Direct current system line fault positioning method

The invention discloses a direct current system line fault positioning method. The method includes steps: firstly, deducing a voltage and current transient characteristic equation of lines with different fault types based on a VSC direct current system, and calculating a current differential initial value during the fault; performing fault discrimination by employing catastrophes of a positive electrode and a negative electrode in different fault types, and determining the fault type and the fault electrode after occurrence of the fault; then calculating a post-fault current and voltage characteristic equation, and calculating the transition resistance of a fault circuit; and finally deducing a fault positioning value by employing the current differential initial value during the fault, and realizing accuracy positioning of the line faults. According to the method, the fault positioning precision is high for a direct current system with high transition resistance and long distance, and the method can be appli