Protection Scheme Based on Estimated Traveling Wave Arrival Times for Renewable Energy Transmission Line

Owing to the weak grid characteristics of renewable energy resources, conventional protection methods based on power frequency components are inadequate in ensuring the safety of the power grid. To address this issue, this paper first analyzes the refraction and reflection process of traveling waves that occur at different fault locations. Then, the time of the third voltage traveling wave arriving at the relay location can be estimated, which is compared to the actual arrival time to differentiate the internal faults and external faults. To further address the challenge of accurately identifying near-end and remote-end faults, an auxiliary criterion is proposed. On this basis, this paper developed a single-ended protection scheme for renewable energy transmission line. Finally, based on PSCAD/EMTDC simulation platform, the protection scheme is verified. The obtained results provide compelling evidence that the proposed scheme is less affected by fault resistances, and the operation time of the protection scheme is no more than 3 ms.