Effect Of Earth Discontinued To The Electrical Field Distribution In Rod-plane Air Gaps Under Lightning Impulse

This paper, will present some results of investigations carried out on electric field distribution on the surface of a discontinuous plane of short rod-plane air gap arrangement. For this purpose, we have used different results obtained by an experimental model and a numerical method for computation used the finite elements methods (FEM). The effect of interface on the field stress has also been studied, As a result, the interface locally reinforces the electric field, and then the electric field increases at the interface may lead to a discharge between the high voltage rode and the interface. In the vicinity of the interface, we have observed a kind of discontinuity in the evolution of the electric field intensity. This latter becomes greater than the value obtained in the case of gaps with homogeneous plane earth. The electric field distribution, obtained by means of the computational procedure, is in good agreement with the experimental results.