DEVICE OF ELECTRIC CIRCUITS CURRENT PROTECTION AGAINST SINGLE-PHASE GROUND FAULTS (VERSIONS) Russian patent published in 2011 - IPC H02H3/16 G01R31/08 

FIELD: electricity.

SUBSTANCE: device of electric circuits current protection against single-phase ground faults comprises a zero sequence current sensor on each line and a relay unit of a protection block with the specified setpoint for actuation, besides, it is equipped with a functional module to calculate incompleteness of a ground fault, the first and second inlets of which are connected to a measurement voltage transformer, a protection block of each line additionally comprises a module of automatic adaptive correction of protection actuation setpoint current, to the first inlet of which a signal arrives about the setpoint current, its second inlet is connected to an outlet of the functional module to calculate an index of ground fault incompleteness, and the outlet of the module of automatic adaptive correction of protection actuation setpoint current is connected to the second inlet of the relay element of the protection block, the first inlet of which is connected with the sensor of zero sequence current. The second version of the proposed device - the protection block of each line additionally comprises a module of automatic adaptive correction of a signal value on a controlled zero sequence current of a line, the first inlet of which is connected to the zero sequence current sensor, its second inlet is connected to the outlet of the functional module to calculate incompleteness of ground fault, the outlet of the module of automatic adaptive correction of the protection actuation setpoint current is connected to the first inlet of the relay element of the protection block, and a signal arrives to its second inlet on the specified setpoint current.

EFFECT: provision of serviceability of current protection against single-phase ground faults in circuits with an insulated or resistive-grounded neutral line in case of faults via a transition resistance due to automatic adaptation of a protection to this ground fault mode.

2 cl, 2 dwg