Single-ended Protection Scheme for MMC-HVDC System Based on Transient First-wave of Voltage

Since the fault characteristics of multi-terminal HVDC grid are far more complicated, it is essential to put forward a fast and reliable protection method. For the Zhangbei ±500 kV MMC-MTDC grid, this paper proposes a novel single-ended protection scheme. In this scheme, the singularities of voltage transient signal are used to detect faults, and the amplitude-to-time ratio of the first-wave of transient voltage is used to distinguish the fault section, while the difference of voltage amplitude is utilized to discriminate the fault pole. At last, the simulation model of Zhangbei ±500 kV MMC-MTDC grid is built by using PSCAD/EMTDC software, and the effectiveness of the proposed scheme is verified under various simulated fault scenarios.