Double-Ended Traveling Wave-Based Method for Pole-to-Ground Fault Location on HVDC Transmission Lines
Electromagnetic transients, fault location, HVDC transmission lines, power systems, traveling waves.
This thesis proposes a double-ended method based on traveling waves (TWs) for locating pole-to-ground (PG) faults on high-voltage direct current (HVDC) transmission lines. PG faults are more likely and critical than pole-to-pole (PP) faults on HVDC lines. Hence, accurate PG fault location is important to quickly restore HVDC systems after unscheduled shutdowns. An analysis of the TWs launched by PG faults reveals that refracted TWs can be easily detected at both line ends using an amplitude- and polarity-based criterion. Based on this finding, a double-ended PG fault location method free of TW propagation velocity settings and data synchronization means is proposed. Simulations in the Rio Madeira HVDC system using the Alternative Transients Program (ATP) were carried out. The transmission line was implemented using the distributed parameter frequency-dependent JMarti model. Results show that the method is accurate, presenting errors smaller than 0.6 km (0.02% of the transmission line length). Also, the method is revealed to be immune to data synchronization misalignments, being robust to different fault resistances, noise levels, soil resistivities, and sampling frequencies. Finally, a comparative study shows that the method is more simple, accurate, and robust than the state-of-the-art TW-based fault location (TWFL) methods.