Gas-insulated transmission line (GIL) has many advantages

such as large transmission capacity

small occupation of land

small maintenance and small environmental impact

and has gradually become the first choice to replace overhead lines in special environments. Aiming at a hybrid transmission line system with two 500 kV overhead lines partially reformed to GIL

a GIL-overhead line hybrid transmission line model is established in PSCAD based on the structure and electrical parameters of GIL and overhead line

and short-circuit faults are set up at different positions of the line for simulation

so as to study the differences between fault characteristics. And suggestions for line reconstruction are proposed based on the simulation results.