With a high proportion of distributed generation integration, it is difficult to adapt conventional three-stage current protection to the increasingly complex fault forms of a distribution network. Given the continuous rise of 5G communication, current phasor differential protection with high performance has a broad application prospect in a distribution network, and is no longer subject to the additional high costs such as laying of optical fiber. However, once the 5G communication signals lose synchronization or even get interrupted in extreme cases, the current phasor differential protection will not work normally. Thus a new fast comprehensive protection scheme for active distribution network dealing with abnormal scenarios of 5G communication is proposed. This contains a current amplitude differential protection criterion adapting to the scenario where 5G communication is out of synchronization but not interrupted, and a fast sequential protection criterion adapting to the scenario where 5G communication is completely interrupted. The criteria can be adaptively switched by real-time monitoring of the channel environment. A 10 kV active distribution network model is established in PSCAD/EMTDC. The simulation results show that the proposed protection criteria can operate reliably in different fault scenarios. This work is supported by the Science and Technology Project of China Southern Power Grid Co., Ltd. (No. 0000002020030103XT00046).