Relay protection is a set of devices designed for quick, automatic (in case of damage) detection and separation of damaged elements of this electric power system from the electric power system in emergency situations in order to ensure the normal operation of the entire system. The actions of relay protection facilities are organized according to the principle of continuous assessment of the technical condition of individual controlled elements of electric power systems. Relay protection (RP) continuously monitors the state of all elements of the electric power system and reacts to the occurrence of damage and abnormal modes. In the event of damage, the RP must identify the damaged area and disconnect it from the EPS by acting on special power switches designed to open the damage currents (short circuit).