In power systems with high renewable energy penetration, rapid and accurate separation of positive- and negative-sequence voltage components under asymmetric faults is crucial for converter fault ride-through capability and system stability. However, dynamic response characteristics (e.g., separation time) of sequence separation remain insufficiently explored. As a widely adopted solution, the Decoupled Double Synchronous Reference Frame PLL (DDSRF-PLL) suffers from high modeling complexity, hindering comprehensive parameter design. To address this, a complex frequency-domain modeling method is proposed. By establishing a DDSRF-PLL model using complex transfer functions, analytical expressions for sequence channels are derived, significantly simplifying the system structure. Based on this model, dynamic response analysis reveals the relationship between settling time and sequence magnitudes, demonstrating that the separation time consistently exceeds half a grid period. Simulations validate the theoretical conclusions. These findings provide theoretical and practical guidance for optimizing control strategies and standard development.

Phase Locked Loop (PLL),complex variable function,Dynamic Response