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Improved phase difference correction method taking regard of power grid frequency change rate

A technology for grid frequency and frequency correction, applied in spectrum analysis/Fourier analysis and other directions, which can solve problems such as harmonic parameter measurement errors

Active Publication Date: 2017-07-21
ZHEJIANG UNIV
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Problems solved by technology

Fast Fourier transform (FFT) is one of the commonly used algorithms for power harmonic parameter measurement. Under synchronous sampling, the parameters of each harmonic can be accurately obtained, but under non-synchronous sampling, the spectrum leakage and frequency Due to the fence effect caused by domain discretization, there will be large errors in the measurement of harmonic parameters

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  • Improved phase difference correction method taking regard of power grid frequency change rate
  • Improved phase difference correction method taking regard of power grid frequency change rate
  • Improved phase difference correction method taking regard of power grid frequency change rate

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Embodiment Construction

[0068] In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific preferred examples.

[0069] The improved phase difference correction method of the present invention can be applied to the online measurement of power harmonics, wherein the frequency change rate of the fundamental wave ROCOF 1 (i.e. df 1 / dt) is an important parameter, which is obtained by dividing the difference between the two measured fundamental frequencies by the time interval between the two measurements, that is, the difference quotient between the previous and current measured fundamental frequencies.

[0070] Introduce two kinds of concrete implementation methods that use the improved phase difference correction method of the present invention to carry out on-line measurement below:

[0071] combined with figure 1 Explain the measurement process of method 1...

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Abstract

The invention discloses an improved phase difference correction method taking regard of the power grid frequency change rate. With respect to the improved phase difference correction method, based on the frequency change rate, the normalized frequency correcting value is corrected. Compared with a conventional method, the improved phase difference correction method taking regard of the power grid frequency change rate is more suitable for the frequency dynamic change condition, can achieve accurate and fast harmonic parameter measurement when the frequency fluctuation range is relatively large, the frequency change is uncertain even frequency collapse occurs, can accurately determine the change of the frequency change rate, and is beneficial to taking emergency control measures timely when the system frequency is abnormal to prevent grave electric system accidents such as large-scale power failure.

Description

technical field [0001] The invention belongs to the technical field of electric power harmonic analysis, in particular to an improved phase difference correction method considering the frequency change rate of a grid. Background technique [0002] The problem of power harmonics has attracted people's attention as early as the 1920s. With the rapid development of power electronics technology and the wide application of various nonlinear loads, harmonic pollution is becoming more and more serious. On-line measurement of power harmonics is an important technical means to control harmonic pollution. In recent years, the introduction and development of technologies such as micro-grid and new energy grid connection have provided a new application background for the accurate and rapid monitoring of power harmonic parameters. Fast Fourier transform (FFT) is one of the commonly used algorithms for power harmonic parameter measurement. Under synchronous sampling, the parameters of eac...

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Application Information

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IPC IPC(8): G01R23/16
CPCG01R23/16
Inventor 夏天伦林申力
Owner ZHEJIANG UNIV
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