Research on Local Mean Decomposition Algorithms in Harmonic and Voltage Flicker Detection of Microgrid

Abstract

In allusion to harmonic and voltage flicker in microgrid, the local mean decomposition algorithm is adopted to analyze harmonic and voltage flicker in power system. Complex original signals can be decomposed into a number of PF (product function) component, each layer of PF is composed of the envelope signal and frequency modulation function, which contains all the instantaneous amplitude and instantaneous frequency information. Further combinations can get the original signal time frequency distribution. Using the LMD to detect the harmonic signal and the multiple frequency voltage flicker signal in microgrid, The simulation results show that this Algorithm can adaptively decompose the signal and highlight the local characteristics of PF data, the method can be accurate analysis of multi frequency harmonic distortion signal, interharmonic signal and multiple frequency voltage flicker signal. Simulation waveform is not only influenced by "end effect" of small effect, and the instantaneous frequency is always positive. According to the actual analysis of a transformer with multi-frequency signal power in a microgrid system, using LMD algorithm and HHT algorithm, The result further prove the correctness of the proposed method, which provides the theoretical fundamental in a new way for the electrical energy detection in power system.

Keywords

• Local mean decomposition
• Harmonic
• Voltage flicker
• Power quality detection
• Microgrid.