Active distribution networks with low‐resistance grounding face a significant challenge under the dual‐carbon strategy. When a single‐phase arcing high‐resistance grounding fault occurs, the resulting zero‐sequence current is weak and unstable. Consequently, existing protection schemes for such faults are rendered ineffective. Considering the neutral points of both the main power grid and the distributed generation (DG) using low‐resistance grounding, the work established an arcing high‐resistance grounding fault model for active distribution networks. The current in the faulty feeder was approximately 180° out of phase with the current at the neutral point due to the transient characteristics of the zero‐sequence current in feeders and at the grid's neutral point. The phase difference between the zero‐sequence current in the healthy feeder without DG and the zero‐sequence current at the neutral point of the main power grid was approximately 90°. However, the phase of the zero‐sequence current in the healthy feeder with DG was approximately in phase with that at the neutral point of the main power grid. A protection method for arc high‐resistance grounding faults in active distribution networks with low‐resistance grounding was proposed based on the waveform similarity of zero‐sequence currents. The proposed protection principle was validated via PSCAD simulations. © 2026 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.