Arc Extinction Instant Identification Method for Single-Pole Grounding Faults in VSC-HVDC Transmission Systems

Conventional auto-reclosing schemes, relying on fixed delays, exhibit operational blindness that risks secondary system impacts or prolonged outages. This study addresses these limitations through adaptive reclosing technology. The variation characteristics of the fault-pole voltage before and after arc extinction are first analyzed in this study. Fourier decomposition of recovery voltage revealed frequency-specific variations, leading to the definition of a 50 Hz incremental percentage parameter (H₁) as the arc extinction identifier. Adaptive reclosing logic was developed by monitoring H₁ against adaptive thresholds. Implemented in a four-terminal MMC-HVDC PSCAD/EMTDC model simulating DC-side faults, The simulation results demonstrate that this arc extinction time identification method achieves rapid recognition and can accurately capture the moment of fault arc extinction within several milliseconds. The identification error of arc extinction time under various fault conditions is less than 10 ms. The adaptive reclosing strategy, which accounts for arc extinction time identification, enables reliable recognition of the arc extinction moment, effectively shortens the reclosing process, and enhances system reliability.