The energy wasted due to faults or interruption in servicing consumers, causing a lack of reliability of power system in the electric market. Therefore, locating and diagnosing faults in power distribution networks enhance system reliability and prevent potential risks for people and system. Faults in 20-kv power distribution network are associated with the arc, due to low voltage conductors and poor connections with the ground or grounded object. Such arc creates large impedance so arc faults are known as high impedance faults that make it difficult to detect and locate. To calculate the arc characteristics and their impact on the waveforms , voltage and electric current have been simulated in the laboratory and practical results have been utilized in EMTP program to model faults. Unlike such results mentioned in some paper, the model precisely shows that the arcing fault doesn’t include pure ohm or Induction properties, but its nature is same as a capacitor. Then comparing the frequency content of such model with the real arc is carried out through wavelet transform, to examine the validity of the fault model. This model can be used to design and test protective relays, as well as design of fault detection and location algorithms
