Abstract: The high voltage transmission line protection is usually dual-configured, which has high reliability. However, only one set of protection operates when another one is blocked due to current transformer（CT） disconnection. As it takes a certain time to repair the disconnected CT, the reliability of line protection decreases significantly when only one set of protection operates. To deal with above difficulties, under the condition of smart substation, the currents of the lines that connect to the busbars which connects to the double ends of the protected line can be acquired based on the substation area protection information sharing platform. Then, multiple differential protection criteria were formed, and an emergency protection scheme for high voltage transmission line consisted of the criteria was proposed, which has high reliability and can deal with the CT disconnection. Theoretical analysis and simulation results indicate that the proposed emergency protection scheme is capable of remarkably reducing the maloperation probability and operation failure probability of protection and immune to the abnormities of multiple current transformers.