Permanent fault identification and location scheme for MTDC grid based on equivalent impedance phase characteristics and distributed parameter line

To ensure the reliability of the MTDC grid's recovery system during the reclosing stage, identifying permanent faults is crucial. Therefore, a permanent fault identification and location scheme is proposed based on equivalent impedance phase characteristics and distributed parameter lines. The equivalent impedances with distributed parameter lines in permanent and temporary faults are investigated. The proposed scheme for identifying a permanent fault is based on the phase characteristics of the equivalent impedances. The proposed scheme for permanent fault location is achieved by solving the fault location equation considering distributed parameter lines to determine the fault distance. Simulation results indicate that the proposed scheme is suitable for long-distance DC transmission lines and is less affected by the sampling rate, fault locations, fault resistance, and noise. The proposed scheme improves the reliability and sensitivity of permanent fault detection.