Transformer is an important equipment for power transmission

so its overhaul and decommissioning strategy directly affects the safe and economic operation of the power grid.The transformer overhaul strategy and decommissioning strategy are strongly coupled

so optimizing the overhaul or decommissioning strategy alone can only obtain a locally optimal solution.Considering the impact of overhaul on the operating state of transformers

a joint optimization double-layer model of transformer overhaul and decommissioning is proposed. In the upper layer

a decommissioning time optimization model is established with the objective of minimizing the equivalent annual cost of transformer operation.In the lower layer

an overhaul optimization model is established with the objective of minimizing the total annual overhaul cost during the transformer's remaining life. Quantum-snake optimizer(Q-SO)algorithm is proposed to solve the overhaul optimization model

applying quantum bit coding to improve the applicability of the snake optimizer in the overhaul optimization model

and improving the economy and reliability of the overhaul strategy by the improved snake optimizer. The 110 kV transformer is taken as an example to verify and analyze the effective of the model.The results show that the model proposed in this paper can effectively reduce the cost of transformer operation and at the same time improve the reliability of grid operation

contributing to the improvement of the automation and intelligence level of equipment management for power grid enterprises.