HEM-TD: New Time-Domain Electromagnetic Model for Calculating the Lightning Response of Electric Systems and Their Components

A new electromagnetic time-domain model dedicated to calculating the lightning response of electric systems and their components is presented. It is formulated taking as reference the main features of the frequency-domain Hybrid Electromagnetic Model. A differential aspect of this model is the capability to efficiently address problems involving nonlinear effects, such as soil ionization around grounding electrodes, the surge-arresters operation and the Corona Effect in applications related to the lightning performance of transmission lines. In addition, it is able to consider frequency-dependent effects, for instance that of soil resistivity, with an accuracy compatible with engineering applications. The basic formulation of the model is shown along with the validation of the results it yields by comparison with reliable references, including experimental results.