Abstract: The present invention discloses a method for sectioning a medium-voltage distribution electric line evidencing a disturbance, wherein said method comprises the stages of: (a) evaluating a current in a medium-voltage line with a detection coil; (b) converting the intensity generated by said current by the detection coil in a potential difference, further transferring the information to a microprocessor; (c) analyzing the profile of the wave generated by the current by an algorithm to analyze harmonic levels by Fourier Series, and (d) determining the behavior or the section switch from the result obtained in (c).