Protections and automations are basic devices, that ensure maintaining normal operation on the electric power grid, and ward off its faults. Today’s protections with high computing capacity guarantee a wide range of set parameters and measurement methods. These parameters and measurement can be modified while operating. That allows creating one of the main conditions of live line working: the special operating mode. The increased sensitivity and the lack of time delay is needed to ensure the safety of the live line worker but it often causes false trips. Faults may cause this form other parts of the grid, or the asymmetry of the network.
Disconnections, during live line working, that interrupt consumers, decreases the quality of electricity supply. In my thesis, I examine the shaping, the operation and the protection of middle voltage networks, and the way these effects on the special operating mode. My goal is to propose changing on the special operating mode in order to avoid false trips.