In this paper, Intelligent water drop algorithm (IWD) is used to analyze single overhead line connected to grid-grounded arrester. In this approach, at first Norton’s equivalent circuit of the overhead line over lossy soil is computed by method of moments (MoM) and then for the problem under consideration, a nonlinear equivalent circuit in the frequency domain is proposed. Finally applying intelligent water drop algorithm (IWD), nonlinear analysis is efficiently analyzed and transient voltage across the arrester is easily computed. Comparison of the achieved voltage with transient solvers shows good agreement as well as fast run-time.