Compression of 2-D representation of power quality event data
Song Bao-ming · Journal of Zhejiang University(Engineering Science) · 2008
Embedded zerotree wavelet(EZW) algorithm used in image compression was applied to compress the 2-D representation of power quality event data in order to handle mass data from power quality monitoring.1-D power quality event data were transformed to be 2-D after event data were cut off and reconstructed according to an integer multiple of data period;2-D wavelet multiresolution analysis was performed to decompose the 2-D data to an array of wavelet coefficients;and EZW was applied to complete compression.2-D representation allows EZW to be directly applied;so it is unnecessary to change EZW to adapt the original 1-D data.Simulation and test results show that this method has high compressibility,high speed,and invariable characters.When seven-stage quantization was adopted,67.5% data storage space was saved and the characters of power quality event data were kept unchanged.