methods, there is no power calculation method for frequency domain analysis and sequence component analysis of harmonics and negative sequences

Method used

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  • Electric power and electric quantity measuring method based on frequency domain analysis and sequence component analysis
  • Electric power and electric quantity measuring method based on frequency domain analysis and sequence component analysis
  • Electric power and electric quantity measuring method based on frequency domain analysis and sequence component analysis

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Embodiment 1

[0015] Embodiment 1 (and make an introduction with respect to the application of DFT algorithm in the present invention):

[0016] The voltage and current signal waveforms in the electric load are all periodic non-sinusoidal waveforms and satisfy the Dirichli condition, so it can be expanded into Fourier series.

[0017] Because the main components of harmonics are mainly concentrated in the low frequency components within the 50th order. Through the DFT analysis of the common waveforms of electric loads, it is known that the DFT analysis to the 50th harmonic is enough to be close to the original waveform, and the 50th harmonic frequency is 50×50=2500HZ. According to the sampling theorem, the sampling frequency f 采 ≥2f 信号 =2×2500=5000HZ, so at least The input signal can be restored without distortion.

[0018] The following briefly introduces the calculation method of the electric power in consideration of harmonics and negative sequence in the present invention.

[0019...

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Abstract

The invention discloses an electric power and electric quantity measuring method based on frequency domain analysis and sequence component analysis, relating to the technical field of electric power and electric quantity measurement. The method comprises the following steps: firstly, processing signals of the same path of voltage and current to form analog signals, and carrying out anti-aliasing filtering on the processed voltage signals and the processed current signals to form sampling signals; carrying out analog-to-digital conversion on the sampling signals to form digital signals; computing the digital signals after analog-to-digital conversion by utilizing a discrete Fourier transformation computation method through a processor; carrying out decomposition computation of positive sequence, negative sequence and zero sequence on fundamental wave signals by utilizing a sequence component decomposition method through the processor; and comprehensively computing the digital signals after DFT and sequence component decomposition to form the following parameters: harmonic active power, positive sequence active power, negative sequence active power, zero sequence active power, total active power and electric quantity. The invention has high measuring accuracy and provides an effective method for power consumers and power supply companies to measure power consumption of electric loads comprehensively and accurately.

Description

technical field [0001] The invention relates to the technical field of electric power and electricity measurement. Background technique [0002] With the development of power electronic technology, various nonlinear, non-periodic and asymmetrical loads are put into use, and the harmonic problems brought by power electronic devices pose a potential threat to the safety, stability and economic operation of the power system. The application of these technologies While improving productivity, it has brought great negative effects to the power grid, causing a large number of harmonics and negative sequences to exist in the power grid. Harmonics and negative sequences not only pose hazards to power equipment, power users and communication lines, but also It will affect the power measurement accuracy of normal electric loads. [0003] In current measurement methods, there is no power calculation method for frequency domain analysis and sequence component analysis of harmonics and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R21/133G01R22/10G01R23/16
Inventor 段晓波胡文平
Owner HEBEI ELECTRIC POWER RES INST
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