Fault location on multi-terminal DC systems using synchronized current measurements

Multi-terminal dc transmission systems are suitable substitutes for their ac counterparts, once the associated costs are justified. This paper proposes a new traveling wave-based fault location method for multi-terminal dc (MTDC) systems. In doing so, the fault section and its included lines are specified using a straightforward algorithm. Then, an evaluation index is developed to determine the faulted line amongst all included ones in the fault section. Finally, a system of linear equations taking into account the fault inception time, the fault location and the first arrival times at different detector locations are constructed and solved. The method merely needs the first current surge arrival times, thus eliminating the practical difficulties in relation with identifying other traveling wave features. Besides, the fault is easily located despite the complexity of the network topology, i.e., the number of its meshes and radial lines. To examine the effectiveness of the proposed method, a large number of simulation studies are conducted on a complicated MTDC system. Obtained results verify the high accuracy, noise immunity and fault impedance robustness of the proposed method.