DIFFERENTIAL RELAY Russian patent published in 2004 - IPC

FIELD: electrical engineering, applicable in protective devices against short-circuit currents. SUBSTANCE: the differential relay has an intermediate current transformer, rectifier unit, two threshold units, clock pulse generator, three AND-gates, two pulse counters, two filters-averagers, algebraic adder, three delay units, two OR-gates, two pulse counters, one-shot multivibrator, RS flip-flop and two short-pulse shapers. EFFECT: enhanced precision since a protection against interference is provided in the relay and the influence of current frequency variations is reduced. 2 dwg