This paper presents the application of the partial element equivalent circuit (PEEC) method in the time and frequency domains for calculating tower surge responses and insulator voltages of an actual transmission tower, and transient performance of grounding systems. Neglecting of electromagnetic retardation effect in the PEEC method in the time domain is proposed to increase efficiency of the method. Incorporation of nonlinear elements such as a flashover model and a soil ionization model with the PEEC method in the time domain is presented. Moreover, an effective way to increase the efficiency of the method in terms of computation time, which consists of the appropriate combination of the PEEC method and the transmission line theory, is proposed. The transmission line model is adapted to combine with the method for reducing elements in the PEEC method. Comparisons of the simulation results by the proposed methods in the time and frequency domains with other numerical methods and with available experimental data show satisfactory agreement. (C) 2012 Elsevier B.V. All rights reserved.