Discrete wavelet transform applied to data compression of waveforms with harmonics and voltage flicker

The discrete wavelet transform is used to enhance data storage capability of power quality measurement instruments in monitoring waveforms with harmonics and voltage flicker. The compression approaches with multi-resolution analysis and reference waveform are compared. The results from spectrum analysis show high compression ratios while keeping low data distortion. The error levels between original and reconstructed waveforms are discussed. Field measured waveforms with harmonics and voltage flicker from arc furnace loads are used to show the goodness of the data compression techniques. While the multi-resolution analysis approach is suitable for voltage flicker, the reference waveform method is better for harmonics.