With the increasing penetration of new energy such as wind power and photovoltaic in distribution network

the traditional distribution network is gradually evolving into a complex new power system with multi-source energy supply and two-way power flow. However

frequent power flow switching may lead to reverse power overload of the transformer and accelerate its life decay. Therefore

this paper proposes a multi-time scale life optimization strategy for distribution network transformers facing reverse overload. The regulation mechanism of on-load tap changer (OLTC) and the influence of the load rate on the transformer life loss are analyzed

and then

the coordinated scheduling model of distribution network is constructed. The model aims to reduce the transformer loss cost and the comprehensive operation cost of the distribution network

and realizes the life optimization in the transformer reverse overload scenario through the day-ahead and intra-day rolling optimization scheduling strategy. An example is verified based on the improved IEEE-33 node system. The results show that the proposed method can effectively reduce the reverse load ratio of the transformer under the condition of frequent power flow switching

reduce the life loss of the transformer and reduce the comprehensive operation cost

so as to significantly increase the operation life of the transformer under the reverse overload condition

and improve the safety and economy of the system.