In order to solve the problem that the traditional distance protection for AC transmission lines is influenced by commutation failure, a novel distance protection based on substation area information sharing is proposed in this paper. The distance protection can detect the fault position correctly when commutation failure do not occur. Thus, to avoid the influence of commutation failure,the distance protection can be blocked when the commutation failure is detected. The current at inverter DC side is approximately equal to the current at AC side when the inverter commutates normally, and the DC current will be larger than the AC current when commutation failure occurs, which can be used to recognize the commutation failure. Based on the detection and sharing of commutation failure information, the traditional distance protection can be improved. A HVDC system model is built in PSCAD/EMTDC simulation environment to test the performance of the improved method. Simulation results show that the novel method can detect the internal and external faults correctly when different types of faults occur, avoiding the influence of commutation failure. This work is supported by National Natural Science Foundation of China (No. 51477061) and Science and Technology Project of Guangdong Power Grid Limited Liability Company (No. GDKJXM20162476 and No. 036000KK52160029).