The influence of semi-spherical ground inhomogenity on quasistationary characteristics of linear grounding systems (LGS) was analyzed. For that purpose, firstly electric scalar potential (ESP) distribution in the vicinity of wire electrodes grounding system was determined. Afterwards, corresponding system of integral equations (SIE) was formed having distribution of leakage current from conductor surfaces as unknown function. The SIE is solved using Method of Moments (MoM). In deriving procedure of quasistationar expressions for ESP, quasistationary image theory in flat and modified image theory in spherical semi-conducting mirror are used. The application of proposed model is illustrated with many different examples of grounding systems.