In view of the problems that the electrified railway in the western mountainous area is faced with the weak external power grid

it is considered to connect the wind and solar power generation along the railway to the weak power grid

and integrate energy storage to provide reliable power for traction load. Therefore

a planning model of siting and sizing with two-stage coordinated optimization for power grid is established considering traction load access. In the first stage

a single-objective distributed generation siting and sizing optimization model with the lowest annual comprehensive cost is established

and the particle swarm optimization algorithm is used to solve the access location of distributed generation

which provides a reference for the location of energy storage in the second stage. In the second stage

the optimization model of siting and sizing for energy storage is established with the objectives of energy storage cost

node voltage fluctuation and power fluctuation

and the multi-objective particle swarm optimization algorithm is used to solve the model. The results show that the access of distributed generation improves the power supply capacity of power grid and ensures the power supply of traction load

while the access of energy storage reduces the power fluctuation of distributed generation and traction load

and ensures the safety of power grid and the reliable power supply of traction load.