A Novel DC Transmission System Fault Location Technique for Offshore Renewable Energy Harvesting

Advances in renewable energy recourses technologies have paved the way for increased utilization of DC grids in modern power systems. In particular, high voltage DC (HVDC) transmission cables are used to harvest offshore energy. Since failure diagnosis and repair of the buried offshore cables under the sea bed involve quite laborious tasks, accurate fault location is of vital importance. This paper proposes a novel fault location method based on the synchronized measurement of conductors and sheaths currents in each terminal without requiring the voltage signal. Unlike the traveling-wave-based methods, the proposed method is developed for multi-terminal HVDC systems without requiring any high precision measurement infrastructure. The proposed method can be implemented for different system topologies as well as fault resistance and fault distance. The fault location method can provide accurate results even if 10 ms time window samples are imported into the proposed algorithm. In addition, accuracy of the fault location using the proposed method is not affected significantly by noisy condition. Different test systems have been simulated to evaluate performance of the proposed method in various scenarios. Obtained results confirm that the proposed practical method can provide the accurate fault location for all different scenarios and conditions.