Protection of the power system and its large and small equipment is one of the most important tasks that must be done in the best way to ensure the stability, sustainability and constant activity of the system. This issue is especially important in the electric energy distribution system, which is the most extensive part in a large power system, Because, on the one hand, most errors occur in the distribution network, and on the other hand, its close relationship with electric energy consumers increases the necessity of its correct and continuous function. The correct function of the distribution network depends not only on its design accuracy, but also depends on the correct regulation of protective equipment, because the correct and timely regulation makes the faults in the distribution network quickly and accurately resolved and the quality of power supply improves.