The ongoing transformation of electrical power systems highlights the weaknesses of the protection schemes of traditional devices because they are designed and configured according to traditional characteristics of the system. Therefore

this work proposes a new methodology to study the fault-generated high frequency transient signals in transmission lines through multiresolution analysis. The high frequency components are determined by a new digital filtering technique based on mathematical morphology theory and a spectral energy index. Consequently

wide spectra of signals in the time-frequency domain are obtained. The performance of this method is verified on an electrical power system modeled in ATP-Draw

where simulation and test signals are developed for different locations

fault resistances

inception angles

high frequency noises

sampling frequencies

types of faults

and shapes of the structuring element. The results show the characteristics of the fault such as the traveling wave frequency

location

and starting time.