1.Faculty of Electric Power Engineering, Kunming University of Science and Technology, Kunming 650500, China;2.Maintenance & Test Center of CSG EHV Transmission Company, Guangzhou 510663, China;3.Dali Bureau of CSG EHV Transmission Company, Dali 671000, China

The fault signal in grounding electrode lines is weak and well-hidden, making detection and fault location very difficult. On this basis, a single-ended location method for grounding electrode lines is proposed based on broadband excitation injection and short-time matrix pencil method (STMPM). Firstly, the Gaussian signal excitation with an oscillatory decaying characteristic is injected into the grounding electrode line in differential mode, ensuring that the injected excitation does not leak into the DC system side through the neutral bus and minimizing the waveform distortion to the greatest extent during the propagation of the signal along the grounding electrode line, thereby improving the detection efficiency of fault traveling waves. Secondly, sliding short-time windows are used to perform singular value decomposition (SVD) on the fault traveling waves. The eigenvalues obtained from the decomposition are used to distinguish the interference signals and fault signals, effectively amplifying the weak fault signals while suppressing the interference signals. Finally, the damping factor of the fault traveling wave within the short-time window is determined, a one-to-one mapping relationship between the zero-crossing moment of the damping factor and the arrival time of the fault traveling wave is established, and the fault distance is then determined. Extensive simulations show that the location method can effectively detect fault traveling waves and achieve high fault-location accuracy.

This work is supported by National Natural Science Foundation of China (No. 52167011).