With the widespread adoption of inverter-based resources, the large-signal transient behavior of internal control loops has become a critical factor for protective relaying. This paper develops detailed large-signal transient models for the inverter’s PLL and DC-link control loops and employs time-domain simulations to perform parameter sensitivity analysis. Key parameters—including PLL bandwidth, filter time constants, DC-loop PI gains, and DC-link energy storage components—are varied to assess their impact on relay operation. Simulation outcomes indicate that protective relay response times and selectivity can vary noticeably across parameter settings, though the exact effects depend on specific disturbance scenarios. The study offers a conceptual framework for protection setting in inverter-dominated grids to ensure reliable protection performance.