Voltage flicker detection algorithm based on improved HHT (Hilbert-Huang Transform)

Abstract

The invention discloses a voltage flicker detection algorithm based on improved HHT (Hilbert-Huang Transform). The voltage flicker detection algorithm comprises the following steps: 1) extracting voltage envelope signals from collected discrete voltage signals by using a Hilbert transform method; 2) in an empirical mode decomposition (EMD) 'screening' step, 'splitting' a new control point for three times of spline interpolation fitting of an envelope line by using a four-point interpolation subdivision algorithm, and optimizing the new control point by the method; and 3) decomposing the voltage envelope signals by using improved EMD so as to obtain a group of intrinsic mode functions (IMF), and extracting flicker amplitude values and flicker frequency parameters from the group of decomposed IMF by using the Hilbert transform method respectively. The voltage flicker detection algorithm disclosed by the invention effectively overcomes the problem that parameter detection errors are increased due to unsatisfactory IMF generated by EMD, thereby obtaining a parameter detection result with higher precision.

Description

technical field [0001] The invention relates to a voltage flicker detection algorithm based on an improved HHT, and belongs to the technical field of signal processing. Background technique [0002] The large number of distributed power sources in the power grid and the input of various nonlinear, impact and fluctuating loads have aggravated the voltage fluctuations in the power grid, and the frequent occurrence of voltage flicker in the power grid has seriously affected industrial production and social life. . Power supply and utilization companies hope to detect accurate voltage flicker parameters, so that they can install compensation equipment in a targeted manner to control voltage flicker, so as to improve power quality. [0003] In recent years, voltage fluctuation and flicker detection problems have gradually become research hotspots. IEC has given a detection principle block diagram for measuring flicker intensity values. Scholars have proposed a variety of short-t...

AI Technical Summary

Problems solved by technology

The atomic decomposition method detects the voltage flicker signal, and the accuracy of the detection parameters is high, but the calculation amount is large and the running time is long

The voltage flicker detection method combining Prony and Hilbert selects the algorithm based on Hilbert transform to detect the voltage fluctuation signal, and introduces the extended Prony algorithm to estimate the signal frequency parameters, but the anti-noise ability is not ideal

The Empirical Mode Decomposition (EMD) in the HHT voltage flicker detection method has modal aliasing and terminal flying wings, which makes the decomposed IMF components unsatisfactory and seriously affects the accuracy of flicker parameter detection.

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