Abstract: By analyzing the typical errors in the bypass platen switching sequence of 110 kV backup automatic switching device in the bypass operation of a certain 110 kV substation, the impact of incorrect switching of bypass platens in the bypass operations on the backup automatic switching trip logic, current logic, and discharge logic are expounded, based on which a kind of bypass platen operation sequence for safety automation device is proposed so as to ensure accurate and reliable actions of backup automatic switching logic in bypass operations.