Abstract It has been discussed in various papers, how lack of proximity effect in modelling affects simulations and gives inaccurate results at high frequencies. This paper describes a method for how to include the proximity effect calculations in EMT11 EMT: electromagnetic transients.-based simulations. A subdivision of conductors method is used to calculate conductor (core and sheath) impedances. A full phase impedance matrix is then constructed, including semiconductive layers, insulation layers and a special screen of two conducting materials. Finally the method is tested using the universal line model and is verified against field measurements. It is shown in the paper how including the proximity effect, it is possible to obtain good comparison between measurements and simulations, even for the intersheath mode.