Study of the behavior of an electric arc during the passage of an 8/20 µs impulse current and a follow current in a spark gap

The technologies of spark gaps involve two distinct types of current: an impulse current that simulates a lightning strike and a follow current resulting from the persistence of the arc after the impulse. This study shows the behavior of the electric arc with 8/20 µs impulse current followed by a 200 A follow current, using both experiments and numerical tools. The geometry includes a pre-chamber, a main chamber (without separators), and an open outlet. We developed a three-dimensional (3D) numerical model to simulate the arc movement. This model is based on the assumption of local thermodynamic equilibrium (LTE) and operates under unsteady conditions. In our experiments, we use high-speed camera recordings and electrical measurements. A good agreement is observed between the numerical model and the experimental measurements, both in terms of arc shape and arc voltage values.