FIELD: electrical engineering.
SUBSTANCE: invention relates to the field of electrical engineering. According to the invention, the values of the active resistances of three ballast elements are determined, which are connected to the three-phase switch of the backup cell, connected to a star, the neutral of which is connected through the active resistance to the ground loop of the switchgear. The zero sequence current relay protection settings of all connections are formed, which generate a signal to disconnect the connection with a single-phase ground fault after the backup cell switch is turned on when a zero sequence voltage signal appears on the busbar section from the voltage transformer through the relay. The relay has a time delay, which allows to turn off the damaged connection after a specified time after the occurrence of the SEF.
EFFECT: increasing the reliability of determining the connection with a single-phase earth fault (SEF) in electrical networks of 6-35 kV with an isolated neutral.
1 cl, 3 dwg, 3 tbl
