DEVICE FOR PROTECTING OF GENERATOR STATOR WINDING AGAINST FAULT TO GROUND Russian patent published in 2015 - IPC H02H7/06 

FIELD: electricity.

SUBSTANCE: for implementation of protection the control current source of non-industrial frequency is connected to the open triangle of the voltage transformer via the filter which has small resistance at the control current frequency and large resistance at the industrial frequency. It is achieved by that in series with a current-limiting element which in the known device appears to be a throttle with the straight-line volt-ampere characteristic, the capacitor is connected. Due to this the requirements of providing of control current, sufficient for reliable measurement, and necessary limitation of industrial frequency current are agreed. The protection actuator is connected to the secondary winding of the measuring voltage transformer connected in open triangle. The selective body which provides the function of protection selectivity, is connected to the zero-sequence current filter which is installed on generator terminals. Outputs of the actuator and selective body are connected to the inputs of AND logical element.

EFFECT: improved selectivity of protection.

1 dwg