A Method for Estimating Harmonic Parameters Using Multi-time Scale Incomplete S-Transform

Abstract

The invention discloses a method for estimating harmonic parameters through multi-time-scale incomplete S transformation, comprising three function modules, namely, a time scale determination module (1), an incomplete S transformation calculation module (2), and a harmonic parameter estimation module (3). The time scale determination module (1) determines the calculated data sampling ratio of each frequency point of interest according to frequency ratio rules. When the point number of to-be-sampled data reaches a set value, the to-be-sampled data is output to the incomplete S transformation calculation module (2) to carry out incomplete S transformation calculation on the frequency point. The harmonic parameter estimation module (3) estimates the instantaneous amplitude, phase, frequency and other parameters of harmonic according to a complex vector obtained by the incomplete S transformation calculation module (2). A new way is provided for real-time analysis of frequency components of wide-frequency-domain signals.

Description

technical field [0001] The invention relates to the field of harmonic parameter estimation, in particular to a method for estimating harmonic parameters by using multi-time scale incomplete S transformation. Background technique [0002] With the continuous development of modern power systems and the continuous upgrading of industrial technologies such as microgrids, electrified railways, and smelting, their operating conditions are becoming increasingly complex and contain large-scale nonlinear power devices, causing a large number of non-stationary and complex harmonics in the wide frequency range to penetrate into the public grid, resulting in Harms such as system resonance, equipment aging, and misoperation of protection devices, it is necessary to control complex harmonics, and accurate estimation of its parameters is the premise of governance. [0003] Parameters such as amplitude, frequency, and phase of complex harmonics are time-varying. The traditional Fourier anal...

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Problems solved by technology

However, for the estimation of complex harmonic parameters, the incomplete S-transform still needs to solve the problems of frequency point detection, long transition time, elimination of end effects, and real-time tracking of frequency division.

[0004] The present invention applies the incomplete S transform to the real-time and accurate estimation of complex harmonic parameters, adopts different time scales for the frequency points of interest, ensures the real-time tracking and estimation accuracy of each frequency component, and overcomes the inability of the traditional Fourier transform method to non-stationary signals The limitations of accurate analysis, and at the same time solve the problems of common time-frequency analysis methods, such as large amount of calculation and difficulty in real-time application

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