Abstract Distance protection for inverter‐interfaced renewable energy transmission lines faces challenges from weak infeed characteristics and distributed capacitive currents. Existing time‐domain methods struggle to balance noise immunity with dynamic tracking capability, particularly under weak‐injection conditions where effective signals are easily submerged. To address this, a dual‐frequency synergistic dynamic distance protection scheme is proposed. By constructing a unified state‐space model that integrates power‐frequency and low‐frequency information, the proposed method leverages the high signal‐to‐noise ratio of power‐frequency components to compensate for the limitations of weak active injection. Furthermore, an adaptive Kalman filter (KF) is employed to recursively estimate fault distance and resistance, eliminating the ‘data window effect’ of static algorithms. Simulation results demonstrate superior robustness: under a 20 dB noise environment, the steady‐state error is constrained within 0.5 km; under 2% weak injection with a 300 Ω high‐resistance fault, the relative error is reduced to 1.7%. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.
Wang et al. (Sun,) studied this question.