DEVICE FOR SELECTIVE PROTECTION AGAINST GROUND FAULTS IN STATOR WINDING OF GENERATORS OPERATING IN ENLARGED UNIT Russian patent published in 2006 - IPC H02H7/06 H02H3/16 

FIELD: relay protection.

SUBSTANCE: the device has a reference current source series-connected to an are extinction reactor, zero phase-sequence current filter installed on the side of generator leadouts, starter whose first input is connected to the secondary winding of the arc extinction reactor, and the second input is connected to the measuring winding of the reference current source, logical unit, whose first input is connected to the starter output, selective component, whose output is connected to the second input of the logical unit, current transformer series-connected to the arc extinction reactor on the side of the generator neutral, low-frequency filter, whose input is connected to the output of the zero phase-frequency current filter and to the secondary winding of the current transformer, and the output is connected to the selector input, the zero phase-frequency current filter and the current transformer are connected according to the differential circuit.

EFFECT: provided selectivity of protection both at stable ground faults and at alternate arc faults.

1 dwg