In view of the existence of the problem of late splitting devices action of multi-channel receiving section and asynchronism

by drawing on the experience of Southern Power Grid

the discrimination cycle is shortened by adopting the time-domain simulation method. Improvement measures to build intertripping residual channels are proposed which are helpful to grid stability recovery after splitting. The factors of under-frequency load shedding

over-frequency generator tripping and electromagnetic loop network breaking may cause out-of-step oscillation center migration. The influences of splitting device action time on the third line of defense measures for sending-end and receiving-end grids are studied.