Hilbert-Huang transform applied to voltage flicker

ZHAO Ying-nan1， CHEN Long-dao1， WEN Hao-xiang1， ZHANG Fan2
（1. College of Electrical Engineering， Zhejiang University， Hangzhou 310027， China；
2. Jilin Electric Power Survey & Design Institute， Changchun 130022， China）

Abstract： Voltage flicker is one of the most important factors of electric power quality.Aiming to calculate flicker level，the application of Hilbert-Huang transform（HHT）to voltage fluctuation testing was investigated. HHT was applied to voltage envelope to get time-varying information.Then instantaneous flicker sensation was derived from product of instantaneous voltage amplitude and its weighting coefficient in corresponding frequency. The short-time flicker severity was obtained after statistical analysis. A simulation was made to analyze voltage signal with 10 Hz and 20 Hz. 100 flicker outputs can be obtained per second. After statistical analysis，the error between experimental result and theoretical result is only 3.863%，which can meet the requirement of IEC. The result indicates that，compared with other approaches such as method based on IEC and FFT，HHT is more capable in processing non-stationary signal，and can provide quick and effective results while presenting real-time information of voltage and frequency.
Key words： power quality； voltage flicker； Hilbert-Huang transform（HHT）； time-frequency analysis； instantaneous flicker sensation