DEVICE FOR CURRENT PROTECTION OF NEGATIVE SEQUENCE AGAINST SINGLE-PHASE EARTH FAULTS OF ELECTRIC NETWORKS OF MEDIUM VOLTAGE CLASS Russian patent published in 2024 - IPC H02H3/16 

FIELD: electric power industry.

SUBSTANCE: invention relates to electric power industry and can be used in electric networks of medium voltage class 6-35 kV, operating with isolated neutral, at occurrence of stable single-phase earth faults (SSEF), short-term single-phase earth faults (ShSEF), arc single-phase earth faults (ASEF), arc intermittent single-phase earth faults (AISEF). Technical result is achieved due to the use of negative sequence current in the structure of the unit, the operation of which, in contrast to the standard algorithms based on the measurement of the zero sequence current, is based on the measurement of the negative sequence current, which appears only in the damaged phase, which in turn makes it possible to implement protection against short-term, arc, alternating arc and stable single-phase earth faults.

EFFECT: higher selectivity and stability of protection of electric networks of medium voltage 6-35 kV.

1 cl, 1 dwg