Symmetric Excitation Injection and STMPM Based Fault Location in HVDC Grounding Electrode Lines

Fault detection and precise localization in High-Voltage Direct Current grounding electrode lines are extremely challenging due to the weak and highly concealed nature of fault information. To address this, a novel single-ended ranging algorithm based on broadband excitation injection and the Short-Time Matrix Pencil Method is proposed. Firstly, a dual-pulse square wave excitation with \even-symmetry characteristics\ is injected into the electrode line in differential mode. This approach ensures the injection does not interfere with the DC system via the neutral bus while minimizing waveform distortion during propagation. Secondly, a sliding short-time window is employed to perform Singular Value Decomposition on the fault-induced traveling waves. By analyzing the eigenvalue characteristics from the decomposition, interference signals are effectively distinguished from fault signals, thereby amplifying weak fault signatures and suppressing noise. The key innovation lies in establishing a \u200bone-to-one mapping relationship between the zero-crossing moment of the attenuation factor and the arrival time of the fault traveling wavefront, enabling highly accurate fault distance calculation by calibrating this specific point. Extensive simulation results and field tests demonstrate that this algorithm reliably detects fault traveling waves and achieves high-precision fault localization, significantly outperforming conventional methods.