The development of low-carbon energy systems and renewable energy sources (RESs) are critical to solving the energy crisis around the world. However, renewable energy generation control strategies lead to fault characteristics such as fault current amplitude limitation and phase angle distortion. Focusing on large-scale renewable energy transmission lines, the sensitivity of traditional current differential protection and distance protection may be reduced, and there is even the risk of maloperation. Therefore, a suitable transmission line model is established, which considers the distributed capacitance. Afterward, a novel dynamic state estimation based protection (DSEBP) for large-scale renewable energy transmission lines is proposed. The proposed DSEBP adopts instantaneous measurements and additional protection criteria to ensure the quick action and reliability. Finally, faults are identified by checking the matching degree between the actual measurements and the established transmission line model. The performance of the proposed DSEBP is verified through PSCAD/EMTDC and real-time digital simulator (RTDS) hardware-in-loop tests. The results demonstrate that the proposed DSEBP can identify various types of faults quickly and reliably. Meanwhile, the proposed DSEBP has a better capability to withstand fault resistance and disturbance.