Abstract This paper deals with the mathematical model based on the transmission line (TL) approach for the simulation of grounding system behaviour at high frequency electromagnetic transients. This paper discusses the possibility of application transmission line approach, when conducting electromagnetic transient analysis of grounding systems. These analyses are important for electromagnetic compatibility (EMC) problems as well as for lightning protection (LP) system efficiency evaluation. Within this paper transmission line model of grounding system with taking into account mutual interactions between grounding system segments is presented.