Harmonic analysis method of power quality harmonic analyzer

Abstract

The invention discloses a harmonic analysis method of a power quality harmonic analyzer. The harmonic analysis method of the power quality harmonic analyzer is realized through improvement based on a quasi-synchronous DFT. The harmonic analysis method of the power quality harmonic analyzer comprises the steps that an electrical signal X on which harmonic analysis needs to be conducted is sampled in a power grid, and data of W+2 sampling points are sampled at equal intervals; the position for frequency domain sampling is changed according to the drifting Mu a signal frequency, when the harmonic analysis is conducted by means of the quasi-synchronous DFT, namely the position for the frequency domain sampling is Mu2pi / N. According to the harmonic analysis method of the power quality harmonic analyzer, after the amplitude and the initial phase angle of each harmonic wave of the electric signal X are calculated, the percentage and the phase angle difference between the amplitude value Pk of a higher harmonic and the amplitude value of a fundamental harmonic P1 of a voltage signal V and the percentage and the phase angle difference between the amplitude value Pk of a higher harmonic and the amplitude value of a fundamental harmonic P1 of a current signal I are calculated respectively, output and displayed.

Description

[0001] This application is a divisional application, the application number of the original application: 201110322629.4, the name of the invention and creation: a harmonic analysis method for a power quality harmonic analyzer, and the application date: 2011-10-21. technical field [0002] The invention relates to the technical field of power quality harmonic analysis, in particular to a high-precision harmonic analysis method. Background technique [0003] Harmonic analysis technology is widely used in many fields such as power quality monitoring, electronic product production inspection, electrical equipment monitoring, etc. It is an important technical means for power grid monitoring, quality inspection, and equipment monitoring. [0004] In the power supply grid, the generation of harmonics is mainly caused by large-capacity power equipment, power rectifier or converter equipment, and other nonlinear loads. In recent years, with the rapid development of power electronics ...

AI Technical Summary

Problems solved by technology

[0008] In engineering applications, harmonic analysis always performs limited sampling and it is difficult to achieve strict synchronous sampling

In this way, when quasi-synchronous DFT is used for harmonic analysis, there will be long-range leakage due to the truncation effect and short-range leakage due to the fence effect, making the analysis results inaccurate and even unreliable

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