To study the temperature distribution of three-generation gas-insulated transmission lines（GIL） and the influencing factors of heat-transfer capacity of insulating gas. In this paper

the nonlinear relationship between material parameters and temperature is fully talen into consideration

the finite element method is used to solve the loss of conductor and shell

and a coupled multiple physical field simulation model is established to solve the temperature distribution. The operating temperature rise of three-generation GIL is calculated by using the model

and the influence of thermal parameters of insulating gas on its heat transfer capacity is analyzed. Finally

the following conclusions are drawn. First

considering the coupling between flow and temperature is helpful to improving the calculation accuracy of GIL temperature field. Second

the shell of the different generations GIL has the same temperature rise at the same conditions

but the conductor temperature rise is related to the thermal properties of the insulation gas. Third

the main factor affecting the heat transfer capacity of insulating gas in GIL is the volumetric heat capacity of gas

and the heat transfer capacity of gas can be changed by adjusting the volumetric heat capacity.