The emergence of various transients prose’s in power distribution networks of various class types of tension have a probabilistic nature, discrete change and depend on several factors both certain and uncertain. Very often, these transients are asymmetric, and transformed into short circuits that have a significant impact on the functional safety of installed electrical equipment. It is necessary to define the relationship between symmetric and asymmetric transition modes in the distribution systems in order to establish their quantitative transfer to a short circuit, which, depending on their place of origin and flow rate, these are accompanied by short-circuit currents of different magnitudes, which are essential to the functional reliability of the installed equipment.