Compression of Power Quality Data Based on Improved DCT Transform

Abstract

Compression is the preprocessing work before power quality event data transmission and analysis. In this paper segmented discrete cosine transform (DCT) was used for power quality signal compression. For transient power quality event, such as short duration voltage variation, wavelet transform was used to detect the singularity of the signal firstly. Then the signal was divided into segments by singularities and DCT was performed following. The simulation results show that for stable power quality data, the compression effect of DCT is better than that of wavelet transform. And for short duration voltage variation signal, the compression effect of segmented DCT is better than that of direct DCT. Finally the experiment result was presented to prove the effection of above method.

Keywords

• Power quality
• Short duration voltage variation
• Data compression
• Wavelet transform
• Segmented DCT.