Power quality detecting based on fast lifting wavelet transform

This paper advances a novel method for power quality detection by using fast lifting wavelet transform and utilizing the reconstructed signal to compensate for the harmonics. After the disturbed signal is decomposed to many sub-bands in frequency domain, the disturbing time and level can be identified and the disturbed signal can be compensated by the reconstructed signal. In this paper, the theory of fast lifting wavelet transform is given and the lifting wavelet of Daubechies(9/7) is applied to detect voltage sag, transient disturb and harmonics. Simulations validate that the method display a good detecting performance in both time and frequency domain and can depict the strange characteristics of the signal. Compared to traditional wavelet transform, the lifting wavelet transform depresses calculation complexity, effectively reducing calculation time and no additional memory is required, thus it is more practicability.