The invention belongs to the field of power
system relay protection, and particularly relates to a direct-current
transmission line pilot protection method and application thereof, and the method comprises the steps: collecting and filtering
voltage and current, and calculating the comprehensive
admittance of a single-pole line if the single-pole line is the single-pole line; if the line is a bipolar line, calculating differential current of a positive line and a negative line and an integral value of the differential current in a
current time window for fault pole selection, and calculating
voltage common modulus and
voltage differential modulus of a rectification side and an inversion side to calculate common-mode comprehensive
admittance and differential-mode comprehensive
admittance; fault area judgment is carried out by using a criterion based on unipolar line comprehensive admittance; or, if the pole selection result is single-pole grounding, the criterion based on common-mode comprehensive admittance is adopted for fault area judgment, and if the pole selection result is inter-pole
short circuit, the criterion based on differential-mode comprehensive admittance is adopted for fault area judgment. According to the method, the criterion is simple, the transition resistance resistance is high, no line parameter is needed, and compared with a traditional current
differential protection non-locking process, the action speed of line
backup protection can be effectively improved.