Locating Natural Frequency Faults in HVDC Transmission Systems Based on the Rotation-Invariant Technology Signal Parameter Estimation Algorithm and the Total Least Squares Method

After a fault occurs in a high-voltage direct current transmission (HVDC) line, the natural frequency of the fault wave contains a wealth of transient information. The mathematical relationship between the main component of the natural frequency and the fault point can be determined and used for rapid and high-precision fault locations. To accurately extract the natural frequency of a fault and improve the positioning accuracy, a single-ended ranging scheme for extracting the natural frequency of an HVDC transient traveling wave based on the rotation-invariant technology signal parameter estimation algorithm (TLS-ESPRIT) and the total least square method is proposed for the first time. The simulation platform is used to build a dual-ended unipolar and bipolar DC transmission system model, and the scheme is simulated and verified for metallic grounding at different locations and with different transition resistances at the same location. The verification experiment was carried out on the recorded wave data of the "3.21" grounding fault of the Tianguang (Tianshengqiao-Guangdong) DC line. The results showed that the algorithm can rapidly locate the ground fault in the HVDC line and provide high ranging accuracy and good practicality.