Adjacent harmonic and inter-harmonic separation and measurement method under IEC (international electrotechnical commission) framework

Abstract

The invention discloses an adjacent harmonic and inter-harmonic separation and measurement method under an IEC (international electrotechnical commission) framework. The method includes the following steps: firstly, performing discrete sampling on a power grid signal; secondly, performing ten-cycle Hanning window addition DFT / FFT (discrete Fourier transform / fast Fourier transform) spectral transformation on a sampling value according to IEC standards so as to obtain a spectrum; thirdly, multiplying the spectrum by rotary phase factors to obtain a new spectrum; fourthly, solving a vector sum of neighboring spectral lines of the new spectrum so as to offset sidelobe interference of rest components on the new spectrum, and solving corresponding frequency, a frequency deviation value and amplitude phase via a spectral line phase cancellation interpolation method; fifthly, rejecting spectrum leakage values of a fundamental component and the rest components at spectral line attention positions on a frequency domain; sixthly, solving a harmonic spectrum value to obtain parameters of h subharmonics, and solving parameters of inter-harmonics adjacent to the h subharmonics. By the method, the problem that the parameters of the two adjacent harmonics and inter-harmonics cannot be measured accurately during limited data asynchronous sampling is solved.

Description

technical field [0001] The invention relates to a method for measuring harmonic separation between adjacent harmonics under the framework of IEC, and belongs to the field of power quality analysis. Background technique [0002] The International Electrotechnical Commission (IEC) stipulates the use of algorithms based on DFT / FFT spectrum analysis for power harmonic and interharmonic analysis, and stipulates that the length of the analysis window is 10 fundamental frequency cycles, and requires a rectangular window for synchronous sampling , it is recommended to add a Hanning window when sampling asynchronously. The defect of the IEC method is that it does not give a specific algorithm for adding the Hanning window during asynchronous sampling, and cannot perform accurate measurement of harmonic and interharmonic parameters. When the harmonic and inter-harmonic frequencies are relatively close to each other, or even less than one frequency resolution apart, the harmonic spect...

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Problems solved by technology

[0005] The invention provides a method for measuring the separation of adjacent harmonics and inter-harmonics under the IEC framework, which solves the problem that the parameters of two adjacent harmonics and inter-harmonics cannot be accurately measured when limited asynchronous sampling data is available, especially for Under the high-frequency sampling rate, adjacent high-order harmonics and inter-harmonic parameters are separated and measured, and at the same time, it can suppress the sidelobe leakage interference of other components, realize accurate detection, and ensure real-time measurement requirements

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