HHT based on the LS-SVM and its application in the voltage flicker and harmonic detection of microgrid

Microgrid contains many distributed resources (DR), such as photovoltaic, wind power, and these DR which have the characteristics of random, volatility and intermittent, will cause voltage fluctuation and flicker, therefore, harmonic pollution will be produced from power electronic devices in DR. Hilbert-Huang Transform (HHT) can distill these disturbing signals automatically and time-frequency spectrum can be obtained. However, in the application of this method there are serious end effects that mixed mode phenomenon will appear, affecting the detecting results. In order to suppress the end effects, a novel HHT based on Least Squares Support Vector Machine (LS-SVM) is applied to analyze voltage flicker and harmonic in microgrid. The results show that the improved HHT method is effective to control the end effects and the time, frequency and amplitude of disturbing signal will be detected quickly and effectively.