For distribution networks below 110 kV with power supply task as main, it′s generally protected in remote backup mode, that is, the protection device is a single configuration. However, When the main protection is refused, the remote backup protection can′t selectively eliminate the fault, which reduces the reliability of power supply to some extent. Therefore, it is necessary to study how to improve the protection selectivity in remote backup mode. In addition, when the integrated protection and control equipment is abnormal, protection and remote control function should be blocked, resulting in the primary equipment runs without protection for a long time. Based on technology accumulation of smart substation, this paper introduces an isomeric double configuration scheme of medium and low voltage protection by adding the intelligent interface to realize redundant configuration with lower cost. This scheme can solve the above problems and ensure the selectivity of remote backup protection.