DEVICE FOR DIFFERENTIAL PROTECTION OF POWER TRANSFORMER Russian patent published in 2013 - IPC H02H7/45 

FIELD: electricity.

SUBSTANCE: device includes current sensors that consist of a secondary winding and a core from non-magnetic material, smoothing filters, a signal converter, a differential signal shaping unit, the first shaper of actual value of input signal, an actuation set point shaping unit, the first braking chain that includes a signal delay unit, an adder and the second shaper of actual value of input signal, the second braking chain that includes a braking signal shaping unit and the third shaper of actual value of input signal, the first and the second locking member, as well as a responding member that includes a comparator and a logic unit.

EFFECT: improving quick action at external short circuits, and increasing sensitivity to turn-to-turn short-circuits in a power transformer in maximum loading modes.

9 dwg