This paper is a brief introduction to discrete wavelet transform as digital signal-processing

technique and the application. The field of discrete wavelet transform (DWT) is an

amazingly recent one because itÌ s better than Fourier transform. This technique was used on

power system to partial discharge site location. Partial discharges are caused by various

defects such as voids, shield protrusions, contaminants, advanced stages of water tree, etc

and known the main cause of breakdown in insulation materials.