The unequal round-trip delay of 5G differential protection channels in distribution networks leads to an inability to apply traditional synchronization algorithms and the need to add additional synchronization devices. In addition, the 5G channel has problems such as delay jitter and data anomalies. These will have an impact on the reliability of the protection. To address these problems, a fault self-synchronization method based on variable frequency interpolation is first proposed, where the interpolation method is used to process the data window at a specific moment before the fault after the protection device is activated to realize the synchronization error correction. Based on this, the abnormal data characteristics that the protection may face are analyzed, and the Hausdorff fault discrimination algorithm considering rounded poles is proposed. Finally, a 5G differential protection scheme for distribution network fault self-synchronization that can improve the performance against delay jitter and data anomalies is designed. The scheme is simulated and verified in PSCAD, and the results show that the proposed scheme can effectively improve the performance of anti-delay jitter and data anomaly without additional synchronization devices, and ensure the reliability of protection in the event of various types of faults and the presence of large noise. The proposed scheme can guarantee the reliability of 5G differential protection for distribution networks.