Optimized Secondary Arc Mitigation in Hybrid AC/DC Transmission Lines

Hybrid AC/DC transmission lines are an efficient alternative to conventional AC/AC systems. However, protection design poses unique challenges that motivate further study. The present paper introduces a genetic optimization framework targeting critical performance metrics: secondary arc current (SAC) suppression, secondary arc extinction time (SET) reduction, and transient recovery voltage (TRV) stabilization. Harnessing synchronized PSCAD-MATLAB simulations based on the Nondominated Sorting Genetic Algorithm II (NSGA-II), shunt reactor parameters are optimized for both baseline (AC/AC) and hybrid configurations. Optimized neutral reactors reduce unnecessary compensation by up to 85% compared to analytical designs that ignore inter-circuit coupling. Outperforming the conventional AC/AC system, the best-performing hybrid configuration requires 22% less reactor capacity and achieves up to a 96% size reduction relative to analytically derived parameters. These results demonstrate that single-phase auto-reclosing (SPAR) in hybrid lines can ensure both protection reliability and economic efficiency when supported by tuned shunt compensation.