Influence of insulating barriers on positive long air gaps in divergent field

This paper is devoted to the determination of the optimum position of an insulating barrier that increases the breakdown voltage of long air gaps under positive switching and lightning impulse waves. This study is achieved experimentally as well as theoretically using a predictive model of the positive discharge. The latter is a self-consistent model based on an equivalent electrical network. The authors first present the principles of this model and then apply it to the study of the barrier effect. A good agreement has been found between the computed and experimental results