Abstract: Aiming at the problem that the local standby power automatic switching device is adopted in certain regional main grids, and some bus outlets do not have the function of mutual switching, a new type of remote chain type standby power automatic switching device based on smart substation system is proposed. This paper considers the action logic design and transformation scheme of the standby power automatic switching protection between multiple substations under the chain connection of substations. It can realize the transmission of information flow without changing the existing network architecture, and further compress the power outage time after some specific faults, which can effectively improve the reliability of power supply.