Analysis on measuring performance of three Flicker Detecting Methods

Voltage fluctuation and flicker is an important aspect of power quality. The core of flicker analysis is to track the envelope of voltage signals and then calculate the short-term flicker severity P_st, which is the premise of flicker source location. This paper firstly derives the formulas of extracting flicker envelope of signals containing harmonics using Teager energy operator and Hilbert transform. Then the measuring performance of Teager energy operator, Hilbert transform and square demodulation of flicker with one frequency, multi-frequencies and with harmonics are analyzed. After extracting the flicker envelope, the flicker frequency and amplitude error, and short-term flicker severity P_st error are calculated. Besides the relationships between amplitude error and frequency, P_st error and frequency with respect to these three methods are illustrated respectively. At last it is proved that Hilbert transform has the highest accuracy and stability than TEO and square demodulation with the increase of frequency.