Abstract: Substation renovation often involves a long time and a wide range of power outage, which has a serious impact on the resident life and the production of enterprises. In view of the decommissioning and replacement of switchgear in county 35 kV substations, it is necessary to explore the way of on-line operation to carry out transformer substation load switching without power failure. Taking the 35 kV Dakuang Substation GG1A switch cabinet replacement construction as an example, this paper studies the application of the new technology of live work in the implementation of the substation switchgear transformation without power failure, summarizes the operation process, classifies the division of specialization, and completes the substation outlet load transformation without power failure in the form of live work, realizing "zero user perception and zero load loss" in the whole station switchgear transformation process.