Table 1: The simulation results of a single frequency voltage flicker signal by using two methods.

          Amplitude
        measurement		              Frequency
           measurement
Relative amplitude Error
(%)		 Frequency
(Hz)		 Error
(%)
Wavelet method 0.100692 0.692 8.995 0.0556
improved HHT 0.099985 0.015    8.9951 0.054