In this article the analysis of the impact of electromechanical transients caused by the aperture of a line in a unbalanced Active Distribution System using the methodology of modeling and simulation in PowerFactory DIgSILENT software is presented. The results allow to determine the voltage limits coupled to the electrical system and the considerations to be taken into account for the settlement of the event. The article is organized as follows, presents an introduction to the topic of electromechanical transient and Active Distribution System, followed by the description of the case study and simulations, then the analysis and interpretation of the results is presented and finally the conclusions and recommendations.