FIELD: electricity.
SUBSTANCE: invention deals with techniques for detection of ground faults in electric mains. Essence of the invention: the method includes detection of ground fault based on measured three-phase currents iA, iB and iC and receipt of time instant t corresponding to the instant of the very detection of ground fault; determination whether this ground fault is single-phase ground fault or two-phase ground fault on the basis of three increment phase currents ΔiA, ΔiB and ΔiC at time instant t; and if single-phase ground fault is detected it is found out whether this ground fault is located upstream the line or downstream the line on the basis of amplitude of increment phase current of the closed phase.
EFFECT: improved accuracy for detection of ground fault spot, necessity of voltage sensor installation is eliminated.
15 cl, 6 dwg
