Research on improved fault classification scheme during power swing

To ensure distance relay can measure the impedance and trip the fault phase selectively during power swing, it is necessary to study fault classification during power swing. The conventional sequence current and phase-to-phase impedance relay based fault classification scheme has been analyzed to mal-operate in some cases during power swing. In order to overcome the disadvantage, single-phase-to-ground impedance relay and phase-to-phase impedance relay and sequence voltage criterion based improved fault classification scheme is proposed in this paper. The results of ATP digital simulation and dynamic simulation tests indicate that proposed scheme has advantage with origin scheme particularly in fault classification under the condition of power swing.