Ultra-high-voltage direct-current transmission line single-end protective method

The invention relates to an ultra-high-voltage direct-current transmission line single-end protective method, and belongs to the technical field of high-voltage direct-current transmission system replay protection. The method includes the steps that firstly, a data acquisition device acquires the fault current data in a time window of 5 ms after a fault current travelling wave head wave head reaches, and a 1 model component is solved; then 1 model current which operates normally before fault is subtracted from a 1 model component current signal, the fault current variable quantity is obtained, summation operation is conducted on the fault current variable quantity, and whether the signal comes from the exterior of a rectification side region or from the exterior of a circuit or the exterior of a contravariant side region is judged according to the summation operation; Hilbert-Huang transform is conducted on the fault current signal from the exterior of the circuit or the exterior of the contravariant side region, the instantaneous frequency maximum value of the signal is obtained, the obtained instantaneous frequency maximum value is compared with the preset threshold value to judge whether the circuit or the exterior of the contravariant side region breaks down. By means of the ultra-high-voltage direct-current transmission line single-end protective method, the full-line protection of an ultra-high-voltage direct-current transmission line can be achieved, and the good speed can be guaranteed.